PP/PS-海泡石插层纳米复合材料的流变性能与形态结构

采用苯乙烯乳液聚合法对有机海泡石原位插层,将插层产物聚苯乙烯(PS)-海泡石与聚丙烯(PP)熔融共混制备PP/PS-海泡石插层纳米复合材料.流变测试结果表明:PP/PS-海泡石插层纳米复合材料为典型的假塑性流体,其偏离牛顿流体的程度随PS-海泡石含量增加而增大,表观黏度和零切黏度随着PS-海泡石含量的增加而减小,PS-...     

Modulation of Ca Signals by Epigallocatechin-3-gallate(EGCG) in Cultured Rat Hippocampal Neurons

Green tea has been receiving considerable attention as a possible neuroprotective agent against neurodegenerative disease. Epigallocatechin-3-gallate (EGCG) is the major compound of green tea. Calcium signaling has profound effects on almost all aspects of neuronal function. Using digital calcium imaging and patch-clamp technique, we determined the effects of EGCG on Ca(2+) signals in hippocampal neurons. The results indicated that EGCG caused a dose-dependent increase in intracellular Ca(2+) ([Ca(2+)](i)). This [Ca(2+)](i) increase was blocked by depleting intracellular Ca(2+) stores with the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin and cyclopiazonic acid. Furthermore, EGCG-stimulated increase in [Ca(2+)](i) was abolished following treatment with a PLC inhibitor. However, EGCG inhibited high-voltage activated Ca(2+) currents (I(HVA)) and NMDA-induced inward currents (I(NMDA)). These data suggest that EGCG triggers a cascade of events: it activates phospholipase C (PLC), mobilizes intracellular Ca(2+) stores, raises the cytosolic Ca(2+) levels, and inhibits the VGCC and NMDA receptors-mediated Ca(2+) influx through a process that remains to be determined.     

电子体温计外壳注射模具设计

本文分析了电子的温度计外壳使用要求与结构特点,介绍了模具的总体结构特点及模具的动作原理,研究分析了设计模具零件结构参数的合理性,既保证了外壳产品的成型性和使用性,又使得模具结构简单,模具零件便于加工。     

High-density gold nanowire arrays by lithographically patterned nanowire electrodeposition

Here we describe a new method for preparing multiple arrays of parallel gold nanowires with dimensions and separation down to 50 nm. This method uses photolithography to prepare an electrode consisting of a patterned nickel film on glass, onto which a gold and nickel nanowire array is sequentially electrodeposited. After the electrodeposition, the nickel is stripped away, leaving behind a gold nanowire array, with dimensions governed by the gold electrodeposition parameters, spacing determined by the nickel electrodeposition parameters, and overall placement and shape dictated by the photolithography.     

气相色谱法检测食用菌中八氯二丙醚的残留量

建立了一种测定食用菌中八氯二丙醚(S-2)残留量的气相色谱方法.样品中的八氯二丙醚经丙酮-正己烷混合溶剂提取,浓硫酸液-液分配磺化法进行净化,以气相色谱法(GC-ECD)测定,外标法定量.实验结果表明:样品中加入0.005～0.05mg/kg浓度水平的S-2,回收率在72.4%～104.4%之间,相对标准偏差小于7.8...     

淮南矿区液压支架配液水质研究及使用建议

通过对淮南矿区液压支架配液水质特点的分析研究,结合MT76-2002标准要求对淮南矿区配液水质的正确使用提出了建议,并对高矿化度矿井水的使用提出了解决方案。     

废胎面胶粉的生物脱硫与化学脱硫效果对比

分别用酵母茵和Delink脱硫剂对废胎面胶粉(GTR)进行生物脱硫和化学脱硫,研究了酵母茵的生长情况,考察了脱硫胶粉对其填充丁苯橡胶(SBR)硫化胶交联密度、物理机械性能和动态力学性能的影响,并对填充硫化胶的相态结构进行了表征.结果表明,加入GTR后,酵母菌的生物量略有下降,但经过4 d后仍能维持较高的生物量水平;生物...     

c—SiC—B4C复合材料的制备及其抗氧化性能研究

以生石油焦为炭质原料,向其中掺入定量SiC、B4CN瓷相,以改质煤焦油沥青作为粘结剂,通过模压制备出C—SiC—B4C复合材料。通过XRD、SEM、DTA—TG、EDS等分析方法研究了SiC、B4CNJ瓷相对C—SiC—B4C复合材料结构和性能的影响。研究表明,C—SiC—B4C复合材料的高温抗氧化性与氧化温度、各陶瓷相含量、本身气孔率等有关。掺入的Sic、B4C能够在一定程度上降低炭材料的气孔率,同时,高温条件下陶瓷相形成硼硅酸玻璃覆盖炭基体表面,减少材料表面活性区域数量,提高炭材料的表观活化能。     

一种新型防治橡胶树主要叶部病害热雾剂的研制

研制了一种由有效成分、溶剂、助溶剂和表面活性剂组成的30%嘧·咪·酮热雾剂,可有效防治橡胶树主要叶部病害。实验流程是对三唑酮、咪鲜胺和嘧菌酯3种有效成分进行溶解试验,并根据溶剂的溶解性能以及热雾剂使用时的闪点、粘度等因素,筛选出了2种溶剂。将2种溶剂按一定比例配合,达到热雾剂使用的国家标准。根据多种表面活性剂的理化性质,筛选出具有不同性能的3种表面活性剂。最终,研制出1种由3种有效成分、2种溶剂和3种表面活性剂组成的新型热雾剂,可用来防治橡胶树主要病害。     

中国六面顶压机大型化的快速发展及相关问题(上)

文章回顾了压机大型化的历史阶段与特点,指出了成果与存在的问题,阐述了这些问题都是当前金刚石行业中极为重要的问题,值得决策者重视.