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Fukaya, Yuki; Mochizuki, Izumi*; Maekawa, Masaki; Wada, Ken*; Hyodo, Toshio*; Matsuda, Iwao*; Kawasuso, Atsuo
no journal, ,
no abstracts in English
(110) surfacesMochizuki, Izumi*; Ariga, Hiroko*; Fukaya, Yuki; Wada, Ken*; Asakura, Kiyotaka*; Maekawa, Masaki; Kawasuso, Atsuo; Shidara, Tetsuo*; Hyodo, Toshio*
no journal, ,
no abstracts in English
Hyodo, Toshio*; Fukaya, Yuki; Mochizuki, Izumi*; Maekawa, Masaki; Wada, Ken*; Shidara, Tetsuo*; Ichimiya, Ayahiko*; Kawasuso, Atsuo
no journal, ,
no abstracts in English
Wada, Ken*; Maekawa, Masaki; Fukaya, Yuki; Mochizuki, Izumi*; Hyodo, Toshio*; Shidara, Tetsuo*; Kawasuso, Atsuo
no journal, ,
no abstracts in English
Machida, Akihiko; Higuchi, Kensuke*; Katayama, Yoshinori; Sakaki, Koji*; Kim, H.*; Nakamura, Yumiko*
no journal, ,
To improve performance of hydrogen storage materials, it is essential to understand detailed mechanism of hydrogenation and dehydrogenation reactions. In-situ powder diffraction measurements provide direct information about structural changes accompanying the reactions. We therefore installed a time-resolved X-ray diffraction (XRD) system at a beamline BL22XU at the SPrign-8, a synchrotron radiation facility in Japan. The system equipped area detectors. A sample cell was connected to a hydrogen supply system. The pressure of hydrogen gas was limited to 1 MPa. To demonstrate the performance of the system, we have performed time-resolved XRD experiments for LaNi
Al
. LaNi
exhibits the significant broadening of the diffraction peaks by hydrogen absorption; however, LaNiAl shows the no significant broadening. We have succeeded in the measurements of the structural change from the solid solution phase to the hydride phase and have found the formation of the transient intermediate phase on this reaction process. The system is currently used to study several materials.
Ohara, Takashi; Kiyanagi, Ryoji; Kaneko, Koji; Kawasaki, Takuro; Oikawa, Kenichi; Tamura, Itaru; Nakao, Akiko*; Hanashima, Takayasu*; Munakata, Koji*; Moyoshi, Taketo*
no journal, ,
H(SeO
)Kiyanagi, Ryoji; Matsuo, Yasumitsu*; Ishikawa, Yoshihisa*; Noda, Yukio*; Ohara, Takashi; Kawasaki, Takuro; Oikawa, Kenichi; Kaneko, Koji; Tamura, Itaru; Hanashima, Takayasu*; et al.
no journal, ,
The materials represented as MH(XO) (M=alkali metals, X=Se, S) are known to exhibit high protonic conductivities at relatively low temperature. Although the high protonic conductivity is considered to be due to the disorder of the hydrogen bonds in the materials, details have not been well understood. In addition, clarification of the phase transition to the high proton conducting phase is important in order to understand the realization of the high protonic conductivity. In this study, a high temperature neutron structural study was carried out on RbH(SeO), and the solid solution of Rb
K
H(SeO) were also investigated by means of conductivity measurements and neutron structural studies. The high temperature neutron structure analyses revealed that the protons in the high proton conducting phase were two dimensionally distributed, which is considered to be the direct observation of the conducting protons. The solid solution exhibited non-linear decreases of the phase transition temperatures as the K concentration increased. The K ions were found to prefer to occupy one of two possible sites, of which occupancies apparently have close relationship with the phase transition temperature.
Tamada, Taro; Kinoshita, Takayoshi*; Kurihara, Kazuo; Tada, Toshiji*; Kuroki, Ryota
no journal, ,
Elastase is a serine protease classified in the chymotrypsin family, and is attractive target for studies of structure based drug design (SBDD). The structural information including hydrogen positions and hydration will help us to further elucidate the catalytic mechanism of serine protease. To obtain such structural information, we performed the neutron structure analyses of porcine pancreatic elastase (PPE) with and without its inhibitor using diffraction data obtained at a BIX-3 diffractometer in the research reactor JRR-3. The PPE structure in complex with/without peptidic inhibitor, which was used to mimic the tetrahedral intermediate state, was determined to 1.65/1.90 
resolution, respectively. This structural information allows us to understand the role of resting state upon the catalytic reaction. Furthermore, the structural change of the active site residues including hydration structure obtained from the comparison between structures with and without inhibitor may help designing potent inhibitors by SBDD.
Kurihara, Kazuo; Tomoyori, Katsuaki; Tamada, Taro; Kuroki, Ryota
no journal, ,
Many proteins, especially membrane proteins and protein complexes, have larger molecular weight and then unit cells of their crystals have larger volume. Therefore, our group had designed the diffractometer which can cover such crystals with large unit cell volume (target lattice length: 250 ) at J-PARC. In order to separate spots closer to each other in spatial as well as time dimension in diffraction images, our proposed diffractometer adopts longer camera distance (L2 = 800 mm) and selects decoupled hydrogen moderator as neutron source which has shorter pulse width. Under the conditions that L1 is 33.5 m, beam divergence 0.4 deg and crystal edge size 2 mm, this diffractometer is estimated to be able to resolves spots diffracted from crystals with a lattice length of 220 in each axis at d-space of 2.0 . In order to cover large neutron detecting area due to long camera distance, novel large-area detector (larger than 300 mm 
300 mm) with a spatial resolution of better than 2.5 mm is under development. The final gain factor of this diffractometer is estimated to be about 20 or larger as compared with BIX-3/4 diffractometers operated in the research reactor JRR-3 at JAEA.
Hirano, Yu; Takeda, Kazuki*; Kurihara, Kazuo; Tamada, Taro; Miki, Kunio*
no journal, ,
It is important for understanding the electron transfer reaction to include the information about valence shell electrons and hydrogen atoms into crystal structure refinement. Recently, we have successfully collected 0.48 resolution data of high-potential iron-sulfur protein (HiPIP) in BL41XU beamline of SPring-8. We performed multipolar refinement with the 
program to consider valence shell electrons in the structure refinement of HiPIP. After multipolar refinement, the deformation map clearly displays the distribution of valence shell electrons such as lone-pair electrons of carbonyl oxygen atoms, bonding electrons in aromatic rings, and 
-orbital electrons of Fe atoms in the FeS cluster. In addition, we performed preliminary neutron diffraction experiment at iBIX beamline of Japan Proton Accelerator Research Complex (J-PARC) and observed diffraction spots up to 1.17 resolution using HiPIP crystal with the size of 2.3 mm
.
Watanuki, Tetsu; Yamada, Tsunetomo*; Nakamura, Yoko*; Tanaka, Yukinori*; Machida, Akihiko; Tsai, A. P.*; Ishimasa, Tsutomu*
no journal, ,
no abstracts in English