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.
Many of the world's leaders have already denounced this election as a sham.许多国家的领导人已经指责这次大选弄虚作假。Its patrician dignity was a picturesque sham.它的贵族的尊严只是一套华丽的伪装.And let's be clear the supposed alternative, nonprof...
在曲折蜿蜒的鹅卵石街道的两边，一把把阳伞为露天咖啡馆遮阴挡阳。Umbrellas shade outdoor cafes along winding cobblestone streets.装有阳伞的婴儿车a child's buggy fitted with a sunshade阳伞是用来遮挡阳光的.Parasols are used as a protection against the sun....
He chalked the message on the blackboard...他用粉笔将消息写在黑板上。The boys chalked out goalposts on the sports ground wall.男孩子们在运动场边的墙上用粉笔画上了球门柱.The team chalked up the ten victories against two defeats.该队赢10场输2场.Several important...