Table of contents

Current study aims at simulating fluid flow due to a deformable heated surface in an otherwise static viscoelastic fluid obeying Walters-B model. Velocity of the surface is supposed to grow as time from its initiation of motion progress. Simulations in this work are based on the assumption of quadratic surface temperature distribution. Temperature rise attributed to the frictional heating effect is accounted for in the analysis. By choosing appropriate base functions, homotopy solutions are developed for reasonably large values of material fluid parameter. Reliability of the analytical results is established by computing averaged squared residual of the system. The contributions of the surface acceleration and elasticity on the boundary layer formation are enlightened through the plots of velocity components and temperature. Skin friction measuring the stress experienced by the surface is evaluated and examined under different controlling parameters. The paper also presents a numerical solution using NDSolve of MATHEMATICA in a special case of steady flow, and such solution agrees very well with the corresponding homotopy solution.

Cosmological implication of a generalized model of two scalar and two vector fields, in which both scalar fields are non-minimally coupled to each vector field, is studied in this paper. In particular, we will seek a set of new anisotropic power-law inflationary solutions to this model. Additionally, the stability of the obtained solutions will be examined by using the dynamical system approach. As a result, we will show that this set of solutions turns out to be stable and attractive during the inflationary phase as expected due to the existence of the unusual couplings between two scalar and two vector fields. Notably, we will point out that the existence of phantom field will lead to an instability of the corresponding anisotropic power-law inflation.

The purpose of this study is to investigate and optimize the process parameters for bovine serum albumin (BSA) adsorption onto calcium bentonite (CaB) using the Box-Behnken experimental design method. Calcium bentonite was characterized using FT-IR, SEM, XRD, zeta potential measurements, and Boehm titration methods. The BSA adsorption capacity of calcium bentonite was modelled with respect to pH (2.8, 4.8, and 6.8), temperature (25 °C, 32.5 °C, and 40 °C), and initial protein concentration (0.1–1.2 mg ml⁻¹) using the Box-Behnken experimental design method. The Design Expert 13.0 software was used to optimize the process conditions and obtain three-dimensional response surface graphs. A regression model, which gives the relationship between the process parameters and BSA adsorption capacity, was obtained using Design Expert software. The developed model showed that the most effective parameter on adsorption was the initial protein concentration followed by pH and temperature. The maximum adsorption capacity was obtained about 171 mg/g under optimal conditions (pH 4.8, 40 °C, and 1 mg ml⁻¹ of initial BSA concentration). BSA adsorption onto CaB fit the pseudo-second order kinetic model. This study showed that process parameters for BSA adsorption can be effectively investigated and optimized using the Box-Behnken experimental design method with a fewer number of experiments.

Glasses were prepared from nominal wollastonite-lithium silicate in the ratios of 87.5/12.5, 75/25, 50/50, 25/75, and glasses respectively. However, the glass of 25/75 ratio run through devitrification into lithium silicate and little quartz whereas, the other three ratios formed transparent glasses. The thermal behavior of glasses shows a decrease in the main exothermic temperature; which goes along with an increase in the lithium silicate content. Sintering of such glasses at the crystallization temperature given by differential thermal analysis (at 607 °C + 705 °C and at 661 °C) or at one step at 1000 °C, indicates the formation of three phases of pseudowollastonite [Ca₃(Si₃O₉)], wollastonite (CaSiO₃), and lithium silicate (Li₂SiO₃). The results of the in-vitro test by means of soaking in SBF for two weeks tracked by scanning the sample's surface and measuring the calcium and phosphorous ions using induced coupled plasma (ICP) in the SBF, exhibited that samples had improved talent to accelerate the mineralization of calcium phosphate and that the ratio of Ca/P declined from 2.55 to 1.86 upon increment of the Li₂O ratio. The X-ray analysis shows the formation of hydroxyapatite on the sample's surfaces. The biocompatibility and thermal properties of the premeditated glass ceramics secure exceptional properties and can be used to impress different biomedical applications.

This paper presents an experimental investigation into the estimation of specular gloss from the colorimetric data. The 28 samples were selected from the Natural Color System (NCS) gloss scale, which had different combinations of lightness and gloss levels. The samples' spectral reflectance and colorimetric data Y and L* were measured by a d:8° geometry reflectance spectrophotometer in both SCE (Specular Component Excluded) and SCI (Specular Component Included) modes. Additionally, the specular gloss of the samples at three common angles 20^◦, 60^◦, and 85^◦ was measured using a gloss meter. The correlation and relationship between DY_SCI-SCE and DL*_SCI-SCE and the specular gloss values measured for the samples at different angles were evaluated and analyzed with linear and second-polynomial regression functions. The results were validated with a different set of data acquired from 32 random solid-coated samples. The results showed the best fitting was achieved at 60^◦ of gloss measurement with a second-polynomial function. As the specular gloss of DY decreased, like in a matt sample, the estimation error of specular gloss increased with a large error of over 10%.

Moisture content is an important parameter of solid waste degradation in landfill. The traditional gravimetric method used for determining the moisture content of sludge is very time-consuming and cannot achieve online measurement of sludge moisture content. This paper proposes an ultrasonic reflection method to measure the moisture content of sludge on-line, the sludge only needs to be dried once, and then the online measurement can be realized. The specific process is as follows: by analyzing the ultrasonic characteristic parameter under different moisture content, the quantitative relationship between them can be obtained, and then the sludge moisture content can be deduced by the ultrasonic characteristic parameter. In this paper, the relationship between the ultrasonic characteristic parameter of the three sludge and the moisture content was analyzed, and the quantitative relationship was determined. The sludge moisture content calculated by this method is very close to the actual value. This method provides a new research idea for the online measurement of sludge moisture content.

In this work, we compute the Lewis and Berry phases for a gravitational wave interacting with a two dimensional quantum harmonic oscillator in the transverse-traceless gauge. We have considered a gravitational wave consisting of the plus polarization term only. Considering the cross polarization term to be absent makes the Hamiltonian separable in terms of the first and the second spatial coordinates. We then compute the Lewis phase by assuming a suitable form of the Lewis invariant considering only quadratic order contributions from both position and momentum variables. Next, we obtain two Lewis invariants corresponding to each separable part of the full Hamiltonian of the system. Using both Lewis invariants, one can obtain two Ermakov-Pinney equations, from which we finally obtain the corresponding Lewis phase. Then making an adiabatic approximation enables us to isolate the Berry phase for the full system. After this we obtain some explicit expressions of the Berry phase for a plane polarized gravitational wave with different choices of the harmonic oscillator frequency. Finally, we consider a gravitational wave with cross polarization only interacting with an isotropic two dimensional harmonic oscillator. For this we obtain the Lewis phase and the total Berry phase of the system, which is found to be dependent upon the cross polarization part of the gravitational wave.

Fabrication of tunnel field effect transistor (TFET) confronts various challenges, one of which is random dopant fluctuation (RDF), which diminishes the benefits associated with low subthreshold swing (SS) and high I_ON/I_OFF ratio. By conducting physics-based 2D analytical modelling, this paper proposes a magnesium silicide/silicon (Mg₂Si/Si) heterojunction-based doping less double gate tunnel field effect transistor (HB-DL-DGTFET). This work utilizes the concept of charge plasma to tackle the issues of RDF. The analytical analysis in this study is based upon the determination of the center-channel potential by solving 2D Poisson's equation, considering appropriate boundary conditions. Here, surface potential, electric field, energy bands, drain current and threshold voltage are extracted mathematically. In addition to the aforementioned parameters, several other analog performance parameters like transconductance, drain conductance, device efficiency, intrinsic gain, output resistance and channel resistance have also been studied in this context. The analytical findings have been duly validated using the ATLAS TCAD device simulator. Furthermore, this work focuses on exploring proposed device reliability through an investigation of, the influence of interface trap charges (ITC), present at the Si/SiO₂ interface. The study analyses ITC's impact on analog performance and the obtained results are compared with that of conventional doping less DGTFET (C-DL-DGTFET). The simulation results reveal that HB-DL-DGTFET exhibits greater immunity against ITC. Thus, validating the potential of HB-DL-DGTFET as a superior candidate for low-power switching applications.

Reducing surface roughness and using thermal interface materials (TIMs) at the interfaces between a thermoelectric generator (TEG), heat source, and heat sink are effective strategies for decreasing the thermal contact resistance (TCR) and enhancing the TEG performance. To evaluate the influences of parameters such as the surface roughness, the thermal conductivity of TIM and loading pressure, we conducted experiments to measure the open-circuit voltage and output power of the TEG under various installation conditions. We also analysed the changes in TCR and temperature difference across the TEG module. The experimental findings were validated with numerical simulations using COMSOL Multiphysics under specific conditions. Our results revealed that reducing surface roughness and using TIM could substantially reduce the TCR, increase the temperature difference across the TEG, and increase the output power from the TEG. In our experiments, we used a temperature controller, cartridge heaters and thermocouples to regulate and record the temperatures of the heat source and heat sink. When maintaining a temperature difference of 53 K between the heat source and heat sink, and loading pressure set at 0.2 MPa, without using TIM, as the surface roughness decreased from 2.2 μm to 0.37 μm and to 0.03 μm, leading to a reduction in the TCR from 0.22 K W⁻¹ to 0.17 K W⁻¹ and to 0.13 K/W. Simultaneously, the open-circuit voltage increased from 1.32 V to 1.65 V and to 1.86 V, and the maximum output power increased from 0.26 W to 0.44 W and to 0.58 W. Additionally, when the surface roughness was 0.37 μm, after using TIM with thermal conductivity of 1 W/m-K, 2 W m⁻¹-K⁻¹, and 5 W m⁻¹-K⁻¹, the open-circuit voltage reached 1.44 V, 1.74 V and 1.94 V, respectively, and the maximum power reached 0.31 W, 0.51 W and 0.65 W, respectively.

At present the superconducting diode effect (SDE) attracts a lot of attention due to new possibilities in the superconducting electronics. One of the possible realizations of the SDE is the implementation in superconducting hybrid structures. In this case the SDE is achieved by means of the proximity effect. However, the optimal conditions for the SDE quality factor in hybrid devices remain unclear. In this study we consider the Superconductor/Ferromagnet/Topological insulator (S/F/TI) hybrid device and investigate the diode quality factor at different parameters of the hybrid structure. Consequently, we reveal important parameters that have crucial impact on the magnitude of the SDE quality factor.

Controlled electrochemical reactions on chromium (Cr) thin films have been employed to create micro- and nano-scale patterns using a scanning probe-based patterning process called electrolithography (ELG). The electrochemical reaction produces a liquid material. The ELG process, being a local anodic oxidation-based technique, is significantly affected by several factors, including various ambient conditions. In this article, we explore the effects of temperature on the said electrochemical reaction-induced liquid material formation process. Keeping other ambient conditions constant, the temperature is varied over a large range, and we observe that a 40 °C change in temperature results in a 20-time change in the radial spread of the liquid region. This observation is thereafter explained by the effect of temperature on three different parameters affecting the rate of electrochemical reaction. Thus, based on this study, we can say that temperature is one of the most crucial parameters which can be used to confine the lateral spread of the formed liquid region and thereby improve the resolution of the patterns created using the ELG technique.

The nitrogen ions of the Penning ion source are bombarded on commercially available pure titanium substrates in pulses of about 5.6 μs duration. A thin film (∼500 nm) of multiphase titanium nitride is produced without additional heating of the substrate. The surface modification is studied for various energies of implanted ions at a low flux density. The 2.4 × 10⁹ ions of specific energy are bombarded on the sample in each single pulse of the ion. Each sample is exposed to one thousand such pulses at a repetition rate of 0.1 Hz. The corresponding energy flux was transferred to the sample, promoting the growth of a thin nitride layer. X-ray diffraction (XRD) analysis demonstrates the formation of a monocrystalline multiphase titanium nitride thin film. The XRD spectra show the multiphase reflections of Ti₄N₂ (111), Ti₉N_3.87 (009), and Ti₁₂N₇ (0012) that depend on the energy of the ion beam. Ti₄N₂ is observed to be the dominant phase in this ion implantation process. The morphological and compositional changes of ion implanted samples are investigated using field emission scanning electron microscopy (SEM) along with energy dispersive x-ray spectroscopy (EDX). Raman scattering analysis of treated samples verified the XRD results. The penetration depth of nitrogen ions inside the titanium is calculated using the SRIM code. Vickers hardness has improved three times compared to the original sample.

Solvent influence on the photophysical and electronic properties of 1-Chloro Adamantane (CAD) are investigated using experimental and computational methods. Measured UV–vis absorption of CAD in various solvents exhibits substantial solvatochromatic shifts with respect to the solvent polarity. As a result of this, optical absorption of CAD undergoes the bathochromic shifts in the nonpolar solvents and hypsochromic shifts in the polar solvents with respect to polarity. Theoretical computations of EOM-CCSD and CIS quantum chemical methods calculated by means of SMD solvation model demonstrate the solvent influence on the electronic structure of CAD which are in good agreement with the experimental results. Computed results show prominent solvation effect on Lewis and non-Lewis occupancies. Large excited state dipole moment of the CAD in various solvation suggests excited states are more polarized than the ground state. In addition to this, molecular polarizabilities and energies of HOMO and LUMO show dominant solvent effects on the chemical reactivity of the CAD upon solvation. This solvent specific behaviour of CAD finds applications in optical filters with its significant hydrophobic nature.

In the context of Tsallis entropy, we explore the connection between the law of emergence and the thermodynamic laws from a more accurate non-equilibrium perspective. Here, the equilibrium Clausius relation does not conform to the standard energy-momentum conservation. Therefore, an effective gravitational coupling is introduced to rewrite the field equation similar to general relativity, and the corresponding generalized continuity equation is obtained. As a result, thermodynamic laws were modified with the non-equilibrium energy dissipation and entropy production terms, using which we derive the law of emergence. The investigation of the law of emergence and the entropy maximization principle with Tsallis entropy in the non-equilibrium perspective shows that both result in the same constraints as obtained in other gravity theories and the equilibrium context of Tsallis entropy, except for an additional constraint on the Tsallis parameter as a result of extra entropy production. Consequently, the thermodynamic interpretation of the expansion of the universe stays valid even with quantum corrections to the horizon entropy since the correction terms in Tsallis entropy can be treated as the quantum corrections to Bekenstein-Hawking entropy.

A submarine moving at relativistic horizontal velocity sinks in Earth's rest frame due to length contraction while appearing to float in its own frame. Using spacetime geometry and the Lorentz transformations, we show that the resolution lies in how metric components transform between reference frames in relative motion. This solution frees us from assumptions made in previous studies on how a Newtonian gravitational force should transform. The method of background Lorentz transformations is technically simpler than previous treatments in the framework of general relativity. Moreover, we find a novel and intuitive understanding of the paradox, and correct an erroneous expression for the gravitational force obtained by Supplee and used again in the literature.

Enhancing the design and performance of micronozzles could lead to novel applications and advancements in propulsion systems, making the exploration of micronozzles crucial for the future. This paper critically examines the feasibility of utilizing macroscopic property-based Kn as indicator for defining the breakdown region during the transition from the NS solver to the DSMC solver in micronozzle simulations. The aim is to specify a parameter that can be calculated from both NS and DSMC simulations, making it suitable for implementation in hybrid simulations that dynamically switch between the two solvers. The results show that the density-based Kn accurately represents the continuum breakdown, and it exhibits an earlier breakdown compared to pressure and temperature-based Kn values. The study also analyzes the rarefaction effects and introduces the rarefaction parameter (RP), quantifying the increase in Kn for a unit change in the non-dimensionalized distance. The findings demonstrate that at very low exit pressures, the rarefaction effects increase rapidly as the flow moves towards the nozzle exit, leading to a transition from the continuum to the rarefied regime. The hybrid NS-DSMC simulations show good agreement with experimental data, validating the proposed approach. Additionally, the research examines the effect of back pressure on the RP and identifies the transition regime based on the slope of the RP curve. Therefore, the manuscript provides detailed insights into novel elements, such as the quantification of rarefaction within the nozzle using the RP, the classification of the nozzle into different regimes (continuum, slip, and transition), the definition of an easily obtainable parameter for switching between NS and DSMC methods, and an examination of the contributions of the shear stress term and heat addition term to non-equilibrium conditions.

We study Noether symmetries of a class of non-minimally coupled scalar field in a background spatially flat Friedmann-Robertson-Walker (FRW) spacetime. We explore the model symmetries and its conserved currents and charges. Especially, the scaling symmetry, its possible break down and outcomes of such a symmetry breaking are treated in details. A suitable potential of the non-minimally coupled scalar field is adopted which is necessary to get a symmetric Lagrangian of the system including gravity, scalar field and ordinary matter density. We use the obtained charge and the adopted potential in the equations of motions to see the role of the non-minimal coupling (NMC) on the cosmic expansion. We study evolution of the scalar field in the phase space of the model and explore the stability of the obtained critical point. In this manner we derive a relation that relates the cosmological constant and gravitational constant via a unique identity which reflects the scaling symmetry breaking in the space (a, φ).

In this paper, we focus on the Gauss-Bonnet gravity theory, which includes higher curvature corrections to the Einstein-Hilbert action. We investigate the possibility of obtaining a bouncing cosmology in this modified theory of gravity, where the Universe contracts until a minimum scale factor and then expands again. We examines four Higher-Order Gauss-Bonnet Gravity theory models within the FLRW formalism, emphasizing the Universe's bouncing behavior to resolve Big-Bang cosmology's singularity problem. We establish cosmological constraints over cosmic time, investigate bounce conditions, reconstruct Higher-Order Gauss-Bonnet Gravity for a hyperbolic expansion law, and extend this reconstruction using the red-shift parameter to derive cosmological parameters signifying accelerated Universe expansion. The stability of these models is subsequently evaluated through an arbitrary speed of sound function for late-time stability assessment. Our results suggest that the Gauss-Bonnet gravity theory can provide a viable mechanism for a non-singular bounce in the early universe.

In this paper, we study the geodesic deviation between two nearby geodesics. For this process, we calculated the geodesic equation and radial motion of test particles. Also, the radial and angular tidal forces have been investigated using the curvature tensor in tetrad form. The radial tidal forces in 4D charged Einstein-Gauss-Bonnet gravity black hole show a tidal effect with a small value of radial coordinate r. The angular tidal forces show converse behavior as compared to the radial tidal forces at the short value of radial coordinate r. The radial and angular tidal forces have the same behavior at the immense value of radial coordinate r. The geodesic deviation paths depend on the charge Q parameter and Gauss-Bonnet parameter α of the black hole. We have compared our result with the 4D uncharged Einstein-Gauss-Bonnet gravity black hole and Reissner-Nordström with consideration of two kinds of initial conditions.

Clinical image retrieval plays a pivotal role in modern healthcare for diagnostics and research, but prior research has grappled with the challenge of achieving high accuracy due to limited filtering techniques. The proposed method includes statistical distance measurements for similarity comparison and a machine learning technique for image filtering. Throughout this framework, the search area for similarity matching is reduced by first filtering away irrelevant images using the probabilistic outcomes of the Support Vector Machine (SVM) classification as class predictions of search and database images. Resizing is done as part of the preprocessing. Then, using Principal Component Analysis (PCA), the preprocessed data's textural features, visual characteristics, and low-level features are extracted. The study also suggested an adaptive similarity matching method centered on a linear integration of feature-level similarities on the individual-level level. The precision and ranking order details of the most appropriate images retrieved and predicted by SVMs are considered when calculating the feature weights. The system continually alters weights for every distinctive search to generate beneficial outcomes. The supervised and unsupervised learning strategies are studied to link low-level global image features in the generated PCA-based Eigen Space using their high-level semantic and visual classifications to reduce the semantic gap and enhance retrieval effectiveness. The ground-truth database used in experiments has 1594 unique medical images with 3 different databases. Our method significantly improves the precision and recall rates in image retrieval tasks by combining sophisticated feature extraction, data-driven algorithms, and deep learning models. Research obtained an impressive accuracy of 0.99, demonstrating the effectiveness of our approach. This novel methodology addresses the limitations of prior research and provides a robust and reliable solution for clinicians and researchers in the medical field seeking to access and analyze relevant clinical images.

All-optical simultaneous OR and NAND gates design is proposed using a simple nonlinear photonic crystal ring resonator based on the chalcogenide glass (Ag₂₀As₃₂Se₄₈) material which is one of the promising materials for all-optical devices. The structure consists of an octagonal ring resonator between two waveguides, which uses the switching threshold mechanism based on the Kerr effect to perform two simultaneous logic gates functions. The plane wave expansion (PWE) method is used to obtain the band diagram in the proposed structure, and the two-dimensional finite difference time domain (2D-FDTD) method is used in the simulation to evaluate the performance of the proposed design. The resonance wavelength is 1551.3 nm, with a high transmission and coupling efficiency of about 100%. The proposed optical OR and NAND logic gates have high contrast ratios of 21.15 dB and 28.19 dB, respectively, with a quality factor of 596.65. The operating power intensity of the proposed structure is 1 kW μm⁻², and the threshold power intensity is obtained at 2.8 kW μm⁻². The proposed gates provide transmitted power of not less than 0.5. The size of the structure is 20.5 μm × 18.17 μm. The proposed structure is compact, works on low operational power intensity, and has the ability for dense integration. The simplicity and small size of the structure make it easy to fabricate for future integration in all-optical circuits.

Space based gravitational wave detectors require a precision relative attitude pointing control in science mode. Their configuration drifts under the influence of perturbations. The spacecraft and telescope optical assembly attitude control loops need to respond to this change in real time. In particular, the constellation reference attitude of the detectors orbiting the earth changes much more than the detectors orbiting the sun, which posing a great challenge to the control system. This article focuses on the constellation attitude tracking problem of the space gravitational wave observatory under configuration disturbances, and systematically analyzes the evolution of the constellation reference attitude. A control method based on finite frequency optimization combine with an improved error-disturbance based observer is proposed. Numerical algorithm simulations show that the method can obtain precise attitude tracking in the measurement bandwidth while effectively suppress the unknown disturbances. Compare with the disturbance based observer controller, the overall error can be reduced by 55% of the original.

In this article, a new co-simulation method was presented for high-temperature superconducting (HTS) magnetic levitation (Maglev) systems by utilizing H-formulation that is implemented in COMSOL Multiphysics^®. A comparative study was conducted to evaluate the curve negotiation performance, which is closely related to its stability, of the HTS maglev vehicle running on a multi-surface permanent magnet guideway (PMG). Also, Sperling's ride index method was used to evaluate ride comfort. Different from the existing related models of this subject, the dynamics of free-falling were incorporated into the modelling approach to simulate the actual running conditions of the vehicle. In addition, because of considering the non-stationary dynamics of the induced supercurrent in the HTS domain, the proposed approach and the selected route design provide simulation results that are close to the actual application of the HTS maglev vehicle. The results show that the performance indicators of the co-simulation greatly deviate from those of the existing curve-fitting-based models with increasing velocity.

Our concept of mass has evolved considerably over the centuries, most notably from Newton to Einstein, and then even more vigorously with the establishment of the standard model and the subsequent discovery of the Higgs boson. Mass is now invoked in various guises depending on the circumstance: it is used to represent inertia, or as a coupling constant in Newton's law of universal gravitation, and even as a repository of a mysterious form of energy associated with a particle at rest. But recent developments in cosmology have demonstrated that rest-mass energy is most likely the gravitational binding energy of a particle in causal contact with that portion of the Universe within our gravitational horizon. In this paper, we examine how all these variations on the concept of mass are actually interrelated via this new development and the recognition that the source of gravity in general relativity is ultimately the total energy in the system.

The study of single independent dynamics of calcium ([Ca²⁺]), IP₃, and β-amyloid (Aβ) in neurons provide limited information. Some attempts are reported for the dynamics of two interacting systems of [Ca²⁺] and IP₃, and calcium and Aβ, which gave some novel insights about the phenomena. However, the interactions of these three systems have not been analyzed till date in neurons. Therefore, a novel model is constructed to study the interactions of the spatiotemporal systems of [Ca²⁺], IP₃, and Aβ in neurons. A two-way feedback mechanism between [Ca²⁺] and IP₃, and [Ca²⁺] and Aβ has been incorporated into the model. The model is formulated by coupling three reaction-diffusion equations of [Ca²⁺], IP₃ and Aβ, respectively. This coupling automatically takes care of the indirect two-way feedback process between IP₃ and β-amyloid in neuron cells. The finite element method (FEM) with the Crank-Nicolson scheme (CNS) is utilized to study the contribution of various ER-associated processes like RyR, IP₃R, SERCA pump, buffer approximation, etc on the neuronal interactions of [Ca²⁺], IP₃, and β-amyloid during Ischemia. The numerical findings provide novel insights into alterations in ER handling during Ischemia, resulting in disturbances in the neuronal calcium, IP₃, and Aβ levels, which may cause the advancement of Alzheimer's illness and be responsible for neurotoxicity and cell death.

The eLoran system functions as a robust backup to the Global Navigation Satellite System (GNSS), providing substantial signal power, robust anti-jamming capabilities, and an easily maintainable ground system. Nonetheless, the propagation time delay of the system, primarily driven by the Additional Secondary Phase Factor (ASF), significantly influences the positioning accuracy. Compensating for ASF can effectively enhance the positioning performance. Traditional propagation delay theories frequently yield substantial discrepancies between the predicted and measured values in regions characterized by extended propagation distances and varying topographic features. To address this issue, we conducted ASF measurements within a selected test area using a limited number of measurement points. We employed the ordinary Kriging interpolation method to predict ASF values across the entire test area, and used cross-validation to validate our predictions. The results confirmed the accuracy and effectiveness of the Kriging interpolation algorithm in predicting ASF values within specific regions. The cross-validation demonstrated that the errors remained within acceptable ranges. Furthermore, we applied Ordinary Kriging, Inverse Distance Weighting, and Radial Basis Function Interpolation methods to evaluate the positioning accuracy of the test area before and after ASF correction. Compared to other methods, using the Ordinary Kriging interpolation algorithm for predicting ASF values resulted in a corrected positioning accuracy of up to 68.8 m at various test locations. This approach effectively resolves the challenge of low accuracy in theoretical calculations in complex environments. By utilizing ordinary Kriging interpolation, we required measurements of only a few ASF values within a specific region to create an ASF correction map, addressing the challenges related to inaccurate theoretical calculations in complex pathways and avoiding time-consuming and labor-intensive large-scale measurements. The results of this study offer valuable theoretical support for improving the accuracy of land-based navigation systems.

