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71.
For a thin ferromagnetic film, the braking process of a 180° domain boundary in a field of randomly distributed point defects
is studied using perturbation theory. It is established that, for low velocities, the motion of the boundary is nonsteady-state.
It is shown that the critical velocity of steady-state motion depends substantially on film thickness and the defect concentration.
Fiz. Tverd. Tela (St. Petersburg) 41, 1231–1235 (July 1999) 相似文献
72.
V. V. Bel’kov Yu. V. Zhilyaev G. N. Mosina S. D. Raevskii L. M. Sorokin M. P. Shcheglov 《Physics of the Solid State》2000,42(9):1606-1609
The structure of bulk GaN layers grown on (0001) sapphire substrates by vapor-phase epitaxy has been studied by x-ray diffraction and transmission electron microscopy (TEM). It is found that these layers contain grown-in and screw dislocations. The dislocation density decreases away from the interface. The effect of an amorphous buffer layer on the formation of the initial GaN layer and, thus, on the degree of perfection of gallium nitride layers is elucidated. A model of generating grown-in dislocations and the relaxation mechanism of misfit stresses are proposed. 相似文献
73.
The equilibrium shape of the interface between superfluid and crystalline 4He near the (0001) orientation is analyzed. A feature is observed in the edge angle as a function of the wall inclination with respect to the gravitational field. The step energy on the basal plane of the crystal is measured. 相似文献
74.
A. R. Sorokin 《Journal of Russian Laser Research》1986,7(4):332-345
Working-level-population processes are analyzed on the basis of detailed investigations of the amplitude-time structure of the laser and spontaneous emission following a pulsed electric discharge in the mixtures He + R (R = Ar, Kr, Xe), Ar + Xe. Account is taken in the analysis of excitation by electrons (direct and stepwise) and of population as a result of relaxation processes (collisions of second kind with electrons; radiative cascades, recombination processes; collisions with the atoms of the working and buffer gases; excitation transfer from helium molecules). It is concluded that under optimum efficiency conditions inversion is produced in the lasers considered as a result of direct electron collision with the working atoms (Ar, Kr, Xe), which are in the ground state.Translated from Lazernye Sistemy, pp. 15–34, 1982. 相似文献
75.
V. É. Kisel’ V. G. Shcherbitsky N. V. Kuleshov V. I. Konstantinov V. I. Levchenko E. Sorokin I. Sorokina 《Optics and Spectroscopy》2005,99(4):663-667
The temperature and concentration quenching of the luminescence of Cr2+ ions in Cr:ZnSe crystals is experimentally investigated and the radiative lifetime of the upper lasing level is determined. The values of the cross sections of absorption from the ground state of Cr2+ ions in Cr:ZnSe crystals are refined. It is shown that the absorption from the excited state of Cr2+ ions is negligible near 1.5 μm. Lasing in Cr:ZnSe single crystals is implemented with an efficiency of 31% and an output power of 186 mW using laser diode pumping at a wavelength of 1.77 μm. 相似文献
76.
We consider the oblique incidence of a small-amplitude plane electromagnetic wave on a layer of turbulent absorbing plasma in a uniform external magnetic field. The equations for the first two statistical moments of the angular power spectrum of scattered radiation are derived in the geometrical-optics approximation. We show that two asymmetry factors of the problem, i.e., the oblique incidence and the influence of the anisotropic medium, compensate for each other along a certain direction and impede the appearance of the effect of displacement of the power-spectrum maximum and the effect of anomalous spectrum broadening. We find the condition at which such a case of wave propagation is realized. The dependence of the angular-spectrum shape on the distance from the plasma-layer boundary is studied numerically without using the small-angle approximation. The calculations confirm the results obtained using the geometrical-optics approximation. 相似文献
77.
78.
G. A. Ksendzova G. I. Polozov I. V. Skornyakov V. L. Sorokin G. B. Tolstorozhev O. I. Shadyro A. A. Yakunin 《Optics and Spectroscopy》2007,102(4):551-556
The intermolecular interactions in solutions of aminophenols in CCl4 are studied by the methods of IR Fourier spectroscopy. If the hydroxyl groups of aminophenol molecules occupy the ortho positions with respect to the amino groups of the molecules, the hydroxyl and amino groups are involved in intramolecular interactions with the formation of hydrogen bonds O-H...N and N-H...O. The introduction of two additional tert-butyl groups into the structure of the aminophenol molecule facilitates the formation of O-H...N bonds and impedes the formation of N-H...O bonds. The occurrence of the carbonyl group in the structure of aminophenols leads to the formation of intramolecular hydrogen bonds O-H...O=C. The introduction of the methyl groups into carbonyl-containing aminophenols transforms the O-H...O=C bond into the hydrogen bond N-H...O=C. 相似文献
79.
80.
V. N. Sorokin 《Proceedings of the Steklov Institute of Mathematics》2017,298(1):294-316
Multiple orthogonal polynomials for three discrete Meixner measures with identical exponential decay at infinity are studied. These polynomials are the denominators of the type II Hermite–Padé approximants to some hypergeometric functions. The limit distribution of zeros of such polynomials scaled in a certain way is described in terms of equilibrium logarithmic potentials and in terms of algebraic curves. 相似文献