Background. The specifics of manufacturing self-healing fuses based on polymer crosslinking are considered. Materials and methods. Radiation crosslinking of polymers is evaluated against the background of exposure to ionizing radiation with the formation of transverse chemical bonds between macromolecules, leading to the formation of a spatial grid. Results. Based on the research, analysis and work carried out, a block diagram of a special technological process for manufacturing self-healing fuses and its main operations was determined. Conclusions. During the production of test samples and experimental batches, special technological processes were worked out, such as: soldering of terminals to resistive boards; manufacturing of resistive boards; laser marking; control of electrical parameters.

Complex high-speed electronic systems have been relevant for research in terms of the vibration load effect thereon. Currently, printed circuit board manufacturing technologies are a well-established production mechanism to fabricate high-quality products. However, despite high reliability of electronic equipment, there is failure probability in the design of printed circuit board due to critical deformations and mechanical stresses under certain (harsh) external conditions of influencing factors. In this regard, it is urgent to consider, analyze and prevent such critical deformations in printed circuit board design. This paper considers mathematical, simulation, algorithmic, and software methods for analyzing and calculating critical deformations and mechanical stresses in standard printed circuit board design to increase its mechanical strength. The research aims to improve simulation models and design methods for electronic equipment to enhance the accuracy of reliability prediction thereof. An improved mathematical and simulation model for calculating mechanical stresses and displacements of a printed circuit board have been developed. An algorithm for applying the improved mathematical model has been proposed, and a program for calculating a specifying coefficient has been elaborated.

In the cubic nonlinear approximation, we analyze the processes of generating the electric pump field by an electron beam and its effect on the amplification of space charge waves (SCW) in the amplification section of a parametric superheterodyne free-electron laser (FEL). We found that the generated pump electric field amplitude is within 21…33% of the amplitude of the external pump electric field. We showed that the generated pump electric field is in phase with the external one. It leads to an increase in the growth increments of SCW; therefore, the length of the SCW amplification section is reduced by 22%. We found out that this field does not destroy the mode of amplification of multi-harmonic SCW. Thus, the studied effect makes it possible to create FELs with smaller longitudinal dimensions and powerful electromagnetic waves with a complex multi-harmonic spectrum.

In this work, within the framework of the quadratic nonlinear approximation, we analysed the influence of the generated pump electric field on the amplification properties of a parametric superheterodyne laser (FEL).The high amplification properties of such a device are ensured by implementing two interconnected three-wave parametric resonances.Due to the first of these resonances between the electromagnetic wave of the signal, the H-ubitron pump magnetic field and the slow space charge wave (SCW), the first one is amplified.The second of these resonances between the longitudinal pump electric field, slow and fast SCWs allows us to increase the slow SCW more.The connection between the two parametric resonances is ensured by the slow SCW common to resonances.In the work, the growth increments of the waves of the above-mentioned three-wave resonances are analysed separately and for the entire system.It has been demonstrated that generating an additional pump electric field significantly affects the growth increment of the second parametric resonance of longitudinal waves, increasing it by 33 %.Due to this, the growth increment of the entire FEL increases by 28 -10 %, depending on the system parameters.It was found that the influence of the generated pump electric field is most effective at high frequencies and relatively low energies of the electron beam when the amplification of the electromagnetic signal due to the first parametric resonance is significantly less compared to the amplification of longitudinal waves due to the second parametric resonance.

The paper considers a technique for determining the lowest natural oscillation frequency of a simply supported circular cylindrical shell. An analytical expression for the frequency parameters of a cylinder with clamped ends is obtained. Numerical solutions of test problems using the ANSYS software package are performed. Based on a comparative analysis of natural oscillation frequency for the cylinders with simply supported and clamped ends, conclusions are drawn and recommendations are given to increase the rigidity of cylindrical structures for on-board radio-electronic equipment.

