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In this article we present a review on recent experimental works toward the formation of visible light responsive composite photocatalysts on the basis of titania nanoparticles and carbon nanomaterials of different types. The research results achieved in last years has shown that the nanocomposite photocatalysts comprising titania nanoparticles and graphene or graphene oxide sheets, and also nanoparticles of noble metals and metallic oxides, exhibited the evident priority compared to the others. Therefore our review emphasizes the research on these promising visible light responsive nanophotocatalysts.

Zinc oxide has emerged as a material of great interest due to its unique optical, electrical and magnetic properties. This review comprehensively covers the various aspects of zinc oxide tetrapods. Tetrapod is a one dimensional zinc oxide nano-microstructure and has been found to have very promising applications in diverse fields. The growth model, properties, synthesis methods and variations in the tetrapod morphology by varying the synthesis conditions have been discussed. The promising applications of zinc oxide tetrapod morphology have been also discussed in detail.

In this study a novel magnetic composite used as a photocatalyst with combination of zinc oxide nanoparticles and chitosan (ZnO/Fe₃O₄/CS) was synthesized by a simple co-precipitation method. The role of the prepared magnetic nanocomposite is to improve the removal efficiency of textile dye due to the photocatalytic activity of zinc oxide nanoparticles and reusable capacity of Fe₃O₄ magnetic nanoparticles. Constituents and structure properties of ZnO/Fe₃O₄/CS were investigated by scanning electron microscopy (SEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Magnetic property of the prepared composite was determined by vibrating sample magnetometer (VSM). The results demonstrated that ZnO/Fe₃O₄/CS nanocomposite dramatically improved the removal efficiency of reactive blue 198 dye (RB198) with high photocatalytic activity and easy separation by a permanent magnet. In addition, the photocatalytic activity of the prepared composite was also performed under different parameters such as contact time, initial pH, the amount of composite and initial concentration of RB198. Interestingly, ZnO/Fe₃O₄/CS nanocomposite still showed high removal efficiency after recycling three times and performed in a real textile dyeing wastewater.

The antimicrobial and anticancer efficiencies of green synthesized silver nanoparticles (AgNPs) through biogenic extracts were assessed on three bacterial strains and two cancer cell lines. Bio-synthesized AgNPs were achieved through domestic microwave generator for obtaining extracts from Asian nuts and Egyptian blackberry fruits. Surface plasmon resonance (SPR) ∼435 nm demonstrated AgNPs earlier formation by the fruit extract. Capping by triglycerides/almond and phenols/berry extracts were responsible for the reduction proved by FTIR. XRD calculated particle sizes were 18 and 42 nm while TEM sizes are 24.5 and 21.5 nm for AgNPs from almond nut and blackberry fruits extracts (Alm.N.Ext. and BB.F.Ext.), respectively. Ag 3d5/2 was recorded at 368.12 eV for both samples through XPS. The monodispersed AgNPs recorded 0.727 and 0.5 polydispersity indices (PdI) for almond/Ag and berry/Ag, respectively. Zeta potential ∼ −31 and −13.2 for the same sequence confirmed the higher stability of the former. Reaction kinetics confirmed the advantage of fruit extract consuming only six minutes compared to nuts, consuming twice. Bactericidal effect of the extracts seldomly presented remarkable inhibition compared to extracts/Ag against the three species. In addition, Alm.N.Ext. showed the highest inhibition against staphylococcus aureus (S. aureus) at 4 mM. The anti-cancerous effect of Ag/berry against HepG2 is stronger than Ag/almond, and similarly for MCF7.

