Jiao, Yujuan
Zeng, Wenjing
Funding for this research was provided by:
Science and Technology Planning Project of Gansu Province (1610RJZA102)
Fundamental Research Funds for the Central Universities (31920170147,31920180116)
the First-class Discipline Program of Northwest Minzu University
Article History
Received: 20 January 2018
Accepted: 6 June 2018
First Online: 15 June 2018
Competing interests
: All of the authors of this article claim that together they have no competing interests.