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排序方式: 共有191条查询结果,搜索用时 31 毫秒
1.
A two-dimensional self consistent model of the Beam-Plasma-Discharge (BPD) has been developed to calculate the discharge ignition of a bandlike electron beam in a discharge chamber. The discharge was considered in Argon with an initial concentration of 1014 cm?3. The model allows calculation of the time evolution of perpendicular profiles of electron density, temperature and the potential. 相似文献
2.
S. V. Popkov L. V. Kovalenko V. P. Tashchi L. Ya. Bogel'fer 《Russian Chemical Bulletin》1994,43(8):1363-1367
The reaction of dimethylsulfonium methylide with the carbonyl function of 2-arylidene-cyclohexanones obtained from 2-methylcyclohexanone affords the corresponding spirooxiranes. The application of this reaction to 2,2-dimethyl-6-(5-methylfurfurylidene)cyclohexanone and 2,2-dimethyl-6-(5-chlorofurfurylidene)cyclohexanone leads to substituted 4,4-dimethyl-1-furyl-1,-3,4,5,6,7-hexahydroisobenzofurans.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1439–1443, August, 1994. 相似文献
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Ring opening in 2-alkyl-4,5-dihydrooxazoles by the action of azoles gave intermediate N-(2-azolylethyl)alkanamides, whose hydrolysis afforded N-(2-aminoethyl)azoles.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1781–1784, October, 2006. 相似文献
5.
Glycine-nitrate combustion method was used to obtain nanopowders of orthorhombic and hexagonal yttrium orthoferrite with particles sizes in the ranges from 30 to 53 nm and from 6 to 14 nm, respectively. It is shown that the structure and size of the particles are determined by the process temperature, which depends on the relative amounts of glycine and nitrates in the initial mixture. It is shown that yttrium orthoferrite nanopowders with a certain crystal structure and particle size can be obtained by varying the glycine/nitrate ratio. The nanopowders and materials on their basis can be used as photocatalysts. 相似文献
6.
K. A. Shashkeev O. V. Popkov G. Yu. Yurkov S. V. Kondrashov A. A. Ashmarin M. I. Biryukova 《Russian Journal of Applied Chemistry》2016,89(4):644-649
Tribological materials based on molybdenum disulfide nanoparticles localized on the surface of ultradispersed polytetrafluoroethylene were prepared. The composition and properties of the new composite materials were studied. Introduction of ultradispersed additives based on polytetrafluoroethylene with MoS2 and on polytetrafluoroethylene and nanodiamonds prepared by detonation synthesis (taken as reference samples) decreases the viscosity of MS-20 aviation oil. The dependence of the friction coefficient on the Sommerfeld number for the composites obtained was examined. Introduction of additives leads to a decrease in the friction coefficient with increasing linear sliding velocity, in contrast to the initial oil for which the trend is opposite. The dependence of the friction coefficient on the concentration of additives in the initial oil was demonstrated. Modification of polytetrafluoroethylene microgranules with 3 wt % MoS2 nanoparticles allows the amount of additive to the oil to be considerably reduced. 相似文献
7.
Lvova N. A. Ryazanova A. I. Popkov D. O. 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2020,94(2):415-422
Russian Journal of Physical Chemistry A - The results are presented from quantum-chemical modeling of the chemisorption of atomic hydrogen and fluorine on the surface of a hexagonal boron nitride... 相似文献
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Milan Nádvorník Vratislav Langer Robert Jirásko Michal Holčapek Tomáš Weidlich Antonín Lyčka Alexander Popkov 《Polyhedron》2008
A preparative procedure for the synthesis of an important chiral synthon of side-chain protected tyrosine was developed and optimised for the minimisation of nickel salts waste. While preparing a similar side-chain protected tryptophan synthon, an unexpected low stability was found of the Boc-protective group of the tryptophan aromatic nitrogen during purification on silica gel. X-ray crystal structure determination, tandem mass spectrometry (MS/MS) and NMR were applied for the elucidation of the structures of the prepared complexes and by-products. Stereochemistry of products of α-methylation of the complexes was assessed using a model tyrosine-derived compound. 相似文献