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Vestnik NSU. Series: Physics. 2013. V8, i 4 |
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Quantum Optics, Quantum Electronics |
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Ayrapetyan V. S., Shirokova T. A., Pasko P. G. The Parametric IR Lasers with High Radiation Efficiency over the Entirerange of Frequency Tuning Computational and experimental studies of the lasing characteristics of IR optical parametric oscillator (OPO) on the
nonlinear crystal LiNbO3 were performed. Implemented outside the cavity ring scheme OPO with replaceable output |
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Radiophysics and Electronics |
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Kuznetsov S. A., Arzhannikov A. V., Thumm М. К. А. Peculiarities of Electromagnetic Waves Diffraction on Regular-Periodic Inductive Metallic Structures We consider the key aspects in electrodynamics of planar metallic microstructures with a regular-periodic topological pattern of the inductive type intended for using as frequency-selective filters in the terahertz range. The consideration is carried out by the example of low- and high-aspect structures with the topology of dipole slots. The full-wave electromagnetic simulator ANSYS HFSS™ is employed to accurately model a spectral response of such structures at different slothole sizes and thicknesses of the bearing metallic layer. These simulations allow one to explain the electrodynamic peculiarities of the similar structures fabricated by the LIGA-technology in the Siberian Synchrotron and Terahertz Radiation Centre. The presented results can be further used when developing the microstructured filters with optimized frequency selective characteristics. |
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High-Energy and Accelerator Physics, Physics of High-Temperature Plasma |
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Shevchenko O. A., Vinokurov N. A. Statistical Theory of the SASE FEL Based on the Two Particle Correlation Function Equation The startup from noise problem in SASE FELs is usually treated in linear approximation. In this case amplification of
initial density fluctuations may be calculated, and averaging over initial conditions may be fulfilled explicitly. In general |
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Shevchenko O. A., Vinokurov N. A. Calculaiton of the SASE FEL Two-Time Correlation Function at the Linear Stage of Amplification The new approach for the SASE radiation properties calculation was proposed recently. It is based on the use of
BBGKY chain of equations, adapted for FEL. In fact, it is the only known logically correct way to describe the SASE |
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Ancharova U. V., Mikhailenko M. A., Sharafutdinov M. R., Tolochko B. P., Bryazgin A. A., Vlasov A. Yu., Korobeynikov M. V., Shtarklev E. A. Effect of Irradiation with Relativistic Electrons on the Synthesis Kinetics of Ni0.75Zn0.25Fe2O4 High-temperature synthesis of nickel-zinc ferrite Ni0.75Zn0.25Fe2O4 has been carried out under heating in high temperature chamber and by radiation-thermal treatment under influence of intensive electron beam. It is shown that after irradiation in the temperature range 600-1000?C there is a significant increase in the reaction rate and product shrinkage, ceramics grain size uniformity also increases. |
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Physics of Field, Neutral and Ionized Gases |
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Bobarykina T. A., Chirkashenko V. F. A Shock Wave Parameters Control by Its Interaction with the Low Density Gas Layer Wind tunnel research with a supersonic (M = 2) flow (~ 0.1 m in diameter) and the numerical simulations using the two-dimensional Navier – Stokes equations were conducted to substantiate conditions sufficient to substantially reduce a shock wave intensity at its interaction with a layer of low-density gas. The results of experimental studies of the interaction of a shock wave with a gas layer heated by the combustion of hydrogen and air are shown. Numerical simulations resulted in data about the efficiency of the impact thermal layer/shock wave in a wind range of determining parameters. Also the parameters of the flow in the thermal layer providing substantial reduction in the intensity of the shock wave were determined. |
