Department of Space Science and Applied Physics Shandong University at Weihai Weihai 264209 China;
School of Physics and SK Lab. of Nucl. Phys. & Tech. Peking University Beijing 100871 China;
Institute of Theoretical Physics Chinese Academy of Science Beijing 100080 China;
Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 730000 China;
Department of Physics University of Stellenbosch Stellenbosch South Africa;