In this study, the impact of InGaN film thickness and different compositionally graded structures on InGaN relaxation grown on tiled GaN-on-porous-GaN pseudo substrates (PSs) were studied. In addition, the impact of the degree of porosification on the In incorporation and relaxation of InGaN were examined. 82% relaxed 1μm thick In_0.18Ga_0.82N, which is equivalent to a fully relaxed In-composition of 15%, on porous GaN PS was obtained. Additionally, multi-quantum wells (MQWs) grown on the MBE InGaN-on-porous GaN base layers by MOCVD showed ∼85 nm redshift in comparison with MQWs grown on planar GaN. The developed InGaN-on-porous-GaN PSs can provide an alternative route to grow MQW with a high In content which is essential for high-efficiency nitride-based red LEDs.

In the context of non-Hermitian quantum mechanics, many systems are known to possess a pseudo ${ \mathcal P }{ \mathcal T }$ symmetry, i.e. the non-Hermitian Hamiltonian H is related to its adjoint H^† via the relation, ${H}^{\dagger }={ \mathcal P }{ \mathcal T }H{ \mathcal P }{ \mathcal T }$. We propose a derivation of pseudo ${ \mathcal P }{ \mathcal T }$ symmetry and η -pseudo-Hermiticity simultaneously for the time dependent non-Hermitian Hamiltonians by intoducing a new symmetry operator $\tilde{\eta }(t)={ \mathcal P }{ \mathcal T }\eta (t)$ that not satisfy the time-dependent quasi-Hermiticity relation but obeys the Heisenberg evolution equation. Here, we solve the SU(1, 1) time-dependent non-Hermitian Hamiltonian and we construct a time-dependent solutions by employing this new symmetry operator and discuss a concrete physical applications of our results.

Dedicated to the memory of my mother Djabou Zoulikha and to Djabi Smail

In this report, Density Functional Theory (DFT) based calculation using a Quantum Atomistic Tool Kit (ATK) simulator is done for the hafnia-based ferroelectric material. The band structure, projected density of states (PDOS), and Hartree potential (V_H) are taken into account for hafnium oxide (HfO₂) and silicon-doped hafnium oxide (Si-doped HfO₂). Further, we analyze the temperature variation impact on analog parameters and voltage transfer characteristic (VTC) curve of inverter application of Modified Negative Capacitance Field-Effect-Transistor (NCFET) using the Visual Technology-Computer-Aided-Design (TCAD) simulator. The Modified NCFET structure enhances the DC parameters like leakage current (I_OFF) and Subthreshold Swing (SS) compared to the conventional NCFET structure. With the temperature impact, the variation in the parameters of Modified NCFET is discussed at 250 K, 275 K, 300 K, 325 K, and 350 K like transconductance (g_m), output conductance (g_d), early voltage (V_EA) shows the increment as we move from 250 K to 350 K. The short channel effects (SCEs) like Drain Induced Barrier Lowering (DIBL) and Subthreshold Swing (SS) decrease with the temperature fall at 32.98% and 34.74%, respectively. Further, the VTC curve, Noise Margin (NM), and propagation delay of Modified NCFET-based inverter are discussed with the impact of temperature. The propagation delay for the circuit decreased by 67.94% with the rise in the temperature. These factors show that the Modified NCFET-based inverter gives a fast switching performance at high temperatures.

Finding new strategies for the generation and preservation of quantum resources, e.g. entanglement between spatially separated macroscopic systems enables reliable and fertile platforms to study both fundamental quantum physics and fruitful applications such as quantum networks and distant quantum information processing. Here, we want to address how to generate magnon-magnon entanglement (MME) in an optomagnonic system based on the optical Bell-state measurement. To do so, we consider a hybrid optomagnonic system comprising of two identical, but distant dissipative microwave cavities, each containing a ferromagnetic YIG sphere and a superconducting qubit. Besides, each subsystem is driven via an external laser field. We numerically simulate the solution of the corresponding master equation and discuss the time-dependent as well as the steady state entanglement between the distant magnon modes at different interaction regime. Also, the fidelity of the generated entangled states is studied in detail. Generally, the dissipative environmental effects plague the MME, however, it is possible to generate a considerable amount of MME even at the steady state regime. Also, the results show that the robust MME may be enhanced by applying a relatively strong external pump decreasing the relative magnon damping rate as well as increasing the relative qubit-photon coupling strength, while some other parameters involved in the model, i.e. the atomic damping rate and detuning parameter do not considerably affect the amplitude (the maximum value) of MME. Exceptionally, although the magnon damping rate decreases the amount of MME, the entanglement stability takes place in a longer time interval in the strong magnonic damping regime. Moreover, the maximum of the steady state entanglement may be obtained in the moderate magnon-photon coupling regime provided that the system is driven by strong external pumps. Furthermore, the system can generate robust MME at steady state, especially in the small detuning regime. Our further investigations show that the system can provide relatively high-fidelity magnonic entangled states even in the presence of inevitable environmental effects. The proposed model offers an attractive platform for the generation of quantum resources to establish long-distance quantum networks based on magnonic and photonic systems.

Quantum cloning is an essential operation in quantum information and quantum computing. Similar to the 'copy' operation in classical computing, the cloning of flying bits for further processing from the solid-state quantum bits in storage is an operation frequently used in quantum information processing. Here we propose a high-fidelity and controllable quantum cloning scheme between solid bits and flying bits. In order to overcome the obstacles from the no-cloning theorem and the weak phonon-photon interaction, we introduce a hybrid optomechanical system that performs both the probabilistic cloning and deterministic cloning closed to the theoretical optimal limit with the help of designed driving pulse in the presence of dissipation. In addition, our scheme allows a highly tunable switching between two cloning methods, namely the probabilistic and deterministic cloning, by simply changing the input laser pulse. This provides a promising platform for experimental executability.

On the basis of using quantum NEQR (novel enhanced quantum representation of digital image) to display images, a dual chaos system based on quantum logistic mapping is proposed to encrypt quantum images to ensure the security of quantum image transmission. The encryption algorithm is based on quantum logistic mapping and Chen chaos system to generate chaotic sequences, and uses quantum rotation gate operations to rotate and transform each pixel of the quantum image to achieve the effect of image encryption. Traditional quantum image encryption usually uses classical randomly generated sequences to construct the encryption angle of the quantum rotating door. This method combines the randomness of measured quantum with the chaotic system to obtain a truly random sequence. Using this random sequence can better Keep images confidential. Experimental results show that this method has high security and sensitivity to keys. In the sensitivity analysis of the results of the simulation experiment, its NPCR (Number of Pixels Change Rate) values floated around 99.60%. In the field of image encryption, the reliability of image encryption is greatly enhanced.

Usually, the verification of Bell nonlocality involves two main approaches: violation of specific inequalities and utilization of no-inequality methods. In this paper, we continue to develop the inequality methods by deducing the so-called 'Hardy-Bell inequalities (HBIs)' and 'fault-tolerant Hardy paradoxes (FTHPs)' for correlation tensors (CTs) with two inputs and general outcomes. We prove that the HBIs are necessary conditions for a CT to be Bell local and one of the FTHPs is sufficient condition for a CT to be Bell nonlocal. We demonstrate the effectiveness of HBIs in determining the nonlocality of CTs or quantum states when the classical Hardy paradox does not appear or a Bell inequality is not violated. Consequently, our methods can be utilized to explore more correlations having Bell nonlocality. Based on the obtained results, we find a neighborhood of a Hardy nonlocal state, in which all states are all Bell nonlocal.

We investigate the impacts of backward scattering (BS) of non-Kolmogorov turbulence on the entangled perfect Laguerre–Gaussian (PLG) beams. The explicit expressions for PLG quantum entanglement and quantum coherence are derived in the BS case. We find that the introduction of BS reduces the entanglement and coherence, disrupts the initial decay characteristics, and induces the revival of entanglement and coherence, in which sense turbulence may possess a non-Markovian (memory) effect. As the OAM number increases, the non-Markovian feature increases logarithmically. In addition, the universal decay of entanglement and coherence and the non-Kolmogorov effects are also explored.

In this study, we use the concept of l₁-norm coherence to characterize the entanglement of a two–qutrit Heisenberg XXZ model for subject to a uniform magnetic field and z–axis Dzyaloshinskii–Moriya interaction with Herring-Flicker coupling. We show that the temperature, magnetic field, DM interaction, and distance of Herring-Flicker coupling can all control the entanglement. However, the state system becomes less entangled at high temperatures or strong magnetic fields and vice versa. Our findings suggest that entanglement rises when the z–axis DM interaction increases. Additionally, we show that plateau behavior in the entanglement between spins (1, 1) occurs in the XXZ Heisenberg spin system and is influenced by the magnetic field, demonstrating that thermal agitation can weaken entanglement plateaus. Moreover, by setting the strengths coupling of the spin, we quickly recover the isotropic XY and XXX Heisenberg models. Finally, Herring-Flicker coupling affects the degree of entanglement. When Herring-Flicker coupling and temperature are at small values, the degree of entanglement is at its highest. Still, when Herring-Flicker coupling is at substantial values, the degree of entanglement tends to stabilize.

Quantum secure multiparty computation occupies an important place in quantum cryptography. Based on access structure and linear secret sharing, we propose a new general quantum secure multiparty computation protocol for simultaneous summation and multiplication in a high-dimensional quantum system. In our protocol, each participant within any authorized sets only needs to perform local Pauli operation once on the generalized Bell state, then the summation and multiplication results can be output simultaneously, which improves the practicality of the protocol. Moreover, in the privacy computation phase, the decoy particle detection technique as well as the addition of random numbers are applied to blind the privacy information, making our protocol higher privacy protection. Security analysis shows that our protocol is resistant to a series of typical external attacks and dishonest internal participant attacks such as individual attack and collusion attack. Finally, compared with the existing protocols, our protocol not only has higher efficiency but also lower consumption.

The interaction between a light mode and a mechanical oscillator via radiation pressure in optomechanical systems is an excellent platform for a multitude of applications in quantum technologies. In this work we study the dynamics of a pair of optomechanical systems interacting dissipatively with a wave guide in a unidirectional way. Focusing on the regime where the cavity modes can be adiabatically eliminated, we derive an effective coupling between the two mechanical modes and explore the classical and quantum correlations established between the modes in both the transient and the stationary regime, highlighting their asymmmetrical nature due to the unidirectional coupling. Noteworthy, we find that a constant amount of steady correlations can exist at long times. Furthermore we show that this unidirectional coupling establishes a temperature gradient between the mirrors, depending on the frequencies' detuning. We additionally analyze the power spectrum of the output guide field and we show how, thanks to the chiral coupling, from such spectrum it is possible to reconstruct the spectra of each single mirror.

We show that it is possible to reconstruct the quantum state of light in a cavity subject to dissipation at finite temperature. By passing atoms through the cavity it is shown that the decay does not prevent the measurement of s-parametrized quasiprobability distributions. Because such distributions contain whole information about the initial quantized field, it is possible to recover its complete information.

Perfect state transfer has attracted a great deal of attention recently due to its crucial role in quantum communication and scalable quantum computation. In this paper, we propose the perfect state transfer algorithms with a pair of sender-receiver and two pairs of sender-receiver on the complete bipartite graph respectively. The algorithm with a pair of sender-receiver is implemented through discrete-time quantum walk, flexibly setting the coin operators based on the positions of the sender and receiver. The algorithm with two pairs of sender-receiver ensures that the two quantum states are distributed on both sides of the complete bipartite graph during the process, thereby achieving perfect state transfer. In addition, the quantum circuits corresponding to the algorithms are provided. The algorithms can transfer an arbitrary quantum state and can simultaneously transfer two arbitrary quantum states from the senders to the receivers in any case. Moreover, the algorithms are not only applicable to complete bipartite graphs but also to more graph structures with complete bipartite subgraphs, which will provide potential applications for quantum information processing.

This work focuses on investigating an end-to-end learning approach for quantum neural networks (QNN) on noisy intermediate-scale quantum devices. The proposed model combines a quantum tensor network (QTN) with a variational quantum circuit (VQC), resulting in a QTN-VQC architecture. This architecture integrates a QTN with a horizontal or vertical structure related to the implementation of quantum circuits for a tensor-train network. The study provides theoretical insights into the quantum advantages of the end-to-end learning pipeline based on QTN-VQC from two perspectives. The first perspective refers to the theoretical understanding of QTN-VQC with upper bounds on the empirical error, examining its learnability and generalization powers; The second perspective focuses on using the QTN-VQC architecture to alleviate the Barren Plateau problem in the training stage. Our experimental simulation on CPU/GPUs is performed on a handwritten digit classification dataset to corroborate our proposed methods in this work.

In this article, we study the atomic Talbot effect in a three-level ladder-type atomic system, which consists of a strong microwave field having a finite bandwidth and a weak probe field. The upper levels are coupled with a strong position-dependent microwave field, while a weak probe field interacts with lower levels of the atomic system. We find that phase fluctuations associated with a strong microwave field significantly affect the transmission and corresponding intensity of Talbot images. We show that the choice of various parameters is crucial in the presence of phase fluctuation. An appropriate choice along with a pump field can still improve the intensity of atomic Talbot images. We believe that our results are useful for any practical situation where the effects of phase fluctuations are important.

It is shown that the atomic inversion in the Jaynes–Cummings model has an exact representation as an integral over the Hankel contour. For a field in a coherent state, the integral is evaluated using the saddle point method. The trajectories of saddle points as a function of time are on the branches of the multi-valued Lambert function. All of them start at the initial moment of time, but make the maximum contribution to the inversion at different times. If the collapse and the first revival are clearly distinguished, then subsequent revivals are determined by the comparable contributions of several trajectories.

We obtain a time-evolution operator for a forced optomechanical quantum system using Lie algebraic methods when the normalized coupling between the electromagnetic field and a mechanical oscillator, G/ω_m, is not negligible compared to one, i.e., the system operates in the strong-coupling regime. Due to the forcing term, the interaction picture Hamiltonian contains the number operator in the exponents, and in order to deal with it, we approximate these exponentials by their average values taken between initial coherent states. Our approximation is justified when we compare our results with the numerical solution of the number of photons, phonons, Mandel parameter, and the Wigner function, showing an excellent agreement. In contrast to other works, our approach does not use the standard linearized description in the optomechanical interaction. Therefore, highly non-classical (non-Gaussian) states of light emerge during the time evolution.

Quantum networks are a fundamental component of quantum technologies, playing a pivotal role in advancing distributed quantum computing and laying the groundwork for the future quantum internet. They offer a scalable modular architecture for quantum chips and support infrastructure for measurement-based quantum computing. Furthermore, quantum networks serve as the backbone of the quantum internet, ensuring high levels of security. Notably, the advantages of quantum networks in communication are contingent upon entanglement distribution, which faces challenges such as high latency in protocols relying on Bell pair distribution and bipartite entanglement swapping. Additionally, algorithms designed for multipartite entanglement routing encounter intractability issues, rendering them unsolvable within polynomial time. In this paper, we explore a novel approach to distribute graph states in quantum networks, leveraging local quantum coding (LQC) isometries and multipartite states transfer. We also present single-use bounds for stabilizer states distribution. Analogous to network coding, these bounds are attainable when appropriate isometries and stabilizer codes are selected for relay nodes, resulting in reduced latency in entanglement distribution. We further demonstrate the protocol's advantages across various network performance metrics.

In the cryptographic domain, quantum and its real-time hardware simulation make it easier to secure data during communication. Here, using quantum logic, a unique encryption technique called Reversible select, cross, and variation (RSCV) encryption and decryption, which involves swapping input data halves, is shown. In this article using IBM Q, we created a cryptographic encoder and decoder circuit design utilizing various quantum gates. Based on the encoder/decoder circuit, a simple nanocommunication framework is proposed. Further, to explore the application of the noise model, how to utilize this model to create noisy replicas of these quantum circuits to research the impacts of noise that occur for actual device output is shown. To reduce measurement mistakes, measurement calibration is performed using qiskit ignis model. Preparing all 2ⁿ basis input states and calculating the likelihood of counting in the other basis states are the key concepts. The percentage improvement we achieved is 40%, 30%, and 30%, respectively, compared to earlier ones, in RSCV encryption, decryption, and RSCV cryptographic communication architecture for fake provider noise error model. It is feasible to adjust the average outcomes of an additional interesting experiment using these calibrations.

This article investigates the quantum and semi-classical aspects of a three-level atom-cavity system within the context of cavity quantum electrodynamics. The study examines the behavior of the system through a quantum perspective and a semi-classical approximation. The steady-state master equation is solved in the atom-cavity basis, resulting in a closed set of equations describing the atom's level occupancies and the cavity's photon number. The accuracy of the semi-classical approximation is assessed by comparing it with quantum simulations. The research analyzes the system's behavior near the laser threshold, highlighting the interplay between semi-classical and quantum behaviors. Additionally, the conversion of the three-level atom to a two-level atom is explored under specific conditions, enabling an investigation into the weak driving limit. Quantum simulation results are used to validate the proposed approximations. This work contributes to the understanding of atom-cavity interactions and provides insights into the transition from semi-classical to quantum behavior in such systems.

In K-locality networks, local hidden variables emitted from classical sources are distributed among limited observers. We explore genuine Bell locality in classical networks, where, regarding all local hidden variables as classical objects that can be perfectly cloned and spread throughout the networks, any observer can access all local hidden variables plus shared randomness. In the proposed linear and nonlinear Bell-type inequalities, there are more correlators to reveal genuine Bell locality than those in the K-locality inequalities, and their upper bounds can be specified using the probability normalization of the predetermined probability distribution. On the other hand, the no-cloning theorem limits the broadcast of quantum correlations in quantum networks. To explore genuine Bell nonlocality, the stabilizing operators play an important role in designing the segmented Bell operators and assigning the incompatible measurements for the spatially separated observers. We prove the maximal violations of the proposed Bell-type inequalities tailored for the given qubit distributions in quantum networks.

A dual-ring photonic crystal fiber (PCF) is proposed, which not only supports the stable transmission of orbital angular momentum (OAM) modes but also deftly mitigates interference of mode coupling between the two rings. This fiber design possesses two concentric ring-cores and claddings, each constructed from distinct materials, effectively functioning as independent OAM channels. Importantly, the absence of significant mode coupling between the OAM modes of the two ring-cores guarantees unhindered transmission of the dual rings. Remarkably, the outer ring can accommodate 82 OAM modes of transmission and the inner ring can accommodate 34 OAM modes of transmission. High mode quality (>94.13%) is observed for all OAM modes in both inner and outer rings at wavelengths from 1.5 to 1.6 μm. This special design ensures that the modes in the outer ring have excellent performance and also maintains the modes in the inner ring as unaffected by the outer ring to the greatest extent.

We explore theoretically the generation and selective enhancement of difference sidebands in a quadratically coupled optomechanical system in which the membrane is driven resonantly by an additional coherent mechanical driving field. We show that the generation of frequency components at the difference sideband is directly related to the nonlinear optomechanical interactions under two-phonon resonance condition, while an additional weak coherent mechanical driving field acting on the membrane can considerably establish a selective enhancement of difference sideband generation (DSG). Our analytical solution with experimentally achievable parameters demonstrates that even if the input power of the control field is relatively low DSG can be induced and greatly enhanced when the matching conditions are satisfied. It also indicates that the efficiencies of upper difference sideband generation (UDSG) and lower difference sideband generation (LDSG) can be selectively increased about three orders by properly adjusting the frequency and amplitude of the weakly coherent mechanical driving field. Furthermore, we also show that the matching conditions of UDSG and LDSG are modified by the weakly coherent mechanical driving field. The present investigation may help to achieve the practical application of DSG relevant to nonlinear optics, chip-scale optical communications, and precision measurement.

We use the quadrature measurement to generate the novel nonclassical states via the beam splitter with two input states, i.e., a Fock state and a vacuum state. It is interesting to find that the desired target states are the Hermite polynomial excited vacuum states. Our results have shown that the zero-position detection for the position detector, the little photon number in the input state, and the high transmittance of the beam splitter (BS) are beneficial to improve the detection efficiency of finding the output states. The proposed states quantum statistical properties and squeezing effects are also studied in detail via different criteria. Our numerical analysis demonstrates that the output quantum states are new nonclassical states. Compared with the method of photon catalysis, position detection is easier to realize in experiments. Therefore, the results in this paper shall provide theoretical support for the experimental generation of several new nonclassical states.

The diffusive transport in two-dimensional incompressible turbulent fields is investigated with the aid of high-quality direct numerical simulations. Three classes of turbulence spectra that are able to capture both short and long-range time-space correlations and oscillating features are employed. We report novel scaling laws that depart from the γ = 7/10 paradigm of percolative exponents and are dependent on the features of turbulence. A simple relation between diffusion in the percolative and frozen regimes is found. The importance of discerning between differential and integral characteristic scales is emphasized.

In this work, we compute the metric corresponding to a static and spherically symmetric mass distribution in the general relativistic weak field approximation to quadratic order in Fermi-normal coordinates surrounding a radial geodesic. To construct a geodesic and a convenient tetrad transported along it, we first introduce a general metric, use the Cartan formalism of differential forms, and then specialize the space-time by considering the nearly Newtonian metric. This procedure simplifies the calculations significantly, and the expression for the radial geodesic admits a simple form. We conclude that in quadratic order, the effects of a Schwarzschild gravitational field measured locally by a freely falling observer equals the measured by an observer in similar conditions in the presence of a Newtonian approximation of gravitation.

This work focuses on mathematically studying thermoelastic damping (TED) and frequency shift (FS) in micro-scale piezoelectro-magneto-thermoelastic (PEMT) composite beams composed of BaTiO₃-CoFe₂O₄ combination. Pertaining to cutting-edge micro-technologies implemented in several engineering/scientific applications now-a-days, micro-scale doubly clamped (CC), doubly simply supported (SS), clamped-free (CF), and clamped-simply supported (CS) beams are extensively analyzed. The beams are modeled following the linear Euler-Bernoulli assumptions. The first two eigenvalues of all beams are numerically obtained using Newton-Raphson method. The closed-form expressions of TED and FS of all beams are derived analytically. The influences of Classical dynamical coupled (CL), Lord-Shulman (LS) & Green-Lindsay (GL) thermoelasticity theories, beam dimensions, BaTiO₃ volume fraction (Ω_f), and the first two modes (M₁ & M₂) on the TED & FS are meticulously analyzed. Critical thickness (CrTh), critical length (CrLt), and TED (inverse Quality factor) of the beams are numerically obtained and studied. Among other key outcomes, the existence of a critical value of Ω_f is established in the range Ω_f ∈ [0.5, 0.55], at which, the TED and FS display a drastic change in their natures. The outcomes of the present analysis may find immense potential uses in the design and development of PEMT composite micro-beams, and their applications in several areas such as supporting/stiffening other micro/nanostructures, construction works, sensitive sensing applications, etc.

Multiple timescale effects can be reflected bursting oscillations in many classical nonlinear oscillators. In this work, we are concerned about the bursting oscillations induced by two timescale effects in the damped Helmholtz-Rayleigh-Duffing oscillator (written as DHRDO for short) excited by slow-changing parametrical and external forcings. By using trigonometric function variation and authenticating the slow excitations as a slowly varying state variable, the time-varying DHRDO can be rewritten as a new time-invariant system. Then, the critical conditions of some typical bifurcations are presented by bifurcation theory. With the help of bifurcation analyses, six bursting patterns, i.e., 'Hopf/Hopf-Hopf/Hopf' bursting, 'fold/Homoclinic-Hopf/Hopf' bursting, 'fold/Homoclinic/Hopf' bursting, 'Hopf/fold/Homoclinic/Hopf' bursting, 'Hopf/Homoclinic/Homoclinic/Hopf' bursting and 'Hopf/Homoclinic/Hopf-Hopf/Homoclinic/Hopf' bursting, are explored by the slow/fast decomposition method and the other techniques. Our findings provide different forms of the excited state oscillation modes as well as the bursting patterns. In addition, we use the numerical simulation to prove the correctness of the theoretical analyses.

Fractional advection-diffusion equations have demonstrated to be a powerful tool in modeling complex anomalous diffusion in applied science. In this paper, we studied novel linear time-fractional advection-diffusion equations associated with an extension of Mittag-Leffler fractional derivative operator. A useful feature of the used extension is to address the limitations of the Mittag-Leffler fractional derivative model. We, mainly, proposed a numerical approach to provide approximate solutions to linear time-fractional advection-diffusion equations with the studied extended fractional derivative operator. The suggested approach is based on discretizing the studied models with respect to spatio-temporal domain using uniform meshes. A new type of solutions for the studied models was generated numerically using the proposed approach. Besides, a comparative study was conducted to verify the accuracy and feasibility of the proposed approach.

This paper explores the dynamics, microcontroller realization, chaotic, and coexisting attractors controls in the Josephson junction (JJ) spurred by the Wien bridge oscillator (WBO). The JJ spurred by WBO (JJSWBO) is designed by coupling through a gain a resistive-capacitive shunted JJ (RCSJJ) circuit to a WBO. The JJSWBO exhibits bistable periodic, monostable chaotic, and coexisting attractors as well as period-doubling bifurcation to chaos. A microcontroller implementation of JJSWBO is used to establish the dynamical behaviors spotted in JJSWBO during the numerical simulations. Moreover, two configured single controllers are engrossed to subdue the chaotic and coexisting behavior in JJSWBO. Lastly, thanks to the linear augmentation method, the coexisting attractors of JJSWBO are controlled to the desired trajectory.

