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排序方式: 共有348条查询结果,搜索用时 15 毫秒
1.
L. I. Bryukvina E. A. Ermolaeva S. N. Pidgurskiĭ L. F. Suvorova V. M. Khulugurov 《Physics of the Solid State》2006,48(1):68-72
It was detected for the first time that films consisting of a transition-metal-based structure form (via thermal diffusion
of intracrystalline impurities) on the surface of alkali-halide (LiF, NaF) crystals activated by transition metals Co, Ni,
or Mn. The thickness, density, and composition of the films are shown to be different, depending on the heat treatment conditions.
The crystals were annealed at temperatures varying from 473 to 1073 K in vacuum and air. The surface structures forming upon
annealing in vacuum exhibit magnetic properties. The films were studied by optical, x-ray fluorescence, and electron spectroscopy
to reveal the mechanisms of transition-metal film formation during thermal annealing. 相似文献
2.
水下光通信充分利用了海水对激光的衰减窗口效应,具有隐蔽、安全、非接触和快速机动等特性,兼具无线通信和光纤通信的优点,其关键技术在于光收发端机的研制;PPM(Pulse Position Modulation)数字脉冲位置调制具有低平均功率和高峰值功率等特性,特别适合用于无线数字光通信。两者性能的融合需要高灵敏度数字光接收机的实现。利用阵列光电检测接收、高速A/D转换和信号处理等相关技术,采用DSP处理器,高灵敏度的数字光PPM接收机得以实现,实验和测试表明它大大降低了接收机对于整个系统信噪比的要求,获得了较好的性能。 相似文献
3.
AO Sheng-Mei YAN Jia-Ren 《理论物理通讯》2007,47(1):15-18
Three types of expression in the dark-soliton perturbation theory based on squared Jost solutions are invesgigaged in ghis paper. It is shown that there are three formally different results about the effects of perturbagion on a dark soliton, and it is proved by means of a transformation between two integral variables that they are essentially equivalent. 相似文献
4.
A. N. Titov O. N. Suvorova S. Yu. Ketkov S. G. Titova A. I. Merentsov 《Physics of the Solid State》2006,48(8):1466-1471
Single crystals and polycrystals of titanium diselenide TiSe2 intercalated with ferrocene Fe(η5-C5H5)2 and cobaltocene Co(η5-C5H5)2 are synthesized. The magnetic susceptibility and electrical resistivity of the intercalation compounds are measured. The results obtained demonstrate that the intercalation brings about the formation of an impurity band with a temperature-dependent width. 相似文献
5.
Suvorova V. V. Panicheva L. P. Mamontova Yu. V. Belyatskii M. K. 《Russian Journal of Organic Chemistry》2003,39(7):957-962
Selective dehydrobromination of 1,2-dibromo-1-phenylethane to -bromostyrene was effected under conditions of phase-transfer catalysis in systems containing KOH, toluene, and tetraalkylammonium bromides. The high selectivity of the catalytic systems originates from stabilization by lipophilic cation of the phase-transfer catalyst of a E1cb-like transition state in the E2 mechanism. In the presence of a catalytic amount of lipophilic alcohols, phenylacetylene was obtained. Substrate activation by alcohol molecules is explained by enhancement of the acceptor power of halogen atoms due to solvation and by increased mobility of hydrogen atoms. 相似文献
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B. A. Tertov Yu. G. Bogachev Yu. V. Koshchienko G. M. Suvorova E. B. Tsupak N. K. Chub S. F. Breus 《Chemistry of Heterocyclic Compounds》1986,22(8):868-872
Organolithium and organosodium compounds of 1,2-dimethyl-, 1-methyl-2-ethyl-, 1-methyl-2-propyl-, and 1-phenyl-2-methylbenzimidazole, containing the metal in the alkyl group at position C(2), were obtained by metallation. It was found that metallation can be complicated by the addition of the metalling reagent at the C=N bond of the heterocycle. It was shown that the obtained organometallic compounds can be used for the synthesis of various derivatives of benzimidazole.The calculation was performed with the standard bond lengths. A planar model was used for the carbanion.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1073–1077, August, 1986. 相似文献
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