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Yoshii, Kenji; Ikeda, Naoshi*; Shimojo, Yutaka; Ishii, Yoshinobu*
Materials Chemistry and Physics, 190, p.96 - 101, 2017/04
Times Cited Count:15 Percentile:48.52(Materials Science, Multidisciplinary)Magnetic and dielectric properties have been studied for LaCrO, PrCrO, and their solid solution LaPrCrO, belonging to a family of ferroelectricorthochromite series CrO (: rare earths). The magnetic measurements confirm that the material shows canted antiferromagnetic ordering at 240-288 K. Neutron diffraction patterns could be fitted with the centrosymmetric , which is different from the non-centrosymmetric structure proposed for the ferroelectric phase of NdCrO. The large dielectric constants are likely due to the hopping of charge carriers as proposed previously for other chromites.
Esaka, Fumitaka; Yasuda, Kenichiro; Suzuki, Daisuke; Miyamoto, Yutaka; Magara, Masaaki
Talanta, 165, p.122 - 127, 2017/04
Times Cited Count:15 Percentile:52.34(Chemistry, Analytical)The isotope ratios of Pu/Pu, Pu/Pu, Pu/Pu, and Pu/Pu were measured for individual Pu and U-Pu mixed oxide particles by a combination of alpha spectrometry and inductively coupled plasma mass spectrometry (ICP-MS). As a consequence, we were able to determine the Pu/Pu, Pu/Pu, and Pu/Pu isotope ratios with ICP-MS after particle dissolution and chemical separation of uranium, plutonium and americium with UTEVA resins. Furthermore, Pu/Pu isotope ratios were able to be calculated by using both the Pu/(Pu+Pu) activity ratios that had been measured through alpha spectrometry and the Pu/Pu isotope ratios determined through ICP-MS. Therefore, the combined use of alpha spectrometry and ICP-MS is useful in determining plutonium isotope ratios, including Pu/Pu, in individual U-Pu mixed oxide particles.
Kataoka, Ryuho*; Sato, Tatsuhiko
Geoscience Frontiers, 8(2), p.247 - 252, 2017/03
Times Cited Count:5 Percentile:14.09(Geosciences, Multidisciplinary)Estimation of the depth-dose profile of ionization in protoplanetary disks by galactic cosmic rays (GCRs), solar protons, and by supernova remnants is of great importance in the analysis of planet formation. We therefore calculated the profile using Particle and Heavy Ion Transport code System PHITS. The attenuation length of GCR ionization is updated as 118 g cm, which is approximately 20% larger than the popular value. Hard and soft possible spectra of solar protons give 5% larger and 20% smaller attenuation lengths compared with those from standard GCR spectra, respectively. Further, all of the attenuation lengths become 10% larger in the compound gas of cosmic abundance, e.g. 128 g cm for GCRs, which can significantly affect the minimum estimate of the size of dead zones in protoplanetary disks.
Ueki, Taro
Journal of Nuclear Science and Technology, 54(3), p.267 - 279, 2017/03
Times Cited Count:8 Percentile:61.27(Nuclear Science & Technology)Analysis framework under material distribution uncertainty is investigated for the Monte Carlo (MC) criticality calculation of continuously mixed media formed via molten core concrete interaction. Deterministic trigonometric functions and randomized Weierstrass functions are utilized to represent the spatially continuous variation. Numerical results indicate that the effective multiplication factor (k) under random spatial variation can depart significantly from the k of a reference uniform medium. It is also shown that the deterministic modeling provides an upper-bound measure for extreme results from random realizations.
Irisawa, Keita; Meguro, Yoshihiro
Journal of Nuclear Science and Technology, 54(3), p.365 - 372, 2017/03
Times Cited Count:2 Percentile:19.65(Nuclear Science & Technology)Sasaki, Takayuki*; Kokami, Takayuki*; Kobayashi, Taishi*; Kirishima, Akira*; Murakami, Hiroaki; Amano, Yuki; Mizuno, Takashi; Iwatsuki, Teruki; Sasamoto, Hiroshi; Miyakawa, Kazuya
Journal of Nuclear Science and Technology, 54(3), p.373 - 381, 2017/03
Trace amounts of natural thorium and uranium in deep groundwater were investigated at two underground research laboratories situated at Horonobe and Mizunami, Japan. The groundwater was sampled from underground boreholes, and the colloid contribution was checked by in situ two size-fractionated ultrafiltration systems. A decrease in the concentration after in situ filtration suggested the presence of natural colloids and suspended matter that were carriers of a portion of the elements. The result of the Th and U concentrations in groundwater after 10 kDa filtration was analyzed thermodynamically using existing hydrogeological and geochemical data such as the mineral components in the groundwater at a given pH, ionic strength, concentration of co-existing ions, redox potential, and solid phase assumed. A crystalline solid phase made the solubility very low compared with that of the amorphous phase, and the solubility agreed well with the concentrations measured.
Ohashi, Yusuke; Tanaka, Yoshio; Tsunashima, Yasumichi; Ikeda, Yasuhisa*
Journal of Nuclear Science and Technology, 54(3), p.382 - 390, 2017/03
Times Cited Count:9 Percentile:61.27(Nuclear Science & Technology)Sludge-like uranium wastes (SUWs) have been generated with neutralization of acidic aqueous solutions used for decontamination of metal wastes containing a large amount of iron. We have examined the method for recovering uranium from such SUWs using -2-pyrrolidone (NCP) as a precipitate. As a result, it was found that precipitation ratios (PRs) of uranium in the solutions prepared by dissolving SUWs in HNO is 97.7% at [NCP]/[U(VI)] = 20, and that the PRs of iron, aluminum, fluorine, and sulfate species are less than 1%. This indicates that uranium species are precipitated selectively. The content ratios of U, Fe, Ca, F, and S in the materials after calcining precipitates obtained at [NCP]/[U(VI)] = 20 were in accordance with the conditions of uranium ore concentrate. From these results, it is expected that highly purified uranium can be efficiently recovered from SUWs by using NCP as the precipitant.
Sasaki, Koei; Fujimura, Ryota*; Tanigaki, Takanori; Matsubara, Masanori*; Fukumoto, Kenichi*; Uno, Masayoshi*
Journal of Nuclear Science and Technology, 54(2), p.139 - 146, 2017/02
Times Cited Count:6 Percentile:51.46(Nuclear Science & Technology)In an attempt to investigate Cs-Te corrosion depth dependence on distribution of chromium carbide precipitation in high chromium steel, Cs-Te corrosion out-pile tests of two 9Cr steels with different distributions of chromium carbide were carried out at 975K for 100h and their corrosion depths were compared. The corrosion is obviously more advanced in a specimen which has grain boundary carbide than in the one that does not. A considerable reason of the result is that the carbide distributed at grain boundaries promoted the corrosion reaction and the corrosion extended along the grain boundary. This is the first case in which the Cs-Te corrosion depth dependence on distribution of chromium carbide precipitation in Fe-Cr steel is clarified experimentally.
Yonezawa, Shingo*; Tajiri, Kengo*; Nakata, Suguru*; Nagai, Yuki; Wang, Z.*; Segawa, Koji*; Ando, Yoichi*; Maeno, Yoshiteru*
Nature Physics, 13(2), p.123 - 126, 2017/02
Times Cited Count:198 Percentile:99.01(Physics, Multidisciplinary)no abstracts in English
Seto, Hideki; Ito, Shinichi; Yokoo, Tetsuya*; Endo, Hitoshi*; Nakajima, Kenji; Shibata, Kaoru; Kajimoto, Ryoichi; Kawamura, Seiko; Nakamura, Mitsutaka; Kawakita, Yukinobu; et al.
