Yan, Zuomao
Lu, Fangxia
Funding for this research was provided by:
the National Natural Science Foundation of China (11461019)
the President Fund of Scientific Research Innovation and Application of Hexi University (xz2013-10)
the Scientific Research Fund of Young Teacher of Hexi University (QN2015-01)
Article History
Received: 19 July 2017
Revised: 3 January 2018
First Online: 2 March 2018