In this work, we present experimental evidence and analytical studies of the XRD patterns and optical characterizations of ZnS films with different optical thicknesses. Thin films of ZnS were deposited on glass substrates by thermal evaporation. The crystallite size increased as the optical thicknesses. The overall absorbance has been increased with the film thickness and the direct band gap was obtained. It decreases with the increasing in the thickness of the films.

In the present paper, we report the compensation effect for the crystallization of different binary and ternary systems of some chalcogenide glasses. We have observed Meyer-Neldel rule between the pre-exponential factor K 0 of rate constant K(T) of crystallization and activation energy of crystallization E c in the present case.

The aim of this work is to model the interaction of L-band electromagnetic waves with coastal breaking sea waves. The breaking sea waves’ profiles are generated using the desingularized technique and the electromagnetic waves scattering is computed using the high-order method of moments (HO-MoM) combined with non uniform rational basis spline (NURBS) geometry. Our study mainly focuses upon the electromagnetic waves behavior in the crest and the cavity of breaking sea waves.

The reverse I-V characteristics of In-pWSe2 and Al-pWSe2 Schottky barrier diodes were investigated at room temperature with two different metal thicknesses. A model is presented on the basis of thermionic emission and tunneling to explain the unusually high leakage current observed in these diodes. It has been identified that the major contribution to leakage current is by tunneling mechanism, which significantly affects the reverse I-V characteristics of the Schottky contacts, along with a very small amount of thermionic emission current. We have also extracted various Schottky diode parameters of the two types of diodes fabricated and compared the data. It is found that the diode with 1000 Å metal thickness possesses more tunneling current compared to 500 Å diode.

This article presents a time domain discontinuous Galerkin method applied for solving the con-servative form of Maxwells’ equations and computing the radiated fields in electromagnetic compatibility problems. The results obtained in homogeneous media for the transverse magnetic waves are validated in two cases. We compare our solution to an analytical solution of Maxwells’ equations based on characteristic method. Our results on shielding effectiveness of a conducting wall are same as those obtained from analytical expression in frequency domain. The propagation in heterogeneous medium is explored. The shielding effectiveness of a composite wall partially filled by circular conductives inclusions is computed. The proposed results are in conformity with the classical predictive homogenization rules.

A double-layered membrane model is proposed to explain raft formation and induction on extracellular (outer) and cytoplasmic (inner) leaflets of plasma membranes in a situation where only the outer layer has a tendency to phase-separate. In the model, lipid exchange with the surrounding medium is allowed on both layers, but lipid exchange between layers is not allowed. Simulations display domain stabilization on both layers. The effect of the lipid recycling frequencies on stationary domain sizes is also investigated. It is found that stationary domain sizes decrease when lipid recycling frequencies are stronger. Linear stability analysis is used to verify the results.

Ozone was generated using dielectric barrier discharges at atmospheric pressure to treat sugarcane bagasse for bioethanol production. It was shown that interaction of ozone molecules with the pretreatment reactor wall (stainless steel) needs to be considered during bagasse oxidation in order to evaluate the pretreatment efficiency. The decomposition coefficients for ozone on both materials were determined to be (3.3 ± 0.2) × 10−8 for stainless steel and (2.0 ± 0.3) × 10−7 for bagasse. The results have indicated that ozone decomposition has occurred more efficiently on the biomass material.

Tilt growth is usually observed for the thin film growth on a substrate. Such tilt growth is considered as a consequence of the relaxation of the misfit strain between the epilayer and the substrate. In this paper, we propose a theoretical method to obtain the tilt angle of the epilayer, especially suitable for the heterostructure with large misfit strain which can be more than 10%. As an application of our method, we focus on two growth cases. One case is the growth of MnAs epilayer on GaAs (113) substrate with the lattice mismatch between the MnAs epilayer and the GaAs (113) substrate as high as 80%. And the other case is the growth of GaN epilayers on GaAs $\{1 \overline 1 l\}$ substrates. Results calculated from our method for the two cases agree well with the experimental observations. This method is general, and can be applied to other material systems with large lattice mismatch.

