动力学分光光度法测定痕量硫氰酸根的研究

利用SCN~-对溴酸钾氧化罗丹明B反应的抑制作用。建立了动力学光度法测定痕量SCN~-的新方法。检出限为0.30ng SCN~-/ml,测定范围为0.30～8.3ngSCN~-/ml.应用于吸烟者与不吸烟者尿中SCN~-的测定。结果较为满意。     

草酸锰分解过程的机理函数判别和动力学研究

用等温热重和线性升温热重分析法研究了草酸锰热分解过程,提出了判断其机理函数的3步判别法。经实验和理论分析证明,该反应受随机成核和晶核随后生长的过程(A_3a机理)支配,其活化能E=103.95 kJ/mol,频率因子A=4.448×10~8min~(-1).动力学补偿效应为IgA=0.09661E-1.2856     

聚丁二烯~(13)C-NMR谱图中一个新的共振吸收峰(T_4)

<正> 最近解析锂系和铁系含乙烯基聚丁二烯的~(13)C-NMR谱图,发现并确认了一个新的共振吸收峰。即聚丁二烯反式1,4-序列的第四峰,简称T_4峰。 Furukawa等对钼系和章哲彦等对铁系等二元聚顺-1,4-1,2-丁二烯的研究都指出在聚丁二烯的~(13)C-NMR谱图上,有四个谱峰属于顺1,4-序列。本文给出其化学位     

TFA-mediated intramolecular Friedel-Crafts reaction. An efficient metal and halogen free route to stereoselective synthesis of benzocycles

6-Acetoxy-4-alkenyl arenes undergo regio- and stereoselective intramolecular Friedel-Crafts reaction affording benzocycles in moderate to excellent yields in TFA/HOAc (3:1). It was observed that introduction of alkyls or phenyl group to the allylic acetate moiety facilitates the cyclization reaction. The optically active tricyclic (4bR,8aS)-4b,7,8,8a,9,10-hexahydrophenanthrene skeleton could also be easily obtained in excellent yields.     

一种计算稀土材料陷阱深度的新方法

表征陷阱材料的主要物理量是陷阱深度, 准确计算出陷阱深度对于研究陷阱材料具有重要的意义. 从能带模型出发, 利用速率方程分析了整个热释光过程, 提出了一种计算稀土材料陷阱深度的新方法, 替代以往利用单分子或双分子近似计算陷阱深度的方法. 以SrAl2O4：Eu^2＋, Dy^3＋及Sr4Al14O25：Eu^2＋, Dy^3＋材料为研究对象, 计算了陷阱深度. 研究表明, 这种计算方法能更准确、真实地描述其物理过程.     

Effects of sugar inhibition on cellulases and β-glucosidase during enzymatic hydrolysis of softwood substrates

A quantitative approach was taken to determine the inhibition effects of glucose and other sugar monomers during cellulase and β-Glucosidase hydrolysis of two types of cellulosic material: Avicel and acetic acid-pretreated softwood. The increased glucose content in the hydrolysate resulted in a dramatic increase in the degrees of inhibition on both β-Glucosidase and cellulase activities. Supplementation of mannose, xylose, and galactose during cellobiose hydrolysis did not show any inhibitory effects on β-Glucosidase activity. However, these sugars were shown to have significant inhibitory effects on cellulase activity during cellulose hydrolysis. Our study suggests that high-substrate consistency hydrolysis with supplementation of hemicellulose is likely to be a practical solution to minimizing end-product inhibition effects while producing hydrolysate with high glucose concentration.     

壳聚糖固体聚合物电池用膜

壳聚糖是甲壳素脱乙酰基的产物，具有良好的成膜性、生物相容性、环保以及价格低廉等特点。作为一种碱性高分子膜材料，近年来已成为聚电解质研究领域中的研究热点。本文综述了壳聚糖固体聚合物电池用膜的研究现状，其改性工艺主要包括共混、化学改性、质子酸掺杂、无机盐掺杂等方法，比较了各种工艺处理后壳聚糖固体聚合物电解质膜的性能差异，并就壳聚糖固体聚合物电解质膜中离子传导机理中有待解决的问题进行探讨，并提出了进一步改进壳聚糖固体聚合物电解质膜性能的研究思路。