Acknowledgements
We thank Science club students in Nakadai Junior high school,
Hidehiro Hoshiba, Hitomi Enomoto, Atsushi Watanabe, Manabu
Egawa, Hiroyuki Koishi, Koji Iizuka, Norio Abe, Adam Rolander
and Shawn Lynott. This work was supported by Grants-in-Aid
for Scientific Research from Japan Society for the Promotional
Science and was partly supported from Nissan Science
Foundation.