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91.
92.
D. A. Vereshchagin S. B. Leble A. K. Shchekin 《Journal of Applied Mechanics and Technical Physics》1993,34(5):660-668
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 5, pp. 70–79, September–October, 1993. 相似文献
93.
We study the frequency of the plasma oscillations of electron–positron pairs created by the vacuum polarization in a uniform electric field with strength E in the range 0.2Ec<E<10Ec. Following the approach adopted in Ruffini, et al. (2007) [1] we work out one second order ordinary differential equation for a variable related to the velocity from which we can recover the classical plasma oscillation equation when E→0. Thereby, we focus our attention on its evolution in time studying how this oscillation frequency approaches the plasma frequency. The time-scale needed to approach to the plasma frequency and the power spectrum of these oscillations are computed. The characteristic frequency of the power spectrum is determined uniquely from the initial value of the electric field strength. The effects of plasma degeneracy and pair annihilation are discussed. 相似文献
94.
V. N. Kizhnyaev A. F. Pokatilov L. I. Vereshchagin L. V. Adamova A. P. Safronov A. I. Smirnov 《Russian Journal of Applied Chemistry》2006,79(7):1167-1173
Carbon-chain polymers with 1,3,4-oxadiazole rings were prepared by radical polymerization and polymer-analogous transformations. The kinetic relationships of the polymerization of vinyl-1,3,4-oxadiazole monomers and some properties of the resulting polymers were studied. The thermodynamics of interaction of poly-2-vinyl-5-methyl-1,3,4-oxadiazole, a nonionic water-soluble polymer, with water was examined. 相似文献
95.
We discuss the problem of transmitting polarized pulses along optical fibers with variable dispersion. The dissipation and mean dispersion are assumed to be zero, which allows using the model of the vector nonlinear Schrödinger equation. We consider an optical fiber consisting of arms of equal length, which is assumed to be large. We propose an asymptotic recursive procedure for calculating the amplitude and the phase of an optical pulse propagating along the optical cable with variable dispersion. 相似文献
96.
I. V. Rozhdestvenskaya T. V. Setkova O. S. Vereshchagin A. G. Shtukenberg Yu. B. Shapovalov 《Crystallography Reports》2012,57(1):57-63
The crystal structures of synthetic tourmalines with a unique composition containing 3d elements (Ni, Fe, and Co) have been refined: (Ca0.12?0.88)(Al1.69Ni 0.81 2+ Fe 0.50 2+ )(Al5.40Fe 0.60 3+ )(Si5.82Al0.18O18)(BO3)3(OH)3.25O0.75 I, a = 15.897(5), c = 7.145(2) Å, V = 1564(1) Å; Na0.91(Ni 1.20 2+ Cr 0.96 3+ Al0.63Fe 0.18 2+ Mg0.03)(Al4.26Ni 1.20 2+ Cr 0.48 3+ Ti0.06)(Si5.82Al0.18)O18(BO3)3(OH)3.73O0.27 II, a = 15.945(5), c = 7.208(2) Å, V = 1587(1) Å3 and Na0.35(Al1.80Co 1.20 2+ )(Al5.28Co 0.66 2+ Ti0.06)(Si5.64B0.36)O18(BO3)3(OH)3.81O0.19 III, a = 15.753(8), c = 7.053(3) Å, V = 1516(2) Å3. The reliability factors are R 1 = 0.038?0.057 and wR 2 = 0.041–0.060. It is found that 3d elements occupy both Y- and Z positions in all structures. The excess positive charge is compensated for due to the incorporation of divalent oxygen anions into the O3(V)+O1(W) positions. 相似文献
97.
A. A. Bredikhin V. A. Kirillovich L. V. Frolova A. N. Vereshchagin 《Russian Chemical Bulletin》1989,38(12):2476-2479
The ellipsoid of polarizability of the chloroformate fragment ClC(O)O has principle semiaxes b1=3.64, b2=5.34, b3=3.81 Å3; the angle between b1 and the C=0 bond is 24.5°. Aromatic chloroformates in solutions exist in conformations with cisoid position of the C=O and O-R bonds and the phenoxyl fragment in aromatic chloroformates deviates from the plane of the molecule.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2704–2708, December, 1989.The authors wish to thank S. G. Vul'fson for assistance in measuring the depolarization of Rayleigh light scattering. 相似文献
98.
99.
S. G. Vul'fson A. B. Teitel'baum T. G. Mannafov A. N. Vereshchagin 《Russian Chemical Bulletin》1976,25(1):86-89
1. | Molecules of arylvinyl selenides have a maximally conjugated planar s-trans structure, |
2. | The conformations of arylvinyl sulfides are determined by the ratio of the energies of conjugation and steric repulsion of atoms; the disturbance of coplanarity occurs on account of rotation of the aryl radicals. |
100.
S. N. Valitova V. E. Kataev A. N. Vereshchagin A. N. Chernov A. V. Il'yasov 《Russian Chemical Bulletin》1987,36(5):951-954
Conclusions For solutions of -methoxyethylbenzenes in nonpolar solvents it was established that the conformation with the gauche-orientated substituents in relation to the bond is preferred and the conformation with close Me and Ph groups is realized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1033–1037, May, 1987. 相似文献