Affiliation: | 1. Polymer and Material Research Groups, Faculty of Science, Udon Thani Rajabhat University, Udon Thani, Thailand;2. Division of Chemistry, Faculty of Science, Udon Thani Rajabhat University, Udon Thani, Thailand;3. songkot_u@hotmail.com;5. songkot@udru.ac.th;6. Program in Physics, Faculty of Science, Udon Thani Rajabhat University, Udon Thani, Thailand |