Department of Materials Science, Faculty of Engineering Science, Akita University, Akita, Japan
Department of Materials Science, Faculty of Engineering Science, Akita University, Akita, Japan
Copyright © 2018 Ayano Nakamura, Kenji Murakami et al. This is
an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any
medium, provided the original work is properly cited.