Quantum Optics, Quantum Electronics |
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ÁBrazhnikov D. V., Bonert A. E., Goncharov A. N., Taichenachev A. V., Tumaikin A. M.,
Yudin V. I., Basalaev M. Yu., Ilenkov R. Ya., Shilov A. M. Study OF A Possibility of Deep Theoretical analysis of sub-Doppler laser cooling of 24Mg atoms using 3^3P2 > 3^3D3 transition in the field of two counterpropagating light waves with opposite circular polarizations is presented. The standard semi-classical approach based on the Fokker-Plank equation is exploited for numerical modeling of laser cooling. The problem is solved out of limits of slow atom approximation and for arbitrary light intensity. The dependences of light force and diffusion on an atomic velocity are studied for various frequency detuning and Rabi frequency. Also, to obtain optimal parameters of laser cooling, the atomic velocity distributions are investigated for various conditions and the dependence of average atomic kinetic energy on the light field intensity and frequency detuning is calculated. In the case of strong field a multi-spike velocity distribution profile is observed. It results from various nonlinear effects accompany absorption of laser photons by atoms. In conclusion we make additional recommendations to increase atoms in metastable state 3^3P2, what is necessary for effective laser cooling. |
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E. V. Baklanov, A. A. Kurbatov INCREASING OF THE SIGNAL-TO-NOISE RATIO IN PRECISION SPECTROSCOPY Is considered the possibility of increasing the signal / noise ratio in one of the main methods of laser spectroscopy
without Doppler broadening – the method of saturated absorption. The colliding beam of laser radiation in a multimode |
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Kuznetsov S. A., Gentselev A. N., Goldenberg B. G., Kondratyev V. I., Arzhannikov A. V., Thumm Ì. Ê. À., Zelinsky A. G. Elaboration of Microstructured Subterahertz Filters via LIGA Technology and Investigation of Their Selective Properties We discuss the peculiar features of the LIGA-technology methods elaborated in the Siberian Synchrotron and Terahertz
Radiation Centre (SSTRC, BINP SB RAS) and applied for producing quasi-optical subterahertz filters based on |
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Belikov O. V., Veremeenko V. F., Kozak V. R., Medvedko A. S., Kuper E. A. CEAC Controllers Family for Control of Power Supplies of Accelerator Facilities Accelerator facilities includes hundreds electromagnets which should be powered by power supplies. These power supplies should be tune in wide range with high accuracy. Here are described a device set (CEAC family) for this application. These controllers are incorporated in end equipment and provide required parameters. Balance between general purpose functions and accelerator specified functions allows to minimize number of device models and to extend application field. Power supply controllers are connected with control network by CANbus line. |
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Bekhtenev E. A., Karpov G. V. Automated Stand for Measurements of Electrostatic Beam Position Monitors Parameters A stand for measurements of the electrostatic beam position monitors (BPM) parameters is described. BPM parameters are measured with help of movable antenna modeling the charged-particle beam. Moving of the antenna is performed on two orthogonal directions with help of stepping motors. Full automation facilitates the measurements of BPM coordinate grid with high position resolution. Stand electronics allows BPM parameters measurements with high accuracy. Measurements at the stand performed with BPMs have demonstrated repeatability of the measurements results at level of 10–15 microns what satisfies all requirements to stand. The stand described in the paper was used for quality control of electrostatic BPM production. |
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Physics of Field, Neutral and Ionized Gases |
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Zverkov I. D., Kozlov V. V., Kryukov A. V. Flow Feature Near Unswept and Swept Finit Span Wing with Smooth and Wavy Surface at Stall Angle of Attack Incompressible flow feature at near stall angle off attack on classical and wavy surface wing with aspect ratio ? = 3,7 at Reynolds number 1,5 *10^5 was investigated. Such kinds of the wings at the same Reynolds number are employing on micro air vehicle. Vitality of the small aircraft at near ground atmospheric condition flight depends from predictable wing behavior at near stall angle of attack. Separation and attached flow structure at lee surface of wavy and classical wing was shown by oil-film visualization at sweep and no sweep angle condition. It was shown the wavy wing at no sweep condition has the stall angle of attack lager than classical one. At post-stall angle of attack ? = 9? for classical wing sweep angle increasing from 15? to 45? results to changing from separation flow regime to attached one. On wavy wing at the same angle of attack and sweep angle from 0? to 45? the attached flow is observed only. In practice, this means that micro air vehicle will easy controlling by automatic system and will fall in stall regime rarely. |
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Dulin V. M., Chikishev L. M., Markovich D. M., Hanjalic K. Modification of Swirling Jet Flow by Premixed Combustion Effect of combustion of propane-air mixture in a weakly and strongly swirling jet was studied. The rate of swirl was
classified in terms of the absence / presence of a stable recirculation zone in the non-reacting jet flow. Sequences of the |
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Podryabinkin E. V., Rudyak V. Ya. Modeling of Turbulent Flows through the Annular Channel with Eccentricity and Rotating Inner Cilinder In this paper fully developed turbulent flows of Newtonian fluid in cylindrical annulus with eccentricity and rotating inner cylinder has been systematically studied. Modeling has been performed on the base of Menter Shear Transport model of turbulence in a wide range of Reynolds numbers, eccentricity, and radii ratio. As the result dependencies of flow field and pressure drop along the channel on geometrical and flow parameters have been found. It was shown that flow characteristics and dependence of the pressure drop are determined by which flow axial or rotational dominates and caused generation of turbulence. When rotational flow dominates the dependence of the pressure drop is almost linear. When axial flow dominates rotation practically has no impact on the pressure drop in concentric annulus. Appearance of the reverse flow in eccentric channel has a major impact on the pressure drop. In case when rotational flow dominates, appearance of the reverse flow is accompanied by threshold flow restructuring at some critical value of eccentricity. A correlation for determination of the pressure drop in various regimes has been developed for the case of concentric annulus. |
