1. Department of Metallurgical Engineering, Inha University, Incheon 402-751, Republic of Korea
2. Light Metal Division, Korea Institute of Materials Science, Changwon 642-831, Republic of Korea
3. Department of Biological Engineering, Inha University, Incheon 402-751, Republic of Korea
4. Institute of Research & Technology, Daechang Co., Ltd., Siheung 429-794, Republic of Korea