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排序方式: 共有1993条查询结果,搜索用时 62 毫秒
31.
An expression for electron transfer rate has been obtained through the solution of a time wave equation by the variational method by defining the wave function as a linear combination of functions corresponding to electron localization on the donor and on the acceptor. A dependence of electron transfer on temperature, on the electronic and vibrational characteristics of the system has been derived. An activation energy temperature-variation effect has been obtained. It has been proved that many-electron transfers are impossible. 相似文献
32.
L. A. Petrov N. P. Lobanova V. L. Volkov G. S. Zakharova I. P. Kolenko L. Yu. Buldakova 《Russian Chemical Bulletin》1989,38(9):1806-1809
Polyvanadomolybdic acids catalyze the process of peracid oxidation of 1,2,4-trimethylbenzene. The selectivity with respect to 2,3,5-trimethyl-1,4-benzoquinone increases with increasing degree of replacement of vanadium atoms in the PVMA by molybdenum; this is related to increased stability of the intermediate peroxides of the heteropolyvanadates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1967–1969, September, 1989. 相似文献
33.
The title compound has been studied by an X-ray structure analysis (a CAD-4 diffractometer, MoK, graphite monochromator, /2 scan, 2
max, direct methods, 884 reflections R=0.0416). The crystals are orthorhombic with a=20.326, b=8.828, c=7.3872 Å, V=1325.6 Å3, and Z=4. C8H18B9N, space group Pnam, dcalc=1.130 g/cm3, dexp=1.130 g/cm3. The compound is a molecular complex. The main feature of its crystal structure is the coexistence of two asymmetric mirror isomers which have the same pyridine cycle and the same atoms of the carborane skeleton (excluding C7, H7C, and H34). The methyl group has a disordered orientation in two positions. The complexes are linked by van der Waals interactions.Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 4, pp. 149–153, July–August, 1993.Translated by T. Yudanova 相似文献
34.
K. A. Volkova A. N. Nikol'skaya E. P. Levanova A. N. Volkov B. A. Trofimov 《Chemistry of Heterocyclic Compounds》1979,15(12):1296-1298
Alkylthio-substituted dienic 1,3-dioxolan-2-ones and bis(4,4-diorganyl-5-methyli-dene-1,3-dioxolan-2-ones) were obtained in high yields by the reaction of 2-methyl-6-alkylthio-5-hexen-3-yn-2-ols and tertiary diacetylenic glycols with carbon dioxide under pressure in the presence of catalytic amounts of triethylamine and monovalent copper salts.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1617–1619, December, 1979.Original article submitted January 24, 1979. 相似文献
35.
Kotov V. V. D'yakonova O. V. Sokolova S. A. Volkov V. I. 《Russian Journal of Electrochemistry》2002,38(8):888-891
The transport of water molecules and the distribution of functional groups in polyamidoacid carboxyl-containing cation-exchange membranes based on pyromellitic acid are studied by NMR and ESR techniques. It is shown that the self-diffusion coefficients of water differ in the gel and intergel regions. Structural parameters of conducting channels in the gel regions are determined. In electrodialysis of one-component and binary solutions, polyamidoacid membranes possess higher transport numbers and separation coefficients of counterions that are less hydrated in solution. 相似文献
36.
Crystal structure of di (1-n-dodecylpyridine) decahydro-closo-decaborate(2-) (C5H5N-C12H25)2[B10H10]
A. V. Virovets N. N. Vakulenko V. V. Volkov N. V. Podberezskaya 《Journal of Structural Chemistry》1994,35(3):339-344
Using X-ray analysis, we have determined the crystal structure of di(1-n-dodecylpyridine) decahydrocloso-decaborate(2-), (py-C12H25)2[B10H10] (I), a yellow salt-like substance obtained by reaction of (py-C12H25)Br and K2[B10H10] in an aqueous solution. Compound I melts at 1250 without decomposition and luminesces under ultraviolet radiation (λmax=555 nm at 298 K). In I, quaternary pyridine bases, containing a hydrocarbon radical with the C12 chain, are combined with the closo-cluster hydroborate anion [B10H10]2-. This results in a charge transfer structure having shortened nonvalent (equatorial B) H.…H(C of pyridine) contacts of 2.41(8) Å. Crystals I are orthorhombic with a=8.584 (1), b=7.739(1), c=31.183(5) Å, Vcell=2071.4(5) Å3, space group Pnmm, Z=2, dcalc=0.986 g/cm3 (a Syntex P21 automatic diffractometer, λCUKα, Nmsd/used=1654/711, Raniso=0.076, Rw=0.080, w=1/(σ(Fobs)2+0.0007·F obs 2 ). Substantial changes are observed in the vibration range of the valent B?H bonds in the IR spectrum of I as compared to that of pure ionic K2[B10H10], confirming the interaction. 相似文献
37.
Formation of large-scale hydrodynamic convective patterns in plasma-like current-carrying media is considered. This process is shown to be described by the same equations, as Benard rolls, except that a temperature field must be replaced by a magnetic field. A simple low-mode model of spatial pattern formation for a case of cylindrical liquid-metal conductor with current is proposed and investigated. Nonlinear interaction of perturbations of the magnetic field and the velocity field results in an increase of effective conductor resistance even when transport coefficients are constant. In our opinion, it is this instability, that is of first importance at the initial stages of the electric explosion of conductors. In particular, it leads to conductor stratification and electric current interruption. (c) 1996 American Institute of Physics. 相似文献
38.
39.
T. A. Mirnaya V. V. Trachevskii S. V. Volkov Yu. V. Bereznitsxmkii 《Theoretical and Experimental Chemistry》1994,29(1):59-62
The dependence of NMR spectra of 7Li, 23Na, 133Cs and of the conductivity of melts of lithium, sodium, and cesium alkanoates in melts of alkanoic acids on the length of the aliphatic chain of the anion has been studied. As the anion size increases, chemical shifts of 23Na and 133Cs nuclei toward weak fields and 7Li nuclei toward strong fields are observed. The nature of the chemical shifts of alkali metal nuclei and of the electricity transport characteristic in the studied systems is discussed in connection with the nature of cation-anion interactions and the size and degree of free rotation of the anion.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 29, No. 1, pp. 81–87, January–February, 1993. 相似文献
40.
E. A. Il'inchik T. M. Polyanskaya M. K. Drozdova K. G. Myakishev V. N. Ikorskii V. V. Volkov 《Russian Journal of General Chemistry》2005,75(10):1545-1552
[Tris(1,10-phenanthroline)manganese](2+) 1,2;1′,2′-trans-bis[nonahydro-closo-decaborate](2?) bis(dimethylformamide) containing the complex anion [MnPhen3]2+ with the paramagnetic central Mn atom and the [B20H18]2? anion formed by fusion of two closo clusters B10H9 was synthesized and characterized by single crystal X-ray diffraction and by IR, X-ray photoelectron, and Raman spectroscopy. 相似文献