1. INAMORI Frontier Research Center Kyushu University 744 Motooka Fukuoka 819‐0395 Japan
2. Department of Materials Science and Engineering Kyushu University 744 Motooka Fukuoka 819‐0395 Japan
3. Department of Environmental Robotics University of Miyazaki 1‐1 Gakuenkibanadai‐nishi Miyazaki 889‐2192 Japan
4. Kyushu University Platform of Inter‐/Transdisciplinary Energy Research Kyushu University 744 Motooka Fukuoka 819‐0395 Japan