Funding for this research was provided by:
National Natural Science Foundation of China (11625101)
National Natural Science Foundation of China (11771338)
Natural Science Foundation of Zhejiang Province (LY17A010010, LY15A010015)
Natural Science Foundation of Zhejiang Province (LY15A010016)
Division of Mathematical Sciences (1418934)
National Natural Science Foundation of China (91430213, 11421101)
National Natural Science Foundation of China (11671304)
Wenzhou Science and Technology Plan Project (G20160019)
Article History
Received: 3 August 2016
Revised: 17 August 2017
Accepted: 21 December 2017
First Online: 17 January 2018