1. Insulation Materials Research Center, Korea Electrotechnology Research Institute (KERI), Changwon 51543, Korea
2. Department of Aeronautical and Aviation Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
3. Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong