Table of contents

The narrow frequency bandwidth and the effective frequency which cannot be low enough are two major challenges in underwater acoustics. To overcome these drawbacks, a new eccentric resonance matching layer with anti-reflection characteristics is proposed for underwater acoustic scattering suppression. Homogenization method and anti-reflection theory are applied for the design of anti-reflection structure. The complete mathematical model is developed based on the finite element method (FEM). Numerical simulations are carried out by COMSOL to verify the accuracy of the mathematical model. The results show that the proposed matching layer can significantly improve the broadband absorption capacity and can effectively suppress underwater acoustic scattering, especially at relatively low frequencies. It is a breakthrough in underwater low-frequency acoustic absorption, indicating that the structure has application prospects in underwater acoustic stealth, acoustic energy dissipation and acoustic wave regulation.

In this paper, we formulate black hole solutions through extended gravitational decoupling scheme in the framework of self-interacting Brans-Dicke theory. The addition of a new source in the matter distribution increases the degrees of freedom in the system of field equations. Transformations in radial as well as temporal metric functions split the system into two arrays. Each array includes the effects of only one source (either seed or additional). The seed source is assumed to be a vacuum and the corresponding system is specified through the Schwarzschild metric. In order to construct a suitable solution of the second system, constraints are applied on the metric potentials and energy-momentum tensor of the additional source. We obtain three solutions corresponding to different values of the decoupling parameter in the presence of a massive scalar field. The extra source is classified as normal or exotic through energy conditions. It is found that two solutions agree with the energy bounds and thus have normal matter as their source.

In this paper, we presented an overview diagnosis consider the time series of daily deaths by COVID-19 in the Brazilian States using Bandt & Pompe method (BPM) to estimate the Information Theory quantifiers, more specifically the Permutation entropy (H_s) and the Fisher information measure (F_s). Based on the Information Theory quantifiers, we build up the Shannon-Fisher causality plane (SFCP) to promote insights into the COVID-19 temporal evolution inherent in the phenomenology associated with the number of daily deaths well as their respective locations along the SFCP. Moreover, we apply H_s and F_s to elaborate on the rank of the Brazilian States' real situation, considering the number of daily death due to COVID-19 based on the complexity hierarchy. The Brazilian States that are located in the middle region of the two-dimensional plane (H_s x F_s), such as Amapá (AP), Roraima (RO), Acre (AC), and Tocantins (TO) are characterized by a less entropic and low disorder, which implies in high predictability of the COVID-19 lethality. While, the Brazilian States that are located in the lower-right region, such as Ceará (CE), Bahia (BA), Pernambuco (PE), and Rio de Janeiro (RJ), are characterized by high entropy and high disorder, which leads to low predictability of the COVID-19 lethality. Given this, our results provide empirical evidence that the permutation entropy is a powerful approach to predicting infectious diseases. Dynamic monitoring of permutation entropy can help policymakers to take more or less restrictive measures to combat COVID-19.

Measuring gloss, visually or instrumentally, has been a challenge in many manufacturing and service industries. However, there exists no standardized method for visual evaluation of equidistance specular gloss. This study aimed to design and prepare a psychometric visually equispaced specular gloss scale for the visual measurement of gloss or any other geometric appearance attribute. To this end, a series of lithographically printed black papers, with different levels of gloss from low to high, were prepared to constitute a visually uniform specular gloss scale. Fourteen observers visually quantified the scale in a unidirectional illumination at three different geometries. Analyzing the results shows that the 60° geometry can quantify the equivalent specular gloss efficiently. A uniform specular gloss scale was prepared by assessing the prepared scale visually under the unidirectional illumination at the 60° geometry. Such a visually uniform specular gloss scale could be employed to develop a standard visual evaluation method of specular gloss in all related industries.

Based on the infinite dimensional variable quantum system, we propose two quantum algorithms to solve the linear equations. Both algorithms can be considered as infinite-dimensional versions of the HHL algorithm. From this we can see that the infinite dimensional quantum variable system as a physical resource can be widely popularized in quantum computing.

Developing a scalable quantum computer as a single processing unit is challenging due to technology limitations. A solution to deal with this challenge is distributed quantum computing where several distant quantum processing units are used to perform the computation. The main design issue of this approach is costly communication between the processing units. Focused on this issue, in this paper, an efficient partitioning approach is proposed which combines both gate and qubit teleportation concepts in an efficient manner to minimize the communication. Experimental results show the proposed approach on average reduces the communication cost by about 29.5% in comparison with the best approaches in the literature.

Non-classical states are of practical interest in quantum computing and quantum metrology. These states can be detected through their Wigner function negativity in some regions. We show that the surfaces of minimum fidelity or maximum Bures distance constitute a signature of quantum phase transitions. Additionally the behaviour of the Wigner function associated to the field modes carry the information of both, the entanglement properties between matter and field sectors, and the regions of the parameter space where the quantum phase transitions take place. A finer classification for the continuous phase transitions is obtained through the computation of the surface of maximum Bures distance.

A general procedure is established to calculate the quantum phase diagrams for finite matter-field Hamiltonian models. The minimum energy surface associated to the different symmetries of the model is calculated as a function of the matter-field coupling strengths. By means of the ground state wave functions, one looks for minimal fidelity or maximal Bures distance surfaces in terms of the parameters, and from them the critical regions of those surfaces characterize the finite quantum phase transitions. Following this procedure for N_a = 1 and N_a = 4 particles, the quantum phase diagrams are calculated for the generalised Tavis-Cummings and Dicke models of 3-level systems interacting dipolarly with 2 modes of electromagnetic field. For N_a = 1, the reduced density matrix of the matter allows us to determine the phase regions in a 2-simplex (associated to a general three dimensional density matrix), on the different 3-level atomic configurations, together with a measurement of the quantum correlations between the matter and field sectors. As the occupation probabilities can be measured experimentally, the existence of a quantum phase diagram for a finite system can be established.

Several schemes for bidirectional controlled quantum teleportation (BCQT) of arbitrary single-qubit states have been proposed by utilizing five-qubit entangled states, six-qubit entangled state and seven-qubit entangled state as the quantum channels. In this paper, a generalization to BCQT of multi-qubit entangled states is presented. By using a five-qubit entangled state as the quantum channel, we propose a scheme for BCQT of certain class of multi-qubit entangled states in which two legitimate users exchange their unknown multi-qubit entangled state to each other with the help of a supervisor. Compared with previous BCQT (3 ↔ 3) scheme [2019 Int. J. Theor. Phys. 58 3594], our proposed BCQT (m ↔ n) scheme requires less consumption of quantum and classical resources, and possesses higher intrinsic efficiency. Also, the present BCQT scheme is more general and has less operation complexity.

