Zou, Qingyun
Wang, Guoqiu
Cao, Qian
Funding for this research was provided by:
the Natural Science Foundation of Hunan Province (16JJ6102)
the Outstanding Youth Foundation of Hunan Province Department of Education (17B182)
the Doctoral Foundation of Hunan University of Arts and Science (15BSQD02)
the College Students Research Study and Innovative Experiment Project of Hunan Province (17541)
Article History
Received: 11 October 2017
Accepted: 3 February 2018
First Online: 17 February 2018
Competing interests
: The authors declare that they have no competing interests.