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51.
Guang Xing WANG Jing Xin ZHANG Shu Feng CHEN Xiao Tian LIANG* Institute of Materia Medica Chinese Academy of Medical Sciences Peking Union Medical College Beijing 《中国化学快报》2001,(3)
Chrysotricine 1 was isolated from the Chinese herb medicine Hedyotis Chrysotricha and was shown to possess antitumor activity1. Its structure has been elucidated as a novel zwitterionic (-carboline alkaloid containing a 2,2,5-trisubstituted tetrahydrofuranyl group. The (-carboline compounds have attracted considerable attraction in recent years because of their promising and intriguing biological activities2. Recently, we have established the absolute configuration of chrysotricine by the fir… 相似文献
52.
Li Yuan MOU Zi Yun LIN Li Ya ZHU* Xiao Tian LIANG Institute of Materia Medica Chinese Academy of Medical Sciencesand Peking Union Medical College Beijing Center for Biophysical Science Engineering University of Alabama at Birmingham 《中国化学快报》2001,(6)
Mannich reaction is widely used for the synthesis of many kinds of compounds1. In the synthesis of the derivatives of styryl ketonic Mannich bases, a one-pot method is used, in which ketone, secondary-amine hydrochloride, paraformaldehyde are refluxed together in alcohol2,3. In most cases the normal Mannich product MA is obtained. But when certain amine is used as the reactant, a side-product IM, instead of MA is obtained. MS and 1HNMR data indicate that compound IM is a new type of Man… 相似文献
53.
Wen Yan HU Wen Ping XU Jian Gong SHI* Yong Chun YANG Guang Xiong ZHOU Institute of Materia Medica Chinese Academy of Medical Sciences Peking Union Medical College Bejing Hospital of Jiu Quan District Gansu Province Jiuquan Dis 《中国化学快报》2001,(9)
Alangium, the sole genus in the family Alangiaceae, has a variety of about 20 species distributed in the tropical and subtropical area of the Eastern Hemisphere, and 13 species are known to occur in the south of China1. A. plantanifolium and A. chinense are used in chinese traditional medicine for the treatment of rheumatalgia, paralysis, cardianeuria, and wound2. Pharmacological studies of the extracts of these two species showed muscular relaxing activity, and anabasine was considered as t… 相似文献
54.
聚乙烯吡咯烷酮中纳米邻苯二甲酸铽络合物的不寻常荧光特性 总被引:3,自引:0,他引:3
本文以聚乙烯吡咯烷酮为基质制得了纳米邻苯二甲酸铽络合物并对其荧光光谱进行了研究 ,结果表明聚乙烯吡咯烷酮中纳米邻苯二甲酸铽络合物主要荧光发射峰的相对强度及峰的半高宽有明显变化 ,并且主峰附近分化出两个峰。 相似文献
55.
56.
剪切变形下非晶态高聚物的力学行为 总被引:1,自引:0,他引:1
基于非平衡态热力学理论,提出了一个适用于不可压材料的新的热粘弹性本构模型.该模型将橡胶弹性理论中的非高斯分子网络模型推广到计及粘性和热效应的情形.通过引入一组二阶张量形式的内变量,建议了一个新的Helmholtz自由能表达式,从而可以用来合理描述内变量的演化规律.根据以上模型,重点研究了热粘弹性材料在简单剪切变形下的力学行为,考察了由于分子链取向分布的变化而产生的“粘性耗散诱导”各向异性,讨论了应变率效应和由于粘性耗散而导致的热软化效应对剪应力的影响.理论预测结果与G’Sell等人的实验数据的定性比较表明了新的本构模型的有效性。 相似文献
57.
Introduction It was reported that stilbene monomers showed multi-faced biological activities, such as antioxidation, antimutagen, antibacterial, antifungal activities.1 Espe-cially, isorhapontigenin and resveratrol showed potent inhibition on biosynthesis of leukotriene and its receptor antagonist.2 Some oligostilbenes exhibited more potent bioactivities than their monomers.3 In recent years, a number of oligostilbenes were isolated from natural sources, but a few of studies on their pharmacol… 相似文献
58.
贾淑梅 《数学物理学报(B辑英文版)》2004,(4)
The author considers the contact process on a branching plane Td×Z, which is the product of a regular tree Td and the line Z. It is shown that above the second critical point, the complete convergence theory holds. 相似文献
59.
介绍了轻中等质量核非对称裂变研究的新进展.通过对64,58Ni+12C和78,82,86Kr+12C反应复杂碎片的激发函数测量,发现流行的转动液滴模型和转动有限力程模型均不能复现实验的非对称裂变位垒数据.The excitation functions were measured for complex fragments with atomic number Z=4—25 emitted from the compound nuclei~(70,76)Se and~(90,94,98)Mo produced in the reactions~(64,58)Ni+~(12)C and~(78,82,86)Kr+~(12)C. The extracted mass asymmetric fission barriers have been compared with those calculated from macroscopic nuclear models. 相似文献
60.
Li Hong WANG Liang HUANG Institute of Material Medica Chinese Academy of Medical Sciences Peking Union Medical College Beijing 《中国化学快报》2006,(4)
Intramolecular cyclization of β -methyl substituted epoxide under aprotics (e.g. LDA in benzene) and protic conditions (e.g. LiOH in MeOH/H2O)both gave a mixture of β-, γ-, δ- and ε-lactam but in different ratio. 相似文献