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51.
52.
Bogatyrev V. M. Borisenko N. V. Pokrovskii V. A. 《Russian Journal of Applied Chemistry》2001,74(5):839-844
Thermal degradation of polyvinylpyrrolidone was studied by thermogravimetry, IR spectroscopy, and thermal-desorption mass spectrometry. 相似文献
53.
T. A. Vaganova L. M. Pokrovskii V. D. Shteingarts 《Russian Journal of Organic Chemistry》2001,37(1):62-66
Reduction of 9,10-dicyanoanthracene with one equivalent of metallic potassium in liquid ammonia at -33°C gives a product which almost does not react with butyl bromide. By contrast, the two-electron reduction product reacts with butyl bromide to form, depending on the reaction conditions and procedure for treatment of the reaction mixture, one of the three compounds: 10-butyl-9-cyanoanthracene, 10-butyl-10-cyano-9,10-dihydroanthracen-9-one, or 9,10-dibutyl-9,10-dicyano-9,10-dihydroanthracene. Relatively stable 10-butyl-9,10-dicyano-9,10-dihydro-9-anthryl anion was presumed to be a common precursor of these products. 相似文献
54.
Features have been observed in the current dependences of the torsion angle, φ(I), for samples of a quasi-one-dimensional conductor TaS3 irradiated by a high-frequency (HF) field. The features appear at the same current values as the Shapiro steps on the current-voltage
characteristics, i.e., correspond to the synchronization of the motion of a charge-density wave (CDW) by the HF field. The
shape of the features in the φ(I) dependences indicates a decrease in the inhomogeneous deformation of the CDW under the synchronization conditions. The investigation
of torsion appears to be a highly sensitive method for determining the spatial coherence of the CDW. 相似文献
55.
Yu. M. Lipnitskii V. A. Platonov A. N. Pokrovskii V. N. Sirenko V. N. Shmanenkov 《Fluid Dynamics》1983,18(3):379-384
A study is made of the influence of the boundary layer on the unsteady aerodynamic characteristics of blunt cones oscillating in a supersonic gas stream about zero angle of attack. A solution to the problem is constructed in the framework of the linear theory of bodies of finite thickness. Such an approach has been used [1–3] in the case of the equations of motion of an ideal gas to calculate the unsteady aerodynamic characteristics of sharp and blunt bodies of various configurations. The influence on these characteristics of the viscosity effects due to the presence on the surface of the body of a laminar boundary layer has been taken into account [4–6] for bodies of the simplest shapes (wedge, cone). The present paper considers the unsteady aerodynamic characteristics of cones and investigates the influence of rounding of the tips and laminar and turbulent flow regimes in the boundary layer. 相似文献
56.
I. G. Gorlova V. Ya. Pokrovskii S. G. Zybtsev A. N. Titov V. N. Timofeev 《Journal of Experimental and Theoretical Physics》2010,111(2):298-303
The structure and transport properties of single crystal whiskers of the TiS3 quasi-one-dimensional semiconductor have been investigated. The anisotropy of the conductivity in the plane of layers (ab) has been measured as a function of the temperature. The anisotropy at 300 K is 5 and increases with a decrease in the temperature.
Features on the temperature dependences of the conductivity along and across the chains are observed at 59 and 17 K. Near
the same temperatures the form of the current-voltage characteristics measured along the chains is qualitatively changed.
The current-voltage characteristics below 60 K exhibit nonlinearity and have a threshold form below 10 K. The results indicate
possible phase transitions and the collective conduction mechanism at low temperatures. 相似文献
57.
M. E. Rakhmanova O. A. Luzina M. A. Pokrovskii A. G. Pokrovskii N. F. Salakhutdinov 《Russian Chemical Bulletin》2016,65(2):566-569
Cyanoethyl derivatives of usnic acid (natural lichen metabolite) were prepared. The reaction proceeded as a C-alkylation process via addition of two acrylonitrile molecules. Cytotoxic effect of the synthesized derivatives on the blood tumor cell lines was studied. 相似文献
58.
Aleksej Goduljan Dr. Leandro Moreira de Campos Pinto Dr. Fernanda Juarez Dr. Elizabeth Santos Prof. Dr. Wolfgang Schmickler 《Chemphyschem》2016,17(4):500-505
Silver is much more reactive to oxygen than gold; nevertheless, in alkaline solutions, the rates of oxygen reduction on both metals are similar. To explain this phenomenon, the first, rate‐determining step of oxygen reduction on Ag(100) is determined by a combination of DFT, molecular dynamics, and electrocatalysis theory. In vacuum, oxygen is adsorbed on Ag(100), but in the electrochemical environment, the adsorption energy is offset by the loss of hydration energy as the molecule approaches the surface. As a result, the first electron transfer should take place in an outer‐sphere mode. Previously, the same mechanism for oxygen reduction on Au(100) has been predicted, and these calculations have been repeated by using a more advanced version of the electrocatalysis theory discussed herein to confirm previous conclusions. The theoretical results compare well with experimental data. 相似文献
59.
60.
The review article is devoted to the mass spectrometry method of ionization of material by fast atom bombardment (FAB). The FAB method extends the possibilities of mass spectrometry by making it possible to obtain the mass spectra of nonvolatile, thermally unstable, and high-polarity compounds, which contain information on the molecular weight and the structure of the compounds studied. The mechanism of ion formation, the apparatus design, and also the main results of FAB mass spectrometric study of different classes of compounds are examined. This method is specially helpful in analysis of natural compounds.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 1, pp. 62–78, January, 1987. 相似文献