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1.
R. K. Potapova 《Acoustical Physics》2002,48(4):486-493
Modern language studies are characterized by a variety of forms, ways, and methods of their development. In this connection, it is necessary to specify the problem of the development of their internal differentiation and classification, which lead to the formation of specific areas knowledge. An example of such an area is speechology—a field of science belonging to fundamental, theoretical, and applied linguistics. 相似文献
2.
V. D. Kiselev G. G. Iskhakova E. A. Kashaeva L. N. Potapova A. I. Konovalov 《Russian Chemical Bulletin》2004,53(11):2490-2495
The densities of anthracene, tetracyanoethylene, maleic anhydride, N-phenylmaleineimide, trans, trans-1,4-diphenylbuta-1,3-diene, and their Diels-Alder adducts were measured in the solid state and in solution at 25 °C. The reaction volumes in the solid state were calculated from the difference in molar volumes. They turned out to be low, close to each other (–4 to –11 cm3 mol–1), and slightly different from the reaction volumes (–8±1 cm3 mol–1) calculated from the van der Waals radii. The reaction volumes in solutions (–15 to –32 cm3 mol–1) were found from the difference in partial molar volumes of the reactants in dioxane, acetonitrile, and 1,2-dichloroethane, The experimental Diels-Alder reaction volumes in solution are determined not only by the formation of new bonds in an adduct: a considerably higher contribution (to 75%) is made by a change in the volume of intermolecular empty spaces in solution on going from reactants to adducts.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2386–2390, November, 2004. 相似文献
3.
Reaction of tricrotylborane with 1-pyrroline proceeds stereoselectively to give (1R
*
,1′S
*
)-2-(1-methylallyl)pyrrolidine. The latter was converted to the pyrrolizidine alkaloid (±)-pseudoheliotridane through hydroboration-oxidation-intramolecular
cyclization.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1450–1452, July, 1998. 相似文献
4.
V. I. Kovalenko L. I. Maklakov E. I. Borisoglebskaya L. I. Potapova E. A. Shokova I. M. Vatsouro V. V. Kovalev 《Russian Chemical Bulletin》2007,56(6):1103-1109
Based on the Fourier transform IR spectroscopy together with the published NMR and X-ray data, it was shown that cyclic co-operative
intramolecular hydrogen bond in calix[n]arene (n = 4, 6, 8) molecules is mainly responsible for their conformational state irrespective of the presence or absence of bulky
substituents at the upper rim of the molecules. In accordance with the size of a macrocycle (n = 4, 6, 8), the stable conformation, secured by such a hydrogen bond, constitutes a cone, a pinched cone, and a pleated loop, respectively. The new, potentially competing system of hydrogen bonds in calix[6]arenes with 3-carboxymethyl-1-adamantyl
substituents does not affect the conformational state of the macrocycle and its H-bonding. Six carboxy groups at the upper
rim form in pairs three cyclic dimers, which does not disturb the hydrogen bonds of the hydroxy groups and the conformation
of the macrocycle. In addition, the cavity of the molecule is considerably enlarged. The removal or rearrangement of the guest
molecules in the solid calixarene by heating up to 180 °C only slightly affects the conformational state of macrocycles bearing
bulky substituents, whereas in calixarenes devoid of such substituents, the similar procedure leads to somewhat of a distortion
of the macrocycles (judging from the IR spectral indications of hydrogen bonding).
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1062–1068, June, 2007. 相似文献
5.
M. E. Gurskii K. A. Lyssenko A. L. Karionova P. A. Belyakov T. V. Potapova M. Yu. Antipin Yu. N. Bubnov 《Russian Chemical Bulletin》2004,53(9):1963-1977
The conformational equilibrium in solution was examined by NMR spectroscopy for a series of 7-phenyl-3-borabicyclo[3.3.1]nonane derivatives containing various substituents at the boron atom. The structures of these derivatives were studied in the crystalline state (X-ray diffraction analysis) and by quantum-chemical calculations (B3Pw91/6-31G*). The B...Ph transannular interactions corresponding to charge transfer from the system of the phenyl group to the vacant p-orbital of the B atom were demonstrated to be responsible for unique stability of the chair-chair conformation of these derivatives.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1884–1896, September, 2004. 相似文献
6.
7.
Yu. G. Yegiazarov M. F. Gorbatsevich Ye. N. Yermolenko L. L. Potapova A. Yu. Volodin B. Kh. Cherches A. A. Shunkevich V. V. Korotkevich 《Kinetics and Catalysis》2011,52(4):540-546
A procedure for the preparation of a fibrous palladium-containing catalyst for the removal of dissolved oxygen from water
was developed. This procedure includes the preliminary modification of an anionexchanger fiber with carboxylate ions, which
makes it possible to localize metal clusters in a thin subsurface layer of a fiber at the subsequent stages of the ion-exchange
introduction of palladium into the carrier and the reduction of palladium. It was found that the higher activity of fibrous
palladium-containing catalysts based on the citrate forms of anion exchangers, as compared with that of samples based on the
chloride forms, was due to the predominant arrangement of reduced metal clusters on the external surface and an adjacent thin
layer of the fiber. 相似文献
8.
9.
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