1. State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, China
2. Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
3. Key Laboratory of Ministry of Education for Advanced Materials in Tropical Island Resources, College of Materials and Chemical Engineering, Hainan University, Haikou, China
4. Ames Laboratory-U.S. Department of Energy, and Department of Physics and Astronomy, Iowa State University, Ames, IA, USA