本论文研究了4,4-二氟二苯砜(DFDPS)的纯化及以此为原料制备功能单体3,3-二磺化-4,4-二氟二苯砜(SDFDPS)的制备条件,在合成了直连型磺化聚芳醚砜(SPAES)及交联型磺化聚芳醚砜(CSPAES)的基础上,通过两类聚合物与磺化聚酰亚胺(SPI)的复合处理,制备两类复合膜材料,并详细研究了复合膜的各种性能。结果表明,两类复合膜具有高稳定性和高电导率等优点。同时还初步研究了通过后交联处
After two years of investigation, the U.S. Intational Trade Commission (ITC) announced at the end of August that it would not enforce a ban on drones of Da Jian
随着水体富营养化加剧，藻类所引起的水污染问题已越来越引起人们的关注，蓝藻是目前已知产生毒素最多、对人类健康造成的危害最大的藻类。微囊藻毒素-LR(microcystins-LR，MC-LR)是有毒蓝藻细胞合成的二级代谢产物，是一种细胞内毒素。微囊藻毒素可影响鱼类的胚胎发育和生长，也可引起肝脏、肾脏等内部器官的病理变化，和导致鱼体的氧化损伤等。然而，有关微囊藻毒素对鱼类分子水平上的毒性效应的研究则很
Rwanda made a splash during the China Intational Fair for Trade in Services (CIFTIS) in Beijing. Interested business people flocked to its investment and trade
According to a recent online survey on socializing by Guangming Daily, of the 2,532 people polled, 97 percent reported that they often try to duck socializing i