Home – Home – Jornals – Avtometriya 2012 number 4

A new version of the method of direct multibeam laser writing of diffractive optical elements (DOE) is proposed and investigated. A writing area in the form of an array of focused light spots is formed by splitting the writing laser beam into multiple beams by using a Dammann grating and focusing of these beams in the plane of a moving carrier with a photosensitive material. Adjustment of the radial pitch of writing and correction of the uniformity of the beam intensity is carried out by tilting the Dammann grating and displacing it in the dispersion direction. In writing DOEs, the radial pitch of discrete displacement of the writing area with respect to the plane of the DOE is set equal to or multiple of the average radial distance between the radial projections of the centers of the focused light spots. This version provides improved performance and accuracy due to high-quality paralleling of the writing beam and the averaging effect in superimposed writing.

The quality of the image formed by a MIOL-Akkord bifocal intraocular lens (diffractiverefractive lens) implanted into various known eye models is studied analytically. As the pupil radius increases, the Strehl ratio characterizing the resolution is demonstrated to decrease appreciably (down to 0.05-0.09) for models where the absolute value of asphericity of the frontal surface of the cornea is smaller than or equal to 0.26 (far vision) and 0.18 (near vision). The effect of the aspherical shape of the rear surface of the cornea on the image quality is considered. It is noted that the best results for both far and near vision are provided by the model with Lotmar's cornea for which the diffractive component of the MIOL-Akkord eye lens is calculated.

The configuration of a two-beam interferometer with fixed inclined mirrors for recording holographic gratings is described. The convergence angle of the partial beams is adjusted in the range from 0 to 180º by changing the angle of incidence of the primary beam on the entry edge of the beam-splitting cube without additional adjustment of the mirrors. The path lengths of the interfering beams are automatically aligned by the mirror symmetry of the system. The optimal kinematics of adjusting the convergence angle is found that allows working with beams of sufficiently large diameter in the whole range of adjustment. The interferometer is highly resistive to vibration due to lack of adjustment devices.

A 3D image in the form of a linear combination of two two-dimensional images located at different depths along the line of vision of the eye is considered. The loss of contrast and nonlinearity of accommodation over the depth with a high resolution acuity of 3D images are demonstrated in computer experiments with different eye models.

Numerical simulation was used to demonstrate the possibility of designing a two-mirror multibeam reflective diffraction interferometer using a single-mode fiber with a cladding. The method is based on the calculation of the multimode and multibeam interference of the cladding modes in the fiber describing the diffraction on a diffuser made in the form of an insert of a different fiber as part of one of the interferometer mirrors. It is shown based on bulk optics that using certain optimization, one can obtain a reflection-response function profile of this interferometer similar to that of the transmission-response function of a Fabry-Perot interferometer.

The dependence of the diffraction efficiency of polarization holographic gratings on the temperature of their formation is presented. The temperature range corresponding to the maximum diffraction efficiency of such gratings is determined. The possibility of thermo-optical switching of recorded gratings is demonstrated.

The architecture of silicon multiplexers for multielement IR photodetectors is considered. A review is given of industrially oriented developments of linear (1 × 32, 1 × 288, 1 × 576) and matrix (32 × 32, 128 × 128, 160 × 128, 320 × 256) silicon multiplexers for mid- and far-IR photodetectors based on cadmium-mercury-tellurium, lead-tin-tellurium, and multilayer structures with quantum wells. An analysis is made of the temperature resolution of matrix IR photodetectors based on multiplexers with row and frame integration of photo signals using micrometer to deep submicron CMOS technologies. Typical parameters of the multiplexer and some of the infrared photodetectors designed at the Rzhanov Institute of Semiconductor Physics, SB RAS are given.

A device for studying the relaxation dynamics of nonequilibrium capacitance and charge in the mode of nonequilibrium depletion of MIS structures is designed. Methods of measurements were developed that provide a sensitivity of 0.03 pF and 0.02 pC along the capacitance and charge measurement channels with the acceleration time 1.5 µs and 0.7 µs, respectively. The results are obtained with a double amplitude of the test signal of capacitance measurement of ~15 mV and frequency 5 MHz. A mode of measuring the capacitance-voltage characteristics with a scanning duration up to 100 s is implemented.

This paper presents results of a study of vortex wake structures and measurements of instantaneous 3D velocity fields downstream of a triblade turbine model. Two operation modes of flow around the rotor with different tip speed ratios were tested. Initially the wake structures were visualized and subsequently quanti-tative data were recorded through velocity field restoration from particle tracks using a stereo PIV system.
The study supplied flow diagnostics and recovered the instantaneous 3D velocity fields in the longitudinal cross section behind a tribladed rotor at different values of tip speed ratio. This set of data provided a basis for testing and validating assumptions and hypothesis regarding classical theories of rotors.

The influence of the vibrational relaxation on suppression of the Kelvin-Helmholtz instability in an evolving shear layer of a vibrationally nonequilibrium diatomic gas is studied numerically on the basis of equations of two-temperature aerohydrodynamics. Planar waves with the maximum growth rates, which were computed within the framework of a linearized system of equations of inviscid two-temperature gas dynamics, are used as the initial disturbances. It is shown that relaxation of the nonequilibrium vibrational mode at excitation levels, which can be obtained in diatomic gases in nozzle flows, in underexpanded jets, or in flows with moderate laser pumping, is accompanied by noticeable suppression of vortex disturbances. The associated relative enhancement of dissipation of kinetic energy of a large vortex structure averaged over its lifetime reaches approximately 13 %.

The analytic solution (in the form of the Neumann series) has been derived for the problem of computing the heat flux in a planar channel in the presence of a pressure gradient parallel with the walls (in the problem of planar Poiseuille flow) within the framework of the kinetic approach for arbitrary values of the Prandtl number. The ellipsoidal-statistical model of the Boltzmann kinetic equation is used as the governing equation, and the model of diffuse reflection is used as the boundary condition. The conducted numerical analysis of final expressions obtained in the present work showed a substantial dependence of the heat flux on the value of the Prandtl number of gas for channels whose thickness is comparable with the mean free path of gas molecules.

Results of an experimental study of the effect of flat mesh screens on the wave drag of a cylinder with flat face longitudinally streamlined with supersonic airflow at Mach number М = 4.85 are reported. Data on reducing the drag by meshes of various geometries and transparencies installed ahead of the cylinder face were obtained. Weighing and pneumometric measurements, and also PIV measurements of the vector velocity field, are reported. The flow pattern in the vicinity of the cylinder/screen system is visualized. It is shown possible to achieve a substantial (up to 45 %) reduction of the wave drag of the cylinder with a mesh screen. A physical interpretation to the wave-drag reduction phenomenon is given.

The interaction of disturbances in a boundary layer of the compressible gas is considered in the linear and nonlinear approximation (the weakly nonlinear theory of stability) in the presence of mass exchange (gas blowing or suction) on the surface. The regimes of moderate (the Mach number М = 2) and high (М = 5.35) supersonic velocities of the flow are considered. The suction from the surface is shown to lead to a considerable variation of the linear evolution of disturbances: the vortex disturbances of the first mode and the acoustic disturbances of the second mode are stabilized, the rate of variation is determined by suction intensity. The nonlinear interactions in three-wave systems between the vortex waves in asymmetric triplets at М = 2 and between the waves of different nature (acoustic and vortex waves) ⎯ in the symmetric ones at М = 5.35 are considered. The planar acoustic wave is the excitation wave in the latter, which excites the three-dimensional subharmonic components of the vortex nature. It is shown that one can delay considerably the transition region with the aid of suction, thereby one can reduce the skin-friction drag. In the gas blowing regime, strong deformations of the mean fields of boundary layers occur, which lead to the destabilization of the vortex and acoustic waves in the linear region and activate the nonlinear processes in transition region. One can expect that this will lead to the acceleration of tripping in supersonic flow.

