Microstructure and Ion Exchange in Stearic Acid Langmuir-Blodgett Films Studied by Fourier Transform Infrared-Attenuated Total Reflection Spectroscopy

Fourier transform infrared-attenuated total reflection (FTIR-ATR) spectra have been recorded of 11-layer Langmuir-Blodgett (LB) films of stearic acid deposited at various surface pressures (0.1, 15, and 35 mN/m), and the molecular orientation angles were evaluated quantitatively, which supplied insight into the molecular order with the alkyl chains tightly packed like crystal in the LB films deposited at the zero and higher surface pressures. These experimental results indicate that, in the Langmuir film as the precursor of LB films, stearic acid molecules self-aggregate to form two-dimensional crystalline domains already even at the zero surface pressure, which results in the inhomogeneity of monolayer. The analysis of dependence of nu(C=O) intensity on the surface pressure, surface density, and subphase temperature leads to the conclusion that the defects in LB films originate from the Langmuir film and be conserved upon deposition. Annealing below 50 degrees C and cooling could improve the monolayer homogeneity, and thus a defect-free or low-defect LB films can be deposited. Furthermore, ion exchange conducted in the LB films, on the other hand, confirms the existence of structure defects in LB films of stearic acid. The polar plane microstructure, lateral transport along the polar planes and the coordination types of stearic acid/cation system may be the rate-limiting process. The results have implication on the possible uses of stearic acid LB films as ion-exchange materials or sensors. Copyright 2001 Academic Press.     

正丁基锂四氢呋喃引发α-甲基苯乙烯阴离子平衡聚合动力学及反应机理研究

本文研究了以正丁基锂为引发剂,四氢呋喃为添加剂,环己烷为溶剂中的α-甲基苯乙烯阴离子平衡聚合动力学。讨论了体系中的反应活性种;提出了聚合机理;得到了聚合温度为20℃时的平衡单体浓度与活性种速率常数及添加剂浓度之间的关系式。     

白血病骨髓移植病人全血微量元素铜的变化及其意义

为了研究白血病骨髓移植病人全血微量元素铜的变化及其意义 ,用原子吸收光谱法检测了正常对照组与白血病骨髓移植患者预处理前及移植后骨髓空虚期全血微量元素铜的含量。结果表明 ,正常对照组全血铜浓度与白血病骨髓移植患者预处理前全血铜浓度差异无显著性 (P >0 0 5 ) ,而与骨髓空虚期全血铜浓度有显著性差异 (P <0 0 5 ) ,说明白血病缓解后血铜接近正常对照组水平 ,而白血病骨髓移植患者预处理后骨髓空虚期全血铜含量高于正常对照组 ,说明预处理影响微量元素铜的代谢 ,本文就其影响机理进行了研究     

The Study of Anti-tumor Activity of Trichosanthin by Cyclic Voltammogram

IthasbeenreportedthatTrichosanthi11(TCS),isolatedfromrkiI-ilolt)ii,hasanti-tumorI-4andanti-vira1activities5-'.Someanti-tun1orremedies,whicharedesignedfromTCS,arebeingtestedanddeveloped'-.'.StudyingthebioIogicalphenomenonbyelectrochemicalmethodsisanewhotresearchspotemerginginrecentyears".Manyresultsshowedthatnotonlytheenzymesystemsuchassuccinatedehydrogenasedisplayedthediode-likebehaviorduringtheelectrontransferprocess",butalsothehigh1yorganizedorganeIle,forexample,mitochondria,andevenintac…     

苏丹Ⅰ与牛血清白蛋白的相互作用特征

利用荧光技术研究了在人体生理酸度条件下,苏丹Ⅰ与牛血清白蛋白相互作用,发现苏丹Ⅰ对牛血清白蛋白有较强的荧光猝灭作用,用Stern-Volmer和Line Weaver-Burk方程处理荧光猝灭数据,得到了反应的结合常数、结合热力学性质和结合位点等参数。根据热力学常数确定了该药物与血清白蛋白之间的作用力类型,在此基础上依据F rster非辐射能量转移机理探讨了苏丹Ⅰ与BSA相互结合时其供体-受体间的距离。     

LaPO4纳米微粒的制备及表征

Surface-modified LaPO4 nanoparticales were synthesized in the mixture solvent of water-ethanol with the surface modification age of dialkylphosphate. The conditions of synthesis and characterization were discussed. The results indicated that nanoparticle core of LaPO4 and surface-modified layer were formed. The surface-modified nanoparticles of LaPO4 can be dispersed in organic solvent and has better lubricating properties.     

液相色谱专家系统中柱系统推荐规则的建立和验证

把分子结构和分子、离子静电作用力作为影响溶质保留值和选择性的基本点,提出了液相色谱专家系统柱系统推荐的基本规则,由此可以从溶质所包含的基团或官能团的信息进行色谱柱系统推荐。为了验证这些规则的正确性,应用几类常用的或典型的样品从分子结构通道进行液相色谱柱系统推荐,获得满意的结果。     

Synthesis and Photophysical Properties of Hetero‐Bischelated Complexes of Rhodium(III) Containing Phenyl‐Pyridin‐2‐Ylmethylene‐Amine

Three new hetero‐bischelated rhodium (III) complexes of cis‐[Rh(PA)(L)Cl₂]Cl (where PA = phenylpyridin‐2‐ylmethylene‐amine; L = 2,2′‐bipyridine, 2,2′‐dipyridylamine and 1,10‐phenanthroline) have been successfully prepared and characterized. Each complex shows high intensity bands in the UV region, and these are assigned to spin‐allowed π‐π* transitions. The medium‐intensity absorption band profile in the lower energy region can be explained by convolution of spin‐allowed CT and d‐d* transitions. The emission spectra at low temperature (77 K) of these complexes in EtOH/MeOH (4:1 v/v) are virtually identical. They all exhibit a broad, symmetric, and structureless red emission with a microsecond lifetime and hence are assigned as the d‐d* phosphorescence.     

Quality evaluation of fingerprints of herbal medicine with chromatographic data

In this study, local least squares (LLS) and principal component analysis (PCA) were applied to deal with the disturbances in a data set of chromatographic fingerprints after necessary data transformations. It has been demonstrated that PCA with standard normal variate (SNV) transformation of data led to meaningful classification of 33 different Erigeron breviscapus herbal samples. The result was also corroborated by variance squares discriminant method. The quality of herbal objects was further evaluated, and the causes of this fact have been explained from a chemical point of view. At the same time, it implied an idea for qualitative evaluation of the herbal objects with a common class pattern of chromatographic fingerprints.