Liu, Feng http://orcid.org/0000-0002-4177-9845
Zhang, Pu
Funding for this research was provided by:
NNSF of China (11701333, 11571160)
Support Program for Outstanding Young Scientific and Technological Top-notch Talents of College of Mathematics and Systems Science (Sxy2016K01)
Article History
Received: 20 November 2018
Accepted: 13 March 2019
First Online: 19 March 2019
Competing interests
: The authors declare that they have no competing interests.