We study quantum solution for a free particle in a domain bounded by an ellipse and arc(s) of confocal hyperbola(s). We found asymptotic behaviour of energy levels as focal distance tends to zero and show how it is related to the energy levels of limiting wedge billiard. Classical billiard system in the considered domains is integrable due to existence of an additional conserved quantity. There is a corresponding quantum counterpart, and we calculate its eigenvalues.

Porphyrins are planar tetrapyrolic aromatic molecules that serve as a host for the formation of metal coordination complexes, which enable additional capabilities. The 2D porphyrin derivative sheets attracted interest due to their versatility and capacity to interact with other chemicals due to the existence of a core metal ion. Topological descriptors are employed as a predictive technique to determine the physical, chemical, and structural characteristics of molecules by considering the molecular structure of compounds as molecular graphs. This paper investigates the degree and degree sum based descriptors of some potential porphyrin derivative nanosheets, using the edge partition method. We also demonstrate a predictive model for analyzing the electrical conductance of porphyrin derivative nanosheets using degree and degree sum based topological descriptors. Furthermore, the Shannon's information entropies of these porphyrin derivatives are investigated, and the HOMO-LUMO gap of these nanostructures is predicted using these entropy.

We propose an algebraic procedure to obtain ${U}_{q}({{\mathfrak{sl}}}_{3})$ quantum 3j-symbols (quantum Clebsch–Gordan coefficients) appearing in the decomposition of tensor product of symmetric representations. In fact, these symbols will be useful to write the spectral parameter dependent R-matrix elements for any bi-partite vertex model whose edges carry states of the symmetric representations.

We study the extended Kitaev chain with both nearest-neighbor and next-nearest-neighbor hopping terms and find the model system exhibiting nontrivial phases, which can be characterized by a nonzero Berry phase and winding number when the system is in a pure state. While in a mixed state, we investigate the robustness of the topological Uhlmann phases and show how it responses to the presence of next-nearest-neighbor hopping terms. Furthermore, we analyse the complicated behavior of the Uhlmann phase of the extended Kitaev chain at finite temperature as k moves along the Brillouin zone, and we think this may serve as a topological indicator for mixed states in condensed matter systems.

In this article, the higher-order Haar wavelet collocation method (HCMHW) is investigated to solve linear and nonlinear integro-differential equations (IDEs) with two types of conditions: simple initial condition and the point integral condition. We reproduce and compare the numerical results of the conventional Haar wavelet collocation method (CMHW) with those of HCMHW, demonstrating the superior performance of HCMHW across various conditions. Both methods effectively handle different types of given conditions. However, numerical results reveal that HCMHW exhibits a faster convergence rate than CMHW. To address nonlinear IDEs, we employ the quasi-linearization technique. The computational stability of both methods is evaluated through various experiments. Additionally, the article provides examples to illustrate the overall performance and accuracy of HCMHW compared to CMHW for both linear and nonlinear IDEs.

We provide a mathematical treatment, analytical and numerical, for a fluid constructed as an hybrid of the Eyring-Powell and Darcy-Forchheimer fluid models. The Eyring-Powell model departs from the kinetic theory of liquids and it allows for a description of shear stresses and viscous terms. The Darcy-Forchheimer model permits to describe the fluid effects given in a porous media, and it provides non-linear reaction terms when considered as part of the momentum equations. Hence, it is natural to investigate mathematical characteristics of solutions for a fluid flow formulated as a combination of these two fluid models. First of all, we prove boundedness and uniqueness of solutions arising from rough (i.e. in L¹(R) ∩ L^∞(R)) initial data. This is physically relevant, since it means that we are considering general descriptions of the velocity distribution of the fluid, in a media with particular porosity distributions. Afterwards, stationary profiles are obtained by using a Hamiltonian description, and our construction is supported by numerical validating evidences. Furthermore, asymptotic solutions are explored based on an exponential scaling and a non-linear transport Jacobi equation. Finally, a region of validity for this asymptotic approach is provided, and a numerical validation of our asymptotic analysis is presented. Our main conclusion is that a fluid model combining Eyring-Powell and Darcy-Forchheimer characteristics is indeed possible to introduce, and that solutions of potential physical interest, can be obtained.

In this paper, we explore analytical solutions for the (3+1)-dimensional time-fractional modified Korteweg–de Vries Zakharov-Kuznetsov equation, which incorporates a conformable derivative. Our interest in this model is driven by its significant role in simulating ion-acoustic waves in magnetized plasma. We adopt the unified Riccati equation expansion method and the new Kudrashov method to discover soliton solutions. Our approach uncovers various soliton types, such as kink, singular, periodic-singular, and bright solitons. We conduct a thorough analysis of how different parameters affect wave propagation, enhancing our study with descriptive figures and insightful observations. Furthermore, we delve into the modulation instability characteristic of this model. The influence of specific parameters, like wave number and the order of the conformable derivative, on wave dynamics is demonstrated through detailed visualizations. We also present 2D and 3D graphical representations of these solutions.

The gravitational deflection of the ray of light is one of the famous demonstrations that space-time is curved in the General Theory of Relativity predicted by A Einstein, and later demonstrated by different astronomical experimental observations in solar eclipses. In this work, the deflection of light and the impact parameter in the gravitational field of the Sun are calculated through the solutions to the geodesic equations by the methods of the elliptic functions of Jacobi and Weierstrass, around a central gravitational mass, using the solution found by Schwarzschild to the equations of the gravitational field in the General Theory of Relativity. The results obtained were subjected to a comparative study of the deflection of the light ray experimentally. From this analysis, it is demonstrated that the theoretical results obtained by the Weierstrass and Jacobi methods are in the range of the experimental results calculated during the eclipses of the years 1919 to 1973, demonstrating once again the validity of the General Theory of Relativity that all gravitational mass curves space-time.

The multi-stable memristor is a type of memristor that can store multiple conductance states, optimizing information management and improving the efficiency of artificial neural networks such as Hopfield networks. It can improve the performance of Hopfield neural networks by minimizing the synaptic weight between neurons and increasing information storage capacity through its ability to store multiple levels of conductance. This paper presents and discusses a novel Hopfield neural network model composed of two non-identical sub-neural networks coupled by a flux-controlled multi-stable memristor (MCHNN) and its application in biomedical image encryption. Using analysis methods such as bifurcation diagrams, phase portraits, maximum Lyapunov exponent, and basins of attraction, we analyze the dynamics of the MCHNN model associated with coupling strength and initial states. Numerical results show that the proposed MCHNN model is capable of developing rich and complex dynamics, including chaos, double-bubble bifurcations, homogeneous and non-homogeneous coexisting attractors at different positions induced by initial states. To support the numerical results, the MCHNN model is implemented on a ATmega 2560 microcontroller. The results are in very good agreement with those obtained thoeretically and numerically. We exploit the interesting properties of the proposed MCHNN model to generate random bits for biomedical image encryption. We evaluate the robustness and efficiency of the designed image encryption algorithm by carrying out statistical tests and security analyses.

Researchers are still drawn to research the physical molecular and chemical structure of benzenoid hydrocarbons, unsaturated, fully conjugated compounds with hexagonal arrangements that exhibit remarkable features in relation to aromaticity. For chemical graphs in many dimensions, structures, or networks, topological indices or numerical descriptors have been employed for decades to link key physicochemical parameters with crucial molecular structural features including melting, boiling point, enthalpy, and cyclicity. For this work, the inverse degrees of the molecular or chemical structure or graphs being studied are used to calculate the reverse-degree-based topological indices. In molecular graph theory, reverse-degree-based topological descriptors are a relatively new method for analyzing chemical networks and structures. In this study, we suggest a reverse-degree-based topological representation. We computed particular types of descriptors of two-dimensional (2-D) coronene fractal formations with a variety of reverse-degree-based topological indices, such as the reverse-degree-based topological index of the first, second, and hyper Zagreb, forgotten, geometric arithmetic, atom-bond-connectivity, and the Randic index.

Compared to integer-order chaotic systems, fractional-order chaotic systems have more complex dynamical features due to the introduction of order. The application of fractional-order chaotic systems to chaotic cryptosystems makes the cryptosystems with higher security properties. In this paper, we developed a new 3D fractional-order chaotic system from a 3D integer-order chaotic system, and investigate the dynamical behaviors of this fractional-order system with different parameters and orders. Moreover, self-excited attractors appeared at lower orders through circuit simulations. Furthermore, the synchronization of the new fractional-order chaotic system in the presence of systematic uncertainties and perturbations was achieved using the sliding mode control technique, which sets the stage for the implementation of communication. Finally, offset boosting control was used to investigate the utility of the new chaotic system in engineering applications.

In this paper, the two-parameter space bifurcation of a three-dimensional Chameleon system is investigated. It is called Chameleon since the type and the number of the system equilibrium are adjustable for different parameter configurations. Aided by the computation analysis, the graphic structures of two-parameter bifurcation of the Chameleon system are characterized for the first time. With different two-parameter configurations, the bifurcation evolution shows that various self-excited and hidden attractors exist. In addition, numerical demonstration of the two-dimensional slice through the attraction basin space is presented. The results show that the basin of attraction of the typical hidden chaotic attractor does not associated with the origin, which makes the attractor difficult to be numerically localized and experimentally observed. To solve the problem, offset boost scheme is adopted to control the basin of attraction and make it touch the origin, which allows to coin the hidden attractor via configuring zero initial value and making it feasible in experimental observation. Finally, the analog circuit-assisted experiment validated the feasibility of the scheme.

A parametrically excited mode-localized accelerometer is designed using the bifurcation phenomenon to improve the robustness of the fluctuation of the driving voltage and damping while maintaining high sensitivity. A dynamic multi-physics model was established while considering both mechanical and electrostatic nonlinearities. The equation was solved by method of multiple scales and verified by harmonic balanced method coupled with the asymptotic numerical method. Two types of bifurcation exist in amplitude frequency response, namely Saddle-Node bifurcation and Supercritical Hopf bifurcation. By introducing Saddle-Node bifurcation, the response amplitude and measurement range can be improved by 100% and 1000%, respectively, while the sensitivity of the amplitude ratio is about 2 orders of magnitude higher than that based on the frequency ratio. At the Supercritical Hopf bifurcation point, a small acceleration will change the topological structure from Supercritical Hopf to Saddle-Node bifurcation. The variation in the amplitude ratio of the Supercritical Hopf point with acceleration is similar to the sign function, which leads to an extremely high sensitivity of 10000%/g in a dynamic range of ±0.001 g. Moreover, the Supercritical Hopf bifurcation point is not affected by the amplitude of the excitation voltage and damping coefficient, which provides a new method for improving the sensing robustness. Ethical Compliance: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Conflict of Interest declaration: The authors declare that they have NO affiliations with or involvement in any organization or entity with any financial interest in the subject matter or materials discussed in this manuscript.

In this work, we use the enhanced modified extended tanh method (eMETEM) and the unified Riccati equation expansion (UREEM) to find analytical solutions to the Drinfeld-Sokolov-Satsuma-Hirota equation (DSSH). The use of coupled nonlinear partial differential equations in the modeling of many physical phenomena, the origin of the Drinfeld-Sokolov-Satsuma-Hirota equation being the formation of the coupled system, and the fact that this model also constitutes a fundamental model in representing numerous physical events, primarily shallow water and coastal regions, have been the driving force behind the study. To visualize the obtained solutions, contour, two and three-dimensional plots are presented. The proposed methods have effectively generated a range of solitons, such as kink, singular, and periodic singular types. The graphic presentations complete the interpretation of the physical significance of the obtained kink and singular soliton types, and the interpretation of the obtained graphs within this framework. In this sense, the findings of the study will help to shape future research in this field.

In the field of macromolecular chemistry, handcuff-shaped catenanes and pretzelanes have a conformation consisting of two distinct loops and an edge connecting them. In spatial graph theory, this shape is referred to as a handcuff graph. One topological aspect of interest in these molecular structures involves determining the minimal number of monomers required to create them. In this paper, we focus on a handcuff graph situated in the cubic lattice, which we refer to as a lattice handcuff graph. We explicitly verify that constructing a lattice handcuff graph requires at least 14 lattice sticks, except for the two handcuff graphs: the trivial handcuff graph and the Hopf-linked handcuff graph. Mainly we employ the properly leveled lattice conformation argument, which was developed by the authors to find the lattice stick number of knot-shaped and link-shaped molecules.

The subject of this article is to study a memristive system and modulation and demodulate the information signal in security system, a novel memristive system is presented and its dynamics are considered. Then, the adaptive synchronization control between the proposed memristive systems is demonstrated. Additionally, the original signal is modulated in a system parameter and it can be demodulated by using filter technology. Compared to previous secure systems, in this scheme, the demodulated signal can be adjusted by the adaptive filter, It has better security performance and is easy to implement in engineering.

In the present work, we aim to explore the new (3+1)-dimensional integrable fourth-order nonlinear equation(IFNE) for describing the shallow water waves. First, we study its N-soliton solutions via the bilinear form which is constructed by applying the Cole-Hopf transform. The resonance conditions of the soliton molecular are extracted and the soliton molecules are obtained. Second, the ansatz function method together with the symbolic computation, is implemented to develop the interaction wave solutions(IWSs). Finally, we take advantage of the Bernoulli sub-equation function method(BSFM) to look into the travelling wave solutions(TWSs). Different kinds of the TWSs like the singular-kink and kink solitary wave solutions are found. Correspondingly, the dynamic performances of the solutions are depicted graphically to present the physical interpretations. And for all we know, the solutions got in this work are all new and can be regarded as an extension of the solutions for the new (3+1) dimensional IFNE, which are expected to have practical significance for the application of these equations in physics.

Monte Carlo (MC) methods are increasingly recognized as severe in many computational scientific fields and have diverse applications in many branches of science. This paper systematically provides two computational algorithms based on MC methods to solve different forms of Lane-Emden (LE) type equations. The proposed algorithms introduce solutions to 11 LE equations under various complex conditions. The performance and comparative study of numerical solutions based on the MC algorithms were computationally analyzed using other numerical/analytical methods available in the literature. We find that the MC solutions agree with the exact or Runge–Kutta solutions and different numerical methods applied to solve these equations.

The combined impact of radiation and convection on the heat transfer of a wavy fin is scrutinized in the present analysis. The novelty of this research work is that it proposes a deterministic machine learning model known as an extreme learning machine to address the heat transfer problem of a wavy fin. The effect of radiation on convective heat transfer and the Rosseland approximation for the radiation heat exchange have been considered in the investigation. The nonlinear ordinary differential equation (ODE) is converted to its nondimensional form using the appropriate dimensionless variables. Runge-Kutta-Fehlberg's fourth-fifth order technique (RKF 45) is used to solve the nondimensional ODE numerically. The roles of convection-conduction, radiation-conduction, thermal conductivity, and radiation parameters have been discussed for satisfying a prescribed temperature distribution in rectangular and wavy fins with graphical visualization. A rise in convection-conduction and radiation-conduction variables decreased the thermal distribution of both the wavy fin and rectangular fin. Further, ANSYS simulation analyzes the variation of temperature and total heat flux in both rectangular and wavy fins. The study demonstrates the effectiveness of the model selected through the obtained results, which indicate the potential of the regression model for providing an accurate prediction.

This research work is devoted to undertake a mathematical model for emissions of carbon dioxide (CO₂) from energy sector using the concept of fractals-fractional differential (FFD) operator. Here, it should be kept in mind that as the population is expanding, so the need of energy increasing day by day. Burning fossil fuels accounts for a sizable amount of the world's energy production, which increases the concentration of CO₂ in the atmosphere and causes the global warming. It's critical to reduce CO₂ emissions from the energy industry. Therefore, via the use of FFD operator, we investigate a mathematical model which is addressing the mentioned process. We deduce some qualitative results regarding the existence of such models in real life using mathematical analysis. The aforesaid analysis is based on some fixed points approaches. Additionally, some analysis devoted to stability is also derived for the proposed model. In addition, a numerical algorithms based on modified Euler method is constructed to simulate the results graphically.

The nonlinear Chen-Lee-Liu (CLL) equation is an important mathematical model that is employed in the evaluation of optical fiber communication systems. It considers several factors such as noise, dispersion, and nonlinearity that might affect the signal quality and data transmission rates in optical fiber networks. The design of optical fiber systems may be optimized by using the CLL model. In this paper, we have examined adequate soliton solutions that can be applied to the optics of the CLL model with a beta derivative utilizing the auxiliary equation and advanced generalized $\left({G\text{'}}/G\right)$-expansion approaches. The bell-shaped, periodic, and other soliton-like properties are displayed in the numerical simulations of the resultant solutions and the necessary forms demonstrated the structure, propagation, and impact of the fractional parameter. The findings of this study show that the applied methodologies are dependable, effective, and competent to create optical soliton solutions for additional complex wave equations in optical fiber communication.

In this paper, we investigate the degenerate behaviors and decompositions of two-soliton solution on the non-vanishing constant background for the (1+1)-dimensional Ito equation. By tuning the background constant, interaction phenomena of various types such as the elastic interaction of solitons, fission or fusion phenomena are presented. The degenerate two-soliton solutions which lead to a higher amplitude soliton in collisions of two solitons or describe the decay of a soliton into two new solitons are obtained. To better understand the nature of these interaction phenomena, we explore different decompositions to express the two-soliton solution as a sum of two functions. One of the function exhibits a special soliton excited by the collisions of two solitons, and the other describes the energy exchange of two solitons. Finally, under the module resonance of wave numbers, other types of the degenerate solutions of two solitons are derived and analyzed, such as the breather and rogue wave solutions.

The significance of safeguarding the security of image information has escalated significantly, owing to the exponential proliferation of digital images containing sensitive information being disseminated on the Internet. In this paper, we first propose a novel 4D hyperchaotic system and design a new image encryption algorithm in conjunction with the hyperchaotic system. The algorithm uses a split random swap permutation method to permute the image and combines the S-box to diffuse the image. To improve the diffusivity of this encryption algorithm, a cross-random diffusion method is designed to diffuse the image again. Then, we propose a region of interest (ROI) encryption scheme for images. This scheme can automatically identify irregular privacy targets in images and encrypt them. To ensure the security of the region of interest location information during transmission, the scheme compresses the location information of the privacy target using a run-length encoding technique and then embeds the compressed data into the ciphertext image using reversible steganography based on histogram shift. The experimental results and security analysis unequivocally demonstrate that the image encryption algorithm proposed in this paper exhibits robust resistance against a wide array of attacks, thereby ensuring a high level of security. Additionally, the devised image ROI encryption scheme effectively safeguards diverse privacy targets.

The non-degenerate hyperchaotic systems with the maximum number of positive Lyapunov exponents (LEs) typically have better ergodicity, pseudo randomness, and stronger anti-degeneration property. Therefore, designing non-degenerate hyperchaotic maps with complex dynamics has attracted increasing attention from various research fields in recent years. By introducing the sine function, this paper proposes a construction model of N-dimensional non-degenerate discrete hyperchaotic map. To verify the effectiveness of this model, we provide three sub-maps of different dimensions based on this model as illustrative examples, and the dynamic behavior is explored using multiple numerical measures. The results demonstrate that the sub-maps with concise symmetric structures have complex dynamics, such as ultra-wide non-degenerate hyperchaotic parameter range, state transition phenomenon, and multistability. In particular, coexisting symmetric attractors and quasi-periodic curves switch periodically with the change of initial value. Furthermore, the hyperchaotic sequences generated by the three sub-maps have excellent performance, and the NIST test also further verifies the super randomness and unpredictability of these sequences. Finally, through the DSP hardware platform, the physical realizability of the sub-maps is verified successfully.

In this paper, a memristor-based neural network is proposed, which is implemented by two tri-neuron resistive-cyclic Hopfield neural networks (RC-HNNs) via memristive bridging. The memristor-bridged network has a line equilibrium set composed of infinitely many index-2 saddle-foci, but it can produce multi-scroll chaotic attractors contrary to Shil'nikov's criterion. Complex bifurcation behaviors, scroll-growing chaotic attractors over time, and homogeneous coexisting attractors are revealed by numerical methods. Further, a scroll-control scheme is designed and scroll-controlling chaotic attractors are demonstrated numerically. The results show that the memristor-bridged network can not only generate scroll-growing chaotic attractors over time, but also produce scroll-controlling chaotic attractors by limiting the dynamic range of the internal state of the bridging memristor. Finally, an analog electronic circuit is designed for the memristor-bridged network, and PSIM circuit simulations are used to verify the numerical simulations.

This study aims to investigate the maximum energy absorption of sandwich panels featuring composite facesheets and a polyurethane foam core under low-velocity impact. The research explores various impactor head geometries, fiber orientations, and the number of composite layers on the panel facesheets. Three different impactor heads with flat, hemispherical, and conical shapes were used for experimental impacts. Numerical simulations were performed using Abaqus/Explicit finite element software, with damage initiation in the composite layers determined by the three-dimensional Hashin criterion. The results revealed that the conical-head impactor caused the highest energy absorption, accompanied by the greatest displacement and velocity changes. Among specimens with different fiber orientations, the 60° fiber layers exhibited a 9.41% and 8.45% higher maximum force compared to the 30° and 45° fiber layers, respectively. Furthermore, the study investigated the influence of the number of composite layers in the facesheets. It was found that panels with more layers in the bottom facesheet demonstrated a 4.94% increase in energy absorption compared to panels with more layers in the top facesheet. This research provides valuable insights into optimizing sandwich panel designs for enhanced energy absorption during low-velocity impact scenarios.

The distributed order fractional derivatives can describe complex dynamic systems. In this paper, considering the periodic pressure gradient and magnetic field, the time distributed order fractional governing equations are established to simulate the two-dimensional flow and heat transfer of viscoelastic fluid between coaxial cylinders. Numerical solutions are obtained by the L1 approximation for the Caputo derivative (L1-scheme) and the finite difference method, and the effectiveness of numerical method is verified by a numerical example. Results demonstrate that the time distributed fractional Maxwell model can promote the flow while the distributed Cattaneo model can weaken heat transfer than the fractional Maxwell and Cattaneo model, and different weight coefficients have different effects on the fluid. The effect of physical parameters, such as the relaxation time of velocity and temperature λ₁, λ₂, the magnetic parameter M, the amplitude P₀ and frequency w of pressure gradient, and the Prandtl number Pr on velocity and temperature are discussed and analysed in detail.

In this current, the applications of the Yang transformation technique are taken under consideration to deal with the non-linear fractional Navier–Stokes equation and fractional coupled Navier–Stokes equation. The suggested method produces approximate-analytical solutions in the form of a series that are correspondingly dependent on fractional-order derivative values and have modest, comprehensible mechanics and easy implementation. The Caputo fractional derivative is employed, and the numerical scheme's stability and convergence are examined. Numerical examples demonstrate the analytical solution of the technique and it is examined that the proposed techniques are robust, efficient and reduce the number of numerical computations. The current technique's results are compatible with the theoretical analysis, and the suggested technique can be extended to solve numerous higher-order non-linear dynamics.

We show that the ordinary differential equations (ODEs) of any deterministic autonomous dynamical system with continuous and bounded rate-field components can be embedded into a quadratic Lotka-Volterra-like form by turning to an augmented set of state variables. The key step consists in expressing the rate equations by employing the Universal Approximation procedure (borrowed from the machine learning context) with logistic sigmoid 'activation function'. Then, by applying already established methods, the resulting ODEs are first converted into a multivariate polynomial form (also known as generalized Lotka-Volterra), and finally into the quadratic structure. Although the final system of ODEs has a dimension virtually infinite, the feasibility of such a universal embedding opens to speculations and calls for an interpretation at the physical level.

This paper exposes the theoretical and microcontroller implementation probing of the piecewise nonlinear resistor-capacitor shunted Josephson junction circuit (PNRCSJJC). The PNRCSJJC is characterized by no steady state when the applied current is greater than one and exhibits two steady states in which one is a focus and its counterpart a saddle-node for excitation current less than or equal to one with credit to the Routh–Hurwitz criterion. The PNRCSJJC exhibits periodic characteristics, quasi-periodic characteristics, varying structures of chaotic characteristics, and coexisting behaviors which is proved qualitatively by the microcontroller execution method. The polarity of the chaotic signal in the voltage state variable is flexibly altered by varying a constant parameter included in the rate equations of PNRCSJJC.

We derive the Jacobi last multiplier for second-order ordinary differential equations of the Levinson–Smith type by using a combination of previous techniques employed for the Liénard-I and II classes of equations. This opens up the possibility for a Lagrangian or Hamiltonian description of the systems governed by the Levinson–Smith type of equations as well as simplifying the problem of finding first integrals of motion. The procedure has been illustrated by a number of suitable examples alongwith Kamke's equation with explicit time dependent coefficients.

In this paper, under the assumption of unstable almost product property for C¹-smooth partially hyperbolic diffeomorphisms, we establish variational principles for their unstable Bowen topological pressures and unstable packing topological pressures on the typical saturated subsets G_K, where K is a given non-empty compact connected set of invariant measures. Actually, we show that these two dimension-like topological quantities coincide with the infimum and supremum respectively of the summation of unstable metric entropy and Lyapunov exponent, where the infimum and supremum are taken over all measures inside K. Besides, we also show that G_K has full unstable topological capacity pressure for reasonable sub-additive potentials.

In this paper, we investigate a fractional parabolic-elliptic chemotaxis-Navier–Stokes system in spatial dimensions three and obtain the global existence of the suitable weak solution by a contraction mapping theorem. Furthermore, we improve the regularity of the solution through a local maximal L^p regularity estimate for the fractional heat equation such that the suitable weak solution is smooth away from a closed set whose one-dimensional parabolic Hausdorff measure is zero, which extends the partial regularity theory of Caffarelli, Kohn and Nirenberg [10] on the Navier–Stokes equation to the fractional parabolic-elliptic chemotaxis-Navier–Stokes system.

