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991.
992.
A carborane-containing stable simple enol — 1-2-isopropyl-o-carboran-I-yl)-1-phenyl2-mesityl-2-lrydroxyctlrylcne — has been synthesized. This enol does not isomerize to the starting ketone or keto-enol mixture even after prolonged heating in benzene in the presence of CF3COOH.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1561–1563, June, 1996. 相似文献
993.
994.
Vanadium oxide surface studies 总被引:4,自引:0,他引:4
The vanadium oxides can exist in a range of single and mixed valencies with a large variety of structures. The large diversity of physical and chemical properties that they can thus possess make them technologically important and a rich ground for basic research. Here we assess the present status of the microscopic understanding of the physico-chemical properties of vanadium oxide surfaces. The discussion is restricted to atomically well-defined systems as probed by surface techniques. Following a brief review of the properties of the bulk oxides the electronic and geometric structure of their clean single crystal surfaces and adsorption studies, probing their chemical reactivity, are considered. The review then focuses on the growth and the surface properties of vanadium oxide thin films. This is partitioned into films grown on oxide substrates and those on metal substrates. The interest in the former derives from their importance as supported metal oxide catalysts and the need to understand the two-dimensional overlayer of the so-called “monolayer” catalyst. On the single crystal metal substrates thin oxide layers with high structural order and interesting properties can be prepared. Particular attention is given to ultrathin vanadium oxide layers, so-called nano-layers, where novel phases, stabilised by the substrate, form. 相似文献
995.
G. E. Karadzhov 《Mathematische Nachrichten》1987,132(1):329-346
In this paper the results from [7, 8], concerning the asymptotic behaviour of the spectral function on the diagonal for Schrodinger operators h →0, are extended to the case of some h-admissible operators, acting in Rn, no 2. 相似文献
996.
R. L. S. Devine C. T. Foxon B. A. Joyce J. B. Clegg J. P. Gowers 《Applied Physics A: Materials Science & Processing》1987,44(2):195-200
Beryllium diffusion during MBE growth of (Al, Ga)As layers, (Al, Ga)As/GaAs heterojunctions and GaAs/AlAs superlattices has been studied by electrochemical C-V and secondary ion mass spectrometry (SIMS) concentration profiling, in conjunction with transmission electron microscopy. Diffusion times were comparatively short since they were limited to part of the growth sequence, so non-equilibrium effects had a significant influence. The results are consistent with an interstitial-substitutional mechanism in which lattice site incorporation becomes more difficult with increasing band gap enthalpy. Incorporation involves a kick-out reaction which leads to the observed disordering of the superlattices. 相似文献
997.
We study the problem of a possible rotation of the observable Universe (Metagalaxy) from the point of view of the general-relativistic theory of gravitation. We employ the concept of a hierarchical structure of reality, based on the existence of Eddington-Dirac large numbers. From the Einstein equations in their Landau-Raichaudhuri form we derive expressions for the angular momentum and angular velocity of the rotation of the Metagalaxy. These expressions give an coinciding in order of magnitude with the observed one. Using the formulas obtained, and using the hierarchy relation (large number relation), we obtain the Stanyukovich formula S N3/2 which relates the number of nucleons in the Metagalaxy N and its angular momentum S. We show that the angular velocity may decrease in inverse proportionality to the scale factor, which may explain its small value at this time. We show that the source of rotation in cosmology can be space-time torsion, induced by the spin of fermionic matter.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 12–16, March, 1987.The authors are grateful to V. F. Panov for the discussion of this paper and valuable comments. 相似文献
998.
N. K. Morozova Yu. A. Pashchenko V. D. Chernyi V. G. Galstyan T. P. Dolukhanyan V. I. Muratova 《Russian Physics Journal》1987,30(2):143-149
The nature of the luminescence of zinc sulfide in the spectral range (360), 380–420 nm (SAL) at 80K is analyzed. It is shown that the appearance of SAL radiation is accompanied by additional absorption in the region (350) 365–370 nm at 80K. The low-temperature spectra of sphalerite, exposed to different radiation and subjected to different treatment, are studied. The multiband luminescence of the isoelectronic sulfur impurity in ZnO deposits in the region 383–640 nm is discussed. It is concluded that SAL luminescence is attributable to the localization of excitons in ZnS on clusters, whose formation precedes the precipitation of the ZnO·S phase. The formation of oxygen clusters and deposits on dislocations in ZnS is studied.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 60–66, February, 1987. 相似文献
999.
One finds the asymptotic behavior of the minimax distance between the binomial and its approximating normal or Poisson distributions, taken with the second terms of their expansions.Translated from Veroyatnostnye Raspredeleniya i Matematicheskaya Statistika, pp. 4–19, 1986. 相似文献
1000.
Günter F. Steinke 《Results in Mathematics》1987,12(1-2):207-221
A new rather large family of locally compact 2-dimensional topological Laguerre planes is introduced here. This family consists exactly of those Laguerre planes which can be obtained by pasting together two halves of the classical real Laguerre plane along a circle suitably. Isomorphism classes and automorphism groups of these planes are determined. Together with [9] this gives a complete classification of all semicalssical topological flat Lguerre planes. 相似文献