Quantum Optics, Quantum Electronics |
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Benimetskiy F. A., Plekhanov A. I. Optical Gain Coefficient Measurement of Colloidal Solution of Spasers Optical gain coefficient of colloidal solution of spasers was measured by the variable stripe length method, where the intensity of the amplified spontaneous emission from the sample edge is measured as a function of excited volume. Spasers consist of gold core-silica (porous) shell nanoparticles penetrated with fluorescein. Under these conditions, we observed the exponential growth and narrowing of line and directivity of stimulated emission. The obtained optical gain coefficient of spaser colloids in fluorescein solution in ethanol is g = 16,2 cm–1. Separately, fluorescein solution in ethanol had g = 3,7 cm–1. |
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Radiophysics and Electronics |
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Senkov D. V., Pureskin D. N., Medvedko A. S. The Based on Digital Signal Processor Power Source With Reversible Output Synchronous Rectifier There are the structure and control algorithms 10kW power source with 25 kHz converter and output synchronous rectifier shown in the article. The output voltage or current of power source has controlled waveform with 1 kHz maximal frequency. The output voltage is galvanically isolated from mains. The source design allows using the load’s energy recuperation in the power converter storage capacitor and soft switching in the synchronous rectifier. The article shows the application of power source as 400 Hz waveform regulated sinusoidal voltage generator. |
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Physics of Field, Neutral and Ionized Gases |
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Gaponov S. A., Semenov A. N. Influence the Direction of Blowing Gas through a Porous Surface on the Stability of the Supersonic Boundary Layer In the paper the influence of the gas blowing direction through a porous surface on the supersonic boundary layer stability is investigated theoretically, using the classical method of elementary waves and the evolutionary method at Mach number M = 2. It was found that with decreasing of the gas injection angle to the plane plate the boundary layer stability was improved and the tangential blowing effect on the boundary layer stability is little in a comparison with the case of a boundary layer without mass exchange. |
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A. G. Shmakov, Grek G. R., Kozlov V. V., Korobeinichev O. P., Litvinenko Yu. A. Different Conditions of the Round Hydrogen Jets Diffusion Combustion in Air The purpose of this work is experimental study of diffusion combustion of the round hydrogen microjets with different nozzle diameter. The new phenomenon is revealed during combustion of a hydrogen microjet, which we have named «bottleneck». The special attention has been given to research of characteristics of the «bottleneck» development and its role during of a hydrogen round microjet combustion. It is shown, that «bottleneck» represents the closed spherical area of the hydrogen with air mixture combustion in a jet near-field. The «bottleneck» area is closed by a powerful density gradient. It is found, that the laminar hydrogen jet in this area overcomes a density gradient of gas, becomes turbulent and combustion process is accompanied both a turbulent jet, and a turbulent flame further downstream evolution. It is shown, that the spatial size of a «bottleneck» decreases with growth of a jet velocity. |
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Grek G. R., Katasonov M. M., Kozlov V. V., Litvinenko Yu. A. Diffusion Hydrogen Microjet Combustion (Round Bevelled Nozzle) The purpose of this work is experimental study of diffusion combustion of the round hydrogen microjet at the 45° bevelled nozzle. The new phenomenon is revealed during combustion of a given hydrogen microjet, which we have named «bottleneck», as well as in a situation of the round and plane microjet combustion. The special attention has been given to research of characteristics of the «bottleneck» development and its role during of a hydrogen round microjet combustion. It is shown, that «bottleneck» represents the closed spherical area of the hydrogen with air mixture combustion in a jet near-field. The «bottleneck» area is closed by a powerful density gradient. It is found, that the laminar hydrogen jet in this area overcomes a density gradient of gas, becomes turbulent and combustion process is accompanied both a turbulent jet, and a turbulent flame further downstream evolution. It is shown, that the spatial size of a «bottleneck» decreases with growth of a jet velocity. It is found, that shadow patterns of the microjet combustion obtained for two shooting positions (normal and side view to the bevelled nozzle) were identical. |
