New catalysts combined with an organic or inorganic lithium salt (lithium acetate or lithiumchloride) and a conventional catalyst for the transesterification of
This paper proposes a new computer aided pattern design system(CAPDS)in which a uniformmathematical expression is used to construct different objects. In the ge
[英语原文] One day,the teacher inquired Peter:“How much is four minus four?”Peter was tongue-tired. The teacher got angry and said:“What a fool! You see, if I put four coins in vour pocket, but there is