1. Department of Electronic Science Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance State Key Laboratory of Physical Chemistry of Solid Surfaces Xiamen University P.O.Box 979 Xiamen 361005 China
2. School of Computer and Information Engineering Xiamen University of Technology China
3. Department of Molecular Sciences Swedish University of Agricultural Sciences Uppsala Sweden
4. Department of Chemistry and Molecular Biology University of Gothenburg Box 465 Gothenburg 40530 Sweden