Effect of electrostatic field and high-frequency vibrations on the dislocation motion of alkalihalide crystals. Dislocation oscillation
Effect of electrostatic field and high-frequency vibrations on the dislocation motion of alkalihalide crystals. Dislocation oscillation
N.A. Tyapunina, A.A. Svetashov, E.P. Belozerova
The effect of an electrostatic field on internal friction and the defect in Young's modulus in the kilohertz range of frequencies is studied by means of two- and three-component resonance oscillators. It is estab- lished that in the range of amplitudes 10$^{-6}$ - 10$^{-4}$, the electrostatic field affects internal friction and the defect of Young's modulus. The height of the internal friction maxima observed in this range of deformation amplitudes increases under the influence of the electrostatic field, the maxima shift into the region of lower deformation amplitudes, and other maxima appear which are not present in the absence of the electrostatic field. The effect of the electrostatic field on the defect in Young's modulus manifests Itself in an increase in the absolute size of the defect as well as in a variation in the course of the dependence of the defect of Young's modulus on time and deformation amplitude. From an analysis of the internal friction and defect results, it is concluded that an electrostatic field leads to a growth in the amplitude of the oscillations of the dislocation segments and an increase in the number of active dislocations contributing to internal friction.
Show AbstractTwo canals of recombination on real silicon surfaces
Two canals of recombination on real silicon surfaces
V.V. Murina , Yu.F. Novototskii-Vlasov , Т.V. Fadeevа
Two recombination channels are found on a real Si surface, yielding comparable contributions to the rate of surface recombination. These channels are associated with two types of recombination centers, the first of which corresponds with the discrete level located near the middle of the forbidden Si zone, and the second of which with levels continuously distributed throughout the forbidden zone. The first type of recombination center appears upon localization of water molecules near definite defects at the Si-oxide interface, and the second type of center, upon the removal of the SiOF$_{2}$ group oxide in the process of different thermal and chemical treatments. It is shown that the first type of recombination center is twice as effective in recombination than the first type.
Show AbstractThe exchange interaction and magnetic anisotropy in yttrium-iron garnets with small quantity of Sm$^{3+}$-ions
The exchange interaction and magnetic anisotropy in yttrium-iron garnets with small quantity of Sm$^{3+}$-ions
N.V. Vо1kоva , L.P. Кaburina, L.P. Mitina
The magnetic anisotropy of five monocrystals in the yttrium iron-garnet system Y$3_x$Sm$_x$Fe$_5$E$_12$, where x = 0.0, 0.01%, 0.1%, 0.2%, and 0.5% is studied by means of ferromagnetic resonance. At temperatures from 10 to 90°C, the experimental values of К vary with temperature as 1/T$^{3}$. It is proposed that in this temperature region, the crystalline field acting on the Sm$^{3+}$ ions is basically cubic in structure. For a compound with x = 0.2%, the strength of the exchange field of approximately 47.6°K is found at a temperature of approximately 15°K acting from the Fe$^{3+}$ ions to the Sm$^{3+}$ ions. In a single-ion approximation at 0°K, the first and second theoretical anisotropy constants are computed, and are found to be in satisfactory agreement with experimentally found values of K1 and K2. It is concluded that anisotropy of dilute samarium garnets is basically single-ion in nature.
Show AbstractAbout measurement method of velocity field in separation of flow
About measurement method of velocity field in separation of flow
B.S.Agrovsky, E.P. Anisimova, A.G. Zatsepin, M.M. Maseev, A.A. Speranskaya
A method is described for measuring the velocity field in separated flow based on the use of a movable-electrode electron tube [mechanotron] as the velocity transducer. The profiles of the horizontal components of the mean velocity measured by means of a DIZA hot-wire anemometer adopted as standard device and by means of an anemometer with sensing element in the form of a mechanotron are compared under the conditions of nonseparated flow. It is shown that the hot-wire anemometer technique is inappropriate for measuring velocity fields in separated flow.
Show AbstractThe investigation of dependence of remanent magnetization of naturely Fe(3)O(4) on the frequency magnetic field
The investigation of dependence of remanent magnetization of naturely Fe(3)O(4) on the frequency magnetic field
V.I. Maksimochkin, V.I. Trukhin
In the present paper, the relation between irreversible magnetic properties of natural magnetite polycrystals and the frequency of a magnetic field in the range of frequencies 50-10$^{5}$ Hz is studied. An amplification of the degree of magnetization with an increase in the frequency of the magnetizing field, beginning with frequencies on the order of several hundred hertz, is observed for all the types of remanent magnetization studied (normal, Ideal, and natural). The resulting effect is attributed to the influence of a magnetic-diffusion type barrier on the magnetic structure of the samples.
Show AbstractSpectrometer of electrons and protons for measurements in the earth's magnetosphere by satellites
Spectrometer of electrons and protons for measurements in the earth's magnetosphere by satellites
Ju.V. Mineev, E.S. Spirkоva
A description of a technique and the physical characteristics of a spectrometer for recording electrons with energies Ee in the range 0.04-3.0 MeV and protons with Ep in the range 0.5-3.0 MeV over several energy intervals in the earth's magnetosphere using satellite-borne apparatus is presented. Electrons and protons are recorded by means of an improved telescope specially adapted for magnetosphere measurements consisting of four semiconductor detectors as well as gas-discharge counters.
Show AbstractCentimetre wind waves on currents
Centimetre wind waves on currents
G.E. Kononkova, К.V. Pokazeev, L.L. Tarasov
The present article is devoted to an experimental study of centimetric wind waves generated in currents. A dependence between the characteristics of the distribution functions of the wave amplitudes and the wind and current speed is shown. A hydrodynamic contrast coefficient which describes the variation of the mean wave heights and wavelengths with the variable current speed is introduced, and it is shown that this coefficient is independent of wind speed. New dimensionless magnitudes of the phase velocity of the waves and their frequency are proposed.
Show AbstractInvestigation of vacances and impurity dypoles influence on the mechanical properties NaCl crystals
Investigation of vacances and impurity dypoles influence on the mechanical properties NaCl crystals
I. Sarkozi, A.A. Predvoditelev
The influence of bivalent impurities on microhardness and yield strength is studied using highly purified samples of NaCl. An attempt is made to divide the hardness contributions due to electrical interactions of dislocations and individual vacancies and elastic interaction with dipole impurities.
Show AbstractOn the form of the shock wave in a medium with third-order nonlinearity
On the form of the shock wave in a medium with third-order nonlinearity
V.F. Marchenko, A.M. Streltsov
It is experimentally established that a sinusoidal wave in a medium with third-order nonlinearity is transformed into a wave with secondorder nonlinearity. Results are presented from a computation of the variation in the wave spectrum before and after the formation of a discontinuity.
Show AbstractPhase transition in the nonlinear fermion model
Phase transition in the nonlinear fermion model
A.A. Gvozdev, G.A. Sardanashvili
The use of the Wilson-Fisher renorm-group method shows that there exists a phase transition in the nonlinear fermion model.
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