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Tanaka, Nobuyuki; Sawada, Shinichi*; Sugimoto, Chihiro; Yamaki, Tetsuya*
no journal, ,
We have been developing the ion exchange membranes by a radiation grafted polymerization method to improve HI concentration performance for Electro-electrodialysis (EED) in the thermochemical water-splitting hydrogen production iodine-sulfur process. We verify to adopt the cation exchange membrane prepared by ion-track grafted technique. In this membrane preparation technique, one-dimensional cylindrical ion-channel can be formed in the base polymer film by the radiation of the heavy ion beam. And, the excess swelling of the ion-channel could be prevented, expecting that the HI concentration performance could be improved. In our works, The HI concentration experiment was conducted by the electric cell assembled the membrane prepared by the ion-track grafting technique. The HI composition of the tested solution increased, indicating that the tested membrane can operate HI concentration by EED.
Tsuru, Tomohito; Shimizu, Kazuyuki*; Yamaguchi, Masatake; Itakura, Mitsuhiro; Ebihara, Kenichi; Bendo, A.*; Matsuda, Kenji*; Toda, Hiroyuki*
no journal, ,
Age-hardening has been one and only process to achieve high strength aluminum alloys since unlike iron and titanium, pure aluminum does not have other solid phases during heat treatment. Highly-concentrated precipitations play therefore dominant role in mechanical properties and hydrogen embrittlement of aluminum alloys. It has been considered that the coherent interface between matrix and precipitation does not contribute to the crack initiation and embrittlement due to its coherency. Here, we discovered the origin of unprecedented quasi-cleavage fracture mode. Hydrogen partitioning at various defect sites is investigated comprehensively combined with experiment, theory and first-principles calculations. We demonstrate that despite low excess free volume, the aluminum-precipitation interface is more preferable trap site than void and grain boundary. The cohesivity of the interface deteriorates significantly with increasing occupancy while hydrogen atoms are trapped stably up to extremely high occupancy equivalent to spontaneous cleavage.
Lobzenko, I.; Tsuru, Tomohito
no journal, ,
irradiated with swift heavy ions at grazing incidenceIshikawa, Norito; Fujimura, Yuki; Kondo, Keietsu; Szabo, G. L.*; Wilhelm, R. A.*; Ogawa, Hiroaki
no journal, ,
Surface nanostructure of Nb-doped SrTiO irradiated with swift heavy ions at grazing incidence was investigated by AFM (atomic force microscopy) and SEM (scanning electron microscopy). AFM picture and SEM picture show different appearance. Based on the new SEM results, mechanism of surface nanostructure formation is discussed.
Thomsen, B.; Shiga, Motoyuki
no journal, ,
Yamaguchi, Masatake; Tsuru, Tomohito; Ebihara, Kenichi; Itakura, Mitsuhiro
no journal, ,
The interface between precipitates and aluminum lattice in aluminum alloys is often an incommensurate interface due to lattice mismatch. Since first-principles calculations can only handle small periodic boundary cell atomic models, it is generally believed that incommensurate interfaces cannot be calculated. However, the recent development of computers has made it possible to handle up to 1000 atoms, and the hydrogen trapping energy can be calculated with sufficient accuracy by handling about 100 metal atoms around a hydrogen atom. In the present study, the hydrogen trapping energy at the incommensurate interface between MgZn
precipitates (or MgSi particles) and the aluminum matrix was calculated from first principles.
SR as a potential tool for depth-resolved detection of oxygen vacancies in perovskite oxidesIto, Takashi; Higemoto, Wataru; Koda, Akihiro*; Shimomura, Koichiro*
no journal, ,
Ito, Kanae; Yamada, Takeshi*; Shinohara, Akihiro*; Takata, Shinichi; Kawakita, Yukinobu
no journal, ,