Funding for this research was provided by:
China Postdoctoral Science Foundation (2016M592819)
National Natural Science Foundation of China (51704226, 51674191)
Natural Science Basic Research Plan in Shaanxi Province of China (2017JQ5047)
Scientific Research Program Funded by Shaanxi Provincial Education Department (17JK0500)
Article History
Received: 12 September 2017
Accepted: 7 December 2017
First Online: 29 January 2018