1. Department of Physics, Xiamen University, Xiamen 361005, People’s Republic of China
2. School of Informatics, Xiamen University, Xiamen 361005, People’s Republic of China
3. Leibniz-Institut für Polymerforschung Dresden, 01069 Dresden, Germany
4. Departments of Mathematics, Applied Physical Sciences and Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3250, United States