The National Natural Science Foundation of China(11271235);the Development Foundation of Higher Education Department of Shanxi Province(20111117,20111020);Reseach Fund Project of Shanxi Datong University(2016K9,2017K4)
supported by National Natural Science Foundation of China(11271235);Shanxi Datong University(2009-Y-15,2010-B-01);the Development Foundation of Higher Education Department of Shanxi Province(20111020)