Funding for this research was provided by:
NSFC Joint Fund with Zhenjiang Integration of Informatization and Industrialization under Key Project (U1609218)
National Natural Science Foundation of China (61602277)
Natural Science Foundation of Shandong Province (ZR2016FQ12)
Article History
Received: 28 January 2019
Accepted: 10 June 2019
First Online: 8 July 2019
Competing interests
: The authors declare that they have no competing interests.