Features of Recombination Radiation of GaAs Type Semiconductors with the Participation of Fine Acceptor Levels in a Magnetic Field

Using the method of Picus and Beer invariants, general expressions are obtained for the total intensity I and the degree of circular polarization Рcirc.of the luminescence of GaAs-type semiconductors with the participation of shallow acceptor levels in a longitudinal magnetic field H. Special cases are analyzed depending on the value and direction of the magnetic field strength, as well as on the constants of the g-factor of the acceptor g1,g2and the conduction band electron ge. In the case of a strong magnetic field H// [100], [111], [110], a numerical calculation of the angular dependence of the quantities I and Рcirc.was performed for some critical values of g2/g1, at which Рcirc.exhibits a sharp anisotropy in the range from −100% to +100%, and the intensity of the crystal radiation along the magnetic field tends to a minimum value.

Simulating the Dynamics of Bimetallic Clusters Deposited onto a Surface Using Molecular Dynamics

This paper examines the interface development between a single crystalline Ag matrix and core-shell AgnCom nanoclusters that have been deposited with energies varying between 0.25 eV and 1.5 eV per atom using computer modeling techniques. Clusters undergo deformation as a result of the slowing down;they may also become epitaxial with the substrate and maintain their core-shell structure. A detailed analysis of the effects of the cluster-surface interaction is conducted over a realistic size and energy range, and a model is created to show how clusters accumulate. It is discovered that both the silver shells and the cobalt cluster cores exhibit limited epitaxy with the substrate, and that the contact produced is only a few atomic layers thick. The effect is higher for Ag shells than for Co cores, and it is not very energy dependent.

Changing the Air Parameters in the Cotton Pneumatic Transport Pipe

This scientific article examines the issue of changes in the density and speed of the airflow in the pipeline pneumatic conveying equipment used in ginneries, analyzes the causes of changes in the density and speed of air.

Surface Quantum-Dimensional Photocarrier Recombination in CdTe Microcrystals

The scope of the study is the spectra of low-temperature (T = 2K) photoluminescence of a p-CdTe/n-CdS film heterostructure comprising a monolayer of CdTe microcrystals, where a single microcrystalline particle is typically one micron in size. Focus is made on the dominant band of “super-hot” emission appearing in the spectral region located in energy above the fundamental absorption edge of a CdTe bulk crystal. A theoretical model has been developed that assumes the existence of a space-charge layer inside a microcrystal, which leads to the formation of a triangular potential well for an electron near the surface. The anomalous emission band arises as a result of the optical transitions of electrons from near-surface levels of spatial quantization to valence band states.

Photo Thermal Generator of Selective Radiation Structural and Energetic Features

Photo thermoelectric generators (PTEGs) are solid state heat engines that generate electricity from concentrated sunlight. In this paper, we developed a novel detailed balance model for PTEGs and applied this model to both state-of-the-art and idealized materials. This model uses thermoelectric compatibility theory to provide analytic solutions to device efficiency in idealized materials with temperature-dependent properties. The method for the theoretical calculation of the mechanism of absorption and refraction of light radiation of a selected wavelength in the volume of a photoelectric converter and the design of an effective photo thermal converter with a fixed slit are presented in the article. Direct- and non-direct-electron transitions from the valence band to the conduction band are analyzed. The possibility of optimal distribution of the light spectrum on the frontal surfaces of the solar cell and thermoelectric converter is shown. According to the results of experimental studies, a conclusion was made that the efficiency of a photo converter increases by a factor of three as compared with analogues, but operating without a thermal converter.

Highly Efficient Conversion of Solar Energy by the Photoelectric Converter and a Thermoelectric Converter

The analysis of the principle operation of the solar element is given in the work. The efficiency of the creation of combined high-efficiency converters of network energy in electric and thermal is indicated. A method for creating a combined photo thermo converter with a high value of the efficiency of a solar element has been found. A method for separating light from optical lenses is shown. The calculation of the light intensity into diffraction pattern is calculated using the Huygens-Fresnel principle. A new design of a highly efficient combined light-thermal converter into an electrical, with a solar element, operating on selective photoactive radiation is presented. The process of conversion of non-active radiation into electrical radiation by means of a thermo electronic converter is described. The ways of the solution of the problem connected with the reduction of the coefficient of its full effect as a function of temperature and characteristics are indicated.

Theoretical Optimization of the Production of Heating Layers Using Local Wool Fibers

Science is the basis of the country’s development and wealth. In particular, it is necessary to effectively use advanced scientific developments and technical achievements in order to strengthen the economy in the period when the desire for innovation in all fields is still growing. In theoretical-experimental Scientific Research work, both theoretical and experimental results are achieved, and it is more useful to withstand more theoretical-experimental loads for a longer period of time. The occurrences in the production process of natural wool fiber technologists are a complex of physical and mechanical phenomena, which can be used only by the modern achievements of science and technology. In most cases, the parameter relationship with the factors influencing the technological process or the object can open a curve without any other things.

Investigation of Changes in Flow Parameters along the Transport Line in Installations for Pneumatic Transport of Cotton

The article presents the results of a study of changes in the parameters of the flow, velocity and pressure of air along the cotton transportation line in pneumatic transport installations and their dependence on the parameters of the pipeline. The purpose of the research is to theoretically substantiate the choice of the pipeline diameter depending on the properties of the material (cotton), the required processing capacity and pipeline throughput. In the research, an analytical method was used to study changes in the pressure of the air flow along the transportation line at different pipeline diameters. It is established that, according to the existing calculation method, the flow pressure along the transportation line is reduced to zero. At the same time, various scientists have proposed various analytical and empirical dependencies, which, in turn, give different ideas about the resistance of the inner surface of the pipes to the movement of air and material flow and do not describe the real situation, especially when transporting material from a long distance. This requires in-depth theoretical and applied research to establish real patterns of changes in flow parameters along the material (cotton) transportation line.