1. Department of Materials Science and Engineering, Tokyo Institute of Technology, Tokyo, Japan
2. Analytical and Measuring Instruments Division, Shimadzu Corporation, Kyoto, Japan
3. Bioceramics Group, RCFM, National Institute for Materials Science, Tsukuba, Japan
4. Department of Applied Chemistry, Meiji University, Tama-ku, Kawasaki-shi, Japan
5. Section of Bioengineering, Department of Dental Engineering, Fukuoka Dental College, Fukuoka, Japan
6. Tokyo Branch, Applied Electronics Laboratory, Kanazawa Institute of Technology, Tokyo, Japan