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Litvinenko Yu. A., Grek G. R., Kozlov V. V., Korobeinichev O. P., Shmakov A. G. Structure of the Attached Flame during Diffusion Hydrogen Microjet Combustion (Slotted Nozzle) The purpose of this work is experimental study of diffusion combustion of the plane hydrogen microjet with different slotted nozzle dimensions. The new phenomenon is revealed during combustion of a plane hydrogen microjet, which we have named «bottleneck», as well as in a situation of a round microjet combustion. The special attention has been given to research of characteristics of the «bottleneck» development and its role during of a hydrogen plane icrojet combustion. It is shown, that «bottleneck» represents the closed spherical area of the hydrogen with air mixture combustion in a jet near-field. The «bottleneck» area is closed by a powerful density gradient. It is found, that the laminar hydrogen jet in this area overcomes a density gradient of gas, becomes turbulent and combustion process is accompanied both a turbulent jet, and a turbulent flame further downstream evolution. It is shown, that the spatial size of a «bottleneck» decreases with growth of a jet velocity. It is found, that «bottleneck» does not arise in case of the big nozzle lengthening (l/h > 10) |
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Litvinenko Ì. V., Litvinenko Yu. À., Vikhorev V. V., Êîzlov G. V. Influence of Acoustic Fluctuations on the Round Jet, Formed in Curved Channel The results of experimental investigations on the effect of the transverse acoustic fluctuations for subsonic round jet formed in curved channel (d = 20; 9; 1.5 mm) are presented. Using laser – smoke visualization the jet instant picture sections were received, which showed the presence of two modes jets instabilities – Kelvin – Helmholtz vortices and Dean vortices and their interaction. The influence of the acoustic excitation frequencies on the jets are shown, in particular on a wavelength of Kelvin – Helmholtz instability. The picture of the diffusion combustion of propane jet with a nozzle diameter of d = 1,5 mm without acoustic excitation and with acoustic excitation are compared. It has been observed that the diffusion flame combustion of propane is subject to transformation by the action of the acoustic field and developing instabilities in the jet. |
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Skripkin S. G., Tsoy M. A., Shtork S. I. Experimental Investigation of Double Precessing Vortex Rope Forming in Draft Tube Models This work is devoted to the experimental research of the flow structure in draft tube models of hydro turbines. Precessing vortex core was formed using fixed swirler in a flow such as observed in natural hydro turbines under off-design conditions. In laboratory conditions it has been able to find the effect of the transition between single- and double- vortex rope. Their frequency characteristics have been measured in the range of Reynolds numbers 5·104–5·105. Based on the analysis of data high-speed shooting the mechanism of complete transition between single and double vortex modes was investigated in detail. The investigation of this phenomenon is of particular interest for the design and operation of hydraulic turbine equipment due to off-design pressure pulsations with sudden changes in frequency and amplitude in a flow occurring. |
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Solid-State and Semiconductor Physics, Physics of Nanostructures |
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Korshunov M. M., Togushova Yu. N. Interplay of Superconductivity and Magnetic Excitations in Multiorbital Systems We have considered the impact of the nontrivial superconducting order parameter on the magnetic susceptibility within the multiorbital model for the iron-based materials. The formation of the spin-resonance peak is demonstrated and its connection to the experimental data on the inelastic neutron scattering is discussed. |
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Computer science, information-communication technologies |
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Gorodilov M. A., Dolgovesov B. S., Khramtsov I. D., Radostev A. H. Features of Multi-Screen Displayof Distributed Multimedia Data This article is devoted to solving some of the issues of distributed multimedia data display on large screens. In particular, we consider the problem of synchronization of the process of parallel rendering and output of video fragments to the appropriate modules of multiscreen display systems. Proposed synchronization algorithm and its implementation using graphics accelerators, provides visual continuity of dynamic scenes when displayed on a multiscreen. The problems of managing distributed input data stream for multiscreen display are considered. |
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