The investigations of a multilayer material – a polymeric radio-transparent electrically conductive film of polyaniline with a concentration of 5, 10 and 50 % by weight on a radio-transparent fiberglass substrate were carried out. Such materials are multifunctional – the material itself has the required characteristics, but when it is exposed to external electromagnetic radiation, it provides shielding functions. Electrically conductive polymer samples (polyaniline film) deposited on a fiberglass substrate have low attenuation in the 8–12 GHz transparency band, low electromagnetic radiation reflection coefficient, high conductivity and performance characteristics, as well as manufacturability.

The paper presents the results of a study of the structure, phase composition, and growth kinetics of silicon carbide epitaxial layers on silicon substrates during their rapid vacuum thermal treatment. Transmission electron microscopy revealed the formation of layers of the cubic polytype SiC (3C-SiC) on silicon during carbidization in the temperature range of 1000–1300 °C. It was found that the formation of SiC layers proceeds in two stages, characterized by different activation energies. In the lower temperature range from 1000 to 1150 °C, the activation energy of the SiC growth process is E_a = 0.67 eV, while in the temperature range from 1150 to 1300 °C, the activation energy increases by almost an order of magnitude (E_a = 6.3 eV), which indicates a change in the limiting physical process. It has been established that the type of conductivity and the orientation of the substrate affect the thickness of the formed SiC layers. In this case, the greatest thickness of silicon carbide layers is achieved on silicon substrates with (111) orientation of p-type conductivity.

The formation processes of coatings of Cu–Ni and Ag–Cu systems with a stable elemental composition by the method of electron-beam evaporation are considered. It is shown that in the zone of action of the electron beam on the ingot placed in the crucible at the total vapor pressure of the alloy elements Σp above the pressure under the cap of the installation, the melt boils, and in the outer zone adjacent to the melt zone, the process of sublimation of the hard alloy occurs. The microrelief and elemental composition of the surface layer of the Cu–Ni alloy ingot in the zones of evaporation and sublimation, as well as the elemental composition of the coatings deposited in this case, have been studied. It is shown that the most acceptable way to obtain coatings of the Cu–Ni system with a stable elemental composition is the simultaneous electron-beam evaporation of copper and nickel from two crucibles. The azeotropic composition of the alloy of the Ag–Cu system was calculated and experimentally verified. The research results are used in the manufacture of multilayered screens of electromagnetic radiation.

Solid-state recrystallization of the surface silicon layer after chemical and mechanical polishing with application of fast thermal treatment by pulses of one second duration is one of the feasible methods of improving the silicon surface properties. The purpose of this work is to explore the impact of fast thermal treatment resulting in solid state recrystallization of mechanically disrupted layer on generation of fixed charge in SiO₂ at thermal oxidation of silicon. The results of studying P-doped electron silicon (KEF 4.5) and B-doped hole silicon (BDS 12) hole-type silicon of orientation <100> diameter 100 mm after chemical and mechanical polishing are provided. By the method of voltage-capacitance characteristic the flat zones voltage and charge density on the boundary of “silicon – silicon dioxide” were determined and by the method of scanning probe electrometry the surface distribution of these characteristic prior and after fast thermal treatment was determined. It has been ascertained that fast thermal treatment on silicon wafers KEF 4.5 and BDS 12 of orientation <100> due to solid state recrystallization of mechanically disrupted layer shall bring about 1.5 times decrease in surface potential along wafers area and residual fixed charge in silicon dioxide.

A developed technological reactor for the formation of a diamond-like carbon coating on substrates up to 200 mm in diameter by chemical vapor deposition in high-density inductively coupled plasma at an operating pressure below 5 Pa is described. The results of experimental studies on obtaining a diamond-like carbon coating in the developed reactor are presented. The dependences of the rate of deposition of a diamond-like carbon coating on the power of the RF discharge, the operating pressure, and the consumption of the film-forming gaseous reagent have been established. Also, for the developed technological reactor, the modes for obtaining diamond-like carbon coatings with the best mechanical properties were established with the following process parameters: RF power 600–900 W, precursor gas flow rate 15–50 cm³/min, the ratio of plasma-forming gas volumes to film-forming gas volume 3:1 at a residual pressure in the working chamber of not more than 4 Pa. It has been shown by Raman spectroscopy that the coatings obtained under efficient conditions contain a significant amount of a diamond-like phase.

