1. Piezoelectric Research Laboratory, Center of Excellence on Alternative Energy, Research and Development Institution, Sakon Nakhon Rajabhat University, Sakon Nakhon, Thailand
2. Programs of Physics, Faculty of Science and Technology, Sakon Nakhon Rajabhat University, Sakon Nakhon, Thailand
3. Research and Development Institution, Sakon Nakhon Rajabhat University, Sakon Nakhon, Thailand