1. Department of Materials Science and Engineering; National Tsing Hua University; Hsinchu 30013 Taiwan R. O. C.
2. Department of Mechanical and Automation Engineering; I-Shou University; Kaohsiung 84001 Taiwan R. O. C.
3. National Institute for Materials Science; Sengen 1-2-1, Tsukuba Ibaraki 305-0047 Japan