They were good catalyst for synthesis of n - butyl cinnamate.它们是催化合成肉桂酸正丁酯的良好催化剂.Butyl cinnamate was synthesized from cinnamic acid and butyl alcohol using tungstosilicic acid as catalyst.以钨硅杂多酸为催化剂,通过肉桂酸和正丁醇反应合成肉桂酸正丁酯.M...
钻石切割靠的是工匠的技艺。The cut of a diamond depends on the skill of its craftsman.有人偷了某个影星的钻石了吗?Has somebody helped himself to some film star's diamonds?他们被满橱窗陈列的钻石和皮草弄得眼花缭乱。They were dazed by window displays dripping with di...
Hypoid gear transmission is the most complicated transmission. The parameters of ma - chinking are hard to cakulate.准双曲面齿轮是齿轮传动中最复杂的, 其工艺锥参数和加工调整计算都涉及两个相错圆锥的相切接触条件.Fixtures are generally mechanical devices used to assist...