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Journal Articles

Valence control of charge and orbital frustrated system YbFe$$_{2}$$O$$_{4}$$ with electrochemical Li$$^{+}$$ intercalation

Murase, Satoshi*; Yoshikawa, Yumi*; Fujiwara, Kosuke*; Fukada, Yukimasa*; Teranishi, Takashi*; Kano, Jun*; Fujii, Tatsuo*; Inada, Yasuhiro*; Katayama, Misaki*; Yoshii, Kenji; et al.

Journal of Physics and Chemistry of Solids, 162, p.110468_1 - 110468_6, 2022/03

We report a trial of the valence control for mixed valence iron triangular oxide YbFe$$_{2}$$O$$_{4}$$ in order to develop an effective technique to control the frustration of charges in strongly correlated electron systems. The electro-chemical doping of Li$$^{+}$$ into YbFe$$_{2}$$O$$_{4}$$ was examined on the cell type sample similar to the Li-ion secondary battery cell. Systematic change of the lattice constant, Fe-Fe and Fe-Yb distance were observed with Li doping. Maximum value of the doping was over 300 mAh/g. An EXAFS experiment indicated that Li positioned between Yb octahedron layer (U-layer) and Fe-bipyramidal layer (W-layer). However, detailed change of iron valence state of YbFe$$_{2}$$O$$_{4}$$ was not clearly observed because of the superimpose of the signal from iron metal nano particles in XANES observation. The results indicate that the electrochemical method might be one of the potential technique to control the frustration of charges in YbFe$$_{2}$$O$$_{4}$$.

Journal Articles

Separation and recovery of long-lived fission products from high level radioactive waste using electrochemical technique

Kanamura, Shohei*; Takahashi, Yuya*; Omori, Takashi*; Nohira, Toshiyuki*; Sakamura, Yoshiharu*; Matsumura, Tatsuro

Denki Kagaku, 88(3), p.289 - 290, 2020/09

no abstracts in English

Journal Articles

Zr separation from high-level liquid waste with a novel hydroxyacetoamide type extractant

Morita, Keisuke; Suzuki, Hideya; Matsumura, Tatsuro; Takahashi, Yuya*; Omori, Takashi*; Kaneko, Masaaki*; Asano, Kazuhito*

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.464 - 468, 2019/09

High level liquid waste (HLLW) contains several radionuclides with half-lives longer than 10$$^{6}$$ year. For reduce environmental burden of waste disposal, minor actinoids and long-lived fission products will to be partitioned and transmuted. JAEA and Toshiba developed process for recovering Se, Zr, Pd and Cs from HLLW. Solvent extraction for Zr with novel extractant, ${it N,N}$-didodecyl-2-hydroxyacetoamide (HAA) was detailed. The HAA system showed high selectivity for Zr, as indicated by the extraction order of Zr $$>$$ Mo $$>$$ Pd $$>$$ Ag $$approx$$ Sb $$>$$ Sn $$>$$ Lns $$>$$ Fe. The extracted species was determined as Zr(HAA)$$_{3}$$(NO$$_{3}$$)$$_{4}$$(HNO$$_{3}$$)$$_{x}$$. A continuous countercurrent extraction with HAA was applied to a simulated, concentrated HLLW after Pd, Se, and Cs removal, where the quantitative extraction of Zr and Mo was effectively demonstrated.

Journal Articles

Incorporation of multinuclear copper active sites into nitrogen-doped graphene for electrochemical oxygen reduction

Kato, Masaru*; Muto, Marika*; Matsubara, Naohiro*; Uemura, Yohei*; Wakisaka, Yuki*; Yoneuchi, Tsubasa*; Matsumura, Daiju; Ishibara, Tomoko*; Tokushima, Takashi*; Noro, Shinichiro*; et al.

