Intramolecular crosslinking of poly(vinyl alcohol)

Poly(vinyl alcohol) is crosslinked in dilute solution (c=0.1 wt%) with glutaraldehyde. The reaction product is characterized by viscometry and gel permeation chromatography (g.p.c.). The intrinsic viscosity decreases with increasing degree of crosslinking and does not depend on temperature. G.p.c. reveals that the reaction product is not homogeneous, but consists of a mixture of particles with different sizes, possibly both intra- and intermolecularly crosslinked molecules. The intramolecularly crosslinked molecules are smaller in size than the initial polymer molecules and their size depends on the degree of crosslinking. They possess a narrow particle size distribution even if the initial polymer sample had a broad molecular weight distribution.     

合成直链烷基苯的锆磷铝固体酸催化剂 I.催化剂合成及其影响因素

合成了一系列用于苯与直链烯烃烷基化反应的含有杂原子的磷铝分子筛固体酸催化剂 (MeZrAPO 5 ) ,同晶取代磷铝分子筛骨架中磷和铝的杂原子包括锆和至少一种选自硅、硼、镓、锗、铁、镁、锡等的元素。考察了晶化温度、晶化时间、杂原子种类、铝源等因素对催化剂合成的影响 ,探索了合成样品中模板剂脱除的最佳条件。结果表明 ,晶化温度高于 15 0℃、n(TEA) /n(Al2 O3 )≥ 1 5以及加入Zr原子都有利于直接生成MeZrAPO 5晶相 ;用小晶粒和高结晶度的铝源合成时 ,分子筛的结晶度高。     

奎宁印迹聚合物的吸附与识别特性的研究

以奎宁为模板分子 ,利用分子印迹技术合成了一种新型的类似于人工受体的印迹聚合物 ,研究了它对奎宁和其它底物的吸附特性和选择性识别能力 ,并对其固相萃取性能做了初步的研究。     

Cholesterol‐imprinted polymer receptor prepared by a hybrid imprinting method

A novel cholesterol‐imprinted polymer (CMIP‐H) was prepared by a hybrid method of covalent imprinting and non‐covalent imprinting. This approach involves the copolymerization of a template‐containing monomer, cholesteryl 2‐hydroxyethyl methacrylate carbonate, and a cross‐linker, followed by hydrolysis to afford a flexible guest‐binding site accompanied with the easy and efficient removal of a ‘sacrificial spacer’. The effect of solvent on the binding capacity of CMIP‐H towards cholesterol was studied, indicating that a good binding capacity towards cholesterol could be achieved in a less‐polar solvent. The binding experiments of CMIP‐H towards a series of structural analogues of cholesterol, including cholesterol acetate, progesterone and stigmasterol, were carried out in hexane. The results showed that CMIP‐H almost did not bind cholesterol acetate at all because the hydrogen‐bonding site is blocked. It exhibited a similar binding towards both cholesterol and stigmasterol, but much higher binding towards progesterone. Copyright © 2005 Society of Chemical Industry     

掺杂Yb的TiO2光催化剂的制备和性能

采用溶胶-凝胶法制备了Yb掺杂TiO2纳米光催化剂,并通过XRD和BET等手段进行了表征.以对苯二甲酸作为探针分子,结合化学荧光技术研究了光催化剂表面羟基自由基的生成;并以苯酚为光催化降解反应模型化合物,考察了光催化剂的活性.测定了苯酚在TiO2和Yb掺杂TiO2光催化剂上的吸附常数.结果表明：Yb掺杂使TiO2的粒径减小,比表面积增大,同时导致羟基自由基的生成速率增大.Yb掺杂有利于反应底物在催化剂表面的吸附,Yb的最佳掺入量为Yb/Ti摩尔比=0.8%.     

Study of impurity induced modifications in amorphous N-type (GeSe3·5)100−x Bi x using high pressure technique

The technique of high pressure is utilized to study the carrier transport behaviour in doped and undoped bulk amorphous (GeSe_3·5)_100−x Bi _x (x=0, 2, 4, 10) down to liquid nitrogen temperature to observe impurity induced modifications in amorphous semiconductors. It is observed that pressure induced effects in lightly doped (2 at % Bi) and heavily doped (x=4, 10) semiconductors are markedly different. Results are discussed in view of the incorporation behaviour of the bismuth impurity.     

掺杂VO2的特性、制备方法及应用

VO2在68℃时发生从低温的单斜相向高温四方相转变，同时伴随着光、电、磁性能的突变。通过掺入其它杂质元素，能有效改变其相变温度和光、电性能，这些优异特性使其具有更好的应用前案。本文综述了掺杂的原理，掺杂对VO2相变影响、常用的掺杂方法及目前的应用情况，这对其进一步的研发应用具有重要的意义。     

Retaining maximum antioxidative potency of wheat germ oil refined by molecular distillation

A process of physical refining wheat germ oil using the technique of molecular distillation (MD) is presented in this work. Wheat germ oil was obtained from the germ by solvent extraction using hexane and also by cold pressing. The oil extracted with hexane was degummed and bleached before deacidification in order to modify the parameters of phosphorus and color. The goal in carrying out the stage of physical refining by MD was to preserve the maximum amount of original antioxidative potential obtained from extraction of the crude oil. The effect of evaporation temperature of one‐stage MD on the efficiency of free fatty acid elimination was studied. The antioxidant portion was followed by means of analytic determination of tocopherols by high‐performance liquid chromatography. Tocopherol retention up to 98% was achieved in the oil extracted by pressing, and yields of up to 96% were achieved in the oil extracted with hexane. Copyright © 2007 Society of Chemical Industry     

择形催化合成2,6-DMN的研究进展

介绍了2,6-二甲基萘(2,6-DMN)的制备方法,详细论述了萘、甲基萘在分子筛催化剂上择形催化合成2,6-DMN的研究进展,提出了择形催化合成2,6-DMN的研究方向。     

影响道路沥青低温抗裂性能的因素

用弯曲梁流变仪、直接拉伸试验机对7种国内外油源沥青样品进行了低温抗裂性能的评价，从沥青的四组分、相对分子质量及其分布来分析其对沥青低温抗裂性能的影响，结果表明，沥青的相对分子质量分布宽，对沥青的低温抗裂性能有利。