Impingement of supersonic jet upon substrate surface, in front of which conical separation zone is created artificially with the aid of a spike or particle under conditions typical of cold spraying on geometric and dynamic parameters, is considered. Numerical simulation is carried out. Simulation results are in qualitative agreement with experimental observation data. Preliminary analysis of obtained pattern of supersonic jet impingement shows that in local ring area, creation of more favorable conditions for cold spraying of fine particles sized 1 micron or less is possible comparing to typical conditions.

Supersonic flows of gas in the vicinity of the bottom region known as flows with sudden expansion have been considered. On the basis of extensive experimental studies, authors have proposed a complete classification of flow regimes: stationary, oscillating, and transient. Hysteresis of the regimes change at total gas pressure increasing and decreasing in front of the nozzle has been found. Typical shock-wave configurations emerging at the jet flowing in a channel at different modes have been determined. The type of shock-wave structure and the nature of interaction of the mixing layer of a jet with the wall or reverse flow flowing into the channel from ambient medium determine the appropriate mode. Combination of physical and numerical experiment with bottom pressure calculation according to the developed semi-empirical model have revealed new flow regimes that were not studied earlier.

An experimental study aimed at revealing the possibility of simulation, in a subsonic wind tunnel, of enhanced Reynolds numbers Re^** via modeling a thick flat-plate boundary layer possessing the properties of a Clauser-equilibrium shear flow is reported. We show that turbulators prepared in the form of variable-height cylinders of height h and diameter d = 3 mm and installed in two rows along the normal to the streamlined wall offer rather an efficient means for modification of turbulent boundary layer in solving the problem. In the majority of cases, mean and fluctuating characteristics of the boundary layer exhibit values typical of naturally developing turbulent boundary layers at a distance of 530 cylinder diameters. The profiles of mean velocity with artificially enhanced boundary-layer thickness can be well approximated, in the law-of-the-wall variables, with the well-known distribution of velocities for canonical boundary layer.

Results are presented on visualization of a separated flow behind two kinds of transverse ribs in a channel for a range of Reynolds numbers covering the different stages of laminar-turbulent flow transition. The data was obtained on dynamics of kinematic structure of flow and on evolution of large-scale transverse vortex structures which were generated in the mixing layer during late stages of laminar-turbulent transition. The qualitative estimates were obtained for the vortex generation frequency and velocity of their convective transfer. The features of flow structure were identified for flow behind tested shapes of ribs.

The calculation procedure of the ejector with water-vapor condensation in primary nozzle and in converging chamber is presented. Calculations are performed in a wide range of temperatures of primary and secondary gases. The differences are identified in the properties of gas- and vapor-driven ejectors. Limiting mass rates ratios of gas ejectors are reached by primary temperature increase, but the highest performance of vapor-driven ejectors is realized with the use of saturated vapor.

Stability of the combined flow of liquid film and turbulent gas is studied theoretically for an arbitrary angle between the directions of gas flow and gravity force. The three-dimensional wave flow of the film is described on the basis of integral approach and quasilaminar model of the turbulent gas flow. Increment and phase velocity of waves are calculated for the case of a vertical film and horizontal gas flow depending on the direction of their propagation. According to calculations, the cross gas flow increases the instability area significantly as well as the range of directions for propagation of the fast growing perturbations on the film surface.

The flows of viscous liquid film over the outer surface of a vertical cylinder are examined. Investigation of wave regimes in the case of low flow rates and large cylinder radii is reduced to the analysis of solutions to a nonlinear evolution equation for the film thickness. There are countable numbers of steady-state traveling solution families in the considered model. In turn, most of them are unstable to 2D and 3D perturbations. Thus, evolution of initial perturbations in different ranges of parameter values differs significantly.
Some typical scenarios of perturbation development are presented in this work. Initial perturbations with some symmetries, kept in the process of evolution, are of a particular interest. In these cases, solutions are drawn up to the steady-state traveling solutions with similar symmetry.