This paper provides the simulation of laser processing of diamonds by using a combination of artificial neural networks and the finite element method. The training data array and the data array for testing neural networks were generated in ANSYS. The calculations were performed for 600 types of input parameters, 60 of which were used to test artificial neural networks. The influence of the parameters of neural network models on the accuracy of determining temperatures in the laser processing area were studied. The parameters of neural networks were established that provide acceptable results in predicting temperatures generated by laser radiation in diamonds. The results obtained can be used to determine the technological parameters of the laser processing of diamonds.

To meet the existing needs of the domestic market of radio electronic equipment in high-speed wideband operational amplifiers, it was previously proposed to use the MH2XA031 master slice array containing complementary bipolar transistors, together with the developed circuits of the OAmp9 high-speed operational amplifier and the OAmp10 precision operational amplifier with unified cascades and the ability to program parameters such as current consumption, maximum output current, bandwidth, slew rate. The article discusses the increase in the performance of these operational amplifiers by reducing the parasitic collector capacitance of transistors by applying a reverse bias voltage to OAmp9 and using correction circuits in OAmp10, which made it possible to increase the output voltage slew rate by 29 % in the first case and 3.1 times in the second. The electrical circuits and the results of circuit simulation of the upgraded amplifiers, called OAmp9M, OAmp10M, are presented, which are respectively characterized by a zero offset voltage of 0.35 and 0.03 mV, a voltage gain of 2.7 · 10³ and 3 · 10⁵, the gain bandwidth product 161 and 68 MHz, output voltage slew rate 708 and 64.5 V/µs.

The results of a study on the removal of thermal energy from processors using air coolers (AC) are presented. Four experiments were carried out, in which, with the help of three-dimensional solid-state parametric modeling of various versions of the AC, the most effective ones were identified. In the first experiment, a tower radiator with a supporting structure in the form of copper bars and a vertically mounted fan was developed, which made it possible to determine the efficiency of heat transfer through the radiator. In the next experiment, in the previously developed model, copper bars were replaced with heat pipes and the fan was removed, which made it possible to substantiate the need for the presence or absence of airflow with a gradual increase in processor power during its operation. In the third case, the possibility of changing the fan speed was implemented, which made it possible to set the maximum air flow rate for efficient cooling of the radiator. In the last experiment, the optimal design of the AC was established, which made it possible to effectively implement the dissipation of thermal energy from the processor at various power levels. The necessity of using AC in such modern technical means as personal computers, servers, computer systems, etc., in which there are no restrictions on providing weight and size parameters has been experimentally proved.

Vibration isolators with damping properties of steel multiwire cables for vibration protection of quartz oscillators have been studied. Modeling of vibration characteristics of structural elements was carried out using numerical methods. The elastic characteristics and design parameters of the cable for the vibration isolator are calculated. A harmonic analysis was carried out with given values of mass and stiffness under the influence of external vibrations. A sample of a cable vibration isolator has been developed and manufactured. To verify the calculated results obtained, the structure of the test bench is proposed, which allows determining the values of na tural re sonant frequencies. The study of the dependence of vibration acceleration on the frequency of oscillations with a disturbing effect according to the sinusoidal and random laws with a variable frequency in the range of 10–2000 Hz was carried out. Tests of the cable vibration isolator have shown the effectiveness of vibration suppression for frequencies above 120 Hz. In the lower range of random vibrations, various resonances have a significant effect on each other. The experiments confirmed the simulation results and the effectiveness of the solution used: the difference in indicators in determining the resonant frequencies was less than 10 % with a decrease in the vibration level to a given indicator.

The results of modeling the properties of graphene modified with fluorine atoms are presented. The creation of modern semiconductor devices requires the introduction of new materials. Graphene is one of them that is of interest to researchers. The addition of fluorine, hydrogen, and other chemical elements to graphene makes it possible to create its modifications. On this basis, it is possible to develop semiconductor devices and devices with improved output characteristics. The basic characteristics of graphene modification with the use of fluorine atoms, namely, the band diagram, the dependences of the density of state (DOS parameter) of electrons and holes on the energy value, were obtained by first-principles modeling. The dependences of charge carrier mobility on temperature are determined for the iterative solution of the Boltzmann transport equation The dependences and parameters obtained for fluorinated graphene can serve as a basis for creating new heterostructural devices containing layers of modified graphene and other semiconductor materials.

