Статьи журнала - Сибирский аэрокосмический журнал
Все статьи: 3183
Статья научная
Обобщен опыт по созданию и использованию Internet-репозитория образовательных ресурсов университета, обеспечивающий распределенный доступ к полнотекстовым аналогам учебных изданий, представлен обзор сайтов образовательных ресурсов высших учебных заведений Дальнего Востока и Сибири.
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Invariant method of information transmission in fiber-optic transmission systems
Статья научная
We have synthesized a method of controlling the distortions introduced by fiber-optic communication lines. This method is based on the use of invariant equality. Its main technical characteristics have been determined.
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Invariant signaling with processing in the frequency area
Статья научная
A method of sending signals to the subsequent processing in the frequency domain is offered. To implement such a treatment, a structure is proposed based on the direct and inverse Fourier transformation with an element of division, making the division of information signals and training signals possible.
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Investigation of charge-discharge processes in the spacecraft detachable connector
Статья научная
Modern spacecraft consists of structural materials with different electro-physical characteristics, and it causes the occurrence of charge-discharge processes on the spacecraft during interaction with the magnetospheric plasma. The study of this phenomena arising during the natural spacecraft charging and its influence on the onboard systems func- tioning is of great interest in the field of ensuring the stability of spacecraft under the space factors influence. The paper presents the experimental results of charge-discharge processes occurring in detachable connectors dur- ing in-space exploitation after undocking the separating device and placing the spacecraft onto the orbital slot. For the determination of impact factors characteristics of electrostatic discharge and its potential effect on spacecraft board equipment the charge-discharge processes research methods with account of spacecraft equipment interfaces were de- signed. For modeling of electrostatic discharge in detachable connectors and its effects in technological circuits of spacecraft equipment the imitation loads were applied. These loads include input interface elements of spacecraft power convectors and onboard control complex. The results show that the dielectric material of connector contact field can accumulate a charge to the value limited by the discharge on it. Discharge processes on the dielectric material induce interfering pulses in onboard cable har- ness and can have a significant impact on the work of onboard equipment. The obtained results are useful in spacecraft equipment designing in the sphere of interference immunity.
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Статья научная
This paper is devoted to the high-effective process of surfacing by the indirect three-phase arc with covered electrodes. The share of the parent metal in the surfaced one does not exceed 10 % which is infeasible for one-arc surfacing.
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Статья научная
High-precision and reliable inspection of thermal deformations is necessary in terms of simulating the effects of space in the ground-based experimental processing of antennas and mirror systems of spacecrafts. Inspection of objects up to 1.5 m in size is considered in the paper. In practice, it can reach sizes up to 10 m. Requirements for thermal deformation are in range of 10-200 micrometers. The deformable surface is rough (Ra » λoptic). The measurement error, however, should not exceed ± 1 micron. The electronic speckle pattern interferometry (ESPI) method is the most suitable for solving this problem. The method allows to inspection objects with a randomly inhomogeneous surface. The method assumes that it is necessary to calculate the wave phase values from the recorded picture by the digital matrix. It is the phase that contains information about the deformation, and the spatial phase shift method is used to calculate it. One of the measuring systems based on this method is the measuring system PulsESPI (Carl Zeiss Optotechnik GmbH production, Germany). It has a high sensitivity which is about 50 nm. However, this measuring system is designed for single measurements. In this regard, an additional software module for processing and visualization the result of a series of several hundred measurements has been developed. The experimental test bench with a test object has been developed to research the metrological characteristics of the PulsESPI system in accordance with thermal deformations measurements (multiple determinations). The PulsESPI system and the Renishaw XL-80 interferometer introduced into register of measuring instrumentation of Russian Federation were located on different sides of the object 1.5 m in size. As a result of measuring the surface displacement measured by the Renishaw XL-80 interferometer and its corresponding point from the PulsESPI system deformation map are compared. Three types of tests were carried out at the developed bench. The root-mean-square deviation of single measurements was no more than ± 0.2 μm. Error was no more than ± 1 μm when the series of measurements was conducted in which a total strain of 200 μm was obtained. The results obtained suggest the possibility of using this system for high-precision inspection of thermal deformations of large objects.
