A method of determining stoichiometry deviation in cadmium and zinc chalcogenides that is based on the temperature dependence of the ratio of components partial pressures during evaporation of solid compounds in a limited volume has been suggested. The new method differs from methods implying the collection of excessive component during evaporation in large volumes. The method includes measuring vapor phase components partial pressures during material heating to above 800 K, solving a set of material balance equations and the electric neutrality equation, and calculating the stoichiometry deviation in the initial compound at room temperature. Intrinsic point defect concentrations are calculated using the method of quasichemical reactions. The independent variables in the set of equations are the sought stoichiometry deviation, the partial pressure of the metal and the concentration of free electrons. We show that the parameter of the material balance equation which determines the method’s sensitivity to stoichiometry deviation, i.e., the volume ratio of vapor and solid phases, can be considered constant during heating and evaporation unless this parameter exceeds 50. If the partial pressure is measured based on the optical density of the vapors, then the sensitivity of the method can be increased to not worse than 10^-6 at.%.

The phase composition and heat conductivity of (ZrO₂)_0.9(R₂O₃)_0.1 solid solution single crystals have been studied, where R = (Gd, Yb, Sc, Y), (ZrO₂)_0.9(Sc₂O₃)_0.09(Gd₂O₃)_0.01 and 
(ZrO₂)_0.9(Sc₂O₃)_0.09(Yb₂O₃)_0.01. Single crystals have been grown by directional melt crystallization in a cold skull. The phase composition of the crystals has been studied using X-ray diffraction and Raman spectroscopy. The heat conductivity of the crystals has been studied using the absolute steady-state technique of longitudinal heat flow in the 50—300 K range. We show that at a total stabilizing oxide concentration of 10 mol.% the phase composition of the crystals depends on the ionic radius of the stabilizing cation. The (ZrO₂)_0.9(Sc₂O₃)_0.1 crystals have the lowest heat conductivity in the 50—300 K range while the (ZrO₂)_0.9(Gd₂O₃)_0.1 solid solutions have the lowest heat conductivity at 300 K.
Analysis of the experimental data suggests that the heat conductivity of the crystals depends mainly on the phase composition and ionic radius of the stabilizing cation. Phonon scattering caused by the difference in the weight of the co-doping oxide cation has a smaller effect on the heat conductivity.

 The method of mathematical modeling was used to calculate the temperature distribution in bifacial solar cells. It has been established that the differences in the configurations of the photovoltaic generator lie only in the fact that in a double-sided element, a greater outflow of heat comes from the back side. At the same time, bifacial solar cells demonstrate increased generation of electrical energy. The calculations performed confirm the validity of the choice in favor of two-sided solar cells, which is important when using the developed configuration of a photovoltaic generator. Based on the analysis of the technologies available on the market for photovoltaic conversion of solar energy into electricity, a configuration of a photovoltaic generator based on bifacial heterojunction silicon solar panels was developed. The developed configuration is a moving platform with a photovoltaic system installed on it, equipped with a light flux collection system.
A 2-axis servo system has been developed for the general case of flat mounting of solar modules. The drive with a travel range of 350 mm is installed in the north-south direction, 450 mm — east-west. The task was to find the right shoulder to ensure symmetry and the maximum angle of rotation along the axis. As a result, solutions were determined for the north-south and east-west directions.
In addition, on the basis of a microcontroller, a circuit diagram of a device was developed that provides a given control algorithm for a solar tracker. Also, the scheme includes a GPS/GLONASS module to obtain the exact coordinates of the installation location and time synchronization.

