Vestnik NSU. Series: Physics. 2013. V8, i 1

Quantum Optics, Quantum Electronics

Gerasimov V. V., Zhizhin G. N., Knyazev B. A., Kotelnikov I. A., Nikitin A. К., Cherkassky V. S. Study of Diffraction of Surface Plasmon Polaritons at the Rectangular Edge of a Metall-
Dielectric Interface in the Terahertz Region

Surface plasmon polaritons diffraction at the rectangular edge of a plane gold-dielectric interface was studied using monochromatic terahertz radiation of Novosibirsk free electron laser. Experimental results were compared with the exact solution of the two dimensional diffraction problem. For short distances from the sample edge experimental data reasonably agreed with theory. The field intensity distribution beyond the edge is not symmetrical regarding to the sample surface and extends mainly in the upper hemisphere. In the far zone the electromagnetic field forms a freely-propagating wave which has Lorentzian profile with the divergence depended on the surface impedance. The propagation length of surface plasmon polaritons along bare gold and gold covered with a submicron ZnS layers were measured and amounted to tens of millimeters.

6

Alekseev D. V., Travin A. V. Measurement of Temperature Distribution on Mineral Surface during Argon-Argon Laser Step Heating Dating

New pyrometric method of temperature distribution measurement on surface of natural mineral during laser 40Ar/39Ar dating has been devised. Peculiarity of this method is that it is relatively simple and does not require in availability of information about under test object absorption ability. It is very important during measurement of temperature distribution on surface of natural mineral. Proposed method includes forming of two digital pictures of sample in one frequency only, using of proposed method in conventional laser complexes intended for 40Ar/39Ar dating does not require large additional technical expense. Special program on the basis of platform Framework 4.0 has been devised for data processing automatization. Temperature field in several geological samples has been researched using method proposed. Data obtained indicates that temperature distribution in some of the samples during laser stepwise dating is sufficiently heterogeneous. Nonuniformity of temperature distribution can result in appearance do not taking into account inaccuracy in age value, that larger of analytical inaccuracy in few time. Thus, data obtained indicates that control of temperature distribution homogeneity during laser 40Ar/39Ar stepwise dating is necessary condition of accuracy dating result.

16

Radiophysics and Electronics

Kuzikov S. V., Peskov N. Yu., Plotkin M. E. Open Bragg Cavity with Gaussian Wavebeam for Free Electron Maser of Centimeter Wavelength Range

This paper describes a highly selective electromagnetic cavity for a 30 GHz free electron maser (FEM). The cavity consists of two Bragg reflectors with overlapping reflection bands. Reflectors have been synthesized with the help of
coupled waves method. For the sake of mode selectivity reflectors are separated by a gap which is wide in the wavelength scale. The operating mode in the interspace between the reflectors represents a Gaussian wavebeam of small diameter, so that its field is detached from the cavity walls, and the loss of radiation through the gap is negligible. At the same time, spurious modes undergo strong diffraction losses through the gap due to different transverse structure of the field. In the calculations, the Q-factor of the operating mode was shown to be at least three times as big as the Q-factors of all spurious modes within the Bragg band. The tested stainless still cavity contained a cylindrical middle-section covered with the absorbing material alsifer to emulate the gap. In low-power tests, the only high-Q mode was observed in the Bragg band, with the frequency of that mode corresponding to the calculated frequency of the operating mode. High-power testing of the cavity is planned in the nearest future.

