硝酸酯分子几何构型的量子化学研究

运用MINDO / 3、MNDO 和AM1 三种半经验分子轨道(MO)方法, 通过SCF计算, 首次系统地获得了32个硝酸酯化合物分子的全优化几何构型。三种方法的计算结果与已报道的四个化合物(硝酸甲酯、吉纳、硝化甘油和太安)的实验结果相比, AM1法较好。所有硝酸酯的酯基(-ONO~2)具有近似不变的几何参数。直链烷基硝酸酯的键长和键角极为相近, 全部重原子均共平面。二元直链和四元硝酸酯具有对称的分子构型。     

碘酸钾存在下极谱催化波法测定陈皮甙

基于陈皮甙在ＫＩＯ３存在下产生的极谱催化波，拟定了测定陈皮甙的新方法。在 ０．５５ ｍｏｌ／Ｌ ＨＡｃ－０．０１ｍｏｌ／Ｌ　ＮａＡｃ（ｐＨ ４．００±０．０５）－１．０×１０～（－３）ｍｏｌ／Ｌ ＫＩＯ３缓冲溶液中，陈皮甙催化波的峰电位为－１．３５ Ｖ（ｖｓ，ＳＣＥ），它的一阶导数峰峰电流与陈皮甙浓度在２．６ × １０～（－７）～２．６ × １０～（－６）ｍｏｌ／Ｌ范围内呈线性关系（ｒ＝０．９９７０，ｎ＝６）。本方法比现有的电化学方法灵敏度高一个数量级。可用于直接测定中草药贯众水提液中陈皮甙含量。     

超临界流体色谱仪在天然产物研究中的应用

超临界流体可以用做色谱的流动相，使混合物质在色谱柱上得到分离，这种分离方法被称为超临界流体色谱(Supercdtical Fluid Chromatography,简称SFC)。作为色谱流动相的超临界流体，其作用与超临界流体萃取(Supercritical Fluid Extraction，简称SFE)类似。超临界流体对物质的溶解能力远比一般气体大的多，     

填充柱超临界流体色谱及其在石油产品上的应用

超临界流体可以用作色谱的流动相，使混合物质在色谱柱上得到分离，这种分离方法被称为超临界流体色谱(Supercntical Fluid Chromatography，简称SFC)。作为色谱流动相的超临界流体，其作用与超临界流体萃取(Supercritical Fluid Extraction，简称SFE)类似，超临界流体对物质的溶解能力远比一般气体大的多，其溶解能力可以相当于有机溶剂但是它比有机溶剂的扩散速度快、粘度低、表面张力小。     

Preferential Oxidation of CO in Excess Hydrogen over CuO-CeO2 Catalyst Prepared by Chelating Method

The CuO-CeO2 catalyst prepared by chelating method has a superior catalytic performance for the preferential oxidation of CO in rich hydrogen, compared with the CuO-CeO2 catalyst prepared by coprecipitation method. The CO conversions over these catalysts, at 120℃and 120000 ml/(g-h) in the absence of CO2 and H2O, are 99.6% and 88.6%, respectively, and the selectivity of O2 over these catalysts is very close (i.e. 51.3% and 55.8%, respectively). The influence of certain factors such as hydrogen concentration, carbon monoxide concentration, H2O, O2/CO ratios, and space velocity on the catalytic performance of CuO-CeO2 catalyst prepared by chelating method is also studied. The results show that the addition of hydrogen and H2O has a negative effect on the catalytic performance of CuO-CeO2 catalyst, however, the variation of space velocity and the O2/CO ratio causes a comparatively slight influence.     

Synthesis Hexadecyl 3-{4-[2-Hydroxy-3（isopropylamino）propoxy]phenyl}propionate as Potential Ligand for Liposome Targeting to Ischemic Myocardium

Novel hexadecyl 3- { 4-[2-hydroxy-3（isopropylamino）propoxy]phenyl }propionate （HPP）was synthesized and its effect on delivery of liposomes into cultured cardiomyocytes was examined. The structure of HPP was characterized by IH NMR, 1R and MS. The amount of cardiomyocytes uptake of HPP-liposome was 3.9-fold higher than plain-liposome, and the increase was 6.2-fold when hypoxia happens. It indicated that HPP was a potential ligand for liposome targeting to ischemic myocardium.     

大分子单体的制备方法

最常见的大分子单体是末端含碳—碳双键的烯类大分子单体，除此以外还有可开环聚合、可氧化偶联和可开环易位聚合的大分子单体等。本文介绍了大分子单体常用的制备方法。     

硅酸及其盐的研究 XX聚硅酸溶液中的酸强度与分子结构的关系

本文利用无机酸系列的酸强度(pKa值)与羟基上氧原子的亲电子超离域度S(E)成线性关系的规律性,找出聚硅酸系列的相应线性方程为:并由此推测低聚硅酸溶液中可能存在的硅酸结构:在三聚硅酸溶液中主要存在着六元平面环的三聚体;在四聚硅酸中则主要存在着三种环状的四聚体。     

Uniform Rice-like CdS Particles Prepared from Water-in-oil Microemulsions

IntroductionNano-sized semiconductors are of great interestdue to their special optical and electronic proper-ties[1,2].As one of the mostimportantⅡ—Ⅵsemicon-ductors,CdS has importantapplications in many fields,such as the solar cell field,non linear o…