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Unno, Masayoshi*; Ishikawa, Kumiko*; Kusaka, Katsuhiro*; Tamada, Taro; Hagiwara, Yoshinori*; Sugishima, Masakazu*; Wada, Kei*; Yamada, Taro*; Tomoyori, Katsuaki; Hosoya, Takaaki*; et al.
Journal of the American Chemical Society, 137(16), p.5452 - 5460, 2015/04
Times Cited Count：28 Percentile：64.39(Chemistry, Multidisciplinary)Phycocyanobilin, a light-harvesting and photoreceptor pigment in higher plants, algae, and cyanobacteria, is synthesized from biliverdin IX
(BV) by phycocyanobilin:ferredoxin oxidoreductase (PcyA) via two steps of two-proton-coupled two-electron reduction. We determined the neutron structure of PcyA from cyanobacteria complexed with BV, revealing the exact location of the hydrogen atoms involved in catalysis. Notably, approximately half of the BV bound to PcyA was BVH
, a state in which all four pyrrole nitrogen atoms were protonated. The protonation states of BV complemented the protonation of adjacent Asp105. The "axial "water molecule that interacts with the neutral pyrrole nitrogen of the A-ring was identified. His88 N
was protonated to form a hydrogen bond with the lactam O atom of the BV A-ring. His88 and His74 were linked by hydrogen bonds via H
O. These results imply that Asp105, His88, and the axial water molecule contribute to proton transfer during PcyA catalysis.
Sonoda, Tetsu*; Wada, Michiharu*; Tomita, Hideki*; Sakamoto, Chika*; Takatsuka, Takaaki*; Furukawa, Takeshi*; Iimura, Hideki; Ito, Yuta*; Kubo, Toshiyuki*; Matsuo, Yukari*; et al.
Nuclear Instruments and Methods in Physics Research B, 295, p.1 - 10, 2013/01
Times Cited Count：21 Percentile：83.85(Instruments & Instrumentation)no abstracts in English
Fukumoto, Masakatsu; Nakano, Tomohide; Itami, Kiyoshi; Wada, Takaaki*; Ueda, Yoshio*; Tanabe, Tetsuo*
Journal of Nuclear Materials, 415(Suppl.1), p.S705 - S708, 2011/08
Times Cited Count：5 Percentile：38.65(Materials Science, Multidisciplinary)Tungsten coating on the first wall in ITER is proposed to reduce in-vessel tritium retention. However, it is possibility that carbon based materials would be used at high heat load components such as limiter. To predict the tritium retention in tungsten coating, it is essential to investigate the effects of carbon impurity on deuterium retention in tungsten coating. In this study, effects of carbon impurity on deuterium retention in the tungsten coating exposed to JT-60U divertor plasmas were investigated. Deuterium was trapped by carbon which was implanted and accumulated in the tungsten coating during the plasma discharge. D/C ration of 0.04-0.08 in the tungsten coating was reached to 1/2-1/4 compared to T/C ration in carbon co-deposition layer. Therefore, simultaneous use of carbon armor materials and tungsten coating would enhance tritium retention in tungsten coating.
Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05
Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.
Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.
Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06
Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.
Sawamura, Masaru; Furuya, Takaaki*; Sakanaka, Shogo*; Suwada, Tsuyoshi*; Takahashi, Takeshi*; Umemori, Kensei*; Sakai, Hiroshi*; Shinoe, Kenji*
Proceedings of 2007 Particle Accelerator Conference (PAC '07) (Internet), p.1022 - 1024, 2007/06
An eccentric-fluted beam pipe was proposed to damp quadrupole modes. The eccentric-flute acts as a mode converter from quadrupole to dipole. Optimized parameters permit to damp both degenerate modes of quadrupole with the eccentric-flute. External Q-values measured with a low power model agreed well with those calculated with MAFIA.
Sakai, Hiroshi*; Shinoe, Kenji*; Furuya, Takaaki*; Sakanaka, Shogo*; Suwada, Tsuyoshi*; Takahashi, Takeshi*; Umemori, Kensei*; Sawamura, Masaru
Proceedings of 41st Advanced ICFA Beam Dynamics Workshop on Energy Recovery Linacs (ERL '07) (CD-ROM), p.56 - 61, 2007/05
For the energy recovery linacs (ERLs), strong higherorder-mode (HOM) damping is necessary to achieve high current operations. For this purpose, we have newly designed a 1.3 GHz 9-cell superconducting cavity. The cell shape of this cavity is designed and optimized for the high current ERL operation. The HOMs are extracted through the beam pipes and damped with RF absorbers. Furthermore, an idea of eccentric-fluted beam pipe (EFB) is proposed in order to extract the quadrupole HOMs. In this paper, strategy for the HOM suppression to optimise for the ERL operation and estimated HOM characteristics are described. Other important R&D items are also reported.
Umemori, Kensei*; Furuya, Takaaki*; Sakanaka, Shogo*; Suwada, Tsuyoshi*; Takahashi, Takeshi*; Sakai, Hiroshi*; Shinoe, Kenji*; Sawamura, Masaru
Proceedings of 4th Asian Particle Accelerator Conference (APAC 2007) (CD-ROM), p.570 - 572, 2007/01
no abstracts in English
Sawamura, Masaru; Umemori, Kensei*; Furuya, Takaaki*; Sakanaka, Shogo*; Takahashi, Takeshi*; Suwada, Tsuyoshi*; Sakai, Hiroshi*; Shinoe, Kenji*
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.472 - 474, 2007/00
An eccentric-fluted beam pipe has been proposed to damp quadrupole modes. The eccentric-flute acts as a mode converter from quadrupole to dipole. Optimized parameters permit to damp both degenerate modes of quadrupole with the eccentric-flute. External Q-values measured with a low power model agree well with those calculated with MAFIA.
Al conductorKoizumi, Norikiyo; Azuma, Katsunori*; Tsuchiya, Yoshinori; Matsui, Kunihiro; Takahashi, Yoshikazu; Nakajima, Hideo; Nishijima, Gen; Nunoya, Yoshihiko; Ando, Toshinari; Isono, Takaaki; et al.
Fusion Engineering and Design, 58-59, p.1 - 5, 2001/11
Times Cited Count：2 Percentile：19.66(Nuclear Science & Technology)no abstracts in English
Sugimoto, Makoto; Isono, Takaaki; Nunoya, Yoshihiko; Koizumi, Norikiyo; Nakajima, Hideo; Kato, Takashi; Matsukawa, Makoto; Hamada, Kazuya; Matsui, Kunihiro; Nishijima, Gen; et al.
IEEE Transactions on Applied Superconductivity, 10(1), p.564 - 567, 2000/03
Times Cited Count：22 Percentile：71.03(Engineering, Electrical & Electronic)no abstracts in English
Ando, Toshinari; Hiyama, Tadao; Takahashi, Yoshikazu; Nakajima, Hideo; Kato, Takashi; Isono, Takaaki; Sugimoto, Makoto; Kawano, Katsumi; Koizumi, Norikiyo; Nunoya, Yoshihiko; et al.
IEEE Transactions on Applied Superconductivity, 10(1), p.568 - 571, 2000/03
Times Cited Count：10 Percentile：53.54(Engineering, Electrical & Electronic)no abstracts in English
Ando, Toshinari; Hiyama, Tadao; Takahashi, Yoshikazu; Nakajima, Hideo; Kato, Takashi; Sugimoto, Makoto; Isono, Takaaki; Kawano, Katsumi; Koizumi, Norikiyo; Hamada, Kazuya; et al.
IEEE Transactions on Applied Superconductivity, 9(2), p.628 - 631, 1999/06
Times Cited Count：8 Percentile：51.51(Engineering, Electrical & Electronic)no abstracts in English
Sugimoto, Makoto; Isono, Takaaki; Koizumi, Norikiyo; Nakajima, Hideo; Kato, Takashi; Hamada, Kazuya; Nunoya, Yoshihiko; Matsui, Kunihiro; Sawada, Kenji*; Takahashi, Yoshikazu; et al.
IEEE Transactions on Applied Superconductivity, 9(2), p.636 - 639, 1999/06
Times Cited Count：1 Percentile：17.14(Engineering, Electrical & Electronic)no abstracts in English
Sawamura, Masaru; Umemori, Kensei*; Furuya, Takaaki*; Takahashi, Takeshi*; Sakanaka, Shogo*; Suwada, Tsuyoshi*; Sakai, Hiroshi*; Shinoe, Kenji*
no journal, ,
no abstracts in English
Sawamura, Masaru; Umemori, Kensei*; Furuya, Takaaki*; Takahashi, Takeshi*; Sakanaka, Shogo*; Suwada, Tsuyoshi*; Sakai, Hiroshi*; Shinoe, Kenji*
no journal, ,
no abstracts in English
Sakai, Hiroshi*; Shinoe, Kenji*; Umemori, Kensei*; Sakanaka, Shogo*; Suwada, Tsuyoshi*; Takahashi, Takeshi*; Furuya, Takaaki*; Sawamura, Masaru
no journal, ,
Development for energy-recovery linacs (ERLs) of the next generation light sources has begun in 2006. Superconducting cavities for the main linac is one of the essential technologies. The main linac has to accelerate and decelerate the high current beam of 100 mA stably. We present the design and development of the input couplers for the main linacs.
Umemori, Kensei*; Sakai, Hiroshi*; Sakanaka, Shogo*; Sawamura, Masaru; Shinoe, Kenji*; Suwada, Tsuyoshi*; Takahashi, Takeshi*; Furuya, Takaaki*
no journal, ,
We have been developing a 1.3-GHz superconducting cavity which is one of the essential components for energy-recovery linacs (ERLs). The ERL requires the accelerating gradient of 15-20 MV/m and CW beam operation of 100 mA. Damping of higher order modes is important for high current beam accelerators such as ERLs. We designed a new cavity of large iris diameter, ellipsoidal shape of equator and large beam pipe diameter to reduce the impedance of dipole modes. We also proposed eccentric-fluted beam pipe to damp quadrupole modes. The model cavities were manufactured and surface-treated. We report results of vertical measurement.
Sawamura, Masaru; Umemori, Kensei*; Sakanaka, Shogo*; Suwada, Tsuyoshi*; Takahashi, Takeshi*; Furuya, Takaaki*; Noguchi, Shuichi*; Kako, Eiji*; Shishido, Toshio*; Watanabe, Ken*; et al.
no journal, ,
Superconducting accelerator cavities are essential for the energy-recovery linac. The superconducting cavities are used in an injector and a main linac. A new model has been designed for the ERL. A center-single-cell cavity, an end-single-cell cavity and 9-cell cavity have been constructed. Vertical tests were performed for the center-single-cell cavity and the end-single cell cavity. A 2-cell cavity for the injector is under construction.
Fukumoto, Masakatsu; Nakano, Tomohide; Itami, Kiyoshi; Wada, Takaaki*; Ueda, Yoshio*; Tanabe, Tetsuo*
no journal, ,
no abstracts in English
