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Sekine, Yurina; Kobayashi, Riki*; Chi, S.*; Fernandez-Baca, J. A.*; Suzuya, Kentaro; Fujisaki, Fumika*; Ikeda, Kazutaka*; Otomo, Toshiya*; Fukazawa, Tomoko*; Yamauchi, Hiroki; et al.
JPS Conference Proceedings (Internet), 8, p.033009_1 - 033009_6, 2015/09
Neutron diffraction profiles of low-D
O-content poly-N,N,-dimethylacrylamide (PDMAA) hydrogels were measured from 100 to 300 K to investigate the structure and properties of water in hydrogels. A broad diffraction observed at temperatures lower than 220 K indicates the existence of amorphous ice in the hydrogels at low temperatures. During the heating process, diffraction peaks from ice crystals appear in the profiles. These peaks indicate that cubic ice and hexagonal ice exist at T 
220 K. We refined the structure parameters of these ices in the hydrogel, which indicate the existence of low-density ice in the hydrogel.
Al
Kobayashi, Riki*; Kaneko, Koji; Saito, Kotaro*; Mignot, J.-M.*; Andr
, G.*; Robert, J.*; Wakimoto, Shuichi; Matsuda, Masaaki*; Chi, S.*; Haga, Yoshinori; et al.
Journal of the Physical Society of Japan, 83(10), p.104707_1 - 104707_5, 2014/10
Times Cited Count：17 Percentile：69.54(Physics, Multidisciplinary)Mitamura, Hiroyuki*; Watanuki, Ryuta*; Kaneko, Koji; Onozaki, Norimichi*; Amo, Yuta*; Kittaka, Shunichiro*; Kobayashi, Riki*; Shimura, Yasuyuki*; Yamamoto, Isao*; Suzuki, Kazuya*; et al.
Physical Review Letters, 113(14), p.147202_1 - 147202_5, 2014/10
Times Cited Count：23 Percentile：75.83(Physics, Multidisciplinary)Sekine, Yurina; Fukazawa, Tomoko*; Aizawa, Mamoru*; Kobayashi, Riki*; Chi, S.*; Fernandez-Baca, J. A.*; Yamauchi, Hiroki; Fukazawa, Hiroshi
Journal of Physical Chemistry B, 118(47), p.13453 - 13457, 2014/08
Times Cited Count：2 Percentile：3.69(Chemistry, Physical)Neutron diffraction patterns for deuterated poly-
,,-dimethylacrylamide (PDMAA) hydrogels were measured from 10 to 300 K to investigate the structure and properties of water in the gels. Diffraction peaks observed below 250 K indicate the existence of ice in the hydrogels. Some diffraction peaks from the ice are at lower diffraction angles than those in ordinary hexagonal ice (Ih). These shifts in peaks indicate that the lattice constants of the 
and 
axes in the ice are about 0.29% and 0.3% higher than those in ice Ih, respectively. The results show that bulk low-density ice can exist in PDMAA hydrogels. The distortions in the lattice structure of ice imply significant interactions between water molecules and the surrounding polymer chains, which play an important role in the chemical and mechanical properties of the hydrogel.
