Growth of the ternary semiconductor Znx Cd $_{1-x}$ S in MOR type zeolite matrices is reported. Hydrothermal synthesis was used for growing such semiconductor compound and analogues by using Cd and Zn salts as well as Thiourea as precursor sources of Cd, Zn and S elements, respectively. Following synthesis routes previously reported, bulk CdS with a band gap of 2.26 eV was obtained to be used as a reference. The final products were mainly characterized by Raman and Photoluminescence spectroscopies. The study shows the formation of Zn diluted ZnCdS ternary alloy in the final products of the synthesis, particularly for those samples with a Zn(wt%)/Cd(wt%) ratio higher than 0.05, and also the formation of a ZnO phase with a band gap value around 3.3 eV for the sample with the highest Zn content.

A comprehensive analysis on the amorphous to crystalline phase transformation in Pb:GeSbTe chalcogenide alloy has been discussed. The structure identified with X-ray measurements has been discussed in relation to thermal analysis carried out on bulk samples. Optical constants have been calculated in the 350 to 800 nm wavelength range, using Fresnel's equation. The effect of Pb substitution on the optical contrast in terms of change in reflectivity and optical parameters (viz. refractive index, extinction coefficient) has been discussed. Marginal decrease in the optical contrast has been observed with a small increase in Pb content, which is effective to maintain the sufficient signal to noise ratio for optical phase-change storage.

Using ab initio calculations, we have performed a study of the hydrostatic pressure effect on the equilibrium volume, lattice parameters, elastic modulus, and elastic anisotropy of selected M2AlC phases with M = Ti, V, Nb, and Ta. The deviations of our calculated volume change are lower than 3% comparing with experimental measurement, lead to a discrepancy in the bulk modulus less than 15%. Our results show a linear pressure dependence of the elastic modulus and the bulk modulus. Shear elastic anisotropy factor increase with the pressure enhancement, while the compressibility anisotropy remains constant around weak values.

The characterization and properties of InN thin films grown on GaN templates by metalorganic chemical vapor deposition (MOCVD) at various growth temperatures were investigated. Their carrier concentrations ranged from 4.6 × 1018 to 4 × 1019 cm−3and mobility valued from 150 to 1300 cm2/V s. The variation of the growth temperature brought about different growth rates. It was also found that growth rate is increased with the increasing growth temperature and reached 470 nm/h for the InN epitaxial layer grown at 675 °C. The surface roughness of InN layers was obtained from AFM measurement. The structural quality of the InN layers was determined by TEM. The surface and cross-sectional morphologies of these films are evaluated by SEM. The layer crystalline quality was investigated by means of X-ray diffraction in the rocking curves. Photoluminescence measurements performed at 7 K and room temperature gave emission peaks at around 0.7 eV.

The variable angle spectroscopic ellipsometer in conjunction with computer simulation were employed to determine the optical constants of ZnO in the ZnO/Ag/ZnO (ZAZ) multilayer system. A five-phase, glass/ZnO/Ag/ZnO/air, model was used to fit the calculated data to the experimental spectra. The ellipsometrically determined ZnO and Ag layers thicknesses were found to be agreed well with those previously determined by X-ray reflectivity. The effects of Ag layer thickness (Agd ) and ZnO top layer thickness (ZnOd ) on the optical constants of ZnO in the ZAZ multilayer system were discussed. The refractive index values determined at 550 nm, remains almost constant as Agd increases while the refractive index values decrease with decreasing ZnOd . Over the whole visible spectral range the extinction coefficient values of the Agd group are very close to zero and does not depend on Agd while the extinction coefficient values of the ZnOd group increase with decreasing ZnOd . The optical band gap values are found to be affected strongly by both Agd and ZnOd .

The use of additives which raises the density of metal-ion in electroforming solution and the application of impulse current are the common methods to improve the deposition rate of electroforming and to ameliorate the mechanical characteristics of electroforming layer. However, our study reveals that it is possible to obtain better results by tailoring the flow rate of the electrolyte and the relative intensity of the electric and applied magnetic fields. The MHD (Magnetohydrodynamic) effect arising from the application of an external magnetic field can have remarkable influence on the crystal behavior, giving more consolidated textures while providing higher deposition rate and better mechanical properties of the Ni–Co–Mn alloy.

Effects of plasma power on the growth of the multi-wall carbon nanotubes (CNTs) are reported. CNTs were grown on the silicon wafers by plasma enhanced chemical vapor deposition (PECVD) method using a mixture of acetylene and hydrogen at the temperature of 650 °C. Plasma powers ranging from zero to 35 W were applied on the samples and the effects of different magnitudes of the plasma power on the growth direction of the CNTs were investigated. Regular vertically aligned nanotubes were obtained at plasma power of 25 W. In order to set on the plasma during the growth, electrical force was applied on the carbon ions. Nickel layer was used as a catalyst, and prior to the nanotubes growth step, it was treated by hydrogen plasma bombardment in order to obtain the Ni nano-islands. In this step, as the plasma power on the Ni layer was increased, the grain size of nickel nano-particles decreased, and hence, nanotubes of smaller diameter were obtained later on. At the last step some anomalous structures of agglomerated CNTs were obtained by controlling the plasma power. Samples were analyzed by scanning tunneling microscopy (STM) and scanning electron microscopy (SEM).

