1. Department
of Applied Chemistry and Biotechnology, Chiba University, 1-33
Yayoi, Inage, Chiba 263-8522, Japan
2. National
Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8561, Japan
3. National
Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
4. Department
of Physics, University of California at Berkeley, Berkeley, California 94720, United States