24

Arbuzov V. S., Gorniker E. I., Kozyrev E. V., Kondakov A. A., Petrov V. M., Pilan A. M., Tribendis A. G. Feeding System of a High-Frequency Accelerating Cavities of the Novosibirsk
Microtron-Recovery Unit for the FEL. Divider of a High CW Power on the Basis of a Rectangular Waveguide

The article is devoted to the system of the Radio Frequency power transfer and distribution between accelerating cavities of the ERL for FEL of the Siberian center of SR and THz Radiation, SB RAS, Novosibirsk. The system of dividing is built on the basis of a rectangular waveguide, associated with each cavity of a coaxial line by the coaxial-to-waveguide adapter (CWA). It is shown that under a certain choice of waveguide sizes and CWA, the equivalent circuit of the CWA can be represented by a current source. The analysis of the properties of such a system has been carried out and shown its advantages. Also it is discussed the experimental results and the experience of the operation of the device. The article presents the basic design parameters of a waveguide divider 600 kW of continuous power, running at a frequency of 180.4 MHz.

32

Physics of Field, Neutral and Ionized Gases

Gubanov D. A., Zapryagaev V. I., Kiselev N. P. Flow Stucture of Supersonic Underexpanded Jet with Microjets Injection

Experimental and numerical study of transversal microjets injection influence on the supersonic underexpanded jet flow structure has been performed. Data of measurements and calculation have acceptable agreement.
Interaction of microjets with main supersonic jet sets to a decrease of an initial gasdynamic region. Microjets lead to a longitudinal streamwise vortices generation and a mushroom-like flow structures create on an external jet mixing layer. Dissipation of longitudinal streamwise vortices was observed at the second jet cell. Complex gasdynamic flow structure of the supersonic underexpanded jet interacting with supersonic microjets has been studied for the first time. This structure contains system of complex chock waves and expansion waves spreading from the position of the impact microjets/main jet localization place. Future of interaction process a chock-wave structure of main jet with additional shock waves has been studied.

44

Abdurakipov S. S., Dulin V. M., Markovich D. M. Experimental Investigation of Coherent Structure Dynamics in a Submerged Forced Jet

The present work investigates the dynamics of coherent structures, including their scales and intensity, in an initial region of a submerged round forced jet by a Particle Image Velocimetry (PIV) technique for measurements of instantaneous velocity fields and statistical analysis tool Dynamic Mode Decomposition (DMD). The PIV measurements were carried out with 1,1 kHz acquisition rate. Application of DMD to the measured set of the velocity fields provided information about dominant frequencies, contained in DMD spectrum, of velocity fluctuations in different flow regions and about scales of the corresponding spatial coherent structures, contained in DMD modes. Additional calculations of time-spectra from turbulent fluctuations showed good agreement between frequencies of the main harmonics and characteristic frequencies of the dominant dynamic modes. Superposition of relevant DMD modes approximately described nonlinear interaction of coherent structures: vortex formation, their quasi-periodic pairing with modulation amplitude of generated harmonics.

56

Anisimov M. P., Petrova-Bogdanova O. O. Eutectic and Peritectic Lines for Diagrams of Quasi Equilibria of Binary Systems with Partially Soluble Components

Topologies of the nucleation rate surfaces over phase equilibria diagrams with eutectic and peritectic points are constructed schematically. Theoretical methods to obtain the topology of these surfaces are not yet available. Individual eutectic and peritectic points, empirically observed previously in non-equilibrium conditions, are following as particular cases of the common results of the present paper. It is shown that there are lines of eutectic and peritectic compositions in general, depending on the mother phase invasion depth into the region of the coupled phase equilibria.

65

Stankus S. V., Khairulin R. A., Martynets V. G., Molorodov Yu. I. Density of Perfluorohexane near the Evaporation Critical Point

The density of n-perfluorohexane along the liquid-vapour coexistence curve has been studied by a gamma-ray attenuation technique over the temperature range from 293.83 to 449.18 K. The critical temperature 449.22 ? 0.05 K, the density 613.8 ? 2 kg/m3, and the critical exponent of coexistence curve 0.349 ? 0.005 were determined. The approximation equations of the temperature dependence of the liquid and vapor phases density were obtained. The results were compared with the data available in the literature. The influence of hydrostatic effect due to the high compressibility of the substance in the vicinity of the vaporization critical point was observed.

