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131.
132.
Seven polystyrene-type adsorbents (Ⅰ—Ⅶ) were synthesized by the modification of styrene-divinylbenzene copolymer respectively with hydroxymethyl, aminomethyl, methoxymethyl, phenoxymethyl, (4-hydroxy phenoxy)methyl, (4-acetylphenoxy)methyl, and acetyl groups. Their structures were characterized with chemical methods and physical techniques. The adsorption capacities of the adsorbents to stevioside and gypenosides were determined via batch test in which the HPLC method was used for the analysis of Saponin concentration of solution. The results showed that all the adsorbents could adsorb these saponins to a certain extent, but Ⅵ and Ⅶ had large capacities owing to their moderate polarities. 相似文献
133.
Qi SUN Qiang XIAO Yong JU* Yu Fen ZHAO The Key Laboratory of Bioorganic Phosphorus Chemistry of Education Ministry Department of Chemistry School of Life Sciences Engineering Tsinghua University Beijing 《中国化学快报》2003,14(7):685-688
It is known that saccharides linked to proteins via a phosphoester hinge can function as immunological determinants. Under regular physiological conditions, it has been suggested that the role of phosphonate group is to direct the protease towards basic substrates1. Phosphoramidon a, which was isolated from a culture filtrate, is a potent inhibitor of the thermolysin, a metallo-endopeptidase. It is a glycosylated dipeptide, which has a L-rhamnose attached to the N-terminal of Leu-Trp dipep… 相似文献
134.
You Liang ZHAO Chuan Fu CHEN Fu XI* State Key Laboratory of Polymer Physics Chemistry Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 《中国化学快报》2002,13(5):420-421
Much effort has been dedicated to the molecular design and synthesis of model proteins to define protein folding interactions and to develop protein-based materials. Among them, the ring-opening polymerization of -amino acid-N-carboxyanhy- drides (NCAs) has drawn much attention because the resulting artificial polypeptides have wide applications in biotechnology, biomineralization and diagnostics1, 2. It is well known that dendrimers are hyperbranched macromolecules possessing a very high co… 相似文献
135.
The present paper covers the reaction ergodography for the addition of AlH3 to acetylene investigated by ab initio calculation with RHF/3-21G basis set. The changes in some physical properties along the reaction path (IRC) are presented. The formations of FMOs of the transition state have been analyzed according to the Fukui' s method. On the basis of the perturbation theory and Wolfsborg Helmholtz formula, we calculated the FMO' s energy orders of TS and its formation that shows the HOMO of TS consists of LUMO, HOMO of AlH3 and HOMO of HCCH. 相似文献
136.
通过苯基甲基二乙氧基硅烷和苄基甲基二乙氧基硅烷的缩合反应制备了聚苯基甲基和聚苄基甲基硅氧烷。研究了它们与含氟酰基过氧化物间的反应。经酸碱滴定及IR、^1H NMR和^19F NMR光谱分析确证反应主要生成苯环上氟烷基取代产物。通过测定经氟烷基化后聚硅氧烷处理的玻璃表面的接触角,初步评价了氟烷基化率对其表现性能变化的影响。 相似文献
137.
用高效液相色谱法(HPLC)在正相条件下,用自制的涂敷直链淀粉-三(3,5-基苯基氨基甲酸酯)(ADMPC)手性固定相直接拆分了高效低毒的抗心绞痛药物雷喏嗪外消旋体(Ranolazine),并考察了二元及三元流动相体系对样品分离的影响,结果表明,三元流动相中的拆分结果远远好于二元流动相,流动相中不同种类醇改性剂及含量对样品保留时间和立体选择性有不同程度的影响. 相似文献
138.
Jin Ling CHAI Yan Hong GAO Kong Shuang ZHAO Gan Zuo LI Gao Yong ZHANG 《中国化学快报》2005,16(9):1263-1266
The dielectric relaxation spectroscopy (DRS) of Winsor I -Ⅲ microemulsions for nonionic surfactant octyl polyglucoside CsG1.46/1-butanol/cyclohexanedwater system was studied. The experiment shows that the permittivity decreases with the increase in the frequency and clear dielectric relaxation phenomena were observed. Permittivity obviously decreases with the change of the microstructure of the microemulsion, W/O, B.C. and O/W can be distinguished by the permittivity. 相似文献
139.
ZhiQuanZHAO LiZengPENG YuLinLI 《中国化学快报》2005,16(3):290-292
The phenomenon of migration of the silyl groups from α-oxygen to β-oxygen in sodium aldol reaction was observed for the first time in this paper. 相似文献
140.
利用电动势法得到了牛血清白蛋白(BSA)与十二烷基硫酸钠(SDS)相互作用的结合等温线. 通过四阶导数紫外光谱法和荧光光谱法研究了相互作用过程中芳香族氨基酸残基微环境极性的变化. 通过研究发现, 随着SDS浓度的逐渐增大, SDS在BSA上的平均结合数(v)逐渐增大, 色氨酸(Trp)残基所处微环境的极性在减弱后保持基本不变, 酪氨酸残基所处微环境的极性在明显增强后稍有减弱, 苯丙氨酸残基所处微环境的极性略有增强. 结果表明, 当v由0增大到14时, SDS主要结合在BSA的Trp-213附近并逐渐形成聚集体, 从而诱导BSA由结构域ⅡA 开始逐渐展开. 此后, SDS呈正协同作用的特点与BSA 结合, v急剧增大. 当v约为302 时, SDS在BSA上的结合基本达到饱和, BSA的构象趋于稳定. 相似文献