1. Graduate School of Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan
2. Technology Development Devision, TOKYO GAS Co., Ltd., 2-7, Suehirocho 1, Tsurumiku, Yokohama 230-0045, Japan
3. Research Center for Exotic NanoCarbon Project, Shinshu University, 4-17-1, Wakasato, Naganoshi 380-8553, Japan