Carbon nanotubes are one of the currently sought after nanotechnology materials. But the issue of controlling their physicochemical properties, in particular, for creating nanowires by intercalating metal atoms in them, has not yet been fully studied. In this case, there is an effective way to control the electronic energy characteristics — the introduction of impurity atoms. Boron is the most effective among this class of substituting elements. Therefore, the purpose of this article is to study the possibility of internal filling of carbon nanotubes with impurity boron atoms with various metal atoms and to determine the role of its concentration on the phenomena occurring in this case. Using the density functional theory, a model experiment was carried out on the introduction into the cavity of a nanotube of aluminum atoms, as well as alkali metals - lithium, sodium and potassium. The model experiment showed that in all cases the formation of a stable adsorption complex takes place, which can be considered as a model of a nanowire with multiple filling with atoms between the nanotube and metal atoms. At the same time, it was found that during the formation of complex compounds “nanotube — metal atom”, the electron density is redistributed in the system, namely, it is shifted from the B atoms of the metals to the surface of the nanotube, which leads to the formation of additional charge carriers transferred from the donor. Also, an analysis of the electron-energy structure made it possible to establish that the band gap for BC₃ nanotubes narrows during the intercalation of metal atoms. This conclusion is extremely important for the needs of nanoelectronics, since it makes it possible to predict the more efficient use of carbon nanotubes with a higher concentration of impurity boron atoms to create nanodevices due to the appearance in them of conducting properties that are different from pure nanostructures, which are expressed in the appearance of additional charge carriers.

A method for the formation of metal nanoparticles in a localized volume with a high energy density due to the flow of a pulsed electric discharge and the effect of cavitation has been studied. The mechanism of formation of energy inhomogeneities, which provides the generation of nanoparticles with high specific energy intensity, is considered. The formation of dynamic heterogeneity is carried out in three stages. There is a breakdown of the interelectrode space and the formation of a vacuum volume, which is filled with a vapor-gas medium. As a result of an increase in pressure in the bubble, a pulsed gas discharge is ignited, which leads to the generation of metal nanoparticles. As a result, there is a localized volume in which the energy in the discharge reaches a value of up to 10⁶ K. The growth of energy in the bubble leads to its collapse and metal nanoparticles pass from a medium with high energy (10⁶) into water at room temperature, which leads to their hardening. Particularly pure nanoparticles of various metals with a size of 5–15 nm are obtained, which can be grown on a single-crystal silicon surface at room temperature and positioned on the surface of porous materials and products of complex configuration.

Single-layer Ta-Si-C-N films on fused quartz substrates were made by direct current magnetron sputtering. The structural perfection of the film was investigated by X-ray diffraction analysis, scanning electron microscopy and optical emission spectroscopy of glow discharge. The optical parameters of the films were determined by the method of multi-angle spectrophotometry. Spectral dependences of the transmission coefficients of substrates and structures at normal light incidence in the wavelength range of 200—2500 nm are obtained. It is shown that the transmission spectrum of the sample has an oscillating character, which is caused by interference phenomena characteristic of layered structures. Spectral dependences of the reflection coefficients of films and substrates in the wavelength range of 200—2500 nm at small angles of incidence of light are obtained. By the magnitude of the difference between the reflection coefficient at the maximum of the interference of the film and the corresponding reflection coefficient of the substrate at the same wavelength, it is shown that the absorption in the film is low. A formula is obtained for determining the absorption coefficient of a film from the measured parameters. Based on the experimental data obtained, spectral dependences of the absorption coefficients of the substrate, structure and film are constructed. The method of reflection at two angles of incidence, based on the determination of the position of the interference extremes on the spectral dependences of the reflection coefficients, calculated discrete values of the refractive coefficients in the wavelength range 400—1200 nm. The obtained values are approximated by the Cauchy equation. The film thickness was calculated, which was d = 1046 nm ± 13%. Spectral dependences of the film attenuation indices with and without reflection are constructed. A summary table is presented with the obtained values of the refractive coefficients and absorption indices with and without reflection.

A combined method of profound purification of Cd, Zn and Te developed by the Authors and allowing one to produce high-purity materials in a vertical reactor unit has been considered. The method includes the following processes: filtration refinement of metal alloy with the possibility of its vacuum degassing and additional purification through an oxide layer; first distillation with the possibility to use gettering additions in the melt and gettering filters; melt degassing with the removal of highly volatile impurities to the condenser in rough vacuum; second distillation and metal casting for weighed quantities. The Authors have developed and produced a test model of the unit for the experimental profound purification of metals using the method developed herein. Physical experiments have been conducted for obtaining 99,9999 wt.% purity Cd, Zn and Te for 30 residual impurities with a product yield of at least 55%.