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991.
992.
I. Yu. Fedorov 《Mathematical Notes》1998,63(6):796-801
A representation of the anticanonical K3 surface of a singular pencil of conics is described. This generalizes the well-known Shokurov theorem.Translated fromMatematicheskie Zametki, Vol. 63, No. 6, pp. 903–910, June, 1998.The author is greatly indebted to V. A. Iskovskikh, Yu. G. Prokhorov, and I. A. Chel'tsov for fruitful discussions.This research was supported by the Russian Foundation for Basic Research under grant No. 96-01-00820 and by INTAS under grant No. 93-2805.00-00-00. 相似文献
993.
O. V. Almjasheva A. V. Smirnov B. A. Fedorov M. V. Tomkovich V. V. Gusarov 《Russian Journal of General Chemistry》2014,84(5):804-809
We synthesized nanoparticles of variable composition based on zirconium dioxide in the ZrO2-Y2O3 (or Gd2O3)-H2O systems under hydrothermal conditions. By X-ray diffraction and small-angle X-ray scattering studies revealed that the nanoparticles consist of crystalline core and amorphous shell. Increase of Y2O3 (or Gd2O3) content yields increases of shell size and decreases of core size. The effect is due to suppressed ZrO2 crystallites growth caused by development of the shell preventing zirconium ions transport. 相似文献
994.
Analytic first and second derivatives of the energy are developed for the fragment molecular orbital method interfaced with molecular mechanics in the electrostatic embedding scheme at the level of Hartree-Fock and density functional theory. The importance of the orbital response terms is demonstrated. The role of electrostatic embedding upon molecular vibrations is analyzed, comparing force field and quantum mechanical treatments for an ionic liquid and a solvated protein. The method is applied for 100 protein conformations sampled in molecular dynamics (MD) to take into account the complexity of a flexible protein structure in solution, and a good agreement with experimental data is obtained: Frequencies from an experimental infrared (IR) spectrum are reproduced within 17 cm−1 . 相似文献
995.
I. Ya. Zaitseva I. S. Kovaleva V. A. Fedorov 《Russian Journal of Inorganic Chemistry》2014,59(11):1340-1342
The interaction in the HgBr2-CdBr2-PbBr2 ternary system was studied by differential thermal analysis; the isoconcentration section of the system at 50 mol % CdBr2 was investigated. Based on the results of the study, a projection of the liquidus surface of the HgBr2-CdBr2-PbBr2 ternary system to the composition triangle was constructed; the boundaries of the primary crystallization fields were determined for three phases: HgBr2 (degenerate field), solid solution α based on CdBr2, and solid solution β based on PbBr2; and isotherms were drawn. A ternary eutectic has the composition 93 mol % HgBr2-1 mol % CdBr2-6 mol % PbBr2 and melts at 235°C. 相似文献
996.
I. Ya. Zaitseva I. S. Kovaleva V. A. Fedorov 《Russian Journal of Inorganic Chemistry》2014,59(2):122-125
Phase equilibria in the CsBr-Cs2ZnBr4-Cs2CdBr4-Cs2HgBr4 quaternary system were studied by differential thermal analysis. The CsBr-Cs2ZnBr4-Cs2HgBr4 ternary system has a ternary eutectic, E 1, at ~83 mol % Cs2HgBr4, 2 mol % Cs2ZnBr4, and 15 mol % CsBr with a melting point of ~415°C. The CsBr-Cs2ZnBr4-Cs2CdBr4 ternary system has a ternary eutectic, E 2, at ~53.5 mol % Cs2CdBr4, 1.5 mol % Cs2ZnBr4, and 45 mol % CsBr with a melting point of ~450°C. The polythermal section Cs3ZnBr5-Cs2CdBr4-Cs2HgBr4 in the CsBr-Cs2ZnBr4-Cs2CdBr4-Cs2HgBr4 quaternary system was constructed and investigated. This section is a quasi-ternary system and is characterized by the formation of regions of solid solutions Cs2Zn x Cd y Hg1?x ? y Br4 and solid solutions based on Cs3ZnBr5. The liquidus surface of the quaternary system consists of three fields of primary crystallization of cesium bromide, a solid solution Cs2Zn x Cd y Hg1?x ? y Br4, and a solid solution based on Cs3ZnBr5. 相似文献
997.
I. Ya. Zaitseva I. S. Kovaleva V. A. Fedorov 《Russian Journal of Inorganic Chemistry》2013,58(8):898-900
The phase diagram of the PbBr2-BaBr2 system over the entire concentration range is studied for the first time by differential thermal analysis and X-ray powder diffraction analysis. No new compounds are formed in the system. The phase diagram is represented by a continuous series of solid solutions (type I by Rooseboom’s classification). The unit cell parameters change as a linear function of composition. 相似文献
998.
N. V. Fedorov A. V. Anisimov E. A. Viktorova 《Chemistry of Heterocyclic Compounds》1989,25(12):1356-1359
2,3-Dihydronaphtho[1,2-b]thiophene 1-oxides, obtained by thermolysis of alkyl 1-naphthyl sulfoxides, are reduced by lithium aluminum hydride to 2,3-dihydronaphtho [1,2-b]thiophenes, whereas under the influence of acetic and trifluoroacetic anhydrides they form naphtho[1,2-b]thiophenes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1629–1633, December, 1989. 相似文献
999.
A. A. Kuzubov N. S. Eliseeva P. O. Krasnov F. N. Tomilin A. S. Fedorov A. V. Tolstaya 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(8):1332-1335
The geometrical characteristics of a 2D SiC monolayer on Mg(0001) and MgO(111) plates regarded as potential materials for growing two-dimensional silicon carbide were studied. The most favorable positions of the atoms of 2D SiC on the substrates were determined. In the 2D SiC/Mg(0001) system, unlike in 2D SiC/MgO(111), the deviation of the carbon atom from the silicon carbide monolayer was insignificant (0.08 Å). Consequently, magnesium can be used as a substrate for growing two-dimensional silicon carbide. The use of MgO(111) is not recommended because of a significant distortion of the 2D SiC surface. 相似文献
1000.
Bukhvalova S. Yu. Maleev A. A. Gracheva Yu. A. Voitovich Yu. V. Ignatov S. K. Svirshchevskaya E. V. Fedorov A. Yu. 《Russian Chemical Bulletin》2019,68(12):2205-2215
Russian Chemical Bulletin - New allocolchicine derivatives bearing 2,3-dihydrobenzo[b]oxepine moiety were synthesized via gold-catalyzed cyclization as a key synthetic step. The obtained... 相似文献