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 ).Surface active propertie...
不过，缺乏的是一种内在的艺术凝聚力。What is missing, however, is an internal, artistic cohesion.他们给他验了血，以检查是否有维生素缺乏的迹象。They did blood tests on him for signs of vitamin deficiency.认为老年人性缺乏的倾向the tendency to see old people as asexual...