The absorption coefficients, refractive/group indices, phase shifts and fractional change of birefringence beams through dynamic chiral atomic medium are investigated under the effect of quantum tunnelling. The birefringence of phase indices ${\rm{\Delta }}n={n}_{r}^{(+)}-{n}_{r}^{(-)}$ and group indices ${\rm{\Delta }}{n}_{g}={n}_{g}^{(+)}-{n}_{g}^{(-)}$ are controlled and modified through induced dynamic chiral medium by tunnelling effect. The group indices ${n}_{g}^{(\pm )}=\pm 500$ and group velocities ${v}_{g}^{(\pm )}=\pm c/500$ are reported with the tunnelling effect. The maximum change in birefringent phase shifts is calculated to 5 microradian with tunnelling frequency at a speed of v = 10 cm/s of the chiral medium in the right circularly polarized (RCP) and left circularly polarized (LCP) beams. A 60% fractional change in the phase shift of RCP and LCP beams are investigated through induced chiral medium when the medium is at rest and when it is moving with the speed of v = 10 cm/s. These results will play an important role in scatterplate phase shifting interferometry.

The proposal of the quantum teleportation(QT) is to transfer an unknown quantum state from one place to another through local operations and classical communication. However, the efficiency of standard QT will be significantly reduced due to the influence of the inevitable noise in environments. In this work, we propose two schemes to improve the efficiency of the QT protocol when quantum channel is subjected to bit-flip or phase-flip noise. We find that the so-called more entanglement means low efficiency in the performance of the standard teleportation protocol, and the optimal fidelity is obtained only by using the appropriate unitary operation. Specially, we show that the optimal averaged fidelity to our schemes is always more than the best classically achievable fidelity 2/3. We also provide a physical explanation of the obtained conclusions and our results will be helpful for improving quantum communication with real implementation.

In this paper, we present a theoretical study of Autler-Townes (AT) splitting, electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA) phenomena in a four-level ladder (Ξ)-type configuration formed by two coupling and one probe laser fields using density matrix formalism in dressed state representation (DSR). The DSR is followed by the analytical solution of the optical Bloch equations (OBEs) under density matrix formalism in bare state representation (BSR). The density matrix elements are presented in both linear and non-linear interaction regimes under DSR. The concept of transfer of population (TOP) mechanism has been shown by calculating the different transition probabilities in DSR. It has been found that the population in a particular dressed state is greatly enhanced by increasing the strength of coupling field and played a key role to manipulate the induced coherence between different energy levels. The present theoretical model of DSR offers an excellent interpretation of the formation of EIT, EIA and conversion from EIT to EIA in both linear and third order non-linear probe absorption profiles. Besides, the dispersion profiles in both linear and non-linear interaction regimes have also been studied and the conversion of normal to anomalous dispersion profile which drastically modifies the optical responses of the medium has been discussed. We have found that the amplitudes of the coherent signals are more sensitive to the third order non-linear interaction compared to first order linear interaction.

This investigation is addressed to examine the comparative consequence of thermal radiation and heat generation/absorption in steady three-dimensional MHD (Magneto-hydrodynamics) stagnation point flow of (MWCNTs + Cu/engine oil) hybrid nanofluid over a porous circular cylinder. Flow via thermal slip effect is inspected. Also, the impact of both homogeneous/heterogeneous (h–h) chemical reactions are considered for explanation of mass transportation characteristics. Here, a kind of hybrid nanofluid including MWCNTs (multi wall carbon nanotubes) and Cu(Coper) nanoparticles with engine oil as base fluid is used. Appropriate transformation procedure is implemented for renovating model expression of continuity, momentum, energy, mass transportation and boundary conditions into a set of ODEs. HAM (Homotopy Analysis Method) methodology is then employed to solve these nonlinear coupled ODEs. Furthermore, the influence of inserting model factors on velocities, temperature fields, C_f (skin friction coefficient) and Nu (Nusselt number) has been investigated numerically and graphically. The core outcome specifies that hybrid nanofluid (MWCNTs + Cu + engine oil) improve thermal conductivity when equated with nanofluid (MWCNTs + engine oil).

A (2+1)-dimensional completely generalized Hirota-Satsuma-Ito equation is studied. Based on the Hirota bilinear method, multi-kink solutions are obtained. The higher-order lump solutions are obtained by the long-wave limit approach. By selecting the complex conjugate parameters conditions for multi-kink solutions, the multi-breather solutions are constructed. Moreover, ten kinds of interaction solutions consisted of three waves for kink, breather and lump are obtained. Some dynamical behaviors of the solutions obtained in the paper are shown by figures.

Analysis of magneto-hydrodynamic flow of classical non-Newtonian fluid, Reiner-Philippoff fluid, over magnetized plate is conducted numerically in this article. The mathematical model incorporates the non-linear stress deformation behavior of Reiner-Philippoff fluid and set of Maxwell's equations to discuss the behavior of non-Newtonian fluid in a magnetic field. Boundary layer equations are obtained assuming the Reynolds and magnetic Reynolds numbers to be large enough for magnetic and momentum boundary layers to have developed. The correlation expressions for skin friction and magnetic flux on the surface for different flow and magnetic field parameters are developed by performing linear regression on numerical data. Stability analysis is conducted as well to analyze the effects of magnetic field and fluid nature on the stability of the flow.

A novel soliton solution of the famous 2D Ginzburg-Landau equation is obtained. A powerful Sine-Gordon expansion method is used for acquiring soliton solutions 2D Ginzburg-Landau equation. These solutions are obtained with the help of contemporary software (Maple) that allows computation of equations within the symbolic format. Some new solutions are depicted in the forms of figures. The Sine-Gordon method is applicable for solving various non-linear complex models such as, Quantum mechanics, plasma physics and biological science.

We study various regimes of coherent coupled motion of a polaron and one-dimensional Bose–Einstein condensate in a harmonic potential. By using qualitative analysis, perturbation theory and direct numerical solution of the Gross–Pitaevskii equation, we show that the entire dynamics is strongly nonlinear and critically depends on the sign of the self-interaction in the condensate and the sign of the interaction between the polaron-forming embedded particle and the condensate. Strongly mutually related evolution of the condensate shape, its center of mass position, and polaron coordinate is studied for coupled nonlinear polaron-condensate oscillations and transmission/reflection of the polaron through/by the condensate.

The present paper computationally examines the w-shaped solitary wave solutions for an important type of nonlinear Schrödinger equation that appeared in 1979 called the Chen-Lee-Liu (CLL) equation by proposing two recursive schemes. The schemes are based on the famous Adomian's efficient decomposition technique. We successfully simulated the two proposed schemes with the aid of mathematical software and established a comparative analysis. It is noted from the present study that the improved method performs better than the classical method at different time levels. This is in fact in conformity with most of the results in the related literature. We finally present tables and a series of figures to support the presented results.

