Investigation the effects of electron scattering in boron hexogonal nitride (h-BN) was performed. At present, material h-BN, together with graphene, is considered to be one of the most promising materials for the formation of new semiconductor devices with good characteristics for the ranges of ultrahigh and extreme high frequency bands. The main electrophysical parameters and characteristics of h-BN was considered. For this material the three valley K-M-Г band structure has been used. It is noted that the K valley has the smallest energy gap between the conductivity zone and the valence zone. Calculation of relative electron masses and parabolicity coefficients in K, M and G valleys was performed. Formulas that allow to model the main electron scattering intensities in h-BN were presented. The obtained electron scattering intensities as a function of energy and temperature were considered and analyzed. Based on the obtained characteristics, it was possible to implement a statistical multi-particle Monte Carlo method to determine the characteristics of electron transfer in the heterostructure of a semiconductor devices containing layers of hexogonal boron nitride.

Nanostructured magnetic composites based on carbon nanotubes (CNTs) and ferromagnetic nanoparticles (FNPs) are of great interest both from an applied and fundamental point of view. In particular, one of the features of CNTs with FNPs is the possibility of magnetic interaction of nanoparticles through the conducting medium of CNTs. For a detailed description of this special type of interaction, which is the indirect exchange coupling, it is necessary to establish the relationship between the macroscopic and microscopic parameters of the physical system. In nanostructured ferromagnets, these dependences are described within the framework of a random magnetization model in which the spin system and, consequently, the main macroscopic characteristics (coercivity, susceptibility, and saturation magnetization) are determined by such microscopic parameters as the exchange interaction constant, the FNP magnetization, the local magnetic anisotropy constant, and the grain size. In this paper, on the basis of the previously obtained microscopic parameters of CNT – FNP nanocomposites, the possibility of obtaining long-range magnetic correlations through the indirect exchange coupling (IEC) between FNP embedded inside a multi-wall CNT (MWCNT) is considered. A model Hamiltonian is used that takes into account the diameter, chirality, chemical potential and spin-orbit interaction (SOI) in the system. The reason for the appearance of a noticeable SOI in CNTs is the curvature of the tubes, which significantly increases the SOI compared to graphene, as well as possible defects and the presence of FNP. IEC is realized by means of p-electrons of the inner wall of the MWCNT. The propagation of the spin susceptibility along the MWCNT axis is calculated and it is shown that a long-range magnetic order is realized under the condition that the chemical potential enters the gap opened by the SOI. Coherence is realized at distances up to micrometers. The proposed approach also made it possible to estimate the energy of the exchange interaction between the FNP belonging to one CNT. The results obtained indicate the prospects for the use of CNT– FNP nanocomposites in carbon spintronics.

The effectiveness of biofeedback based on the electrodermal activity of the skin for the development of the relaxation skill of drivers and assistants of drivers of locomotive crews of the Belarusian Railways was investigated. The experiment was carried out on the basis of the office of the psychological service of the Motor Car Depot in Minsk. A personal computer and a NeuroDog hardware and software complex were used as equipment for the biofeedback training. Based on the results of the biofeedback training, three groups of drivers were identified with varying degrees of successful development of the relaxation skill. We analyzed the differences in psychophysiological and personal characteristics between three groups of test drivers and locomotive crew assistants with varying degrees of ability to voluntarily regulate their functional state. For the analysis, we used the data of psychophysiological examination using the UPDK-MK complex for professional psychophysiological examination and selection of railway workers (Neurokom, Russia) and data obtained by the method of functional biocontrol with biofeedback (NeuroDog, Neurokom, Russia). To identify differences between the groups of subjects, the nonparametric Kruskal – Wallis H-test was used. The calculations were performed in the electronic package Statistica 10.0. Statistically significant differences are shown between groups with different degrees of success in developing the relaxation skill by indicators: concentration of attention, the sixth octant of intrapersonal relationships “dependent – obedientˮ, the time to complete the task of assessing emotional stability, and factor G of the methodology of RB Cattell “low – high normative behaviorˮ.

The purpose of the article is to describe the methodology for obtaining the structure of the optimal controller, which guidances the aircraft to the target point along a hyperbola, using the Time Difference of Arrivals (TDoA) from two navigation positions on the plane. A feature of this system is that one TDoA measurement does not allow to fully describe the position of the aircraft on the plane, but only describes the position hyperbola. The guidance problem is solved by choosing a proper hyperbola passing through the target point and letting the aircraft move along this hyperbola to the target. This paper considers the application of the method of synthesis of an aggregated controller to obtain a nonlinear guidance law. This made it possible to take into account the properties of the control object to a larger extent. Computer simulation has shown the effectiveness of the expressions obtained.

