Funding for this research was provided by:
National Natural Science Foundation of China (81571507)
Hunan Province Enterprise Technical Renovation Project Funding (2015)
Text and Data Mining valid from 2020-04-07
Received: 14 December 2019
Accepted: 27 March 2020
First Online: 7 April 2020
Ethics approval and consent to participate
: Not applicable.
: All authors provided final approval of the version to be published and agree to be accountable for all aspects of the work in ensuring that questions.
: The authors declare that they have no competing interests.