1. Analysis Research Department, Advanced Technology Research Center, NKK Corporation (Nippon Rokan), 1-1, Minamiwatarida-cho, Kawasaki-ku, Kawasaki 210, Japan (M.K., H.M., N.G.); and Industrial Chemistry, Faculty of Engineering, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 213, Japan (Y.G.)