利用化学方法,由外消旋环氧氯丙烷出发,合成丁酸环氧丙酯,精制后可获得纯度96%以上的丁酸环氧丙酯,收率为47%。
Glycidyl butyrate was synthesized from racemic epichlorohydrin and butyric acid by chemical means. The purity of the refined product was over 96% and the yield was about 47%.
尽管,许多卫星在36000千米处形成一个类似土星光环的环,但这个高度的卫星都需要花费24小时绕地球一圈。因此,它们一直在地球上空的同一点盘旋。
Many, though, form a ring like Saturn's at a distance of 36,000km, the place at which an object takes 24 hours to orbit the Earth and thus hovers continuously over the same point of the planet.
有着与众不同的中心恒星环,旋臂上还点缀着大量炽热的年轻恒星组成的蓝巨星簇,NGC 1097就成为绝佳的观测目标。
With this distinctive central star-forming ring, and the addition of numerous bluish clusters of hot, young stars dotted through its spiral arms, NGC 1097 makes a stunning visual object.
应用推荐