A general vector approach to the polarization mode dispersion (PMD) and polarization dependent loss (PDL) calculation in a cascade of optical components with each component having both PMD and PDL is presented. By using the formalism, the PMD-PDL coupling effect is quantitatively described and its implications are discussed. In particular, it is shown that the presence of PDL in the components is a second-order effect in the PMD of the cascade. As an illustration of the formalism, a statistical estimation of PMD and PDL in a practical optical device is performed. The accuracy and the computational advantage of the vector approach are demonstrated.

Hysteresis behavior of magnetic force versus gap between a high-T c superconductor and a magnet, in static and dynamic cases, is studied numerically. Differing from the previous methods, based on macro electromagnetic constitutive relation of superconductors and Maxwell equations, a numerical method with the finite element method (FEM) is established. After numerical code is examined by comparing between numerical and experimental results of the relation of magnetic force-gap, the hysteresis curves of magnetic force-gap including major and minor loops in static case are simulated, and furthermore the dependences of major loop on main parameters including the critical current density and the thickness of superconductor, the residual magnetic field of magnet, and the diameter ratio of superconductor to magnet are studied numerically. In the case of free vibration, by investigating dynamic response of levitated body at different levitation/suspension positions in this magnetic levitation system, we obtain the corresponding results of the variation of magnetic force with gap. All the numerical results of the relation between magnetic force and gap show the strongly nonlinear and highly hysteretic behavior.

The efficiency of iron-catalysts in hydrocarbon decomposition, aimed at growth of carbon nanotubes by chemical vapour deposition (CVD), is systematically investigated. The synthesis reaction is carried out at different temperatures (873–1123 K), for various durations (0.5–6.0 h), using diverse precursor gases (C2H6 or C4H10) and catalyst supports (SiO2 or Al2O3). A large variety of experimental conditions is explored by varying amount (0.5–2.0 g), metal load (20 wt.% and 29 wt.%) and annealing temperature (723–973 K) of the catalysts and by considering different gas flowing setups, namely, by changing flow rate (100–240 cc/min) and composition (H2/precursor/He, with He at 0–63%) of the gas mixture, flow-rates and flow-ratio of reactant gases (H2: 0–120 cc/min; Precursor Gas: 15–120 cc/min; H2/PG: 0–3). Iron catalysts encapsulation is shown to be the main factor limiting C yields in the cases considered, and its changes to be responsible for the broad yield variations (20–910 wt.%) observed. The results of analyses, carried out by Raman spectroscopy (RS) and complementary diagnostics techniques, demonstrate the need of accurately tuning the manifold growth parameters, in order to fully benefit of the advantages potentially deriving from a proper choice of precursor gas and catalyst-support material.

We present electromagnetic invisible cloaks and concentrators whichare composed of inhomogeneous and anisotropic metamaterials with asquare-shaped outer boundary and a circular-shaped inner boundary.Using the technique of coordinate transformation, closed-formformulations of the permittivity and permeability tensors have beenderived for the metamaterials to realize the invisible cloaking andto concentrate electromagnetic waves. Full-wave simulation resultsare given to validate the non-rotationally invariant cloaks andconcentrators.

The mechanical and structural properties were studied at room temperature for Al-2wt.%Ag and Al-2wt.%Ag-1wt.%Sn alloys 503 K–583 K. The variation in the internal friction, Q −1, dynamic Young's modulus, Y, Vickers hardness, H v , and X-ray diffraction patterns were obtained. For 533 K the internal friction showed abrupt increase while Young's modulus and Vickers hardness showed minima. The results showed a remarkable dependence of the measured parameters on both Sn addition and the heat treatment regime.

In the French watt balance experiment, in order to have a single point of application of a weight and an electromagnetic force balancing this weight, a system of double gimbals with flexure pivots was made out of copper-beryllium alloy. This allows the articulation of the suspension devices of the mass (generating the weight) and coil (on which the electromagnetic force acts) around four coplanar axes which intersect at one point (equivalent to a virtual centre of rotation). The study of the free dynamic behaviour under vacuum of this device dealt with resonance, damping due to internal friction of the material and coupling between the two systems of gimbals. The results obtained show that this novel device presents suitable characteristics for concentrating two different forces at a single point and aligning them around a common vertical axis. It can be used not only for watt balance experiments but also for any other mechanical applications where alignment and concentration of two forces are necessary.

In this paper, we present a new analog set-up for non linear dielectric measurements. The device is based on the auto-balanced bridge principle used in impedance analyzers. Its main advantage is to operate at high frequencies in comparison with a classical current amplifier. This extension consists in extracting the harmonics of a non sinusoidal current crossing the material. The set-up is used to perform non linear dielectric measurements on a ferroelectric liquid crystal and shows better performances than a previously published digital set-up.

We present a derivation of the time evolution equation of aphysical quantity defined as an integral of a density over a movingsurface. The equation can be readily used to obtain the transportequation for an interfacial entity such as surfactants on thesurface of a single-valued interface as in thin films. By utilizingthe concept of the extension field of the density we generalize thetransport equation to the case of multi-valued interfaces.