1. Department of Aeronautics and Astronautics, Kyushu University, Nishi-Ku, Motooka 744, Fukuoka 819-0395,
Japan
2. International Institute for Carbon-Neutral Energy Research
(WPI-I2CNER), Kyushu University, Nishi-Ku, Motooka 744, Fukuoka
819-0395, Japan