The dynamic process of rewetting of the overheated surface by gravitationally falling film of cryogenic liquid was firstly modeled numerically with consideration of local distribution of heat transfer coefficient in the wetting zone along the 2D front. The front shape corresponding to self-organizing regular structures observed in experiments was obtained in the numerical experiment. Evolution of the front shape was studied. It was shown that local motion velocities of different areas of the 2D wetting front differed significantly. Total time of transitional process was determined by the minimal velocity of evaporating liquid boundaries in the front zones between boiling jets. This model allows quantitative determination for the wetting front velocity, variable in time and space, and temperature fields in the heater. Reliability of calculation results was proved by direct comparison with experimental data.

Heat transfer in a sessile liquid droplet was studied with numerical methods. A computer code was developed for solving the problem of convection in an axisymmetric hemispherical droplet and in a spherical layer as well. The problem of establishing an equilibrium state in a droplet was solved using several variables: temperature, stream function, and vorticity. Simulation was performed for droplets of water, ethyl alcohol, and model liquids. Variable parameters: intensity of heat transfer from droplet surface, Rayleigh and Marangoni dimensionless criteria, and the characteristic temperature difference. It was revealed that the curve of convective flow intensity versus heat transfer intensity at droplet surface has a maximum. A dual-vortex structure was obtained in a stationary hemispherical profile of liquid droplet for the case of close values for thermocapillary and thermogravitational forces. Either thermocapillary or thermogravitational vortex might be dominating phenomena in the flow structure.

Superheated water flowing out from high-pressure chamber through short cylindrical and slot channel has been studied experimentally. Relation of vaporization mechanisms in superheated liquid (boiling in single, not interacting centers, intense heterogeneous vaporization, and homogeneous fluctuating nucleation) and respective forms of superheated water jets has been determined. Temperature intervals with transient behavior of boiling have been determined. It is shown that at transient behavior of boiling the amplitude of pulsations of jet parameters increases, and in the spectra of pulsation power, the low-frequency component 1/f appears.

To improve control of the process of nano-powder production in the industrial plant based on electron accelerator, partial pressure of vapors was evaluated at evaporation for different reactions of aluminum, silicon, and titanium oxides. The performed experiments qualitatively proved the correctness of calculations. Besides, influence of water vapors added in gas-carrier on the productivity and average size of the particles of the obtained nano-powder were studied experimentally.

Thermal conductivity of a number of solid solutions of gadolinium and dysprosium sulfides has been studied experimentally within the temperature range 80−400 K. The work offers the data on thermal conductivity coefficient and lattice thermal conductivity of the studied samples. It was found that replacement of gadolinium ions by dysprosium ions leads to significant decrease of the samples' thermal conductivity and changes its temperature dependence character due to the resonance scattering of phonons by paramagnetic ions of dysprosium. Influence of this mechanism of phonon scattering conditions the area of anomalous change observed on the concentration dependence of thermal conductivity coefficient.

On May 6, 2012 Eduard P. Volchkov, the prominent scientist working in the area of thermophysics, Doctor of Technical Sciences, Professor, and Full Member of the Russian Academy of Sciences became 75 years of age.

The article deals with the problems of professional self-determination of the person in the process of pre-university training. The article discusses the concept of self-determination, the conditions for successful realization of this process, philosophical and pedagogical approach to the problem of self-determination and self-development. The article summarizes the features of pre-university training of students in terms of their activity, creativity and readiness for choice, their self-awareness within the future profession

Based on the philosophy of education, there is presented in the article an analysis of intrinsic characteristics of professional educational standards (including the Federal State Educational Standards (FSES-3)) from the positions of opportunity of socialization of the person and the completeness of human existence. It is shown that the competence approach in professional and educational standardization according to Western examples forms not the personality but the labor force on the labor market possessing a set of competences. As a result,there disappear the completeness and prospects of human existence; there takes place deconstruction of personal qualities, world outlooks, the meaning-of-life reference points of the countrys youth.