As neural networks are easy to converge to local minimum, the ergodicity of chaotic system is helpful to tackle this problem. Besides, the real parts and imaginary parts in complex-valued chaotic systems are independent, which increase the ergodic property and unpredictability of the chaotic signals. Therefore, we propose a new chaotic neural network with complex-valued weight for electrocardiogram classification. Firstly, a complex Logistic chaotic map is put forward, and its bifurcation diagram, Lyapunov index, and chaotic attractors are analyzed. Secondly, based on the ergodicity of complex Logistic chaotic map and a novel neuron function, the learning algorithm including complex-valued weight iteration for the chaotic neural network is proposed. Finally, the MIT-BIH data-base is used to verify the proposed method. The chaotic neural network with real Logistic map and other classification methods are also adopted for comparison. The results show that our chaotic neural network has a certain improvement in the accuracy of electrocardiogram classification.

This paper evaluates the microcontroller implementation, offset boosting control, suppression of chaos, and combination of three types of synchronization in the autonomous piecewise damping Josephson junction (JJ) jerk oscillator (APDJJJO). The APDJJJO exhibits vast shapes of chaotic behaviors, bistable limit circles, bistable period-2-oscillation, and the coexistence of regular and chaotic behaviors exposed by numerical simulations. The microcontroller realization scheme of APDJJJO validates simulated dynamics. Proceeding, two constants are outlined in the rate equations of APDJJJO to achieve the linear offset boosting of constants based on the second and third state variables, respectively. The polarity of the chaotic signal of the second or third state variable can be flexibly altered by changing any of the two introduced constants while the other constant is kept at zero. When the two constants are equal, the second and third state variables can swap between bipolar and unipolar signals flexibly by altering the unique constant parameter. Moreover, theoretical probing is performed to validate the efficacy of the configured single controller engrossed in subduing chaos in APDJJJO. Lastly, the combination of three types of synchronization between two chaotic APDJJJO are analytically and numerically investigated.

This paper introduces a novel quartic B-spline collocation method to address the coupled Whitham–Broer–Kaup (WBK) problem. The WBK problem is a topic of interest in the study of nonlinear wave phenomena and has applications in various fields, including fluid dynamics, plasma physics, and nonlinear optics. The method combines spatial quartic B-spline scheme discretization, and Crank–Nicolson temporal discretization. It is unconditionally stable as proven by the Von-Neumann technique. Numerical examples demonstrate the method's superior accuracy compared to existing solutions. Error analysis employs ${l}^{2}$ and ${l}^{\infty }$ norms, while the method exhibits high computational efficiency. The nonlinearity is managed through Rubin-Graves linearization. Comparisons with prior approaches highlight its efficiency, stability, adaptability to complex problems. The quartic B-spline method is well-suited for simulating fluid flow phenomena in shallow water scenarios, offering high accuracy and low computational cost.

Memristor is one of the basic circuit elements commonly used in circuit model analysis. More complex dynamic characteristics can be observed by coupling memristor into nonlinear circuit. However, there is relatively little attention paid to high-dimensional conservative chaos based on memristors up to now. In this paper, a five-dimensional memristor conservative chaotic system is built after the introduction of the memristor into conservative chaotic system. There is no equilibrium point in this system and the phase trajectory produced by it has hidden properties. Its conservatism is analyzed by bifurcation diagram, Lyapunov exponent spectrum and divergence. The phase trajectory will change with the change of parameters, which Poincaré mapping also verified these dynamic behaviors. In addition, hidden extreme multistability and initial value offset boosting behavior are also found in this system. It is to be noted that this behavior is less in memristor conservative chaotic system without equilibrium points. At the same time, a new transient transition behavior is observed. By introducing spectral entropy algorithm, the complexity of sequences is analyzed and compared with the existing literature. The results show that the system has higher complexity. Finally, the systematic analogous circuit is designed and built whose results are consistent with the MATLAB numerical simulation results, which has laid a solid foundation for the practical application of the system in engineering.

The complex differential system can be obtained by introducing complex variable in the real differential system. Complex variables can be decomposed into real component and imaginary component, which makes the complex differential systems have more complex dynamic behaviors. Complex chaotic system is used in secure communications to increase the security of cryptographic systems. In this study, we designed a complex differential system by incorporating a complex variable into a 3D differential system. Dynamics of this complex differential system are investigated by applying typical nonlinear analysis tools. Furthermore, Hamilton energy function for complex differential system is obtained based on Helmholtz's theorem. The values of Hamilton energy with different oscillations of complex differential system are calculated. In addition, offset boosting control for the complex chaotic signal is realized by adding a constant to variable of complex system. Simulation shows that the position of the chaotic attractor in phase space can be flexibly shifted by applying the offset parameter.

Jerk, as a mathematical concept, is used in mechanics to describe the rate of change of acceleration and plays a crucial role in the design of control systems for machines and vehicles. Therefore, it is important to master the various states and the energy released during the change of acceleration. This is why a new simple jerk function introduced afterward, energy released, is derived from a Hamilton function using the Helmholtz theorem. The condition of having a stable or unstable rate of change of acceleration is established using Hopf bifurcation theory. Some two-parameter stability charts are then computed for a suitable selection region of the study. Using some nonlinear analysis metrics, in the unstable region of the study, the occurrence of phenomena is found, such as reverse period doubling bifurcation, antimonotonicity, and hysteresis involving the coexistence of the states in the considered jerk system. An electronic circuit is built and used to implement the mathematical expression of the jerk equation and validate the result of the theoretical investigation.

In most animal and plant cells, the information's processing is insured by calcium ions. This contribution studies the global dynamics of a model of calcium oscillation. From the stability analysis, it is found that the oscillations of that model are self-excited since they are generated from unstable equilibria. Using two-parameter charts, the general behavior of the model is explored. From the hysteresis analysis using bifurcation diagrams with their related Largest Lyapunov Exponent (LLE) graphs, the coexisting oscillation modes are recorded. This phenomenon is characterized by the simultaneous existence of periodic and chaotic oscillations in the considered model by just varying the initial conditions. Using a set of parameters for which the model exhibits multistability, the basins of attraction related to each coexisting solution are computed and enable the capture of any coexisting pattern.

In this article, an autonomous memristive hyperchaotic system with multi-dimensional offset boosting is constructed and analyzed. Besides this, the oscillation can be rescaled by an independent controller in the memristor. Two independent constants are obtained for offset boosting with one or two variables, which provide two modes of offset boosting, including single control and synchronous reverse control. In addition, the offset of the variables is also modified by the system bifurcation parameters or combined with amplitude control. The multistability can also be identified according to the offset boosting. Finally, circuit implementation based on PCB is proposed to confirm the numerical simulations.

The study of fast-slow oscillations in systems with irrational nonlinearity that may yield abundant dynamical mechanisms is not well developed. This paper aims to investigate the fast-slow dynamics in an excited mass-spring oscillator with a pair of irrational nonlinearities, which can undergo the dynamical transition from smooth to discontinuous characteristics depending on the values of a smoothness parameter. Three different types of fast-slow oscillations are reported in this interesting smooth and discontinuous (SD) oscillator with a pair of irrational nonlinearities. Due to the smooth and discontinuous characteristics of this SD oscillator, we consider its dynamical behaviors under the smooth and discontinuous cases, respectively. Based on the fast-slow analysis and the two-parameter bifurcation analysis, the smooth fast-slow dynamics associated with fold hysteresis and its turnover are revealed. In the discontinuous case, the system can be viewed as a piecewise-smooth dynamical system governed by three different subsystems in different regions divided by two nonsmooth boundaries. In particular, the nonsmooth boundaries can be divided into parts with different dynamical behaviors, including escaping and crossing lines. Unlike the smooth case, there is no change in the stability of the equilibrium in these three subsystems. However, transitions of system trajectory induced by crossing lines can account for the generation of fast-slow oscillations in the piecewise-smooth system. As a result, the smooth and piecewise-smooth fast-slow dynamics in the excited SD oscillator with a pair of irrational nonlinearities are revealed, which deepens the understanding of fast-slow dynamics of the dynamical systems with irrational nonlinearity.

The Landau-Ginzburg-Higgs (LGH) equation is a fundamental framework for examining physical systems in the fields of condensed matter physics and field theory. This study delves into the LGH equation, particularly in the context of its relevance to superconductivity and drift cyclotron waves. Researchers have extensively investigated the LGH equation to uncover a diverse array of exact solutions, employing various methodologies. This manuscript centers on the examination of its dynamic properties, encompassing the analysis of phenomena such as bifurcations, sensitivity, chaotic behavior, and the emergence of soliton solutions. To achieve this, we employ the principles of planar dynamical theory, shedding light on the intricate behaviors embedded within the LGH equation. Furthermore, we utilize the tools and techniques provided by planar dynamical theory to derive soliton solutions for the LGH equation.

This paper investigates the occurrence of stochastic resonance in the three-dimensional Hindmarsh-Rose (HR) neural model driven by both multiplicative and additive Gaussian noise. Firstly, the three-dimensional HR neural model is transformed into the one-dimensional Langevin equation of the HR neural model using the adiabatic elimination method, and the effects of HR neural model parameters on the potential function are analyzed. Secondly the Steady-state Probability Density (SPD), the Mean First-Passage Time (MFPT), and the Signal-to-Noise Ratio (SNR) of the HR neural model are derived, based on two-state theory. Then, the effects of different parameters (a, b, c, s), noise intensity, and the signal amplitude on these metrics are analyzed through theoretical simulations, and the behavior of particles in a potential well is used to analyze how to choose the right parameters to achieve high-performance stochastic resonance. Finally, numerical simulations conducted with the fourth-order Runge–Kutta algorithm demonstrate the superiority of the HR neural model over the classical bistable stochastic resonance (CBSR) in terms of performance. The peak SNR of the HR neural model is 0.63 dB higher than that of the CBSR system. Simulation results indicate that the occurrence of stochastic resonance occur happens in HR neural model under different values of parameters. Furthermore, under certain conditions, there is a 'suppress' phenomenon that can be produced by changes in noise, which provides great feasibilities and practical value for engineering application.

In this research paper, we address the time-fractional heat conduction equation in one spatial dimension, subject to nonlocal conditions in the temporal domain. To tackle this challenging problem, we propose a novel numerical approach, the 'Rectified Chebyshev Petrov-Galerkin Procedure,' which extends the classical Petrov-Galerkin method to efficiently handle the fractional temporal derivatives involved. Our method is characterized by several key contributions; We introduce a set of basis functions that inherently satisfy the homogeneous boundary conditions of the problem, simplifying the numerical treatment. Through careful mathematical derivations, we provide explicit expressions for the matrices involved in the Petrov-Galerkin method. These matrices are shown to be efficiently invertible, leading to a computationally tractable scheme. A comprehensive convergence analysis is presented, ensuring the reliability and accuracy of our approach. We demonstrate that our method converges to the true solution as the spatial and temporal discretization parameters are refined. The proposed Rectified Chebyshev Petrov-Galerkin Procedure is found to be robust, and capable of handling a wide range of problems with nonlocal temporal conditions. To illustrate the effectiveness of our method, we provide a series of numerical examples, including comparisons with existing techniques. These examples showcase the superiority of our approach in terms of accuracy and computational efficiency.

Most existing chaotic maps have many defects in engineering applications, such as discontinuous parameter range, uneven output of chaotic sequences and dynamic degradation. Based on this, a generalized n-dimensional polynomial chaotic map is proposed in this paper. By setting the coefficient of the linear term and the order of the highest order term of the polynomial, a series of n-dimensional polynomial chaotic maps of specific Lyapunov exponents can be obtained. The system solves the defects of the above system well, in addition, one can get the desired number of positive Lyapunov exponents, and one can get the desired value of positive Lyapunov exponents. Then, the effectiveness of the map is verified by a specific numerical example, and its dynamic analysis shows that the map has complex dynamic behavior. Finally, the map is applied to secure communication technology. Compared with other chaotic maps of the same dimension, the maps can obtain a smaller bit error rate, indicating that the chaotic map is more suitable for chaotic secure communication applications.

This study delves into the exploration and analysis of the fractional order Drinfeld-Sokolov-Wilson (FDSW) system within the framework of the Caputo operator. To address this complex system, two innovative methods, namely the Aboodh transform iteration method (ATIM) and the Aboodh residual power series method (ARPSM), are introduced and applied. These methods offer efficient computational tools to investigate the FDSW system, particularly in the fractional order context utilizing the Caputo operator. The ATIM and ARPSM are employed to solve and analyze the FDSW system, allowing for the derivation of solutions and insights into the system's behavior and dynamics. The utilization of these novel methods showcases their efficacy in handling the intricate characteristics of the FDSW system under fractional differentiation, offering a deeper understanding of its mathematical properties and behaviors.

The central purpose of this paper is extracting some novel and interesting soliton solutions of the extended (3+1)-dimensional Jimbo-Miwa equation(JME) which acts as an extension of the classic (3+1)-dimensional JME for the plasma and optics. First, we study the N-soltion solutions that is developed by the Hirota bilinear method (HBM). Then, the soliton molecules and Y-type soliton solutions are constructed via imposing the novel resonance conditions to the N-soltion solutions. In addition, we also explore the complex multiple soliton solutions via the HBM. The dynamic properties of the N-soltion, soliton molecules, Y-type soliton as well as the complex multiple soliton solutions are presented graphically. The developed soliton solutions of this research are all new and can enable us apprehend the nonlinear dynamic behaviors of the extended (3+1)-dimensional JME better.

The (3+1)-dimensional Geng equation is an extended version of the KdV model that describes the wave dynamics behavior of shallow water waves in complex applications. In this study, we discuss the (3+1)-dimensional Geng equation using the bilinear neural network method. By incorporating specific activation functions into the neural network model, new test functions are constructed. Using symbolic computational techniques and selecting appropriate parameters, we systematically obtain new meaningful exact solutions of some (3+1)-dimensional Geng equations, including dark lump solutions, three kinds of interaction solutions, and bright and dark soliton solutions. Furthermore, the results are visualized through diagrams of different categories, which intuitively demonstrate the evolution process and physical characteristics of the waves.

The present manuscript describes a comprehensive characterization of a novel highly segmented 5 mm CZT sensor attached to Timepix3. First, the sensor's IV curve was measured and basic sensor characterization was done with laboratory γ-radiation sources. The sensor resistivity was determined to be (0.155± 0.02) GOhm · cm. The sensor showed decent homogeneity, both for the per-pixel count rate and electron mobility-lifetime product μ_eτ_e. The latter was measured to be $\overline{{\mu }_{{\rm{e}}}{\tau }_{{\rm{e}}}}$ = 1.3 × 10⁻³ cm²/V with a standard deviation σ = 0.4 × 10⁻³ cm²/V describing the dispersion of values for different pixels. The basic sensor characterization is complemented by measurements at grazing angle in a 120 GeV/c at the CERN's Super Proton Synchrotron. The penetrating nature of these particles together with the pixelation of the sensor allows for a determination of the charge collection efficiency (CCE), as well as charge carrier drift properties (drift times, lateral charge cloud expansion) as a function of the interaction depths in the sensor. While CCE drops by 30%–40% towards the cathode side of the sensor, from the drift time dependency on interaction depth, the electron mobility μ_e was extracted to be (944.8 ± 1.3) cm²/V/s and τ_e = (1.38 ± 0.31) μs. The spectroscopic performance was assessed in photon fields and extracted from energy loss spectra measured at different angles in the pion beam. While at photon energies below 120 keV incomplete charge collection leads to an underestimation of the photon energy when irradiated from the front-side, at higher energies the relative energy resolution was found to be ∼4.5%, while a relative energy resolution of ∼7.5% was found for the particle energy loss spectra. It is shown that the drift time information can be used to reconstruct particle interactions in the sensor in 3D, providing a spatial resolution of σ_xyz = 241 μm within the sensor volume and a particle trajectory measurement precision Δ_xyz = 100 μm, at a distance of 1 m from the sensor. We demonstrate by measurement with a ²²Na source, that the energy resolution combined with the 3D reconstruction allows for detection of γ-ray source location and polarity using Compton scattering within the sensor (Compton camera and scatter polarimeter).

The nuclear level density parameter (NLDP) plays an important and crucial role in the most widely used phenomenological models that calculate the nuclear level density (NLD) based on the Fermi gas model (FGM). NLDP can be affected by various effects that have been ignored during the FGM calculations. The dependence of NLDP on excitation energy has been predicted by various references and using various relationships that are mainly tested and normalized at low energies by experimental data of low levels. In this research, using nuclear reaction codes and experimental data of the evaporation spectrum of heavy ion ³²S + ⁷⁴Ge reaction leading to ¹⁰⁶Cd compound nucleus (CN) at high excitation energies, high energy behaviour of NLDP is investigated and compared with different relationship predictions. By calculating and reducing the contribution of non-equilibrium mechanisms, it is suggested that NLDP behaves increasing and then decreasing at high energies (almost Gaussian-like behavior), contrary to the predictions of all conventional energy-dependent NLDP relations.

This paper studies the cosmographic and matter bounce scenario in modified theory. The corresponding field equations are evaluated after considering special corrections of a Hubble parameter. The linear corrections to the Gauss-Bonnet gravity are being taken to analyze the behavior of Hubble and deceleration parameters. We derive dynamical parameters in a very general way to analyze different energy conditions that would lead to understanding the behavior of the equation of state parameters in cosmography. Finally, the removal of the initial singularity is observed to understand the late-time cosmic acceleration.

The effect of the various density distributions on ¹³C + ^12,13C reactions is investigated by using the optical model at energies near and below Coulomb barrier. For this purpose, five different density distributions of the ¹²C and ¹³C nuclei are used to produce the real potential over the double folding model. To make a comprehensive analysis, the fusion cross-sections, S-factor and elastic cross-sections are simultaneously analyzed at astrophysical energies. It is seen that the theoretical results are in good agreement with the experimental data. In this study, the hindrance characteristics of the S-factors for the ¹³C + ^12,13C reactions are also examined at low energies, and hindrance behavior is not observed.

A mapping from the triaxial rotor Hamiltonian to that of the O(6) limit in the interacting boson model (IBM) is established, which is achieved by introducing the symmetry-conserving high-order interactional terms The validity of the proposed mapping scheme is further examined for the cases with γ = 0 and γ = π/6, respectively. It is shown that the rotor model results can be well reproduced in its O(6) image especially for the low-spin states. It thus provides an alternative way to understand the triaxiality in the finite-N systems and additional insight into the O(6) IBM theory.

Fusion cross section for reactions induced by weakly bound nuclei ⁶He, ^6,7Li ^9,11Be and ¹⁰B on targets lying in the mass region 64 ≤ A ≤ 238 have been investigated at around Coulomb barrier energies within the coupled channel formalism. Specifically, the effects of coupling to low-lying excited states of reactants and those arises due to the breakup of projectile have been studied by using Broglia and Winther (BW91), Aage Winther (AW95) and fitted potential (FP) parameterization schemes. Among these the FP scheme is found to be most appropriate in the description of fusion excitation functions of various projectile-target combination. Further, it is observed that in the sub barrier energy region there is an enhancement in the fusion cross section due to coupling to excited states while there occurs fusion suppression at above barrier energies because of the breakup of the projectile.

Transition energies, electric static polarizability, oscillator strengths and state lifetimes of helium-like quantum dots are determined as a function of their shape and size. A configuration interaction approach based on B-spline functions is used. We found that, the oscillator strengths present an extremum around a low value of the dot radius whatever the shape of the confining potential. This extremum is due to the pressure on the energy levels in such a way that for a particular value of the dot radius, the second electron in the excited one-electron state reaches the borders of the confinement potential. The extremum position depends on the impurity charge and the oscillator strength value at this point changes with the potential well shape. As well, the increase of the effective mass involves the shift of the position of the oscillator strength extremum towards weak radius values. The first excited state lifetime globally increases with the dot radius and the reduction of the nuclear charge but presents a shoulder for a certain low value of the dot radius mostly marked for a triangular form of the confining potential.

We investigate the scattering of a wave packet by the Pöschl-Teller potential in momentum representation. The scattering dynamics of the wave packet for a long-time evolution is feasible in this representation. With the wave function in momentum space, we can construct the time-dependent phase space Wigner function. The corresponding density function in coordinate space is then calculated through the Wigner function. The reflectionless wave packet for integer ν and partially reflected for non-integer ν are demonstrated by analyzing the Wigner function.

The third order nonlinear optical susceptibility (TONOS) of an inverted ZnS/CdSe core–shell spherical quantum dot embedded in SiO₂-matrix with or without impurity, and subjected to an external magnetic field is investigated. Within the framework of effective mass approximation and using B-splines basis functions, the energy levels, the dipole matrix elements and the TONOS are computed. The dielectric mismatch in the interface dots as well as the effective mass dependence on the core and shell regions are taken into account. It is revealed that, simultaneously the shell size, magnetic field and off-center displacement have a noticeable effect on the positions and the heights of the peaks of the TONOS. Moreover, we have shown that, due to the magnetic field and the off-center displacement effects, the TONOS takes different profiles associated with the polarization direction (parallel and perpendicular). In the perpendicular polarization, two peaks of the nonlinear optical properties appear for each off-center displacement value corresponding to the two transversal allowed transitions. The shift towards higher energies of the peak position and the reduction of the intensity of the peak when the magnetic field increases are recorded in the transversal transition case. Furthermore, in the longitudinal transition, as increasing the magnetic field strength, the intensity of the peak of the TONOS grows and the position of the peak is shifted towards lower frequencies. The dielectric constant, effective mass and conduction band offset of the materials that constitute the core and shell are equally found to modify significantly the main features of the susceptibility.

We have calculated the differential cross sections for the elastic, excitation to H(n = 2), and electron-transfer processes in He⁺ + H collision using a semiclassical atomic-orbital close-coupling method within two-electron treatment. The calculations have been implemented with four different basis sets to see the effects of electron-exchange, electron-transfer channels, and continuum channels. The results are compared with those of experiments and other calculations.

In order to achieve precise and controllable cutting of graphene and to meet the high quality of cutting edges required in electronics. In this study, the tangential force, radial distribution function, dangling bonds, oxidation bonds, and density functional theory were used to investigate the mechanical behaviour, cutting damage, microscopic mechanism of chemical reactions, and feasibility of elementary reactions in mechanical chemical nano cutting graphene with different solution environments. The results show that the difference in the number of broken and interfacial bonds, dominated by the variability of chemical interactions, leads to a difference in cutting forces, and that there is a negative correlation between the number of C–C bonds and the number of C–O bonds. In the pure H₂O solution environment, the unsaturated C atoms in the carbon chain undergo adsorption reactions with the solution atoms, which shows the carbon chain structures such as –C^#–H₂O, –C^#–H, –C^#–O and –C^#–O. In the ·OH solution environment, the edge structure atoms obtained by mechanical chemical nano cutting of graphene are more structured, more C–O interfacial bonds are formed, and the C atoms are able to detach from the graphene in the form of C*O₂. The energy barriers in the elementary reactions need to be overcome by the mechanical action of the probe, and the cooperative roles of mechanical behaviour and chemical reaction enables oxidation and smooth cutting of atoms at the slit edges of graphene.

This paper presents a thorough analysis on analog/RF parameters including interface trap charges (ITCs) of two different densities of states (DOS) along with self-heating on the performance of DMG FinFETs in Overlap and Underlap configurations. Initially, the independent simulations for acceptor ITCs and Self-heating in conventional device reveals that performance degradation caused by Self-heating is more prominent (25.03%) than uniform acceptor ITCs (9.46%). In consecutive step, the cumulative impact of both acceptor ITCs and Self-heating on DC and RF/analog parameters are carried out. Investigation reveals that as the impact of self-heating is larger in overlap configuration, the degradation in drain current is higher in overlap configuration (45.2%, 54.5%) as compared to conventional (30.4%, 40.96%) and underlap (37.2%, 52.8%) configurations for both Uniform and Gaussian trap distributions, respectively.

This paper investigates the comparative feature of Graphene Source Single Material Gate Vertical Tunnel FET (SMG-GR-VTFET) and Graphene Source Double Material Gate VTFET (DMG-GR-VTFET) on DC, analog/RF and linearity applications using Sentaurus TCAD simulator. The results show that both devices outperforms in DC characteristics, including ambipolar current, subthreshold swing (SS), I_ON/I_OFF ratio etc The study focuses on important figures of merit (FOMs) such as transconductance (g_m), output conductance (g_d), cut-off frequency (f_t), second-order transconductance (g_m2), third-order transconductance (g_m3), VIP2, and VIP3, which are all improved due to high mobility of graphene leads to improved band-to-band tunneling. The observed I_ON is 5.2 × 10⁻⁴ (1.1 × 10⁻³ A/μm), I_OFF is 1.439 × 10⁻¹³ (2.28 × 10⁻¹⁶A/μm) and I_ON/I_OFF ratio of 3.613 × 10⁹ (4.824 × 10¹²) for SMG-GR-VTFET (DMG-GR-VTFET), respectively. It is seen that maximum g_m is 2.96 × 10⁻³ (2.59 × 10⁻³ S μm⁻¹) and cut-off frequency (f_t) values of 1.1 × 10¹¹ (1.85 × 10¹¹ Hz) for SMG-GR-VTFET (DMG-GR-VTFET), respectively. Regarding the Linearity parameter VIP2 value is 2.71 V (0.99 V), respectively, for SMG-GR-VTFET (DMG-GR-VTFET). These results suggest that Graphene Source Vertical Tunnel FET is an excellent choice for analog and high-frequency applications.

