Funding for this research was provided by:
the Program for the Philosophy and Social Sciences Research of Higher Learning Institutions of Shanxi No.201 (2016 (39))
Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province (2016 (3))
Article History
Received: 18 June 2019
Accepted: 20 May 2020
First Online: 27 May 2020
Compliance with ethical standards
:
: The authors declare that there is no conflict of interest regarding the publication of this manuscript.