73

Kornilov V. I., Boiko A. V. Simulation of Thick Turbulent Boundary Layer via Jet Array

Experimental studies directed to qualify the potential of simulation of an equilibrium (by Klauser) thick incompressible turbulent boundary layer on a flat plate of limited length with the help of an array of jets were carried out. It is shown
that in the range of flow parameters and the mass flow rates of blowing under consideration the air jets through some rows of the holes with different diameter increase substantially the thickness of turbulent boundary layer within a comparatively small distance of the blowing region. In most cases studied, the mean and fluctuating characteristics of the boundary layer reach values specific for naturally developed turbulent boundary layer at downstream distances of about 22 thickness of regular boundary layer. Mean velocity profiles in the logarithmic part of the artificially thickened boundary layer are described by the law-of-the-wall variables with a good accuracy and generalized by a single dependence with the help of empiric velocity scale for the outer region. Disturbance characteristics of the flow are also close to those in the canonic boundary layer. However, as the blowing intensity grows, a systematic deviation of the disturbance streamwise velocity from the canonic values is observed, which indicates the limitation of the present approach and points out the need of further refinement of the method of simulation under consideration.

78

Bardakhanov S. P., Zav’yalov A. P., Lygdenov V. C., Lysenko V. I., Skiba S. S., Nomoev A. V., Manakov A. Yu., Syzrantsev V. V., Romanov N. А., Kalashnikov S. V., Trufanov D. Yu.
Synthesis of Hydrophobic Silica Nanopowders

The technique of receiving of nano-silica nanopowders, consisting of nanoparticles with the known size, form, internal and surface structure and physicochemical properties was developed. The degree of hydrophilicity of those powders was determined. The method of the surface modification (hydrophobization) of the received nanoparticles was carried out and was optimized. Replacement of surface OH-groups on the CH3-group was produced by blowing SiCl2(CH3)2 vapor over the modified powders surface. The carbon content of the modified powders reached 3.2 %. The comparison of the hydrophobization process for the nanopowders received by two different origins was carried out. It was shown that the surface modification of Aerosil powders is faster than Tarkosil ones at similar hydrophilicity degree. Also hydrophobiс Aerosil contains more amount of carbon was cleared (up to 5,9 %). The complete replacement of OH-groups on the organic groups on the surface of powders was showed by IR spectroscopy. The representation of the organic groups by several combinations of fragments, rather than just the CH3 was showed.

92

Lysenko V. I., Gorev V. N., Litvinenko Yu. A., Bardakhanov S. P. Synthesis and Properties of Ceramics from Ferric Oxide Nanopowder

Possibilities of receiving ceramics from the nanodisperse ferric oxide (II, III) powder are investigated. In a hot pressing facility (by Spark Plasma Sintering method) the ceramics with fine-grained (about 1 micron and less) structure made. Structure of the received ceramics is investigated by the method of scanning electronic microscopy. Radiographic examination of initial nanopowder and the received ceramics is also carried out. If in the phase relation the initial powder and the ceramics sintered at 800 оС are magnetite Fe3O4 (75-1610), the ceramics sintered at 900 оС – Fe3O4 (75-33), and at 1200оС the diffraction picture of a mixture of two phases – a iron protoxide FeO (46-1312) phase and a metal Fe (6-696) phase – took place. Microhardness of the ceramics was 8 GPa, ultimate compression strength – 0,8 GPa. Thereby availability of use of the SPS method is shown.

99

Solid-State and Semiconductor Physics, Physics of Nanostructures

Khairulin R. A., Abdullaev R. N., Stankus S. V. The Density of Ternary Bismuth–Indium–Tin Alloy of Eutectic Composition in the Liquid State and in the Region of Melting-Crystallization

The temperature dependence of the density of liquid bismuth–indium–tin alloy of eutectic composition (57.20 wt. % Bi; 24.79 wt. % In; 18.01 wt. % Sn) has been investigated using gamma-ray attenuation technique at temperatures from liquidus line to 950 K. The density change during solid–liquid transition has been measured. It has been found that the behavior of the volume properties of the melt is described quite well by the laws of ideal solution.

