1. Institute of Natural Sciences and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
2. Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA.
3. Center for Molecular Biophysics, Oak Ridge National Laboratory, TN 37831, USA.
4. Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA.
5. NIST Center for Neutron Research, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA.
6. Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA.