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91.
R. I. Zainullina N. G. Bebenin V. V. Mashkautsan A. M. Burkhanov Yu. P. Sukhorukov V. V. Ustinov V. G. Vasil’ev B. V. Slobodin 《Physics of the Solid State》2000,42(2):292-297
An experimental study is reported of the temperature dependences of the electrical resistivity and magnetoresistance, thermal and magnetothermal EMF, the Hall effect, optical reflectance, sound velocity, and internal friction of polycrystalline lanthanum manganite La0.60Eu0.07Sr0.33MnO3 carried out within the 77–430-K temperature range. Substitution of a small amount of europium for lanthanum has been found to result in a considerable decrease in the resistivity and a change in the behavior of its temperature dependence. Four characteristic temperatures at which special features are observed in the above properties have been identified. The discussion of the conduction mechanisms involved is based on the concept of mobility edge motion. 相似文献
92.
Denisova L. T. Molokeev M. S. Galiakhmetova N. A. Denisov V. M. Vasil’ev G. V. 《Physics of the Solid State》2021,63(8):1159-1164
Physics of the Solid State - Titanates Bi2Pr2Ti3O12 and Bi2Nd2Ti3O12 have been obtained by the solid-phase synthesis using sequential annealing of the Bi2O3, Nd2O3, Pr6O11, and TiO2 stoichiometric... 相似文献
93.
E. M. Glebov V. P. Grivin D. B. Vasil’chenko A. V. Zadesenets V. F. Plyusnin 《High Energy Chemistry》2017,51(6):409-414
The two-quantum photochemistry of aqueous solutions of cis,trans-[PtIV(en)(I)2(CH3COO)2] (complex 1) has been studied by laser flash photolysis using an irradiation wavelength of 355 nm. This compound can be considered as a model representative of the mixed-ligand Pt(IV) complexes tested for use in photodynamic therapy. The appearance of transient absorption, presumably due to two consecutively produced Pt(III) complexes, has been revealed. The spectral and kinetic characteristics of the intermediates have been determined. A mechanism of two-quantum photolysis of complex 1 is proposed on the basis of the data obtained. 相似文献
94.
A. Yu. Vasil’kov D. A. Migulin A. V. Naumkin Ya. V. Zubavichus A. V. Budnikov O. G. Ellert Yu. V. Maksimov A. M. Muzafarov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2017,91(11):2188-2194
New hybrid materials based on Pt, Fe, and Pt–Fe nanoparticles stabilized in a matrix of polymethylsilsesquioxane nanogel and ultrahigh molecular weight polyethylene (UHMWPE) were prepared. Metal vapor synthesis was used to produce mono- and bimetallic nanoparticles. It was shown that organosilicon nanogel effectively stabilizes Pt nanoparticles with an average size of 0.9 nm. Using the nanogel results in the formation of superparamagnetic Fe particles 3–5 nm in size that consist of ferromagnetic Fe0 core and antiferromagnetic shells of Fe oxides. It is established that using an organosilicon matrix in the formation of Pt-Fe/UHMWPE systems helps reduce the average particle size of Fe in the material from 6.5 to 4.5 nm and narrow their particle size distribution. The composition, magnetic and electronic characteristics of the nanocomposites are studied via transmission electron microscopy, X-ray photoelectron spectroscopy, Mössbauer spectroscopy, XANES, and EXAFS. 相似文献
95.
E. I. Vasil’ev 《Fluid Dynamics》1998,33(4):604-611
The results of the numerical simulation of three problems of ideal gas flow with shock waves, which admit self-similar solutions,
are presented. These problems are the double Mach-type reflection of a shock from a wedge, the breakdown of a combined discontinuity
on a 90° sharp corner, and the outflow of a supersonic jet from an expanding slot. It is shown that for certain input data
the self-similar solution may become unstable and is replaced by a fluctuating flow. The reasons for the generation of these
fluctuations and their mechanism are discussed.
Volgograd. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 166–175, July–August,
1998. 相似文献
96.