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Статья научная
The impact of magnetic fields caused by thermoelectric currents and residual magnetization of the welded parts on the accuracy of an electron beam positioning along the welded joints is a complicated scientific and technical problem to achieve high quality of welds in the aerospace industry, shipbuilding and power engineering. Presented in the article mathematical models of distribution of magnetic fields of interference in the space between the electron beam gun and the surface of a welding workpiece and also inside a workpiece allow to culculate the quantitative characteristics of the electron beam deflection from welded joints. The authors propose to use a deflection system for compensation of mag- netic interference impact. The deflection system must be set to a certain height above the workpiece to be welded. The authors obtained a mathematical model of the magnetic field induction of the deflecting system distribution along its axis which coincides with the optical axis of the electron beam gun. The coordinates of installation of the deflection system concerning the surface of the parts to be welded are determined using the presented mathematical models. Cal- culations showed that the height of installation of deflection system depends on the thickness of the welded components. Using the deflection system installed at a certain height above the workpiece to be welded allows to eliminate the impact of magnetic fields caused by thermoelectric currents and residual magnetization of the welded parts on the quality of welded joints.
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Issues of reliability in smart antennas
Статья научная
Adaptive digital antenna arrays, also known as smart antennas, are a perspective direction in the development of ground-based command and measurement antenna stations. Smart antennas can significantly improve the efficiency of controlling data exchange between the satellite and ground-based earth station. This benefits the productivity of the technological operations and reduces the time intervals forperforming the technological control cycle. Depending on the requirements, smart antennas containfrom a hundred to several thousand active modules. In this case, the probabil- ity of failure of the active module increases. This article discusses the issues of ensuring reliability ofsmart antennas : their ability to maintainin timethe values of their technical parameters within the established limits, which are deter- mined by failures of the equipment included in the antenna, mainly by module failures.
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Laboratory separator of bulk materials
Статья научная
New materials for spacecraft radiation screens engineering require a fine classification of powder materials by particle size. The article concerns the construction of powder materials laboratory separator. This type of material separation is related to gravity methods. The Moseley laboratory separator serves as the prototype of the construction with table longitudinal shaking and diametrical vibrations by means of buffers during the separation process. The unbalanced oscillator yields deck separation surface harmonic vibrations in all directions. The unbalanced oscillator DC motor voltage control gradually alters the vibration frequency and supports finer separation of the material. A power pipe enables to conduct perpetual separation process. In prototype, in contrast, up to 100 g weight is processed for up to 5 minutes. To improve the materials fine and small classes separation efficiency, riffles are made on the separation surface, which determine the places of concentration of material particles. As a result of the conducted researches for elimination of the secondary circulation flows, a system of diametrical reefing is worked out: the riffle is approximately equal to the maximum particle size of the separated material and is equal to 0.2 mm in this construction; the distance between riffles is equal to 50 mm, the tilt angle is 80 degrees relative to the deck longitudinal side. The particle motion depends on the inclination angle of the separation surface. Large particles move upwards at angles of up to 5 degrees, and downwards at angles higher than 5 degrees. Vibration frequency and amplitude alteration, as well as adjusting the inclination angle of separation surface enables to move and adjust the speed of different properties and sizes of test material. The laboratory separator work is based on the physical effects, which enable to vary the location of the power pipe. This fact allows the construction to be adapted to a variety of specific conditions and expands the construction sphere. The separator construction is simple for production and operation, and can be quickly reconfigured if necessary. The separator portability allows it to be transported.
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Language style matching and verbal intelligence
Статья научная
In this paper language style matching of speakers yielding different verbal intelligence was analyzed. The work is based on a corpus consisting of 100 descriptions of a short film (monologues), 56 discussions about the same topic (dialogues) and verbal intelligence scores of the test persons. According to the results, higher verbal intelligent speakers showed a greater degree of language style matching when describing the film and were able to better adapt to their dialogue partners compared to lower verbal intelligent participants.
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Статья научная
Approaches and solutions in the area of forest remote sensing methods for the purposes of information support of inventory, monitoring and cadastre of forest lands with the use of innovation methods and high-end technologies of laser location, digital aerial survey and global satellite positioning are considered in the paper.
