Статьи журнала - Журнал Сибирского федерального университета. Серия: Техника и технологии
Все статьи: 1404
Synthesis of Ca4GdO(BO3)3 single crystals using Czochralski method
Статья научная
The oxoborate Ca4GdO(BO3)3 (GdCOB) is a potential material for advanced industrial applications because of its optical and electric properties. High quality single crystals of GdCOB have been grown from a melt using the Czochralski method. Single crystals of laboratory scale are of good optical quality showing no macroscopic defects like cracks, inclusions or discolouration. Crystals in [001] direction reveal regular growth, whereas crystals in [010] are of asymmetric shape but show less difficulties during the growth process.
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Synthetic fuel production: thermal behavior of lemon and orange peels composite fuel diesel
Статья научная
This study aimed to investigate the thermal combustion behavior of lemon peel powder, LPP and orange peel powder, OPP composite fuel diesel. The pyrolysis experiments of the diesel/ citrus composite fuel were conducted in combustion chamber. The results showed that the citrus/diesel composite fuel sustains its combustion properties at 30 % of the added citrus peels powder,. The results showed that calorific values of diesel containing 30 % LPP or 15 % LPP + 15 % OPP were very close to that of the pure diesel. The maximum calorific values were obtained at α = 0.85, 0.80 and 0.90 for 30 % OPP, 30 % LPP and 15 % OPP + 15 % LPP composite fuels respectively.
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Systems of automated exploration of radio-technical systems of the aviation flights service
Статья научная
There is a review of the way of training and retraining of radio-technical systems operators by using system of automated exploration, which is able to identify and manage the individual training program.
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Статья научная
The use of the newest methods and technologies of airborne laser location, high resolution digital photography and the global positioning satellite systems, provides principally new opportunities for remote sensing monitoring and inventory of forest resources. High efficiency of laser location (more than 200 thousand pulses/measurements per second) in combination with centimeter spatial resolution of digital aerial photography, high (about 10-15 cm) accuracy for coordinate definition of trees and tree stands morphostructural parameters by satellite geopositioning systems, as well as three-dimensional visualization of the remote sensing data at geoinformation systems, allows to developing effective algorithms for research of forest resources structure and dynamics, guaranteeing a real time automatic extraction of forest inventory parameters. Development and application of such high-end technologies to aerospace forest monitoring is critical and essential for boreal zone and, in particular, for regions of Siberia, where traditional approaches of forest inventory to be used today are not effective, do not provide required accuracy and are highly timeand funds consuming.
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Telemetry, command and ranging system of geo spacecraft
Статья научная
The article describes the telemetry, command and ranging system of GEO spacecraft. It addresses RF signals passage in ground-to-spacecraft path. Results of RF link budget calculations are presented. The article also addresses unaccountable parameters of using onboard and ground equipment having performances required by the link budget. System operation in ranging mode is described, as well as the existing problems of its usage. Prospects of existing disadvantages handling and system performance improvement were given.
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Статья научная
The Chiemgau strewn field in the Alpine Foreland discovered in the early new millennium comprises more than 80 mostly rimmed craters in a roughly elliptically shaped area with axes of about 60 km and 30 km. The crater diameters range between a few meters and a few hundred meters. Geologically, the craters occur in Pleistocene moraine and fluvio-glacial sediments. The craters and surrounding areas so far investigated in more detail are featuring heavy deformations of the Quaternary cobbles and boulders, abundant fused rock material (impact melt rocks and various glasses), shock-metamorphic effects, and geophysical anomalies. The impact is substantiated by the abundant occurrence of metallic, glass and carbon spherules, accretionary lapilli, and of strange matter in the form of iron silicides like gupeiite and xifengite, and various carbides like, e.g., moissanite SiC. The hitherto established largest crater of the strewn field is Lake Tüttensee exhibiting an 8 m-height rim wall, a rim-to-rim diameter of about 600 m, a depth of roughly 30 m and an extensive ejecta blanket. Physical and archeological dating confine the impact event to have happened most probably between 1300 and 300 B.C. The impactor is suggested to have been a low-density disintegrated, loosely bound asteroid or a disintegrated comet in order to account for the extensive strewn field.
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The GaN era has arrived in Satcom power amplifiers
Статья научная
In this paper features, characteristics and comparisons of gallium nitride high electron mobility transistors (GaNHEMTs) power amplifiers are considered.Maximum operating temperature widespread now, gallium arsenide GaAs transistors is 175 o C. They are inferior to the transistors based on gallium nitride GaN, and keep steadily working frequency characteristics at operating temperatures up to 250 0 C. This greatly reduces the problem of heat removal. These transistors operate at voltages up to 100 V against the maximum of 20 V for GaAs transistors at equivalent power output. Therefore, GaN transistors and power amplifiers, they are particularly relevant for applications in space exploration. In Paradise Datacom (USA) designed power amplifiers in different ranges of frequencies with a power output of up to 50 to 750 watts.
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The Stefan problem solution by the moving boundary conjugate equation
Статья научная
The conjugate equation, describing intensity of phase transformation of a substance on the moving boundary, is used in the Stefan problem instead of the traditionally applied boundary condition of the fourth type (Stefan condition). At the numerical solution of the problem on the one hand the conjugate equation allows to carry out the shock-capturing method without reorganization of grid areas, on the other hand - accurately trace the position of the moving boundary. The estimation of adequacy of the wet ground layer freezing process mathematical modeling in the new statement is carried out to the real process.
