环保型固体文具胶的制备

以聚醋酸乙烯、聚乙烯醇、硬脂酸钠、甘油、乙二醇等为原料，制得一系列固体胶棒。通过对其粘性、涂希l生、赋形性等使用性能测试比较，得出了一种环保型固体文具胶最佳配方。探讨了凝胶剂、胶粘剂、改性助剂、保湿剂、溶剂等组份对固体文具胶使用性能的影响。研究结果表明：聚醋酸乙烯乳液和聚乙烯醇共混改性生产固体文具胶，原料均环保无污染，且全部转化为产品，无三废生成。在最佳工艺条件下生产的产品，具有赋形性好，初始粘性强，粘接强度高，涂布性能好，适应温度范围宽，成本低，无毒的特点。     

铜表面微蚀处理新技术

采用过硫酸盐和几种特别添加剂配制成的微蚀剂,不仅具有传统微蚀剂的优点,而且拥有其独特的优点:微蚀处理的铜表面比传统微蚀剂处理的光亮;微蚀处理后暴露在空气中10 min,铜表面也不变色;微蚀处理后的元件没有原电池腐蚀现象发生;其工作溶液比传统微蚀剂稳定;微蚀速率容易控制以满足不同的微蚀要求;微蚀处理不影响精密线路板和元件的尺寸。     

从硬质合金典型材质发展看中国硬质合金工业的技术进步

中国是世界硬质合金的生产与消耗大国,中国硬质合金工业的技术现状令世人关注.本文从硬质合金典型材质与关键原料制备技术及其微观组织结构与性能特性等方面,展示了近年来中国硬质合金工业的主要技术进展.包括紫钨工艺制备的超细、纳米W粉与WC粉,紫钨工艺与WC-Co纳米复合粉工艺制备的超细晶硬质合金,超粗晶硬质合金以及原位激发自润...     

Seasonal variation in the role of grey squirrels as hosts of Ixodes ricinus, the tick vector of the Lyme disease spirochaete, in a British woodland

The partition of free fatty acids (FFA) to egg-phosphatidylcholine (egg-PC) and egg-phosphatidylethanolamine (egg-PE) vesicles was studied. Upon the addition of FFA to the suspension of vesicles, the pH of the aqueous phase changed depending on the length and saturation of the FFA hydrocarbon chain, as well as on the vesicle composition. The medium pH decreased faster if FFA was added to egg-PE as compared to egg-PC vesicles. The fluorescent free fatty acid indicator (ADIFAB) was used to measure the amount of FFA remaining in the aqueous phase. Most of the FFA added to the suspension of egg-PE vesicles remained in the aqueous phase, whereas in the presence of egg-PC vesicles the FFA partitioned preferentially into the lipid phase. The amount of FFA incorporated into the lipid bilayers was estimated by measuring the changes of pH at the lipid bilayer surface, using fluorescein-PE. At high surface concentrations of FFA, decreasing pH at the bilayer surface caused the protonation of FFA, and raised the pK of FFA at the bilayer surface from 5 to about 7. The partition of FFA in egg-PE vesicles was an order of magnitude lower than that in egg-PC vesicles. The incorporation amount was determined more by the molecular packing than by the nature of lipid headgroups, because steroylcaprioyl-PE, which preferred the bilayer structure, behaved more like egg-PC than egg-PE. Understanding FFA partition characteristics would help to interpret the hydrolysis measurements of phospholipids, and to explain many biological activities of FFA.     

机载航电系统通用ATS设计

文章从软硬件两方面讨论了机载航电系统通用ATS的设计方法.该系统以VXI总线模块、GPIB台式仪器硬件平台为依托,以ABBET标准软件结构为基础,采用格式化接口函数、仪器可互换和TPS可移植性技术,实现了机载航电系统ATS的标准化和通用化.     

无荷载状况下泡沫混凝土裂缝控制的研究

研究了水胶比、粉煤灰、PP纤维和高性能膨胀剂对无荷载状况下泡沫混凝土力学性能、收缩性能的影响.结果表明,泡沫混凝土在水化中后期表现为收缩的特征;在水胶比为0.3～0.5时,水胶比越大,最终泡沫混凝土的收缩越小,当水胶比大于0.5或小于0.2时,28 d收缩量都减小.乱向分布的纤维可以略微减小泡沫混凝土的收缩;一定掺量的膨胀剂可以有效地补偿泡沫混凝土变形收缩,在水化早期实现泡沫混凝土无收缩.     

利用废弃混凝土制备半干压成型砖的研究

利用废弃混凝土制备了半干压成型砖,研究了养护制度和碱激活对半干压成型砖性能的影响.结果表明,随着养护温度的提高,半干压成型砖的强度逐渐增大;养护温度越高,半干压成型砖的最大强度也越高,达到最高强度所需的时间越短;当养护时间达到一临界值后,强度不再增长.碱激发可提高半干压成型砖的早期强度,但对半干压成型砖的后期强度没有影响.制备的半干压成型砖抗压强度和抗冻性等指标能够满足相关标准的要求,表明利用废弃混凝土制备半干压成型砖是可行的.