1. Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 567-0871, Japan
2. Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
3. Technology and Innovation Center, Daikin Industries, LTD., 1-1 Nishihitotsuya, Settsu, Osaka 566-8585, Japan
4. Air Conditioning Manufacturing Division, Daikin Industries, LTD., 3-12 Chikkoshinmachi, Nishi Ward, Sakai, Osaka 592-8331, Japan