Статьи журнала - Siberian Aerospace Journal
Все статьи: 387
Equilibrium distribution of defects in cadmium telluride before exposure to external factors
Статья научная
The reliability of electronic equipment, including in the aerospace industry, both under normal and extreme conditions, is associated with the degradation of materials due to the formation and development of a defective network. Cadmium telluride is one of the semiconductors that is actively used in the creation of solar cells and modern microelectronic devices. In this paper, the model of the point defects distribution in cadmium telluride before exposure to any ionizing radiation is proposed, that made it possible to calculate the effective thermal activation energy of a Frenkel pair equal to 1.37 eV. Studies of the features of the defects formation and evolution using modeling methods in cadmium telluride, in the future, will improve the quality of its technological use, saving financial resources and increasing the reliability of products.
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Erosion coefficient in electric contact processing of metals
Статья научная
In the production of rocket and space technology, difficult-to-machine steels and alloys are used by traditional methods. Therefore, electrical methods for processing parts are used that use a variety of thermal effects of an electric current directly in the process of removing a layer of material. In the technology of dimensional electrical processing, the role of electroerosive methods is increasing, which are increasingly used in all branches of mechanical engineering as the most effective, and often, and as the only possible ways of processing parts made of modern high-strength and viscous structural materials. One of the most promising methods of electrical processing of metal blanks is electrocontact. Performance is applied to evaluate the effectiveness of this method. The carried out literary analysis showed that the product of the current strength and the coefficient taking into account the processing mode and the material of the electrodes is used to assess the productivity. Later, this coefficient was called the coefficient of electrical erosion. For metals used in switching equipment, the value of the coefficient is given. However, it cannot be used to calculate the performance of electrical contact processing due to the significant difference in erosion processes occurring in the interelectrode gap. According to the literature data, the erosion coefficient was calculated during electrical contact processing, the results are presented in the table. In several works it is indicated that the erosion coefficient depends on the polarity of the inclusion of the rotating disk electrodes and the workpiece being processed. The data presented are contradictory; therefore, studies were carried out on the influence of the inclusion polarity on the erosion coefficient. With the same grade of the processed material and the rotating disc, the polarity of the inclusion does not matter. It was revealed that for steel grade St.3 the erosion coefficient depends on the voltage on the electrodes and, when approaching the arcing voltage, increases sharply, regardless of the polarity of the inclusion. For stainless steel, a sharp increase in the erosion coefficient is observed only at the straight polarity of the inclusion.
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Статья научная
Technological indicators of electrocontact processing of metals with a vibrating electrode-tool in an electrolyte have been studied quite fully. Knowledge of the erosion coefficient of this processing method will allow us to evaluate the performance of electrocontact processing in advance, at the stage of technological preparation of production. The article presents the methodology of the experiment, describes the installation based on a linear electrodynamic motor, which allows you to create a vibration of the electrode-tool and electrolyte flow in the interelectrode gap. The results of experimental studies are shown in the form of a graph of the dependence of the metal erosion coefficient on the water velocity in the interelectrode gap at various current densities. Based on the results and previous studies, it was assumed that the erosion coefficient depends in direct proportion on the voltage in the interelectrode gap and is inversely proportional to the volumetric heat capacity of the metal and its melting temperature. Based on the theory of electrical contacts and taking into account the features of electrocontact processing in the electrolyte, the definition of voltage in the contact zone has been refined. The theoretical value of the erosion coefficient exceeds the experimental value by two or more times.