This paper presents a polarization-insensitive rasorber implemented with absorption-transmission-absorption (ATA) characteristics over three consecutive frequency ranges in the terahertz (THz) band. The proposed rasorber is made of a two-layer periodic structure. These two layers are separated by a spacer made of glass substrate. The unit cells of the top layer have a modified swastika geometry metallization, which is loaded with graphene strips to make it lossy and provide dual-band absorption. In the bottom plane frequency selective surface (FSS), a square ring is engraved on the metal layer to obtain bandpass characteristics between two stopbands provided by the top layer. The designed rasorber works in the $0.2\mbox{--}1.2$ THz frequency range. It provides wideband absorption with a $\left|{S}_{11}\right|\lt -10\,{\rm{dB}}$ from $0.274$ to $1.094$ THz with a fractional bandwidth (BW) of around $118 \% .$ An in-band transmission window is designed with a $\left|{S}_{21}\right|\gt -3\,{\rm{dB}}$ in the frequency of $0.615$ to $0.719$ THz provides a large BW of $104$ GHz ($15.59 \%$) for THz communication. Within this transmission band, the lowest insertion loss of $0.27\,{\rm{dB}}$ is obtained at 0.686 THz. It provides the absorption of more than $80 \%$ in both the lower band ($0.276\mbox{--}0.442$ THz, $46.24 \%$ BW) and the higher band ($0.861\mbox{--}1.094$ THz, $23.83 \%$ BW). The simulated response of the designed rasorber using a full-wave electromagnetic simulator and calculated through ECM are found to be in good agreement.

THz hook (TH) is a curved beam in THz frequency region, which is characterized additionally by the bending angle θ besides focal length, intensity and transverse size. Here, we study paired THs generated by two cuboid scatterers placed on a hollow mirror. The study focuses on the effects of hollow geometry and polarization state of incident wave on the THs performance. The results show that the hollow geometry affects mainly the bending angle θ, which can change by two fold. The effect is associated with the hollow geometry induced changes of number and position of phase singularity in Poynting vector distribution. The polarization state of incident wave affects considerably both bending angle and focal length. As the polarization state is changed, the FL (focal length) can change by ∼26 fold and the θ by ∼9° due to the interactions of the polarized electric field with scatterers and with the hollow mirror. It implies that the use of hollow mirror results in significant enhancement of polarization effect on the TH performance. Present study allows to conclude that the bending angle and focal length of paired THs generated on the basis of the hollow mirror can be efficiently tailored by the hollow geometry and polarization state.

The resolution and imaging quality of ghost imaging is determined by the longitudinal spatial coherence (LSC) of speckle beams on the signal and reference arms. Based on the cross-correlation function, long-exposure and short-exposure computational ghost imaging through turbulent atmosphere is investigated analytically and numerically in the framework of the traditional imaging theory. According to the point spread function (PSF), the modulation transfer function (MTF) is derived, both of which are utilized to evaluate imaging resolution and imaging quality of computational ghost imaging (CGI), respectively. By simulating long-exposure and short-exposure ghost imaging through atmospheric turbulence, the comprehensive effects of atmospheric turbulence and beam initial parameters on the complex degree of coherence (CDC), PSF, and MTF are studied, respectively. It is found that the degradation of LSC between the two planes on the reference and signal path implies a narrower PSF and increased MTF values, which represent the better resolution and imaging quality. Thus, reducing the atmospheric turbulence strength, the speckle particle size, the wavelength and the propagation distance, and increasing the source size contribute to improving resolution and image quality of CGI because of the degradation of LSC. Furthermore, short-exposure CGI can provide imaging performance superior to long-exposure CGI in terms of resolution and imaging quality due to the decrease of LSC.

In this work, an overview of a reference spectral database for diverse organic molecules often used in a chemistry laboratory is shown. Obtained typical Raman signals have been well-resolved within a range from 0 to 3250 cm⁻¹ by using a Coupled-Optical Fiber Raman Spectrograph, COFRS, performing with a sample holder for liquids connected to optical fiber in its typical configuration and an excitation wavelength of 785 ηm. This optical device works by using some spectral acquisition parameters, as integration time, signal average, boxcar or signal smoothing, detector gain and laser variable output power. These last parameter was varied in each compound due to the different purity presented for each organic molecule, and so a higher Raman signal can be obtained. We have included some of the most typical organic molecules used. Further, the main idea is to show a Raman spectral collection for rapid molecular identification of the diverse functional groups related to organic molecules.

MXene, a group of 2D materials, has garnered significant attention from researchers due to its impressive characteristics, such as large surface area, high metallic conductivity, and strong nonlinear saturable absorption. These properties make MXene an excellent material for exploring new possibilities in ultrafast photonics technology. The present study has demonstrated that vanadium carbide (V₂C) MXene can function as a saturable absorber (SA) and effectively generate Q-switching pulses in the 1.9 μm wavelength region. The molten salt synthesis method was used to synthesize V₂C MXene, which involved the selective etching of aluminum (Al) layers from the V₂AlC MAX Phase precursor. The V₂C MXene was transformed into a thin film by mixing it with polyvinyl alcohol (PVA) using a solution casting technique. The resulting V₂C-PVA film was found to have saturable absorption properties, with a modulation depth of 8% and saturation intensity of 1.6 MW cm ⁻². Upon integrating the V₂C-PVA film into the Thulium/Holmium-doped fiber laser (THDFL) cavity, stable Q-switching pulses were realized at a central wavelength of 1896.9 nm with 13.9 nm of 3-dB spectral bandwidth. At the maximum pump power of 448.7 mW, the 2.2 μs of pulse duration, 58.26 kHz of repetition rate, and 31 nJ of pulse energy were achieved. By adjusting the tunable bandpass filter (TBPF) integrated within the THDFL cavity, the system has a tunable spectral range of approximately 120.75 nm, from 1889.75 nm to 2010.5 nm. The exceptional performance of V₂C-based SA for Q-switching operation showcases the immense potential of other MXene materials in the future of photonics applications.

In this article, we have derived the acoustic pressure and medium refractive index expressions in a homogeneous atmospheric medium perturbed by a planar finite amplitude acoustic wave. In a planar finite amplitude acoustic wave perturbation, we developed a Laguerre–Gaussian vortex beam transmission model in a homogeneous atmospheric medium. We investigated the effects of different acoustic source parameters on the phase of the Laguerre–Gaussian vortex beam transmission, considering the atmospheric medium's viscous effect. The results show that acoustic waves of finite amplitude distort the refractive index distribution of a homogeneous atmospheric medium. At a given distance, the amplitude of the refractive index gradually increases with increasing acoustic wave transmission distance. At the same time, the phase of the Laguerre–Gaussian vortex beam is rotated by the perturbation of the finite-amplitude acoustic wave, and the phase always returns to its initial position. Unlike linear acoustic waves, changes in the homogeneous atmospheric refractive index distribution and the homogeneous phase of the Laguerre–Gaussian vortex light no longer satisfy the periodic variation when perturbed by finite-amplitude acoustic waves. Under the same conditions, the effect of finite-amplitude acoustic waves on the phase of the Laguerre–Gaussian vortex light is stronger than that of linear acoustic waves. Finally, the effects of different acoustic pressure and frequency of the source on the phase of the Laguerre–Gaussian vortex beam transmission are calculated. The results show that different acoustic parameters at the source can be used to achieve phase modulation at different distances and intensities.

This paper establishes an evolution model for the spiral phase spectrum of a composite power Gaussian (CPG) vortex beam in plasma sheath turbulence (PST) based on the Rytov approximation theory and the modified von Karman spectrum. The impact of various parameters, including turbulence and beam attributes, on the spiral phase spectrum of the CPG vortex beam in PST is investigated through numerical simulations. Our numerical results reveal that the spiral phase spectrum of beam exhibits asymmetry which modulated by the structural parameter. Meanwhile, the resistance of the CPG vortex beam against turbulence strengthens as the wavelength increases and the topological charge decreases. The findings also demonstrate that the spiral phase spectrum of the CPG vortex beam incorporates a broader range of modes in isotropic PST compared to anisotropic PST. Furthermore, the impact of PST on the beam is intensified with a higher refractive index undulation variance and a smaller outer scale parameter.

In this paper, an analytical model of eddy current testing of a metal tube has been proposed to evaluate circumferential cracks from the signals of the magnetic field. First, based on Maxwell's equations in time-harmonic form, magnetic vector potential equations for each region of space are built under two different configurations of the bobbin probe and the encircling probe respectively. Next, the magnetic vector potentials are solved by imposing conditions at the interface. Then, series expressions of the radical and axial magnetic induction intensities have been obtained. In addition, based on the proposed modeling, the influences of cracks at different locations on the surface magnetic field have been analyzed. The results have shown that the radial magnetic induction intensity increases while the axial magnetic induction intensity decreases for the internal and external cracks with the same shape and size on the surface of the metal tube. Moreover, the magnetic induction intensity has shown much more sensitive property to external cracks than it has done to internal cracks for the encircling probe. However, for the bobbin probe, the magnetic induction intensity has demonstrated almost the same sensitivity in detection for both internal and external cracks in the metal tube. The researching results have important theoretical and practical significance for understanding the physical process of eddy current testing, optimizing parameters of the experimental system and building the inversion model.

Surface Light Scattering Spectroscopy (SLSS) can characterize the dynamics of an interface between two immiscible fluids by measuring the frequency spectrum of coherent light scattered from thermophysical fluctuations—'ripplons'. In principle, and for many interfaces, SLSS can simultaneously measure surface tension and viscosity, with the potential for higher-order properties, such as surface elasticity and bending moments. Previously, this has been challenging. We describe and present some measurements from an instrument with improvements in optical design, specimen access, vibrational stability, signal-to-noise ratio, electronics, and data processing. Quantitative improvements include total internal reflection at the interface to enhance the typically available signal by a factor of order 40 and optical improvements that minimize adverse effects of sloshing induced by external vibrations. Information retrieval is based on a comprehensive surface response function, an instrument function, which compensates for real geometrical and optical limitations, and processing of almost real-time data to report results and their likely accuracy. Detailed models may be fit to the power spectrum in real time. The raw one-dimensional digitized data stream is archived to allow post-experiment processing. This paper reports a system design and implementation that offers substantial improvements in accuracy, simplicity, ease of use, and cost. The presented data are for systems in regions of low viscosity where the ripplons are underdamped, but the hardware described is more widely applicable.

Optomechanical uncooled infrared (IR) detectors based on the thermal deformation of bi-material micro-cantilever have proved of significant potential in the IR imaging fields. However, compared to other uncooled infrared detectors, the optomechanical type relies on the mechanical deformation of the thermomechanical cantilevers, which compete for space with the absorbers and isolation beams, resulting in limited sensitivity. By integrating a designed metalens, large deformation, high thermal isolation, and high effective fill factor can be achieved simultaneously. Several pixel designs of optomechanical uncooled IR focal plane array (FPA) with designed integrated metalens are evaluated and optimized through numerical simulation. High thermal conversion efficiency $H=0.016$ and thermomechanical sensitivity ${S}_{{\rm{T}}}=0.264$μm K⁻¹ are simultaneously achieved with an inherent noise-equivalent temperature difference(NETD) value of $3.9\,$mK at the preset $60{\mu }{\rm{m}}$× $60{\mu }{\rm{m}}$ pixels. Using Figure of Merit(FOM) as a comprehensive evaluation of NETD and response time, the optimized structure can be improved by up to 40% over the original structure.

Graphene photodetectors based on the photogating effect offer the advantages of high responsivity. However, physical model of these photodetectors which is suitable for circuit design are still missing at present time. This paper aims to develop a physical model of the detector by introducing a 'virtual back-gate' method, which translates incident optical power into the Dirac point voltage of the transfer curve. Additionally, a physical model of the detector is established by combining the 'virtual back-gate' and 'photo-gate'. To investigate the relationship between input optical power and photocurrent, a detector PSPICE model is developed using the gate-controlled current sources realized through the 'virtual back-gate' and 'photo-gate'. A capacitive transimpedance amplifier circuit is employed for simulation verification. The research presented in this paper serves as a valuable reference for the circuit design of two-dimensional material photodetectors based on the photogating effect.

This paper presents the realization of a multifunction anisotropic metasurface capable of operating as both a half-waveplate and a quarter-waveplate in the C, X, and Ku bands. The numerical and experimental results demonstrate the metasurface is able to convert linear and circular polarizations to their respective cross-polarizations, as well as achieve linear-to-circular and circular-to-linear polarization conversions in the microwave frequency regime. Notably, the metasurface maintains high conversion efficiencies for both half-wave and quarter-wave plate operations, even when subjected to variations in the incidence angle. The underlying physical mechanism is elucidated through the analysis of eigen values, surface current distribution and the retrieval of effective physical parameters. The proposed metasurface is useful for communication and polarization manipulation devices due to its simple construction, compact size, angular stability, and multi-functionality.

There is a well-known asymmetry in classical electromagnetism, apparent in Maxwell's equations, that arises from the existence of electric but not magnetic charge. This has motivated numerous experimental searches for magnetic monopoles which have, to date, not been found. To address this asymmetry, the research reported here generalizes these equations to accommodate complex-valued electromagnetic fields, thereby making Maxwell's equations more symmetric. The resulting generalized equations remain consistent with the experimental predictions of the original Maxwell equations, and they are shown to continue to exhibit conservation of charge. The increased symmetry of the complex-valued equations is demonstrated via a duality transformation that is derived and verified here. Importantly, the generalized theory implies that a novel type of magnetic monopoles exists while simultaneously explaining why their detection has eluded previous experimental searches. Further study of the possibility that electromagnetic fields include imaginary-valued components is clearly merited because of the implications it could have for the foundations of classical electrodynamics.

In this paper, a tunable multilayer structure is proposed, which can provide reversible switching between transmission and absorption modes at the terahertz region without reconfiguration. The layered structure consists of graphene, Si, and VO₂ layers. Transfer matrix method is employed to describe the optical properties of the layered structure. The switching phenomenon occurs based on the VO₂ transition from insulator to metal phase by varying temperature. Furthermore, active frequency tuning by graphene chemical potential for thermally switching transmission and absorption with near-perfect intensity is observed. Incidence angular stability for TE and TM is up to $20^\circ$ and $40^\circ ,$ respectively. Finally, the Si layer thickness effect demonstrates that mainly defines the peak number and frequency for both functions. Theoretical implementation confirms the potential usefulness of the proposed configuration in applications such as reversibly tunable smart absorbers, filters, or thermo-optical switches for high-speed optical systems.

One of the significant metrics that has lately emerged as a result of climate change is the Ultraviolet Index (UVI). In this work, the authors established a standardized reference UVI radiometer at NIS, Egypt, and discussed the performance to cover the actual actinic spectrum. Selective commercial UVI radiometers based on the proposed detector's responsivity and spectral mismatch were compared to the standardized reference UVI radiometer. The result indicated that the established detector response covers the entire UV actinic spectrum (280–405 nm). Besides, the standardized reference UVI radiometer has the least spectrum mismatch value with the (CIE) spectral response, according to a comparison between it and the other detectors that have been evaluated. Furthermore, it has the highest occupied area under the CIE spectral response curve, which is about 73.8%, and has about 12% better performance. These findings support to use of the established detector as a reference standard for detecting UVI at the radiometry lab at NIS Egypt.

Millimeter wave (mm-wave) metalens has shown significant progress in recent years. However, the existing works in the literature on the extended depth of focal (EDOF) metalens present limitations for mm-waves. More specifically, the good performance of the EDOF requires a focal length larger than the radius of the metalens, which limits its miniaturization applications. In this work, mm-wave metalens with EDOF on the short focal length was proposed. The focus distribution was equally divided and the spin Hall effect was employed to guarantee the uniform focus intensity. From our analysis, it was demonstrated that the designed metalens can work at mm-wave frequencies and also achieve extended focal depth at half the metalens' radius. The proposed metalens has the unique characteristics of short focal length (The focal diameter ratio is 0.36) with EDOF. Moreover, it can be used in the mm-wave field for short-distance imaging and detection, also the development of high-power metalens applications may be facilitated.

A small-sized quasi-stepped impedance resonator (SIR) based single-band to dual-band reconfigurable bandpass filter is presented in this work. The proposed quasi-SIR filter is modular in nature and can be easily scaled to higher- or lower-frequency bands. To this end, a single- to dual-band reconfigurable modified SIR is designed. The designed reconfigurable resonator was then used to develop a single-band to dual-band reconfigurable filter. The proposed filter structure comprises two resonators loaded with PIN diodes to provide the switching. The filter allows switching between single and dual-band frequencies. In the OFF state, PIN diodes provide single-band resonance with a resonant frequency of 3.8 GHz. While the ON state of PIN diodes provides dual-band resonance of 3.35 GHz and 4.3 GHz. The structure of the filter is modular and is designed, analysed, and fabricated on a low-cost FR4 dielectric substrate with a 4.3 dielectric constant and 0.78 mm thickness. The measured results are in good agreement with the simulation results. The filter is designed to operate in the sub-6 GHz band, a designated band for 5G communication, and is thus suitable for incorporation in 5G devices with reconfigurability applications.

Transparent solar thermo-photovoltaic (TPV) technology combines visible transparency and solar energy conversion. They are developed for their potential applications in buildings and vehicles windows, where conventional opaque solar cells may not be feasible. TPV's offer a promising solution to harness solar energy without compromising aesthetics or functionality of transparent surfaces. Broadband absorption at UV and IR frequencies and simultaneous transmission at visible frequencies can be achieved by fabricating metamaterials that employ semi-conducting oxides. In this study, an optically transparent metasurface (OTM) based STPV composed of indium tin oxide (ITO) is introduced as the transparent metal and ZnS as a substrate layer. Our design offers a cost-effective and scalable solution for large-scale fabrication. The designed OTM structure exhibits exceptional absorption capabilities, achieving an absorption rate of up to 99% in the UV region. Additionally, it achieves over 90% absorptivity in the far infrared range and maintains a high average transmittance at visible frequencies. Furthermore, the absorption remains consistently high, exceeding 90%, even when the incident angle is less than 70° for both TE and TM polarization waves. This innovative design holds promise for various applications requiring high-performance transparent metasurface absorbers/emitters. The proposed transparent metasurface based STPV holds great potential for efficient utilization in combined solar/thermal conversion systems.

The focusing and imaging properties of the beam have attracted considerable attention recently. In this work, we generated an autofocusing beam termed a chirped autofocusing beam (CAFB) by using the phase of multiple chirped two-dimensional Airy beams, which has autofocusing and imaging properties. Through simulation analysis and experimental verification, it was found that the CAFB is endowed with multiple degrees of freedom to control the focusing properties of the CAFB. Specially, in the range of negative and weak chirp, the focal length of the CAFB increases with decreasing chirped factor. Moreover, the imaging property of the CAFB can be controlled by a chirp factor, the transverse displacement of the CAFB, and the transverse scale factor of the CAFB. The larger the transverse displacement and transverse scale factor of the beam, the better the image quality. Due to these properties, the CAFB may broaden the potential applications in optical microscopy imaging.

In this study, we consider a nonlinear multicoupled discrete electrical transmission line consisting of several modified Noguchi lines and analyze the dynamics of the effects of dissipative elements on modulated waves. This analysis shows that the dispersion element (C_S) and solution parameter (γ) strongly contribute to the increase in voltage amplitudes and to the modulation of these new rogue waveforms, unlike the dissipative element (G). Using a semi-discrete approximation, we demonstrate that the dynamics of modulated waves in such a dissipative electrical system can be governed by a system of nonlinear Schrödinger equations, the Manakov system, and system parameters. The phenomenon of modulational instability in this dissipative electrical system is studied, and areas of instability are shown. We found that the dissipative element of this system increased and decreased the areas of instability. Under the condition of this Manakov system, we determine the approximate modulated wave solutions that are then used for the dynamic analysis of the effects of dissipative elements when transmitting these new rogue waveforms through this dissipative electrical system. The effects of the parameters of this nonlinear dissipative electrical system, such as dispersive, dissipative, and solution parameters, in the dominant direction of propagation of these new rogue wave signals are presented. Based on these results, we observe that the effects of dissipative elements do exist in this nonlinear dissipative electrical system and that these dissipative elements would also impact the areas of modulational instability, which could gradually disappear in this electrical system.

This study thoroughly examines the collective influence of compositional variation and annealing temperature on the electronic structure of sol–gel derived Ni_xZn_1−xO (x = 0 to 1) thin films annealed at different temperatures (700 ${\rm{^\circ }}$C, 800 ${\rm{^\circ }}$C, and 900 ${\rm{^\circ }}$C) using x-ray photoelectron spectroscopy (XPS) and x-ray absorption spectroscopy. A gradual structural phase transition from hexagonal wurtzite ZnO to cubic rocksalt NiO with increasing Ni concentration was revealed by x-ray diffraction (XRD). Grain growth was observed from scanning electron microscopy with increasing annealing temperature. Photoluminescence measurements indicate the presence of interstitial oxygen when Ni atoms are incorporated in the film. The Ni L_3,2 absorption edge shows an intensity enhancement in the white-line feature with increasing Ni concentration, evidencing the presence of higher oxidation states. Concurring results were observed by XPS where both Ni²⁺ and Ni³⁺ free ion multiplets are present in the Ni 2p core level spectrum for 20% and higher Ni concentration. O K and Zn L_3,2 XAS spectra demonstrated the e_g-t_2g sub-band splitting at higher Ni concentration, triggered by band anti-crossing interaction and crystal field splitting. The extended x-ray absorption fine structure (EXAFS) simulation for the Zn K edge revealed a Zn–Zn/Ni bond length change for 60% Ni concentration. The thermal disorder factor increased up to 40% Ni concentration, and beyond that, it decreased due to stable NiO phase dominance in the alloy composite. Ni K edge EXAFS fitting indicated an insignificant change in the Ni-O and Ni–Ni/Zn bond lengths throughout the range of varying Ni concentrations. The thermal disorder factor increases with increasing annealing temperature, indicating a more disordered lattice. Such investigation is essential where the electronic properties of nanometer-sized materials determine the performance of functional devices. The present work critically elucidates the combined impact of compositional variations and annealing temperatures on electronic structures.

This contribution proposes an interesting analytical method to estimate the side lobe characteristics for the pattern factor of the continuous uniform line source in electromagnetics. The new solutions are observed more precise than the classical analytical estimations. Detailed formulas and results are given in explicit validation of the methodology. In particular, to estimate the first side lobe direction, the error between the new method and the truly accurate one is only −0.08%, whereas for the classical analytical study is about 4.87%.

AC loss has significant impact on the design and safe operation of superconducting power equipment. While there have been numerous simulation studies on AC loss, experimental measurement has proven challenging due to its relatively small magnitude compared to reactive power. In our previous work, a method based on fixed forgetting factor recursive least squares for measuring instantaneous AC loss is proposed. However, its applicability is limited due to the varying characteristics of each parameter in superconductors. This paper introduces four recursive least squares with variable forgetting factor algorithms and measures AC loss in ten different superconducting coils. The accuracy of these algorithms is analysed and compared using the integral method as benchmark. The results demonstrate that the recursive least squares with leverage-based multiple adaptive forgetting factors offers the widest range for AC loss measurements.

This paper proposes a tunable broadband terahertz absorber based on metamaterial graphene. The absorber consists of a monolayer of graphene, a dielectric layer, and a metal reflection backing. By adjusting the applied bias voltage, the unique properties of graphene are utilized to control its Fermi level. Simulation results indicate that the absorber has an absorption rate exceeding 70% between 4.2–4.8 THz, with a maximum absorption rate reaching 99.99%, and a sensitivity of 740 GHz/RIU. Compared to similar studies, this structure has significant advantages in sensitivity. Due to the symmetry of the unit structure, the absorber is insensitive to the incident angle. We applied the absorber to trimethylglycine concentration. Experimental results show that the designed absorber can accurately identify the concentration of trimethylglycine solution, detecting concentrations as low as 0.5%.

In synchronized chaotic lasers based secure key distribution and other encrypted communications, presence of the time delay signature in chaos poses a threat to security. So the transmitter and receiver lasers should preferably be operated in complexity enhanced chaotic regime where the time delay signature is hidden. However, achieving good synchronization in experiments in such regime is challenging. We report experimental demonstration of achieving excellent synchronization between two semiconductor lasers even when both the lasers are operating in complexity enhanced chaotic regime with absolutely no time delay signature present in their output. This chaotic regime is ensured by evaluating the auto correlation function, permutation entropy and spectrum analysis of the time series. As a measure of synchronization, cross-correlation coefficient of 0.923 is achieved between the transmitter and receiver lasers. This results are of immense importance in chaos based secure key distribution and other encrypted communication schemes.

Zero-dimensional (0D) and one-dimensional (1D) mixed heterostructure semiconductors can bring superior electrical and optoelectronic performances due to the synergistic advantages of different dimensionalities. Here, a metal-semiconductor–metal (MSM) ultraviolet (UV) photodetector based on 1D-0D TiO₂/CsPbBr₃ heterostructure semiconductor is constructed, which exhibits excellent photodetection performance. A back-to-back Schottky contact is formed in the MSM (Au/TiO₂/Au) structure due to the large band-energy bending resulted from the abundant surface-states at 1D-TiO₂ surface. Under an applied voltage, a small saturation current flows through the device. Benefiting from the decoration of CsPbBr₃ QDs, the dark current of MSM photodetectors can be further suppressed, and producing the improved on/off ratio (I_light/I_dark), photoresponsivity (R_λ), and detectivity (D*). PL properties study suggested that an energy transfer is occurred between the 0D-CsPbBr₃ and 1D-TiO₂. The TiO₂/CsPbBr₃ heterojunctions are beneficial for photo-induced charge transfer in hetero-interface because of the type-II energy-band alignment, but not non-radiative energy transfer from 0D-CsPbBr₃ to 1D-TiO₂. On the whole, this study depicts a fascinating coupling architecture of mixed-dimensional materials toward implementing low-cost and high-performance optoelectronic devices.

The concept of performing mathematical operations with metasurfaces has been suggested by Silva et al (Science 343, 160 (2014)). However, their proposed structure in implementing any transfer function (corresponding to any mathematical operator) for various input signals faces limitations. To tackle this issue, in this study, four different scenarios are proposed on their metasurface-based structure to generalize in a way that can implement each spatial transfer function. To evaluate the performance of the presented scenarios, seven different transfer functions are simulated to encompass a wide range of mathematical operators in the spatial domain. The implementations are based on the Fourier approach. Simulation results based on the finite element method closely match the desired values. From the results of this study, it can be seen that the third and fourth scenarios provide better accuracy. For example, when the fifth transfer function is performed by the basic structure and the fourth scenario, the normalized root mean square error, decreases from the value of 0.235 to the value of 0.0348, respectively. Furthermore, a tunable structure is achievable using the third scenario to produce different operators on the same structure. The realization of these scenarios is possible by using nanostructure-based metasurfaces.

