Funding for this research was provided by:
National Social Science Foundation of China (16BGL024)
Sichuan Province System Science and Enterprise Development Research Center (Xq16C13)
Fundamental Research Funds for the Central Universities (YJ202015, 2020ZY-SX-C01)
Article History
Received: 1 March 2020
Revised: 24 June 2020
Accepted: 23 September 2020
First Online: 30 October 2020
Compliance with ethical standards
:
: The authors declare no conflict of interest.