排序方式: 共有158条查询结果,搜索用时 15 毫秒
101.
Dariya Semenyshyn Iryna Typilo Olha Sereda Oleg Dolomanov Helen Stoeckli-Evans 《ChemInform》2012,43(50):no-no
Good quality single crystals of the title compound are obtained by reaction of H4[Mo(CN)8] with the rare earth carbonates. 相似文献
102.
We study the structure of imaginary Verma modules induced from the"natural"Borel subalgebra of a toroidal Lie algebra. In particular, we establish a criterion of irreducibility for imaginary Verma modules and describe their submodules and irreducible quotients. We also describe the structure of Verma type modules in the case of sl(2)-toroidal Lie algebra over two variables. 相似文献
103.
We consider the homogenization of an elliptic spectral problem with a large potential stated in a thin cylinder with a locally periodic perforation. The size of the perforation gradually varies from point to point. We impose homogeneous Neumann boundary conditions on the boundary of perforation and on the lateral boundary of the cylinder. The presence of a large parameter 1/ε in front of the potential and the dependence of the perforation on the slow variable give rise to the effect of localization of the eigenfunctions. We show that the jth eigenfunction can be approximated by a scaled exponentially decaying function that is constructed in terms of the jth eigenfunction of a one-dimensional harmonic oscillator operator. 相似文献
104.
Domasevitch KV Solntsev PV Krautscheid H Zhylenko IS Rusanov EB Chernega AN 《Chemical communications (Cambridge, England)》2012,48(47):5847-5849
Domino cyclization of ketoenols and hydrazine leads to a series of polycondensed pyridazines, which reveal potential as rigid N-donor multidentate ligands for supramolecular synthesis of open coordination polymers. 相似文献
105.
Mugnaioli E Andrusenko I Schüler T Loges N Dinnebier RE Panthöfer M Tremel W Kolb U 《Angewandte Chemie (International ed. in English)》2012,51(28):7041-7045
"This is a mineral about which there has been much discussion" is a typical statement about vaterite in older standard textbooks of inorganic chemistry. This polymorph of CaCO(3) was first mentioned by H. Vater in 1897, plays key roles in weathering and biomineralization processes, but occurs only in the form of nanosized crystals, unsuitable for structure determination. Its structure could now be solved by automated electron diffraction tomography from 50 nm sized nanocrystals. 相似文献
106.
Garkusha I Fulara J Sarre PJ Maier JP 《The journal of physical chemistry. A》2011,115(40):10972-10978
Protonated pyrene and coronene have been isolated in 6 K neon matrixes. The cations were produced in the reaction of the parent aromatics with protonated ethanol in a hot-cathode discharge source, mass selected, and co-deposited with neon. Three electronic transitions of the most stable isomer of protonated pyrene and four of protonated coronene were recorded. The strongest, S(1) ← S(0) transitions, are in the visible region, with onset at 487.5 nm for protonated pyrene and 695.6 nm for protonated coronene. The corresponding neutrals were also observed. The absorptions were assigned on the basis of ab initio coupled-cluster and time-dependent density functional theory calculations. The astrophysical relevance of protonated polycyclic aromatic hydrocarbons is discussed. 相似文献
107.
We constructed a fundamental matrix of solutions of the Cauchy problem and studied its basic properties for a new class of
linear parabolic systems with smooth bounded variable coefficients that includes a class of the Shilov-type parabolic systems
of partial differential equations with nonnegative genus. 相似文献
108.
109.
Eugen P. Koval’chuk Oleksandr V. Reshetnyak Orest B. Pereviznyk Iryna E. Marchuk Vasyl Ya. Smetanets’kyj Jerzy B?a?ejowski 《Central European Journal of Chemistry》2010,8(3):652-661
The reaction of metals and glassy carbon with benzenediazonium tetrafluoroborate (BDFB) in aprotic solvents has been studied.
During contact of Pt, Au, Ag, Pd, or V with glassy carbon in concentrated diazonium salt solution no change of color was observed.
For Al, Ca, Cr, Cu, Fe, Ga, In, Mg, Li, Na, or Zn the process was accompanied by a rapid solution color change, rapid N2 release and the loss of metal sample mass. The copper metal ionization-dissolution was studied by ultraviolet and visible
absorption spectroscopy, along with gravimetric and volumetric measurements. A dissolution mechanism was proposed based on
kinetic, infrared, and X-ray diffraction data. The 432 nm absorption band appearing after Cu-BDFB reaction indicates formation
of the mixed complex [Cu(N2C6H5·(N≡C-CH3)3]+ where the copper atom is covalently bonded to the azophenyl radical and coordinated to acetonitrile (ACN). This complex is
thermodynamically unstable and decomposes slowly to a colorless crystalline and a black amorphous phase. The crystalline phase
was identified as [Cu(NC-CH3)4]BF4. The amorphous phase is a mixture of products formed by azophenyl and phenyl radical condensation.
相似文献
110.
Journal of Thermal Analysis and Calorimetry - Citrate precursors of copper, nickel and cobalt oxides, namely Cu(C6H7O7)2·5H2O, Ni(C6H7O7)2·2.5H2O and CoC6H6O7·6H2O, have been... 相似文献