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1.
V. N. Kizhnyaev A. F. Pokatilov L. I. Vereshchagin L. V. Adamova A. P. Safronov A. I. Smirnov 《Russian Journal of Applied Chemistry》2006,79(7):1167-1173
Carbon-chain polymers with 1,3,4-oxadiazole rings were prepared by radical polymerization and polymer-analogous transformations. The kinetic relationships of the polymerization of vinyl-1,3,4-oxadiazole monomers and some properties of the resulting polymers were studied. The thermodynamics of interaction of poly-2-vinyl-5-methyl-1,3,4-oxadiazole, a nonionic water-soluble polymer, with water was examined. 相似文献
2.
L. I. Vereshchagin A. V. Petrov V. N. Kizhnyaev F. A. Pokatilov A. I. Smirnov 《Russian Journal of Organic Chemistry》2006,42(7):1049-1055
Nonfused bis-1,3,4-oxadiazoles were synthesized by reaction of 5-substituted mono-and bis-tetrazoles with mono-and dicarboxylic acid chlorides. The results of kinetic studies showed that the transformation of tetrazoles into 1,3,4-oxadiazoles is accelerated by 1 to 2 orders of magnitude on addition of a catalytic amount of dimethylformamide, triethylamine, or pyridine. 相似文献
3.
L. I. Vereshchagin A. V. Petrov A. G. Proidakov F. A. Pokatilov A. I. Smirnov V. N. Kizhnyaev 《Russian Journal of Organic Chemistry》2006,42(6):912-917
Polynuclear nonfused blocks containing 1,2,3-triazole, 1,3,4-oxadiazole, and tetrazole rings were synthesized by reaction of C-substituted tetrazoles with carboxylic acid chlorides, as well as by cycloaddition of 2-azidomethyl-1,3,4-oxadiazoles at the triple bond of acetylenic compounds. 相似文献
4.
Taking into account the tetrahedral shape of a quantum-dot quantum well (QDQW) when describing excitonic states, phonon modes, and the exciton-phonon interaction in the structure, we obtain within a nonadiabatic approach a quantitative interpretation of the photoluminescence spectrum of a single CdS/HgS/CdS QDQW. We find that the exciton ground state in a tetrahedral QDQW is bright, in contrast to the dark ground state for a spherical QDQW. The position of the phonon peaks in the photoluminescence spectrum is attributed to interface optical phonons. We also show that the experimental value of the Huang-Rhys parameter can be obtained only within the nonadiabatic theory of phonon-assisted transitions. 相似文献
5.
V. N. Kizhnyaev L. V. Adamova F. A. Pokatilov E. A. Krakhotkina T. L. Petrova A. I. Smirnov 《Polymer Science Series A》2009,51(2):168-173
The thermodynamics of interaction with water and the behavior of 5-vinyltetrazole copolymers with comonomers of different chemical natures and hydrophilicities in aqueous media have been studied. It has been shown that the presence of side perfluoroalkyl and disubstituted tetrazole fragments, which ensure a strong self-association of polymer chains in copolymer macromolecules, favors a greater decrease in water affinity of polymers compared to the effect of hydrophobic alkyl substituents. 相似文献
6.
Synthesis of polynuclear heterocyclic polynitrogen systems based on cyanuric chloride and its derivatives 总被引:1,自引:0,他引:1
L. I. Vereshchagin O. N. Verkhozina F. A. Pokatilov A. G. Proidakov V. N. Kizhnyaev 《Chemistry of Heterocyclic Compounds》2010,46(2):206-211
Polynuclear structures containing several heterocycles of various types were synthesized by the reaction of cyanuric chloride
and its mono- and dichloro derivatives with triazoles and tetrazoles in the presence of bases. 相似文献
7.
V. S. Pokatilov 《Physics of the Solid State》2006,48(8):1521-1525
The hyperfine fields B 0, enhancement factors η, and transverse relaxation times T 2 for 139La nuclei in La0.75Sr0.25CoO3 and La0.5Sr0.5CoO3 perovskites at 4.2 K are measured by pulsed nuclear magnetic resonance spectroscopy. The hyperfine coupling constants P for 139La nuclei in the perovskites under investigation do not depend on the composition or the crystal lattice type. The local anisotropy fields are evaluated from the data on the enhancement factor η. The dependence of the echo amplitude decay on the delay time τ of the second radio-frequency pulse does not exhibit an exponential behavior. The amplitude decay rate increases with an increase in the delay time τ. This suggests that the Suhl-Nakamura interaction contributes to the transverse relaxation time T 2. 相似文献
8.
V. N. Kizhnyaev E. A. Krakhotkina T. L. Petrova M. V. Kazantseva F. A. Pokatilov O. N. Verkhozina 《Polymer Science Series B》2011,53(3-4):144-150
High-molecular-mass compounds (ionenes) containing charged imidazole and 1,2,4-triazole rings in the main chain are synthesized via the reaction of dihaloalkanes with bis(azoles) of various structures. It is shown that azole-containing ionenes can be involved in interpolymer reactions with negatively charged polyelectrolytes (polyacrylic acid and heparin) to form soluble and insoluble polyelectrolyte complexes of various compositions. The results confirm a potentially high antiheparin activity of azole-containing ionenes. 相似文献
9.
V. S. Pokatilov A. S. Sigov A. O. Konovalova 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(3):347-351
Pulse nuclear magnetic resonance (NMR) was applied in studying the effect of 57Fe isotope content in multiferroic BiFeO3 on the shape of NMR spectra at 4.2 K. Strong dependences of the NMR line shape on the isotope content and transverse relaxation time were found. Consideration of these effects on NMR line shape shows that there is an undisturbed (with no anharmonicity effect) space spin-modulated structure of the cycloid type in BiFeO3. The Mössbauer effect was also used to investigate the perovskite BiFeO3 at 650, 295, and 87 K. Experimental spectra allowed us to obtain the distribution of hyperfine fields, which was found to be consistent with studies of the NMR line shape. The local electronic and magnetic states of the iron ion were measured. 相似文献
10.
The effects of the 57Fe isotope content and high-frequency magnetic field amplitude h
1 on the shape of the NMR spectrum of multiferroic BiFeO3 at T = 4.2 K are studied by pulsed nuclear magnetic resonance. The NMR spectrum shape and transverse relaxation time T
2 are found to depend strongly on the 57Fe isotope content and h
1 in multiferroic BiFeO3 in the presence of a spatial spin-modulated structure of a cycloid type. In a sample with a high 57Fe isotope content, the Suhl-Nakamura interaction contributes substantially to T
2. When these dynamic effects are taken into account for analysis of the NMR spectrum shape, an undisturbed (without an anharmonicity
effect) spatial spin-modulated structure of a cycloid type is shown to exist in BiFeO3. 相似文献