Funding for this research was provided by:
National Natural Science Foundation of China (61503424)
Beijing Polytechnic (YZK2015013, CJGX2016-SZ-05/008, 02362050301)
Article History
Received: 29 May 2018
Revised: 14 November 2018
Accepted: 19 November 2018
First Online: 7 December 2018