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Errors reduction while locating objects of the radio navigation system
Статья научная
The present research considers a method for improving the accuracy of the dead reckoning position of a board station based on signals from the ground-based radio navigation systems. In the radio navigation sys-tem, grounded on the signal emitted by the base fixed stations, the slave fixed stations receive signals deter-mining the moments of their arrival relative to their own time scales. On the other hand, based on the radio frequency emitting signals by the slave fixed stations, the base fixed stations receive signals defining the moments of their arrival relative to their own time scale. According to the measured moments of radio emit-ted signal arrival, time corrections are calculated to the time scales of the slave fixed stations relative to the base fixed station. Since the time correction is calculated for a time of no more than 10 seconds, a random components are excluded due to the variability of the propagation velocity of the surface electromagnetic wave due to the variability of the environmental parameters and the parameters of the near-surface layer of the electromagnetic wave propagation area. If the calculated value of the time correction of the duration of the clock interval of the generated signal is exceeded, the moment correction (up to a clock) of the formation of the modulating code of the signal emitted by the slave fixed station is performed and the calculated value of the time correction is improved by the value of the previously corrected clock duration. The corrected values of the time corrections (pre-coded) are transmitted to each of the slave fixed stations as a part of their navigation signals. The navigation information consumer receives the radio navigation signals emitted by the fixed stations, through decoding, a consumer highlights information about the mismatch of time scales from the signals of the fixed stations and measures the radio navigation parameters with heightened accura-cy due to compensation for the error of the out-of-sync radiation signals of the slave fixed stations of the radio navigation system.
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Estimation of measurement errors of navigation and landing parameters using pseudosatellites
Статья научная
At the moment, a significant number of regional airfields do not have sufficient space for ground navigation equipment, this can lead to undesirable consequences when landing an aircraft with a weak visual contact of the crew with the runwaу. The pseudo-satellite system is able to improve flight safety at the landing stage in difficult meteorological conditions at regional airfields without using ILS (indicator on the windshield), after evaluating errors in navigation and landing parameters. The pseudo-satellite system can be used to improve flight safety at the landing stage in difficult meteorological conditions at regional airfields. This system consists of a control and correction station and pseudo satellites that operate in certain frequency ranges. When using this system, the PNP-72 scheduled navigation device is installed on the aircraft, which provides basic navigation information with a given accuracy. This allows pilots to use more accurate information and perform a safe approach and landing of the aircraft on the runway, even with weak visual contact with it. Thus, the use of a pseudo-satellite system at regional airfields can significantly improve flight safety at the landing stage, especially in difficult meteorological conditions when the use of ILS is impossible. The use of a pseudo-satellite system can also help solve the problem of an insufficient number of ground navigation aids at regional airfields. This will allow for a more accurate determination of the aircraft's location and improve the quality of navigation information provided to the crew. The use of pseudo-satellites could be an alternative to expensive and complex ILS systems, especially at small airfields where the installation of such systems may be impractical or not economically viable. However, for the successful implementation and operation of the pseudo-satellite system, additional research and testing is necessary to determine the optimal parameters of the system, as well as to develop appropriate regulatory documents and procedures to ensure flight safety.
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Статья научная
A lot of sets of subjects and objects in biology, industry, management can be divided into a number of classes, each of which corresponds to a certain distribution component. When analyzing a mixture of distributions, it is necessary to estimate its parameters (task 1) and to assess the correspondence of empirical and theoretical distribution functions (task 2). To solve the first problem, numerical algorithms that implement the method of moments and the maximum likelihood method are used. In this paper, the problem of estimating the distribution parameters is solved by minimizing the goodness measure by the Quasi-Newton method. The second problem is solved by comparing the empirical and theoretical distribution functions by one or several statistical goodness measures. Statistics of the distribution of these measures depends on the sample size, the method of forming data and estimating distribution parameters. The paper examines the goodness measure between Frocini and omega-square (Kramer – Mises – Smirnov). The evaluation of the statistics of the goodness measure was carried out by the simulation method based on the results of 50000 statistical tests. In each of the tests, the distribution parameters were estimated by minimizing the calculated value of the corresponding goodness measure. The results of simulation modeling allow estimating the statistics of the parameters of a mixture of distributions. The results of solving the considered problems for a mixture of two normal distributions of size 240 are presented.
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Статья научная
Transport operations that ensure the change of the orbit of a spacecraft or its transfer to the departure trajectory are an integral part of almost all space missions. Increasing requirements for the efficiency of transporting spacecraft form the need to search for possible ways to increase this efficiency and assess the characteristics associated with the proposed methods. Current boosters and interorbital tugs, as a rule, use a chemically powered cruise engine, although solutions with the use of an electric jet engine are becoming more common. Due to the high rate of the outflow of working fluid which is much higher than that of combustion products in a chemical engine, the efficiency of use of the substance mass by an electric jet engine significantly exceeds this indicator for a chemical engine. However, the low thrust provided by the electric jet engine leads to high duration of the transport operation and, as a result, to considerable time of exposure to the outer space factors, in particular, radiation. Therefore, the use of the electric jet engine only does not always meet the requirements for the mission. One of the promising ways to increase the efficiency of transport operations is the combination of the traditional chemical and electric jet engines in the propulsion system. Various aspects of the use of such an integrated propulsion system (IPS) consisting of a solar electric jet system and “Fregat” booster were considered, for example, in the framework of “Dvina TM” research project. Unlike a chemical engine, in which energy is released from chemical bonds, the energy for accelerating the working fluid by an electric jet engine is supplied from outside. Solar batteries are the most widespread energy source in nearearth orbits, where the amount of solar radiation is sufficient to meet the energy needs of a spacecraft. Solar batteries are sensitive to radiation, damage accumulates in their internal structure and their characteristics degrade. Therefore, there is a need to account for the radiation dose accumulated during the execution of the transport operation and to evaluate the reduction in the efficiency of solar batteries. Uneven irradiation intensity in the radiation belts formed by the Earth’s magnetic field (Van Allen belts) can be taken into account if the assessment of the radiation intensity at the trajectory points of the maneuver is made using the Earth radiation belt model. The paper proposes a method that allows taking into account the effect of ionizing radiation on the degradation of solar batteries when performing a transport operation using an integrated propulsion system based on a liquidpropellant rocket engine and an electric jet engine, taking into account the chosen trajectory and the model of the Earth’s radiation belt.
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Estimation of the number of aperiodic words
Статья научная
In 1902 W. Burnside raised the issue of local finiteness of groups, all elements of which are of finite order. The first negative answer was obtained in 1968 in the article by by P.S. Novikov and S.I. Adian. Finiteness of the free Burnside group of period n was established for n = 2, n = 3 (W. Burnside), n = 4 (W. Burnside, I. N. Sanov), n = 6 (M. Hall). The proof of infinity of this group for odd n ≥ 4381 was given in the article by P. S. Novikov and S. I. Adian (1967); for odd n ≥ 665 in the monograph by S. I. Adian (1975). In relation with these results we consider the set of m-aperiodic words. Word is called l-aperiodic if there are no non-empty subwords of the form Yl in it. In the monograph by S. I. Adian (1975) the proof of S. E. Arshon (1937) of the fact that in the two-letters alphabet there is an infinite set of arbitrarily long 3-aperiodic words was shown. In the A.Yu. Olshansky’s monograph (1989) the theorem on the infinity of the set of 6-aperiodic words was proved, and a lower bound function for the number of words of a given length was obtained. Our aim is to get an estimate for the function ()fn of the number of m-aperiodic words of the length n in the two-letters alphabet. The results can be applied when encoding information in space communications.
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Статья научная
The article discusses the prospects of utilization of aerodynamic control to maintain the formation of nanosatellites of the CubeSat class. The purpose of this work is to estimate the limits of the application of active aerodynamic control to stabilize the relative motion of two CubeSat 3U satellites in a sunsynchronous orbit with a height of 570 km. A review of theoretical information about aerodynamic forces acting on artificial Earth satellites is carried out, within the framework of which models of the Earth's upper atmosphere are considered. Aspects of creating a differential drag force for nanosatellites as an active control actuating mechanism are considered. To study the orbital motion of satellites under the action of aerodynamic control using the General Mission Analysis Tool program, a group flight of two spacecraft was simulated taking into account the factors causing orbital disturbances. Based on the results of experiments, the dynamics of the inter-satellite distance was studied, and a conclusion was made about the possibility of using an aerodynamic differential force to achieve a stable relative motion.
