Funding for this research was provided by:
the ‘BLUE POINT’ project of Lu’an Mining Group and Graduate Innovation Program of Shanxi Province (No. 2016BY052)
Natural Science Foundation of Shanxi Province (No. 201801D121056)
Key Research and Development Project of Shanxi Province (No. 201803D421011)
National Natural Science Foundation of China (U1510203)
Article History
Received: 10 January 2020
Accepted: 30 August 2020
First Online: 8 September 2020
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.