This work is devoted to the construction of the quantum field theory of the interacting system of plasmons, photons and phonons on the basis of general fundamental principles of electrodynamics and quantum field theory of many-body systems. Since a plasmon is a quasiparticle appearing as a resonance in the collective oscillation of the interacting electron gas in solids, the starting point is the total action functional of the interacting system comprising electron gas, electromagnetic field and phonon fields. By means of the powerful functional integral technique, this original total action is transformed into that of the system of the quantum fields describing plasmons, transverse photons, acoustic as well as optic longitudinal and transverse phonons. The collective oscillations of the electron gas is characterized by a real scalar field φ(x) called the collective oscillation field. This field is split into the static background field φ₀(x) and the fluctuation field ζ(x). The longitudinal phonon fields ${{{\bf Q}}^{al}}(x),$${{{\bf Q}}^{ol}}(x)$ are also split into the background fields ${\bf Q}_{0}^{al}(x),$${\bf Q}_{0}^{ol}(x)$ and dynamical fields ${{{\bf q}}^{al}}(x),$${{{\bf q}}^{ol}}(x)$ while the transverse phonon fields ${{{\bf Q}}^{at}}(x),$${{{\bf Q}}^{ot}}(x)$ themselves are dynamical fields ${{{\bf q}}^{at}}(x),$${{{\bf q}}^{ot}}(x)$ without background fields. After the canonical quantization procedure, the background fields φ₀(x), ${\bf Q}_{0}^{al}(x),$${\bf Q}_{0}^{ol}(x)$ remain the classical fields, while the fluctuation fields ζ(x) and dynamical phonon fields ${{{\bf q}}^{al}}(x),$${{{\bf q}}^{at}}(x),$${{{\bf q}}^{ol}}(x),$${{{\bf q}}^{ot}}(x)$ become quantum fields. In quantum theory, a plasmon is the quantum of Hermitian scalar field σ(x) called the plasmon field, longitudinal phonons as complex spinless quasiparticles are the quanta of the effective longitudinal phonon Hermitian scalar fields ${{\theta }^{a}}(x),$${{\theta }^{0}}(x),$ while transverse phonons are the quanta of the original Hermitian transverse phonon vector fields ${{{\bf q}}^{at}}(x),$${{{\bf q}}^{ot}}(x).$ By means of the functional integral technique the original action functional of the interacting system comprising electron gas, electromagnetic field and phonon fields is transformed into the total action functional of the resultant system comprising plasmon scalar quantum field σ(x), longitudinal phonon effective scalar quantum fields ${{\theta }^{a}}(x),$${{\theta }^{0}}(x)$ and transverse phonon vector quantum fields ${{{\bf q}}^{at}}(x),$${{{\bf q}}^{ot}}(x)$.

A new scheme of grafting poly (ethylene glycol) onto chitosan was proposed in this study to give new material for delivery of insulin over oral pathway. First, methoxy poly(ethylene glycol) amine (mPEGa MW 2000) were grafted onto chitosan (CS) through multiples steps to synthesize the grafting copolymer PEG-g-CS. After each synthesis step, chitosan and its derivatives were characterized by FTIR, ¹H NMR Then, insulin loaded PEG-g-CS nanoparticles were prepared by cross-linking of CS with sodium tripolyphosphate (TPP). Same insulin loaded nanoparticles using unmodified chitosan were also prepared in order to compare with the modified ones. Results showed better protecting capacity of the synthesized copolymer over original CS. CS nanoparticles (10 nm of size) were gel like and high sensible to temperature as well as acidic environment while PEG-g-CS nanoparticles (200 nm of size) were rigid and more thermo and pH stable.

A 2D analytical tunnel field-effect transistor (FET) potential model with cylindrical gate (CG-TFET) based on the solution of Laplace's equation is proposed. The band-to-band tunneling (BTBT) current is derived by the help of lateral electric field and the shortest tunneling distance. However, the analysis is extended to obtain the subthreshold swing (SS) and transfer characteristics of the device. The dependency of drain current, SS and transconductance on gate voltage and shortest tunneling distance is discussed. Also, the effect of scaling the gate oxide thickness and the cylindrical body diameter on the electrical parameters of the device is analyzed.