This paper investigates the accuracy of three recent computational schemes (the extended simplest method (ESEM), sech—tanh expansion method (STEM), and modified Kudryashov method (MKM)) through calculating the absolute value of error between their solutions and numerical solutions. The computational schemes claim to obtain exact traveling wave solutions of the investigated models; therefore, it supposes the numerical study for any models that have been analytically investigated under any constructed computational solutions that will be matching, but our study shows a different fact. (Khater et al Soft Computing (Submitted)) has studied the computational solutions of the time-fractional Lotka—Volterra (LV) model through the above-mentioned computational schemes. Many solutions have been obtained in different mathematical formulas such as exponential, trigonometric, hyperbolic, etc. These solutions describe the interaction between the high -frequency Langmuir and the low-frequent ion-acoustic waves with many applications in electromagnetic waves, plasma physics, and signal processing through optical fibers, coastal engineering, and fluid dynamics. This manuscript applies the trigonometric quintic B—spline scheme to the fractional LV model along with the Caputo and Fabrizio fractional derivatives and computational obtained solutions for investigating the numerical solutions under each employed analytical scheme. The numerical solutions are simulated in two-dimensional sketches to explain the relation between exact and numerical solutions. This study proves the computational fact hypotheses for obtaining exact solutions, and they all obtain computational solutions.

The intention of the current flow model is to investigate the significance of bioconvection in stagnation point flow of third grade nanofluid containing motile microorganisms past a radiative stretching cylinder. The impacts of activation energy and stagnation point flow are also considered. In addition the behavior of thermophoresis diffusion and Brownian motion are observed. Nanofluid can be developed by dispersing the nanosized particles into the regular fluid. Nano-sized solid materials for example carbides, grephene, metal and alloyed CNT have been utilized for the preparation of nanofluid. Physically, regular fluids have low thermal proficiency. Therefore, nano-size particles can be utilized to enhance the thermal conductivity of the host fluid. Nanofluids have many features in hybrid power engine, heat transfer, and can be used in cancer therapy and medicine. The formulated system of flow problems are transformed into dimensionless coupled ordinary differential expressions system via appropriate transformation. The systems of converted governing expressions are computed numerically by employing well known bvp4c solver in MATLAB software. The outcomes of emerging physical flow parameters on the velocity profile, volumetric concentration of then nanoparticles, rescaled density of the motile microorganisms and nanofluid temperature are elaborated graphically and numerically. Furthermore, velocity of third-grade fluid intensifies for higher values of third-grade fluid parameter and mixed convection parameter while opposite behavior is detected for buoyancy ratio parameter and mixed convection parameter. Temperature distribution grows for higher estimation of temperature ratio parameter and Biot number. Higher amount of Prandtl number and Lewis number decreases the concentration of nanoparticles. Concentration of microorganisms reduces by growing the values of velocity ratio parameter and bioconvection Lewis number.

This paper proposes a fractional-order cellular neural network (CNN) chaotic system for image encryption algorithm to explore the application of fractional-order CNN hyperchaotic system in chaotic secure communication. Firstly, a fractional-order CNN hyperchaotic system is defined based on CNN hyperchaotic system. The numerical solutions of the fractional-order CNN hyperchaotic system are calculated by Adomian decomposition algorithm. The dynamic characteristics of the of the fractional-order CNN hyperchaotic system are analyzed. Then to verify the image encryption application of the fractional-order CNN hyperchaotic system, we designed an image encryption scheme through fractional-order CNN hyperchaotic sequence, the principle of symmetry of main diagonal of matrix and XOR operation. Finally, the results illustrate that the fractional-order CNN hyperchaotic sequence has good randomness, which show that the fractional-order CNN hyperchaotic system more suitable for chaotic secure communication applications. The security performances of the algorithm show that the designed algorithm can effectively encrypt and decrypt image, and has better security performance.

An incompressible flow of Casson-Maxwell fluids over stretchable disk rotating with constant angular speed is demonstrated in this research. Buongiorno theory of nanomaterials is utilized in the flow model to reveals the impacts of Brownian movement and thermophoresis. Cattaneo-Christov heat diffusion theory along with variable thermal conductivity is elaborated in the energy equation. The convective boundary condition for thermal analysis is imposed at the disk surface. The governing equations are normalized by means of similarity functions. Numerical approach is adopted to solve the complex non-linear system by Runge–Kutta-Fehlberg (RKF) procedure. The influence of dimensionless variables on velocity, thermal and concentration fields is illustrated through graphs, while the numerical values of thermal and concentration rates are explained in tabular way.

The response function and largest Lyapunov exponent analysis were applied to the driven overdamped Frenkel-Kontorova model with two types of anharmonic convex interparticle potentials. In both cases model reduces to a single particle model for integer values of winding number. It is shown that the mirror image of the amplitude dependence of critical depinning force and largest Lyapunov exponent observed recently in the standard Frenkel-Kontorova model (Odavić et al 2017 Commun. Nonlinear Sci. Numer. Simul.47, 100) is not retained generally. Behaviour of systems with relatively strong interparticle force was examined and evidence for the appearance of mode-locking phenomenon in both directions of particles' motion is presented.

Optimization for all disciplines is essential and relevant. Optimization has played a vital role in industrial reactors' design and operation, separation processes, heat exchangers, and complete plants in Chemical Engineering. In this paper, a novel hybrid meta-heuristic optimization algorithm which is based on Differential Evolution $(DE),$ Gradient Evolution $(GE),$ and Jumping Technique (+) named Differential Gradient Evolution Plus (DGE+) is presented. The main concept of this hybrid algorithm is to enhance its exploration and exploitation ability. The proposed algorithm hybridizes the above-mentioned algorithms with the help of an improvised dynamic probability distribution, additionally provides a new shake off method to avoid premature convergence towards local minima. The performance of $DGE+$ is investigated in thirteen benchmark unconstraint functions, and the results are compared to the other state-of-the-art meta-heuristics. The comparison shows that the proposed algorithm can outperform the other state-of-the-art meta-heuristics in almost all benchmark functions. To evaluate the precision and robustness of the $DGE+$ it has also been applied to complex chemical dynamic optimization systems such as optimization of a multimodal continuous stirred tank reactor, Lee-Ramirez bioreactor, Six-plate gas absorption tower, and optimal operation of alkylation unit, the results of comparison revealed that the proposed algorithm can provide very compact, competitive and promising performance overall complex non-linear chemical design problems.

The foremost aim of our study is to discuss the unsteady 2D MHD Powell-Eyring flow produced by a flat stretching surface. An incompressible chemical reactive MHD Eyring- Powell fluid immersed in porous medium filled the convective heated stretched sheet with the appearance of nanoparticles. A thorough in- vestigation is performed to study impacts of exothermic, first order chemical reactions and thermal radiation on the fluid flow. This study also assesses the heat and mass boundary conditions. The model utilized for nanoliquid elaborates the influence of thermophoresis and Brownian motion. Moreover, an efficient finite difference method is used and a numerical solution is obtained for the resulting nonlinear PDEs with appro- priate boundary conditions. A detailed discussion regarding how the principal variables affects the flow and thermal fields, is carried out. It is also discussed that how the flow and heat transfer processes is affected by the various parameters of interest. In addition to all this, the physical quantities such as Nusselt number, drag coefficient and mass transfer are calculated keeping in view their significance in engineering.

The significance of semi-linear parabolic equations in various fields of physics and chemistry is perpetual. Literature is enriched with the modeling and numerical investigations of their various paradigms. In this paper, a class of semi-linear diffusion equations is considered as prototypical semi-linear parabolic equation. The equations are reformulated to fractional order derivative by applying Caputo-Fabrizio time fractional derivative (CFTFD). Moreover, an amalgamated technique, that is, a semi-analytical technique is also established, which is combination of Laplace transform and Picard's iterative method (LTPIM). Specifically, it is designed to effectively simulate the governing semi-linear diffusion equations. In addition, the stability analysis of this amalgamated technique is also carried out through comparison with Banach fixed point theorem and H-stable mapping. The obtained results are illustrated graphically and in tabulated form, which evidently validates the proficiency of this technique for semi-linear parabolic equations.

The focus of this paper is to examine non-similar solutions of dusty non-Newtonian Casson nanofluid flow around the surface of an isothermal sphere in the presence of magnetic field impact. It is presupposed that the impacts of thermophoresis and Brownian motion are considered into regard in the nanofluid model. In addition to the thermophoresis impact, the normal flux of nanoparticles is equal to zero at the boundary. With respect to the fluid temperature, the surface of the isothermal sphere is preserved at a constant temperature. The dust particles preassumed to having the same size and conform in the spherical shape to the nanoparticles. Suitable non-similarity transformations are utilized to mutate the governing partial differential equations for fluid and dust phases into a system of non-linear, coupled, and non-similar partial differential equations. The generated non-similar equations are solved using numerical technique renown MATLAB function bvp4c and the results are represented in terms of velocity and temperature of fluid and dust phases, and concentration distribution as well as the skin-friction coefficient and heat transfer rate. Obtained results indicate that increasing the mass concentration of the dust particles in the nanofluid leads to depression the motion and an enhancement in the rate of heat transfer. For the nanofluid phase and dust particle phase, the temperature magnitude improves with increasing of the stream wise coordinate additionally the distribution of velocity accelerates away from the sphere surface i.e. with high values of the radial coordinate η.

The present study explores the influences of chemical reaction and viscous dissipation on the hydromagnetic squeeze flow of Jeffrey fluid in channel over porous medium by slip boundary. The nonlinear partial differential equations are converted to the nonlinear ordinary differential equations using dimensionless variables and solved through numerical approach of Keller-box. The results of skin friction coefficient, Nusselt and Sherwood numbers are compared with existing results in the journal for validation of the present results. Comparison shows that the numerical outputs are in excellent agreement. Findings indicate that wall shear stress and fluid velocity increase as the plates approaching each other. Also, increment of Hartmann number (from 0.5 to 6.5) and ratio of relaxation and retardation times decrease the velocity, temperature and concentration profile. The effect of viscous dissipation elevates the heat transfer rate and temperature profile. Besides, mass transfer rate drops in convective chemical reaction and opposite impact is noticed in destructive chemical reaction.

In this work, by using the Hirota bilinear method, we obtain one- and two-soliton solutions of integrable (2 + 1)-dimensional 3-component Maccari system which is used as a model describing isolated waves localized in a very small part of space and related to very well-known systems like nonlinear Schrödinger, Fokas, and long wave resonance systems. We represent all local and Ablowitz-Musslimani type nonlocal reductions of this system and obtain new integrable systems. By the help of reduction formulas and soliton solutions of the 3-component Maccari system, we obtain one- and two-soliton solutions of these new integrable local and nonlocal reduced 2-component Maccari systems. We also illustrate our solutions by plotting their graphs for particular values of the parameters.

In this paper, based on the principle of activation function between the neurons, we designed a Hopfield neural network (HNN) chaotic system. And then we defined a fractional-order HNN chaotic system by Caputo definition. The solution of the fractional-order HNN chaotic system is calculated by Adomain decomposition method (ADM). Then the dynamic performances of the fractional-order HNN chaotic system are analyzed through attractor phase diagram, bifurcation diagram, Lyapunov exponent spectrum, fractal dimension, chaotic diagram and SE complexity. In addition, the system is digital circuit implemented based on DSP platform. The experimental results show that the fractional-order HNN chaotic system not only has rich dynamic behavior, but also has complex nonlinear phenomena such as attractor coexistence which is sensitive to initial value. Therefore, this system has good potential application value, it can be used as multi-source pseudo-random number generator, and the generated pseudo-random sequence can be used in chaotic cryptography and secure communication.

A numerical approach is adopted to explore the analysis of combined convection and thermal radiation on molecular theory of liquid originated nanofluid over an extendable surface. The temperature-dependent viscosity is considered through Vogel's and Renold's model. The physical problem gains more significance in the presence of temperature-dependent thermal conductivity. Nanofluid attributes are explored through thermophoresis and Brownian motion effect. Radiative heat flux is also taken into account to study the thermal radiation aspects. Characteristics of sundry physical parameters on the velocity, thermal energy and mass transfer are computed numerically and graphically. Velocity pattern expands for growing the size of thermophoresis diffusion and decline by the expanding amount of fluid parameter for Vogel's and Renold's model. Temperature fluctuation rises when the quantity of variable thermal conductivity parameter getting up and falls for radiation parameter. Concentration curve increases if the values of Prandtl number enlarge for Renold's model. Concentration boundary layer thickness declines for inclining in Brownian diffusion, radiation and Prandtl number for Vogel's model.

This work presents a novel methodology to analytically solve the stationary Schrödinger equation in presence of a couple of two-dimensional semi-infinite rectangular potential barriers, when the incident wave is a finite-width monoenergetic wave packet. Such methodology does not depend at all on the incident wavefront of the packet and is based on the transfer-matrix method, but unlike the latter, our transfer matrix is built partly in real space and partly in Fourier space. A spectrum of angular plane waves is used to represent the incident, reflected and transmitted beams. As a particular case, we study the transmission of Hermite-Gaussian wave packets through the barrier system. A detailed analysis of the transmission coefficient is carried out as a function of both the parameters of the incident beam (which in turn are directly related to the shape of the incident packet) and the parameters of the barriers. We also briefly discuss the behavior of the probability density of three transmitted beams.

This paper introduces a new hyperchaotic oscillator base on a new boundary-restricted Hewlett-Packard memristor model. Firstly, the complex system is designed based on a memristor-based hyperchaotic real system, and its properties are analyzed by means of Lyapunov exponents, Lyapunov dimension and phase portraits diagrams. Secondly, a simple feedback control based on the minimum variance control technique is designed to stabilize the hyperchaotic oscillator system, which is one of the new developed approaches for controlling the chaos in high-dimensional hyperchaotic systems. In this method, the time series variance is considered for designing and calculating the state feedback control gain. Furthermore, the state feedback control is designed so that to minimize the variance as a cost function, followed by developing an online optimization technique using the particle swarm optimization method in order to calculate the state feedback control based on the minimum variance strategy. Then, the application of this method is examined on a hyperchaotic memristor-based oscillator. Finally, the sensitivity of the proposed method is evaluated in different initial conditions that greatly influence the hyperchaotic dynamics. Considering that the optimization is online, simulation results show highly good effectiveness of the presented technique in controlling the chaos in high-dimensional hyperchaotic oscillators

This article analyzes the growth of the vapor bubble in a novel model of power-law nanofluids (Al₂O₃/H₂O) under a new effect of variable surface tension. The governing equations of the rising vapor bubble flow model are formulated and converted to a single equation describing the bubble dynamics behavior. By employing the model of Plesset and Zwick method, we investigate a new model of equations within power-law nanofluids to examine the effect of different physical parameters such as initial superheating liquid, critical bubble radius, and thermal diffusivity on the vapor bubble formation. Furthermore, the effects of surface tension behavior with the initial bubble radius, time, and initial rate of bubble radius are examined. It is found that the growth of the vapor bubble radius increases with the increase of initial superheating liquid, critical bubble radius, and thermal diffusivity. In addition, the connection between shear stress and shear rate is analyzed in detail. Using appropriate values for the physical parameters, the behavior of solutions of the vapor bubble is discussed. Based on the conducted simulation analysis, the behavior of the solutions is found to be more accurate than those in the previous studies. Besides, the obtained results demonstrate that the vapor bubble in power-law nanofluids grows slower than in pure water.

In this paper, the Haar wavelet discretization method (HWDM) is proposed for the calculation of natural frequency of the laminated composite conical-cylindrical coupled shells. The displacement components of the system are set by the first order shear deformation shell theory (FSDST), and all the displacement functions of conical and cylindrical shells including boundary conditions are obtained by the Haar wavelet and its integrals. The Hamilton's principle is applied to the constitution equation and the artificial spring technique is introduced to generalize the boundary and continuity conditions of the coupled structure. The convergence and accuracy of the proposed method are validated by comparing with the results obtained from the previous works and finite element analysis, and the proposed method shows high accuracy, reliability and good convergence in both individual structure and coupled structure. Using the proposed method, in the laminated composite conical–cylindrical coupled shell with any boundary condition, new numerical results on the natural frequency are obtained along with the parameter studies, and these results can provide the referential data for the following research in this field.

Here, the Deoxyribo-Nucleic Acid (DNA) dynamic equation that arises from the oscillator chain named the Peyrard-Bishop model for plenty of solitary wave solutions is presented. The efficacy of newly designed algorithms are investigated, namely, the extended Auxiliary equation method and Kudryashov expansion method for constructing the new solitary wave solutions of the DNAdynamic Peyrard-Bishop model with beta-derivative. Here, the proposed methods contribute to a range of accurate solutions for soliton, including light, dark, and other solutions are obtained. In addition, some results are also clarified by computer simulations demonstrating the uniqueness of our work relative to the existing literature on the classic Peyrard-Bishop model. These solutions lead to the issue of the possibility to expand the method to deal with other non-linear equations of fractional space-time derivatives in non-linear science. It is noted that the newly proposed approach is accurate and is used to create new general closed-form solutions for all other fractional NPDEs.

We study dynamics of soliton waves, lump solutions and interaction solutions to a (2+1)-dimensional generalized Bogoyavlensky-Konopelchenko equation, which possesses a Hirota bilinear form. Multi-soliton solutions, one-M-lump solutions, and physical interactions between solitons and 1-M-lump solutions are presented. By using a positive quadratic function, lump solutions and their interaction solutions with kink and solitary waves are also generated. To show dynamical properties and physical behaviors of the resulting solutions, 3D-plots and contour plots at different times are made and analyzed.

Exploring new wave soliton solutions to nonlinear partial differential equations has always been one of the most challenging issues in different branches of science, including physics, applied mathematics and engineering. In this paper, we construct multiple rogue waves of (3+1)-dimensional Korteweg–de Vries Benjamin-Bona-Mahony equation through a symbolic calculation approach. Further, a detailed analysis of the localization features of first-order rogue wave solution is also presented. We discuss the influence of the parameters in the equation on the localization and characteristics of a rogue wave, as well as the control of their amplitude, depth, and width. In order to achieve these desired results, a series of polynomial functions are utilized to construct the generalized multiple rogue waves with a controllable center. Based on the bilinear form of this equation, 3-rogue wave solutions, 6-rogue wave solutions, and 9-rogue wave solutions are generated, respectively. The 3-rogue wave has a 'triangle-shaped' structure. The center of the 6-rogue wave forms a circle around a single rogue wave. The 9-rogue wave consists of seven first-order rogue waves and one second-order rogue waves as the center. Taking some appropriate parameters into account, their complex and interesting dynamics are shown in three-dimensional and contour plots. These new results are useful to understand the new features of nonlinear dynamics in real-world applications.

In this paper, we estimated half-lives using semi-empirical formulae for isotopes with Z = 100 − 126 in four α-decay chains, which can appear in the syntheses of the ^309−312126 nuclei. The spontaneous fission half-lives were calculated using the Anghel, Karpov, and Xu models, whereas the α-decay ones were predicted using the Viola-Seaborg, Royer, Akrawy, Brown, modified formulae of Royer, Ni, and Qian approaches. We found that there are large differences among the spontaneous fission half-lives estimated using the Xu model and those calculated using the others, which are up to 50 orders of magnitude. The α-decay half-lives also have large uncertainties due to difference in either methods or uncertainties in nuclear mass and spin-parities. Subsequently, there is an argument in determination of α-emitters, especially for the ³¹²126 isotope. On the other hand, the α-decay half-lives are in the range from a few microseconds (^309−312126) to thousands of years (^257−260Fm) in the decay chains. It was found that the half-lives are very sensitive to not only the shell closure but also the angular momentum in the α decay. For experiments, with relatively long half-lives (a few milliseconds), the ^289−292Lv isotopes can be observed as evidences for syntheses of the unknown super-heavy ^309−312126 nuclei. Furthermore, measurements for precise mass, fission barrier, and spin-parity are necessary to improve accuracy of half-life predictions for super-heavy nuclei.

Observables like neutron skin thickness and electric dipole polarizability in heavy nuclei are considered as most effective probes for the density dependence of nuclear symmetry energy at subsaturation density region. In the present work, within the framework of droplet model, we use finite range effective interactions to calculate the neutron skin thickness in ²⁰⁸Pb and the electric dipole polarizability in ⁶⁸Ni, ¹²⁰Sn and ²⁰⁸Pb. We correlate these quantities with the parameters of nuclear symmetry energy. Available experimental data on the neutron skin thickness in ²⁰⁸Pb and electric dipole polarizability in ⁶⁸Ni, ¹²⁰Sn and ²⁰⁸Pb are used to deduce information on the density slope parameter of nuclear symmetry energy at saturation and at subsaturation densities. Constraints such as 35.2 ≤ L(ρ₀) ≤ 64.4 MeV and 43 ≤ L(ρ_c) ≤ 55 MeV are obtained using experimental values for neutron skin thickness.

The measurement of electric dipole moment (EDM) in storage rings can potentially exceed the sensitivity of tests with neutral systems. The spin dynamics under such conditions is described by the Bargmann-Michel-Telegdi equation. It can be derived in the semiclassical approximation under several assumptions one of which is the zero pseudoscalar bilinear. However, many promising extensions to the standard model consider scalar-pseudoscalar couplings which assume nonzero electron pseudoscalar. We re-derive the spin precession equation under conditions that do not assume that pseudoscalar is zero. It leads to a correction term that might be required for matching the storage ring measurements with quantum field evaluations. Since the goal of storage ring experiments is to achieve unprecedently high accuracy in measuring EDM, it is important to accurately describe the spin dynamics under conditions of CP-violating extensions.

The differential cross sections of the forward coherent ω and ϕ mesons photoproduction from nuclei have been calculated using the Glauber model for the nuclear reaction. The measured cross section of the elementary reaction, i.e., γN → ω(ϕ)N reaction, are used as input in the Glauber model. The experimentally determined free-space scattering parameters of these mesons have been used to evaluate the meson nucleus interactions. The sensitivity of the cross section to the Fermi-motion and short-range correlation of the nucleon in the nucleus are studied. The calculated results are compared with the measured cross sections.

Multinucleon transfer reactions in ⁹⁰Zr+²⁰⁸Pb have been studied via fragment-γ coincidences, employing the PRISMA magnetic spectrometer coupled to the CLARA γ-array. An analysis on Y isotopes has been carried out incorporating spectroscopic as well as reaction mechanism aspects. New γ transitions have been observed in ⁹⁴Y, confirming the findings of recent studies where nuclei were produced via fission of uranium, and a comparison with near-by ^90,92Y isotopes populated in the same reaction has been discussed. Experimental cross sections have been extracted and compared with the GRAZING calculations, showing a fair agreement along the neutron pick-up side. The results confirm how multinucleon transfer reactions are a suitable mechanism for the study of neutron-rich nuclei.

Femtosecond laser pulses are the tools of choice for inducing and tracking the temporal evolution of electronic excitation in molecular systems. To obtain this information, a proper theoretical modeling of the observables monitored in these experiments is essential. Herein, we present a coherent approach to simulate the time-dependent signals that result from femtosecond pump-probe experiments with ionization detection. Thus, the transient signals derived from femtosecond pump-probe experiments are analyzed in terms of the coherent evolution of the energy levels perturbed by the excitation pulse. The model system is treated as the sum of independent two-level subsystems that evolve adiabatically or are permanently excited, depending on the detuning from the central wavelength of the excitation laser. This approach will allow us to explain numerically and analytically the convergence between the coherent and incoherent (rate equations) treatments for complex multi-level systems. It will be also shown that the parameter that determines the validity of the incoherent treatment is the distribution of states outside and inside the laser bandwidth, rather than the density of states as it is commonly accepted.

Ultracold atoms with an artificial gauge field provide a powerful platform for studying physical problems in various fields. We investigate the ground state of ultracold atoms in a hexagonal ring lattice with a synthetic magnetic field. The system undergoes a quantum phase transition characterized by degenerate and nondegenerate ground states. The phase transition depends on the atomic interaction and magnetic flux. With the quantum phase transition, a very interesting quantum odd–even parity effect emerges. The parity effects depend on a repulsive or attractive atomic interaction regime.

In this paper, a blood hemoglobin sensor is designed and analyzed by using a defected one-dimensional photonic crystal (1DPhCs). A structure of a binary defected 1D-PC is proposed. The structure is optimized by considering the effect of the angle of incidence, the defect layer thickness, and the refractive index of the first layer. The average sensitivity of the optimized sensor (Si/SiO₂)^N/D_d/(Si/SiO₂)^N is about 1025 nm/RIU. We have used the transfer matrix method in our study by using the MATLAB code to achieve the present results.

New generation of solar cells based on the implementation of quantum dots in the intrinsic region has attracted much attention due to the fact to that it takes advantage of photons with energies lower than the band gap for achieving high solar conversion efficiency. However, there is still a need for optimizing many parameters related to the solar cells, such as the size of quantum dots and nature of semiconductor materials. The main objective of this study is to extend the current knowledge of the intermediate band solar cells. In particular, we analyze the effect of dot size on the photonic properties of CdSe/ZnS and InP/ZnS quantum dot solar cells by considering the Schrodinger equation within the effective mass approximation. It is demonstrated that quantum dot size is a critical parameter to be controlled for high efficiency CdSe/ZnS and InP/ZnS quantum dot solar cells. Our results show that open-circuit voltage weakly depends on dot size for both systems while short-circuit current density is increased with dot size increasing. As a result, maximum efficiency values of 31.73% and 32.90% are obtained for CdSe/ZnS and InP/ZnS, respectively under full concentrated light for a dot size of 2.3 nm, thereby demonstrating the potentiality of these proposed heterostructures.

In this work, we present a simple design to act as a temperature sensor based on the well-known one dimensional photonic crystal. The main idea of the proposed sensor is essentially depending on the inclusion a defect layer of graphene monolayers deposited on nematic liquid crystal through the photonic crystal. The transfers matrix method, Kubo-Formula, and fitting experimental data represent the core axes of our theoretical treatment. Here, our design is prepared to sense temperature based on the shift of the resonant peak with the temperature variation. The performance of such sensor is demonstrated by calculating the sensitivity, figure of merit, detection limit, sensor resolution and the quality factor. The effect of the thickness of the defect layer and the mode of polarization as well on the performance of our sensor is investigated. The numerical results show that our sensor could be of interest in many fields of application due to the high values of its sensitivity and quality factor. The proposed sensor could provide a sensitivity of 4 nm °C⁻¹ and quality factor up to 11000.

In the present work, the radiative condensation and gravitational instabilities of inhomogeneous self-gravitating partially ionized dusty plasma have been studied with dust polarization force, ionization and recombination. The basic equations are constructed using four fluid model. The full dynamics of charged dust grains, ions and neutral species are employed considering the electrons as inertialess which have finite thermal conductivity and radiative cooling. The general dispersion relation is derived and discussed for different dusty plasma situations. It is found that the instability conditions are greatly affected due to the polarization force and recombination. Specifically, it is pointed out that the polarization force enhances the growth rate of both the radiative and gravitational instability while the recombination frequency decreases it. Both the parameters have influencing role in short wavelength regime. The e-folding times are calculated for maximum growth rates of gravitational and radiative condensation instabilities. The present work is applicable for study of interstellar molecular clouds and therefore the corresponding free fall time of molecular clouds is also presented.

