a
Department of Physics, Kyungpook National University, Daegu 702-701, Korea
b
Division of Nano-Bio Technology, Daegu Gyeongbuk Institute of Science and Technology, Daegu 704-230, Korea
E-mail: sh2358@dgist.ac.kr
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Fax: +82-53-785-3439
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Tel: +82-53-785-3410
c
Mineral Resources Research Division, Korea Institute of Geoscience and Mineral Resources, Daejeon 305-350, Korea
d
School of Energy Engineering, Kyungpook National University, Daegu 702-701, Korea
E-mail: hwp@knu.ac.kr
;
Fax: +82-53-950-8979
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Tel: +82-53-950-8973