1. Institute of Industrial Science, University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8505, Japan, Koyo Engineering Co., Ltd., 2-880 Takaragimachi, Utsunomiya, Tochigi 320-0061, Japan, and Department of Applied Chemistry, School of Engineering, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan