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991.
992.
G. I. Koldobskii Yu. E. Myznikov A. B. Zhivich V. A. Ostrovskii V. S. Poplavskii 《Chemistry of Heterocyclic Compounds》1992,28(6):626-631
In this review we discuss results obtained in the development of methods for the synthesis of tetrazoles and tetrazolium salts together with studies of alkylation, acylation, and imidoylation of tetrazole and 5-substituted tetrazoles under conditions of phase-transfer catalysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 754–761, June, 1992. 相似文献
993.
Yu. V. Zhitnikov Yu. I. Zetser 《Journal of Applied Mechanics and Technical Physics》1992,33(6):787-792
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 6, pp. 22–28, November–December, 1992. 相似文献
994.
Main chain liquid crystal polymers are modelled as either worms or jointed rods. In reality they are composed of mesogenic units (rods) linked by spacers with varying degrees of flexibility. We present a molecular model to describe non-homogeneous nematic polymers. The model takes account of molecular parameters, such as the lengths of the mesogenic group and the spacer units, and the interactions between them. The spacers are found to have an order differing from the mesogenic units. If the spacer is not very long and thus in effect is inflexible, one end of the spacer can retain to some extent the orientation of the other end, allowing orientational correlation between spacers mediated by the intermediate mesogenic unit. This is important in giving the chain a global rod-like behaviour as the nematic field becomes strong or the temperature low. The nematic order of the two components (mesogens and spacers), the nematic-isotropic transition as well as the latent entropy are examined. Furthermore, the anisotropic conformations of the polymers are investigated, which show either rod-like or random walk behaviour. Comparison of our results with experiment is found to be satisfactory. 相似文献
995.
S. Z. Levendorskiî 《Siberian Mathematical Journal》1992,33(5):826-834
Rostov-on-Don. Translated fromSibirskiî Matematicheskiî Zhurnal, Vol. 33, No. 5, pp. 91–99, September–October, 1992. 相似文献
996.
997.
本文以金属指示剂甲基百里(香)酚蓝作为鳌合剂制得具有相应鳌合基团的负载树脂.研究了该树脂的某些分析特性及其在富集天然水中微量铜、钻、镍、锌中的应用. 相似文献
998.
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 6, pp. 96–103, November–December, 1992. 相似文献
999.
V. I. Kulik E. V. Meshkov A. S. Nilov Z. T. Upitis 《Mechanics of Composite Materials》1991,27(2):159-166
1000.
V.V. Glushkov S.V. Demishev M.I. Ignatov Yu.B. Paderno N.Yu. Shitsevalova O.A. Churkin N.E. Sluchanko 《Journal of solid state chemistry》2006,179(9):2871-2874
In order to reveal the nature of the ground state of archetypal intermediate-valence compound SmB6, a comprehensive study of its transport and magnetic properties was carried out on high-quality single crystals at temperatures of 1.8-300 K in magnetic fields up to 7 T. A drastic enhancement of negative magnetoresistance was observed below 14 K, with the maximum absolute value of Δρ/ρB2∼2.2×10−3 T−2 at T≈5.2 K. This effect seems to be attributable to anomalous magnetic scattering of many-body (exciton-polaronic) complexes induced by fast valence fluctuations on Sm sites. The observed anomalies of magnetotransport, thermoelectric and magnetic characteristics are discussed in terms of electron phase transition to the coherent state of interacting many-body complexes occurring at T*∼5 K. 相似文献