Properties of high-temperature superconductors (HTS) and synthesis technology

The main results for the synthesis and study of superconducting high-temperature materials based on cuprates obtained by high-temperature synthesis are presented. The influence of the ratio of the primary components, time and exposure temperature on the output of the superconducting phase (Y123) in the composition was studied. It was found that the initial ratio of components, annealing temperature and aging time have a direct impact on the qualitative and quantitative formation of the conductive phase. The chemical, phase composition and morphology of the obtained samples were carefully studied. Optimal result (maximum conductive phase in Y-Ba-Cu-O system (Y123) size) at a temperature of 920°С with a retention time of 6 hours

Effect graphite on magnesium diboride superconductivity synthesized by combustion method under argon pressure: Part I

Solid-state synthesis of a superconductor based on magnesium diboride doped by graphite microparticles (MgB2@C) at argon atmosphere has been described. The offered method allows the possibility to increase the critical current density of the studied samples at relatively low temperature in the inert environment. The superconducting characteristics of samples critical current density (Jc) and critical transition temperature (Tc) have been measured. The impact of the doping additives on superconducting characteristics of magnesium diboride has been analyzed. The results showed that the best optimal characteristics are for MgB2@3%C that reveals a good critical transition temperature 38,8 K and the higher critical current density 2,7 x 106 A / cm2 at 5 K

Effect graphite on magnesium diboride superconductivity synthesized by combustion method under argon pressure: Part II

There are many various techniques to synthesize the superconductors based on magnesium diboride. In this paper, we attempted to obtain a superconducting magnesium diboride in a way by using a High-Temperature Centrifuge and investigated how a centrifugal force can be effect on superconducting parameters of MgB2 during solid-state combustion. It was the first superconductor based on magnesium diboride synthesized under the influence of centrifugal force in the high temperature centrifuge during solid phase process. As a result of this research, we could determine that a centrifugal force do not impact considerably on the critical transition temperature of the MgB2 samples (stay at around 37,5 – 38 K). However, it was found that the value of a centrifugal force could effects on the critical current density (Jc) of the samples

Effect graphite on magnesium diboride superconductivity synthesized by combustion method under argon pressure: Part I

Solid-state synthesis of a superconductor based on magnesium diboride doped by graphite microparticles (MgB2@C) at argon atmosphere has been described. The offered method allows the possibility to increase the critical current density of the studied samples at relatively low temperature in the inert environment. The superconducting characteristics of samples critical current density (Jc) and critical transition temperature (Tc) have been measured. The impact of the doping additives on superconducting characteristics of magnesium diboride has been analyzed. The results showed that the best optimal characteristics are for MgB2@3%C that reveals a good critical transition temperature 38,8 K and the higher critical current density 2,7 x 106 A / cm2 at 5 K

Method of increasing the accuracy of the star sensor

A new algorithm for filtering distortions of the deep image of the starry sky is considered to improve the accuracy of determining the position of the star - the detection of the centroid. An increase in the accuracy of measuring the orientation parameters of the spacecraft by stellar sensors is being investigated. The method of calculations using the algorithm of exact estimation of the centroid is applied, restoring the function of the scatter of points from recorded astronomical images. Minimization of the effects of atmospheric turbulence and system noise on longexposure images obtained by a ground-based telescope is proposed. The method was tested in the MATLAB environment for a real image of the deep sky recorded by the ground system.Розглядаються новий алгоритм фільтрації спотворень глибокого зображення зоряного неба для підвищення точності визначення положення зірки - виявлення центроїда. Досліджується підвищення точності виміру параметрів орієнтації космічного апарату зірковими датчиками. Застосований метод обчислень, що використовує алгоритм точної оцінки центроїду, що відновлює функцію розкидання точок за астрономічними зображеннями. Запропоновано мінімізацію ефектів турбулентності атмосфери та шумів системи на зображеннях із тривалою експозицією, отриманих наземним телескопом. Метод перевірено у середовищі MATLAB для реального зображення глибокого неба, записаного наземною системою

About the Perturbing Factors Influence in the Spacecraft Motion Simulation Model

Abstract The new simulation model of the spacecraft's center of mass motion with taking into account of gravitational potentials of the Earth, the Moon and the Sun is presented in this paper. The simulation model was created on the basis of analysis of the present mathematical models of gravitational potentials of the Earth, the Moon and the Sun and different methods of numeral calculation. Influence of the Earth's atmosphere, which causes the spacecraft motion deceleration, was taken into account. By means of the created simulation model the analysis of the environment perturbation factors influencing on the spacecraft motion trajectory was carried out. It has been revealed that deviation of the calculated orbit from the given one depends on orbit height, and this dependence has been defined. The estimation of relative influence of the moments of various forces on the mass center motion was carried out

Досягнення та перспективи створення систем визначення орієнтації малого космічного супутника

Досягнення у сфері створення малих супутників разом із доступністю недорогих запусків призвели до збільшення кількості космічних польотів. Оскільки космос стає більш доступним, ніж будь-коли раніше, виникають нові та новаторські місії. Показано сукупність досягнень у галузі автоматичних систем, приладів систем управління, обчислювальних систем, виконавчих органів систем управління, способів та методів комплексування систем управління, що дозволили створити багатоцільові, багаторежимні системи з тривалим циклом активного життя, системи з максимальною автономністю та автоматизацією процесів управління. У цій статті представлені досягнення та перспективи систем управління космічних апаратів за останні три десятиліття. Розглянуто проблемні питання підвищення точності орієнтації та стабілізації.Advances in the development of small satellites, combined with the availability of low-cost launches, have led to an increase in the number of space flights. As space becomes more accessible than ever before, new and innovative missions are emerging. A set of achievements in the field of automatic systems, control system devices, computer systems, control system executive bodies, methods and methods of control system integration, which made it possible to create multi-purpose, multi-mode systems with a long active life cycle, systems with maximum autonomy and automation of control processes, is shown. This article presents the achievements and prospects of spacecraft control systems over the past three decades. The problematic issues of increasing the accuracy of orientation and stabilization are considered

Properties of high-temperature superconductors (HTS) and synthesis technology

The main results for the synthesis and study of superconducting high-temperature materials based on cuprates obtained by high-temperature synthesis are presented. The influence of the ratio of the primary components, time and exposure temperature on the output of the superconducting phase (Y123) in the composition was studied. It was found that the initial ratio of components, annealing temperature and aging time have a direct impact on the qualitative and quantitative formation of the conductive phase. The chemical, phase composition and morphology of the obtained samples were carefully studied. Optimal result (maximum conductive phase in Y-Ba-Cu-O system (Y123) size) at a temperature of 920°С with a retention time of 6 hours