Biochimica et Biophysica Acta; General Subjects, 1861(1), p.3651 - 3660, 2017/01
Times Cited Count:32 Percentile:80.67(Biochemistry & Molecular Biology)J-PARC, Japan Proton Accelerator Research Complex provides short pulse proton beam at a repetition rate 25 Hz and the maximum power is expected to be 1 MW. Materials and Life Science Experimental Facility (MLF) has 23 neutron beam ports and 21 instruments have already been operated or under construction / commissioning. There are 6 inelastic / quasi-elastic neutron scattering spectrometers and the complementary use of these spectrometers will open new insight for life science.
Yonezawa, Chushiro*; Shirono, Katsuhiro*; Haraga, Tomoko
Bunseki Kagaku, 66(1), p.27 - 37, 2017/01
Times Cited Count:0 Percentile:0(Chemistry, Analytical)no abstracts in English
Matsui, Hiroya; Mikake, Shinichiro; Ikeda, Koki; Sasaki, Sadao
Dai-14-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (Internet), 6 Pages, 2017/01
Japan Atomic Energy Agency (JAEA) has been conducting the groundwater recovery experiment to develop the methodology to estimate the recovery of geological environment after drift closure at GL-500m in Mizunami Underground Research Laboratory, Gifu prefecture, Japan. For the experiment, the impervious concrete plug was constructed to keep a recovered water pressure. The authors assessed the functions of the pluge based on monitoring and interpretation of the several kinds of measurements inside and outside of the plug during groundwater recovery process in a drift. As the results, the design concept and the expected function of the impervious plug assessed almost satisfied and it is supposed no problem will occur on the groundwater recovery experiment for several months.
Aoyagi, Kazuhei; Ishii, Eiichi
Dai-14-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (Internet), 6 Pages, 2017/01
The objective of this research is to investigate the hydro-mechanical properties of excavation damaged zones (EDZs) along the galleries excavated in 250 m and 350 m depths. We conducted hydraulic tests, BTV observations and core analyses. As a result, in the 250 m gallery, the extent of the EDZ was 1.0 m into the gallery wall. The hydraulic conductivity was increased by 2 to 3 orders of magnitudes compared with that of intact rock. On the other hand, in the 350 m gallery, the extent of the EDZ was 0.4 m into the gallery wall; the hydraulic conductivity was increased by 5 orders of magnitudes compared with that of intact rock. We investaged the difference of the characteristics of the EDZs on the basis of competence factor and ductility index. As a result, it was estimated that an extent of an EDZ decreases with decrease of competence factor; a hydraulic conductivity in an EDZ increases with decrease of ductility index.
Kamemura, Katsumi*; Aoyagi, Kazuhei; Nago, Makito*; Sugawara, Kentaro*; Matsubara, Makoto*
Dai-14-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (Internet), 6 Pages, 2017/01
In the design of deep underground structures such as high-level radioactive waste disposal repositories, the estimation of rock mass stress state is important as well as the estimation of mechanical characteristics of rock mass. This study establishes a practical and effective method for estimating in situ stress based on the convergence measurement results obtained during gallery construction of URL. The convergence was measured in various directions of the URL loop gallery at 350 m depth, and this will allow determination of the stress state over a large area using a back analysis method. In order to improve the accuracy of initial stress estimation, the relationship between convergence measurement results and geological situation of existing fractures were studied. The analysis results show good agreement with the in situ stress state results reported in previous studies and confirm the applicability of the proposed method.
Hata, Koji*; Niunoya, Sumio*; Aoyagi, Kazuhei
Dai-14-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (Internet), 6 Pages, 2017/01
The objective of this research is to investigate the long-term hydro-mechanical behavior of rock mass around the shaft in the Horonobe Underground Research Laboratory (URL). The long-term monitoring has been carried out by optical AE sensors, optical water pressure sensors, and optical temperature sensors below 350m depth of the shaft in the Horonobe URL. From the measurement results, the extent of an excavation damaged zone was 1.5m within the shaft wall. After the excavation, it was observed that the unsaturated zone of the groundwater was spread more than 1.5m within the shaft wall.
Nakashima, Hiroyoshi*; Koyama, Tomofumi*; Tatsuta, Keisuke*; Katayama, Tatsuo*; Aoyagi, Kazuhei
Dai-14-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (Internet), 6 Pages, 2017/01
In this study, we created the three dimensional model based on equivalent continuum approach to study the penetration length and enhancement of the hydraulic conductivity of the rock mass. The developed numerical model was applied to the in situ grout injection conducted in the ventilation shaft of the Horonobe Underground Research Laboratory. We evaluated the hydraulic conductivity of the rock mass after the grout operation. As a result, hydraulic conductivity of the highly permeable fault was decreased in 4 orders of magnitude, which is almost consistent with the in situ hydraulic conductivity obtained from in situ Luegeon test after the grout injection. Thus the simulation method described in this paper can be applied to the evaluation of the efficiency of in situ grout injection.
Kawashima, Koichiro*; Yano, Yasuhide; Tanno, Takashi; Kaito, Takeji
Dai-24-Kai Choompa Ni Yoru Hihakai Hyoka Shimpojiumu Koen Rombunshu (USB Flash Drive), p.99 - 104, 2017/01
no abstracts in English
Takaya, Shigeru; Chikazawa, Yoshitaka; Hayashida, Kiichi; Tagawa, Akihiro; Kubo, Shigenobu; Yamashita, Atsushi
Hozengaku, 15(4), p.71 - 78, 2017/01
A maintenance management suitable to nuclear power plants (NPP) at R&D stage was discussed. Objectives of maintenance management of NPP at R&D stage was first clarified. Next, applicability of codes for maintenance management of commercial NPP to NPP at R&D stage was discussed. Then, requirements and consideration for maintenance management of NPP at R&D stage was proposed. Finally, an example that the proposal was applied to setting maintenance program of sodium-cooled fast reactor was presented.
Abe, Shinichiro; Sato, Tatsuhiko
Journal of Nuclear Science and Technology, 54(1), p.101 - 110, 2017/01
Times Cited Count:9 Percentile:61.27(Nuclear Science & Technology)There are several researches for application of muons, e.g. the visualization of inner-structure of nuclear reactors by using high-energy cosmic-ray muons, nuclear transmutation of long-lived fission products (LLFPs) and nondestructive elemental analysis by using low-energy negative muon. In this study, we construct models for muon interactions (i.e., bremsstrahlung, electron-positron pair production, muon photonuclear interaction, and negative muon capture reaction) and implement them into PHITS in order to make PHITS available for investigations of muon application. The improved PHITS agrees well with experimental data not only for the vertical intensities of cosmic-ray muons in water and standard rock, but also for neutron production by muon photonuclear interaction and negative muon capture reaction. The improved PHITS can also reproduce the cross-section of radionuclide production by muons passing through a concrete wall very well. These results indicate the applicability of the improved PHITS to the shielding design of muon facilities in which estimations of attenuation length and induced radioactivity are important.
Mizuyama, Kazuhito; Iwamoto, Nobuyuki; Iwamoto, Osamu
Journal of Nuclear Science and Technology, 54(1), p.74 - 80, 2017/01
Tsuru, Tomohito
Materia, 56(1), p.5 - 13, 2017/01
Elements strategy becomes important to investigate alternative materials of rare metals. We have dedicated to establish a new approach based on computational methods. In the present paper, we propose two approaches based on first-principles and theory of dislocations. These methods are introduced to magnesium alloys.