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Статья научная
The prospects for the development of space technology are currently closely connected with the creation of fundamentally new large-sized space structures. When designing large-sized systems, the scheme of which allows for automatic configuration change of the structure, it is necessary to take into account shock loads. They inevitably arise when fixing the working state of the structure in orbit upon completion of the process of its opening. To ensure smooth, reliable and shock-free opening of large-sized space structures, it is proposed to use force drives with active elements made of titanium nickelide material with a shape memory effect. The proposed shape memory force actuator uses an active element in the form of a wire made of titanium nickelide material which is heated during opera-tion by passing an electric current through it. One of the main parameters for the opening drive of large-sized structures is its deformation-force characteristic. Experimental studies aimed at studying this characteristic of the active element of the actuator were carried out in the work. The study of the force-deformation characteristics was carried out under two types of loading: in one, the force changed during the test, and in the other it remained constant. It is worth noting that the amount of deformation that an active element can produce is directly related to the magnitude and nature of the resistance force applied to it. In the experiment, the active element demonstrated sufficient displacement under significant load. The experimental data obtained show the fundamental possibility of using active elements made of a material with a shape memory effect in the opening drives of large-sized space structures. The obtained characteristic will play an important role in the development of a mathematical model of the functioning of an active element made of a material with a shape memory effect for the opening of a space structure with transformable configuration.
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Evaluation of the main parameters of ReshUCube-1 telemetry over a period of 10 months in orbit
Статья научная
With the increase in the number of launched spacecraft, such a direction as automation of spacecraft control processes is gaining popularity. One of these most important processes is the analysis of telemetry data during the operation of a spacecraft. Scientific and educational satellite of the Reshetnev Siberian State University of Science and Technology has been successfully exploitated in orbit and has been performing its scientific tasks for more than six months. The article considers a list of the main parameters analyzed by the operators of the Mission Control Center to assess the state of the ReshUCube-1 satellite. The composition and main functional characteristics of the equipment on the spacecraft are described. Qualitative indicators and quantitative limits for all described parameters are given, as well as their significance and impact on the functioning of devices and the entire spacecraft as a whole.
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Evolution of heuristics for selection synthesis in a genetic algorithm
Статья научная
A method for the automatic design of selection operators for a genetic algorithm is proposed, based on the Evolution of Heuristics (EoH) approach, which integrates the capabilities of Large Language Models (LLMs) and evolutionary search. The design of selection operators was carried out on three pseudo-Boolean optimization problems, and testing was performed on 17 functions from the IOHprofiler benchmark set. Two experimental setups were considered with and without explicit knowledge of the type of problem being solved. The language model used was DeepSeek-Coder-V2, which was deployed locally using the Ollama framework. The quality of the designed heuristics was determined based on the comparison with the results of standard rank selection. The quality of the obtained solutions is compared with classical selection schemes (tournament, proportional, and rank-based), as well as with the FunSearch method, previously used to generate new implementations of rank-based selection. A comparison of various heuristics was carried out for multiple runs on each of the 17 tasks using the nonparametric Mann-Whitney statistical test. It has been shown that automatically designed heuristics have unique properties, and the lack of information about the type and structure of the problem being solved has led to a greater variety of generated solutions. Namely, in one of the launches, without information about the type of task, the designed code selects individuals whose fitness differs from the maximum by less than half the distance from the maximum fitness to the median. In other words, it is a variant of tournament selection with an adaptive tournament size based on the distribution of quality. The availability of information about the type of problem being solved led to the fact that the language model generated typical known solutions, in particular, variants of simple tournament selection. The proposed approach can be applied to other tasks of automatic design of algorithms as a whole or components of algorithms.