Background. The rapid pace of development of electronic equipment, especially its main part of the printed circuit board, poses the urgent task of constantly creating and updating existing means and methods for detecting and diagnosing the parameters of printed circuit boards under external influencing factors. In turn, the advanced rates of development of microelectronics require a continuous increase in their technical level, which is determined by an increase in the density of installation of electrical radio products, increased requirements for reliability, and an increase in operating frequency. Meeting these requirements allows achieving a high level of design and development of technology for the production of printed circuit boards. Materials and methods. When developing a system for detecting thermophysical parameters of electronic equipment, methods of statistical data processing and measurement theory, design techniques and object-oriented programming were used. Results and conclusions. A combined method for calculating the thermophysical parameters of electronic units has been developed. The issues of mathematical modeling of temperature fields of printed circuit boards are solved. A technique for detecting critically unstable elements of electronic equipment using a four-channel thermal field measurement system has been implemented.

Background. The basis of the load-bearing structures of on-board electronic systems (OES), as well as many other engineering products, are thin-walled elements – rods, plates, shells, which should provide the necessary strength, stability and rigidity of the structure under given weight restrictions. At the same time, the choice of design margins for all performance parameters of elements of such structures (safety factors, safety margins) should ensure reliability equal to or higher than the required one, which can be achieved by creating resonance-free structures in a given vibration frequency range. The aim of the work is to develop an engineering methodology for calculating the necessary margin for detuning the natural frequency of oscillations and its practical use. Materials and methods. The paper uses the provisions of the theory of mechanical vibrations to obtain analytical expressions for the natural vibration frequency of a cylindrical shell. For the numerical solution, finite element methods and the ANSYS software package are used. Results. The results of calculations of the natural frequency of vibrations of thin-walled structures of on-board radio-electronic equipment are proposed, which make it possible to reasonably select the dimensions of the structure in terms of protection against Numerical solutions of test problems are performed using the ANSYS software package, conclusions are drawn and recommendations are given for the creation of resonance-free in a given vibration frequency range of thin-walled structures of on-board radio-electronic equipment units in the form of circular barrels. Conclusion. The results of the work are presented in the form of recommendations for determining the main natural vibration frequencies of casings in the form of circular barrels and choosing design solutions for creating non-resonant structures at the early stages of designing.

Background. According to electronics failure analysis, 90 % of failures occur in a very limited number of failed component types. Possible causes of failures of these types of components are easy to analyze. The paper considers the least statistically reliable elements – power transistors and electrolytic capacitors. The analysis of influencing factors is carried out and a technique is proposed aimed at determining the operable state of the device. Materials and methods. To solve the tasks set, methods of system analysis, reliability theory, and materials science are used. Results. The article discusses modern approaches to monitoring the performance of a device by indirect parameters of electronic devices. The shortcomings of the approaches used are noted. An analysis of the impact of factors on the service life of the device was carried out, on the basis of which a methodology was developed for assessing the control of the device's performance by indirect parameters related to power transistors and electrolytic capacitors for the electronic unit based on a mathematical model that takes into account operating conditions. Conclusions. Based on the proposed methodology, it is advisable to create a system for registering external influences, which allows real-time monitoring of operating conditions and, taking them into account, predicting the residual life of the electronic unit.

The article examines the issue of classification of unmanned aerial vehicles. The existing classifications of unmanned aerial vehicles are considered, as well as the characteristics by which unmanned aerial vehicles are classified. Like any aircraft, unmanned aerial vehicles can be classified by general characteristics such as type of aircraft, size, weight, engine type, degree of autonomy, application, and other characteristics. Due to dynamic development of the field of unmanned aerial vehicles, the number of their classification characteristics is increasing. Due to the rapid development of unmanned aerial vehicles, existing classifications of unmanned aerial vehicles do not consider some existing types of unmanned aerial vehicles. The main goal is to propose a classification of unmanned aerial vehicles, which takes into account great variety of modern unmanned aerial vehicles. The following characteristics were considered, according to which unmanned aerial vehicles are classified, namely - by type of aircraft, by size, by range and endurance, by degree of autonomy, by altitude, by engine type, by take-off and landing principle, by application. As a result of conducted analysis of characteristics by which unmanned aerial vehicles are classified, a classification of unmanned aerial vehicles is proposed based on their characteristics, designs and tasks they perform.

