simple process factor

The product of purification factor and recovery yield is used as the objective function for optimizing a single step process.

单级过程的优化目标函数（Ｆ１）为ＲＥＣ和ＰＦ的积，而多级过程则将获得一定纯度的目标组分情况下的回收率和ＣＡＲＥ级数之比为优化目标函数Ｆ２。