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Evolutionary algorithm with an autoencoder-based dimensionality reduction mechanism
Статья научная
Many modern applied optimization problems are formulated as black-box models, characterized by a lack of analytical information about the objective function and its properties. While Evolutionary Algorithms (EAs) are frequently applied here, their performance degrades in high-dimensional spaces with complex landscapes. Moreover, these algorithms require generating a large number of trial solutions for effective operation, which may be unattainable in applications with expensive objective function evaluation. To overcome these limitations, we introduce a novel EA framework centered on adaptive, autoencoder-based dimensionality reduction. The autoencoder is retrained dynamically during the search using evolving population data. The strategy relies on the parallel operation of two optimization algorithms: one works in the original solution space, and another operates in a latent space – a compact, nonlinear representation of the current population generated by the autoencoder. This design enables the algorithm to adapt to the problem's specific structure. We evaluated the method on standard benchmark problems, analyzing its convergence dynamics and sensitivity to the latent space size. Statistical significance of the results was assessed using the Wilcoxon rank-sum test. The L-SRTDE algorithm was used as the subpopulation optimization method. Numerical experiments demonstrate that the proposed algorithm enhances search space exploration in first optimization stages but, on average, is slightly less efficient than the base algorithm.
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Статья научная
The development of new ballistic-type aircraft is characterized primarily by improved aerodynamic characteristics and higher speed limits. Ground track testing of aviation and rocket technology is a stage whose task is to confirm the efficiency and effectiveness of new developments. Track tests make it possible to simulate real loads, they are simpler and much cheaper than flight tests. Experimental installation "Rocket rail track 3500" of Scientific Test Range of Aviation Systems named after L. K. Safronov is constantly being upgraded in order to conduct track tests of products at a speed greater than 3M. The experimental setup includes a two-rail track, made on a special foundation, which excludes unacceptable rail deflection with a mass of up to 3000 kg. The rail track has an acceleration section with an angle of attack 2500 m long and a deceleration section. A tray filled with water is made on the braking section between the track rails. It is designed for hydrodynamic braking to a complete stop of the rocket sled with stored equipment. The movable rocket track sled is made of a massive steel plate to which three cross beams are welded. The front and rear beams end with axles on which sliding supports are pivotally mounted. On the rear and middle beams there are lodgements for fastening rocket engines of solid fuel. Depending on the required test speed, from one to five motors can be placed on the cradles. The test object is usually mounted on the front and middle beams along the axis of the sled and fixed in a cantilever, with the head part extended forward. The design of the supports – shoes is made to encircle the rail head in such a way that it provides sliding contact along the upper plane of the rail head, and in the event of a lifting force exceeding the weight of the sled at high speeds, it keeps the structure from free flight by contacting the lower surface of the rail head. Track high-speed tests of special equipment objects are always accompanied by intense vibration and shock effects of structural elements. Due to the desire to conduct track testing of products at a faster rate, it becomes necessary to reduce the level of dynamic loads and eliminate resonant interactions. The article presents an algorithm and methodology for statistical processing of random signals of three-axis vibration acceleration sensors installed on the shoes of the rocket track sled and on the fairing of the test object. Due to the placement of registration data storage devices on the sled, experimental vibration data were stored when testing the product at a speed of more than 1M. The autocorrelation functions of the signals of vibration accelerations of sensors placed on various elements of the rocket sled, the functions of mutual correlation of the corresponding signals, the density of the amplitude spectra, the density of the power spectra and the transfer functions that characterize the dynamic conductivity of vibrations from the shoes sliding along the rail guides to the test object were determined.
