Funding for this research was provided by:
National Natural Science Foundation of China (No. 31501467)
Fundamental Research Funds for the Central Universities (No. 2452016086)
Shaanxi Province Key Research and Development Plan (No. 2017NY-157)
Article History
Received: 25 April 2018
Accepted: 3 July 2018
First Online: 13 July 2018
Compliance with Ethical Standards
:
: All authors have read and agreed with the contents of the manuscript. The authors indicate no potential conflicts of interest.