[1] RIKEN, Inst Phys & Chem Res, Hirosawa 2-1, Wako, Saitama 35101, Japan
[2] Mitsui Min & Smelting Co Ltd, Corp R&D Ctr, Haraichi 1333-2, Ageo, Saitama 362, Japan
[3] Tokyo Denki Univ, Hatoyama, Saitama 35003, Japan
[4] Shimadzu Corp, Keihanna Res Lab, Seika, Kyoto 61902, Japan
[5] Minist Posts & Telecommun, Commun Res Lab, Nukuikitamachi 4-2-1, Koganei, Tokyo 184, Japan