Funding for this research was provided by:
National Natural Science Foundation of China (61703074, 61433014, 61673086, 61673085)
the Science Promotion Programme of UESTC (Y03111023901014006)
Text and Data Mining valid from 2019-03-01
Received: 11 July 2018
Accepted: 27 January 2019
First Online: 1 March 2019
: The authors declare that they have no competing interests.