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Статья научная
Electro-jet (plasma or ion) thrusters are becoming increasingly common to correct a satellite orbit and perform orbit raising maneuvers to achieve the geostationary orbit. This is due to the greater efficiency of plasma thrusters compared to chemical ones. When developing a satellite platform, an important place is the matching up of the electrical character-istics of the electric power subsystem (EPS) and on-board consumers. Intrinsically, this issue is an intersys-tem problem. The lack of proper attention paid to find the timely and correct solution of this problem can complicate the operation of the satellite electric power subsystem. The most important subsystem, which has a significant impact on the operation of the satellite EPS, is the electric-jet propulsion subsystem, since among on-board consumers, this one is the most powerful consumer being switched simultaneously. Tran-sients occurred in the power supply circuits following thruster firing and shut down processes can reach significant values. An electric jet thruster only runs in conjunction with a complex electronic unit – a power processing unit (PPU), which converts the voltage of the on-board power supply into a set of voltages nec-essary for thruster components to run. Therefore, in the preliminary design of the propulsion subsystem, it is necessary to know the electrical characteristics of transients and ripples in the power supply circuits of the thruster / PPU combination being an electrical load of the Electric power subsystem. It is difficult to obtain the characteristics of such processes by the calculation method. Therefore, an experimental method is the most common and objective method to obtain this information. JSC ISS carried out tests allowing to measure characteristics of transients and ripples under firing, running and shut down of plasma thrusters of different types powered by corresponding PPU’s. These tests were conducted using a vacuum chamber GVU-60. A test power supply was used to simulate EPS operation. This paper presents the results of meas-urements and analysis of parameters of transients and ripples on PPU power buses used for thrusters and devices of three types. These results are considered to be preliminary. It is shown that the greatest difficul-ties can arise when operating high-power thrusters. It is concluded that for each new type of thrusters and PPU’s it is advisable to conduct interface tests of the propulsion subsystem and the satellite electric power subsystem.
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Статья научная
Increasing the efficiency of liquid rocket engines (LRE) is inextricably linked to the intensification of cooling processes in heat-critical elements such as combustion chambers and nozzles. Additive Manufacturing (AM) technologies, in particular selective laser fusion (SLM), make it possible to create cooling paths with complex internal channels and heat transfer intensifiers. However, the surface microrelief formed in this case has a significant effect on hydrodynamic resistance and heat transfer, which is not always taken into account in existing design methods. An experimental assessment of the effect of surface roughness, characteristic of additive manufacturing, on the formation of a dynamic boundary layer under conditions simulating flows in the cooling channels of liquid propellant is considered. The sample plates made of AlSi10Mg aluminum alloy were made using the SLM method: with controlled roughness and flow intensifiers. The surface roughness profile was evaluated on a TR 110 profilometer. The research was carried out on a specially designed aerodynamic installation that simulates the flow in a rectangular channel. The velocity fields in the wall area were measured by the pneumometric method at a fixed air flow rate. The errors were estimated and the data approximated. It is established that the roughness of SLM surfaces leads to a significant restructuring of the velocity profile in the boundary layer compared to the hydraulically smooth case: a decrease in its thickness and a change in the shape of the velocity diagram are observed. The largest deviations were recorded for the plate with intensifiers. Power-law approximating dependences are obtained for each type of surface, where the exponent varies depending on the roughness parameters. It is shown that the use of boundary layer models for smooth surfaces in liquid propellant calculations in relation to additive parts can lead to incorrect estimation of hydraulic losses and, as a result, to errors in predicting the temperature state of the wall. The obtained dependences are necessary for the development of adjusted calculation methods that take into account the actual topography of the surfaces formed by AM methods, which will increase the reliability and efficiency of the design of liquid propellant cooling systems.
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Статья научная
In this paper the approach for external boundary of pole localization region formulation for transfer function with interval-given parameters is proposed. The boundary is formulated as analytic piecewise function of characteristic polynomial parameters of the given transfer function. Analytic formulation of external boundary of poles localization region allows to reduce computations since existing methods require iterative numeric calculations of characteristic equation roots with fixed step size for edges mapping or full interval root locus mapping as well. Formulated boundary allows to clearly describe system behavior and calculate variation ranges of performance indexes. In addition, piecewise function that constrains gives new opportunities for parametric controller synthesis for systems introduced by transfer functions with interval-given parameters. The results can find its practical application in aerospace engineering problems of mathematical analysis and synthesis for highly-precise systems of self-direction missiles. In the research the boundary formulation is performed for third order transfer function. Transfer function order was chosen due to the fact that many physical systems and objects can be described mathematically with the third order transfer function, e.g. model of missile target-seeking head with gyro stabilized drive is described with this model. The research was performed on the basis of the following step sequence: firstly, analytical solving of cubic equation applying Cardano’s formula; secondly, interval root locus edges functions obtaining, next external vertexes set obtaining and, finally, external border formulation and plotting.