It has been systematically investigated about the magnetic properties of the composite and single-phase SrFe12O19 prepared with the precursor of different Fe3+/Sr2+ molar ratios of 12:1, 11:1 and 10:1, respectively. With increasing the calcinations temperature, the coercivity of all samples decreases which can be determined by the stress model. The δm(H) results indicate that the intergrain exchangecoupling interaction exists both in composite and in single-phase SrFe12O19, resulting in the remanence magnetization enhancement, and the magnetostatic interaction become dominant in the samples with higher calcinations temperatures. The irreversible susceptibilities χirr(H) curves show that there may exhibit the exchange-spring behavior in the composite SrFe12O19 with more soft magnetic γ-Fe2O3, and the irreversible switching field may be qualitatively used to determine the coercivity magnitude.

Planar metal/semiconductor/metal (PMSM) junctions buried in a SiO2 layer are fabricated using electron beam lithography on a silicon sample. A technique of jump of pixels is used to obtain different sizes of junctions, the smallest having an inter-electrode distance of 5 nm. The current-voltage characteristics and the variation of the junction conductance with the temperature down to 8 K have been studied. At all sizes and for both polarities, the I−V curves correspond to the reverse characteristic of a metal/semiconductor contact. At low bias voltage, the influence of a thin insulator interfacial layer between the metal and the semiconductor has been pointed out. For these junctions, a non-linear low voltage I−V characteristics is observed before the large voltage thermionic emission regime. For the smallest junctions obtained without interfacial oxide layer, a linear I−V characteristic is recovered at low voltage. Their conductance can be lowered by decreasing the temperature.

Thin films of titanium, copper and silver with various roughnesses were prepared by physical vapour deposition technique: dc magnetron sputtering. By varying the deposition time from few minutes to one hour it was possible to obtain metallic films with surface roughness average ranging from 1 to 20 nm. The wettability of these films was studied by measuring the contact angle using the sessile drop method and surface forces were investigated using the atomic force microscopy (AFM) by measuring the pull-off force between the AFM tip and the surfaces. Experimental results have been mainly discussed in terms of metal surface reactivity, Young modulus of the materials and real surface of contact between the AFM tip and the film surfaces.

This paper presents a non-linear model of the induction machine which takes in consideration the influence of the saturation on its behaviour. The approach, based on the Park's two-phase model, is established using a finite-element flux calculation program. This program allows to validate hypothesis formulated in order to simplify flux-current relationships. A comparison between the dynamic response of the model and the response obtained by a general model based on the coupled electro-magnetic equations permits to validate it.

We investigated the electrical properties of polyaniline-coated magnetic nanoparticles as a signal transducer for application in a disposable membrane strip biosensor. The size of these particles (~100 nm) was investigated by a transmission electron microscope. Electrical properties of these nanoparticles were investigated by four-point probe measurements and I-V measurements. Polyaniline-coated magnetic nanoparticles had a resistivity of 0.385 Ω cm and showed ohmic behavior. Resistance decreased with increasing concentration of polyaniline. We also demonstrated that the resistance decreased with increasing concentration of biotinylated IgG conjugated with these nanoparticles.

P-Aminoazobenzene (PAAB) is one of the 24 kinds of carcinogenic azo dyes that the European Union forbids but it does not yet have an official method to detect PAAB. This paper experimentally observes the Normal Raman Spectrum (NRS) and infrared absorption spectrum of PAAB and presents theoretical vibrational spectra calculated from a density functional theory (DFT) method on the basis of B3LYP with 6–31 basis set. The calculated results show very good agreement with the experimentally observed IR and Raman frequencies. We also report the SERS spectra of PAAB adsorbed on silver and copper layers, which offer a sensitive but simple method to detect PAAB. Finally, the possible adsorbed states of PAAB on the silver and copper layers are discussed.

The study concerns remote controlled sensors, associating micro-mechanical and microwave data communication functions. A radio link can be used to transmit information from the sensor as well as to provide internal power supply. Applications include Wireless Sensor Networks projects. An important operation is performed through a passive microwave frequency shifter used for retransmission. Two structures of this frequency shifter using silicon membrane micro-mechanical capacitors are described, with further details concerning the optimisation of the dimensions using electro-mechanical modellisation, the problems in technological silicon implantation, and some first experimental results.

Single crystals of MoSe2−xTex (x = 0.25, 0.5, 1, 1.5, 1.75) were grown by chemical vapor transport technique. The stoichiometric composition of grown crystals was confirmed by energy dispersive X-ray spectroscopy. Transport properties like electrical resistivity, Seebeck co-efficient measurements at high temperature and Hall effect at room temperature were studied on these samples. The obtained results are discussed in details in this paper.