Ungr, T.*; Harjo, S.; Kawasaki, Takuro; Tomota, Yo*; Ribrik, G.*; Shi, Z.*
Metallurgical and Materials Transactions A, 48(1), p.159 - 167, 2017/01
Times Cited Count:46 Percentile:90.37(Materials Science, Multidisciplinary)Iizuka, Riko*; Yagi, Takehiko*; Goto, Hirotada*; Okuchi, Takuo*; Hattori, Takanori; Sano, Asami
Nature Communications (Internet), 8, p.14096_1 - 14096_7, 2017/01
Times Cited Count:44 Percentile:88.82(Multidisciplinary Sciences)Density of the Earth's core is lower than that of pure iron and the light element(s) in the core is a long-standing problem. Hydrogen is the most abundant element in the solar system and thus one of the important candidates. However, the dissolution process of hydrogen into iron remained unclear. Here we carry out high-pressure and high-temperature in situ neutron diffraction experiments and clarify that when the mixture of iron and hydrous minerals are heated, iron is hydrogenized soon after the hydrous mineral is dehydrated. This implies that early in the Earth's evolution, as the accumulated primordial material became hotter, the dissolution of hydrogen into iron occurred before any other materials melted. This suggests that hydrogen is likely the first light element dissolved into iron during the Earth's evolution and it may affect the behaviour of the other light elements in the later processes.
Ueno, Akira
New Journal of Physics (Internet), 19(1), p.015004_1 - 015004_15, 2017/01
Times Cited Count:12 Percentile:64.28(Physics, Multidisciplinary)In order to satisfy the increasing intensity requirements of high-energy and high-intensity proton accelerators for an H ion beam with small transverse normalized rms emittances of around 0.25 mmmrad, diverse parameters possibly reducing the emittances were optimised. Such as the plasma electrode shape and temperature, the radio-frequency (RF) matching network for the igniter plasma, the filter-field strength and distribution, the strength of the axial magnetic field around the beam extraction hole, the cesiasion procedure and the cesium (Cs) density, impurity elements, and so on, were optimized with H ion sources for the Japan Proton Accelerator Research Complex (J-PARC). By optimizing each parameter step by step, the J-PARC cesiated RF-driven H ion source successfully produced the world brightest class beam with 95% beam transverse normalized rms emittances of 0.24 mmmrad and an intensity of 66 mA.
Shimojo, Kojiro
Nihon Ion Kokan Gakkai-Shi, 28(1), p.1 - 10, 2017/01
Development of metal separating reagents with high selectivity is necessary for efficient separation and recovery of valuable metals contained in industrial wastes, and removal and detection of toxic metals. We have developed novel metal separating ligands with a diglycolamic acid (DGAA) framework. The ligands have a tridentate coordination structure consisting of an amide group and a carboxy group connected by an ether chain and provide a metal separation ability superior to that of commercial ligands. Since the ligands can be synthesized simply in one step, this helps to reduce the production costs of the ligands. In the present review article, we report the extraction characteristics of DGAA-type ligand for 56 kinds of metal ions, extraction separation of rare-earth metal ions, and removal of toxic metal ions. Furthermore, a one-pot biological approach to fabricate DGAA-decorated gold nanoparticles has been developed using the DGAA-type ligand fused to the N-terminus of a gold-binding peptide. It was found that the DGAA-decorated gold nanoparticles can act as a high-sensitive colorimetric sensor for detecting toxic metal ions with color change.
Okajima, Satoshi; Takaya, Shigeru; Asayama, Tai
Nihon Kikai Gakkai Rombunshu (Internet), 83(845), p.16-00434_1 - 16-00434_13, 2017/01
no abstracts in English
Shobuda, Yoshihiro; Chin, Y. H.*; Saha, P. K.; Hotchi, Hideaki; Harada, Hiroyuki; Irie, Yoshiro*; Tamura, Fumihiko; Tani, Norio; Toyama, Takeshi*; Watanabe, Yasuhiro; et al.
Progress of Theoretical and Experimental Physics (Internet), 2017(1), p.013G01_1 - 013G01_39, 2017/01
Times Cited Count:14 Percentile:68.14(Physics, Multidisciplinary)The Rapid Cycling Synchrotron (RCS), whose beam energy ranges from 400 MeV to 3 GeV and which is located in the Japan Proton Accelerator Research Complex, is a kicker-impedance dominant machine, which violates the impedance budget from a classical viewpoint. Contrary to conventional understanding, we have succeeded to accelerate a 1-MW equivalent beam. The machine has some interesting features: for instance, the beam tends to be unstable for the smaller transverse beam size, the beam is stabilized by increasing the peak current . Space charge effects play an important role in the beam instability at the RCS. In this study, a new theory has been developed to calculate the beam growth rate with the head-tail and coupled-bunch modes () while taking space charge effects into account. The theory sufficiently explains the distinctive features of the beam instabilities at the RCS.
Takeyasu, Masanori
Tomioka Hoshasen Joho Matome Saito (Internet), 2 Pages, 2017/01
Some radiation measurement instruments are lent out to the residents in Tomioka-machi, Fukushima. In this paper, it is explained that the kinds of those instruments, their purposes, the attention points on their uses and the interpretation of the measurement results by those instruments.
Yamamoto, Masahiro
Zairyo To Kankyo, 66(1), p.3 - 12, 2017/01
The laboratory simulation tests which could be reproduced the corrosion reactions propagating in the actual environments were utilized to analyze the mechanism of corrosion phenomena. In this report, some results are introduced in the cases of maritime structures and nuclear facilities. Experimental apparatus was originally designed to obtain the data in high radioactive condition simulating actual plants. One is a result showing the effect of Np ion to the corrosion of stainless steel in nuclear fuel reprocessing plant. Corrosion mechanism was revealed that Np ion is reduced to Np ion by a corrosion reaction of stainless steel and then re-oxidized to Np ion in the bulk solution. And repetition of this cycle accelerated corrosion of stainless steel by a little amounts of Np addition in nitric acid solution. Another result is introduced that an effect of HO created by radiolysis of cooling water at high radioactive environment in light water reactor.
Yagmur, A.*; Uchida, Kenichi*; Ihara, Kazuki*; Ioka, Ikuo; Kikkawa, Takashi*; Ono, Madoka*; Endo, Junichi*; Kashiwagi, Kimiaki*; Nakashima, Tetsuya*; Kirihara, Akihiro*; et al.
Applied Physics Letters, 109(24), p.243902_1 - 243902_4, 2016/12
Times Cited Count:3 Percentile:14.94(Physics, Applied)Thermoelectric devices based on the spin Seebeck effect (SSE) were irradiated with gamma () rays with the total dose of around 310 Gy in order to investigate the -radiation resistance of the devices. To demonstrate this, Pt/NiZnFeO/Glass and Pt/BiYFeO/GdGaO SSE devices were used. We confirmed that the thermoelectric, magnetic, and structural properties of the SSE devices are not affected by the -ray irradiation. This result demonstrates that SSE devices are applicable to thermoelectric generation even in high radiation environments.
Sanada, Yukihisa; Orita, Tadashi; Torii, Tatsuo
Applied Radiation and Isotopes, 118, p.308 - 316, 2016/12
Times Cited Count:28 Percentile:93.3(Chemistry, Inorganic & Nuclear)An unmanned helicopter monitoring system (UHMS) was developed to survey the environmental effect of radioactive cesium scattered as a result of the Fukushima Daiichi Nuclear Power Station accident. The UHMS was mainly used to monitor the area surrounding the Fukushima Daiichi Nuclear Power Station six times from 2012 to 2015. Quantitative changes in the radioactivity distribution trend were revealed from the results of these monitorings runs.
Sawaguchi, Takuma; Tsukada, Manabu; Yamaguchi, Tetsuji; Mukai, Masayuki
Clay Minerals, 51(5), P. 815, 2016/12
ERRATUM; Effects of OH activity and temperature on the dissolution rate of compacted montmorillonite under highly alkaline conditions [Clay Minerals, vol.51, p.275 (2016), Corrected Fig. 7.]
Nagame, Yuichiro; Kratz, J. V.*; Schdel, M.*
EPJ Web of Conferences, 131, p.07007_1 - 07007_8, 2016/12
Times Cited Count:3 Percentile:72.98(Chemistry, Inorganic & Nuclear)Sato, Tetsuya; Asai, Masato; Borschevsky, A.*; Stora, T.*; Sato, Nozomi*; Kaneya, Yusuke; Tsukada, Kazuaki; Dllmann, C. E.*; Eberhardt, K.*; Eliav, E.*; et al.
EPJ Web of Conferences, 131, p.05001_1 - 05001_6, 2016/12
Times Cited Count:0 Percentile:0.9(Chemistry, Inorganic & Nuclear)Ionization efficiency in a surface ionization process depends on the first ionization potential of the atom. Based on the dependence, the ionization potential of the atom can be determined. We measured ionization efficiencies of fermium, einsteinium, mendelevium, and lawrencium by using a newly developed gas-jet coupled surface ion-source. The ionization potential of the elements have not been determined so far due to their low production rates and/or their short half-lives. Based on a relationship between the ionization efficiency and the ionization potential obtained via measurements of short-lived lanthanide isotopes, the ionization potentials of these actinide elements have been successfully determined.
Ishibashi, Masayuki; Sasao, Eiji; Hama, Katsuhiro
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 23(2), p.121 - 130, 2016/12
Matrix diffusion is one of the important phenomena for safety assessment of radioactive waste disposal because it has an effect of retarding the mass transport in crystalline rocks. Although there is not enough knowledge on the matrix diffusion in unaltered (intact) rocks around fractures. Intact granitic rocks around fractures are affected by primary alteration related to hydrothermal fluid resulting from crystallization of granitic magma. Therefore, detailed observations were carried out to clarify the effects of primary alteration focused on the intact granite around fractures sampled from the MIU, central Japan. The results of observation provide that the micropores are formed in plagioclases affected by primary alteration and have the potential of acting as matrix diffusion paths. This is indicating the possibility that intact granitic rock around fractures in an orogenic belt such as Japan have also the retardation functions due to matrix diffusion.
Nakayama, Shinichi; Okumura, Masahiko*; Nagasaki, Shinya*; Enokida, Yoichi*; Umeki, Hiroyuki*; Takase, Hiroyasu*; Kawasaki, Daisuke*; Hasegawa, Shuichi*; Furuta, Kazuo*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 23(2), p.131 - 148, 2016/12
A symposium "Science of nuclear fuel cycle and backend - Research and education -" was held at the Univer-sity of Tokyo in June 25, 2016. This aimed at developing the research on nuclear fuel cycle and backend. The time and the number of participants of the symposium were limited, but the active discussion was conducted, and the common perception for the future was shared among the experienced participants in those fields. This paper provides the discussions made in the symposium, and also, as a memory to Professor Ahn, the University of California, Berkeley, his prominent achievements in academic research and education.
Shimoyama, Iwao
Hoshasen To Sangyo, (141), p.7 - 11, 2016/12
Desulfurization is an indispensable process on hydrogen formation from fossil fuel. Adsorptive desulfurization, alternative to conventional hydrogenation desulfurization, requires development of stable activated carbon adsorbents with high performance. I study dopant dependence on thiophene adsorption for carbon alloys prepared by heteroatom doping using low-energy ion beam. I doped nitrogen and phosphorus as dopants of group 15 elements in graphite surfaces, and clarified that phosphorus is superior in thiophene adsorption to nitrogen, and that the effect of phosphorus is higher with room temperature doping than with high temperature doping by about 10 times. X-ray absorption spectroscopy indicated that local structures around phosphorus sites were different between them. I attribute the high adsorption property to formation of curved phosphorus sites prepared by room temperature doping. Above results suggest that the property of carbon alloy can be controlled by low-energy ion beam.
Sato, Wataru*; Komatsuda, Sayaka*; Osa, Akihiko; Sato, Tetsuya; Okubo, Yoshitaka*
Hyperfine Interactions, 237(1), p.113_1 - 113_6, 2016/12
Times Cited Count:2 Percentile:61.78(Physics, Atomic, Molecular & Chemical)The magnetic hyperfine field and electric field gradient at theCd( Cd) and Cd(In) probe nuclei introduced in a perovskite manganese oxide ( 250 K) were measured for the study of the local magnetism and structure by means of time-differential perturbed angular correlation spectroscopy. In the ferromagnetic phase at 77 K, a very slight supertransferred magnetic hyperfine field (SMHF) ( 0.014 T) combined with a well-defined electric field gradient was observed at the nonmagnetic Cd nucleus on the La/Ca A site. This observation suggests that the large magnetic hyperfine field ( = 6.9 T) measured, in our previous work, at the Ce probe nucleus on the A site originates from the contribution of a 4 spin oriented by the SMHF from adjacent Mn ions.
Noda, Yohei*; Koizumi, Satoshi*; Masui, Tomomi*; Mashita, Ryo*; Kishimoto, Hiromichi*; Yamaguchi, Daisuke; Kumada, Takayuki; Takata, Shinichi; Oishi, Kazuki*; Suzuki, Junichi*
Journal of Applied Crystallography, 49(6), p.2036 - 2045, 2016/12
Times Cited Count:19 Percentile:78.58(Chemistry, Multidisciplinary)Nakajima, Kunihisa
Mass Spectrometry (Internet), 5(2), p.S0055_1 - S0055_6, 2016/12
Though equilibrium vapor pressures are utilized to determine thermodynamic properties of not only gaseous species but also condensed phases, the obtained data often disagree by a factor of 100 and more. A new data analysis method is proposed using the so-called second and third law procedures to improve accuracy of vapor pressure measurements. It was found from examination of vapor pressures of cesium metaborate and silver that the analysis of the difference between the second and third law values can result in determination of an optimal data set. Since the new thermodynamic method does not require special techniques and or experiences in dealing with measured data, it is reliable and versatile to improve the accuracy of vapor pressure evaluation.
Ruiz-Barragan, S.*; Ribas Ario, J.*; Shiga, Motoyuki
Physical Chemistry Chemical Physics, 18(47), p.32438 - 32447, 2016/12
Times Cited Count:8 Percentile:32.26(Chemistry, Physical)The use of high-temperature liquid water (HTW) as a reaction medium is a very promising technology in the field of green chemistry. In order to fully exploit this technology, it is crucial to unravel the reaction mechanisms of the processes carried out in HTW. In this work, the reaction mechanism of 2,5-hexanediol dehydration in HTW has been studied by means of three different ab initio simulations: string method, metadynamics and molecular dynamics in real time. It is found that the whole reaction involving the protonation, bond exchange and the deprotonation occurs in a single step without a stable intermediate. The hydrogen bonded network of surrounding water has a vital role in assisting an efficient proton relay at the beginning and at the end of the reaction. It is confirmed that the reaction is energetically most favorable in the SN2 pathway with an estimated barrier of 36 kcal/mol, which explains the high stereo selectivity and the reaction rate observed in experiment.
Muramatsu, Toshiharu
Reza Kenkyu, 44(12), p.799 - 803, 2016/12
no abstracts in English
Oba, Yojiro*; Morooka, Satoshi; Sato, Hirotaka*; Sato, Nobuhiro*; Inoue, Rintaro*; Sugiyama, Masaaki*
Hamon, 26(4), p.170 - 173, 2016/11
Tsuda, Shuichi; Sato, Tatsuhiko; Ogawa, Tatsuhiko; Sasaki, Shinichi*
JPS Conference Proceedings (Internet), 11, p.060004_1 - 060004_6, 2016/11
Track structure and energy deposition around charged particle beams in microscopic site of a living cell is important information for understanding of biological effects of energetic heavy ion beams. In this work, measurements of lineal energy () distributions for various kinds of ion beams have been performed for the verification of the microdosimetric function that incorporated in the PHITS code. In the international symposium focused on radiation detectors, the wall-less tissue equivalent proportional counter that developed in this study to measure distributions will be introduced, together with a series of data.
Matsunaga, Takeshi; Nakanishi, Takahiro; Atarashi-Andoh, Mariko; Takeuchi, Erina; Muto, Kotomi; Tsuzuki, Katsunori; Nishimura, Shusaku; Koarashi, Jun; Otosaka, Shigeyoshi; Sato, Tsutomu*; et al.
Journal of Radioanalytical and Nuclear Chemistry, 310(2), p.679 - 693, 2016/11
Times Cited Count:6 Percentile:49.29(Chemistry, Analytical)Particulate Cs in stream water was collected continuously for two years in order to assess the long-term trend of the Cs discharge from the forest environment. Sampling was conducted from December 2011 to December 2013 in a mountainous stream, which received the Cs from the Fukushima Daiichi Nuclear Power Plant accident. A seasonal increase in fluvial transport load of particulate Cs associated with suspended solids (SS) was observed in August and September when rainfall was abundant. The particulate Cs concentration decreased at a faster rate than the rate due to radioactive decay. This decrease might be resulted from redistribution of the easily eroded and polluted soil surface due to heavy rain events such as typhoons. These findings indicate that the particulate Cs load was subject to the inter-annual variations in rainfalls, and decreased gradually over a long period of time due to a decrease in Cs concentration in SS.
Sueyoshi, Tetsuro*; Kotaki, Tetsuya*; Uraguchi, Yusei*; Suenaga, Momotaro*; Makihara, Takahiro*; Fujiyoshi, Takanori*; Ishikawa, Norito
Physica C, 530, p.72 - 75, 2016/11
Times Cited Count:9 Percentile:41.22(Physics, Applied)In order to clarify the influence of size and spatial distribution of three-dimensional pinning centers (3D-PCs) on hybrid flux pinning, columnar defects (CDs) were installed by using 200 MeV Xe ions along the -axis direction into quasi-multilayered films consisting of YBaCuOy layers and pseudo layers of BaSnO. The positive effect of the BaSnO doping on the hybrid flux pinning stands out for the critical current density around in high magnetic field and/or inclined magnetic field off the -axis, whereas there is little difference in the at among the same growth temperature samples for low magnetic field. In the case of the in-plane distributed BaSnO nano-dots, the Jc around is remarkably enhanced, whereas there is a detrimental effect on the Jc around . These imply that the tuning of 3D-PCs is one of the keys to improve the at all magnetic field orientations for the hybrid flux pinning.
Onuma, Yuichi; Matsuo, Mamoru; Maekawa, Sadamichi
Physical Review B, 94(18), p.184405_1 - 184405_5, 2016/11
Times Cited Count:23 Percentile:67.71(Materials Science, Multidisciplinary)We theoretically investigate spin transport in half-metallic ferromagnets at finite temperatures. The side-jump and skew-scattering contributions to spin Hall conductivity are derived using the Kubo formula. The electron-magnon interaction causes a finite density of states in the energy gap of the minority-spin band and induces spin Hall conductivity. We show that spin Hall conductivity is proportional to , with being temperature and is sensitive to . We propose that spin Hall conductivity may be a tool to study the minority-spin state.
Matsumoto, Toshinori; Kawabe, Ryuhei; Sugiyama, Tomoyuki; Maruyama, Yu
Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 9 Pages, 2016/11
During severe accident at nuclear power stations, molten core material jet could be discharged from the reactor pressure vessel into the water pool formed at the pedestal or cavity in the containment vessel. To improve the JASMINE code, The method for determining particle diameters which follow the Rosin-Rammler distribution was implemented. The jet breakup experiments, DEFOR-A conducted by KTH (Royal Institute of Technology, Sweden) were analyzed with the code. The influence of the experimental conditions, such as water subcooling, melt jet diameter and superheat were discussed. A crust layer formation model was also implemented in the code. The analyses using the model were carried out for the melt spreading experiments, PULiMS conducted by KTH. The spreading area was overestimated. Further improvement of the melt spreading model were discussed to close the gaps by introducing additional models such as heat conduction in the substrate materials, void formed inside the melt and so on.
Sato, Masatoshi; Matsumoto, Toshinori; Sugiyama, Tomoyuki; Maruyama, Yu
Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 10 Pages, 2016/11
Kawamura, Takuma; Noda, Tomoyuki; Idomura, Yasuhiro
Proceedings of 2nd Workshop on In Situ Infrastructures for Enabling Extreme-scale Analysis and Visualization (ISAV 2016) (Internet), p.18 - 22, 2016/11
Times Cited Count:9 Percentile:90.83(Computer Science, Interdisciplinary Applications)A novel in-situ online visualization framework is developed based on the Particle Based Volume Rendering (PBVR), which renders multivariate volume data using view-independent particle data. Our online approach enables visualization of particle data with interactive view exploration and changes of multi-dimensional transfer functions at runtime. The runtime visualization show excellent strong scaling up to thousands of cores, and its computational cost is small. These features enable flexible in-situ data exploration for monitoring extreme scale simulations. The utility of the proposed framework is demonstrated by applying it to simulations of molten debris relocation in reactor pressure vessels using the JUPITER code.
Mayumi, Akie; Idomura, Yasuhiro; Ina, Takuya; Yamada, Susumu; Imamura, Toshiyuki*
Proceedings of 7th Workshop on Latest Advances in Scalable Algorithms for Large-Scale Systems (ScalA 2016) (Internet), p.17 - 24, 2016/11
The left-preconditioned communication avoiding conjugate gradient (LP-CA-CG) method is applied to the pressure Poisson equation in the multiphase CFD code JUPITER. The arithmetic intensity of the LP-CA-CG method is analyzed, and is dramatically improved by loop splitting for inner product operations and for three term recurrence operations. Two LP-CA-CG solvers with block Jacobi preconditioning and with underlap preconditioning are developed. It is shown that on the K computer, the LP-CA-CG solvers with block Jacobi preconditioning is faster, because the performance of local point-to-point communications scales well, and the convergence property becomes worse with underlap preconditioning. The LP-CA-CG solver shows good strong scaling up to 30,000 nodes, where the LP-CA-CG solver achieved higher performance than the original CG solver by reducing the cost of global collective communications by 69%.
Noguchi, Hiroki; Takegami, Hiroaki; Kamiji, Yu; Tanaka, Nobuyuki; Iwatsuki, Jin; Kasahara, Seiji; Kubo, Shinji
Proceedings of 8th International Topical Meeting on High Temperature Reactor Technology (HTR 2016) (CD-ROM), p.1029 - 1038, 2016/11
JAEA has been conducting R&D on the IS process for nuclear-powered hydrogen production. We have constructed a 100 NL/h-H-scale test apparatus made of industrial materials. At first, we investigated performance of components in this apparatus. In this paper, the test results of HSO decomposition, HI distillation, and HI decomposition were shown. In the HSO section, O production rate is proportional to HSO feed rate and SO decomposition ratio was estimated about 80%. In HI distillation section, we confirmed to acquire a concentrated HI solution over azeotropic HI composition in the condenser. In HI decomposition section, H could be produced stably by HI decomposer and decomposition ratio was about 18%. The HSO decomposer, the HI distillation column, and the HI decomposer were workable. Based on the results added to that shown in Series I, we conducted a trial continuous operation and succeeded it for 8 hours.
