1. Department of Physics, Beijing Normal University, 100875 Beijing, China
2. Institute of Microstructures and Properties of Advanced Materials, Beijing University of Technology, 100124 Beijing, China
3. Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085 Beijing, China
4. School of Aerospace Engineering, Beijing Institute of Technology, 100081 Beijing, China