Background. The relevance of the information-measuring system (IMS) for verification of kilovoltmeters with an automated mode of operation is determined by the need to quickly verify a large volume of primary high-voltage converters and high-voltage measuring instruments (SI) used in automatic high-voltage control systems. The purpose of the work is to familiarize with the current state and the new automated IMS for checking kilovoltmeters. Materials and methods. Method of comparison with exemplary SI. Results. An overview of various verification IMS and software (SW) is given. A modern automated IMS for checking kilovoltmeters is proposed. Conclusions. The review made it possible to single out the advantage over the existing systems of the new IMS for checking kilovoltmeters, which makes it possible to work quickly with high-voltage measuring instruments.

We analysed the multiharmonic interactions of space charge waves in the amplification section of the superheterodyne free electron laser in the submillimeter wavelength range within the framework of the cubic nonlinear approximation. We use an undulator with a longitudinal periodic reverse electrostatic field to amplify longitudinal waves. We researched the effect of generating an additional periodic reverse pump electric field by an electron beam. We demonstrate that the device can amplify multiharmonic signals without distorting of their amplitude spectra. With the given input parameters of the considering FEL, we found the feasible in practice values of the saturation length and level of the amplification of a terahertz signal. Also, for the first time, we studied the effect of generating an additional electric pump field due to the electron bunching in a relativistic electron beam in a linear approximation. We show that the resulting pump electric field increases by 33% due to this effect. This leads to an increase in the growth rate of space charge waves and a decrease in the saturation length by ∼33%

Background. The rapid development and widespread use of various unmanned aerial vehicles requires the introduction of their typification and certification. The paper considers one of the possibilities for the development of a mechanical transmission unit for a device for measuring the thrust of a propeller-engine pair for further use for metrological purposes in the design of new aircraft. Materials and methods. The computer simulation method is based on the use of the Autodesk Inventor software package for calculating loads and selecting material for the future unit assembly. Results. In the course of the study, it was found that the computer simulation method for calculating the maximum allowable contact stresses of gear wheels for a given material satisfies the results of a classical mathematical model, with some errors. Conclusions. With the same results of mathematical calculations and calculations in Autodesk Inventor, the program greatly simplifies the work by automating the calculation process, especially when it is necessary to replace the original data.

VEPP-2000 electron-positron collider operating in the beam energy range of 150-1000 MeV is the only machine originally designed for and successfully exploiting Round Beams Concept. After injection chain upgrade including link to the new BINP injection complex VEPP-2000 proceeded with data taking since 2017 with luminosity limited only by beam-beam effects. At the low energies (300-600 MeV/beam) the novel technique of effective emittance controlled increase by weak coherent beam shaking allowed to suppress the limiting flip-flop effect and resulted in additional luminosity gain factor of 4. The averaged delivered luminosity at the omega-meson production energy (2×391 MeV) achieved L =2×1031 cm2s1/IP. At the top energies above nucleonantinucleon production threshold the stable operation with luminosity of L = 5×1031 cm2s1/IP resulted in high average data taking rate of 2 pb1/day in 2020.

The article discusses a method to increase the efficiency of evolutionary genetic search in coding of modular network structures. A method for unfolding a genotype to form a phenotype using production rules generated by applying formal apparatus of L-systems and repair mechanisms is proposed. Forward and reverse coding techniques are considered. The method provides a combination of compactness of genetic code representation and advanced capabilities to increase dimension of resulting networks.