A numerical study on the multi-bar nested cladding design of chalcogenide glass-based negative curvature hollow-core fiber was carried out to achieve a low-loss light guidance in the mid-infrared spectrum centered at 5.4 μm. Fiber design parameters were systematically optimized, and the effect of the nested bars on the confinement and total loss performance of a five-tubular cladding structure was investigated. An ultra-low transmission loss of 0.112 dB km⁻¹ at 5.4 μm was achieved with As₂Se₃ triple-bar negative curvature fiber while maintaining low bending sensitivity. The design is also suitable for high transmission performance with alternative infrared glasses and can be potentially used for low-loss light guidance in a wide mid-infrared spectrum.

This work proposes and numerically optimises a four terminal mechanically stacked tandem with CuI/CH₃NH₃SnI_3−xBr_x/ZnO:Al/IZO as top subcell and IZO/GaSe/CI(G)S/CIGS-P⁺ as bottom subcell. The standalone optimised subcells exhibited power conversion efficiencies of 27.03% (CH₃NH₃SnI₃ based cell) and 24.42% (CIGS based cell), with the tandem configuration showing a combined power conversion efficiency of 51.45%. Band gap optimisation of the CIGS based solar cell also revealed that its gallium content had to be nullified, which is a favourable outcome considering the high cost of gallium. Furthermore, the tandem device also exhibited excellent quantum efficiency while spanning the UV-Vis-NIR range of photon wavelength absorption, as a result of the CI(G)S based subcell complementing the top CH₃NH₃SnI₃ based subcell.

The degradation of Methylene Blue (MB) dye through treatment with an atmospheric pressure glow discharge plasma is presented in this work. The set-up used in this work has the advantage of being very simple without any gas supply. Plasma was diagnosed using optical emission spectroscopy, and rotational temperature of the hydroxyl radicals was measured. The effects of plasma current, treatment time, polarity and material of the electrodes on degradation of MB dye were studied. Experimental results showed that the degradation of dye increased with plasma current and treatment time. Polarity of the electrodes also have an effect in that the liquid cathode mode has about 14% higher degradation efficiency than liquid anode mode. Interestingly, it was found that anodic dissolution of copper electrode aids in degradation of MB dye by initiating Fenton like reactions involving copper ions, which was absent in the case of stainless steel electrode. After 40 min of treatment, the maximum degradation efficiency and COD removal rate achieved was 77% and 74% respectively, while the degradation yield obtained was 0.32 g.kW^–1.h^–1.

A theoretical investigation is carried out for nonlinear electrostatic Kelvin-Helmholtz (K-H) shock waves in a magnetized electron-positron-ion viscous plasma in the presence of transport equations and non-Maxwellian particles by following the generalized (r, q) distribution function. The propagation of electrostatic K-H modes are studied both in the presence of trapped and free electrons. The nonlinear analysis with inclusion of plasma transport properties (magnetic viscosity and heat conduction) lead to nonlinear electrostatic K-H mode in the form of shock like waves by solving the modified Burgers' equation. The electrostatic K-H shocks are investigated numerically with effect of different plasma parameters such as shear velocity and non-Maxwellian distributed particles. It is observed that the striking features (viz., amplitude and width of dissipative shock through the solution of Burgers' equation) of the K-H mode are significantly modified by the effects of non-thermality of electrons and positrons both at shoulder and tails along with shear velocity due to viscosity. The relevancy of our work to the observations in space (viz., cometary comae and earth's ionosphere), astrophysical (viz., pulsars) and laboratory (viz., solid-high intense laser plasma interaction experiments) plasmas is highlighted.

In the laser wakefield acceleration (LWFA), the dephasing problem is a serious energy-limiting factor, which is caused by the velocity difference between the accelerated electrons and the laser wake wave. To overcome the dephasing problem, we developed a special capillary gas-cell with a density up-ramp along the laser propagation direction and used it for electron acceleration experiments. Our experiments, which were performed with a peak laser power of 15 TW at GIST, show that the electron beam energy was enhanced to 260 MeV compared with 98 MeV from a flat density profile, which is more than two fold by the density up-ramp due to the increase of the dephasing length in the density up-ramp. This is the first experimental demonstration for electron energy enhancement using the density up-ramp in a capillary gas-cell. Two-dimensional particle-in-cell (PIC) simulations were also performed to confirm the effect of the density up-ramp, which shows a good agreement with the experimental results. Compared with a gas jet, the capillary gas-cell can provide a more stable and longer plasma so that the density up-ramp method in the capillary gas-cell may produce high quality electron beams of energy up to GeV range.

In the context of rock fragmentation, the application of high voltage electric pulses results in the transfer of electrical energy onto the surface of the rock material, leading to a rapid electrical breakdown and the formation of a plasma channel. The ionized plasma expands at a fast velocity, generating a shock wave that causes significant damage to the rock's integrity. In this study, we develope a numerical model that couples electrical, thermal, and mechanical forces to simulate the formation of plasma channels within rocks due to high-voltage electric pulses. The model's accuracy is verified through field tests, and the results indicate that the configuration of the high-voltage pulse waveform, electrode spacing, and conductor particles within the rock impact the pathway of plasma channel formation. Prior to the formation of the plasma channel, minimal changes are observed in temperature and stress levels, with the majority of electric pulse energy dedicated to the creation of the plasma channel. Following the establishment of the plasma channel, the application of the electric pulse continues, resulting in notable alterations in temperature and stress levels. When the duration of the action reaches 10⁵ ns, the temperature and stress levels surpass 10⁴ K and 50 MPa, respectively, leading to fracture and extensive damage to the rock. The outcomes derived from the numerical model's calculations can help to facilitate the cross-integration between physics and civil engineering and contribute to a deeper understanding of the rock fragmentation process under high voltage electric pulses.

High voltage direct current (HVDC) circuit breakers play a very crucial role in HVDC transmission systems. Energy dissipation circuit branches are the main part of the HVDC breaker. The volume and size of energy dissipation branches are the bottlenecks of the HVDC breaker, and the existing energy dissipation schemes can not meet the lightweight requirements. In this work, a combined energy dissipation scheme based on gallium indium tin (GaInSn) liquid metal and ZnO resistors is proposed for the energy dissipation branch of a circuit breaker. Firstly, the self-shrinking of GaInSn liquid metal mechanism is analyzed and the energy dissipation characteristics at different stages are investigated. The variation patterns of short circuit current, arc voltage, resistance and other parameters in the process of liquid metal arcing and energy dissipation are obtained. Secondly, the circuit model of liquid metal in arcing and energy dissipation process is established. The equivalent nonlinear time-varying conductance of the arcing process of the liquid metal dissipative element is simulated by combining the volt-ampere characteristic curves of the liquid metal dissipative module. Finally, the topology of energy dissipation circuit branches combined by GaInSn liquid metal and ZnO resistors is proposed. At the same time, the HVDC breaker model combined by a hybrid DC circuit breaker and energy dissipation circuit branches is constructed. The energy dissipation ratio and distribution law of GaInSn liquid metal and ZnO resistors in the composite type of circuit breaker are verified. The composite dissipation improves the overall energy dissipation density of the circuit breaker compared to the conventional ZnO resistors energy dissipation.

The essence of Tsallis q-entropy on the occurrence scattering time (OST) process is derived for a nonextensive plasma. The semiclassical eikonal dissection and the nonextensive q-distribution function are used to derive the OST with variables of projectile energy, scattering angle, electron entropic index, ion entropic index, and impact parameter. Our calculations find that the OST advance in a nonextensive plasma decreases with the entropic index. We have seen that the Tsallis q-entropy on the OST advance grows up fast as the scattering angle increases. We also obtained that the nature of Tsallis q-entropy on the OST advance diminishes in forward scattering direction in a nonextensive plasma. Moreover, the authority of the electron q-entropy is found to be greater than the that of ion q-entropy in the cold electron plasma, i.e., when the electron temperature is lower than the ion temperature. However, if the ion temperature is lower than the electron temperature, the authority of the ion q-entropy is more momentous than that of the electron q-entropy.

The Tokamak plasma start-up is the first process to have a successful Tokamak plasma discharge. Considering the start-up condition, high electric field and neutral density with the absence of flux surfaces an enhanced electron transport to the Plasma-Facing Components (PFC) or the inner vessel wall is expected. Such electron excursion under an applied electric field induces electromagnetic emission, especially in the x-ray region. Such emission is important as it gives vital information about the initial condition of the plasma start-up and the potential for energy loss to the PFC/vessel walls. A Silicon Drift Detector (SDD) based soft x-ray (SX) spectrometer is installed at the ADITYA-U tokamak, operating within the range of 1–30 keV generating a 4 K channel spectrum. The energy calibration, spectra transformation from channel space to the energy space, is a pre-requisite for any spectroscopic measurement. The calibration is performed by natural radioactive sources ²⁴¹Am, ¹⁰⁹Cd, ¹³³Ba, and ⁵⁵Fe having micro-curie strength. Two-point and multipoint calibrations are applied to the SDD spectra. The results from the two processes establish that the multipoint calibration works well for the identification of the photon energy due to the realization of the detector linearity for a wider band.

A model to assess the design criteria for a convergent-divergent magnetic nozzle is provided. This model is based on an ideal single-fluid magnetohydrodynamic flow assumption to evaluate the acceleration and detachment in the magnetic nozzle. A thermodynamic correlation of plasma internal energy during the propagation in a magnetic nozzle is presented. The result reveals the limitation of a magnetic nozzle on the conversion of internal energy to kinetic energy, where an upper limit of around 19% is derived, assuming plasma undergoes ideal conditions. In addition, criteria derived from the model also point out that a threshold on magnetic flux density exists to prevent the occurrence of flow discontinuity during propagation along the magnetic nozzle. The result hints at the essential role of the electric field on the acceleration processes of a magnetic nozzle, which can potentially be the key to overcoming the limitation of a magnetic nozzle's performance.

Inspired by the root systems of Lie algebras of rank 2, we propose a mathematical method to engineer new 2D materials with double periodic structures tessellating the plane. Concretely, we investigate two geometries relaying on squares and hexagons exhibiting the D₄ × D₄ and D₆ × D₆ dihedral group invariances, respectively. Due to lack of empirical verifications of such double configurations, we provide a numerical investigation by help of the open source quantum espresso. Motivated by hybrid structures of the graphene, the silicene, and the germanene, we investigate two models involving the D₄ × D₄ and D₆ × D₆ dihedral symmetries which we refer to as Si4Ge4 and Si6C6 compounds, respectively. For simplicities, we study only the opto-electronic physical properties by applying an electromagnetic source propagating in linear and isotropic mediums. Among others, we find that such 2D materials exhibit metallic behaviors with certain optical features. Precisely, we compute and discuss the relavant optical quantities including the dielectric function, the absorption spectra, the refractive index, and the reflectivity. We believe that the Lie algebra inspiration of such 2D material studies, via density functional theory techniques, could open new roads to think about higher dimensional cases.

Supercapacitors (SCs), among other electrochemical device applications, require materials with maximal energy storage capacity, and the stacked two-dimensional titanium carbide MXene (Ti3C₂) sparked the development of these materials. This paper embellished to present smoothed MXene/PbCrO₄ nanocomposite via co-precipitation method along with modified sol–gel achieved lead chromate (PbCrO₄) nano-crystalline for energy storage and photocatalytic applications using ethylene glycol as connecting agent to restrict nano-particle growth. It is evident from photoluminescence spectra that peak intensity has decreased, whilst Raman spectra show the presence of MXene and lead peaks in the nanocomposite, whereas FTIR has revealed the presence of functional groups in synthesized material. According to calculations made using EIS spectra, the charge transfer resistance is 1.4 Ω, with the electron shift rate constant K_app value 6.98 10⁻⁹ cm s⁻¹. Additionally, the electrochemical performance of the designed material in supercapacitors at 0.3Ag⁻¹ of current density indicates elevated capacitance of 5408 Fg⁻¹ with scan rate of 10 mV s⁻¹ using 1MKOH aqueous electrolyte, resulting in power and energy densities of 2991.8 W kg⁻¹ and 110.1 Wh K⁻¹ g⁻¹, respectively. UV–vis spectra shows the nanocomposite has a 1.86 eV band gap that, in the presence of direct sunlight, might cause the destruction of MB dye at a rate of 92.79%. These findings suggested that the newly created MXene/PbCrO₄ nanocomposite demonstrates evidence of substantial features as compared to single materials has potential as an electrode material for supercapacitors as well as best photocatalyst for the degradation of organic pollutants regarding water purification.

Two compounds were prepared: cadmium oxide/cobalt oxide (referred to as oxide A) and silver decorated cadmium oxide/cobalt oxide (referred to as oxide B). Yttrium aluminium garnet (Nd:YAG) lasers, doped with neodymium, were used to irradiate the samples at 532 nm and 1064 nm. The effect of the Nd:YAG laser on the morphological, optical, structural, and antibacterial properties was investigated. The XRD data shows that both oxides are polycrystalline, and the laser irradiation increases the crystal size. Additionally, scanning electron microscopy results (SEM) show that particle size increases with laser irradiation and laser wavelength. While both oxides expand under the influence of a laser, oxide A has a larger optical band gap than oxide B. The intensity of PL increases with the pulsed laser effect and the addition of Ag. The antibacterial test shows that silver is quite effective in eliminating germs and other harmful microbes for human health. Moreover, the results show that, after adjusting the other laser parameters, the wavelength of 1064 nm performed better compared to the wavelength of 532 nm in pure water.

A series of thiophene bridged donor molecules (Pph-M1 to Pph-M5) have been developed by adapting the end capped alteration strategy. Five different acceptor groups have been substituted using thiophene as a bridging group. The designed geometries have been optimized and various analysis have been performed using CAM-B3LYP 631-G (d, p) method. Optical and photovoltaic characteristics of all the developed molecules have been investigated by performing Frontier molecular orbital analysis that determines the charge transfer that occurs within the newly planned systems. Moreover, density of state (DOS) analysis was also computed. These analysis suggests the contribution of individual fragments of the devised chromophores in formation of HOMO and LUMO. The developed molecules have exhibited reduced band gap values from 3.28–4.02 eV while the reference molecule being with the higher band gap of 5.87 eV. Further, absorption analysis were performed and the spectra for all the investigated molecules have been obtained showing an increased λ_max values than the reference molecule (Pph-M). Dipole moment (μ), light harvesting energy (LHE), reorganization energy (RE) and open circuit voltage (V_oc) of the studied molecules are also evaluated and the outcomes suggest that our designed molecules withhold outstanding electronic and opto-electronic properties and can be used as propitious donor material for application in future efficient organic solar cell.

We theoretically investigate the topological-edge-state spin transport in asymmetric three-terminal silicene-like nanodevice. Since silicene-like materials are honeycomb structures with considerable spin-orbit interaction (SOI), they possess both Dirac electron and topology insulator behaviors. In the three-terminal silicene-like nanodevice, the SOI realizes helical edge state and brings fully spin polarization selectively without external field. Firstly, we find that the spin degeneracy breaking gives rise to spin-polarized transport, i.e., up-spin electron and down-spin electron propagating to different leads from the top lead. The distribution of edge-state spin-dependent current in the real space indicates that an up-/down-spin channel to the left/right lead is opened at the interface of the present nanodevice. Secondly, the spin-polarized transport behavior has a competition with the effect of asymmetric transport, which prefers propagating the up- and down-electrons from top lead to the same (right) lead. Interestingly, as the geometric size variation is considered, the results show that the width increase of the horizontal armchair (top vertical zigzag) lead reinforces the spin-polarized (asymmetric) transport. However, when both the armchair and zigzag leads increase simultaneously, the spin-polarized transport becomes the dominant effect. Therefore, this edge-state spin-polarized transport behavior is topologically protected and very robust as the whole geometric size of the nanodevice increases. These properties of the topological-edge-state spin transport enable the asymmetric three-terminal silicene-like nanodevice a spin filter or a spin valve, and might contribute to the silicene-like nanocircuit engineering and spintronics application.

In this current project, silicon substituted zirconia matrixes with the general formula of Si_xZr_(1-x)O₂ at x = 0.1–0.6, step size 0.1 have been fabricated through powder metallurgy route. All the samples have been sintered at 1200 °C for four hours in an air furnace. The structural, refinement, 3-dimensional view, functional groups, optical and electrochemical properties have been investigated using x-ray diffractometer (XRD), Rietveld refinement, diamond and Vista software, Fourier Infrared spectroscopy (FTIR), Diffuse reflectance spectroscopy (DRS), and Cyclic voltametric (CV) respectively. The XRD and Rietveld refinement exhibit sharp peaks which are matched with JCPD card no 07-0343, the single monoclinic phase is achieved in all samples. The goodness of fit clarifies the proper growth of the crystal. Furthermore, the theoretical evaluation is cross-matched with refinement data. The ATR-FTIR analysis indicates the characteristic bands of monoclinic zirconia. Due to the creation of active sites on the electrode surface, the average surface area of these oxides as determined by SEM is in the range of 58–63 m² g⁻¹. The lowest band gap and higher ionic conductivity values reveal the higher compatibility rate of charge carriers. The maximum specific capacitance (C_sp) obtained from CV, GCD, and EIS analyses using walnut shell a.c is 903.1 A g⁻¹, which are excellent materials for pseudocapacitive electrodes.

The auto combustion technique was employed to synthesis magnesium nano ferrite (MgMo_xFe_2-xO₄). The impact of Mo-doped on the crystal's structural, morphological, and elastic properties were inspected by applying x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy techniques. Pursuant to the XRD analysis, all samples have a cubic structure with single-phase. The average crystallite size was identified to be in the nanometer range confirmed by SEM and TEM investigations. FTIR data was implemented to assign the force constants of the octahedral and tetrahedral sites. Elastic moduli including the Poisson ratio, Young's modulus, bulk modulus, and rigidity modulus have been estimated. The division of elastic moduli for all synthesized concentrations was interpreted using binding forces between ions of the cubic lattice spinel. Over and above, the AC conductivity (σ_AC) and dielectric properties and their frequency dependence were investigated for the nano ferrites samples as a function of dopant Mo content and temperature. Finally, the radiation shielding capacities of the proposed samples against gamma and fast neutron radiation have been assessed. The findings reveal that the higher the Mo content, the lower the value of the mass attenuation coefficient. There is no significant diversity between the obtained mass attenuation coefficients for the nano and the micro. Among the samples investigated in this study, the highest Mo concentration sample had the largest fast neutron removal cross-section.

We report an analysis of the structural, electronic, mechanical, and thermoelectric properties of oxide double perovskite structures, specifically the compounds Ba₂MgReO₆ and Ba₂YMoO₆. Our study employs first-principles density functional theory (DFT) as the investigative methodology. The electronic attributes of the examined compounds are explained by investigating their energy bands, as well as the total and partial density of states. The computational evaluation of the electronic band structure reveals that both compounds exhibit an indirect band gap semiconductor behavior in the spin-down channel, while demonstrating metallic properties in the spin-up channel. The magnetic attributes indicate a ferromagnetic nature, thus categorizing some double perovskite compounds as materials displaying half-metallic ferromagnetism (HM-FM) in addition to some other properties such as metallic and semiconductor in paramagnetic or antiferromagnetic states. The outcomes derived from the analysis of elastic constants confirm the mechanical robustness of the studied double perovskite compounds. Notably, the computed data for bulk modulus (B), shear modulus (G), and Young's modulus (E) for Ba₂MgReO₆ surpass those of Ba₂YMoO₆. The calculated ratio of Bulk to shear modulus (B/G) indicates that both compounds possess ductile characteristics, rendering them suitable for device fabrication. Furthermore, both compounds display outstanding electronic and elastic properties, positioning them as promising contenders for integration within mechanical and spintronic devices. Finally, we investigate into the thermoelectric potential by evaluating parameters such as the Seebeck coefficient, electrical conductivity, thermal conductivity, figure of merit, and power factor. This assessment is conducted using the semiclassical Boltzmann theory and the constant relaxation time approximation, implemented through the BoltzTraP code. The results indicate that the investigated double perovskite oxides hold promise for utilization in thermoelectric applications.

This paper investigates the influence of CNTs (carbon nanotubes) surface density on the electromechanical actuation of dielectric elastomer (DE) actuators. A filter transfer technique is utilized to deposit CNTs electrodes on VHB (Very-High-Bond) 4905 elastomers with different surface densities. The electromechanical characteristics of VHB 4905 elastomers with different surface densities of CNTs electrodes are evaluated experimentally. Theoretical models are simultaneously established to analyze with experimental measurements. It is found that increasing the CNTs surface density may alter the dielectric constant and modulus of DE actuators which results in a non-monotonic varying behavior of the electromechanical deformation under DC voltages. Furthermore, the stability and repeatability of the CNTs electrodes under AC voltage are verified by conducting additional experiments under different frequencies. This research can be used to determine the CNTs surface density to optimize the electromechanical actuation of DE actuators.

Drawing upon the physical phenomenon of polarization transformation, this paper proposes an ultra-broadband, high-efficiency linear polarization converter composed of a metallic grating, an L-shaped metallic patch, and a dielectric substrate. The polarization conversion properties have been scrutinized using the finite element numerical simulation software CST. The computational outcomes reveal that the polarization converter operates within the frequency range of 0.5 THz to 1.8 THz, exhibiting a relative bandwidth of 113%, a transmission coefficient exceeding 0.87, a polarization conversion efficiency approaching 100%, and a phase coverage spanning 360°. Furthermore, a Fabry–Perot interference model was established utilizing Matlab to corroborate the concurrence between the theoretical analysis and the numerical findings. The polarization converter metasurface amalgamates both phase and transmission amplitude variations to accomplish not only a two-dimensional focusing lens operating between 1.55 THz and 1.65 THz, but also a spatial imaging capability utilizing transmission amplitude variation within the 0.5 THz to 1.15 THz range. The outcomes demonstrate that the devised metasurface exhibits ultra-broadband and high transmission efficacy, thus providing novel insights for the versatility of terahertz wave polarization and phase manipulation.

In few recent years, great and significant efforts are devoted from researcher all over the world to pursue the revolution of photovoltaic's materials and their uses in various applications. In the present work, a series of ab-initio simulations based on the density functional theory DFT plane wave pseudo-potential (PW-PP) method and hence performed towards the perselenoborate materials ABSe₃ (A = Rb,Cs) for the first time along the three main polarizations of the incident wave directions [100], [010] and [001] with the aim of exploring their structural, electronic, optical and elastic properties. The generalized gradient approximation Perdew–Burke–Ernzerhof (GGA-PBE) carried out with CASTEP code is used for the exchange–correlation potential. The computed results showed that the structural properties of investigated compounds are very good agreement to the available experimental data, showing that the current calculations are quite accurate. Moreover, the density of states and electronic band structure calculations reveal that RbBSe₃ (CsBSe₃) compounds exhibit direct band gap semiconductor nature 1.66 eV (1,82 eV) respectively within the optimal range band gap 1eV–2eV required for photovoltaic's applications makes them having great potential to obtain efficient Perovskite solar cell PSC. Additionally, our finding optical properties calculations reveal that the two investigated compounds exhibit strong absorption (prominent absorption peaks up 2,4 × 10⁵cm⁻¹) in UV range, while the real part of the refractive index for RbBSe₃ (CsBSe₃) was 2.62 (2.60) respectively which might be beneficial for photovoltaic application (top cell in solar cell) and optical applications. Also, high optical conductivity (∼10¹⁵sec⁻¹) is found to be observed in visible ultraviolet range (1.7 eV to 30 eV). The lower reflectivity seen by R_bBSe₃ compared to C_sBSe₃ in the larger energy spectrum of electromagnetic radiation suggests that R_bBSe₃ compound is more suitable for electronic applications. Further, once the elastic constants are obtained, the calculated mechanical properties, bulk modulus (B), shear modulus (G), the ratio B/G, Young's modulus (E), Poisson's ratio (ν), anisotropy universal (A^U) are calculated. Our calculated Young's modulus indicate that the CsBSe₃ is less hardness compared to RbBSe₃, while Poisson's ratio calculated leads them to have a character ionic and RbBSe₃ is more ductile than CsBSe₃. The calculation value of θ_D predicted from elastic constants appears low which is closely related to many physical properties such as specific heat and melting temperature. Finally, the finding results reveal another way of investigating mechanical stability, where both compounds are mechanically stable since all elastic constant computed are perfectly satisfied the Born stability criteria, flexible and brittle. Finally, we hope that all these results will be helpful for designing photovoltaic and optoelectronic devices.

Scholars are shifting their attention to the development of environmentally friendly materials with a high degradability of environmental pollutants. Among various photocatalytic materials, zinc oxide (ZnO)/reduced graphene oxide (rGO) nanomaterials can meet these requirements. In this study, ZnO/rGO nanomaterials with different hydrothermal temperatures were fabricated through a hydrothermal method. We determined the hydrothermal temperature variations to create different structures and identify the morphologies and sizes of the ZnO/rGO material. The average crystal size of ZnO/rGO nanomaterials decreased from 32.25 nm to 30.30 nm when the hydrothermal temperature was increased from 100 °C to 180 °C. The detailed x-ray diffraction (XRD) study showed that the diffraction peak position of ZnO decreased, the lattice constant increased, and the unit cell volume increased with the increase in hydrothermal temperature. rGO-related diffraction peaks were also observed in the XRD patterns of ZnO/rGO samples, which indicates the formation of a ZnO/rGO crystalline structure. Fourier transform infrared spectra revealed the chemical bonding of ZnO and rGO materials. The photoluminescence (PL) spectra of ZnO/rGO nanocomposites presented two characteristic emission peaks at 383 and 558 nm. The Raman scattering spectra of ZnO/rGO nanomaterials exhibited ZnO-related peaks at 329, 436, and 1123 cm⁻¹ and rGO-related peaks at 1352, 1579, 2706, and 2936 cm⁻¹. The ultraviolet-visible (Vis) absorption spectra of ZnO/rGO nanomaterials manifested the characteristic absorption peaks of ZnO and rGO at 381 and 291 nm, respectively. The photocatalytic properties of ZnO/rGO nanomaterials were studied through the decomposition of methylene blue (MB) under Vis light. The effect of hydrothermal temperature on the properties of ZnO/rGO materials and the photodecomposition mechanism of MB were investigated in detail.

