1. a Institute of Materials Science and Engineering , National Sun Yat-sen University , Taiwan, Kaohsiung, Republic of China
2. b Department of Materials Science and Engineering , National Dong Hwa University , Taiwan, Hualien, Republic of China
3. c Central Geological Survey , P.O. Box 968, Taipei, Taiwan, Republic of China
4. d Institute of Earth Sciences , Academia Sinica , Taipei, Taiwan, Republic of China