Funding for this research was provided by:
National Natural Science Foundation of China (11626029, 71804001)
Anhui Province Philosophy and Social Science Planning Fund Office (AHSKQ2017D03)
Article History
Received: 19 October 2019
Accepted: 6 February 2020
First Online: 18 February 2020
Competing interests
: The authors declare that they have no competing interests.