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排序方式: 共有59条查询结果,搜索用时 31 毫秒
31.
V. P. Koshcheev D. A. Morgun T. A. Panina Yu. N. Shtanov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2012,6(6):997-999
The influence of multiple scattering and quantum fluctuations in the transverse coordinate, momentum, and energy on the channeling of relativistic protons in a silicon crystal have been studied by computer simulation. 相似文献
32.
L. I. Kuznetsova N. I. Kuznetsova S. V. Koshcheev V. A. Rogov V. I. Zaikovskii B. N. Novgorodov L. G. Detusheva V. A. Likholobov D. I. Kochubey 《Kinetics and Catalysis》2006,47(5):704-714
The transformations of platinum and a heteropoly acid (HPA) in binary systems prepared from H2PtCl6 or H2PtCl4 and H3PMo12O40 were studied using IR and UV-VIS spectroscopy, elemental analysis, XPS, EXAFS, TPR, and HREM. The calcination of platinum chloride with the HPA to 450°C resulted in the formation of a platinum salt of the HPA along with decomposition products (mixture I). The reduction of calcined samples containing Pt: HPA = 1: 1 with hydrogen at 300°C (mixture II) followed by exposure to air resulted in the regeneration of the HPA structure. The resulting solid samples of Pt 1?n 0 Pt n II ClmOxHy) (H3+p PMo 12?p VI Mo p V O40) (III) contained platinum and molybdenum in both oxidized and reduced states. The following association species were isolated from mixtures I and II by dissolving in water: [Pt n II PMo12O40] (I s) (n = 0.3?0.8) and [Pt n 0 PMo 12 red O40] (II s) (n ≈ 1). Under exposure to air, the solutions of I s were stable (pH ~2), whereas Ptmet was released from II s. After the drying of I s, the solid association species (Pt n II ClmOxHy). (H3PMo12O40), where n = 0.3?0.8, m = 0.2?1, and x = 3?0, (I solid) were obtained. The I solid/SiO2 supported samples were prepared by impregnating SiO2 with a solution of I s and drying at 100°C. Platinum metal particles of size ~20 Å and a mixed-valence association species of platinum with the HPA were observed after the reduction of I solid/SiO2 with hydrogen at 100–250°C. These samples were active in the gas-phase oxidation of benzene to phenol at 180°C with the use of an O2-H2-N2 mixture. 相似文献
33.
V. A. Koshcheev 《Proceedings of the Steklov Institute of Mathematics》2009,264(1):155-167
Efficient versions of the Cauchy criterion for the convergence in L p of greedy approximants of trigonometric Fourier series are discussed. 相似文献
34.
35.
V. A. Koshcheev 《Mathematical Notes》1975,17(2):114-119
The connectivity of suns is investigated. It is shown that a sun is connected in finite-dimensional space. A set M in uniformly convex space X is shown to be approximatively compact if and only if M is P-compact and the metric projection of X onto M is upper semicontinuous. 相似文献
36.
A. I. Stadnichenko S. V. Koshcheev A. I. Boronin 《Moscow University Chemistry Bulletin》2007,62(6):343-349
Gold oxide films obtained on the surface of polycrystalline gold foil upon oxidation by oxygen activated by a high-frequency discharge have been studied by X-ray photoelectron spectroscopy. High-frequency O2 activation affords oxide films more than 3–5 nm thick. As follows from Au4f spectra, the surface gold atoms are oxidized to the oxidation state +3. The O1s spectra have a composite shape and are decomposed into four components that characterize nonequivalent states of oxygen in the resulting oxide films. It is assumed that the two major oxygen states (E b(O1s) = 529.0 and 530.0 eV) correspond to the oxygen atoms in two-and three-dimensional gold oxide Au2O3, respectively. The oxygen states characterized by the higher binding energies (E b(O1s) = 531.8 and 535.2 eV) likely correspond to molecular oxygen in peroxide and superoxide groups, respectively. 相似文献
37.
T. A. Panina V. P. Koshcheev D. A. Morgun N. V. Safin 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(2):161-164
Expressions for the potential energy of interaction between a fast neutral atom or a multiply charged ion and a crystal atom
are obtained, both with and without regard for the Pauli principle. Results from computer simulation of the heating of silver
ions with a fixed value of the charge state in passing through the (110) planar channel of a silicon crystal are presented.
It is shown that the rate of dechanneling can be estimated by the form of the potential energy of interaction of an incident
ion with a continuous potential of the planar crystal channel. 相似文献
38.
V. P. Koshcheev D. A. Morgun T. A. Panina Yu. N. Shtanov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2012,6(1):168-171
A system of equations describing multiple scattering by crystal nuclei and electrons, and also quantum fluctuations of the
coordinate and momentum operators of fast charged particles has been obtained. Quantum corrections to the classical equations
of motion have been determined in quasiclassical approximations. A computer simulation of 855-MeV electron and positron motion
in the (110) planar channel of a Si crystal has been carried out. The inclusion of quantum fluctuations in the equation of
motion affects the dynamics of the electron channeling effect in planar crystal channels considerably; in particular, intense
dechanneling (heating) occurs. Intense rechanneling (cooling) occurs in the case of positrons. 相似文献
39.
40.
B. V. Koshcheev A. M. Maksimov V. E. Platonov V. V. Shelkovnikov 《Russian Journal of Organic Chemistry》2017,53(7):1012-1016
Reactions of 1-(difluoromethanesulfinyl)pentafluorobenzene with sodium methoxide, sodium phenoxide, potassium hydrosulfide, and methylamine resulted in substitution of fluorine atom in the 4-position (in the reaction with methylamine, also in the 2-position). Treatment of the title compound with sodium hydroxide afforded pentafluorobenzene due to cleavage of the Carom?S bond. 相似文献