High-beta tokamak equilibria with flow comparable to the poloidal Alfvén velocity in the reduced magnetohydrodynamics (MHD) model with two-fluid and ion finite Larmor radius (FLR) effects are investigated. The reduced form of Grad-Shafranov equation for equilibrium with flow, two-fluid and FLR effects is analytically solved for simple profiles. The dependence of the Shafranov shift for the magnetic axis and the equilibrium limits on the poloidal beta and the poloidal Alfvén Mach number are modified by the two-fluid and FLR effects. In the presence of the diamagnetic drift due to the two-fluid effect, the equilibrium depends on the sign of the E × B drift velocity. The FLR effect suppresses the large modification due to the two-fluid effect. By constructing magnetic flux coordinates and a local equilibrium model from the analytic solution, the effects of the non-circular property of the magnetic flux surfaces in the poloidal cross-section on the components of the curvature vector is examined in detail. The analytic solution is also used for the benchmark of the numerical code. The numerical solutions with non-uniform pressure, density and temperature profiles show similar behavior to analytic solution.

The nonlinear evolution of Langmuir oscillations (LOs) is studied in a cold plasma including the ion motion and (weakly) relativistic mass variation of electrons. For the purposes, a simple perturbation technique is used to solve the governing one-dimensional fluid-Maxwell's equations. The solutions show that the Langmuir mode frequency acquires spatial dependencies due to the finite ion inertia and relativistic effects. As a result, excited LOs mix up in phase and break at arbitrarily low amplitudes. An approximate expression for the phase-mixing time of LOs is then obtained, thus improving some earlier results. Phase-mixing time is found to decrease with the increase of both the electron-to-ion mass ratio parameter and relativistic factor. A comparative analysis between these two effects is also carried out to clarify which effect contributes more to the phase-mixing time. It is revealed that phase-mixing is induced more quickly due to the ion motion than the relativistic effects.

The ion orbits considering the resonant magnetic perturbation (RMP) fields with plasma response are studied numerically using the full orbit code based on HL-2A tokamak parameters. The results show that RMP with plasma response can cause a more significant radial orbit expansion than the vacuum RMP field. Further study exhibits that the physical mechanism of the orbit expansion relates to the resonant field amplification (RFA) effect. The passing orbits expansion become quite large when ions pass through the region where the perturbed field is strongly amplified. Meanwhile, the trapped orbits expansion is determined by the average value of the perturbed field where corressponding orbit goes by. This indicates that the plasma response to RMP plays an important role in changing the characteristics of ion orbits, which can lead to a redistribution of fast ions and thus providing a possible mechanism for the degradation of plasma confinements in experiments.

This study characterizes spatially varying optical emissions in a compact dipole plasma device driven at steady-state by continuous mode microwaves. The study is motivated by visual observations, which indicate a distinct pattern of alternate bright and less bright regions (bearing structural resemblance to the two particle radiation belts found in the Earth's magnetosphere). The investigation is performed in two experimental systems of cylindrical and spherical geometries, and boundary effects in the optical emissivity are observed in the smaller cylindrical system. Two optical diagnostic techniques are employed, namely, a simplistic linear inversion method, and the standard Abel inversion method, to invert the measured intensities and determine the local (spatially varying) emissivities in the equatorial plane of the dipole plasma. The study involves the design and development of the two optical probes, specifically, a telescopic probe capable of motion along a radial line (for linear inversion), and a mechanical gear-operated probe capable of bidirectional motion to obtain chord integrated intensities (for Abel inversion). Finally, the transition specific photon emission rates are determined by the application of a modified corona model, and the emission rates are compared with the experimental results. The existence of two bright belts separated by a darker band in the dipole plasma is confirmed by both the experimental and modeling results.

Structural, mechanical, thermal and magnetic properties of Quaternary Heusler alloys (QHA) CrFeTiZ (Z = Al, Si, Ge, Ga) are determined by employing full potential - linearized augmented plane wave (FP-LAPW) method using density functional theory (DFT). Geometry optimization of all these QHAs is accomplished and Type 2 is found the most stable. Elastic parameters reveal the mechanical stability and ductile behavior of all considered alloys. The calculated Debye Temperature (θ_D) assured that these alloys can be appropriate for high temperature devices due to high thermal conductivity ($\kappa$) and melting temperature (T_melt). All these compounds are half metallic (HM) in nature as the band gap (E_g) is present in one spin orientation. The values of E_g for CrFeTiAl and CrFeTiGa are 0.68 eV and 0.86 eV respectively which are obtained by employing generalized gradient approximation (GGA) while Hubbard parameter (U) with GGA is used to calculate E_g of CrFeTiGe and CrFeTiSi and the E_g are 0.93 eV and 0.9 eV. The calculated magnetic moment (MM) of CrFeTiZ (Z = Al, Si, Ge, Ga) alloys agrees with Slater-Pauling rule (SPR). From the obtained results it is envisaged that these materials are suitable candidates for spintronic and high temperature devices.

In this paper, transversely isotropic elastic properties of carbon nanocones are studied using molecular dynamics simulation implemented in the large-scale atomic/molecular massively parallel simulator (LAMMPS). All atomic interactions are calculated based on the Adaptive Intermolecular Reactive Empirical Bond Order (AIREBO) potential energy functions. To determine the five independent elastic constants, four distinct loading conditions, i. e. uniaxial tensile, longitudinal torsion, in-plane biaxial stretching, and in-plane shear are imposed. The results reveal that Young's and axial shear moduli are dependent on the apex angle of carbon nanocones, while the effect of the length on them is negligible. Furthermore, the in-plane bulk modulus and in-plane shear constant of these structures increase as their apex angle increases.

Published experimental data on the variation of the Y sputtering yield with the S_e electronic stopping power are analyzed. Systematic results for amorphizable (SiO₂, SrCeO₃, SrTiO_3, CeO₂) and non- amorphizable (LiF, KBr) insulators and semiconducting TiO₂, ZnO, SiC, UO₂ are used. Thermal activation mechanism of electronic sputtering is assumed. The ion-induced temperature is estimated applying the Analytical Thermal Spike Model. A highly accurate description of the experimental Y-S_e data is given in the whole range of S_e without the application of individual materials parameters apart the U activation energy. The values of U for SiO₂ and UO₂, are considerably lower than the U_s sublimation energies. Sputtering proceeds without threshold of S_e.

A green synthesis method using Azadirachta Indica leaf extract has been used to synthesized ZnO nanostructures. TEM image confirmed the formation of nanoparticles of size in the range of ∼50–100 nm. The stochiometry was also confirmed from the EDX spectroscopy. The structural analysis of the synthesized material was performed using the x-ray diffraction (XRD) data. The ZnO nanocrystals exhibit wurtzite unit cell structure as revealed from the XRD pattern. The calculation of lattice parameters shows that the distortion in the structure is very small. The material is highly crystalline with crystallite size of 20.05 nm and microstrain of 5.926 × 10⁻⁴. In this context crystallinity index is also calculated. The growth of the crystal is anisotropic as observed from the intensity of the diffraction and was quantified through the parameter degree of orientation. The synthesized ZnO nanostructure has large specific surface area. Other crystal parameters like Zn–O bond length, u-parameter, crystal volume were also calculated form the XRD pattern and show the structural perfection of the grown nanocrystal with a good figure of merit. Raman-shift measurements showed the existence of various phonon vibrational modes of the ZnO lattice. The material being synthesized by green approach is non-toxic in nature and may have potential applications in nanomaterials based medicinal and therapeutic applications.

