Yoshiyuki ABE†, Kazuyuki KAKEGAWA*†† and Yoshinori SASAKI††
Department of Mathematics and Physical Sciences, Graduate School of Science and Technology, Chiba University; 1-33 Yayoi-cho, Inage-ku, Chiba-shi 263-8522 Japan † Present address: Sumitomo Metal Mining Co., Ltd.; 3-18-5, Nakakokubun, Ichikawa-shi 272-8588 Japan †† Department of Applied Chemistry, Faculty of Engineering, Chiba University; 1-33 Yayoi-cho, Inage-ku, Chiba-shi 263-8522 Japan