ACS Applied Energy Materials (Internet), 1(5), p.2358 - 2364, 2018/05

 Times Cited Count:4 Percentile:26.29(Chemistry, Physical)

Journal Articles

Fine dispersion of Pt$$_{4-5}$$ subnanoclusters and Pt single atoms over porous carbon supports and their structural analyses with X-ray absorption spectroscopy

Itoi, Hiroyuki*; Nishihara, Hirotomo*; Kobayashi, Shunsuke*; Ittisanronnachai, S.*; Ishii, Takafumi*; Berenguer, R.*; Ito, Masashi*; Matsumura, Daiju; Kyotani, Takashi*

Journal of Physical Chemistry C, 121(14), p.7892 - 7902, 2017/04

 Times Cited Count:26 Percentile:78.77(Chemistry, Physical)

Journal Articles

LET dependency of human normal dermal cells survival in carbon ion irradiation

Yoshida, Yukari*; Mizohata, Kensuke*; Matsumura, Akihiko*; Isono, Mayu*; Yako, Tomoko*; Nakano, Takashi*; Funayama, Tomoo; Kobayashi, Yasuhiko; Kanai, Tatsuaki*

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 81, 2015/03

In the clinical application of carbon-ion (C-ion) radiation therapy in Japan, different RBE values of carbons have been used for clinical and biological endpoints. The biological RBE (bRBE) was estimated by a method that is based on the linear-quadratic (LQ) model, and was defined ${it in vitro}$ at the 10% surviving fraction of human salivary gland (HSG) tumor cells. However, many of biological parameters, that is, type of tissues, different sort of cells, oxygenation levels, and all, could affect radiosensitivity. Thus, normal human dermal fibroblasts (NHDF) cells were exposed to C-ion beams at Gunma University (10-80 keV/micrometer) and TIARA (108 and 158 keV/micrometer). The surviving fractions were analyzed with colony formation assays. The experimental RBE (eRBE) values were estimated from the radiation dose survival curve fitted by LQ model, and defined ${it in vitro}$.

Journal Articles

Cs adsorption mechanism on clay minerals based on material sciences using synchrotron radiation and first principle calculation

Yaita, Tsuyoshi; Kobayashi, Toru; Ikeda, Takashi; Matsumura, Daiju; Machida, Masahiko; Okumura, Masahiko; Nakamura, Hiroki

Hoshako, 27(6), p.315 - 322, 2014/11

no abstracts in English

Journal Articles

Influence of electron doping on magnetic order in CeRu$$_2$$Al$$_{10}$$

Kobayashi, Riki*; Kaneko, Koji; Saito, Kotaro*; Mignot, J.-M.*; Andr$'e$, G.*; Robert, J.*; Wakimoto, Shuichi; Matsuda, Masaaki*; Chi, S.*; Haga, Yoshinori; et al.

Journal of the Physical Society of Japan, 83(10), p.104707_1 - 104707_5, 2014/10

 Times Cited Count:14 Percentile:68.3(Physics, Multidisciplinary)

Journal Articles

Current-induced enhancement of magnetic anisotropy in spin-charge-coupled multiferroic YbFe$$_{2}$$O$$_{4}$$

Yoshii, Kenji; Matsumura, Daiju; Saito, Hiroyuki; Kambe, Takashi*; Fukunaga, Mamoru*; Muraoka, Yuji*; Ikeda, Naoshi*; Mori, Shigeo*

Journal of the Physical Society of Japan, 83(6), p.063708_1 - 063708_4, 2014/06

 Times Cited Count:4 Percentile:38.77(Physics, Multidisciplinary)

We report the change of magnetic properties of multiferroic YbFe$$_{2}$$O$$_{4}$$, caused by cooling in the presence of an electrical current. The magnetization measured after the cooling becomes smaller by about 10-20% than that after cooling without a current. The current also affects the magnetic anisotropy below about 100 K; the magnetic coercivity is increased by about 10-20%. These phenomena may arise from a coexistence of ferromagnetic and antiferromagnetic domains, or a disturbance in the formation of charge-ordered domains. From the applied viewpoint, the enhancement of anisotropy by an electrical current offers a method for stabilizing magnetization other than the well-known method, i.e., exchange bias.