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The ability of quantum dots formation in thin nanostructured amorphous films
Статья научная
In the last years an interest in field of quantum dots devices creating has been increased. In this work the nanocrystallite with Frank-Kasper structure was examined as the quantum dot in amorphous film. An ability to create all-inorganic Quantum Dots Light Emission Device may be considered for Tb 30 Fe 70, Co 80 C 20, Fe 86 Mn 13 C and Co 50 Pd 50 films. The self-organisation of atomic structure in Tb 30 Fe 70, Co 80 C 20, Fe 86 Mn 13 C and Co 50 Pd 50 films, which possess large values of perpendicular magnetic anisotropy (PMA) constant (K ⊥ ~ 10 6 erg/cm 3 ), were investigated by methods of electron diffraction and transmission electron microscopy, including the method of bend contours. The crystallization of the films proceeds in an explosive way forming different dissipative structures from initial nanocrystalline state. In previous works [2, 3] it was shown that after crystallization (Т ann ~ 260-330 °C) the atomic structures of Tb 30 Fe 70, Co 80 C 20, Fe 86 Mn 13 C and Co 50 Pd 50 films are tetrahedrally close-packed Frank-Kasper structures. In this work the structural model of thin film at mesoscale and its correlation with magnetic and optical properties is proposed.
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Статья научная
For crystals grown from a liquid melt using the Czochralski method, under the control of the current area of the crystal on the basis of the contact measurement method, defines the requirements for ensuring the accuracy of measuring the value of 1 %.
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The algorithm for compensating distortion of images of type “blur”
Статья научная
The paper considers the model of linear blurring with a uniform rectilinear motion of an object when its speed is constant, and its direction is parallel to the lines of the formed image. An algorithm for linear blurring compensation based on the account of the physical processes of its formation when obtaining the images is proposed. A system of equations for the restoration of the original video signal samples undistorted image of the object is obtained. Processed the frame of a real video sequence with a horizontal blur and presented its results. Considered the comparison of the results of the restoration of distorted images by the proposed algorithm with known methods.
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The alumina dissolution in industrial aluminum cells
Статья научная
The dissolution behaviors of primary and secondary alumina in aluminum bath were compared. The dissolution of primary alumina can be divided into a few key steps: fast dissolution upon feeding, crust formation and sludge dissolution. The dissolution rate of secondary alumina is much faster than that of primary alumina. Industrial measurements of alumina concentration in 410 kA and 500 kA cells confirmed the laboratory results.
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The analysis of modern information and fire conflict distinctive features
Статья научная
The article dwells upon the role of information superiority in achieving the geopolitical goals. The stages of states and their allies’ opposition are considered. The importance of overtaking the opposing force in reconnaissance is explained. The military-system analysis of initial conflict opposition characterizing the high degree of tension and further development of this opposition, main tendencies of intelligence gathering systems are stated.
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Статья научная
In article considered questions of the choice of maximum filling billets during cold rolling of aluminum alloy tubes according to a given degree of deformation for the different methods for calculating the profile of a stream caliber.
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Статья научная
Operation is devoted a problem of identification of dynamic system of the volume hydraulic actuator of the running gear of a vibrating roller. The mathematical model of control process by speed of driving of a vibrating roller taking into account dynamics of hydrostatic transmission and a moment of resistance to roller driving is observed. Assay values of dynamic responses, a frequency analysis of a model of a guidance system are resulted by speed of driving of a vibrating roller.
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Статья научная
The laser analyzers MAYA are successfully applied in industry in order to solve the tasks of crushed ore sorting and stabilization of the composition if raw material mixtures in metallurgy and in production of fireproof materials. The tests of non-ferrous ores such as Cu, Mo, Zn, Pb, Sn, Ti, Be, Sr and Ba confirm that the laser analyzers could be applied in this branch at different stages of the technological process: extraction of raw material, preparation of raw material mixture, check of technical composition, operative check of the finished products’ quality.
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Статья научная
In bulk and thin film state Fe86Mn13C alloy observed experimentally self-assembly of the crystal and magnetic structures on multiscale levels. Offered self-assembly cluster model of atomic structure based on the concept of a liquid-like state of the material in localized areas, formed in the waves of plastic deformation.
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Статья научная
A brief description of deterministic and probabilistic-statistical methods for calculation of electricity losses in the distribution networks of 6-35 kW. The optimal combination of weight deterministic and probabilistic and statistical approaches in the combined calculation of power losses by criterion of a minimum of errors.
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Статья научная
This article reveals the features of the channels of hyperspectral aerospace images. There has been suggested the algorithm with interchannel finding of the best channel of intrabands correlation and the use of indexed lossless encoding, which allows to reduce the dimensions of the image channels and to convert them before compression. Also the article shows the results of experiments in comparison with universal archivers such as Winrar, 7Z, and JPEG Lossless according to the compression degree and several parameters: the interchannel correlation, geometric image size, number of channels, number of channel groups. Furthermore, the author of the article studies the options of compression with the search of the main channel of the correlation and without it; these options demonstrate the increase in compression degree due to diff erential transformations, which allow to store the information in a more compressed form.
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Статья научная
The influence of furnace operating conditions on the heat transfer in Vanyukovs smelting energotechnological complex has been researched on the basis of its polyzonal mathematical model. The quantitative relations have been found allowing to run the melt more effectively to maintain melting temperature required by the technology when composition of matte being constant. The recommendations for efficient operation mode of lining cooling under layer space of the furnace were given.
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