"Technical Physics Letters"

Afanas’ev, V. V.;Danilaev, M. P.;Pol’skii, Yu. E.

doi: 10.1134/S1063785010040012pmid: N/A

Abstract Parameters of external inertial actions capable of stabilizing a fractal oscillator so as to ensure a required regime (mode) of its dynamic behavior are determined. It is shown that the restoring force in the nonlinear fractal oscillator under consideration depends on the square amplitude of the external harmonic action and on an alternating-sign factor.

Surkaev, A. L.;Mukha, Yu. P.;Kumysh, M. M.

doi: 10.1134/S1063785010040024pmid: N/A

Abstract The pressure developed by an acoustic shock wave and the integral of action of the electric discharge formed during the electric explosion of a flat foil ring in a condensed medium are evaluated by assuming a quasi-stationary character of the process.

Tren’kin, A. A.

doi: 10.1134/S1063785010040036pmid: N/A

Abstract The fractal dimension of a lightning discharge is determined. It is established that, with respect to the fractal dimension and, hence, the character of spatial structure organization, the lighting discharge is analogous to high-voltage discharges of other types, including streamer corona, surface, nanosecond diffuse, spark, and streamer-free discharges. This analogy leads to a conclusion concerning the generality of physical mechanisms involved in the self-organization of various high-voltage discharges.

Kishov, M. -R. G.;Magomedgadzhiev, Kh. I.;Kishov, K. M. -R.;Omarova, P. Kh.

doi: 10.1134/S1063785010040048pmid: N/A

Abstract A cell with rotating electrodes for studying discharge in gas flow is described. It is demonstrated that, using a reasonable combination of the values of external longitudinal magnetic field, flow velocity, and electrode rotation rate, it is possible under certain conditions to control the delay of gas breakdown and the duration of a short volume discharge preceding the discharge contraction stage.

Sidorenko, A. A.;Budovskii, A. D.;Postnikov, B. V.;Zverkov, I. D.;Zanin, B. Yu.;Kozlov, V. V.;Maslov, A. A.

doi: 10.1134/S106378501004005Xpmid: N/A

Abstract The possibility of controlling flow separation on an oblique airfoil using dielectric-barrier discharge has been experimentally studied. The experiments were performed at subsonic flow velocities in a broad range of the angle of attack. The results of measurements of the velocity and surface pressure fields and an analysis of the flow patterns show that the application of electric discharge allows the interval of the angles of attack for separation-free flow past the airfoil to be significantly increased. Various discharge regimes have been studied, including those with continuous activation by single voltage pulses with a frequency of 0.5–5 kHz and by pulse trains at a repetition rate of 1–100 Hz. The efficiency of the flow separation control has been studied as dependent on the electrical parameters, frequency characteristics, and position of the discharge relative to the flow separation line.

Poletika, T. M.;Girsova, S. L.;Pshenichnikov, A. P.

doi: 10.1134/S1063785010040061pmid: N/A

Abstract Interrelation between the oscillatory instability of strain localization in the hardening-softening regime at the parabolic stage of plastic flow (strain hardening), on one hand, and a cyclic character of the dislocational transformations at the strain localization focus during its transformation into a neck, on the other hand, is established in hexagonal close-packed zirconium alloys.

Fateev, E. G.

doi: 10.1134/S1063785010040073pmid: N/A

Abstract A superlow elastic stability of low-saline NaCl-H2O ice in a broad range of low temperatures (100–215 K) has been observed under the conditions of strong uniaxial compression. The level of elastic stability of the saline ice (containing a low mass fraction of NaCl within p = 0.0001–0.01) was 15–30 times smaller than in pure freshwater ice. This phenomenon can be used for the controlled production of steam, hydrogen, and oxygen using explosive fragmentation and in other low-temperature processes involving ice.

Bazhenov, A. N.;Bulovich, S. V.;Gall, L. N.;Kretinina, A. V.;Lapushkin, M. N.;Gall, N. R.

doi: 10.1134/S1063785010040085pmid: N/A

Abstract The fragmentation of molecular ions formed upon the electrospraying of a sample and transported through the gasdynamic system of a mass spectrometer equipped with an IESAP (Ion Extraction from Solution at Atmospheric Pressure) source has been experimentally studied. It is established that ion fragmentation in a Kantorowicz-Gray type cell takes place in the immediate vicinity of a skimmer port, apparently, as a result of collisions between ions (accelerated in an electric field) and stagnant gas. Molecular mechanisms of fragmentation are considered and it is concluded that this process can take place in a single ion-molecule collision event.

Shurpo, N. A.;Vakshtein, M. S.;Kamanina, N. V.

doi: 10.1134/S1063785010040097pmid: N/A

Abstract Issues pertaining to the effect of quantum dots (QDs) on the properties of a nematic liquid-crystalline mesophase are briefly considered. The influence of nanoobjects representing CdSe/ZnS semiconductor QDs on the temporal characteristics of liquid crystals (LCs) belonging to the class of cyanobiphenyls has been studied for the first time. It is established that the presence of QDs leads to a significant decrease in the time of LC molecule reorientation from planar to homeotropic position in the nanoobject-sensitized medium.

Dedkov, G. V.;Kyasov, A. A.

doi: 10.1134/S1063785010040103pmid: N/A

Abstract Expressions for the rate of radiative heat exchange between two spherical particles with temperatures T 1 and T 2 spaced by distance R in an equilibrium photon gas with temperature T 3 is obtained for the first time in a dipole approximation within the framework of fluctuation electrodynamics.