1. Division of Physical Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand
2. Division of General Education, National Institute of Technology (KOSEN), Nagaoka College, 888 Nishikatakai-machi, Nagaoka-shi, Niigata, 940-8532, Japan
3. Graduate School of Science and Technology, Niigata University, 8050, Ikarashi 2-nocho, Nishi-ku, Niigata 950-2181, Japan