1. Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, 1‐1‐1, Nojihigashi, Kusatsu, Shiga 525‐8577 (Japan), Fax: (+81) 77‐561‐2659
2. Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), CNRS‐Université de Strasbourg (UMR 7504), 23, rue du Loess, BP 43, 67034 Strasbourg Cedex 2 (France)
3. Institute for Materials Chemistry and Engineering, Kyushu University, 6‐1, Kasuga‐koen, Kasuga, Fukuoka 816‐8580 (Japan), Fax: (+81) 92‐583‐7789