Emperor Shunzhi forbid the Hans in central China to reclaim wasteland in the Mongolian area so that the migrants might come back to their own land and reclaim it again and therefore would be a source of taxes and penal labour .

Study on evaluating-diversity of two kinds of five-rating qualifiers;

A skewed control chart and its optimal design model is constructed using weight variation method since the asymmetry of non-normal data cannot be solved effectively by usual control chart.

Aiming at the problem that the asymmetry of non-normal data cannot be solved effectively by general control chart,weight variation method is used to construct asymmetry control chart,and then an optimal design model is built.