Tanaka, Nobuyuki; Takegami, Hiroaki; Noguchi, Hiroki; Kamiji, Yu; Iwatsuki, Jin; Aita, Hideki; Kasahara, Seiji; Kubo, Shinji
Proceedings of 8th International Topical Meeting on High Temperature Reactor Technology (HTR 2016) (CD-ROM), p.1022 - 1028, 2016/11
Japan Atomic Energy Agency (JAEA) has manufactured 100 NL/h-H-scale hydrogen test apparatus. In advance to conduct the continuous operation, we investigated performance of the components in each section of the IS process. In this paper, the results of test of Bunsen and HI concentration sections was shown. In Bunsen reaction, section, we confirmed that outlet gas flow rate included no SO gas, indicating that all the feed SO gas was absorbed to the solution in the Bunsen reactor for the Bunsen reaction. On the basis of these results, we evaluated that Bunsen reactor was workable. In HI concentration section, HI concentration was conducted by EED stack. As a result, it can concentrate HI in HIx solution as theoretically predicted on the basis of the previous paper. Based on the results added to that shown in Series II, we have conducted a trial continuous operation and succeeded it for 8 hours.
Oigawa, Hiroyuki
Enerugi Rebyu, 36(10), p.10 - 11, 2016/10
Japan Atomic Energy Agency is conducting wide range of research and development on nuclear power such as those for response to the accident at the Fukushima Daiichi Nuclear Power Plant, improvement of nuclear power safety, establishment of fast reactor technology and nuclear fuel cycle, countermeasure to back-end of nuclear power, basic and fundamental research, and human resource development, in order to solve various problems concerning nuclear power and to explore possibility of more sophisticated utilization of nuclear technology. Hereafter, we would like to contribute to the creation of innovation originated in Japan by enhancing collaboration with other national research and development organizations, universities and private companies and by maximizing outcomes of research and development in Japan.
Motai, Satoko*; Mukai, Hiroki*; Watanuki, Tetsu; Owada, Kenji; Fukuda, Tatsuo; Machida, Akihiko; Kuramata, Chisaki*; Kikuchi, Ryosuke*; Yaita, Tsuyoshi; Kogure, Toshihiro*
Journal of Mineralogical and Petrological Sciences, 111(5), p.305 - 312, 2016/10
Times Cited Count:16 Percentile:51.74(Mineralogy)no abstracts in English
Manabe, Sachi; Matsubara, Natsumi; Saegusa, Jun; Takeishi, Minoru
KEK Proceedings 2016-8, p.281 - 285, 2016/10
no abstracts in English
Oh, J.*; Le, M. D.*; Nahm, H.-H.*; Sim, H.*; Jeong, J.*; Perring, T. G.*; Woo, H.*; Nakajima, Kenji; Kawamura, Seiko; Yamani, Z.*; et al.
Nature Communications (Internet), 7, p.13146_1 - 13146_6, 2016/10
Times Cited Count:56 Percentile:86.85(Multidisciplinary Sciences)Magnons and phonons are fundamental quasiparticles in a solid and can be coupled together to form a hybrid quasi-particle. However, detailed experimental studies on the underlying Hamiltonian of this particle are rare for actual materials. Moreover, the anharmonicity of such magnetoelastic excitations remains largely unexplored, although it is essential for a proper understanding of their diverse thermodynamic behaviour and intrinsic zero-temperature decay. Here we show that in non-collinear antiferromagnets, a strong magnon phonon coupling can significantly enhance the anharmonicity, resulting in the creation of magnetoelastic excitations and their spontaneous decay. By measuring the spin waves over the full Brillouin zone and carrying out anharmonic spin wave calculations using a Hamiltonian with an explicit magnon phonon coupling, we have identified a hybrid magnetoelastic mode in (Y,Lu)MnO and quantified its decay rate and the exchange-striction coupling termrequired to produce it.
Gu, B.; Maekawa, Sadamichi
Physical Review B, 94(15), p.155202_1 - 155202_8, 2016/10
Times Cited Count:19 Percentile:64.68(Materials Science, Multidisciplinary)Shibamoto, Yasuteru; Yonomoto, Taisuke; Ishigaki, Masahiro; Abe, Satoshi
Proceedings of 11th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operation and Safety (NUTHOS-11) (USB Flash Drive), 10 Pages, 2016/10
Sueyoshi, Tetsuro*; Nishimura, Takahiro*; Fujiyoshi, Takanori*; Mitsugi, Fumiaki*; Ikegami, Tomoaki*; Ishikawa, Norito
Superconductor Science and Technology, 29(10), p.105006_1 - 105006_7, 2016/10
Times Cited Count:8 Percentile:37.83(Physics, Applied)A systematic investigation of flux pinning by widely direction-dispersed columnar defects (CDs) in YBaCuOy thin films was carried out by using heavy-ion irradiation: a parallel configuration of CDs aligned along the -axis, and two trimodal splay configurations composed of crossing CDs; relative to the -axis, where the splay plane defined by the three irradiation angles is perpendicular (trimodal-A) or parallel (trimodal-B) to the transport current direction. The trimodal configurations show high pinning efficiency over a wide range of magnetic field orientations compared to the parallel one at low magnetic field. In particular, trimodal-B shows the higher critical current density of the two trimodal configurations.
Sato, Tetsuya
Genshikaku Kenkyu, 61(1), p.96 - 106, 2016/09
We successfully determined the first ionization potential of lawrencium (Lr, Z=103). The result experimentally substantiated for the first time that Lr is the last member of the actinide series. Measured ionization potential suggested that Lr atom would have the electronic configuration which is different from the configuration expected based on the Periodic table. For the measurement, we have developed a novel method applied the surface ionization process. Public responses after the publication are also introduced.
Nakamura, Hiroki; Machida, Masahiko
Journal of Nuclear Materials, 478, p.56 - 60, 2016/09
Times Cited Count:8 Percentile:60.26(Materials Science, Multidisciplinary)Thorium has been considered a potential nuclear fuel for decades. To develop evaluation method for high-temperature properties of thorium dioxide as a candidate nuclear fuel, we perform first-principles molecular dynamics. The calculated enthalpy and thermal expansion agree well with the observed data. The Bredig transition temperature also coincides with experiments. Our results indicate that this method can provide reliable data of thermal properties of nuclear fuels.
Noguchi, Yoshifumi*; Hiyama, Miyabi*; Shiga, Motoyuki; Sugino, Osamu*; Akiyama, Hidefumi*
Journal of Physical Chemistry B, 120(34), p.8776 - 8783, 2016/09
Times Cited Count:6 Percentile:15.29(Chemistry, Physical)We investigated the stability of oxyluciferin anions (keto, enol, and enolate isomers) in aqueous solution at room temperature by performing a nanosecond time scale first-principles molecular dynamics simulation. In contrast to all previous quantum chemistry calculations, which suggested the keto-type to be the most stable, we show that the enol-type is slightly more stable than the keto-type, in agreement with some recent experimental studies. The simulation highlights the remarkable hydrophobicity of the keto-type by the cavity formed at the oxyluciferin-water interface as well as a reduction in hydrophobicity with the number of hydrating water molecules. It is therefore predicted that the isomeric form in a hydrated cluster is size-dependent.
Shobuda, Yoshihiro; Chin, Y. H.*
Physical Review Accelerators and Beams (Internet), 19(9), p.094201_1 - 094201_24, 2016/09
Times Cited Count:5 Percentile:39.53(Physics, Nuclear)In a so-called waveguide FEL for THz radiations, an extremely small aperture (mm) waveguide is used to confine angularly wide spread radiation fields from a low energy electron beam into a small area. This confinement increases the interaction between the electron beam and the radiation fields to achieve a much higher FEL gain. The radiation fields propagate inside the waveguide as waveguide modes, not like a light flux in a free space FEL. This characteristic behavior of the radiation fields makes intuitive understanding of the waveguide FEL difficult. We developed a three-dimensional waveguide FEL theory to calculate a gain of THz waveguide FEL including the effects of the energy spread, the beam size and the beta Tron oscillations of an electron beam, and effects of a rectangular waveguide. The FEL gain can be calculated as a function of frequency by solving the dispersion relation. Theoretical gains are compared with simulation results for a waveguide FEL with a planar undulator similar to the KAERI one. Good agreements are obtained.
