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1.
The process of focusing of an inhomogeneously polarized beam passed through a system consisting of a uniaxial crystal and a polarization filter is considered. It is shown that the action of this system is equivalent to the action of a phase transparency with a complex relief of the refractive index. In particular, if the angle between the axes of the quarter-wave plate and the polarizer is equal to 45°, this transparency has a helicoidal relief. Simultaneously, two singular beams with different curvatures of their wavefronts arise in the transparency. The action of the lens consists in formation of a combined singular beam having three focal waists. The boundary wave arising upon focusing is able not only to form a new spectrum of toroidal vortices, but also to straighten the focusing region, forming a fairly extended range with a weak divergence. 相似文献
2.
VI. Sedláček 《Czechoslovak Journal of Physics》1988,38(5):465-469
The formation of slip bands is the main mechanism of cyclic deformation in pure Al. Their density, orientation and heights in polycrystalline Al were investigated during cycling. Types, sizes and densities of precipitates are responsible for the mode of cyclic deformation in AlCu4 pure alloy. In technical Al alloys intermetallic phases have detrimental effects on deformation homogeneity and largely govern the fatigue mechanism of the material and especially microcrack initiation. 相似文献
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Sokolova N. P. Varand V. L. Romanenko G. V. Lisoivan V. I. Fadeeva V. P. Sheludyakova L. A. 《Russian Journal of Coordination Chemistry》2003,29(5):362-368
Two isomers with empirical formula C6H6F9O9Tb are synthesized and their structures are studied. Isomerism was found to arise due to different positions of a proton. Crystals of two isomers are isostructural and form continuous series of solid solutions with C6H6F9O9Eu. 相似文献
5.
Tikhova V. D. Shakirov M. M. Fadeeva V. P. Dergacheva M. I. Samutenko L. V. Fedorova L. V. 《Russian Journal of Applied Chemistry》2002,75(5):829-833
Quantitative and qualitative changes in humic acids of meadow soddy soils, occurring under the action of various fertilizer systems, were studied by 13C and 31P NMR. 相似文献
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T. N. Deshko A. V. Kamernitskii G. A. Kogan A. M. Turuta T. K. Ustynyuk T. M. Fadeeva 《Russian Chemical Bulletin》1976,25(12):2524-2528
1. | Study has been made of the circular dichroism spectra of 20-ketosteroids containing a three-membered ring (methylene, epoxide, episulfide, or aziridine) in the -position with respect to the keto group. |
2. | The observed n* and * transition Cotton effects have been correlated with the preferred conformation of the molecule. |
10.
Conclusions Replacement of the 20-oxo group in 17,21-epoxypregn-5-en-3-ol-20-one by the hydrazono-group affects the cleavage of the oxetane ring by thiocyanic acid, reaction occurring preferentially by introduction of–NCS at C17 with consequent expansion of the four-membered ring to a six-membered ring with the formation of the [17; 21]-1,3-tetrahydrooxazine-2-thione.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1393–1396, June, 1987. 相似文献