Quantity of water solubilization by rust inhibitors was calculated based on the phase digram.

在相图测础上,计算出防锈剂对水增溶度。

It is a difficult thing for our student to draw a block digram according to a principle digram,the difficulties are analysed and some good methods are also given in this article.

以一道为例，对绘制框图时几个难点进行了较分析，给出了克服困难方法.