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Factor analysis of inelastic electron scattering cross section spectra of iron monosilicide FeSi
Статья научная
The inelastic electron scattering cross-section spectra of FeSi silicide were calculated from the experimental reflected electron energy loss spectra as the product of the average inelastic mean free path and the differential cross section of the inelastic electron scattering. To inelastic electron scattering cross-section spectra study, factor analysis was used. This method allowed us to quantitatively separate the surface and bulk contributions to the spectra, and determine the energy of the bulk plasmon more accurately than it is possible using traditional methods. Inelastic electron scattering cross-section spectra (Kλ-spectra) are the products of the average inelastic mean free path λ and the differential inelastic scattering cross-section K (E0, E0 – E), where E0 and E are the energies of the primary and reflected electrons, respectively. The advantage of inelastic electron scattering cross section spectroscopy is that, unlike the reflected electron energy loss spectra, the Kλ-spectra exclude losses due to multiple excitations, and the intensities are determined in absolute units. These spectra are also more sensitive to changes in the energy of the primary electrons and the angle of emission. Inelastic electron scattering cross-section spectroscopy allows to determine the element composition with much greater accuracy than the traditional method of reflected electron energy loss spectroscopy. In this work, factor analysis is used to study the inelastic electron scattering cross section spectra of the FeSi silicide. This method allowed to solve the actual problem of separating spectra into contributions of a different origin, quantify them and determine the energies of a bulk plasmon more accurately compared with traditional methods. The study of electron energy loss processes by isolating contributions of different origin in the inelastic electron scattering cross section spectra is one of the urgent problems of electron spectroscopy, which can be used to assess the effect of surface excitations in REELS, XPS and AES.
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Статья научная
During the liquid rocket engines (LRE) testing, direct thrust measurement is carried out using thrust measurement devices. The aim of the work was, on the basis of existing data from the theory of tests and test stands devices, to highlight the design features of the thrust measurement devices and propose an option to improve the performance of this stand system. The work considers the basic circuit power schemes of thrust measurement devices by the example of power measuring systems of existing fire test stands and the features of work on preparing systems for testing. The types of calibration systems worked out in practice, their advantages and disadvantages, which constitute calibration errors, are considered. An option is proposed to modernize thrust measurement devices, in particular, through implementing of an electromechanical drive based on a planetary roller-screw mechanism as a force setting element into the calibration system. A possible general conceptual diagram of the power drive operation as a part of the calibration system of the thrust measurement devices is given. The advantages and disadvantages, the predicted effects of implementation are considered. A more detailed analysis of this proposal may serve as an occasion for the modernization of the specific operational thrust measurement devices design at the fire test stand for LREs or may be a working option when designing a new thrust measurement device.
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Features of electroactivated water production at a coaxial electrode location
Статья научная
Important characteristics of any product are quality and reliability. One of the factors affecting product reliability is the surface cleanliness provided by flushing with liquids. Electroactivated water and aqueous solutions can be used as liquids. On the basis of domestic and foreign experience, leading experts have developed methodological instructions for the widespread implementation of electro-activated water and aqueous solutions in instrument-making and mechanical engineering. For the production of electrochemically activated water and solutions, non-flowing and flowthrough modular elements, as well as universal installations, have been developed. Analysis of the structures of these devices has shown that flat metal plates are used as electrodes, therefore there are volumes of water that are subjected to uneven electrical effects. As a result, the specific energy consumption for obtaining activated water is significant. The purpose of the work is to reduce the specific energy consumption in the production of activated water and aqueous solutions. Coaxial arrangement of the electrodes leads to reduction in energy consumption. The study of the electroactivator of water with a coaxial arrangement of electrodes allowed us to establish the optimal ratio between the volumes of anolyte and catholyte and the time of electrolysis of water and an aqueous solution of sodium chloride. A new indicator of efficiency (the specific energy consumption per unit of change in the pH of water or an aqueous solution) objectively reflects the perfection of the design of electroactivators. The research results can be used in instrument and mechanical engineering.
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