4 Институт биофизики клетки (ФГБУН «ИБК РАН»), Институтская, 3, г.Пущино, Московская область, 142290

In the present work, within the framework of nonlinear cubic approximation, the analysis of the possibility of controlling the parameters of a wide frequency spectrum in multiharmonic two-stream freeelectron lasers of klystron type by means of a longitudinal electric field was carried out.The quasihydrodynamic equation, the continuity equation and Maxwell equations were used as the calculation basis.Using the method of averaged characteristics, we obtained a system of differential equations describing the dynamics of wave harmonics amplitudes of a superheterodyne free-electron laser.We demonstrated that in the studied system, it was possible to realize plural three-wave parametric resonances between space charge wave harmonics.In this case, simultaneous three-wave resonant interaction between a number of triple harmonics of the space charge wave occurred.Such three-wave resonances were also interconnected through certain common harmonics.It was shown that the conditions of plural three-wave parametric resonances between space charge wave harmonics, which are amplified due to two-stream instability, persisted in a two-stream electron beam despite the change in the velocity of the two-stream electron beam under the influence of the longitudinal electric field.It was found that the longitudinal accelerating electric field led to a significant increase in the frequency spectrum width of the multiharmonic space charge wave.The decelerating electric field reduced the width of the frequency spectrum of this wave, but the level of harmonic saturation increased.We proposed to use the accelerating electric field in the transit section of the multiharmonic two-stream superheterodyne free-electron laser to generate powerful multiharmonic electromagnetic signals with a wide frequency spectrum, including ultrashort clusters.

A significant problem in the dairy farming industry is the decrease in the livestock reproductive capacity due to the ovaries physiological functions violation. This study examines the lipids, proteins and carbohydrates metabolism state, depending on the sexual cyclicity recovery in animals degree, while observing adequate feeding. For the experiment, 16 new-calving Holstein-Friesian cows with an average annual milk yield of 9.5 thousand kg were selected, divided into 2 equal groups, depending on the ovulatory function resumption. All animals received a balanced diet. Blood was taken on days 6, 12, 19, 40 and 68 after calving. Blood serum was separated and the total protein and individual fractions content, as well as the creatinine, urea, total lipids, cholesterol, triglycerides, glucose amount, were determined. To determine the hormonal status, the content of estradiol and progesterone was examined. The reproductive organs condition was assessed using transrectal palpation and using an ultrasound apparatus. We found that cows with ovarian dysfunction are characterized by protein and glucose globulin fraction decreased concentrations in the blood, increased creatinine content and hypothalamus-pituitary-gonad system hormone-producing function inhibition. With an accuracy of 87.5%, the glucose threshold level in the blood serum was revealed, at which ovarian dysfunction can be predicted: a decrease in fertility in cows is observed at a rate of <2.2 mmol/l. Taking into account the previous studies results, further research expediency on finding the hormonal and metabolic status relationship with ethology typological features and the central nervous system state is substantiated.

Within the cubic nonlinear approximation framework we performed the analysis of space charge waves (SCWs) with broad frequency spectrum amplification in superheterodyne free electron laser (FEL) with longitudinal electrostatic undulator. We found out that the system under study allows realization of plural resonances of two types. We showed that in such FEL the SCW growth rates do not depend on the frequencies of the amplified waves. The lengths at which the SCW with broad frequency spectrum amplification occurs without distorting its shape are determined.

Based on the properties of Huygens elements, a solution for determining the electric component strength of the electromagnetic field, taking into account the influence of a reflective surface of a complex shape, is proposed. The paper uses the application of geometrical optics method for the case when the length of the electromagnetic wave is comparable with dimensions of its reflection surface. To represent the complex shape of the reflective surface of objects, the decomposition method is used, where each section of the partition has the properties of the elementary Hertzian electric dipoles. The calculated expressions for the main planes of the Cartesian coordinate system are obtained, allowing us to determine the strength of the electric component of the electromagnetic field as a result of reflection, taking into account the amplitudes and phases from each elementary surface section of the complex shape. The developed method allows determining the strength of the electric component of the electromagnetic field as a result of reflection, taking into account amplitudes and phases from each elementary surface section of the complex shape, correctly divided into rectangular surfaces of reflection with optimally chosen dimensions. In addition, the directional properties of the reflective surface are functionally described, being an advantage in searching for effective design solutions in the process of developing radio-electronic means for various purposes.