Sol-Gel法制备氧化铝负载铜基超细粒子影响因素的研究

通过对Sol-Gel法制备氧化铝负载铜基超细粒子的研究,表明PEG分散剂对粒度分布有重要影响;采用XRD对制得的催化剂表面组成进行了研究,指出了发生固相反应生成活性较低的CuAl2O4的影响因素。     

基于AFS600的CAN核重用设计

通过分析CAN核管脚信号的有效电平和添加RAM块,实现了CAN核的移植;通过改双向总线为单向总线和设计时序转换桥,实现了Core8051和修改后的CAN核的通信。经试验验证,CAN核和Core8051核组成的CAN节点,可以与CAN总线上的测试设备正常通信。     

PEG/壳聚糖相变材料储热性能研究

用物理共混法将PEG和壳聚糖共混物改性,得到具有固-固相变性能的储能材料,用DSC具体研究了PEG的质量分数及PEG的相对分子质量对共混材料的相变温度和相变焓的影响。结果表明,不同相对分子质量的PEG在63～68℃之间具有较大的相变焓,且相变焓在180～220J/g之间,均可做为相变储能材料;相对分子质量为8000的PEG相对于其他的PEG更适宜做相变储能材料,共混物中PEG的质量分数低于85%时才表现为固-固相变材料。     

亚临界锅炉汽包水位计偏差大探析

基于汽包水位测量原理进行误差分析,比对现有汽包炉水位计特性,进行有针对性的调整和改造,在很大程度上可以减少汽包水位计的偏差,提高汽包水位测量的准确度,减少因水位计测量不准、偏差大而引起的安全事故,对于提高涉网机组的安全性有较大的现实意义。     

丙烯酸聚乙二醇单酯的合成研究

以聚乙二醇-200与丙烯酸直接缩合反应,在不加有毒带水剂的条件下合成了丙烯酸聚乙二醇单酯。探讨影响缩合反应酯化率的因素,确定酯化反应的最佳条件：丙烯酸与PEG200的摩尔比为1.2∶1.0,反应温度是110-140℃,阻聚剂对苯二酚为0.6%（以醇酸总质量计）,反应时间为6 h,催化剂对甲苯磺酸为1.0%（以醇酸总质量计）,产率达89.4%。     

聚乙二醇重氮树脂在聚乙烯膜材料表面的自组装及亲水改性

用铬酸氧化法在聚乙烯薄膜的表面引入了羧基阴离子,合成了端基阳离子性的聚乙二醇重氮树脂,用静电自组装并辅以紫外光照射的方法,在聚乙烯薄膜的表面引入了共价键连接的聚乙二醇分子链.用紫外-可见分光光度法研究了重氮树脂及其静电自组装体系的光分解性质,得到重氮基团的分解速率常数kd=0.021 4 s-1.红外分析表明,紫外光照射后聚乙烯薄膜表面连接的聚乙二醇分子链可耐DMF-ZnC l2-H2O三元极性溶剂的刻蚀.由于在聚乙烯薄膜的表面引入了亲水性的聚乙二醇分子链,其表面接触角从改性前的104°降至48°.     

PMMA/PEG共混物形态和热性质的研究

在聚乙二醇存在的情况下,自由基聚合得到的聚甲基丙烯酸甲酯/聚乙二醇(PMMA/PEG)共混物,是一种半结晶聚合物;有相分离发生,一部分PEG晶体依然保持其晶体的特征,另一部分PEG晶体转变成非晶态,与PMMA网络复合,形成完全均一的非晶相。     

Water flux,DSC, and cytotoxicity characterization of membranes of cellulose acetate produced from sugar cane bagasse,using PEG 600

Summary In this article, cellulose acetate produced through the homogeneous acetylation of sugar cane bagasse cellulose was used to produce membranes, using poly(ethyleneglycol) 600 (PEG 600) as an admixture. The membranes were characterized using water flux measurements (Payne’s cup), differential scanning calorimetry (DSC) and neutral red uptake (cytotoxicity). The results showed that PEG 600 acts as a crystallinity inductor and/or pore former in the cellulose acetate matrix. The induction of crystallinity is important for this system since it had not been reported on the literature yet. The results also demonstrated that the studied membranes present a nontoxic behavior.     

固溶处理对Ti-600高温钛合金蠕变性能的影响

研究了固溶处理温度和随后的冷却方式对Ti-600高温合金蠕变性能的影响。结果表明,为了获得最佳的抗蠕变性能,宜采用相变点以上的温度进行固溶及随后空冷的处理制度,合金在600℃、150MPa条件下进行蠕变变形,主要受晶界滑动和晶内位错的滑移和攀移所控制。     

Application of enzymatically gelled chitosan solutions to water‐resistant adhesives

An investigation was undertaken on the application of dilute chitosan solutions gelled by tyrosinase‐catalyzed reaction with 3,4‐dihydroxyphenethylamine (dopamine). The tyrosinase‐catalyzed reaction with dopamine conferred water‐resistant adhesive properties to the semidilute chitosan solutions. The viscosity of the chitosan solutions increased highly by the tyrosinase‐catalyzed reaction and the subsequent reactions between o‐quinone compounds and chitosan. These highly viscous, gel‐like modified chitosan materials were allowed to spread onto the surfaces of the glass slides, which were tightly lapped together and held them in water. Tensile shear adhesive strength of over 400 kPa was observed for the modified chitosan samples. The increase in the amino group concentration of the chitosan solutions and the molecular mass of the chitosan used effectively led to the increase in adhesive strength of the glass slides. In addition, in the case where the chitosan solution was gelled by the enzymatic reaction with dopamine in the presence of poly(ethylene glycol), adhesive strength sharply increased at shorter reaction times concomitantly with the increase in the viscosity of the chitosan solutions because the tyrosinase activity effectively was retained by poly(ethylene glycol). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1818–1827, 2007