The effect of (0.5–3.5) wt.% Ag additions on microstructure, melting, corrosion and mechanical properties of Sn-9Zn eutectic lead-free solder alloy has been studied and analyzed. The study included X-ray diffraction and scanning electron microscopy (SEM) to identify the microstructure of these alloys. The results showed that, continuous additions of Ag caused formation of Ag-Zn and Ag-Sn compounds which led to decrease the precipitations of Zn in Sn-matrix. These compounds led to increase the melting point of the alloys, which confirmed by the formation of small endothermic peaks in the higher temperature range followed the main peak of the DTA curves. Also, the DTA measurements confirmed that the alloy of composition Sn-9Zn-3.5Ag is the ternary eutectic alloy. Vicker's micro-hardness number of Sn-9Zn alloy increases with small additions of 0.5 and 1 wt.% Ag. Furthermore, it decreases to lower values with further increase of Ag content. Also, micro-creep behaviour, creep rate and corrosion behaviour of the Sn-9Zn-Ag alloys have been measured at room temperature.

In previously published papers [G. Musa et al., Rom. Rep. Phys. 49, 195 (1997); G. Musa et al., Eur. Phys. J. Appl. Phys. 4, 165 (1998)] we reported a drastic change of time evolution of the barrier discharge current at the addition of hydrogen to neon–filling gas of the discharge device. Both, discharge current and discharge emitted light durations increase at least five times. We established that the main explanation of the above mentioned behavior consists in the negative-positive ion recombination, process which has one of the largest known cross–section [M.A. Lieberman and A.J. Lichtenberg, Principles of plasma discharges and material processing (John Wiley & Sons, N.Y., 1994)]. The first condition to have negative-positive ions recombination is to use as filling gas of the discharge device an electronegative–electropositive gas mixture [G. Musa et al., ESCAMPIG-16, Grenoble France, 2002, Vol. 2, p. 29; G. Musa et al., J. Phys. D: Appl. Phys. 18, 2119 (1985); A. Baltog et al., Contrib. Plasma Phys. 40, 537 (2000); G. Musa and A. Baltog, Contrib. Plasma Phys. 43, 210 (2003)]. Additional conditions must be fulfilled in order to ensure enough density of negative ions necessary for such a recombination process. An increased “consumption” of electrons is necessary to produce needed negative ions. Consequently, the wall polarization process is slowing down with subsequent increase of the light emission and discharge current duration. Possible use of this increase of light emission at electronegative gas addition to the filling gas neon as a mean to increase the discharge light generation efficiency is considered.

GaN films were grown using metal-organic chemical vapor deposition (MOCVD) on intentionally roughened c-sapphire in order to study the effect of the substrate roughness. Controlled substrate damage was achieved by exposing the substrate surfaces to controlled amounts of trimethylgallium followed by exposure to hydrogen at elevated temperature. The bulk film quality was studied by high-resolution X-ray diffraction and the surface topography was examined by atomic force microscopy. It was observed that mild substrate roughness (surface pit depth up to 30 nm) does not have a significant effect on the bulk film quality nor the GaN surface topography, and that recovery of the surface roughness is observed in very early stages of film growth. Cross sectional transmission electron microscopy confirmed that MOCVD GaN grown on inclined sidewalls etched in c-sapphire maintained the $\{0001\}_{\rm sapphire}\parallel\{0001\}_{\rm GaN}$ epitaxial relationship despite the substrate miscut of ca. 15° with respect to the c-axis.

The photoelectrocatalytic activity of Zn-loaded reduced graphene oxide-titania (RGO-TiO2) composite coatings on mild steel substrate was investigated in detail. Zn-loaded RGO-TiO2 composite films were prepared by using DC electrochemical co-deposition technique onto mild steel substrate in an acid-sulphate bath electrolyte. The cyclic voltammetry and photocurrent response studies showed that the Zn-loaded RGO-TiO2 films have improved photoelectrocatalytic performance. The embedding of metallic Zn into the RGO-TiO2 promoted an effective charge carriers separation by minimizing the recombination losses. In this manner, metallic Zn will act as efficient photo-induced electron acceptors from the bulk of RGO-TiO2 film. Thus, the transportation of the electrons from the working electrode to the counter electrode was improved significantly.