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Journal Articles

Hydroxyl group/fluorine disorder in deuterated magnesium hydroxyfluoride and behaviors of hydrogen bonds under high pressure

He, X.*; Kagi, Hiroyuki*; Komatsu, Kazuki*; Iizuka, Riko*; Okajima, Hajime*; Hattori, Takanori; Sano, Asami; Machida, Shinichi*; Abe, Jun*; Goto, Hirotada*; et al.

Journal of Molecular Structure, 1310, p.138271_1 - 138271_8, 2024/08

High-pressure responses of the O-D$$cdotcdotcdot$$F hydrogen bonds in deuterated magnesium hydroxyfluoride were investigated using neutron powder diffraction and Raman spectroscopy. The Rietveld analysis at ambient conditions revealed a chemical formula of Mg(OD)$$_{0.920(12)}$$F$$_{1.080(12)}$$ and hydroxyl group/fluorine disorder (OD/F disorder) in the crystal structure, which gave rise to two hydrogen-bonding configurations. The Rietveld analysis showed the hydrogen-bonding geometries remains up to 9.8 GPa, indicating no pressure-induced strengthening of hydrogen bonds. The Raman spectra at ambient conditions showed three hydroxyl stretching bands at 2613, 2694, and 2718 cm$$^{-1}$$. The high frequencies of the O-D stretching modes indicated that the hydroxyls should be involved in weak or none hydrogen-bonding interactions. Up to 20.2 GPa, the mode initially centered at 2694 cm$$^{-1}$$ displayed a pressure-induced blue shift, revealing no strengthening of hydrogen bonds under compression. We discuss the existence of hydrogen bonds and the causes of the blue-shifting hydroxyls at ambient and at high pressures.

Journal Articles

Deuterated malonamide synthesis for fundamental research on solvent extraction systems

Micheau, C.; Ueda, Yuki; Akutsu, Kazuhiro*; Bourgeois, D.*; Motokawa, Ryuhei

Solvent Extraction and Ion Exchange, 41(2), p.221 - 240, 2023/02

 Times Cited Count:1 Percentile:51.1(Chemistry, Multidisciplinary)

Journal Articles

Positron annihilation study of tungsten exposed to low-energy deuterium plasma

Hirade, Tetsuya; Furuta, Hikaru*; Torikai, Yuji*; Fujimura, Yuki; Michishio, Koji*

JJAP Conference Proceedings (Internet), 9, p.011106_1 - 011106_7, 2023/00

Positron annihilation lifetime (PAL) measurements by use of a positron source of $$^{22}$$Na were performed for polycrystalline ITER-grade tungsten samples exposed to low-energy deuterium plasma. The energy of deuterium plasma was low and then it was expected that it would affect just near-surface region. However, we obtained the longer mean positron annihilation lifetime in the tungsten samples exposed to the low-energy deuterium plasma than the virgin tungsten samples. Moreover, almost same longer values were obtained even on the other (no exposed) side of the samples, although the thickness of the samples were about 2 mm. Although, there has been no report of observation of defect formation by existence of hydrogen or deuterium in tungsten, the results indicated that deuterium existence in tungsten can be one of reasons of defects formation.

Journal Articles

Determination of localized surface phonons in nanocrystalline silicon by inelastic neutron scattering spectroscopy and its application to deuterium isotope enrichment

Matsumoto, Takahiro*; Nomata, Ikumi*; Ohara, Takashi; Kanemitsu, Yoshihiko*

Physical Review Materials (Internet), 5(6), p.066003_1 - 066003_9, 2021/06

 Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)

JAEA Reports

Tritium removal of heavy water system and helium system in FUGEN

Takiya, Hiroaki; Kadowaki, Haruhiko; Matsushima, Akira; Matsuo, Hidehiko; Ishiyama, Masahiro; Aratani, Kenta; Tezuka, Masashi

JAEA-Technology 2020-001, 76 Pages, 2020/05

JAEA-Technology-2020-001.pdf:6.06MB

Advanced Thermal Reactor (ATR) FUGEN was operated for about 25 years, and now has been proceeding decommissioning after the approval of the decommissioning plan in Feb. 2008. The reactor, heavy water system and helium system are contaminated by tritium because of neutron absorption of heavy water, which is a moderator. Before dismantling these facilities, it is necessary to remove tritium from them for not only reducing the amount of tritium released to surrounding environment and the risk of internal exposure by tritium but also ensuring the workability. In first phase of decommissioning (Heavy Water and Other system Decontamination Period), tritium decontamination of the reactor, heavy water system and helium system started in 2008 and completed in 2018. This report shows the results of tritium decontamination of the reactor, heavy water system and helium system.

