排序方式: 共有47条查询结果,搜索用时 15 毫秒
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I. P. Raevskii L. A. Reznichenko M. P. Ivliev V. G. Smotrakov V. V. Eremkin M. A. Malitskaya L. A. Shilkina S. I. Shevtsova A. V. Borodin 《Crystallography Reports》2003,48(3):486-490
(Na, K)NbO3 crystals with a perovskite structure and a KNbO3 content up to 40 mol % were grown from flux with the use of the solvent NaBO2. The dielectric measurements of the crystals grown revealed phase transitions that had never been observed before in ceramic samples. 相似文献
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V. P. Sheverdov O. V. Ershov A. V. Eremkin O. E. Nasakin I. N. Bardasov V. A. Tafeenko 《Russian Journal of Organic Chemistry》2005,41(12):1757-1763
β,β,γ,γ-Tetracyanoalkanones react with acrolein at a high rate to afford the corresponding 2-substituted 4-formyl-3-cyclopentene-1,1,2-tricarbonitriles in high yields. The reaction occurs under mild conditions and is quite applicable for modification of natural and biologically active compounds possessing an R′CHC(O)CR3 fragment to obtain their derivatives containing three cyano groups. 相似文献
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The reaction of tetracyanoethylene with α,β-unsaturated aldehydes under hydrochloric acid catalysis leads to 2,4-dialkyl-7-imino-6-oxabicyclo[3.2.1]oct-3-ene-1,8,8-tricarbonitriles. The structures of these new cyclohexene derivatives were determined by NMR experiments and X-ray crystallography. 相似文献
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I. P. Raevskii V. V. Eremkin V. G. Smotrakov M. A. Malitskaya S. A. Bogatina L. A. Shilkina 《Crystallography Reports》2002,47(6):1007-1011
Single crystals of the composition PbFe1/2Ta1/2O3 are grown by the method of mass crystallization from flux. It is established that, unlike the PbFe1/2Ta1/2O3 ceramic, the synthesized single crystals possess pronounced relaxor properties: the maximum of the dielectric constant is diffuse and its temperature, T m, increases by more than 70 K with an increase in the frequency from 102 to 106 Hz. It is assumed that the unusual properties of the PbFe1/2Ta1/2O3 crystals are caused by mesoscopically inhomogeneous compositional ordering and comparatively high conductivity providing favorable conditions for the appearance of the volume-charge and thermal electron polarization. 相似文献
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O. V. Ershov A. V. Eremkin Ya. S. Kayukov A. N. Lyshchikov O. E. Nasakin V. A. Tafeenko 《Russian Journal of Organic Chemistry》2008,44(4):570-576
2-(4-Amino-2,5-dihydro-1H-imidazol-4-ylidene)malononitriles were synthesized by three-component reaction of tetracyanoethylene, carbonyl compound, and ammonium acetate. The synthesis can be performed in two steps with intermediate isolation of 2-aminoethene-1,1,2-tricarbonitrile, as well as using preliminarily prepard 2-aminoethene-1,1,2-tricarbonitrile and 1,3,5-trisubstituted 2,4-diazapentadienes. 相似文献
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A. V. Pavlenko V. G. Smotrakov S. P. Kubrin L. A. Shilkina V. V. Eremkin S. I. Shevtsova L. A. Reznichenko 《Bulletin of the Russian Academy of Sciences: Physics》2017,81(3):334-336
The structure, Mössbauer effect, and dielectric characteristics of 0.95PFN-0.05BFO crystals prepared via mass crystallization are studied. It is shown that temperatures approaching those of the antiferromagnet → paramagnet and ferroelectric → paraelectric transitions are reached inside these crystals, in contrast to PFN. 相似文献
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A. T. Kozakov A. V. Nikol’ski? V. P. Sakhnenko A. N. Pavlov V. G. Smotrakov V. V. Eremkin 《Physics of the Solid State》2009,51(7):1385-1389
Spectra of anomalous electron emission from the surface of solid solutions in the (1 − x)PbMg1/3Nb2/3O3 + xPbTiO3 system with x = 0.06, 0.10, 0.13, 0.20, and 0.25 have been studied. While the energy characteristics of the anomalous electron emission
spectra vary monotonically with x, the behavior of integrated intensity was found to be nonmonotonic with a maximum occurring at x = 0.1. According to the proposed interpretation, the results obtained are explained by the effect of the potential barrier
on the electron emission; the potential barrier depends, in turn, on the permittivity ε of the samples.
Original Russian Text ? A.T. Kozakov, A.V. Nikol’skiĭ, V.P. Sakhnenko, A.N. Pavlov, V.G. Smotrakov, V.V. Eremkin, 2009, published
in Fizika Tverdogo Tela, 2009, Vol. 51, No. 7, pp. 1310–1314. 相似文献
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V.?N.?MaksimovaEmail author O.?V.?Ershov K.?V.?Lipin A.?V.?Eremkin O.?E.?Nasakin 《Russian Journal of Organic Chemistry》2012,48(3):426-429
The reaction of 5,6-dialkyl-2-halopyridine-3,4-dicarbonitriles with alcoholic ammonia under elevated pressure gave 5,6-dialkyl-2-aminopyridine-3,4-dicarbonitriles
as a result of nucleophilic replacement of the halogen atom by amino group. 6,7-Dialkyl-4-halo-1H-pyrrolo[3,4-c]pyridine-1,3(2H)-diimines were formed in analogous reaction at room temperature in the presence of potassium carbonate. 相似文献