One-dimensional self-assembled single-crystalline hexagonal tungsten trioxide (WO₃) nanostructures were synthesized by wet chemical-assisted hydrothermal processing at 120 °C for 24 h using sodium tungstate and hydrochloric acid. Urchin-like hierarchical nanorods (petal size: ∼16 nm diameter and 110 nm length) were obtained. The samples were characterized by field emission scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy and x-ray diffraction. Sensors based on WO₃ nanorods were fabricated by coating them on SiO₂/Si substrate attached with Pt interdigitated electrodes. NH₃ gas-sensing properties of WO₃ nanorods were measured at different temperatures ranging from 50 °C to 350 °C and the response was evaluated as a function of ammonia gas concentration. The gas-sensing results reveal that WO₃ nanorods sensor exhibits high sensitivity and selectivity to NH₃ at low operating temperature (50 °C). The maximum response reached at 50 °C was 192 for 250 ppm NH₃, with response and recovery times of 10 min and 2 min, respectively.

Electroplating is an important step in microfabrication in order to increase thickness of undersized parts up to a few micrometers with a low-cost, fast method that is easy to carry out, especially for metals such as copper, nickel, and silver. This important step promotes the development of the fabrication technology of electronic devices on a flexible substrate, also known as flexible electronic devices. Nevertheless, this technology has some disadvantages such as low surface uniformity and high resistivity. In this paper, parameters of copper electroplating were studied, such as the ratio of copper (II) sulfate (CuSO₄) concentration to sulfuric acid (H₂SO₄) concentration and electroplating current density, in order to obtain low resistivity and high surface uniformity of the copper layer. Samples were characterized by scanning electron microscopy (SEM), four-point probe, and surface profiler. The results showed that the sample resistivity could be controlled from about 2.0 to about 3.5 μΩ · cm, and the lowest obtained resistivity was 1.899 μΩ · cm. In addition, surface uniformity of the electroplated copper layer was also acceptable. The thickness of the copper layer was about 10 μm with an error of about 0.5 μm. The most suitable conditions for the electroplating process were CuSO₄ concentration of 0.4 mol l⁻¹, H₂SO₄ concentration of 1.0 mol l⁻¹, and low electroplating current density of 10–20 mA cm⁻². All experiments were performed on a flexible polyethylene terephthalate (PET) substrate.

The exploitation of marine seaweed (Sargassum wightii) extract as a low-cost sensitizer for a ZnO photoanode based solar cell is reported. The UV–vis absorbance spectrum of the Sargassum wightii (S. wightii) extract has exhibited three absorption peaks at 412.5, 610 and 659.5 nm in visible region of the solar spectrum. The pigment analysis has confirmed the presence of photosynthetic pigments such as chlorophylls, carotenoids and fucoxanthin. The photovoltaic performance of the S. wightii extract as a sensitizer in ZnO photoanode based solar cell is examined under simulated solar light irradiation. The solar cell sensitized with the S. wightii extract has delivered a short-circuit photocurrent density (J_sc) of 203 μA cm⁻², open-circuit photo-voltage (V_oc) of 0.33 V, maximum peak power (P_max) of 31.02 μW, fill factor of 0.46 and an overall solar to electrical energy conversion efficiency (η) of 0.07%. The sustainability of the solar cell is demonstrated through stability study. The overall results of this study suggest that the exploration of vast marine seaweed pigment resources and their use as sensitizer in solar cell would be a low-cost and environment friendly alternative to the expensive ruthenium metal complexes.

The authors report the synthesis of Fe₃O₄ nanoparticles by wet chemical reduction technique at ambient temperature and its characterization. Ferric chloride hexa-hydrate (FeCl₃ · 6H₂O) and sodium boro-hydrate (NaBH₄) were used for synthesis of Fe₃O₄ nanoparticles at ambient temperature. The elemental composition of the synthesized Fe₃O₄ nanoparticles was determined by energy dispersive analysis of x-rays technique. The x-ray diffraction (XRD) technique was used for structural characterization of the nanoparticles. The crystallite size of the nanoparticles was determined using XRD data employing Scherrer's formula and Hall–Williamson's plot. Surface morphology of as-synthesized Fe₃O₄ nanoparticles was studied by scanning electron microscopy. High resolution transmission electron microscopy analysis of the as-synthesized Fe₃O₄ nanoparticles showed narrow range of particles size distribution. The optical absorption of the synthesized Fe₃O₄ nanoparticles was studied by UV–vis–NIR spectroscopy. The as-synthesized nanoparticles were analyzed by Fourier transform infrared spectroscopy technique for absorption band study in the infrared region. The magnetic properties of the as-synthesized Fe₃O₄ nanoparticles were evaluated by vibrating sample magnetometer technique. The thermal stability of the as-synthesized Fe₃O₄ nanoparticles was studied by thermogravimetric technique. The obtained results are elaborated and discussed in details in this paper.

In this work the sensitivity of process parameters like channel length (L), channel thickness (t_Si), and gate work function (φ_M) on various performance metrics of an undoped cylindrical gate all around (GAA) metal-oxide-semiconductor field effect transistor (MOSFET) are systematically analyzed. Undoped GAA MOSFET is a radical invention as it introduces a new direction for transistor scaling. In conventional MOSFET, generally the channel doping concentration is very high to provide high on-state current, but in contrary it causes random dopant fluctuation and threshold voltage variation. So, the undoped nature of GAA MOSFET solves the above complications. Hence, we have analyzed the electrical characteristics as well as the analog/RF performances of undoped GAA MOSFET through Sentaurus device simulator.

Grand canonical Monte Carlo (GCMC) simulation combined with the ideal adsorbed solution theory (IAST) and a statistical method were utilized to investigate the effect of functional groups on zirconium oxide based metal-organic frameworks (MOFs) Zr₆-AzoBDC (Zr₆A) for the gases (H₂, CH₄) adsorption property and CO₂/CH₄ selectivity under low pressure. The results showed that phenyl groups containing nitrogen (pyridine, pyrimidine) and thiophene group enhance the gas affinity with MOFs, therefore increasing both gravimetric and volumetric uptake. In addition, this behavior can also cause significantly improved selective capture of CO₂ from CO₂/CH₄ gas mixtures. Among functional groups studied, the sulfonic acid group can potentially improve CH₄, CO₂ uptake and H₂ isosteric heat of adsorption. These findings would play a vital role in designing new materials toward gas adsorption properties.

In this report we present the initial results of the use of different silver nanostructures deposited on silicon for trace detection of paraquat (a commonly used herbicide) using the surface-enhanced Raman scattering (SERS) effect. More specifically, the SERS-active substrates were fabricated from silver nanoparticles (AgNPs) deposited onto the flat surface of a silicon wafer (AgNPs@Si substrate), as well as on the surface of an obliquely aligned silicon nanowire (SiNW) array (AgNPs@SiNWs substrate), and from silver nanodendrites (AgNDs) deposited onto the flat surface of a silicon wafer (AgNDs@Si substrate). Results showed that with the change of the structure of the SERS-active substrate, higher levels of SERS enhancement have been achieved. Specifically, with the fabricated AgNDs@Si substrate, paraquat concentration as low as 1 ppm can be detected.

We report on the photoluminescent properties of Ba_0.9Eu_0.1MgAl₁₀O₁₇ (BAM) phosphors in correlation with the host crystalline structures. The phosphors were synthesized by citrate sol-gel process, followed by a sintering and a reduction step, both at elevated temperatures. We found that the phosphors were amorphous when sintered at temperatures below 900 °C. At 1000 °C, the crystalline structure was mainly that of BaAl₂O₄ phase. The BaMgAl₁₀O₁₇ phase appeared at 1100 °C, and became dominant with increasing temperature. At 1300 °C, the BaAl₂O₄ phase almost disappeared, and only BaMgAl₁₀O₁₇ features were found. The luminescent characteristics of the phosphors were closely related to the structures of the host lattice. Under the same reduction conditions, the phosphors sintered at 1000 °C showed the emission of both Eu³⁺ and Eu²⁺. For the phosphors sintered at higher temperatures, the main features were originated from the emission of Eu²⁺. We additionally observed the increase of emission intensity and the broadening of emission spectra with increasing reduction temperature.