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Library of mathematical functions with parallelism at the operational level in the Pythagor language
Статья научная
At present, developed tools and libraries have been designed for imperative and functional programming languages that provide parallelism through processes or threads. There are other alternative approaches to the organization of parallel computing, one of which is implemented in Pythagor - the language of functional-streaming parallel programming, and involves parallelism at the level of operations. The tools of the Pythagor programming language are actively developing, and the repository of predefined functions is expanding. Many mathematical functions have been designed to provide a developer with no less functionality than the math library math.h of the C programming language. A large part of the mathematical functions have been implemented using the Maclaurin’s series. It is both used as an approach of faster and less accurate calculations, in which a predetermined number of elements of the series is calculated without cycles and recursions with the substitution of pre-calculated coefficients in the function code, and as an approach of less rapid and more accurate calculations, in which the elements of the series are calculated dynamically until the desired accuracy is achieved. The development of a library of mathematical functions of a programming language is an applied algorithmic task already implemented in one way or another for a number of existing programming languages. But in many languages, the implementation of algorithms for mathematical functions is hidden from the user, while modern tools of the Pythagor language support an open repository of functions. Additional interest is the possibility of parallelism at the level of operations in the calculation of mathematical formulas in the Pythagor language.
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Local search in bilinear two-person game
Статья научная
We consider an approach that allows reducing Nash equilibrium problem to a minimax problem for rather wide class of games using the so-called Nikaido-Isoda function. One can reformulate minimax problem as an optimization problem with nonconvex and implicitly defined objective function in general case. In other words, the set of Nash equilibria of the game is coincide with the set of global solutions of derived optimization problem. In present paper we investigate such an approach as applied to bilinear two-person game with quadratic loss functions and independent strategy spaces in view of an assumption that loss functions are strictly convex with respect to own players’ variables. In this case we suggest to replace “inner” optimization problem in minimax problem by Lagrange dual one. Such a way leads to presentation of the objective function as a difference of two convex functions (d.c-decomposition of the objective function). The very function in d.c-decomposition, that forms concave part, is defined implicitly as well as the objective function. We propose a method for linearization of concave term. That allows using the well-known local search method for d.c-functions, where the next iteration point is a solution of convex optimization problem with the objective function, which gained from initial objective by linearization of concave term in d.c-decomposition. Since the concerned problem is nonconvex, we offer to use local search in combination with multistart. The results of computational experiment are provided in the paper.
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M-апериодические слова над трехбуквенным алфавитом
Статья научная
Работа посвящена изучению множеств апериодических слов над конечным алфавитом. Множество апериодических слов можно рассматривать как словарь некоторого конечного формального языка. Существование бесконечных слов в двухбуквенном или трехбуквенном алфавитах, которые не содержат подслов, являющихся третьими степенями или, соответственно, квадратами других слов, впервые получены более ста лет назад. С. И. Адян в 2010 г. построил пример бесконечной последовательности несократимых слов, каждое из которых является началом следующего и не содержит квадратов слов в алфавите из двух букв. С. Е. Аршон установил существование n-значной ассиметричной бесповторной последовательности для алфавита не менее чем из трех букв. В монографии С. И. Адяна доказано, что в алфавите из двух символов существуют бесконечные 3-апериодические последовательности. В работах других авторов рассматривались обобщения апериодичности, когда исключались не только степени некоторых подслов. В монографии А. Ю. Ольшанского доказана бесконечность множества 6-апериодических слов в двухбуквенном алфавите и получена оценка количества таких слов любой данной длины. Автором ранее случай трехбуквенного алфавита рассмотрен только в случае 6-апериодических слов. В данной статье доказана бесконечность множества m-апериодических слов в трехбуквенном алфавите при m ³ 4 и получена оценка множества таких слов. Полученные результаты могут быть полезны при кодировании информации в сеансах космической связи.
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Magnetization of multilayer ferromagnetic film with a nonmagnetic interlayer
Статья научная
The magnetization of magnetic film, consisting out of two ferromagnetic layers with a nonmagnetic interlayer applied to antiferromagnetic substrate is considered in this paper.
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Magnetoelectric effect induced by orbital ordering of electrons
Статья научная
Relationship between orbital order and the formation of the spontaneous magnetic moment, lattice constant, correlation function of orbital and spin moments between nearest neighbors have been investigated in terms of the continuous Potts model for set of electron-phonon parameters and spin-phonon interactions. A change in the permittivity and orbital correlation functions in the external magnetic field has been found.
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Mathematical model for contact resistance of cold contact at spot welding
Статья научная
The paper is devoted to the problem of optimizing spot welding modes and contains the description of a mathematical model for the calculation of cold contact initial resistance.
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Mathematical model for geostationary spacecraft disturbing torques determination
Статья научная
Modern requirements to increase spacecraft active existence lead to the efficiency of all its resources use improve- ment. And one of the main spacecraft resources, which determines the period of active existence, is the orientation en- gines fuel. The fuel consumption of the orientation engines depends on the external disturbance torques affecting the spacecraft. The work is devoted to the development of a mathematical model that allows to determine external distur- bance torques continuously affecting the spacecraft. The mathematical model is based on the assumption that the ki- netic moment of the spacecraft remains unchanged in the inertial coordinate system. The use of an active flywheel ori- entation system makes it possible to measure a spacecraft kinetic and disturbance moments. A special feature of this measurement is the rigid connection of flywheels with the spacecraft body that rotates at an orbital speed. This feature makes it necessary to take into account the kinematic relationship of the flywheel kinetic moment with the kinetic and disturbance moments in the inertial space. Thus, according to the kinetic moment variation law, it was possible to ob- tain a mathematical model for the interrelation between the flywheel kinetic moment and external disturbance torques. To test the model, two of the most common methods of mean-square filter readings were examined: the Gaussian filter and the Kalman filter. Modeling systems of equations and coefficients of error matrices were determined for modeling. The model was tested in the GNU Octave mathematical computing environment using telemetry information received in 2017, from medium-sized spacecraft (based on the Express-1000H platform) and heavy (Express-2000) class. To com- pare the results, the graphs for calculating the kinetic moment from the model and the measured kinetic moment from the flywheels are given. The mean-square deviation of the compared values did not exceed 0.1 Nm for the Gaussian filter and 0.03 Nms for the Kalman filter. The graphs of disturbing torques estimation by a mathematical model are given. The mean-square deviation of the estimate of the disturbing torquess for the Gaussian filter did not exceed 0.9 % and for the Kalman filter it was 2 %. The convergence of the disturbing torques estimates shows the adequacy of the developed mathematical model.
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Статья научная
Operational characteristics of contacting elements of cars and mechanisms are by far defined by a layer quality indicators at the surfaces of contact. One of the ways of increasing details durability, including missile and space equipment details, is the superficial plastic deformation (SPD). In the article aspects of dynamic ways of hardening from the position of the wave theory of blow are considered. The construction of a shock stand on the basis of a linear electrodynamic drive with a size of 60 mm, operating in a shock-pulse mode, as well as a well-known mathematical model of the workflow - the movement of the armature with the tool at the moment of striking the surface. This model does not fully describe the operation process since the mass of the striker taken into account equaled 1 kg, which does not characterize the process of the impact tool, the purpose of which is the object deformation (for example, work hardening with the aim of surface material sealing or breakdown of the hole in it, or applying license plates markers). The mathematical model that describes the movement of the armature with the tool, taking into account the elastic deformation of the hardened surface was obtained. In the course of the performed calculation, the magnitude of the elastic deformation of the hardened surface was calculated from the dynamic component of the force impulse applied to it through the indenter (the tip of the impact tool). The layout of the shock stand with the equipment used, are offered. Experiments on the signal recording with various arrangements of piezoelectric transducers on the anvil - the hardened surface (diagrams of the sensors location are given) were carried out.
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Mathematical model of conducting nanopore for molecular dynamics simulations
Статья научная
An electrostatic model of conducting nanopore is presented in the paper. The model does not require solution of the Poisson equation for the potential. This model is intended for use in simulation of transport phenomena of charged par- ticles in conducting nanopores by the method of molecular dynamics. This method is based on Newton’s equations of motion and it allows one to determine the variation of position, velocity and acceleration of particles with time. The electric field from the charge distributed over the nanopore surface is approximated by the field from fictitious point charges on the same surface. To verify the proposed model of fictitious charges system capacitance is calculated. The obtained values of capacitance are compared with classical results for conducting tubule and with the results obtained by the other similar method. The comparison shows that relative discrepancy between results is less than 10 %. There is a need to further develop the proposed model both in case of a large number of fictitious charges and in case when charged particles are in close proximity to the nanopore surface. The proposed method can be easily applied to an ar- bitrary shape nanopore. The model can be used in the development of various nanodevices, among them the devices used in life support systems of manned space vehicles.
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