104

Аnisimov А. G., Bardakhanov S. P., Zav’yalov А. P., Zobov К. V., Lysenko V. I., Mali V. I., Trufanov D. Yu. Influence of Sintering on the Structure and Properties of Ceramics from Silica Nanopowders

In this paper the ceramics obtained from various silica powders investigated. Two different methods for ceramics receiving (with consecutive pressing and sintering, and the method of hot-pressing (spark plasma sintering)) were tested. For ceramics obtained by different methods the microhardness, ultimate compression strength and grain size were compared. At a classical method of powders sintering the microhardness and durability growth is observed at reduction of the initial particles size though the observed size of grains in ceramics is approximately identical for all types of powders. It is received that vitrification of samples of ceramics created by the SPS method, happens at much smaller temperature (1100°C), than the corresponding temperature at consecutive operations of pressing and sintering (1550°C). Values of microhardness of the ceramics received by two various methods, were similar (~ 2 GPa). Ultimate compression strength value (0,25 GPa) for the samples received by a method of spark plasma sintering, only slightly exceeds the value of ultimate compression strength for the samples created in the traditional way (0,23 GPa). If at consecutive operations of pressing and sintering the ceramics with a micron size of grain turns out, at the SPS method the grains of received ceramics have the size about 300 nm. It speaks about prospects of nanopowders sintering by the method of spark plasma sintering at which nanostructural parameters of powder in the consolidated material remain.

107

Chemical, Biological and Medical Physics

Lomzov A. A., Ivanova K. A., Pyshnaya I. A., Dmitrienko E. V., Pyshnyi D. V. A Comparative Study of the Influence of Aquaous 2,2,2-Trifluoroethanol and Ethanol on the Structural
Organization, the Kinetic and Thermodynamic Properties of Oligodeoxyribonucleotides Intermolecular Complex Formation

A comparative study of the structural organization, thermodynamic and kinetic properties of the oligodeoxynucleotides complexes formation in the presence of 2,2,2-trifluoroethanol and ethanol in aqueous solution (volume fraction
of alcohol 0 to 50 %) was performed. No significant changes in the circular dichroism spectra of oligonucleotides and their complexes at the adding of 50 % v/v alcohol into a solution, was observed, and they retain the profile typical for
B-form DNA. The study of the thermal stability of DNA duplexes showed that the increase in the volume fraction of ethanol in the aqueous solution up to 50 % results in a linear decrease in the melting temperature of the intermolecular DNA complexes. In the case of the 2,2,2-trifluoroethanol we observed atypical dependence of thermal stability of DNA duplexes on the fraction of the fluorine-containing co-solvent. Increasing the alcohol fraction from 0 to 20% v/v led to a linear decrease of the melting point of the complex. A further increase in the volume fraction of alcohol (up to 50 %) did not change the thermal stability of the duplexes. It was shown, that the destabilizing effect of the two co-solvents is due to the increase of the dissociation rate constant of the complex and has mainly entropic nature. On the example of oligonucleotides complexes of 8, 12, 15 and 20 base pairs length the possibility of prediction DNA duplexes thermal stability was shown. A model taking into account the change of a number solvent molecules interacting with nucleic acids at the duplex formation in aqueous ethanol (50 % v/v) or trifluoroethanol (20 % v/v) was applied. An accuracy of melting temperature prediction was 1.3 and 0.6 degrees. Using this model, we found that the addition of alcohols in solution leads to an increase in the number of water molecules that bind to a complementary pair of nucleotides at the formation of intermolecular complex (in the presence of ethanol or trifluoroethanol 0.51 ± 0.09 and 1.33 ± 0.12, respectively). At the same time, alcohols interacted with single-stranded oligonucleotides and double-stranded in the same way.

115

Our Contributors

132

Instructions to Contributors

135

Вернуться на главную