Journal Articles

Diffusion behavior of D$$_{2}$$O in Fe$$_{3}$$O$$_{4}$$ film on Fe formed in an NaOH solution containing oxidants

Haruna, Takumi*; Miyataki, Yuki*; Hirohata, Yohei*; Shibata, Toshio*; Taniguchi, Naoki; Tachikawa, Hirokazu*

Zairyo To Kankyo, 67(9), p.375 - 380, 2018/09

This research aimed to confirm the formation of Fe$$_{3}$$O$$_{4}$$ film on Fe immersed in aqueous 45 mass% NaOH solution containing some oxidants at the boiling temperature, to recognize the optimum immersion time for the formation of thick and protective film, and to reveal the absorption behavior of D$$_{2}$$O in the Fe$$_{3}$$O$$_{4}$$ film at room temperature. The results were obtained as follows. It was confirmed that Fe$$_{3}$$O$$_{4}$$ film was formed on Fe immersed in the NaOH solution for a time more than 0.6 ks, and the film thickness increased parabolically with an increase in the immersion time. D$$_{2}$$O absorption test was carried out to the films formed in the NaOH solution for immersion times of 1.2 and 3.6 ks. An amount of D$$_{2}$$O absorbed into the film increased with an increase in an absorption time up to 1000 ks, and an absorption time more than 1000 ks made an amount of D$$_{2}$$O constant. The constant amount of D$$_{2}$$O was larger for the film formed on Fe immersed in the NaOH solution for 3.6 ks than that for 1.2 ks. The transient of the amount of D$$_{2}$$O absorbed into the film was analyzed on the basis of Fick's law for diffusion, and diffusion coefficients of D$$_{2}$$O were obtained to be 5.1$$times$$10$$^{-15}$$ cm$$^{2}$$ s$$^{-1}$$ and 9.9$$times$$10$$^{-15}$$ cm$$^{2}$$ s$$^{-1}$$ for the films formed for 1.2 and 3.6 ks, respectively. Therefore it was estimated that the diffusion coefficient of the Fe$$_{3}$$O$$_{4}$$ film was in the region from 5.1$$times$$10$$^{-15}$$ cm$$^{2}$$ s$$^{-1}$$ to 9.9$$times$$10$$^{-15}$$ cm$$^{2}$$ s$$^{-1}$$.

JAEA Reports

Deuterated Materials Enhancing Neutron Science for Structure Function Applications; October 19th-20th, 2017, Ibaraki Quantum Beam Research Center

Akutsu, Kazuhiro*; Adachi, Motoyasu*; Kawakita, Yukinobu

JAEA-Review 2018-002, 36 Pages, 2018/03

JAEA-Review-2018-002.pdf:4.67MB

Since J-PARC started operation for user programs with high-intensity pulsed neutron beams, many material and life science studies have been carried out at J-PARC. Since partial or complete deuteration of organic compounds for contrast variation in the scattering length densities of materials is one of the most effective techniques in the application of neutron scattering analysis, deuterated materials have led to significant progress in our understanding of the structure of novel organic materials. Aiming at accelerating development of deuteration activities in our country, an international workshop "Deuterated Materials Enhancing Neutron Science for Structure Function Applications" was held as a J-PARC Workshop at Ibaraki Quantum Beam Research Center from 19th October to 20th October in 2017. In this workshop, the chemical/biological deuteration activities and recent scientific results of deuterated materials enhancing neutron study in Japan and other countries were discussed by domestic/foreign deuteration and neutron scientists. This is a report of the workshop summarized by organizers.

Journal Articles

Tritium decontamination of contaminated system with tritiated heavy water by drying treatment

Kadowaki, Haruhiko; Matsushima, Akira; Nakajima, Yoshiaki

Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 6 Pages, 2016/06

Advanced thermal reactor "FUGEN" is a heavy water-moderated boiling light water-cooled pressure tube-type reactor. Because tritium had been generated in the heavy water during the reactor operation, the heavy water system and helium system were contaminated by tritium. The chemical form of the tritium was water molecule in FUGEN. Air-through drying and vacuum drying were applied to the system drying, and it was demonstrated that both methods were effective for drying treatment of heavy water in system. Helium system, low-contamination and non inclusion, could finish the vacuum drying rapidly. However, Heavy water purification system needed long period for drying treatment. The result showed that it needed long period to dry up if the objects include the adsorbent of water such as alumina pellet, resin and silica gel. But it can be accelerated by replacement absorbed heavy water to light water from the result of drying treatment of the rotary type dehumidifier.

