1. Technology Research Association for Single Wall Carbon Nanotubes (TASC), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565,
Japan
2. Nanotube Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi,
Tsukuba, Ibaraki 305-8565, Japan
3. Japan Science and Technology Agency (JST), Honcho 4-1-8, Kawaguchi
332-0012, Japan