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Yakovenko S. N. Budget of Equations for Reynolds Stresses in a Turbulent Patch Arising from Internal Wave Breaking Results of the direct numerical simulations are used to obtain statistical moments in a quasi-steady turbulent patch arising in a stably stratified flow above an obstacle after internal wave breaking. Temporal evolution and spatial behavior of the Reynolds-stress tensor components and budgets of the Reynolds-stress transport equations have been studied. Such an analysis is helpful to explore the turbulent patch and its energetic characteristics by means of statistical moments, to examine closure hypotheses in turbulence models, and to evaluate geophysically important quantites. In particular, the calculated global value of the mixing efficiency is about 0.2 as in oceanic applications. Moreover, simple algebraic relations are proposed between the turbulent kinetic energy and its dissipation rate. In the Reynolds stress tensor equation, the pressure-strain correlation term provides the redistribution of the normal stress components according to the linear returntoisotropy approximation, whereas the dissipation tensor roughly follows the local-isotropy assumption. |
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Aulchenko S. M., Zamuraev V. P., Kalinina A. P. Criterial Analysis of Nonlinear Regimes of Transonic Flow around the Airfoils with a Pulse-Periodic Source of Energy The paper summarizes our data regarding the energy controlling of the transonic flow. The criterial analysis of the regimes of flow which is formed around the airfoils with an external pulse-periodic energy supply was performed. We selected four criteria, which belong to the class of criteria homochronicity. They are determined by the relations between the period of the energy supply, the rate of gas flow, the velocity of propagation of small disturbances and distances from the beginning or the end zone of energy supply to the position of the closing shock in the undisturbed flow, or the size of the zone of energy. It was shown that the conditions for the forming of the nonlinear regime can be described in terms of the entered criteria of homochronicity. We also obtained estimates for the minimum energy at which the effect of nonlinear interaction is possible, as well as the time of formation of the periodic mode. It was found that the nonlinear effect predominantly has gas-dynamic nature. It was shown that the results of numerical modeling are in agreement with the criterial estimates. |
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Solid-State and Semiconductor Physics, Physics of Nanostructures |
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Bardakhanov S. P., Vikulina L. S., Lysenko V. I., Nomoev A. V., Poluyanov S. A., Tuzikov F. V. Analysis of Nanopowders by Small-Angle X-Ray Scattering Method’s The possibility of application of small-angle X-ray scattering (SAXS) for nanopowders analysis was studied. The research
for eight silica powders (including four powders obtained by the authors with help of electron accelerator) was |
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Rozhin A. A., Kochubei S. A., Rubtsova N. N., Shamirzaev T. S., Kovalyov A. A., Semyagin B. R., Preobrazhenskii V. V., Putyato M. A., Buganov O. V., Tikhomirov S. A. Ultraviolet Radiation Action onto Nanostructures with Quantum Wells GaAs/AlGaAs Optical properties modification of semiconductor heterostructure with quantum wells GaAs/AlGaAs by the ultraviolet (UV) radiation was investigated in the range of energy density of 0 – 500 mJ/cm2. It was shown that hotoluminescence signal amplitude decreases with an increase of UV energy density; this dependence revealed threshold nature with the threshold value about 100 mJ/cm2 – in agreement with other results on laser formation of the point defects in GaAs. Reflectivity kinetics of the sample detected at the probe radiation wavelength corresponding to the photoluminescence line center showed an increase of electron-hole recombination rate with growth of UV energy density. Sharp focusing of UV laser radiation led to a plume formation over the sample surface; spectrum of the plume contained neutral gallium atoms doublet at wavelengths of 403 íì and 417 nm. |
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Berdnikov V. S., Kudryavtseva M. A. Simulation of the Conjugate Heat Trasfer on the Process Incipient State in a Bridgman Method Numerically the conjugate convective heat transfer in a flat-bottomed graphite crucible at a stage previous an onset
of solidification of a silicon melt in a vertical variant of a Bridgman method is researched. The finite element method on |
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Chemical, Biological and Medical Physics |
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Kalgin I. V., Chekmarev S. F. Self-Similarity of Protein Folding Flows The problem of how a protein folds into its functional (native) state is one of the central problems of molecular biology,
which attracts the attention of researchers from biology, physics and chemistry for many years. Of particular interest |
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Computer Science, Information-Communication Technologies |
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Kitushin G. G. Some Examples of the Third Order Filters with Constant Input Impedance Synthesis The article is devoted to filter with constant impedance synthesis. The filter consists of appropriate ladder networks shunt connection. The third order Chebyshev filters and a filter with nonclassical transfer function are considered as examples. |
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