Funding for this research was provided by:
National Natural Science Foundation of China (61275201, 61372037)
Beijing Excellent Ph.D. Thesis Guidance Foundation (20131001301)
National Key R&D Program of China (2016YFA0301300)
BUPT Excellent Ph.D. Students Foundation (CX2017401)
Text and Data Mining valid from 2018-05-10
Received: 25 January 2018
Accepted: 30 April 2018
First Online: 10 May 2018
: The authors declare that they have no competing interests.
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