ISSN 0021-3454 (print version)
ISSN 2500-0381 (online version)
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Summaries of the issue

COMPUTER TECHNIQUE

101
The frequency of use of computer commands in implementation of three typical algorithms is analyzed. The object of the study is the command system of software model of a training computer. As an example, analysis of three programs in mnemonics is carried out, the programs correspond to three algorithms: a branching algorithm, an algorithm that handles elements of an array, and an algorithm using a subroutine. The established proportion of used and repeated commands in the process of solving problems confirms the validity and applicability of the principle "20/80" – the Pareto principle, which in the most general form can be formulated as "twenty percent of the efforts give eighty percent of the result, the remaining eighty percent provide only twenty percent of the result". Based on the results, the conclusion is made about the redundancy of the computer command system, leading to complication of the computer control device. As one of the possible ways to reduce the number of commands, it is suggested to reduce the conditional jump commands. The approach is supposed to provide a reduction in composition and structure of control devices of both hardware and firmware types.
106
A method for constructing a code with summation of single information bits is presented. When constructing a code with summation, it is proposed to calculate the modified weight of the information vector by determining the smallest nonnegative deduction of its true weight using a predetermined module, and then correct the resulting number using two correction factors. These coefficients are calculated as convolutions modulo two of some different subsets of bits of the information vector. The code thus obtained is a three-modular code with the summation of single information bits, it is comparable in its redundancy with the classical Berger code but allows better detection of errors in the information vectors. Three-modular codes with summation extend the class of known codes with low redundancy, the use of which allows reducing the structural redundancy of testable discrete devices and technical means of diagnosing their components.

OPTICAL AND OPTO-ELECTRONIC INSTRUMENTS AND SYSTEMS

SIMPLE SCHEMATIC OF FIBER-OPTIC SENSOR OF ANGULAR VELOCITY Dmitry A. Matryokhin, Alexander N. Tynynyka
117
Specifics of design of fiber-optic sensors used in gyroscopes for civil and military purposes are discussed. The specifics are reported to cause additional requirements for radiation sources: compliance with the wavelength of radiation of the nominal wavelength of the light guide, where the loss is minimal; sufficiently high efficiency of the input of radiation into the light guide; the possibility of a radiation source operation in continuous mode without cooling; a sufficiently high level of the output power of the radiator; durability, reproducibility of characteristics, rigidity of the structure, as well as minimum dimensions, weight, power consumption and cost. Parameters of the sensor design that have the greatest impact on its sensitivity are considered. A block diagram of an inexpensive fiber-optic angular velocity sensor providing the specified technical parameters is proposed. The features of the block diagram components are considered, including the radiation source, connectors, polarizer, optical fiber, as well as design of the sensor coil, phase modulator, etc.
123
Liquid lenses, the geometric shape (radius of curvature) and, consequently, the optical power of which are regulated by changing the intra-lens fluid pressure, are developed. Results of experimental testing of electrically controlled liquid lenses on a hydraulic basis are demonstrated. The presented version of the design with an electromagnetic actuator serves as the basis of the lens for night vision glasses. The optical scheme and technical characteristics of the lens are given.
APPLICATION OF SCANNING INTERFEROMETRY OF LOW-COHERENCE LIGHT TO MEASURE DEMINERALIZED AREAS OF THE ENAMEL UNDER THE GUM in vivo Prokopenko Victor T., Majorov Evgeniy E., Ludmila I. Shalamay, Khokhlova Marina V., Maria S. Turovskaya, Anastasiia S. Ushakova, Dagaev Alexander V.
128
A low-coherence interferometer of scanning type for tomographic studies in therapeutic dentistry is presented. The features of low-coherence interferometry, which is a unique tool for the determination and analysis of demineralized areas of enamel under the gum in vivo, are considered. It is shown that at a normal incidence of probing radiation at depths from 2000 to 3000 µm, it is possible to measure enamel demineralization with an error of not more than 2.1 µm. The obtained tomograms make it possible to detect in vivo demineralization of enamel under the gum at an early stage of its formation.
OPTICAL INFRARED RANGE SYSTEM WITH ACTIVE FOCUSING FUNCTION Vladimir N. Vasiliev, Igor Yu. Dmitriev, Vsevolod A. Muravev, Ezhova Ksenia V
136
Methods and means of active focusing for optical systems of IR spectral range, used to retain the spatial and energy resolution of the optical-electronic equipment in operating conditions are examined. Active focusing using the built-in test emitter located in the intermediate image plane of the IR optical system is proposed. A criterion of focusing based on an analysis of output signals of multi-element photo-receiving device is considered, sensitivity of the criterion to defocusing value of the optical system is numerically estimated. High sensitivity of the proposed focusing method and technical feasibility of the focusing tools in an optical system used in combination with serial samples of medium-wave and long-wave IR matrix photodetectors with a cooled aperture diaphragm are demonstrated. It is recommended to use the developed method and focusing tools as a part of onboard optoelectronic observation equipment operated in automatic mode in a wide temperature range.
LASER-INDUCED DAMAGE THRESHOLD OF REFLECTIVE DIELECTRIC COATINGS ON ABSORBING SUBSTRATE Khramov Valery Yu., Gagarsky Sergey V., Andrey N. Sergeev, Radik M. Akhmadullin
142
Several features of HfO2/SiO2 and Ta2O5/SiO2 coatings deposited on absorbing substrate of single-crystal silicon carbide (SiC) are revealed to cause a decrease in their laser-induced damage threshold. It has been experimentally shown that in the presence of transverse micro displacement of the beam during the measurements, the radiation strength of the sample decreases in 2–3 times. Using the heat transfer equation and the finite element method in the CAE (computer-aided engineering) system, the effects of laser radiation with transverse beam displacement is simulated, and the dynamics of temperature changes and induced thermal stresses inside the samples are evaluated.

