环乙烯

基于α-肉桂酰环乙烯酮二硫缩酮的一类新型D-A有机发光材料的理论

Theoretical Investigation on Novel Donor-acceptor Materials with Organic Light-emitting Diodes Based on α - Cinnamoyl Cyclic Ketene Dithioacetals

虽然这两种生物碱都含环外乙烯基，Nb-甲基及可能具环醚结构，但是其脂环部分的构造按推断亦不相同。

Although gelsemine and koumine both contain an exo-vinyl , an Nb-methyl and most likely a cyclic ether linkage , the structures of the alicyclic parts of these two alkaloids appear also different from each other .

环丙烯类乙烯作用抑制剂在园艺产品采后保鲜上的应用

Applications of ethylene action inhibitors of cyclopropenes on postharvest freshness protection of horticultural products

活塞密封用O形环、聚四氟乙烯挡圈及铍青铜三角环。

The pistons are sealed with O rings , teflon backup rings and bevelled berylco rings .