Funding for this research was provided by:
the China Postdoctoral Science Foundation (2018M641562)
the Natural Science Foundation of Hunan Province, China (2018JJ3229)
the Hunan Innovation and entrepreneurship training Foundation for undergraduates (S201910537057)
Article History
Received: 25 March 2020
Accepted: 14 May 2020
First Online: 18 June 2020
Compliance with ethical standards
:
: The authors declare that they have no conflicts of interest.
: This article does not contain any studies with human participants or animals performed by any of the authors.