Funding for this research was provided by:
National Natural Science Foundation of China (71501052)
Foundation of Department of Education of Guangdong Province (2014WQNCX073)
Foundation of Guangzhou affiliated university (1201431441)
Natural Science Foundation of Guangdong Province (2015A030310506)
Philosophy and Social Planning Program of Guangdong Province (GD16XGL38)
Philosophy and Social Planning Program of Guangzhou (2016GZQN32)