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排序方式: 共有638条查询结果,搜索用时 15 毫秒
191.
ZHONG Gui yun LIU Hua XIE Qing lan * Institute of Elemento organic Chemistry Nankai University Tianjin P. R. China 《高等学校化学研究》2002,18(3):277-279
IntroductionThe drug- molecules are called as silyl- drug ifasilicon atom replaced one carbon atom of theorganic- drugs.Generally,they have low toxicityand pro- long efficiency.Many methods have beendesigned in order to decrease the toxicity oforganotin compounds and organosilicon which hasbeen proved to be effective.Torque[1] is a newacaricide made by America Shell Company,itsmolecular formula is [( Ph Me2 Si CH2 ) 3 Sn]2 O.Tacker[2 ] synthesized the compounds( Ph Me2 Si CH2 ) 3 Sn X[… 相似文献
192.
WANG Bai Jing WEI Min ZHANG Li Ping * School of Life Science Northeast Normal University Changchun P.R. China 《高等学校化学研究》2003,19(1):37-40
IntroductionBoth Cordycepsmilitarvs( L.) Link and Cordy-ceps sinensis Sacc belong to the claviceps purpureafamily cordyceps genus,and Cordyceps sinensisSacc has received much attention because of its spe-cial function.But the scarcity of it in quantity andthe difficulty of it to be cultivated have made theapplication of this kind oforganism limited.Cordy-ceps militarvs( L .) Link is relatively easier to becultivated. What is more,the determination ofpharmaceutical chemistry and pharmacolog… 相似文献
193.
Wei Jiang HE Fang LIU Zhi Feng YE Zi Jian GUO Jun Bai LI Long Gen ZHU* State Key Laboratory of Coordination Chemistry Nanjing University Nanjing Laboratory of Colloid Interface Science Center for Molecular Science Institute of 《中国化学快报》2000,11(11)
Since calixarenes and their derivatives have unique coordination abilities to metal ions and inclusion abilities toward neutral organic molecules, they have been widely studied in the field of molecular recognition, transportation and separation1. In order to explore these functions, membranes such as monolayers and Langmuir-Blodgett (LB) films formed by calixarenes, are often used for these purposes2-6. However, a crucial factor that hinders their application is the weak mechanical strength … 相似文献
194.
Ng Seik Weng~* 《结构化学》2000,(6)
1 INTRODUCTIONSeveralincorrectspacegroupshavebeenre assignedbymakinguseofsimulatedstructurefactors;however,thecruxofthisoranyspacegrouprevisionistheaccuratereportingofthespacegroupandatomiccoordinatesoftheincorrectlydeterminedstructuresincethetruestruc… 相似文献
195.
1 INTRODUCTIONAbscisicacid(ABA)isoneofplanthormoneswhichwasisolatedfromyoungcottonfruitsin1963[1].Itnotonlyinhibitsplantgrowth,butalsoprotectsplantsa-gainstdeprivationofwaterduringdroughtdays[2].Hydroxyalkylphosphonicacidsandtheirderivativesappeartobeveryimportantfortheirwidebiologicalactivitiesintheinhibitionofenzymes,fungicidesandplantgrowthregulation[3].Wedesignedandsynthesizedthetitlecompound4,theunsaturatedphosphonateanaloguesofABA,whichexhibitsplantinhibitoryactivityontheelongati… 相似文献
196.
在科技文献中,地震常被比喻为非线性动力学过程或统计物理中的相变过程.文章探讨了如何从非线性力学中的分岔理论以及统计物理内的朗道相变理论出发,从势磊穿越,临界涨落与临界慢化等多个角度来分析和了解地震发生的全过程.文章作者试图在这些非线性力学与统计物理的基础上,综合地震过程中在时间与空间上应出现的前兆,解释如何可能做出具有普适性的数值地震预测. 相似文献
197.
Ultrafast internal conversion dynamics of 2-chloropyridine were studied by femtosecond time-resolved photoelectron imaging spectroscopy coupled with time-resolved mass spectroscopy. The ultrafast internal conversion from the second excited state (S2) to the first excited state (S1) via an adjacent conical intersection within (162±5) fs was clearly observed from the time-dependence of the photoelectron spectra. The subsequent deactivations involved the coupling of S2/S0(the ground state) and S1/S0 conical intersections, which occurred on a timescale of about (5.5±0.3) ps, and led to the internal conversion to the ground state from the S2 and S1 states. 相似文献
198.
SONG RuiBo DAI FuPing & WEI BingBo* Department of Applied Physics Northwestern Polytechnical University Xi’an China 《中国科学:物理学 力学 天文学(英文版)》2011,54(5):901
Rapid solidification of binary Cu-22%Sn peritectic alloys and Cu-5%Sn-5%Ni-5%Ag quaternary alloys was accomplished by glass fluxing, drop tube and melt spinning methods. The undercooled, by glass fluxing method, Cu-22%Sn peritectic alloy was composed of α(Cu) and δ(Cu41Sn11) phases. If rapidly solidified in a drop tube, the alloy phase constitution changed from α(Cu) and δ(Cu41Sn11) phases into a single supersaturated (Cu) phase with the reducing of droplet diameter, and the maximum solubility of Sn in (Cu)... 相似文献
199.
200.