铁系催化剂组分间的作用

在 2 5℃加氢汽油介质中 Fe Cl3- Al(i- Bu) 3- phen体系为胶体催化剂的基础上 ,用电导率结合UV- Vis光谱对铁系催化剂各组分之间的相互作用作进一步的分析 .实验结果表明 :催化剂组分以离子对的形式参与反应 ;Al(i- Bu) 3以缔合状态存在并解离成离子对 ,它与 Fe Cl3作用是形成胶粒的主要反应 ;Fe2 +位于催化剂胶粒表面 ,Phen与 Fe2 +络合有阻止 Fe2 +被还原成更低价态 (Fe+、Fe0 )的作用 ;适当过量的 Al(i- Bu) 3形成双电层 ,使催化剂胶粒稳定 ,同时将 Fe3+还原成 Fe2 +.     

实现计算机管理的高校读者工作

由于计算机在高校图书馆的普及 ,为师生的文献检索带来了极大的便利 ,也为图书馆的发展提供了良好机遇。图书馆只有为读者提供优良舒适、高技术的借阅环境 ,丰富的文献特藏及技术过硬的专业队伍 ,才能保证信息服务质量     

β-环糊精玫瑰香精微胶囊的制备

用β 环糊精作为壁材,探讨了玫瑰香精环糊精微胶囊的制备工艺。采用正交试验获得了微胶囊的最佳包结条件,皮芯比为10∶3,包结温度为50℃,w(β CD)为15%,pH值为7。利用SDT 2960热分析仪对样品进行热重分析,测试包埋率,通过对比玫瑰香精、β 环糊精、微胶囊样品的红外光谱图,表征包结情况。     

丙烯酰胺-苯乙烯双亲嵌段共聚物的微结构及水溶液行为

通过改变丙烯酰胺(AM)与苯乙烯(St)的投料比、苯乙烯与表面活性剂的加入量之比及引发剂加入量,在微乳液中制备了分子链微结构系列变化的丙烯酰胺-苯乙烯双亲嵌段共聚物(PAM-b-PSt),用荧光探针法与表面活性测定法详细地研究了共聚物中PSt嵌段长度、含量及分子量等微结构因素对共聚物在水溶液中的疏水缔合性与表面活性的影响.结果表明,当共聚物水溶液的浓度高于临界缔合浓度时,PAM-b-PSt的疏水缔合作用以分子间的缔合为主.若共聚物中PSt嵌段含量及分子链长一定时,随着PSt疏水嵌段长度增长,PAM-b-PSt的疏水缔合性增强,而对共聚物的表面活性影响很小.若共聚物中PSt疏水嵌段长度及分子链长一定时,PAM-b-PSt的疏水缔合性随着PSt嵌段含量的变化而变化,当PSt嵌段含量一定时,使大分子链之间产生最强的疏水缔合作用;而其表面活性则随着PSt嵌段含量的增大而增强.若共聚物中PSt疏水嵌段长度及含量一定时,分子量对其表面活性有较大的影响,分子量越高,表面活性越差;同时,在较稀的溶液浓度范围内,分子量对PAM-b-PSt的疏水缔合性的影响则很小.     

Effect of Excipients on Stability and Structure of rhCuZn-SOD Encapsulated in PLGA Microspheres

When a protein is encapsulated into poly (DL-lactide-co-glycolide)(PLGA) microspheres by means of thedouble-emulsion method, the harsh microspheres formation process including ultrasonifieation, exposure toan organic solvent and a polymer may cause the denaturation of the protein. In this study, we investigatedthe enzymatic activity change and the effect of the excipients on the stability of recombinant human Cu ,Zn-su-peroxide dismutase (rhCu, Zn-SOD) during the emulsification. The specific activity recovery was found to beconcentration dependent and the excipients involved such as PEG 600 and Tween 20. and trehalose wereshown to increase the stability of rhCu, Zn-SOD. The protein structural integrity within the microsphereswas analyzed by FTIR. The structure of rhCu, Zn-SOD within PLGA microspheres containing trehalose wasfound to be similar to that of the native solid state, whereas the protein encapsulated during the preparationin the absence of any excipient changed due to the possible hydrophobic interaction with the polymer. The re-sults suggest that a rational stability strategy for protein to be encapsulated into microspheres should aim atdifferent processes.     

水热法α-Al2O3自发结晶和形态控制

本文研究了高温高压水热法合成α-Al2O3晶体的形态特征.在水热条件下,α-Al2O3的晶体形态和合成温度、矿化剂浓度有密切关系.当KOH浓度和温度较低时(如0.1M KOH,390℃),显露c{0001}、a{11-20}、r{01-12}、n{11-23}晶面.随着矿化剂浓度和温度的提高,晶体r{01-12}和n}11-23}面的显露面积越来越小,直到完全消失(如2MKOH,400℃),晶体只显露底面c{0001}、和柱面a{11-20},呈六棱柱形.     

构象分析初期的研究和有关的思考

简单介绍构象分析方法创建初期的研究工作,构象分析方法的2位创始人OddHassel和Derek H.R.Barton的简单情况,并分析由此给我们的启示。     

Stability of Crystal Growth Face and Dissolution Face in Crystallization from Solution under Microgravity

The stability of the shapes of crystal growth face and dissolution face in a two-dimensional mathematical model of crystal growth from solution under microgravity is studied.It is proved that the stable shapes of crystal growth face and dissolution face do exist,which are suitably shaped curves with their upper parts inclined backward properly.The stable shapes of crystal growth faces and dissolution faces are calculated for various values of parameters,Ra,Pr and Sc.It is shown that the stronger the convection relative to the diffusion in solution is,the more backward the upper parts of the stable crystal growth face and dissolution face are inclined.The orientation and the shape of dissolution face hardly affect the stable shape of crystal growth face and vice versa.     

Nd∶NaY(WO4)2激光晶体生长

采用提拉法生长出了四方晶系白钨矿结构的Nd:NaY(WO4)2(简称Nd∶NYW)激光晶体,尺寸为20mm×30mm.通过TG-DTA差热分析得到晶体的熔点为1211℃,从XRD分析得到晶胞参数为a=b=0.5212nm ,c=1.1268nm ,晶胞体积V=0.3062nm3.讨论了Nd∶NYW晶体的生长工艺,给出了晶体生长的最佳工艺参数.通过比较Nd∶NaBi(WO4)2(简称Nd∶NBW)和Nd:NYW的XRD、红外光谱和拉曼光谱测试结果,认为二者结构基本相同,为四方晶系白钨矿结构、I(4)空间群.     

脉冲微分方程非线性边值问题

本文用上,下解方法,根据Leray-Schauder不动点定理给出一类带有非线性边界条件的脉冲微分方程边值问题解的存在性定理。