N - hydroxyethylpyrrolidone ( NHP ) was synthesized from � � - butyrolactone and ethanolamine on Y molecular sieve catalyst by two steps. 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 ).
Only the opening sequence could claim to be genuinely innovatory.只有开场片段能称得上是真正的创新。He described the sequence of events leading up to the robbery.他描述了抢劫案发生前的一系列有关情况。a time-lapse sequence of a flower opening一组延时拍摄花蕾开放的镜头...
Ronald: I'm in a lot of pain. I have a toothache.罗讷德: 我很痛苦, 我的牙很痛.P : The forehead. Sometimes I also have a toothache.前额部. 有时牙齿也疼.You always ( have ) a toothache ( brcause ) you ( eat ) too ( much ) spicy food.你总是牙疼...