**Acknowledgements**

The authors would like to express their gratitude to Okabe T. (LPS-Works Co., Ltd.), Yoshino T. (Komatsu-Seiki Kosakusho, Co., Ltd.), Hasegawa T., Miyagawa T. (Graduate School of Engineering, Shibaura Institute of Technology), and Kurozumi S. (Nano-Film Coat) for their help in experiments.
