Funding for this research was provided by:
Innovative Research Group Project of the National Natural Science Foundation of China (51205328)
Youth Foundation for Humanities and Social Sciences of Ministry of Education of China (18YJC630255)
Sichuan Science and Technology Program (2019YFG0285)
Article History
Received: 4 July 2019
Accepted: 3 December 2019
First Online: 18 December 2019
Compliance with ethical standards
:
: No potential conflict of interest was reported by the authors.