Funding for this research was provided by:
National Natural Science Foundation of China (61472374, 71503096)
China university of geosciences (Wuhan) graduate quality textbook construction project (YJC2017405)
Article History
Received: 24 March 2019
Accepted: 21 May 2019
First Online: 6 August 2019
Competing interests
: The authors declare that they have no competing interests.