Funding for this research was provided by:
National Natural Science Foundation of China (51675495)
National Natural Science Foundation of China (61703374)
Fundamental Research Funds for the Central Universities, China University of Geosciences (CUG150609)
Fundamental Research Funds for the Central Universities, China University of Geosciences (CUG170656)
Article History
Received: 11 July 2018
Accepted: 11 January 2019
First Online: 24 January 2019
Compliance with ethical standards
:
: The authors declare that there is no conflict of interest.