Ru
)
Sb
investigated by inelastic X-ray scatteringTsutsui, Satoshi; Kaneko, Koji; Miyazaki, Ryoichi*; Higashinaka, Ryuji*; Aoki, Yuji*; Kobayashi, Riki*; Wakimoto, Shuichi; Baron, A. Q. R.*; Sugawara, Hitoshi*; Sato, Hideyuki*
JPS Conference Proceedings (Internet), 3, p.011060_1 - 011060_5, 2014/06
Kobayashi, Riki; Kaneko, Koji; Wakimoto, Shuichi; Chi, S.*; Sanada, Naoyuki*; Watanuki, Ryuta*; Suzuki, Kazuya*
Journal of the Korean Physical Society, 63(3), p.337 - 340, 2013/08
Times Cited Count：4 Percentile：33.49(Physics, Multidisciplinary)
Al (
= Ru and Os); Single crystal neutron diffraction studiesKato, Harukazu*; Kobayashi, Riki; Takesaka, Tomoaki*; Nishioka, Takashi*; Matsumura, Masahiro*; Kaneko, Koji; Metoki, Naoto
Journal of the Physical Society of Japan, 80(7), p.073701_1 - 073701_4, 2011/07
Times Cited Count：61 Percentile：89.28(Physics, Multidisciplinary)AlKobayashi, Riki; Kawamura, Yukihiro*; Nishioka, Takashi*; Kato, Harukazu*; Matsumura, Masahiro*; Matsubayashi, Kazuyuki*; Uwatoko, Yoshiya*; Kaneko, Koji
no journal, ,
no abstracts in English
Al, 3Kobayashi, Riki; Kaneko, Koji; Wakimoto, Shuichi; Haga, Yoshinori; Matsuda, Tatsuma; Yamamoto, Etsuji; Robert, J.*; Mignot, J.-M.*; Andr, G.*; Matsuda, Masaaki*; et al.
no journal, ,
no abstracts in English
(R=Tb, Ho)Kaneko, Koji; Wakimoto, Shuichi; Chi, S.*; Sanada, Naoyuki*; Watanuki, Ryuta*; Suzuki, Kazuya*; Kobayashi, Riki
no journal, ,
no abstracts in English
SbKaneko, Koji; Wakimoto, Shuichi; Kobayashi, Riki; Matsuda, Tatsuma; Tsutsui, Satoshi*; Chi, S.*; Kimura, Hiroyuki*; Noda, Yukio
no journal, ,
no abstracts in English
Al using Rh substitutionKobayashi, Riki; Kaneko, Koji; Wakimoto, Shuichi; Haga, Yoshinori; Matsuda, Tatsuma; Yamamoto, Etsuji; Robert, J.*; Mignot, J.-M.*; Andr, G.*; Matsuda, Masaaki*; et al.
no journal, ,
no abstracts in English
Sekine, Yurina; Fukazawa, Tomoko*; Kobayashi, Riki*; Chi, S.*; Fernandez, J.*; Fukazawa, Hiroshi
no journal, ,
Hydrogels are unique materials that can contain a large amount of water in their three-dimensional polymer chain networks. We used neutron diffraction to probe the structure of DO in poly-,,-dimethylacrylamide (PDMAA) hydrogel. Two PDMAA hydrogels with high and low DO-content W (W = 0.9 and 0.5) were prepared. The neutron diffraction measurements were performed using the Wide Angle Neutron Diffractometer (WAND) at the High Flux Isotope Reactor in Oak Ridge, U.S.A. The samples were rapidly cooled using liquid nitrogen, and then heated from 10 to 300 K. The neutron diffraction profiles of the high DO-content PDMAA gel (W = 0.9) have strong sharp peaks below 270 K that are similar to diffraction patterns of hexagonal ice Ih. At 300 K, the profile has a broad liquid-like diffraction feature. The profile of the gel at W = 0.5 has a broad band in the 2
range from 20
- 28 below 230 K that are similar to diffraction pattern of glassy water. Sharp peaks are observed in the profile at 230 K. The feature of the profile is similar to that of cubic ice. The profile at 260 K has ice Ih-like strong peaks. Our neutron diffraction results show the existence of ice in hydrogels and that the structure of ice depends on the water content of the hydrogel. The structural changes of ice in hydrogels might have important implications in the interpretation of hydrogel properties, for both biological tissues and synthetic gel materials.
CoGa (=Tb, Dy, Ho)Kobayashi, Riki; Kaneko, Koji; Wakimoto, Shuichi; Chi, S.*; Sanada, Naoyuki*; Watanuki, Ryuta*; Suzuki, Kazuya*
no journal, ,
no abstracts in English
AlKobayashi, Riki; Kawamura, Yukihiro*; Hirai, Daishi*; Nishioka, Takashi*; Kato, Harukazu*; Matsumura, Masahiro*; Matsubayashi, Kazuyuki*; Uwatoko, Yoshiya*; Kaneko, Koji
no journal, ,
no abstracts in English