HEAT REGIMES AND RELIABILITY OF INSTRUMENTS AND SYSTEMS

150
Several aspects of design and operation of modern marine power plants – namely, operational reliability and economic efficiency of the plants - are considered. Application of thermal imaging measurements technology is proposed as a mean to solve the first problem, and the technology of fluidized bed is suggested to solve the second one. Examples are given, a justification is provided, and ways to solve the problems are described. It is shown that introduction of thermal measurements in on-board control system will best meet the modern requirements for the economy and safety of marine power plant operation.
CRITERIA OF ISOTHERMALITY OF SPACE OBJECTS ON THE EXAMPLE OF A HOLLOW CUBE IN THE EARTH SHADOW Dzitoev Azamat M., Lapovok Yevgeniy V., Pen’kov Maxim M., Khankov S.I.
156
A method for determining the conditions of maximum non-isothermality and total isothermality of a space object in the form of a hollow cube in the shadow of the Earth is proposed. The object has a shell structure with a constant wall thickness, and its base lies in the plane of the local horizon. Streams of own thermal radiation of the Earth is falling on the lower base surface and the side surface of the object. All external surfaces of the object emit thermal energy into space. In the inner cavity of the object, heat is exchanged between the internal surfaces by radiation. All internal and external surfaces of the object are assumed to be completely black. The developed method is based on evaluation of the range of thermal conductivity of walls of equal thickness, for which the heat exchange between the faces of the cube is determined only by internal re-emission and does not depend on the thermal conductivity of the walls. This case corresponds to an extremely non-isothermal object. Then the average temperature of each of the surfaces of the object with a thin wall should be determined, when the effect of thermal conductivity on the alignment of temperatures on the surface of the object is negligible. Another limiting case corresponds to an isothermal object.

SCIENTIFIC AND PRACTICAL DEVELOPMENTS

FORMATION OF VAPOR CAVITY UNDER HYDROACOUSTIC TREATMENT OF BIOLOGICAL TISSUE IN LIQUID BY MICROSECOND PULSES OF Er,Yb:Glass-LASER RADIATION Belikov Andrei , Gagarsky Sergey V., Zagorulko Alexey M., Andrey N. Sergeev, Smirnov N Sergey
163
Results of a study of dynamics of the shape and size of vapor-gas cavities excited by laser pulses on ytterbium-erbium glass with a fiber output at a wavelength of 1.54 µm in the free volume of liquid (water), as well as near boundary of a solid (quartz) and elastic object (lens of the eye) are presented. The influence of temporal structure of the pulses of total duration in microseconds on appearance and process of formation of the vapor cavity in liquid is investigated. It is found that at a fixed pulse energy in the free volume of the liquid, an increase in the power of the "leading" peak in the laser pulse leads to a decrease in the threshold of formation and an increase in the maximum volume of the cavity. In the free volume of the liquid with a total laser pulse duration of 3–3.5 µs and energy of the order of E = 100 mJ, the maximum volume of the vapor-gas cavity reaches 7 mm3 at the laser radiation intensity of the order of 108 W/cm2 at the output end of the optical fiber at the time of the action of the leading peak. The maximum volume of the vapor-gas cavity is achieved within 165 ± 5 µs from the beginning of the laser pulse, and the cavity collapse occurs after 300 ± 10 µs. Reducing the intensity while maintaining the total energy of the pulse leads to a slowdown in the growth of the vapor-gas cavity and a decrease in its maximum volume. Near the boundary of the solid, the vapor-gas cavity is deformed and acquires a smooth hemispherical shape, its volume decreases, and the lifetime increases to 350 ± 10 µs. Near the border of the elastic body, the vapor-gas cavity is also deformed, acquires a hemispherical shape, but in the collapse phase near the lens, micro bubbles of 40–120 µm size are formed on the surface of the cavity. Near the cataract lens, the time to reach the maximum volume of the cavity and the time of its life are reduced compared to the formation near the boundary of the solid and in the free volume of water, and the lens of the eye is destroyed.
178
The process of integrating two CAD systems is considered, Altium Designer and Solid Edge, is considered from the point of view of desirable reduction of terms of designing of electronic equipment. The format of three-dimensional models is studied for the purpose of conversion from ECAD to MCAD and the further design of electronic equipment and two-dimensional models are investigated for the purpose of conversion from ECAD to MCAD for registration of the design documentation. Recommendations on export settings in the CAD are formulated and the ways to further development of the model for the design engineering documentation according to GOST are suggested. Application of the results are expected to allow to quickly draw up design documentation for GOST ESKD and perform end-to-end design of electronic equipment, including different types of printed circuit boards. As a result, it may reduce the design time, reduce the number of errors in the end-to-end design, comply with GOST and improve the efficiency of using CAD.
185
Automation of diseases diagnostics is an actual direction of development of electrophysiological studies of human digestive system. The relevant research work needs to include the procedures of com-puter analysis of experimental data arrays. However, there are no technological solutions for organized storing and accumulation of such arrays. An architecture of software system for formation of data ware-houses of electrogastrography and electrogastroenterography from different types of sources and preparation of statistical samples for subsequent computer processing is proposed. The architecture is based on the design pattern of Mediating-controller MVC, which provides a high degree of decomposition of the system. The system developed in Python 3 is freely distributed.

BRIEF NOTES

METHODOLOGY OF DESIGN AND ANALYSIS OF SMALL GEARS FROM COMPOSITE MATERIALS Medunetskiy Viktor M. , Shalobaev Evgeniy Vasilievich, Vladimir A. Zinkov, Dang Nhan Thong
192
The task of creating a general engineering methodology for the design of small-sized gears is justified. The problem is adapted to real conditions and does not require the user to be highly skilled in the field in question. The proposed methodology allows one to consider the features of design of gears from polymeric composite materials. The stages of the methodology are described briefly.