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A thermodynamic analysis of the uniaxial stretching of polyurethanes of various compositions and mechanical histories was carried out by using deformation calorimetry. The initial small strain deformations were found to result from the volume elasticity of the hard phase. The intramolecular energy contributions of the soft blocks were estimated. The hard block contributions were shown to depend on their content and on the degree of sample stretching. The predominant role of the soft component is proved to be manifested only in softened samples with a hard block content not exceeding 30%. The thermodynamics of the softening and hysteresis phenomena were studied. The dependence of the deformation mechanism on the hard block content and mechanical history is discussed.The authors express their thanks to Dr. A. R. Korigodsky and Dr. M. P. Letunovsky for the PU samples. 相似文献
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Z. M. Vaisov I. A. Bessonova M. S. Yunusov A. I. Shreter 《Chemistry of Natural Compounds》1992,28(2):212-214
From the epigeal part of the previously unstudied plantAconitum sajanense we have isolated the new alkaloid acosanine, the structure of which has been established on the basis of spectral characteristics and has been confirmed by a direct comparison with a sample of demethyldelcorine.Institute of Chemistry of Plant Substances, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 247–249, March–April, 1992. 相似文献
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From the roots of the cultivated plant Aconitum paniculatum Lam. we have isolated a new diterpene alkaloid of the denudatine type, which we have called paniculamine and have established its structure by x-ray structural analysis (diffractometer, CuK= radiation, 1729 reflections, direct method, R = O. 055).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnylh Soedinenii, No. 2, pp. 277–282, March-April, 1995. Original article submitted November 15, 1994. 相似文献
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V. I. Akhmedzhanova I. A. Bessonova S. Yu. Yunusov 《Chemistry of Natural Compounds》1977,12(3):282-288
Summary 1. From the epigeal part of the plantH. perforatum growing in the Dzhungarian Ala-Tau we have isolated the lignane eudesmin, the known alkaloids evoxine, flindersine, and 7-isopentenyloxy--fagarine, and the new alkaloids haplamine, glycoperine, and methylevoxine. It has been shown that haplamine has the structure of 6-methoxyflindersine, glycoperine the structure of 7-hydroxy-4,8-dimethoxyfuranoquinoline 7-O--L-rhamnopyranoside, and methylevoxine the structure of 4,8-dimethoxy-7-(2-hydroxy-3-methoxy-3-methylbutoxy)furanoquinoline.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 320–328, May–June, 1976. 相似文献
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N. Batbayar D. Batsurén B. Tashkhodhaev V. I. Akhmedzhanova I. A. Bessonova M. R. Yagudaev 《Chemistry of Natural Compounds》1988,23(4):466-468
The spatial structure of the alkaloid kalidine obtained from the epigeal part ofKalidium gracile Fenzl. has been determined by IR and NMR spectroscopy and x-ray structural analysis. It has been established that it is the chloride of the trimethyl derivative of glycinamide.Institute of the Chemistry of Plant Substances of the Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 558–561, July–August, 1987. 相似文献
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V. I. Akhmedzhanova I. A. Bessonova S. Yu. Yunusov 《Chemistry of Natural Compounds》1979,14(4):404-406
Summary From the roots ofDictamnus angustifolius G. Don. collected in Chimgan at the end-of-fruit-bearing stage have been isolated alkaloids dictamnine, skimmianine, -fagarine, isodictamnine, isopteleine, and preskimmianine, the limonoid fraxinellone, and the steroid -sitosterol. This is the first time that any of these substances, with the exception of dictamnine and skimmianine, have been found in this plant.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 476–478, July–August, 1978. 相似文献