1. Laboratory of Applied Clay Technology, Hojun Co., Ltd., An-naka, Gunma 379-0133, Japan
2. Advanced Institute of Materials Science, 2-6-8 Moniwadai, Taihaku, Sendai, Miyagi 686-0252, Japan
3. Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), 162-1 Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan