Funding for this research was provided by:
Jiangsu Natural Science Foundation of Youth (BK20160893)
Natural Science Foundation of Jiangsu Higher Education Institutions (16KJB170012)
Philosophy and Social Science Foundation of Jiangsu Higher Education Institutions (2016SJB630001)
Humanities and Social Sciences Foundation of Nanjing University of Posts and Telecommunications (NYY215017)
National Natural Science Foundation of China (41471135)
National Natural Science Foundation of China (41601411)