Journal Articles

A Design study for tritium recovery system from cooling water of a fusion power plant

Yamanishi, Toshihiko; Iwai, Yasunori; Kawamura, Yoshinori; Nishi, Masataka

Fusion Engineering and Design, 81(1-7), p.797 - 802, 2006/02

 Times Cited Count:9 Percentile:53.38(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Selective OD bond dissociation of HOD; Photodissociation of vibrationally excited HOD in the 5$$nu$$$$_{OD}$$ state

Akagi, Hiroshi; Fukazawa, Hiroshi; Yokoyama, Keiichi; Yokoyama, Atsushi

Journal of Chemical Physics, 123(18), p.184305_1 - 184305_7, 2005/11

 Times Cited Count:21 Percentile:57.25(Chemistry, Physical)

Vibrationally excited HOD in the fourth overtone state of the OD-stretching mode (5$$nu$$$$_{OD}$$) has been photodissociated by ultraviolet photolysis at ca. 243.1 nm. Branching ratio between the OH- and OD-bond dissociation channels has been determined by detecting the H and D atoms. The OD-bond dissociation is the dominant channel, with the yield of H atom generated by the photolysis being below the detection limit.

Journal Articles

Comparison of tritium retention and carbon deposition in JET and JT-60U

Tanabe, Tetsuo*; Sugiyama, Kazuyoshi*; Coad, P.*; Bekris, N.*; Glugla, M.*; Miya, Naoyuki

Journal of Nuclear Materials, 345(2-3), p.89 - 95, 2005/10

 Times Cited Count:17 Percentile:73.49(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Gas release of SiC implanted with deuterium or helium

Aihara, Jun; Sawa, Kazuhiro; Furuya, Yoshio*; Hojo, Tomohiro*; Furuno, Shigemi*; Yamamoto, Hiroyuki; Hojo, Kiichi; Ishihara, Masahiro

Journal of the American Ceramic Society, 88(8), p.2319 - 2321, 2005/08

 Times Cited Count:0 Percentile:0.02(Materials Science, Ceramics)

no abstracts in English

Journal Articles

Local bonding states of ion-irradiated graphite characterized by photon-stimulated desorption (PSD) spectroscopy

Sekiguchi, Tetsuhiro; Baba, Yuji; Shimoyama, Iwao; Nath, K. G.

Journal of Electron Spectroscopy and Related Phenomena, 144-147, p.437 - 441, 2005/06

 Times Cited Count:3 Percentile:17.62(Spectroscopy)

no abstracts in English

JAEA Reports

JRR-2 decommissioning activity, 2

Suzuki, Takeshi; Nakano, Masahiro; Okawa, Hiroshi; Terunuma, Akihiro; Kishimoto, Katsumi; Yano, Masaaki

JAERI-Tech 2005-018, 84 Pages, 2005/03

JAERI-Tech-2005-018.pdf:27.52MB

no abstracts in English

Journal Articles

Exhaust gas monitoring device of nuclear fusion experimental device

Kaminaga, Atsushi; Nakamura, Hirofumi; Isobe, Kanetsugu; Arai, Takashi

Heisei-16-Nendo Osaka Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 4 Pages, 2005/03

no abstracts in English

Journal Articles

Retention characteristics of hydrogen isotopes in JT-60U

Masaki, Kei; Sugiyama, Kazuyoshi*; Hayashi, Takao; Ochiai, Kentaro; Goto, Yoshitaka*; Shibahara, Takahiro*; Hirohata, Yuko*; Oya, Yasuhisa*; Miya, Naoyuki; Tanabe, Tetsuo*

Journal of Nuclear Materials, 337-339, p.553 - 559, 2005/03

 Times Cited Count:26 Percentile:84.04(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Isotope hydrograph separation for modeling of runoff mechanisms of atmospherically derived chemical and radioactive pollutants

Matsunaga, Takeshi; Yanase, Nobuyuki; Hanzawa, Yukiko; Tsuzuki, Katsunori; Naganawa, Hirochika

