Funding for this research was provided by:
Fundamental Research Funds for Central Universities of Central South University (2019zzts693, 2018zzts803)
Text and Data Mining valid from 2019-08-08
Received: 18 May 2019
Accepted: 5 August 2019
First Online: 8 August 2019
Compliance with ethical standards
: There are no conflicts of interest in the submission and the work described was original research that has not been published previously. All authors have consulted the “Information for Authors” and approved to submit this manuscript.