Photodiodes have gained great attention for lightning control and optical communication over the last two decades. To obtain faster and more sensitive photodiodes are important for industrial applications. In this study, atomic layer deposition (ALD) technique was used to fabricate ZnO interlayer on p-Si, and thermal evaporation technique was employed to deposit Ag rectifying and Al ohmic contacts on ZnO and back surface of p-Si, respectively. The UV–Vis spectrometer was used to characterize optical behaviors of the ZnO interlayer. I-V measurements were conducted to characterize of Ag/ZnO/p-Si heterostructure for various solar light power intensities of dark, 20, 40, 60, 80 and 100 mW cm⁻² and at various wavelengths from 351 nm to 800 nm by 50 nm intervals. According to I-V characteristics, the device exhibited increasing current at reverse biases depending on increasing light power intensity, and this confirmed photodiode behavior. Various diode parameters such as rectifying ratio, threshold voltage, series resistance, barrier height, etc. were determined and discussed in details from forward bias characteristics to investigate diode characteristics of the Ag/ZnO/p-Si heterostructure. The photodetection parameters such as responsivity, specific detectivity and external quantum efficiency (EQE) also were investigated. The Ag/ZnO/p-Si heterostructure exhibits good photodetection performance at all visible range of electromagnetic spectrum and can be good candidate for optoelectronic applications.

Stacking engineering have played the very important role in tuning the structural, electronic and thermoelectric properties of 1 T ZrS₂ bilayer. All these calculations are performed by using first principles calculations in conjunction with the Boltzmann transport theory. The structural properties of bilayer with all possible stackings i.e., AA1, AA2, AA3, AB1, AB2 and AB3 along with their respective interlayer distance (d) are calculated. Electronic properties of these stacking bilayers have showed the indirect band gap in all the stacking pattern. The dynamical stability of AA1, AA2 and AA3 stackings are more in comparison to other stacking bilayers. The lattice thermal conductivity with values 0.57 W mK⁻¹, 0.47 W mK⁻¹ and 1.45 W/mK for stackings AA1, AA2 and AA3, are obtained, respectively. The obtained values of ZT are 0.86, 0.83 and 0.82 for AA1, AA2 and AA3 stackings, respectively, at room temperature, for n-type doping. The present study has provided the effective approach for selecting the good stacking pattern of 1 T ZrS₂ bilayer for various applications with excellent thermoelectric performance.

We present a comprehensive spectral analysis of cylindrical quantum heterostructures by considering effective electronic carriers with position-dependent mass for five different kinetic-operator orderings. We obtain the bound energy eigenstates of particles in a three-dimensional cylindrical nanowire under a confining hyperbolic potential with both open and closed boundary conditions in the radial and the axial directions. In the present model we consider carriers with continuous mass distributions within the dot with abrupt mass discontinuities at the barriers, moving in a quantum dot that connects different substances. Continuity of mass and potential at the interfaces with the external layers result as a particular case. Our approach is mostly analytical and allows a precise comparison among von Roos ordering classes.

Wear leads to the roughening of bearing surfaces, increased internal clearances, decreased rotational precision, and amplified vibration and noise, ultimately causing the bearing to fail to meet specified performance criteria. This study employs the quasi-static analysis method to examine bearing sliding behavior. Based on the Archard wear model and Hertz contact theory, a computational model for wear depth in lubricated conditions is established for rolling ball bearings, accounting for both the rolling and sliding of the rolling elements. The distribution law of load and wear coefficient along the raceway circumference are analyzed, along with the characteristics of stress and sliding velocity in the contact region. The study investigates the impact of rotational speed, load, surface roughness, and raceway curvature coefficient on the wear coefficient, wear depth, and minimum oil film thickness. Furthermore, sensitivity analysis is conducted on the parameters of the wear depth model. Finite element analysis, utilizing ANSYS Workbench, is employed to study the evolution of surface wear on the raceway of deep groove ball bearings and explore the dynamic relationship between contact stress and wear depth. These findings offer important theoretical guidance for the design, selection, and maintenance of rolling bearings.

Photovoltaic studies in DSSC have continued to be fascinated by chalcone derivatives because of their straightforward synthesis, green synthetic process and low toxicity properties using Claisen-Schmidt condensation method. In this report, the implementation of the newly synthesized pyrenyl chalcone derivatives, Py1 and Py2 as dye-sensitizers and the characterization studies are further discussed. The grown crystals are characterized via several spectroscopic analyses such as ATR, ¹H and ¹³C NMR and UV–vis analyses. The UV–vis analysis shows a lower energy gap in Py1 (2.79 eV) in comparison to Py2 (2.90 eV) which further indicates better flow of charge transfer. The analysis of crystal packing reveals the arrangement of head-to-head by intermolecular π—π contacts and head-to-tail via intermolecular C–H···O interactions in Py1 and Py2, respectively. The intermolecular interactions act to stabilize the crystal structure and further improve the charge transfer within the dyes and enhancement of DSSC efficiency. In electrochemical analysis using cyclic voltammetry (CV), Py1 and Py2 are found in the suitable HOMO and LUMO energy levels which confirms their applicability as photosensitizer materials. After the fabrication process, DSSC layers are continued for FESEM and EDX analyses before proceeding for the performance study. The Py1 with D-π-A architecture has significantly revealed a higher efficiency than D-π-D structure of Py2.

Quaternary (Tl₂₀Se₇₀Ge₁₀)_0.85Sb_0.15 chalcogenide glass was synthesized using melt-quenching and thermal evaporation techniques for bulk and thin film samples, and its amorphous character was confirmed by XRD. Based on different models of non-isothermal crystallization kinetics, the average values of the glass transition ${\mathop{E}\limits^{\unicode{x00305}}}_{g}$ and the crystallization ${\mathop{E}\limits^{\unicode{x00305}}}_{c}$ activation energies are 121.33 and 82.94 kJ mol⁻¹, respectively. The crystallization mechanism in the examined composition is 2D nucleation growth, according to Avrami exponent $n.$ Thermal parameters of the studied quaternary glass, like fragility ${F}_{g},$ fluctuation free volume ${F}_{{FV}},$ reduced glass transition temperature ${T}_{{rg}},$ thermal stability ${SP}$ and glass formation ability ${GFA}$ were investigated and indicated that the (Tl₂₀Se₇₀Ge₁₀)_0.85Sb_0.15 ChG exhibits a good ability of glass formation and thermal stability. The obtained results of the dc electrical conductivity ${\sigma }_{{dc}}$ are found to increase with temperature and decrease with film thickness. The electrical conduction activation energy ${\unicode{x02206}E}_{\sigma }$ (0.583 ± 0.004 eV) is thickness independent and the predominant conduction mechanism is the hopping of charge carriers in the band tail localized states. The ($I\mbox{--}V$) curves of (Tl₂₀Se₇₀Ge₁₀)_0.85Sb_0.15 chalcogenide glass film samples were analyzed and shown to be appropriate for a memory switch. The mean value of the threshold voltage ${\mathop{V}\limits^{\unicode{x00305}}}_{{th}}$ decreases exponentially as temperature increases, whereas it increases linearly as film thickness increases. The values of threshold voltage ${\varepsilon }_{{th}}$ and threshold resistance $\unicode{x02206}{E}_{R}$ activation energies are 0.282 ± 0.003 and 0.521 ± 0.004 eV, respectively. The obtained switching characteristics data were discussed in view of the electrothermal model motivated by current channel Joule heating. These findings highlight the suitability of the investigated composition for various optoelectronic applications, such as memory switching devices, optical data storage, phase-change memories and optical fibres sensing devices.

Perovskite-based tandem solar cells emerged as potential candidates for efficient photovoltaic applications. These devices exhibit high optical absorption properties and tunable direct band-gap. In this work, a novel lead-free Perovskite-SnS Tandem solar cell based on alternative charge transport layers combined with plasmonic-based light management approach is proposed. Accurate numerical investigation is carried out to assess the influence of the charge transport layers of top sub-cell on the optoelectronic properties of the tandem cell. The obtained results reveal the potential of SnO₂ and CuO materials as electron and hole transport layers, respectively, demonstrating a good conduction band offset (CBO) and thereby enhanced recombination losses. Furthermore, the role of Gold-nanoparticles in enhancing absorption and light-trapping mechanisms in the bottom SnS-based sub-cell is investigated using FDTD computations. It is found that the optimized tandem cell with Au-NPs exhibits a high power conversion efficiency of 20.1%. Therefore, this work can open up new paths to boost the power conversion of Sn-based Perovskite/SnS Tandem cells for high-performance and eco-friendly photovoltaic applications.

This study addressed the nano-mechanism of CO₂ capture by Al-doped, B-doped and N-doped single-walled silicon carbide nanotubes (SWSiCNTs) using the prominent density functional theory. The results showed absolute interactions between CO₂ and B- and N- impurity atoms of the SWSiCNT surface with the highest adsorption energy of −1.85 eV and −1.83 eV respectively. Analysis of the binding energy of CO₂ to Al-doped SWSiCNT revealed that chemisorption between them is stronger than B-doped and N-doped SWSiCNTs. Results from optical adsorption spectra revealed that both B-and N-doped systems adsorb CO₂ in the visible region of the electromagnetic spectrum while B-doped SiCNT shows the highest adsorption. This study recommends B- and N-doped SiCNTs as candidates for CO₂ capture and storage with higher efficiency by B-doped SiCNT, while the performance of the Al-doped system was underscored.

Two-dimensional structures have attracted attention for application in nanoelectronics and optical devices; then, in this work, we are reporting the predicted physical properties (from first-principles calculations) for the two-dimensional PbC systems. Those physical properties reveal that the PbC monolayers (M-PbCs) in crystallographic planes (111) and (100); moreover, the PbC₂ structures (paramagnetic and anisotropic compounds) are thermodynamical, structural, and mechanically stable but energetically and dynamically unstable at T = 0 K. However, the PbC₂ non-magnetic (NM) is the most stable system at high temperatures. The M-PbCs exhibit sp² hybridization while the PbC₂ NM shows sp³d² hybridization, forming a hexagonal lattice; meanwhile, the strong interaction at the C's double bond in the PbC₂ ferro and antiferromagnetic configurations (MAG) generates a rectangular lattice. These systems are ductile materials; however, the PbC₂ (with metallic bonds) is more ductile than the M-PbCs due to the pronounced participation of the Pb 6p-orbitals. The M-PbCs have associated greater values for the hardness (than those for the PbC₂ systems), but at high temperatures, the PbC₂ MAG exhibits the highest mechanical resistance. The calculated optical data show that the M-PbCs and the PbC₂ NM are promising as refractory materials. At the same time, the PbC₂ MAG could be helpful in optical and optoelectronic devices capable of operating in the low frequencies of the UV region and in the infrared and visible regions.

This work analyses the comparative effects of period-four transition metal (TM) dopants for CO molecular adsorption on the monolayer Graphene (Gr) supercell using the density functional theory (DFT) based ab initio method for the first time. Ten different TM dopant species (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cr, Zn) have been incorporated and extensively studied in the context of Carbon Monoxide (CO) adsorption. The study elaborates on the effects of metallic doping in Gr on structural stability, electronic properties, adsorption strength, transduction efficacy, and CO recovery time. The study reveals that introducing each period-four TM dopant in the Gr lattice changes the semi-metallic nature, wherein distinct modulations in the energy band structure and the total density of state profiles can be observed after CO adsorption in each doped Gr matrix. The C atom of the polar CO molecule preferentially adsorbed on the doped TM, forming physical C-X (X: metal) bonds and resulting in slight vertical displacement of the dopant towards adsorbed CO. The results exhibit that depending on the strength of CO adsorption, the metallic dopants can be placed in the following order: Ti > V > Cr > Mn > Fe > Co > Ni > Cu > Zn > Sc, with a significant improvement in charge transfer during CO adsorption after Sc, Co, Ni, V, and Zn doping in Gr. Specifically, the Ni, Zn, and Sc-doped Gr ensures an efficient trade-off between adsorption stability and recovery time with high selectivity in CO₂ and N₂ environments.

The characteristics of metal–organic framework (MOF) composites make them the most significant materials for energy conversion applications. MOFs are hybrid molecular frameworks synthesized using metal ions like Copper, Cobalt, Zinc, Nickel, etc and organic ligands such as BTC, NDC, etc. To meet and fulfill futuristic energy demands and needs, it is feasible to expand cost-effective energy conversion solar cell devices using MOF materials, therefore in the present work, the Cobalt-based MOFs (Co-MOF) are synthesized by coordinating Cobalt nitrate and 1,3,5 Benzene tricarboxylic acid (BTC or Trimesic acid) ligand using the Solvothermal method. To study the physiochemical properties of synthesized Co-BTC MOFs, these have gone through a variety of characterization processes where the structural exploration unveils that the intensity of the dominant peak obtained at 18.7° gradually decreases with a decrease in the concentration of trimesic acid ligand. First and second weight losses, corresponding to release of the solvent molecules and breakdown of the frameworks, respectively, were detected by thermogravimetric analysis (TGA) measurements. In the FTIR spectra, metal-oxide, modified benzene, carboxylic, and hydroxyl groups with different modes of vibrations are observed. Analysis of surface morphology demonstrated creation of rod-like geometry to the synthesized materials, whereas elemental studies inveterate effective formation of the Co-BTC MOFs. Additionally, the optimized Co-BTC MOF is applied as a potential interfacial layer in solar cells and the outcome implies that the device designed with 10 Co-BTC LBL cycle evolutions provided relatively desirable solar cell performance parameters. The present findings recommended that material progression is necessary to develop cost-effective and high-performance MOF-based solar cell devices.

A new self-similar graphene structure with different construction parameters is created to investigate the scalability of transmission coefficient. The transfer matrix formalism is used to calculate transmission spectra for generations of the self-similar structure. Two cases are analyzed: In the first case, the barriers were created by substrates, which induce a gap in the graphene. In the second case, the barriers were created by electric fields that can produce a displacement of the Dirac cones. We find that both cases show self-similarity patterns in their transmission spectra, which can be demonstrated through analytical equations called scaling rules, those rules connecting the generations of the structure. It results when the height of the barriers (V₀) is scaled or not, it gives different scaling rules, which shows that V₀ can be a revealing factor to find alternatives to scaling the transmission coefficient. Scaling rules can be useful because one can determine the transmission coefficient of generation i + 1 only by knowing a generation i.

Apatite-type compounds have attracted attention due to their flexible crystalline structure besides high chemical stability, which increases the interest in understanding and modifying their properties to achieve the requirements for applications in catalysis and energy devices. In order to attend these demands, this paper investigates the optical properties of apatite-type Sr₂RE₈(SiO₄)₆O₂ ceramics (RE = rare earth) by using diffuse reflectance and photoluminescence spectroscopies. Intraconfigurational f-f transitions, charge transfer bands, and energy gaps were identified and detailed discussed in terms of their relationships with the structural features of the rare earth apatites. Although all materials have the same hexagonal space group (P6₃/m, # 176), the band gaps varied between 3.51 and 3.95 eV, for Eu- and Yb-containing apatites, respectively, showing the influence of their ionic radii and their electronic configurations on this property. In this sense, diffuse reflectance spectroscopy emerges as a powerful tool to study the optical properties of rare earth-containing materials as a complementary technique to photoluminescence spectroscopy. In this work, these techniques were discussed in association, which allowed us to provide a complete set of optical information that improves the understanding of apatite-type materials, as required in advanced technological demands.

The (1-x)Ba(Zn_1/3Nb_2/3)O₃ − xBaWO₄ (0 ≤ x ≤ 0.25) ceramics were manufactured by the conventional solid-phase reaction process, and the effects of BaWO₄ addition on the phase composition, crystal structures, microstructure, and microwave dielectric properties were investigated. X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy were implemented to explore the phase composition, crystal structure and chemical states of the samples, respectively. According to XRD analysis, the main phase of the samples was assigned as Ba(Zn_1/3Nb_2/3)O₃ (BZN), while the secondary phases contained Ba₅Nb₄O₁₅ and BaWO₄. Scanning electron microscopy photographs suggested the average grain size firstly increased and then decreased with the replacement of W⁶⁺ ions to Nb⁵⁺ ions in BZN. Due to the proper substitution amount of W⁶⁺, the apparent density increased accordingly. The microwave dielectric properties were closely associated with the secondary phases and apparent density. Finally, (1-x)Ba(Zn_1/3Nb_2/3)O₃ − xBaWO₄ (x = 0.15) ceramics sintered at 1325 °C for 4 h had excellent microwave dielectric properties with ε_r = 33.11, Q × f = 90,479 GHz, and τ_f = +0.86 ppm °C⁻¹.

This study presents results from quantum chemical simulations of the synergetic interaction, electronic structure, and optical properties of calcium-silicate hydrates (C-S-H) reinforced by graphene-nanoribbons and single-walled carbon nanotubes (SWCNT). The calculations show that C-S-H/graphene-nanoribbon and C-S-H/SWCNT composites are stabilized by electrostatic interaction due to the charge transfer from Ca ions at the interface of C-S-H to the nearby C atoms of the graphene-nanoribbon and SWCNT. Removing Ca ions at the interface drastically decreases the strength of interaction into a weak van der Waals type. The Bader charge transfer analysis and electron distribution topology further confirm these results. Generally, the electronic states of the graphene-nanoribbon and SWCNT are shifted to lower energy in the complex. The electronic structure of graphene-nanoribbon and SWCNT is susceptible to the Ca ions-rich C-S-H environment. The composites' overall absorption spectra can be considered superimposed of the isolated nanocarbon and C-S-H except in the lower energy region due to charge transfer and realignment of energy states. The results presented here reveal the bonding mechanism of the C-S-H with nanocarbon at the fundamental level. This work serves as a reference for the nanoengineering cement-based material with nanocarbon for the next-generation smart infrastructure.

This study performed first-principles calculations based on density functional theory to study the interlayer electronic and optical properties of NbSe₂/MoS₂ heterostructures. Bandgap in 2H-MoS₂ is often quite large typically around 1.8 eV, showing slow response time and low photoresponsivity (R); however, a slight bandgap variation can improve the properties of semiconducting and conducting heterostructures. Different stacking configurations of the interlayer van der Waals interaction were precisely investigated. Due to their unique properties, atomically thin NbSe₂/MoS₂ based heterostructures hold great potential for future electronic and optoelectronic devices. LDA, GGA, GGA with SOC, and HSE06 are used to study the monolayers of MoS₂, NbSe_2, and their T and H stacking structures. Our results demonstrate that the metallic NbSe₂ effect on the semi-metallic MoS₂ reduces the band gap of MoS₂ up to 140 meV. Moreover, these heterostructures exhibit outstanding absorption properties from visible to ultraviolet regions, which makes them ideal candidates for optoelectronic applications, particularly in photodetectors.

The state-of-the art density functional theory (DFT) is used to clearly resolve the two parallel cyclopentadienyl rings of ferrocene, which are either staggered (D_5d symmetry) or eclipsed (D_5h symmetry), in their ground-state conformation. Present result revealed that the eclipsed conformer with D_5h point group represents the true minimum ground state structure of ferrocene. Natural population analysis is used to determine how atomic charge is distributed across different atoms of ferrocene D5h conformer and also the distribution of electrons in the core, valence, and Rydberg sub-shells. It is further investigated in potential energy scan that the rotation of the dihedral angle δ from 0° to 3π/5 will reproduce three times D_5h or D_5d conformers periodically as the period of 2π/5 due to the pentagonal structure of the CP ring. Further to examine optical spectra in the ultraviolet-visible (UV–vis) range, configuration interaction single (CIS) and time-dependent density functional theory (TDDFT) have conducted which help in locating the significant electronic shifts between different energy levels. Absorption spectra for high spin states were also generated in order to comprehend the characteristics of low-lying spin excitation. According to our estimates, the greatest absorption intensity is restricted to an energy range of 4–6 eV. Knowledge of ferrocene conformers will improve the research on other metallocenes and their derivatives, which have applications in biotechnology, nanotechnology, and solar technology.

Potassium-ion batteries (KIBs), with their abundance of resources, lower cost, high ion conductivity, and comparable redox potential, hold potential as an alternative to lithium-ion batteries (LIBs) for large-scale energy storage. Nonetheless, the scarcity of high-performance electrode materials remains a major obstacle in the advancement of KIBs. Here, the viability of bismuthene as an anode material for KIBs was systematically investigated using first-principles calculations. We found that bismuthene exhibits a maximum adsorption capacity of two layers of K atoms, offering a moderate theoretical capacity of 256.5 mAh g⁻¹. Additionally, the adsorption of K atoms on bismuthene leads to a notable enhancement in the electronic conductivity. Moreover, the ultralow average open circuit voltage (0.17 V) and diffusion barrier (0.02 eV) of K on bismuthene monolayer along the zigzag direction, suggesting a high energy density and outstanding rate performance of batteries. Hence, bismuthene demonstrates remarkable potential as a high-performance KIBs anode material, making it a hopeful contender in the field of energy storage.

We studied ex situ thermal cycle annealing on metalorganic vapor phase epitaxy (MOVPE) grown CdTe on (211) Si substrates for dislocation density reduction and its effect on the performance of gamma-ray detector fabricated. The ex situ annealing was performed by varying temperatures from 600 °C to 1000 °C for different anneal durations and cycles varied from 1 to 7 in a hydrogen environment. Gamma-ray detector was fabricated in a p-CdTe/n-CdTe/n⁺-Si heterojunction diode structure. Dislocation densities were evaluated by the etch pit density (EPD) technique. Dislocation densities were decreased when the annealing temperature was increased above 800 °C. This is due to the annealing enhancing dislocations' glide motion, which annihilate and reduce their density. The device property could be improved by subjecting the annealing during the early stage of the growth. Devices subjected to annealing showed lower dark current and improved gamma detection property when compared to the devices that were not subjected to annealing during their fabrications.

Ti₂C as a new two-dimensional layered MXene material has a certain potential in the sensor field. The adsorption properties of gases (NH₃, NO, ethanol, CO) on intrinsic Ti₂CO₂ and transition metal atoms (Fe, Zn) doped Ti₂CO₂ were studied by density functional theory systematically. The geometric structure, adsorption energy, molecular dynamics, energy band structure, density of states, charge transfer, and differential charge density of these molecules at five sites of intrinsic Ti₂CO₂, Fe-doped Ti₂CO₂, Zn-doped Ti₂CO₂, FeZn-adjacent co-doped Ti₂CO₂ and FeZn-pair co-doped Ti₂CO₂ were analyzed. The results show that the activity of the substrate can be improved by the introduction of Fe-Zn transition metals. The high adsorption energy of ethanol gas at (A) FeZn site is −1.98eV with the short adsorption distance. The high charge transfer between the metal co-doped Ti₂CO₂ substrate and ethanol gas was also found. The results suggest that the Fe-Zn bimetallic-doped Ti₂CO₂ monolayer may be a potential sensing material for the detection of ethanol gas.

This paper explores the effects of the organic interfacial layer on the electrophysical characteristics of Schottky barrier diodes (SBDs). Three types of SBDs were fabricated: Au-Si (referred to as MS), Au/PVC/Si (referred to as MPS₁), and Au-/PVC:Fe/Si (referred to as MPS₂). Fe nanopowders were subjected to analysis using XRD, SEM, and EDX techniques to investigate their structural and optical characteristics. To investigate the conduction mechanisms of these diodes, I-V characteristics were examined using thermionic-emission (TE), Cheung, and Norde functions. The surface-state density (N_ss) distribution of energy was determined by analyzing the current–voltage (IF-VF) curve under forward bias conditions. This analysis considered the voltage-dependent barrier height (BH) and ideality factor (n(V)). The results demonstrated that the polymeric interlayer without Fe nanoparticles reduced N_ss by a factor of 7, while the presence of Fe nanoparticles led to a two-order magnitude decrease, resulting in improved efficiency in comparison with MS structures. The obtained results indicated that including a polymeric layer in MPS structure enhanced their electrophysical features compared to MS diodes, and significantly increased rectification by 15–45 times. In summary, the existence of an organic interfacial layer significantly altered the conduction mechanisms and electrophysical characteristics of MPS diodes. It was found that the addition of Fe nanoparticles in the interlayer resulted in substantial improvements in N_ss, efficiency, rectification, and conduction characteristics compared to MS diodes.

This paper describes the effects of electronic nonequilibrium in a simulation of ultrafast laser irradiation of materials. The simulation scheme based on tight-binding molecular dynamics, in which the electronic populations are traced with a combined Monte Carlo and Boltzmann equation, enables the modeling of nonequilibrium, nonthermal, and nonadiabatic (electron-phonon coupling) effects simultaneously. The electron-electron thermalization is described within the relaxation-time approximation, which automatically restores various known limits such as instantaneous thermalization (the thermalization time ${\tau }_{e-e}\to 0$) and Born-Oppenheimer (BO) approximation (${\tau }_{e-e}\to \infty$). The results of the simulation suggest that the non-equilibrium state of the electronic system slows down electron-phonon coupling with respect to the electronic equilibrium case in all studied materials: metals, semiconductors, and insulators. In semiconductors and insulators, it also alters the damage threshold of ultrafast nonthermal phase transitions induced by modification of the interatomic potential due to electronic excitation. It is demonstrated that the models that exclude electron-electron thermalization (using the assumption of ${\tau }_{e-e}\to \infty ,$ such as BO or Ehrenfest approximations) may produce qualitatively different results, and a reliable model should include all three effects: electronic nonequilibrium, nonadiabatic electron-ion coupling, and nonthermal evolution of interatomic potential.

