Structural and Transport Properties of Hg1-xCdxTe/CdTe Semiconductor Heterostructures

Terbium activated gadolinium oxysulphide phosphor (Gd2O2S:Tb) shows bright green luminescence and high efficiency under X-ray excitation. Phosphor utilisation depends on powder characteristics and luminescence properties that are regulated during the synthesis stage. The paper presents some of our new results on the synthesis of Gd2O2S:Tb phosphor by solid-state reaction route from oxide precursors. Efficient luminescent powders utilisable in the

Aerogels are highly porous materials that are produced via sol-gel processing and supercritical drying. Titanium dioxide aerogels were prepared using a variety of sol composition from the system Ti(OC3H7)4 / H2O/ EtOH / HNO3. The morphology of titanium dioxide aerogel was characterized by krypton adsorption, X-ray diffraction, scanning and transmission electron microscopies. The surface area, pore volume and pore size distribution of TiO2 aerogels

The relation between the critical value V*; of the barrier layer voltage and the mean coordination number of the oxygen in the first coordination sphere around the aluminium atom was investigated in order to illustrate the transition from conventional to hard anodization. The modification from open to closed structure is very sharp in the neighbourhood of V*;.

Fourier analysis of EXAFS data, a self-contained fortran program-package has been elaborated.

The effects of the thickness of thin electrodeposited palladium layers on the kinetics of hydrogen desorption processes are reported. Measurements have been performed with a piezoelectric quartz crystal microbalance under dynamic conditions, at a constant temperature of 61.1 ± 0.05 °C, and three different hydrogen-equilibrium pressures (α-phase region). From the kinetic analysis of desorption data, the desorption rate constants for the first-order

The influence of crystalline microstructure upon the apparent diffusion coefficient of hydrogen in Pd samples are reported. The apparent diffusion coefficient was measured by the galvanostatic permeation method (at 20°C), while the structure was characterized by X-ray diffraction measurements. Pd membrane electrodes of different thicknesses, l = 5 × 10−3cm and l = 10−2cm, were used. The structure of Pd membrane electrodes was changed by successive

The hydrogenation of the alloy of composition CaMg1.8Ni0.5 containing CaMg2 and MgNi2 shows fast activation kinetics. The Mg2Ni phase is observed in the dehydrided samples. The three plateaus on the hydrogen desorption isotherms correspond to the most stable magnesium hydrides observed up to now in Mg-alloy (ΔH = 20–24 kcal/mol H2). The effects of Ca additions on the hydrogen storage capacity and desorption rates of some Mg-rich alloys have been

The pressure-composition isotherms for the systems LaNi5-H2 and LaNi5-D2 have been measured both for absorption and for desorption in the temperature range - 10 to +65 °C. The ratio of the plateau pressures, View the MathML source, is r < 1 at high temperatures, and becomes r > 1 at lower temperatures, depending on the thermal treatment of the sample. From the plateau pressures at a constant hydrogen (or deuterium) concentration in LaNi5 (3D or

The substitution of chromium for vanadium in ZrV1.5-x Cr x Ni 1.5 leads to a cubic C15 phase as the main phase with a low content of the secondary phase Zr7Ni10. The lattice parameters suggest a complex redistribution of V, Ni or Cr between the B and A sites of the Laves phase AB2, which does not depend only on the Cr content. The pressure-composition isotherms show sloping plateaux, alloy hydrogen contents between 3.35 and 4.25 H/mol and desorption