Amaya, Masaki; Udagawa, Yutaka; Narukawa, Takafumi; Mihara, Takeshi; Taniguchi, Yoshinori
Proceedings of Annual Topical Meeting on LWR Fuels with Enhanced Safety and Performance (TopFuel 2016) (USB Flash Drive), p.53 - 62, 2016/09
In order to evaluate adequacy of present safety criteria and safety margins in terms of advanced fuels and provide a database for future regulation on them, JAEA started an extensive research program called ALPS-II program, which has been sponsored by NRA, Japan. This program is primarily composed of tests simulating a RIA and a LOCA on the high-burnup advanced fuels irradiated in commercial PWR or BWR. Recently, the failure limits of the high-burnup advanced fuels under RIA conditions were investigated at NSRR, and post-test examinations on the fuel rods after the pulse irradiation tests are being performed. In terms of the simulated LOCA test, integral thermal shock tests and high temperature oxidation tests were carried out at RFEF, and the fracture limits, high temperature oxidation rate, etc. of the high-burnup advanced fuel cladding were investigated. This paper mainly describes some recent experimental results obtained in this program with respect to RIA and LOCA.
Negyesi, M.; Amaya, Masaki
Proceedings of Annual Topical Meeting on LWR Fuels with Enhanced Safety and Performance (TopFuel 2016) (USB Flash Drive), p.1065 - 1074, 2016/09
Taniguchi, Yoshinori; Udagawa, Yutaka; Amaya, Masaki
Proceedings of Annual Topical Meeting on LWR Fuels with Enhanced Safety and Performance (TopFuel 2016) (USB Flash Drive), p.229 - 238, 2016/09
Kerisit, S.*; Okumura, Masahiko; Rosso, K. M.*; Machida, Masahiko
Clays and Clay Minerals, 64(4), p.389 - 400, 2016/08
Times Cited Count:29 Percentile:74.44(Chemistry, Physical)no abstracts in English
Uesaka, Mitsuru*; Mineo, Hideaki
Nihon Genshiryoku Gakkai-Shi ATOMO, 58(8), p.468 - 473, 2016/08
All the research reactors and critical assemblies (hereinafter RRCAs) in Japan are stopped in order to fulfil the new regulatory requirements, which were reinforced after the accident at the Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Station. These RRCAs have played important roles in the areas of human resource development, academic research, medical and industrial application of nuclear technology. Prolonged stoppage of RRCAs affects adversely those activities. Atomic Energy Society of Japan set up a group to discuss this issue. The group has shown a proposal that the roles of the RRCAs, which are indispensable facilities to nuclear human resource development, should be placed positively in the energy policy and the science and technology policy of the country.
Tamura, Kazuhisa; Nishihata, Yasuo
Journal of Physical Chemistry C, 120(29), p.15691 - 15697, 2016/07
Times Cited Count:9 Percentile:31.88(Chemistry, Physical)The behavior of halide ions on the Au(111) electrode surface in two ionic liquids (ILs) was investigated by monitoring the structure of the electrode surface. The potential dependences of the X-ray diffraction intensity, which originate from the Au(111)-(11) structure and the surface normal structure, were measured simultaneously with cyclic voltammograms. The results revealed that halide ions are co-adsorbed with IL molecules on the electrode surface and increase the mobility of surface atoms. This suggests that the interaction between halide ions and surface Au atoms is weaker than that between IL molecules and surface Au atoms; that is, the surface properties are mainly governed by adsorbed IL molecules. Furthermore, a comparison of the two ILs revealed that the effect of halide ions on the structure of the Au(111) electrode surface depends on the strength of the interaction between IL molecules and surface Au atoms.
Yasuoka, Hiroshi; Motoya, Kiyoichiro*; Majumder, M.*; Witt, S.*; Kerllner, C.*; Baenitz, M.*
Journal of the Physical Society of Japan, 85(7), p.073701_1 - 073701_4, 2016/07
Times Cited Count:3 Percentile:27.79(Physics, Multidisciplinary)Sasa, Narimasa; Yamada, Susumu; Machida, Masahiko; Imamura, Toshiyuki*
Nonlinear Theory and Its Applications, IEICE (Internet), 7(3), p.354 - 361, 2016/07
A round off error accumulation in iterative use of the FFT is discussed. By using numerical simulations of partial differential equations, we numerically show that the round off error in iterative use of the FFT tend to be accumulated. To avoid a lack of precision, we give numerical simulations by using a quadruple precision floating point number, which ensure a sufficient precision against the round off errors by the FFT.
Nomura, Takuji*; Harada, Yoshihisa*; Niwa, Hideharu*; Ishii, Kenji*; Ishikado, Motoyuki*; Shamoto, Shinichi; Jarrige, I.*
Physical Review B, 94(3), p.035134_1 - 035134_9, 2016/07
Times Cited Count:11 Percentile:47.12(Materials Science, Multidisciplinary)Low-energy electron excitation spectra were measured on a single crystal of a typical iron-based superconductor PrFeAsO using resonant inelastic X-ray scattering (RIXS) at the Fe- edge.
Komatsu, Kazuki*; Noritake, Fumiya*; Machida, Shinichi*; Sano, Asami; Hattori, Takanori; Yamane, Ryo*; Kagi, Hiroyuki*
Scientific Reports (Internet), 6, p.28920_1 - 28920_11, 2016/07
Times Cited Count:23 Percentile:54.81(Multidisciplinary Sciences)We investigate in-situ neutron diffraction measurements and density functional theory calculations to revisit the structure and stability of ice XV. We find that none of the completely ordered configurations are particular favored; instead, partially ordered states are established as a mixture of ordered domains in disordered ice VI. This scenario in which several kinds of ordered configuration coexist dispels the contradictions in previous studies. It means that the order disorder pairs in ice polymorphs are not one-to-one correspondent pairs but rather have one-to-n correspondence, where there are possible configurations at finite temperature.
Minoshima, Yusuke*; Seki, Yusuke*; Takayanagi, Toshiyuki*; Shiga, Motoyuki
Chemical Physics, 472, p.1 - 8, 2016/06
Times Cited Count:2 Percentile:6.19(Chemistry, Physical)The dynamical process of electron attachment to a guanine-cytosine pair in the normal (h-GC) and deuterated (d-GC) forms has been studied theoretically by semiclassical ring-polymer molecular dynamics (RPMD) simulations using the empirical valence bond model. The initially formed dipole-bound anion is converted rapidly to the valence-bound anion within about 0.1 ps in both h-GC and d-GC. However, the subsequent proton transfer in h-GC occurs with a rate five times greater than the deuteron transfer in d-GC. The change of rates with isotopic substitution and temperature variation in the RPMD simulations are quantitatively and qualitatively different from those in the classical molecular dynamics (MD) simulations, demonstrating the importance of nuclear quantum effects on the dynamics of this system.
Yamane, Yuta*; Ieda, Junichi; Sinova, J.*
Physical Review B, 93(18), p.180408_1 - 180408_5, 2016/05
Times Cited Count:17 Percentile:61.21(Materials Science, Multidisciplinary)Gunji, Satoshi; Tonoike, Kotaro; Izawa, Kazuhiko; Sono, Hiroki
Proceedings of International Conference on the Physics of Reactors; Unifying Theory and Experiments in the 21st Century (PHYSOR 2016) (USB Flash Drive), p.3927 - 3936, 2016/05
Criticality safety of fuel debris including MCCI products is one of the major safety is-sues for decommissioning of Fukushima Daiichi Nuclear Power Station. Criticality or subcriticality condition of the fuel debris is still uncertain since its composition, location, neutron moderation, etc. are not confirmed. Also uncertain in criticality control of fuel debris is the effectiveness of neutron poison in cooling water. A database is being built by computation in JAEA, covering a wide range of possible conditions of such composition, neutron moderation, etc., to facilitate assessing criticality characteristics when fuel debris samples are taken and their conditions are known. The computation also has uncertainties to be clarified by critical experiments, which is planned by JAEA to be conducted with the modified STACY and samples simulating fuel debris compositions. This report introduces a study of experimental core configurations for reactivity worth measurements of samples simulating MCCI products. It is concluded that the measurement is feasible in both under- and over-moderated conditions. Additionally, required amount of samples was estimated.
