Xie, Duan
Zhao, Jian
Funding for this research was provided by:
the National Natural Science Foundation of China (61306131)
the Science Foundation of Shaanxi Provincial Department of Education (14JK1682)
Article History
Received: 4 November 2017
Revised: 28 November 2017
Accepted: 5 December 2017
First Online: 13 December 2017