The application of a conditional logical formula of three-valued calculus in the decision-making system is considered. A conditional logical formula makes it possible to determine a conditional fuzzy measure on its basis, which is associated with the following positive aspects. First, there is no need for expert evaluation of the fuzzy measure of the truth of the conclusion for fuzzy premises, which reduces the degree of subjectivity and eliminates the need to ensure the completeness of statistical data, as well as the justification of completeness. Secondly, the proposed version of calculating conditional conclusions relatively simply allows for a multi-premise case and the ability to evaluate the importance of premises based on their priorities (in classical approaches like Mamdani, premises do not differ in their degree of importance for conclusions). Thirdly, there is no needto eva luate the degree of truth of the rules themselves for fuzzy conclusions. These advantages simplify practical use and ultimately improve the quality of decisions made, especially in the case of a large number of inputs (for exam ple, numbered in tens). An example of the practical use of the approach developed on the basis of a fuzzy conditional measure for making decisions about the correction of the learning process based on the testing results is given.

The features of the construction and application of graph models for solving applied problems are considered. A graph model with two quality criteria is proposed, on which the search for optimal paths between given graph vertices is performed. Each edge of the graph has a weighting factor that determines the number of time unitsrequired to pass this edge. Each vertex can be in one of two states: “open” or “locked”. Initially, all vertices are open, but their states may change in the process of problem solving. The search for a solution is limited by a given time. If during the movement along the chosen route the graph vertices become blocked, it is necessary to look for alternative ways to achieve the goal. A method for constructing a Pareto set from which admissible paths are selected is proposed. The notion of an admissible path on a graph is defined. A procedure for choosing a path from the Pareto set has been developed. Upon completion of the choice, the path is considered optimal for follo wing it from the initial vertex to the target. Situations that can occur in the process of choosing a path and passing along it are presented. Based on the selection procedure, an algorithm for finding optimal paths bet ween given vertices on a graph model has been developed.

The purpose of the article is to develop a mathematical model of VPN in communication networks of special purpose, which allows to determine the margin of throughput, for scheduled VPN-tunnels. In contrast to the well-known approaches to estimating the bandwidth margin (hose model of VPN), the developed model takes into account the class of transmitted traffic. The developed model is adequate with an accuracy of 0.95. The materials presented in the article are original and can be used when planning VPN-tunnels in a special purpose telecommunication network.

One of the modern directions of obtaining information for making informed decisions is the analysis of data from open Internet sources, the analysis of media containing hundreds of thousands of publications. It is critically important not only to obtain reliable information, but also the time needed to obtain and analyze it. The purpose of the research in this work is the development and testing of a complex methodology for quickly building a prototype of a system for complex analysis of thematic sites. A technology of interconnected methods, methodologies, and tools for building a graph database, a knowledge graph, data analysis using methods and mo dels of machine learning with the provision of analytical results to users has been created. The main task of this work is to use these technologies to analyze data from well-known world sites in order to build a prototype of a systems for complex analysis of data from Internet sources.

The task of detecting vocal abnormalities is characterized by a small amount of available data for training, as a consequence of which classification systems that use low-dimensional data are the most relevant. We propose to use LASSO (least absolute shrinkage and selection operator) and BSS (backward stepwise selection) methods together to select the most significant features for the detection of vocal pathologies, in particular amyotrophic lateral sclerosis. Features based on fine-frequency cepstral coefficients, traditionally used in speech signal processing, and features based on discrete estimation of the autoregressive spectrum envelope are used. Spectral features based on the autoregressive process envelope spectrum are extracted using the generative method, which involves calculating a discrete Fourier transform of the report sequence generated using the autoregressive model of the input voice signal. The sequence is generated by the autoregressive model so as to account for the periodic nature of the Fourier transform. This improves the accuracy of the spectrum estimation and reduces the spectral leakage effect. Using LASSO in conjunction with BSS allowed us to improve the classification efficiency using a smaller number of features as compared to using the LASSO method alone.

Analysis of studies in the field of targeted delivery of drugs, genes and stem cells showed a low level of accuracy of both applied and practical research in this area. Sufficiently encouraging results were obtained with extracorporeal electromagnetic action on a pharmacological complex with a ferromagnetic nanoparticle. With this approach, it is rather difficult to implement the algorithm for introducing the drug into the topographic region (target organ), since in practice, approaches to the clinical application of drug transport technology, taking into account the physicochemical properties of human body tissues, have not been studied in detail. The available models represent various physical and mathematical approaches that do not take into account the bioelectrical and electrostatic properties of the tissues of the organisms of experimental animals and humans. The creation of algorithms and software simulation of this technology will allow calculating variable frequency variables for magnetotargeting in a human digital phantom, which will reduce time spent at the stage of pilot and clinical trials and in the future will form the applied part of the innovative technology. The article presents the methodology and results of multiphysics and mathematical modeling in the Sim4Life for Science, V7.0 package on the example of calculating the control parameters of the electromagnetic field of the region in the area of normal administration of drugs – the vessels of the forearm.