The effect of the systematic component appearance (deceleration and acceleration) during asynchronous electron interaction with an inhomogeneous electromagnetic field suggests not only the academic interest [1–4] (as a new physical phenomenon), but can also have practical usage in special microwave generators of various ranges. Earlier, the following types of devices were proposed: a coaxial diode generator-diotron [5] and a spherotron based on a two-spherical resonator [6, 7]. Along with some advantages, these devices have a significant disadvantage: the frequency tuning of such generators is difficult due to the fixed resonator oscillation type by the given geometry. This article proposes and analyzes a new type of spherotron, the resonator of which consists of a coaxial line segment loaded on a two-spherical capacitor, in which the interaction between radially converging electron beams and an increasing radial electric field of the resonator run. In the coaxial line (the inductive resonator component) there is an impedance transformer (adjustable waveguide transformer with two dielectric plates) [8] consisting of movable quarter-wave washers. Their movement togather changes the resonator frequency and the mutual moving towards and away from each other is the relation with the load. The coaxial line is connected by the pin to the output waveguide. The proposed spherotron calculation showed the possibility of achieving an efficiency of up 30 % and being tuned in the given band of up 30 % with changing the accelerating voltage V0 = 1.12 V. This generator type is demanded in special (small-sized) communication systems, Doppler radar, electronic warfare with frequency tuning [9], in biochemical research and technology [10], in biological research [11], and in molecular synthesis.

In the modern world, the data used to describe objects is often presented as sparse vectors with a large number of features. Working with them can be computationally inefficient, and often leads to overfitting; therefore, the data dimension reduction algorithms are used, one of which is auto encoders. In this article, we propose a new approach for evaluating the properties of the obtained vectors of lower dimension, as well as a loss function based on this approach. The idea of the suggested loss function is to evaluate the quality of preserving the semantic structure in the embedding space, and to add that metric to loss function to save object relations in the embedding space and thus save more useful information about objects. The results obtained show that using a combination of the mean squared loss function together with the suggested one allows to improve the quality of the embeddings.

This paper introduces functional approximations to the MIMO capacity over flat Rayleigh fading channels, which allow for analytical solutions to network resource optimization problems. This approximation allows to solve the problem of resource allocation optimization in radio networks and in other systems used to transfer information. The precision of the suggested approximations is assessed and is shown to provide a very close match to the exact capacity expression.

The article contains a description of the model and approach for determining the weights of controls (other objects) based on a matrix of pairwise comparisons. The initial data in the matrix of paired comparisons implicitly specify interval estimates for comparison of controls. Interval estimates can be constructed relatively easily using Harrington's fuzzy metric scale. A heuristic method for determining the priorities of controls is proposed, which seeks to obtain weights (priorities) of controls that deviate minimally from the boundary values of the weight intervals.The latter are easy to find using the system of relations, on the basis of which the matrix of pairwise comparisons of controls is built. To assess the statistical adequacy of the found control priorities, the determination coefficient is used, the value of which at the level of 80 % and above is considered practically acceptable for applications. The critical value of the coefficient of determination can be determined, for example, using the Fisher criterion. If the conditions of statistical adequacy are not met, the initial data in the matrix of paired comparisons should be revised. An example is provided to illustrate the method described in the article. The main advantages of the approach described in the article are the flexibility of the choice of interval estimates for pairwise comparison of controls, the relative simplicity of computational calculations, and the ability to control the calculation results using statistical criteria. The described method develops the authors' approach to the adoption of anti-crisis management by adapting management priorities to the conditions of the production system and its environment.

Actual stage of meter waveband radar evolution is the design of mobile radar with improved surveillance functions, as well as signal generation and processing. Such radars measure coordinates of aircraft in 3D space with adaptive change of operation frequency, parameters of probing signal, and polarization. Except radiolocation tasks, such radars allow to carry out integral information processing, EM analysis, ELINT, as well as jamming and clutter canceling, and must have height mobility and secrecy properties. The achievement of these properties is possible due to the application of digital antenna arrays with digital solid-state Tx/Rx modules, modular construction of all radar subsystems, digital beamforming technology, adoptive algorithms of space-time, and statistical processing of received signals. The prototype of meter-wavelength band radar system with height effectivity and informativity of radiolocation receiving, with the capability of fast moving and deploying is review in this article. The proposed radar system allows to provide measuring coordinates of an aircraft in 3D space, large distance detection, tracking and targeting of all types of aircrafts (including stealth aircrafts), carry out integral processing of radiolocation information, ELINT, EM analysis, as well as jamming and clatter canceling.