Tomioka, Naotaka*; Okuchi, Takuo*; Purevjav, N.*; Abe, Jun*; Harjo, S.
Physics and Chemistry of Minerals, 43(4), p.267 - 275, 2016/04
Times Cited Count:8 Percentile:28.75(Materials Science, Multidisciplinary)Udagawa, Yutaka; Sugiyama, Tomoyuki; Amaya, Masaki
Proceedings of 2016 International Congress on Advances in Nuclear Power Plants (ICAPP 2016) (CD-ROM), p.1183 - 1189, 2016/04
Takeda, Seiji
Strlevern Rappot 2016:5 (Internet), p.43 - 46, 2016/04
A large volume of disaster wastes such as concrete waste, scrap metal, wood waste and so on, in the environment due to the accident at the Fukushima Nuclear Power Plant has been contaminated by radioactive cesium (Cs and Cs). A large challenge has been how to handle the large volume of contaminated material. One strategy for addressing this issue would be the reuse of material from the viewpoint of both effective utilization of resources and the amount of reduction of the contaminants. This paper shows that the outline of dose estimation for some kinds of reuse applications to derive the radioactive cesium concentration in reusable materials.
Oigawa, Hiroyuki
Hoshasei Haikibutsu Genyoka, Yugai Teigen No Gijutsu Kaihatsu, Kakushu Bunri, Tenkan; NSA/Commentaries, No.22, p.38 - 50, 2016/03
An Accelerator-Driven System (ADS) is a hybrid nuclear system coupling a subcritical reactor consisting of minor actinide fuels with a spallation neutron source driven by a high-power proton accelerator, aiming at effective transmutation of MA contained in high-level radioactive wastes. An ADS with thermal power of 800MW can transmute MA produced in 10 light water reactors with electric power of 1GW. To realize ADS, we should solve various technical challenges such as a high-power accelerator, a spallation target, a subcritical reactor, recycle technology of MA fuel, and so on. JAEA is conducting research and development to solve these technical challenges with making use of international collaborations, and planning a new experimental program using J-PARC.
Honda, Mitsunori; Shimoyama, Iwao; Okamoto, Yoshihiro; Baba, Yuji; Suzuki, Shinichi; Yaita, Tsuyoshi
Journal of Physical Chemistry C, 120(10), p.5534 - 5538, 2016/03
Times Cited Count:20 Percentile:57.75(Chemistry, Physical)Chen, Y.-T.*; Takahashi, Saburo*; Nakayama, Hiroyasu*; Althammer, M.*; Goennenwein, S. T. B.*; Saito, Eiji; Bauer, G. E. W.*
Journal of Physics; Condensed Matter, 28(10), p.103004_1 - 103004_15, 2016/03
Times Cited Count:81 Percentile:61.66(Physics, Condensed Matter)We review the so-called spin Hall magnetoresistance (SMR) in bilayers of a magnetic insulator and a metal, in which spin currents are generated in the normal metal by the spin Hall effect. The associated angular momentum transfer to the ferromagnetic layer and thereby the electrical resistance is modulated by the angle between the applied current and the magnetization direction. The SMR provides a convenient tool to non-invasively measure the magnetization direction and spin-transfer torque to an insulator. We introduce the minimal theoretical instruments to calculate the SMR, i.e. spin diffusion theory and quantum mechanical boundary conditions. This leads to a small set of parameters that can be fitted to experiments. We discuss the limitations of the theory as well as alternative mechanisms such as the ferromagnetic proximity effect and Rashba spin-orbit torques, and point out new developments.
Soda, Minoru*; Homma, Yuki*; Takamizawa, Satoshi*; Kawamura, Seiko; Nakajima, Kenji; Masuda, Takatsugu*
Journal of the Physical Society of Japan, 85(3), p.034717_1 - 034717_9, 2016/03
Times Cited Count:1 Percentile:11.46(Physics, Multidisciplinary)Inelastic neutron scattering experiments are performed on the nanoporous metal complex Cu--1,4-cyclohexanedicarboxylic acid (Cu-CHD) adsorbing O molecules to identify the spin model of the O-based magnet realized in the host complex. It is found that the magnetic excitations of Cu-CHDs adsorbing low- and high-concentration O molecules are explained by different spin models, the former by spin dimers and the latter by spin trimers. By using the obtained parameters and by assuming that the levels of the group of the highest energy states are reduced because of the nonnegligible spin dependence of the molecular potential of oxygen, the magnetization curves are explained quantitatively.
Takino, Kazuo; Arai, Masaji; Murayama, Yoji
Proceedings of International Topical Meeting on Research Reactor Fuel Management and Meeting of the International Group on Reactor Research (RRFM/IGORR 2016) (Internet), p.667 - 676, 2016/03
Our working group has started to investigate basic concepts of the new research reactor which foresaw twenty years later. The aim of this project is to build up the design of new multipurpose research reactor which is constructed instead of JRR-3 for utilization of the neutron beam, irradiation, training and so on.
Kirihara, Akihiro*; Kondo, Koichi*; Ishida, Masahiko*; Ihara, Kazuki*; Iwasaki, Yuma*; Someya, Hiroko*; Matsuba, Asuka*; Uchida, Kenichi*; Saito, Eiji; Yamamoto, Naoharu*; et al.
Scientific Reports (Internet), 6, p.23114_1 - 23114_7, 2016/03
Times Cited Count:62 Percentile:90.69(Multidisciplinary Sciences)Heat-flow sensing is expected to be an important technological component of smart thermal management in the future. Conventionally, the thermoelectric (TE) conversion technique, which is based on the Seebeck effect, has been used to measure a heat flow by converting the flow into electric voltage. However, for ubiquitous heat-flow visualization, thin and flexible sensors with extremely low thermal resistance are highly desired. Recently, another type of TE effect, the longitudinal spin Seebeck effect (LSSE), has aroused great interest because the LSSE potentially offers favourable features for TE applications such as simple thin-film device structures. Here we demonstrate an LSSE-based flexible TE sheet that is especially suitable for a heat-flow sensing application. This TE sheet contained a NiZnFeO film which was formed on a flexible plastic sheet using a spray-coating method known as ferrite plating. The experimental results suggest that the ferrite-plated film, which has a columnar crystal structure aligned perpendicular to the film plane, functions as a unique one-dimensional spin- current conductor suitable for bendable LSSE-based sensors. This newly developed thin TE sheet may be attached to differently shaped heat sources without obstructing an innate heat flux, paving the way to versatile heat-flow measurements and management.
Ruiz-Barragan, S.*; Ishimura, Kazuya*; Shiga, Motoyuki
Chemical Physics Letters, 646, p.130 - 135, 2016/02
Times Cited Count:15 Percentile:55.76(Chemistry, Physical)A hierarchical parallelization has been implemented in a new unified code PIMD-SMASH for simulation where the replicas and the Born-Oppenheimer forces are parallelized. It is demonstrated that ab initio path integral molecular dynamics simulations can be carried out very efficiently for systems up to a few tens of water molecules. The code was then used to study a Diels-Alder reaction of cyclopentadiene and butenone by ab initio string method. A reduction in the reaction energy barrier is found in the presence of hydrogen-bonded water, in accordance with experiment.