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821.
822.
Stationary solitons are found to occur in two-dimensional media with a variable saturation magnetization whose square is a
harmonic function of the coordinates. It is shown in this case that the Landau-Lifshits equation can be reduced to the integrable
O(3) sigma-model in curved space. Some properties of the solutions obtained are discussed. Bibliography: 15 titles.
Translated by V. D. Lipovskii. 相似文献
823.
824.
825.
V. Ya. Popkova L. E. Vinogradova L. A. Leites V. K. Osmanov 《Russian Chemical Bulletin》1991,40(10):2075-2078
The reaction of ammonia with 2-chloroperfluoro-1-cyclohexene-1-thiocyanate leads to 2-amino-7-iminoperfluoro-4,5,6-trihydrobenzo-1,3-thiazole (II) due to intramolecular heterocyclization in the Thorpe reaction with the concurrent exoiminization. Analysis of the IR spectra of (II) in CCl4 and in the solid phase indicated that molecules of (II) in the crystal form hydrogen-bonded centrosymmetric dimers (D), which are in equilibrium with free molecules of (II) in solution.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2366–2370, October, 1991.The authors express their gratitude to D. I. Zagorevskii for taking the mass spectrum of (II) and to L. S. German for a useful discussion of this work. 相似文献
826.
827.
828.
H. Tsertos E. Berdermann F. Bosch M. Clemente S. Huchler P. Kienle W. Koenig C. Kozhuharov 《Zeitschrift für Physik A Hadrons and Nuclei》1992,342(1):79-94
We present the results obtained from systematic studies of positron creation for a series of heavy-collision systems, with united chargeZ u =Z 1 +Z 2 ranging fromZ u =164 (Pb + Pb) toZ u =184 (U+U) at bombarding energies close to the Coulomb barrier, using the Orangeβ-spectrometer at GSI. For each collision system studied, the dominating continuous distributions due to quasiatomic and nuclear positron emission are determined accurately. This is essential in obtaining the characteristics of the still unexplained monoenergetic positron lines which appear in the energy range between 200 keV and 400 keV. Our results are compared with coupled-channels calculations for quasi-atomic positron creation. The latter describe quite well the global features of the measured spectra, but overestimate systematically their absolute values. From the comparison, a common normalization factor of about 0.75 can be established for the calculated spectra. In particular, the dependence onZ u of the measured emission probabilities was found to follow a power law (∝Z u 195±1), in fair agreement with the theoretical prediction. 相似文献
829.
A. E. Zernov 《Ukrainian Mathematical Journal》1991,43(6):705-709
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 43, No. 6, pp. 755–760, June, 1991. 相似文献
830.
E. L. Belokoneva A. G. Ivanova S. Yu. Stefanovich O. V. Dimitrova V. S. Kurazhkovskaya 《Crystallography Reports》2004,49(4):603-613
Crystals of new rare earth borates of the composition Ln[B6O9 (OH)3] (Ln = Sm-Lu), sp. gr. R3c are synthesized under hydrothermal conditions. Their crystal structures are determined on single crystals with Ln = Ho, Gd without preliminary determination of their chemical formulas. The polar anionic framework of the crystals consists
of BO3 triangles and BO4 tetrahedra and has wide channels along the threefold axis of the structure, which are similar to the channels along the a, b, and c axes in cubic Li4[B7O12]Cl boracite with Li conductivity. Rare earth atoms are arranged in the structure over the cubic F pseudolattice, whereas
the analogous positions in Li boracites are filled with Cl anions. The squared optical nonlinearity of the new crystals is
comparable with the nonlinearity of quartz, whereas the electrical conductivity in borates at 300°C exceeds 10−6 S/cm.
__________
Translated from Kristallografiya, Vol. 49, No. 4, 2004, pp. 681–691.
Original Russian Text Copyright ? 2004 by Belokoneva, Ivanova, Stefanovich, Dimitrova, Kurazhkovskaya. 相似文献