Yan, Zuomao
Jia, Xiumei
Funding for this research was provided by:
the National Natural Science Foundation of China (11461019)
the President Found of Scientific Research Innovation and Application of Hexi University (xz2013-10)
the President Fund of Scientific Research Innovation and Application of Hexi University (XZ2014-22)
the Scientific Research Project of Universities of Gansu Province (2014A-110)