The proposed novel optical system of composites of polymethyl methacrylate (PMMA)/titanium oxide (TiO₂) nanoparticles were planned to be used as polymeric materials according to their standing full applied optical applications. The spin coating method, an easy and cost-effective technique, was utilized to uniformly deposit and prepare these TiO₂/PMMA thin films on glass substrates, wherein nature, the films' uniformity, and structures' crystallinity. The interactions between the TiO₂ nanoparticle and PMMA as a matrix were confirmed through atomic force microscopy (AFM) and x-ray diffraction (XRD). The linear optical characterization of the obtained thin films was characterized using a spectrophotometer at a wavelength ranging from 200 nm to 1000 nm. Linear refractive index and absorption coefficient, direct and indirect optical bandgaps, and nonlinear optical parameters for the as-prepared samples were calculated using Kramers-Kroning analysis. Moreover, the optical limiting was studied using He-Ne laser 632.8 nm and green diode laser with 532 nm wavelength. This TiO₂/PMMA, as a novel optical system, is a good optical system to be used for capable various future technical applications, such as optical filter, solar cells, electronic apparatus, and optoelectronics devices.

In the present work, we will exhibit a theoretical analysis and optimization of electrical and optical characteristics of a short-wave infrared p-i-n detector closely lattice matched to conventional (001) InP substrate by the use of quaternary dilute bismide alloy In_xGa_1−xAs_1−yBi_y/In_xGa_1−xAs quantum wells as an active layer. The content of about 6% of Bismuth has been responsible of red-shift of the 50% cut-off wavelength from 2.2 towards 2.8 μm at room temperature, resulting in a band gap reduction of nearly 305 meV caused by the bismuth incorporation. The temperature dependence of zero-bias resistance area product (R₀A) and bias dependent dynamic resistance of the designed structure have been investigated thoroughly to analyses the dark current contributions mechanisms that might limit the electrical performance of the considered structure. It was revealed that the R₀A product of the detector is limited by thermal diffusion currents when temperatures are elevated whereas the ohmic shunt resistance contribution limits it when temperatures are low. The modeled heterostructure, reveals a comforting dark current of 1.25 × 10⁻⁸ A at bias voltage of −10 mV at 300 K. The present work demonstrates that the p-i-n detector based on compressively strained In_xGa_1−xAs_1−yBi_y quantum well is a potential candidate for achieving a short-wave infrared detection.

GdTb-FeCo based quaternary system of various thicknesses (30, 50, 75, 150, and 300 nm) is explored in pursuit of tuneable perpendicular magnetic anisotropy (PMA). Spin reorientation and strong PMA is evident at higher film thickness. A variety of microscopic domains can be referred to as disorder in domains, have been observed. Gd-like and Tb-like contributing domains are observed in various films. A critical thickness is observed at 150 nm, where most of the Tb-sublattices are dominated over the Gd-sublattices. Magnetic parameters do not follow the trend at 150 nm, which could be attributed to a lesser extent of pinning sites impeded to domain wall motions. The experimental finding is complemented with 3D micromagnetic simulations.

In this communication, detailed studies of the structural, microstructural, dielectric, and electrical properties of polycrystalline materials, (Bi_0.5Ba_0.25Sr_0.25) (Ti_0.5Fe_0.5)O₃ and (Bi_0.5Ba_0.25Sr_0.25) (Ti_0.25Mn_0.25Fe_0.5)O₃, synthesized by using a high–temperature solid-state-reaction method, have been reported. X-ray structural and scanning electron micrograph studies exhibit phase pure tetragonal system and surface morphology (size and distribution of grains and grain boundaries) of the samples respectively. Analysis of the temperature and frequency dependence of dielectric and electrical (impedance, modulus, and conductivity) data reveals the ferroelectric relaxor behavior, relaxation mechanism, and semiconductor (negative temperature coefficient of resistance) properties of the bulk BFBST and Mn modified BFBST electro-ceramics. The relaxation time and activation energy (E_a) were calculated from the above data. The characteristics of Mn modified BFBST have been compared to that of it's parent (BFBST) compound. The different inherent conduction mechanisms, such as Ohmic, hopping, space charge limited (SCLC) have been analyzed. The bulk- and interface-limited conduction processes were evidently found in the materials by the Poole–Frenkel (PF) and Schottky (SEmen modified BFBST have been compared to that of its parent (BFBST) compound) emission fitting of the J ∼ E characteristic data. The leakage data of BFBST-Mn (Mn modified Mn) quantified the average energy gap (E_g) in the range of 0.83–0. 87 eV for different applied voltages and in a wide range of temperature (25 °C–300 °C). With the increase in voltage, E_g decreases. This work suggests that Mn-substitution (Mn⁴⁺) at B (Ti⁴⁺) site keeping the stoichiometry undisturbed enhances structural, dielectric response (higher dielectric constant) and reduce the leakage behavior especially at low temperature and high-frequency range.

In this study, a plasmonic meta-surface absorber by semi-etalon structure is introduced due to the importance of wideband absorbers in the visible region as solar absorber. For this purpose, soft nanolithography method was adopted to construct semi-etalon absorber based on poly-dimethyl-siloxane flexible membrane and gold grating structure onto its top and down side. In parallel, the structure was simulated by the aid of finite difference time domain method, and obtained good agreement between the measured and simulated results. The results indicated the etalon-based absorber achieved light absorption from 500 to 700 nm compared to one face gold grating which works in the wavelength range 500 to 600 nm with half of absorbed power. In addition, color production was evaluated via the proposed structure, and tunable colors were produced by changing the polarization and incidence angle. Thus, the proposed structure as a good wide-band absorber, and can be used for producing tunable colors under different polarization and incidence angles. The absorber can offer new insight in larger area solar absorber based on soft nano-lithography method because of the low cost and flexibility.

We propose a simple method for calculating the metal vapor conductivity at the critical point and near-critical isotherms This method is based on the hypothesis of an electron jellium's existence as an origin of the conduction band in metal vapor's gaseous phase. The hypothesis was suggested in our previous works, mentioned further in this article. Satisfactory agreement with the experimental data for alkali metals (Cs, Rb) allows us to conclude that, at the critical point and its vicinity, the atomic metal vapors should be considered as a gaseous metal, that is not a dielectric state of matter.

We have addressed the several unpublished elastic, mechanical, optical, anisotropic and magnetic properties of V₂NiSb inverse Heusler alloy through the density functional theory (DFT) framework. Calculated elastic constants indicate mechanical stability and ductile mechanical character of the alloy. The alloy has high elastic anisotropy. Some optical properties like dielectric function, absorption, reflectance, optical conductivity, etc were also surveyed. According to the obtained results, V₂NiSb is a good absorber and high refractive index material in the ultraviolet (UV) region. The magnetic results of the alloy signify typical ferromagnetism with 0.8 μ_B total magnetic moment and compares well former findings. Our results may further shed light on the possible experimental researches of V₂NiSb alloys for practical applications.