Thermoelectric and photoelectric properties of the p-n CuInSe2/CdS heterostructures obtained by the quasi-equilibrium deposition method

Through deposition of CuInSe₂ films on CdS substrates in a quasi-closed-circuit “hot-wall” reactor, p-n CuInSe₂/CdS heterostructures were obtained. The thermoelectric power, current-voltage characteristics, and photosensitivity spectra of the structures were investigated.     

Simultaneous measurement of the velocity of an ultrasonic shear wave and the thickness of a test object with plane-parallel boundaries using two antenna arrays

Methods for the determination of the unknown velocity of the propagation of shear US waves and the unknown thickness of a test object were considered. Two antenna arrays working in the double-scanning mode, where echo signals are recorded, which were emitted and received by all pairs of antenna-array elements, were suggested. Antenna arrays on prisms were mounted on the test-object surface towards each other. An algorithm for the treatment of measured echo signals was designed using a method that is similar to the least-squares method. The use of the algorithm enables one to simultaneously determine the sound velocity and thickness of a test object with plane-parallel boundaries with an exactness greater than 0.5%. In this article, the factors were studied that affect the exactness of measurements and methods of their elimination or minimization. The results of numerical experiments and the use of the method on three samples relative to measurements using an IN-5101A instrument are given.     

Some properties of modified polyacrylonitrile fibres

Fibre-forming copolymers of acrylonitrile and a monomeric quaternary ammonium salt, β-methacryloylhydroxyethyl-(N-dimethyl,methylene)ammonium iodide, were obtained by wet spinning and their physicomechanical and structural properties were investigated. It was found that the modified fibres have a set of valuable properties in comparison to the industrial fibre Nitron.     

Interaction of radiation defects with nickel atom clusters in silicon

Based on infrared microscopic studies, we show that clusters of impurity nickel atoms are uniformly distributed over the entire volume of the silicon crystal; by varying the density of the clusters in silicon exposed to γ-radiation, it is possible to control the concentration of the electroactive atoms and the structure of the nickel clusters. It is shown that the presence of clusters in the lattice significantly increases the radiation resistance of the silicon.     

Thermal conductivity of Sn<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>Nd<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>S single crystals

The thermal conductivity of Sn_{1 − x} Nd _x S (x = 0, 0.001, 0.002) single crystals has been measured in the temperature range 80–840 K. The results have been used to evaluate the electronic and lattice components of the thermal conductivity. Both the electronic and lattice components are shown to decrease with increasing temperature and to increase with neodymium content.     

Dynamics of the defects recharging in coarse-grained p-CdTe films

The capacitance-voltage characteristic of the MOS-structure based on the coarse-grained p-CdTe film is studied. The nonmonotonici character of the characteristic is attributed to the recharging of deep acceptor levels at the semiconductor-oxide interface and by the variation in the degree of compensation of surface states.     

Drug resistant tuberculosis in prisons in Azerbaijan: case study

Tuberculosis is a significant health problem in Azerbaijan. In prisons, this problem is compounded by overcrowding, poor general health, a high representation of risk groups, late case finding, and incomplete treatments. The present study investigated the extent of drug resistance at the Central Penitentiary Hospital in Baku--the country's only treatment center for prisoners with tuberculosis. This International Committee of the Red Cross program, established in 1995, uses the directly observed treatment, short course (DOTS) strategy. Sputum samples were collected from two groups of prisoners: 1) 28 patients who failed to respond, clinically or bacteriologically, after a minimum of 8 weeks to the treatment regimen recommended by the World Health Organization and 2) 38 patients consecutively enrolled over a 4-week period from whom sputum was taken before the start of treatment. Mycobacterium tuberculosis was isolated from all 66 sputum specimens. In the first group, 25 strains (98%) were multidrug resistant (to rifampicin and isoniazid). Such resistance occurred in all new cases and 14 (82%) of the 17 failure or relapse cases. In the second group, 9 strains (24%) were multidrug resistant and only 12 (32%) were fully susceptible. This resistance was found in 3 strains (15%) among the 20 new cases and in 6 strains (33%) among the 18 cases of treatment failure or relapse. These findings suggest that prisoners may have an important future role in the transmission of tuberculosis, especially multidrug resistant forms, in the former Soviet Union.     

Phase equilibria in Ag-Ga-S films and kinetics of AgGaS<Subscript>2</Subscript> crystallization

The phase compositions of films produced by coevaporation and sequential evaporation of Ag, Ga, and S have been determined. The phases identified in the films grown at room temperature are Ag₂S, GaS, Ga₂S₃, and AgGaS₂. The kinetics of phase transformations in thin amorphous AgGaS₂ films have been studied by dynamic electron diffraction. The dimensionality of growth during amorphous AgGaS₂ crystallization and the activation energies for nucleation and crystallite growth have been evaluated.