Hydrotalcite-like materials such as layered double oxides (LDOs) are promising materials for many technological applications. Linking the multilayer structure of LDOs with the exceptional optical, magnetic, and dielectric properties of spinel ferrites could result in advanced nanocomposites for photovoltaic, magneto-recording, and high-frequency applications. For that purpose, nanocomposites of type manganese chromium-layered double oxide/cobalt spinel ferrite, (MnCr)-LDO_x/CoFe₂O₄ (x = 1, 3, and 5 wt%), were produced by the co-precipitation route. X-ray diffraction (XRD) analysis showed the successful incorporation of MnCr-LDO in CoFe₂O₄ lattice. After a 5 wt% addition of MnCr-LDO, the lattice parameter of pure CoFe₂O₄ increased from 8.3832 Å to 8.4136 Å, the crystallite size increased from 18.7 nm to 21.7 nm, and the strain dropped from 2.15 to 2.04. Transmission electron microscopy (TEM) revealed cubic morphologies for (MnCr)-LDO_x/CoFe₂O₄ nanocomposites. Two strong absorbance peaks appeared in the Ultraviolet- visible (UV-vis) spectra (at ∼270 and ∼370 cm⁻¹). The energy band gap and Urbach energy were estimated for the prepared samples. The composite sample (MnCr)-LDO_{1 wt%}/CoFe₂O₄ recorded the highest band gap values (E_g1 = 3.39 eV, E_g2 = 4.46 eV, and E_g3 = 5.89 eV), while the (MnCr)-LDO_{3 wt%/}CoFe₂O₄ sample had a relatively high Urbach energy value (1.35 eV). Vibrating sample magnetometer (VSM) analysis showed room temperature ferromagnetic (RTFM) behavior for the prepared composites. The saturation magnetization (M_s) value declined as the MnCr-LDO addition to CoFe₂O₄ increased, and the (MnCr)-LDO_{3 wt%}/CoFe₂O₄ sample acquired the highest M_s (64.428 emu g⁻¹) among all the produced composites. Pure CoFe₂O₄ had a much higher coercivity (H_c = 1158.1 Oe) than (MnCr)-LDO_x/CoFe₂O₄ (x = 1, 3, and 5 wt%) nanocomposites (H_c = 1119.8, 978.48, and 984.16 Oe). Moreover, complex impedance spectroscopy measurements were performed in frequency range of 50 Hz- 5 MHz using Nyquist plots and electric modulus analysis. Nyquist plots were fitted to an analogous electric circuit consisting of a resistor R₁ connected in series to two parallel constant phase element- resistor circuits (CPE-R). On the other hand, a different circuit comprises of two CPE, capacitor (C₁), and resistor all connected in parallel was used to model CoFe₂O₄.

Silicon carbide (SiC) is widely used in high-frequency, high-speed, and high-power applications such as power electronics, rail transportation, new energy vehicles, and aerospace. However, the thermal properties of the SiC/SiO₂ interface, which is commonly found in SiC-based devices, are not yet fully understood. This study aims to investigate the influence of temperature and interface coupling strength on the interface thermal resistance (ITR) of 4H-SiC/SiO₂ using non-equilibrium molecular dynamics simulations. Both crystalline and amorphous SiO₂, as well as two interface contact modes (Si-terminated and C-terminated), have also been considered. The results reveal that the ITR of 4H-SiC/SiO₂ is significantly affected by the interface coupling strength and contact modes. Under strong interface coupling conditions, the ITR for Si-terminated and C-terminated contacts modes of 4H-SiC/SiO₂ interfaces are 8.077 × 10⁻¹⁰ m²KW⁻¹ and 6.835 × 10⁻¹⁰ m²KW⁻¹, respectively. However, under weak interface coupling conditions, these values increase to 10.142 × 10⁻¹⁰ m²KW⁻¹ and 7.785 × 10⁻¹⁰ m²KW⁻¹, respectively. Regardless of whether SiO₂ is crystalline or amorphous, the ITR of the 4H-SiC/SiO₂ interface exhibits a similar trend with increasing temperature (from 300 to 700 K). Additionally, the ITR of the amorphous SiO₂ interface is smaller than that of the crystalline SiO₂ interface under both strong and weak coupling conditions. To gain insights into the heat transport mechanism, the phonon density of states was analyzed to examine the phonon spectral characteristics under varying coupling strengths. These findings have implications for enhancing the thermal management and heat dissipation of SiC devices, providing a framework for controlling interface phonon scattering, and informing the thermal design of nanodevices.

This research focuses on the preparation and characterization of TiO₂ thin films in both pure and doped forms. The films were deposited onto glass substrates using the spray pyrolysis technique. The pure film was doped with Cu, Co, and Zn at a constant ratio of 3 wt% in the starting solution. XRD analysis revealed the presence of anatase TiO₂ phase in all deposited films. The crystallite size of the pure film was determined using Scherer's equation and found to be 8.3 nm, while the doped films had sizes of 11.3 nm (Cu), 13.8 nm (Co), and 11.3 nm (Zn). SEM images showed the formation of fine grains with a normal distribution, with average sizes of 27.02 nm (pure), 39.37 nm (Cu), 33.4 nm (Co), and 29.37 nm (Zn) for the respective doped TiO₂ films. EDX analysis confirmed the presence of the dopant elements in the deposited films. It was observed that all films exhibited a direct band gap, with a value of 3.79 eV for the pure film, which slightly decreased upon doping. Additionally, various optical constants such as refractive index, extinction coefficient, dielectric constant, relaxation time, and optical mobility were estimated and presented in this study.

Current–voltage characteristics (EJ curves) and magnetic field dependences of the critical current have been calculated for a superconductor with artificial pinning in the form of submicron-sized holes and tilted radiation defects. Calculations have been performed within the framework of the three-dimensional model of a layered HTS by means of the Monte Carlo method. S-shaped features of the EJ curves have been observed for a sample with a rectangular lattice of holes. Such features have not occurred in calculations for HTSs with non-magnetic pinning centers before, but they have been observed in experimental studies. In this paper, the features occurred in magnetic fields close to 290 Gs (which is the lower critical field for the Bi₂Sr₂CaCu₂O_8-δ superconductor at 1 K) and they were sensitive to the magnitude of the external magnetic field. In addition, the features were more prominent at temperatures below 30 K and in samples with weak intrinsic pinning, and they were connected with matching-like effects in the vortex system (i. e. a certain number of vortices being pinned on each hole, screening new vortices from entering the sample). For samples with tilted radiation defects, decreasing field dependences of the critical current have been obtained, showing weak maxima near the lower critical field of the superconductor. Calculations have shown that, at a fixed value of the external field, the critical current decreases with the increasing tilt angle of the defects.

In the existing studies on the self-propagating high temperature synthesis of titanium nickelide, the main attention has been paid to the study of the influence of heating rate, synthesis start temperature, powder particle size, reaction gas pressure on the structure and properties of NiTi intermetallides. However, the influence of the reactive medium on the formation of surface intermetallic oxynitrides and the properties of the NiTi alloys has not been considered. In the present work, porous titanium nickelide alloys have been obtained by self-propagating high-temperature synthesis in two different reactive atmospheres, argon and nitrogen. The studies show that NiTi-(N) alloys synthesised in the nitrogen reaction atmosphere contain a large amount of brittle secondary Ti2Ni+Ti4Ni2O(N) phases which, in contrast to NiTi-(Ar), are predominantly distributed as small particles. The intergranular Ti2Ni phases in the NiTi-(Ar) alloy synthesised in the argon reaction atmosphere are observed as regions of extensive accumulation of Ti2Ni phase. The reactive nitrogen environment resulted in dispersion of the Ti2Ni phase and lower compressive strength of the porous NiTi-(N) alloy compared to NiTi-(Ar). However, both alloys have a compressive strength greater than human cancellous bone and can be successfully used for intraosseous implantation. At the same time, the porous alloys obtained in different reaction media are passive to electrochemical corrosion and resistant to dissolution in biological media containing chlorine.

Rare-earth magnesium alloys (Mg-RE) are gaining growing prominence across multiple industries due to their superior mechanical properties and enhanced formability compared to conventional magnesium alloys. β' phase of Mg-RE alloys exhibits remarkable behavior in strengthening and enhancing corrosion resistance. However, the mechanical behaviors of some β' phases themselves remain unexplored. Therefore, our objective is to identify the mechanical and thermomechanical properties of β' phases. Herein, a theoretical study to investigate the structural, electronic, elastic and anisotropic properties of β'–Mg₇RE phase from first-principle calculations is described. Besides, the melting temperature and Debye temperature of these intermetallic compounds are also predicted. The calculated results confirm the thermodynamic and mechanical stability of all β'–Mg₇RE phases. Additionally, the calculated value of bulk modulus for all β'–Mg₇RE phase exhibit similarity, with an approximate value of 38 GPa. The degree of anisotropy in the bulk modulus of the β'–Mg₇RE phase is relatively lower compared to the shear and Young's moduli. Among the β' phase, β'–Mg₇Lu exhibits the most pronounced anisotropy. Furthermore, the highest degree of Young's and shear moduli anisotropy for all β' phases are observed in the (001) plane. The value of the electron localization function between Mg and RE atoms ranges from 0.48 to 0.56. In more detail, the density of states (DOS) reveals that hybridization arises from strong interaction between the Mg–p states and RE–d states below the Fermi level. Indeed, the results will offer valuable insights into the influential factors on the mechanical properties of the β' phase, contributing to a more comprehensive understanding of its performance and potential applications.

Polycrystalline lead-free composite ceramics composed of 0.7Bi_1-xSm_xFe_0.95Ga_0.05O₃−0.3BaTiO₃ (BS_xFG-BT) with varying doping concentration of x (0.025, 0.05, 0.10, 0.15, and 0.20) were synthesized. This study comprehensively explores the influence of co-doping Samarium (Sm) and Gallium (Ga) on the microstructures, spectral properties, electrical characteristics, and multiferroic behaviour within the 0.7BiFeO₃−0.3BaTiO₃ system. These composite ceramics exhibited coexistence of R (rhombohedral) and T (tetragonal) phases, characterized by the space groups R3c and P4mm, respectively. The XRD and AFM results show that the Sm and Ga co-doping influenced the crystal structure as well as grain size of BS_xFG-BT ceramics. Raman spectroscopy was used to analyze the positions of the phonon modes. High dielectric constant with high Curie temperature of 550 °C were obtained. The impact of grain and grain boundary on the capacitance and resistance in the ceramics was investigated utilizing Z-view software and high magnitude of bulk resistance was obtained for dopant value x = 0.20 at 300 °C. Enhanced multiferroic properties, remanent magnetisation M_r = 0.051 emu g⁻¹ with coercive field (H_c) = 6450 Oe and remanent polarization P_r = 10.98 μC cm⁻² with coercive filed E_c = 14.73 kV cm⁻¹ were obtained for x = 0.20.

In this article, a sol–gel route was employed to prepare nanophosphor materials including Ca_9−x Cr_xAl (PO₄)₇ series (where 0.05 ≤ x ≤ 0.5 (mol%)). All subseries were irradiated to a γ- test dose of 5 Gy and the thermoluminescence (TL) response of Cr-activated (0.1 mol%) Ca₉Al (PO₄)₇ sample has the best TL response and was chosen for investigations. The phase, particle size, surface morphology, and elemental mapping of the chosen sample Cr_0.1 in comparison with other ones (Cr_0.05 and Cr_0.5) were scrutinized using x-ray diffraction (XRD), transmission electron microscope (TEM), SEM-EDX mapping, and XPS techniques. XRD profiles showed that all diffraction peaks assigned to the trigonal R 3 c space group and the average of particle sizes obtained by the modified Scherer method and TEM data are closely related. The presence of Cr³⁺ ions in the Ca₉Al (PO₄)₇ lattice was assured by XPS spectra. Cr_0.1 chosen sample was studied after irradiation to different γ-doses and displayed a prominent glow curve at 205 °C ± 3.97 °C. It showed a linear dose–response curve from 200 mGy up to 10 Gy with fading of 24% upon 24 h and almost no significant signal loss for further interval times. The average Z_eff value was ∼11 at both 662 and 1250 keV energies making this sample a bone-equivalent material (11.3–11.8). Values of activation energies (eV) calculated by different methods were comparable. Results the dosimetric properties of that the Cr_0.1 sample can be surely considered as an additional recommended detector as other available ones in marketing.

One way to increase the solar cell efficiency is to increase the range of transmitted visible light throughout the window layer. This could be achieved via broadening its band gap; an aim that could be attained through doping and/or irradiation technique. In this way, cadmium sulfide (CdS) thin films have been successfully prepared on pre-heated glass substrates at 400 °C by spray pyrolysis technique and the effect of gamma radiation dose on the structural and optical properties of CdS thin films has been investigated in the range of 250 to 450 Gy. The XRD results manifest the formation of hexagonal phase of CdS with a crystallite size of 58.73 nm, which decreased to 47.26 nm after exposure to 350 Gy. Also, the SEM micrographs show the formation of some randomly oriented groups of nano-rods on the surface of highly condensed nanorods of CdS thin film. The optical investigation illustrates that a blue shift in the optical gap from 2.4 to 3.34 eV has been occurred as the radiation dose reached 350 Gy. The sensitivity of the films to the applied dose has approached 0.005 eV/Gy. Moreover, the shifted band gap exhibited less fading up to 74 days.

In this paper, we fabricated PbZrO₃ (PZ) thin films by the way of sol–gel spin on LaNiO₃ buffered SiO₂/Si substrates, and annealed them at different given temperatures by rapid thermal annealing (RTA). By controlling annealing temperature, PZ thin films showed different microstructures and phase compositions, whose impact of electrical properties and energy storage performance were researched. According to the research findings, the phase composition of film presents a general rule with the decrease of annealing temperature: PZ thin films crystallize into perovskite phase, pyrochlore phase, and amorphous phase. The films annealed at 620 °C crystallized into a state of coexistence of pyrochlore phase and perovskite phases, which also show moderate recoverable energy density and the highest energy storage efficiency (8.7 J cm⁻³ and 93.1%). This energy storage performance can be attributed to the synergistic effect of high electric breakdown strength of dense pyrochlore phase structure and high maximum polarization of perovskite phase. The findings of this paper help to explain the influence of pyrochlore phase on the energy storge performance of thin films. Thus, it is useful way to improve the energy storage performance of thin films.

Antimony selenide (Sb₂Se₃) is a versatile material used in solar cells. The alteration in the physical properties of Sb₂Se₃ alloys on Bi addition has been analysed. (Sb₂Se₃)_100-xBi_x (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2) system has been studied to examine the structural alterations by computing physical parameters. The increase in parameters, i.e., average coordination number 〈Z〉, total number of constraints per atoms (N_c), and crosslinking density (D_cl) reflect an increase in rigidity of the Sb₂Se₃ on Bi incorporation. The computed band gap decreases on Bi addition, from 1.095 eV to 1.079 eV, indicating an approximate increase in absorption wavelength from 1132.42 nm to 1149.21 nm. An increase in rigidity reflects reduction in defect states decreasing the recombination rate within absorption layer. There are variations in cohesive energy, electronegativity, and average single-bond energy. The study reveals that this composition can be utilized to develop novel solar absorber layer materials.

This research article presents an innovative and novel approach to achieve underwater acoustic cloaking using a two-dimensional honeycomb lattice structure with pentamode materials in the kHz frequency range. Underwater acoustic cloaking holds substantial importance in various applications, such as marine engineering, imaging, and military operations, making the development of an efficient underwater acoustic shell imperative. The proposed cloak consists of a pentamode titanium material honeycomb lattice embedded in an air background, submerged in water. To attain effective camouflage and regulate the phase and energy flow, impedance matching was applied to the overall geometry of the structure. By fine-tuning the structural parameters of the cloaking shell, derived from the effective mass velocity and density for recovering reflected waves, impedance matching with water was ensured. Through simulation calculations and optimization design, the average total scattering cross-section of the acoustic cloak is determined to be 0.1. The results demonstrate that the pentamode material-based cloaking approach is not only suitable and efficient in achieving the cloaking phenomenon but also enhances operator flexibility. The operating frequency bandwidth of the acoustic cloaking system is approximately 8 kHz for lattice constant a = 5 mm. These findings pave the way for further advancements in underwater acoustic cloaking technologies.

We investigate the cosine-chirped microwave pulse (cosine CMP)-driven magnetization switching of a nanoparticle or stoner particle at a finite temperature in the framework of the stochastic Landau–Lifshitz-Gilbert equation. Numerical results reveal that the ultrafast and efficient magnetization switching is robust even at room temperature, and hence we estimate the maximal temperature at which the magnetization switching is still valid. The maximal temperature increases with the enlargement (by increasing cross-sectional area) of the nanoparticle/stoner particle volume to a certain value, and afterward, the maximal temperature decreases with the further increment of the nanoparticle size. Initially, the shape anisotropy (approximated by the easy-plane) coefficient does not become dominant although the stoner particle volume increases, which plays a role in increasing thermal stability (maximal temperature), and later the shape anisotropy field becomes dominant, which opposes the uniaxial anisotropy, i.e., reduces the energy barrier, which reduces the maximal temperature. For smaller volumes, the parameters of cosine CMP show a decreasing trend with temperature. The initial frequency requirement significantly decreases with shape anisotropy. Therefore, these findings might be useful to realize cosine CMP-driven fast and energy-efficient magnetization switching in device applications.

This paper examines the process of nucleation in phase field (PF) models, with the aim of elucidating how the use of diffuse interfaces often employed for quantitative modelling of solidification affects nucleation rates and distribution statistics in relation to the predictions of classical nucleation theory. Nucleation is simulated through the use of noise in a quantitative binary alloy PF model using different interface widths. Our results reveal that the rate of nucleation in the PF model is found to be strongly dependent on the scale of the interface width and the numerical discretization, but that careful control of these quantities offers the possibility of a consistent interpretation of nucleation rate. The paper ends by assessing some of the practical merits of seeded versus noise-induced nucleation in PF modelling in the diffuse-interface limit, while also emphasizing how nucleation in this limit is fundamentally flawed from a quantitative perspective.

We conducted a thorough investigation of Cs₂XCuF₆ (X = Sc, Y) using a first-principles approach, exploring a wide range of material properties. We began by confirming the structural and thermodynamic stability of these compounds, employing analyses such as formation energy calculations, examination of the phonon band structure, and the utilization of the Birch-Murnaghan equation of state (EOS) curve. A noteworthy finding was the tunability of the band gaps in these double perovskite materials, achieved by substituting Sc with Y, resulting in a band gap range from 2.67 to 2.62 eV. Our analysis extended to the mechanical stability of these compounds, characterized by elastic constants and revealing mechanical anisotropy and ductility. Additionally, we explored the optical properties, highlighting their broad absorption band from the infrared (IR) to visible regions, which holds significant promise for diverse optoelectronic applications. To provide a comprehensive understanding of these materials, we delved into their thermodynamic properties, encompassing thermal expansion coefficients (κ), heat capacities, entropy (S), volume, and Debye Temperature (θ_D). This investigation spanned a wide pressure range from 0 to 30 GPa and a temperature range from 0 to 1400 K, contributing to a holistic grasp of the fundamental characteristics of Cs₂XCuF₆ (X = Sc, Y).

We include the effects of Sn content $\beta$ in the scaling law to generalize the upper critical field ${B}_{c2}(T,\varepsilon )$ function of temperature and strain in Nb₃Sn. The basis for this generalization comes from a theory developed by the same author [Scientific Reports 7, 1133 (2017)]. The important assumption in the current work is that, in determining the upper critical field ${B}_{c2},$ the contributions of strain, temperature and Sn content are independent of each other. It is followed that we write down a semi-empirical expression ${B}_{c2}(T,\varepsilon ,\beta )={B}_{c2}({T}_{0},{\varepsilon }_{0},\beta )s(\varepsilon )(1-{t}^{1.52})$ where the strain function $s(\varepsilon )$ and $t\equiv T/{T}_{c}(\varepsilon )$ are affected only by strain and temperature, respectively, and the variation of tin content $\beta$ enters in the function ${B}_{c2}$ through ${B}_{c2}({T}_{0},{\varepsilon }_{0},\beta ).$ This separable form of ${B}_{c2}(T,\varepsilon ,\beta )$ allows one to incorporate Sn content $\beta$ in the scaling law in a natural way, while this variable is not considered by traditional scaling laws. In addition to this advance, one can see a more flexible function with triple variables which could be an effective tool to fit or predict experiments. As the last but most important outcome, this semi-empirical function instructs one how to understand the role of component content played in scaling behaviors of Nb₃Sn, so as to reduce the off-stoichiometric composition inducing discrepancy between the results by scaling laws and experiments.

A WC-10Ni/NiCrBSi coating was prepared and applied to the surface of Q235 steel through vacuum brazing. Using a self-developed dry sand abrasion test machine, the effects of the abrasive sand's type, load, and sliding speed on the dry sand abrasion property of the coating were analysed. The wear mechanism of dry sand abrasion was also investigated. The results indicated that the coating cross-section comprised three layers: the substrate, the interface layer, and the surface layer. The hard layer served as the main distribution area of WC hard particles, which directly determined the hardness and wear resistance of the coating. WC particles, fortified by a γ-Ni solid solution, enhanced the wear resistance and hardness of the coating. In the friction and wear test, when ceramic abrasives were employed, the coating sample exhibited a loss of only 23 mg, constituting only 7.9% of that observed with quartz sand abrasives. Under low loading conditions, the wear mass loss exhibited a linear relationship with the applied load. During these low-load scenarios, the abrasive particles operated through a rolling motion, thereby entailing an abrasive wear mechanism. Conversely, when the load exceeded 0.05 MPa, the primary mode of abrasive particle motion transitioned into sliding with burial, resulting in a combination of fatigue wear and abrasive wear mechanisms. Therefore, the dry sand abrasion mechanism inherent to composite coatings can be attributed to the protective shielding role played by WC particles on the substrate. This shielding function effectively mitigates and counteracts the abrasive cutting effects induced by abrasive particles.

The velocity field composed of the Berry connection from many-body wave functions and electromagnetic vector potential explains the energy-momentum balance during the reversible superconducting-normal phase transition in the presence of an externally applied magnetic field. In this formalism, forces acting on electrons are the Lorentz force and force expressed as the gradient of the kinetic energy. In the stationary situation, they balance; however, an infinitesimal imbalance of them causes a phase boundary shift. In order to explain the energy balance during this phase boundary shift, the electromotive force of the Faraday's magnetic induction type is considered for the Berry connection. This theory assumes that supercurrent exists as a collection of stable quantized loop currents, and the transition from the superconducting to normal phase is due to the loss of their stabilizations through the thermal fluctuation of the winding numbers of the loop currents. We argue that an abrupt change of loop current states with integral quantum numbers should be treated as a quantum transition; then, the direct conversion of the quantized loop currents to the magnetic field occurs; consequently, the Joule heat generation does not occur during the phase transition.

Detailed heat capacity and birefringence measurements have been performed to investigate the transitional behavior near the orthogonal smectic-A to tilted smectic-C (Sm-A–Sm-C) phase transition on several liquid crystalline mixtures comprising of a rod-like mesogen and a hockey stick-shaped compound having substitution of methyl group in the lateral position. Both probing methods were found to be rather successful in assessing the phase transitional behavior with reasonably good accuracy. The data shows a divergent pretransitional excess above and below the transition temperature. Analysis of the data have been performed in detail with the renormalization-group expression with correction-to-scaling terms. The extracted effective critical exponents were observed in between the tricritical and 3D-XY limit. Detailed investigations carried out in this work reveal the dependence of the Sm-A–Sm-C phase transition on the width of the Sm-A phase and the existence of a broad tricritical range.

Hydrothermally synthesized nano multiferroic SrBi_2-X(CF)_XNb₂O₉ (SBN-CF), (CF = CoFe₂O₄ & X = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) composite's structure correlated magnetic attributes in view of reaction, exchange, and transport of ions have been comprehended from the perspective of electronic sector applications. The produced materials' phase genesis, morphology, chemical composition, and magnetic characteristics were studied by XRD/Rietveld analysis, FEGSEM/EDS, FTIR, and VSM respectively. The Rietveld analysis of XRD data confirmed a single-phase orthorhombic structure of SBN. Further ferroelectric and cubic spinel structures of the ferrite phase have been noticed from the introduction of CF into the SBN host matrix. The crystallite size as computed (∼23–41 nm) from Debye Scherer's formula was found to increase with dopant concentration. The imbibed morphological changes necessitated octahedral-shaped grains. The stoichiometric proportion with pronounced absorption bands is evident in EDS and FTIR studies. The impact of CF on SBN was unraveled at room temperature from the VSM study. The saturation magnetization was increased from 0.00 to 3.96 emu g⁻¹, and the obtained coercivity values enhanced from 0.50 to 1400 Oe, due to the random fluctuations of the energy due to domain wall movements, interacting with the defective structure of the SBN material. The stress-induced distortion due to the variation in concentration of CF in SBN was configured from Y-K angles and increased from 33.55° to 61.49°. The high coercivity with a squareness value of less than 0.5 enunciates the genesis of a new class of materials for use in permanent magnet applications and memory devices.

In this study, a Q-switched Nd:YAG laser with specific parameters, including a pulse repetition rate of 6 Hz, a pulse duration of 10 nm, a wavelength of 532 nm, and a laser fluence of 237.47 J cm⁻¹², was employed to fabricate highly crystalline TiO₂ nano-films. These nano-films exhibited a narrow energy band gap of 3.24 eV and showcased favorable surface morphology, characterized by a roughness of 2.38 nm. A solar cell device was produced by creating porous silicon (PSi) and applying titanium dioxide films onto the PSi, achieving a notable conversion efficiency of 8.733%. To investigate the impact of different parameters on the resulting TiO₂ nano-films, a range of laser fluences (ranging from 131.93 to 263.85 J cm⁻¹²) and three distinct laser wavelengths (1064 nm, 532 nm, and 355 nm) were employed during the pulsed laser deposition (PLD) process. These experiments aimed to grow TiO₂ films on both quartz and silicon (Si) substrates.