Text and Data Mining valid from 2019-11-06
Received: 6 August 2019
Accepted: 31 October 2019
First Online: 6 November 2019
Compliance with ethical standards
: We hereby pledge that this study is a true scientific research of my own, conducted under my research group. The references in the manuscript are from scientific papers, books have been verified and published widely. We promise to quote the source clearly in the reference list. The research results in this project are done by the group itself strictly, honestly and not overlapping with other topics.