Institute of Biophysics and Department of Physics, Central China Normal University, Wuhan, China.|Department of Physics, The George Washington University, Washington, DC, USA.|Institute of Biophysics and Department of Physics, Central China Normal University, Wuhan, China.|Institute of Biophysics and Department of Physics, Central China Normal University, Wuhan, China.|Institute of Biophysics and Department of Physics, Central China Normal University, Wuhan, China.