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Gaponov S. A., Terekhova N. M. Modeling of External Pressure Gradient Influence on the Stability of Disturbances in the Boundary Layers of Compressed Gas This work continues the research on modeling of passive methods of management of flow regimes in the boundary layers of compressed gas. Authors consider the influence of pressure gradient on the evolution of perturbations of different nature. For low Mach number M = 2 increase in pressure contributes to an earlier transition of laminar to turbulent flow, and, on the contrary, drop in the pressure leads to a prolongation of the transition to turbulence. For high Mach number M = 5.35 found that the acoustic disturbances exhibit a very high dependence on the sign and magnitude of the external gradient, with a favorable gradient of the critical Reynolds number becomes smaller than the vortex disturbances, and at worst – boundary layer is destabilized directly on the leading edge. |
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Vinokurov A. P., Shtork S. I., Alekseenko S. V. Study of Unsteady Vortical Structures in Axisymmetric Hydrodynamic Chamber The paper is devoted to experimental and numerical investigation of unsteady vortical processes in the isothermal model of axisymmetric vortex burner. Obtained characteristics of precessing vortex core (PVC) show the dependences of PVC`s frequency on flowrate, swirl number and nozzle`s diameter. Pressure drops inside the chamber also have been measured. Laser Doppler Anemometer (LDA) has been used to explore spatial distribution of mean axial velocity. Numerical simulation has been carried out by using computational fluid dynamic (CFD) program Adapco Star-CCM+. Detached Eddy Simulation approach and Spalart-Allmaras model have been used for calculating the flow. Results of comparison of experimental and numerical data have shown validity of used numerical method. Combination of experimental and mathematical modeling gives the possibility of obtaining detailed information representing comprehensive description of spatially complex unsteady flow with the PVC. |
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Zapryagaev V. I., Kavun I. N., Kundasev S. G. An Experimental and Numerical Study of a Supersonic Overexpanded Jet Gas-Dynamic Structure Experimental data about the structure of the supersonic overexpanded jet (Ma=3, n=0.58) is obtained. This data is intended for verification of numerical calculation results. Main factors influencing on the precision of experimental data are shown. Experimental results are supplemented with numerical simulation performed with program package ANSYS Fluent. Differences between experimental and numerical data are analyzed. |
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Khachikian A. A., Bunev V. A., Bolshova T. A., Babkin V. S. Laminar Burning Velocities of
Methanol, Ethanol and Numerical Research of Processes of Spontaneous Ignition and Processes of spontaneous ignition and propagation of a flat laminar flame in ethanol mixes with air investigated by numerical methods. It is shown that in rich mixes in a flame and at spontaneous ignition superadiabatic temperatures develop. Faster process of formation of water appears also more productive in a thermal emission and temperature increase, than slower processes of formation of CO and CO2. Presence of superadiabatic temperatures stabilizes burning of rich mixes of ethanol of subcritical composition. |
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Zamuraev V. P., Kalinina A. P. Numerical and Analytical Estimation of Parameters of Pulsed Energy Sources which Do not Lead to Locking of Supersonic Flow in Channels of Variable Section In this paper the pulse energy supply into the channel of variable cross section was studied. The approximate formulas were obtained for the value of the input energy, corresponding to the maximal distance which the shock wave from a pulsed power source reached upstream, as well as full power, energy supply period corresponding to the conditions of closing the channel. The applicability of the analytical relationships is confirmed by numerical calculations based on the Euler equations in a quasi one-dimensional approximation. |
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Dobroselskiy K. G. Research Methodology of Cross-Flow Cylinder Pipe Hydrodynamical Experimental setup (hydrodynamic pipe) for the study of turbulent flows has been upgraded. Test experiments with a
cross-flow around a cylinder have been carried out. Using the method of flow visualization PIV (Particle Image |
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Computer Science, Information-Communication Technologies |
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Morozov B. B., Dolgovesov B. S., Mazurok B. S., Gorodilov M. A. Features of Building Systems Based on Visualization of Distributed Multimedia Environment An approach to the development of technical solutions for the creating of a real-time Distributed Multimedia Virtual Environment is described. The main objective of the environment - control the formation and delivery of multimedia content from multiple sources to multiple recipients. |
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