Traditionally in philosophy experiment is characterized as the category that settles integrity and universality of the human activities, as the unity of knowledge, skill, sense of will, mechanism of social, historical and cultural inheritance. In this article we consider the category of teachers personal experiment in context of different of philosophical tendencies and direcctions, give the determination of teachers personal experiment, define the maintenance and peculiarities of their development, define conditions of forming, sources of development, describe the primary characteristics.

The author considers and analyzes the all-around development of the person which is impossible without persons mastering the culture of physical training. There are analyzedthe issues of healthy lifestyle of the youth. The author considers the following problem: many students do not clearly understand the purposes and objectives of physical education. There are revealed the reasons preventing students going in for sport and followinga healthy way of life. This complicates the process of their adaptation to the specific forms of training in the higher education institution. Therefore, the question is very topical of how to teach higher education students to use regularly various methods and forms of physical training in everyday life.

The paper considers the problem of creating favorable conditions for preserving and revealing the research capabilities of students and faculty in the context of current educational reforms in the Russian universities

In the article,the conceptual and legal bases of resourceand energy saving are considered. A retrospective review of studying this subject in the philosophical and pedagogical literature is carried out. A thesaurus of the main concepts on the subject of resource saving is presented. There is considered the content of the education based on the principles of rational resource consumption and resource saving(on the example of various countries and, in particular, the Russian Federation).

The author examines the specificity of training of urban professions - architects, engineers, builders, urban planning engineers -on the basis ofa methodology of dialectical unity of education and society. Education in the field of urban development must correspond to the objective system of Russian town-forming factors and the existing level of development of social relations.

The authors analyze the ideas of self-development of the man, his self-knowledge, permanency and endlessness of this search in philosophy since the age of antiquity till modern time. Philosophical essence and meaning of personal and professional self-development as the ability of the person to perfect himself in accordance with his individuality is investigated in the article. Thus, there are substantiated the role and place of personal and professional self-development of the cadet, directed on the activity of development of the personal and professionally important qualities.

In the article, the substantiation of the concept of «pedagogical system» is given; the purpose of such pedagogical system as «Training the officers of top qualification» is defined. A special attention is given to the activity motivation during training

In the article, the methods and contents of experimental work on pedagogical training of the teachers of the higher military educational institutions are considered. The experimental work has corroborated reliability of the elaborated criteria and accepted indices which allowed determining the levels of pedagogical training of the teachers of the higher military educational institutions of the Republic of Kazakhstan

In connection with the transition to the new state educational standards of the higher professional education and the reforms being carried out of the military education, the author, on the basis of the analysis of existing system of officers preparation to the professional pedagogic work, offers a model of preparation of officers-teachers to such work. The offered model is based on the personality of the officer-teacher, his professional pedagogic work and the professional-pedagogical competencies of the officer-teacher of the higher military educational institution of Interior Troops of the Ministry of Internal Affairs of Russia.

The author analyzes the content and some problems of military education on modern stage, its main point and role in providing training of the officer,a multi-profile professional. In the article the ways of improvement of the methods of teaching in military educational institutions are investigated, the priority of practical orientation of education is emphasized. On the basis of an analysis of quality of training and upbringing in military educational institutions,eight principal directions are substantiatedin the interests of their improvement. Thus, the main problems of military education and the ways of their solving are considered.

Inthearticle, theproblemsofapplicationofthe modeling method in the educational process in the military higher education institution arediscussed, the foundations of a model of the pedagogical system are considered. Aspecialattentionispaidtotheproblemsofpost-graduate professional training of the teaching personnel of the Armed Forces of Kazakhstan.

The article is devoted to the anniversary of NikolaiMefodievichChurinov, theMember of the International Academy of Noosphere, the Corresponding Member of the International Academy of Higher Education, the Member of the Academy of Social Sciences, the President of the Dissertation Council for Doctoral and Candidate dissertations, the member of the Editorial Board of the Philosophy of Educationjournal, Editor-in-Chief of the Theory and History scientific journal, Doctor of Philosophical Sciences, Professor and the Head of Chair of Philosophy and Social Sciences of M. F. ReshetnevSiberian State Aerospace University.