P. I. Dem’yanov P. M. Poleshchuk I. P. Gloriozov A. Yu. Vasil’kov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(10):1731-1744
The structure of trans- and cis-conformers of bis(toluene)chromium(0) and the intramolecular interactions in them are studied by means of MP2 and density
functional theory along with topological and NBO analyses. It was concluded for the first time that the locations of two hydrogen
atoms of each methyl group between the phenyl ring planes in the most stable cis-conformer of bis(toluene)chromium(0) are largely determined by the stabilizing interactions of methyl C-H bonds and their
hydrogen atoms with the metal atom and chromium-carbon bonds. It was concluded from the obtained data that the C-H...Cr contacts
in the studied conformers should be considered as hydrogen bonds rather than agostic interactions. Contrary to the existing
conception of the quantum theory of atoms in molecules, repulsive interaction is shown to occur between the pairs of hydrogen
atoms of the two methyl groups in bis(toluene)chromium(0) cis-conformers rather than the stabilizing hydrogen-hydrogen interactions. 相似文献
97.
The molecular-mass distribution and amino acid composition of globular (albumin, lysozyme) and fibrillar (collagen) proteins
subjected to treatment in electron-beam plasmas of various gases were experimentally studied. The samples were treated in
the forms of powders and freeze-dried thin films. The electron-beam plasma treatment of powdered collagen resulted in the
formation of low-molecular-mass compounds only. The modification of albumin and lysozyme was accompanied by polymerization
of the proteins against the background of insignificant degradation. The plasma-stimulated processes occurred in the surface
layer of powder particles, whereas the bulk of the sample remained intact. The degradation and polymerization processes in
thin films of globular proteins occurred throughout the entire volume of the sample. 相似文献
98.
M. G. Voronkov A. A. Korlyukov É. A. Zelbst S. P. Knyazev I. M. Vasil rsev E. A. Chernyshev M. Yu. Antipin 《Journal of Structural Chemistry》2010,51(4):719-724
The crystal structures of anhydrous 1-germatranol and its complex with HCCl3 are centrosymmetrical dimers because of their intermolecular hydrogen bonds. In the germatranol crystal, the axial and equatorial
oxygen atoms of its two molecules are hydrogen bonded into an eight-membered coordination cycle. In the complex with HCCl3, the two molecules of germatranol are likewise linked in dimers, and both axial oxygen atoms are H bonded with HCCl3. In the investigated structures, the axial Ge—O bond is shorter than the equatorial ones. Depending on the number and strength
of the hydrogen bonds, the interatomic Ge—O and Ge ← N distances change markedly. The quantitative estimates of the H bond
energy are obtained from quantum chemical calculations of the model systems containing 1-germatranol and HCCl3 molecules. 相似文献
99.
M. Yu. Vasil’eva S. P. Fedorov D. A. Nikolaev I. I. Oleinik S. S. Ivanchev 《Polymer Science Series B》2010,52(7-8):443-449
The kinetic features of ethylene polymerization with six methylaluminoxane-activated bis(phenoxyimine) complexes of titanium chloride that are distinguished by the electronic properties of substituents in the phenoxy group are studied in the temperature range 30–80°C and at an ethylene pressure of 0.3 MPa. It is shown that, in the presence of an electro-donor or electron-acceptor substituent in the phenoxy group, the catalytic systems under study exhibit high activity (up to ~700 tPE mol cat ?1 mol ethylene ?1 h?1) and form high-molecular-mass PE samples (M η = (500–900) × 103) with different molecular-mass distributions. In the case of titanium bis(phenoxyimine) complexes containing donor substituents at the para position of the phenoxy group, the polymerization of ethylene follows the living-chain mechanism, while the introduction of acceptor substituents diminishes the contribution of this mechanism to the reaction. 相似文献
100.
Intensities of fundamental, overtone, and composite absorption bands for 11 olefins, 17 nitrogen- and oxygen-containing organic
compounds, and 12 sulfur-containing organic compounds are calculated in the anharmonic approximation. The first and second
derivatives of the electric dipole moment of a molecule were calculated by the quantum-chemical ab initio MP2/6-31G(1d) approach. It is shown that, for the studied compounds, the average contribution of overtones and composite frequencies to
absorption in the region from 100 to 4000 cm−1 is of about 10%. The major contribution (on the average 80%) of overtones and composite frequencies falls in the regions
(mainly from 1600 to 2800 cm−1) where fundamental transitions are rarely observed. The calculations well describe the centers and intensities of the fundamental,
overtone, and composite absorption bands and can be used for the standard-free spectrochemical determination of the compounds
of interest by their overtone spectra. 相似文献