以改性Y分子筛为催化剂,γ-丁内酯和乙醇胺为原料,采用γ - 丁内酯法两步合成N - 羟乙基吡咯烷酮 ( NHP ). N - hydroxyethylpyrrolidone ( NHP ) was synthesized from � � - butyrolactone and ethanolamine on Y molecular sieve catalyst by two steps.
This skein of wool won't disentangle.这束毛线解不开.Doctors discovered the hematoma by using a special computer X - ray called a " ket - skein ".医生们使用了一种叫 “ 铜束 ” ( ket -skein)的特别的电脑x光机,检查出了脑血肿的准确位置.The packaging varies fro...
At the swimming pool I put my clothes in a locker.在游泳池我把衣服锁在小柜里.A man in the gangway suddenly stood up to reach for something in the overhead locker.靠通道坐的一名男子突然起身去拿头顶上方行李舱里的什么东西。It was George who first proposed that we d...
The representation theorem with order - extremal points is obtained for compact order - convex sets.研究了序凸集的一些运算性质,得到了紧序凸集的序端点表示定理.Finally, the Bahadur asymptotic efficient est imator is constructed through extremal stati...