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51.
Dong Yu ZHAO Sheng Hua YANG Ming HU Xue Yi MA* Department of Chemistry National Laboratory of Applied Organic Chemistry Lanzhou University Lanzhou 《中国化学快报》2003,14(2)
Andrographolide (Andro) (Figure 1) is a diterpene lactone isolated from Andrographis paniculate Nees1. It has showed several biological activities including analgesic, antipyretic and anti-inflammatory effects2. However, its poor water solubility and unstability towards oxygen restrained its application. In pharmaceutics, b-CD is used to increase solubility and stability3. We have prepared the inclusion compound of Andro/b-CD (Figure 2) under microwave irradiation4. It has been found… 相似文献
52.
YANG Hong-li * VAULTIER MichelSynthèse et Electrosynthèse Organiques UMR CNRS Université de Rennes Campus de Beaulieu Avenue du Général Leclerc RENNES CEDEX France 《高等学校化学研究》2002,18(4):414-418
IntroductionGrubbs catalyst bis(tricyclohexylphosphine)benzylidene ruthenium( ) dichloride1 can be usedin a variety of ring- closing metathesis (RCM )reactions,cross metathesis(CM) reactions andring- opening metathesis polymerization(ROMP) [1— 4 ] .It remains metathetically active inthe presence of a variety of functional groups,suchas carbonyls,alcohols,and amides[1] .The use ofcatalyst1 in the synthesis has drawn more andmore attention[5— 13] . However,this catalyst is veryexpensive,an… 相似文献
53.
本文采用分数维方法, 在讨论Al0.3Ga0.7As衬底上GaAs薄膜的分数维基础上, 计算了GaAs薄膜中的极化子结合能和有效质量. 随着薄膜厚度的增加, 极化子结合能和质量变化单调地减小. 当薄膜厚度Lw<70 Å并且衬底厚度Lb<200 Å时, 衬底厚度的变化对薄膜中极化子的结合能和质量变化的影响比较显著, 随着衬底厚度的增加, 薄膜中极化子的结合能和质量变化逐渐变大; 当薄膜厚度Lw>70 Å或者衬底厚度Lb>200 Å时, 衬底厚度的变化对薄膜中极化子的结合能和质量变化的影响不显著. 研究结果为GaAs薄膜电子和光电子器件的研究和应用提供参考.
关键词:
分数维方法
GaAs薄膜
极化子
低维异质结构 相似文献
54.
LIU KaiQiang PENG JunXia XUE Min YAN Ni LIU Jing & FANG Yu* Key Laboratory of Applied Surface Colloid Chemistry Ministry of Education School of Chemistry Materials Science Shaanxi Normal University Xi’an China 《中国科学B辑(英文版)》2011,(3)
Five new diacid amides of di-cholesteryl L-glycinates were designed and prepared.The compounds with linkers containing 0,1, 2,3,or 4 methylene units are denoted as 1,2,3,4,and 5,respectively.Their gelation behaviors in 25 solvents were tested as novel low-molecular-mass organic gelators(LMOGs).It was shown that the length of the linker connecting the two-cholesteryl residues in a gelator plays a crucial role in the gelation behavior of the compound.1 gels 11 of the 25 solvents tested at a concentration lowe... 相似文献
55.
DING Jian DING Xue-jia XU Ri-wei YU Ding-sheng * Materials College Beijing University of Chemical Technology Beijing P. R. China Received May 《高等学校化学研究》2005,21(2):227-231
The viscoelastic behavior of isotactic polypropylene with ultra-high molecular weight (UHPPH) and broad molecular weight distribution(MWD), produced in the presence of Ziegler-Natta catalyst, was investigated by means of oscillatory rheometry at 180 and 200 ℃, whose loss modulus(G") plots at 180 and 200 ℃versus the natural logarithm of angular frequency(ω) present a pronounced maximum at 34.35 and 69.21 rad/s, respectively, and do not show a maximum peak at 0. 01-100 rad/s for Ziegler-Natta catalyzing ethylenepropylene random copolymerization (PPR) with a conventional molecular weight and broad MWD. The fact indicates that the high molecular weight is responsible for a maximum peak of G"(ω) vs. lnω curves for UHPPH. This makes it possible to determine the plateau modulus (G0N) of UHPPH from a certain experimental temperature G"(ω) curve directly. For UHPPH, the G0N determined to be 4. 28×105 and 3. 62×105 Pa at 180and 200 ℃, respectively, decreases with the increase of temperature and is independent of the molecular weight, which directly confirms reputation theoretical prediction that the G0N has no relation to the molecular weight. 相似文献
56.
Ling Tian TANG Yi WANG Xin Qi LIU Shao Wen HU Tai Wei CHU Xiang Yun WANG* College of Chemistry Molecular Engineering Peking University Beijing 《中国化学快报》2005,16(3):345-348
Benzimidazole compounds have attracted a renewed interest recently owing to theirpotential applications in high-performance composite materials, electronic chemicals,photosensitive materials, and their special potentials in biological and/or medicinalapplication1,2. Typically, aromatic compounds with near planar structures and contain-ing hydrogen-donor groups or groups, which are capable of being protonated, havespecial interactions with DNA via intercalation, hydrogen-bonding, and so on3.Me… 相似文献
57.
1INTRODUCTIONBenzodiazepinecompoundsareimportantpharmaceuticalagents〔1,2〕.Recentlyithasbeenfoundthatbenzodiazepinetricyclicde... 相似文献
58.
XI Shang-Zhong 《结构化学》2001,20(4)
1 INTRODUCTIONAtrope alkaloids, which exist in eggplant plants, such as atrope and scopolamine, are used as a series of important drugs in medical science [1,2]. The typical character of atrope alkaloid is that these compounds contain the main skeleton of 8-azabicycle[3,2,1]octane , which results in the very complicated synthetic routine[3]. During our research for the reaction of 1,3,5,7-tetraphenyl-4- nitro-1,7-heptadione with low-valent titanium reagent, we easily synthesized the title … 相似文献
59.
Xue Mei LUO Wei Jiang HE Yu ZHANG Zi Jian GUO Long Gen ZHU* State Key Laboratory of Coordination Chemistry Nanjing University Nanjing 《中国化学快报》2000,11(11)
Selectively chemical cleavage of peptides and proteins is one of the most important reactions in both chemical and biochemical processes. Over the past decade, the interaction of palladium(II) complexes with methionine, cysteine and histidine-containing peptides and proteins and the hydrolytic cleavage of the corresponding amide bond by Pd(II) complexes have been extensively studied1-13. However, reports concerning the directly selective hydrolysis of peptides and proteins with other simple … 相似文献
60.
Zhi NA Bei JIANG Hui YANG Zhong Wen LIN Han Dong SUN* Laboratory of Phytochemistry Kunming Institute of Botany Chinese Academy of Sciences Kunming Chemistry Deparment of the College of Life Science Chemistry Yunnan University K 《中国化学快报》2001,(8)
Isodon enanderianus (Hand. -Mazz.) H. W. Li, has been used in folk medicine as anti-inflammatory and detoxified agent1. The Isodon genus is known to be rich in ent-kaurane diterpenoids, a series of new ent-kaurane diterpenoids have been isolated from the dried leaves of I. enanderianus2-4. In order to find more biologically active substances, we have carefully investigated the chemical constituents of I. enanderianus collected in Shiping county of Yunnan province, and as a result, enanderi… 相似文献