The purpose of the research is to study the charging-discharging characteristics of a hybrid energy storage device which consists of two parallel connected battery and capacitive parts to assess the work efficiency of its circuit design as a part of standalone photovoltaic system. The charge current kinetics of a hybrid storage device from a solar panel was carried out under natural conditions at a specific power of incident solar radiation of 800–850 W/m2. The discharge current kinetics of battery and capacitive storages were obtained with a resistive load and disconnected solar battery. The dynamics of charging and discharging processes of the battery and capacitive parts of the energy storage device were monitored by the voltage rise/fall rate. The battery part of the drive is charging and starting the device based on a lead-acid gel battery with a charging capacity of 11 A·h, 12.8 V maximum voltage, and 15 A maximum discharge current. The capacitive part consisted of a new generation INSPECTOR Booster supercapacitor starting the device with an electrostatic capacity of 80 F, 15.5 V voltage, and 800 A starting current. As the energy source a solar battery was used, with a 12 V nominal voltage and 100 W peak power. A 6 Om rheostat with 15 A consumption current was used as a load during the storage device discharge. A Morningstar ProStar-15 charging/discharging controller with a pulse-width modulation function was used to monitor and control the photovoltaic system. Quantitative charging and discharging characteristics of a battery-capacity energy storage device were obtained for the use in the development of standalone photovoltaic system.

Currently, ensuring information security of object fiber-optic data transmission systems is an important and urgent task. Therefore, the purpose of this article is to develop an easy-to-implement method for protecting object fiber-optic data transmission systems from unauthorized access to information. This work proposes an easyto-implement method for protecting object fiber-optic data transmission systems from unauthorized access to an information signal, based on weakening the power of this signal. It is shown that the use of the proposed method will not lead to a significant decrease in the data transmission rate in the object fiber-optic data transmission systems, but will increase its information security. The theoretical limit of signal decoding for data transmission technologies over optical fiber Ethernet has been determined. It was found that the lowest value of the theoretical limit of signal decoding corresponds to Fast Ethernet technology (100Base-FX). It was found that when the value of the attenuation coefficient of optical radiation D > 20 dB, the data transmission using Fast Ethernet technology (100Base-FX) is terminated. The results of this article can find application in the means of technical protection of information transmitted over object fiber-optic data transmission systems.

The work shows a significant effect of the focusing magnetic field on the output characteristics of the klystron. When the calculations are done using nonlinear one-dimensional models, optimization of the parameters makes it possible to obtain versions of devices with the efficiency of 0.8 – 0.9 and higher. However, when testing these options using nonlinear two-dimensional models that take into account the radial motion of electrons, there is a significant discrepancy in the output characteristics obtained from the one-dimensional and two-dimensional models. This is due to the fact that during the motion of the electron beam, the radii of the leading centers of the large particles change the coefficients of interaction of the particle fields with the electromagnetic fields of the resonators change, which leads to a change in the output characteristics of the klystrons: efficiency, output power, and gain. On the other hand, it seemed that setting a large focusing magnetic field to exclude the radial motion of particles could eliminate this drawback, however, another problem arises here - the magnetic system for focusing becomes unacceptably large and it is technically difficult to obtain magnetic induction values of more than 2 T (the weight of the magnetic system can be several hundred kilograms). Therefore, one should choose the magnetic field induction for focusing the electron beam no more than 1T. In this paper, a twodimensional nonlinear mathematical model (2.5D) is proposed that takes into account the azimuthal component in the equations of motion. In the model, the induction of the focusing magnetic field is set in the form of tables. This makes it possible to set the inhomogeneity of the magnetic field at any place in the interaction space of the klystron. The calculation of a powerful relativistic klystron with an accelerating voltage of 1000 kV and the beam current of 250 A was carried out. The use of an inhomogeneous magnetic field makes it possible to reduce the deposition of electrons in the region of the gaps. Therefore, a decrease in the electron deposition leads to an increase in the durability of klystrons.