A series of Pd/HZSM-5 catalysts modified by various metallic species, including Co, Ni, Fe, Re, and Cu, was prepared by sequential impregnation. Contents of Pd and second metals in modified catalysts were 0.8 and 1.0 wt%, respectively. Physico-chemical characteristics of catalysts were investigated by nitrogen physi-sorption (BET), x-ray diffraction (XRD), transmission electron microscopy (TEM), ammonia temperature programmed desorption (NH₃-TPD), temperature programmed reduction (TPR) and hydrogen pulse chemisorption (HPC). Coke formation was studied by the method of thermogravimetric analysis (TGA). The activities of catalysts in n-hexane isomerization were studied in a micro-flow reactor under atmospheric pressure at 250 °C, and molar ratio of H₂: n-hexane of 5.92. It was found that Co, Ni, Fe, and Re additives exhibited geometric and electronic effects toward Pd/HZSM-5 catalyst, leading to an enhancement of its activity and stability. On the contrary, Cu additive caused Pd/HZSM-5 to become poorer in activity and stability.

Gold nanoparticles (AuNPs) of 15–20 nm size range have attracted attention for producing smart sensing devices as diagnostic tools in biomedical sciences. Citrate capped AuNPs are negatively charged, which can be exploited for electrostatic interactions with some positively charged biomolecules like antibodies. In this paper we describe a method for the low cost synthesis of gold nanoparticles using sodium citrate (Na₃Ct) reduction in chloroauric acid (HAuCl₄.3H₂O) by microwave heating (diameter about 13–15 nm). Gold nanoparticles were functionalized with surface activation by 3-mercaptopropionic acid for attaching antibody. These nanoparticles were then reacted with anti-E. coli O157:H7, using N-hydroxy succinimide (NHS) and carbondimide hydrochloride (EDC) coupling chemistry. The product was characterized with UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy and zeta potential. In addition, the binding of antibody-gold nanoparticles conjugates to E. coli O157:H7 was demonstrated using transmission electron microscopy (TEM).

On the basis of general principles of electrodynamics and quantum theory we have elaborated the quantum field theory of plasmons in the plane metallic slab with a finite thickness by applying the functional integral technique. A hermitian scalar field φ was used to describe the collective oscillations of the interacting electron gas in the slab and the effective action functional of the system was established in the harmonic approximation. The fluctuations of this scalar field φ around the background one φ₀ corresponding to the extreme value of the effective action functional are described by the fluctuation field ζ generating the plasmons. The dynamical equation for this fluctuation field was derived. The solution of the dynamical equation would determine the plasmon energy spectrum.

Using biogenic nanoscale metals (Fe, Cu, ZnO, Se) to supplement into diet premix of reproductive LV (a Vietnamese Luong Phuong chicken breed) chickens resulted in certain improvement of poultry farming. The experimental data obtained showed that the farming indices depend mainly on the quantity of nanocrystalline metals which replaced the inorganic mineral component in the feed premix. All four experimental groups with different quantities of the replacement nano component grew and developed normally with livability reaching 91 to 94%, hen's bodyweight at 38 weeks of age and egg weight ranged from 2.53–2.60 kg/hen and 50.86–51.55 g/egg, respectively. All these farming indices together with laying rate, egg productivity and chick hatchability peaked at group 5 with 25% of nanoscale metals compared to the standard inorganic mineral supplement, while feed consumption was lowest. The results also confirmed that nanocrystalline metals Fe, Cu, ZnO and Se supplemented to chicken feed were able to decrease inorganic minerals in the diet premixes at least four times, allowing animals to more effectively absorb feed minerals, consequently decreasing environmental pollution risks.

Nano Co₃O₄ has been fabricated by co-precipitation of 0.1 M cobalt chloride with 0.1 M oxalic acid. During precipitation, high-frequency signal (9 V) was applied to the precipitation bath. Three samples were prepared at three different frequencies (0 Hz, 400 KHz, 1 MHz). The samples were dried at 120 °C for 20 h, and then calcined at 700 °C for 5 h to obtain the nano Co₃O₄. The prepared samples were investigated via XRD and TEM studies. According to the present data the particle size decreases from about 164 to 80 nm and the width of the particle size distribution decreases to half of its value with increasing frequency from 0 Hz to 1 MHz.