Journal of Water and Environment Technology (Internet), 3(2), p.243 - 252, 2005/00

In a tributary watershed of the Kuji River of Japan, the hydrological components of runoff associated with a rain storm event were investigated using isotope tracers of hydrogen ($$^{2}$$H) and oxygen ($$^{18}$$O) in precipitations and stream water. The runoff was separated into either "old water" (pre-existing in the ground before the storm) and "new water"(from the storm precipitation). It was found that the discharge of several hazardous trace elements (Sb, Cu, Cr) was largely (24-54%) attributable to that of the new water in spite of its small contribution to the total water discharge. These investigations suggest that the new water may play an important role in the migration of atmospherically derived, hazardous trace elements to streams during rain storms.

Journal Articles

Energetic neutral particle measurement with natural diamond detector in JT-60U

Kusama, Yoshinori; Ishikawa, Masao; Takechi, Manabu; Nishitani, Takeo; Morioka, Atsuhiko; Sasao, Mamiko*; Isobe, Mitsutaka*; Krasilnikov, A.*; Kaschuck, Y.*

Proceedings of Plasma Science Symposium 2005/22nd Symposium on Plasma Processing (PSS-2005/SPP-22), p.395 - 396, 2005/00

The energetic neutral particles have been successfully measured with a natural diamond detector in the neutron and $$gamma$$ ray radiation circumstance of the JT-60U deuterium discharges. The diamond detector was covered with polyethylene and lead in order to reduce the neutron and $$gamma$$ ray background. The shield has shown expected shielding capability. A rapid increase in neutral particles has been observed at the onset of the Toroidal Alfven Eigenmode (TAE) excited by the negative-ion-based neutral beam injection. The energy range of increased neutral particles has agreed well with that predicted from the resonant interaction between the energetic ions and the TAE.

Journal Articles

Present status of JRR-2 decommissioning

Nakano, Masahiro; Okawa, Hiroshi; Suzuki, Takeshi; Kishimoto, Katsumi; Terunuma, Akihiro; Yano, Masaaki

Dekomisshoningu Giho, (30), p.11 - 24, 2004/09

Japan Research Reactor No.2(JRR-2), heavy water moderated and cooled tank type research reactor with maximum thermal power of 10MW,was operated for over 36 years, and was permanently shut down in December, 1996. In 1997, decommissioning plan was submitted to the STA, and dismantling was begun. Decommissioning program of JRR-2 is divided into 4 phases. Phase 1, 2 had already been completely finished without any trouble. Furthermore, the phase 3 was also finished in February, 2004 as planned. On exposure of worker in phase 1, 2 and 3, it was achieved to control lower than the estimate. On exposure of worker in phase 1, 2 and 3, it was achieved to control lower than the estimate. Reactor will be removed in phase 4 by one piece removal technique. The reactor building is planned to use effectively as a hot experimental facilities after decommissioning. The decommissioning plan was changed that the reactor would be kept in safety storage.

Journal Articles

Conformational changes of troponin C within the thin filaments detected by neutron scattering

Matsumoto, Fumiko*; Makino, Koji*; Maeda, Kayo*; Patzelt, H.*; Maeda, Yuichiro*; Fujiwara, Satoru

Journal of Molecular Biology, 342(4), p.1209 - 1221, 2004/09

 Times Cited Count:19 Percentile:29.79(Biochemistry & Molecular Biology)

Regulation of skeletal and cardiac muscle contraction is associated with the thin filament-based proteins, troponin C (TnC), TnI, TnT, tropomyosin, and actin. Knowledge of ${it in situ}$ structures of these proteins is indispensable for elucidating the molecular mechanism of this Ca$$^{2+}$$-sensitive regulation. Here the structure of TnC within the thin filaments was investigated with neutron scattering, combined with selective deuteration and the contrast matching technique. Deuterated TnC was prepared, reconstituted into the native thin filaments, and neutron scattering patterns of these reconstituted thin filaments containing deuterated TnC were measured under the condition where non-deuterated components were rendered 'invisible' to neutrons. The obtained scattering curves arising only from deuterated TnC were analyzed by model calculations using the Monte Carlo method. The results showed that upon binding of Ca$$^{2+}$$, ${it in situ}$ radius of gyration of TnC changed from 23 AA to 24 AA , and the radial position of TnC within the thin filament changed from 53 AA to 49 AA .

225 (Records 1-20 displayed on this page)