Chemical basic concept is the refining and chemical knowledge distillation, chemical knowledge is a basic chemical building tools and the concept of vector.
化学基本观念是化学知识的提炼与升华，化学知识是构建化学基本观念的工具与载体。
2
The refining process of citral product from natural litsea cubeba was studied by means of vacuum batch distillation.
采用减压间歇精馏方法，对从天然产物山苍子油中提取柠檬醛产品的精制过程进行了研究。
3
The three main methods for high purity zinc preparation, including electrolytic method, vacuum distillation, zone refining, are summarized and compared in this paper.