Journal Articles

Activation detector measurements at the hadron absorber of the NuMI neutrino beamline at Fermilab

Matsuda, Norihiro; Kasugai, Yoshimi; Matsumura, Hiroshi*; Iwase, Hiroshi*; Toyoda, Akihiro*; Yashima, Hiroshi*; Sekimoto, Shun*; Oishi, Koji*; Sakamoto, Yukio*; Nakashima, Hiroshi; et al.

Progress in Nuclear Science and Technology (Internet), 4, p.337 - 340, 2014/04

The Neutrinos at the Main Injector (NuMI) at Fermilab produces intense neutrino beam to investigate the phenomena of the neutrino mixing and oscillation. The Hadron Absorber, consists of thick blocks of aluminum, iron and concrete, is placed at the end of decay volume as a dump for primary proton and secondary particles generated in NuMI. In order to estimate the shielding effect, the reaction rate measurements with activation detector were carried out on the back surface of the absorber. The induced activities in the detectors were measured by analyzing their $$gamma$$-ray spectra using HPGe detectors. Two kind of peak was showed on two-dimensional distributions of obtained reaction rates at right angle to the beam direction. One was strong peaks at the both horizontal side. And, another smaller was at the top. It was concluded that these peaks were the results of particles streaming through the gaps in the Hadron Absorber shielding.

Journal Articles

Magnetic properties of single crystalline YbFe$$_{2}$$O$$_{4}$$

Yoshii, Kenji; Mizumaki, Masaichiro*; Matsumoto, Keisuke*; Mori, Shigeo*; Endo, Naruki; Saito, Hiroyuki; Matsumura, Daiju; Kambe, Takashi*; Ikeda, Naoshi*

Journal of Physics; Conference Series, 428, p.012032_1 - 012032_5, 2013/04

 Times Cited Count:13 Percentile:97.61

We have investigated a single crystal of multiferroic YbFe$$_{2}$$O$$_{4}$$. Its magnetic transition temperature was 250 K. The magnetization along the c-axis was much larger than that within the ab plane, indicating the Ising character of this system. The field-cooled magnetization became negative below 10 K. This was explained in terms of an antiparallel coupling between Yb and Fe moments. Magnetocaloric effects were also observed. The change of entropy was found to show a broad peak with a width of 100 K, which is favorable to application.

Journal Articles

Fitting method for spectrum deduction in high-energy neutron field induced by GeV-protons using experimental reaction-rate data

Kasugai, Yoshimi; Matsuda, Norihiro; Sakamoto, Yukio; Nakashima, Hiroshi; Yashima, Hiroshi*; Matsumura, Hiroshi*; Iwase, Hiroshi*; Hirayama, Hideo*; Mokhov, N.*; Leveling, A.*; et al.

Reactor Dosimetry; 14th International Symposium (ASTM STP 1550), p.675 - 689, 2012/08

Under the collaborative study project of JASMIN, shielding experiments has been carried out using the anti-proton target station (Pbar) of Fermilab. In the experiment, the multi-foil activation technique was utilized, and the neutron spectra in high-energy region between 1 and 100 MeV were deduced by using the "fitting method", which is newly developed. In this method, we made an assumption that neutron energy spectra could be expressed with a simple function. The validity of the fitting method was confirmed by comparison with the results of the unfolding method and the theoretical calculations. Finally, it was found that there are simple correlations between reaction rates and the adjusting parameters in the fitting function. The correlations are useful for estimating the adjusting parameters easily, and a neutron spectrum in the high-energy region can be deduced from a set of reaction-rate data without the complicated calculations of unfolding.

Journal Articles

Shielding experiments under JASMIN collaboration at Fermilab, 4; Measurement and analyses of high-energy neutron spectra in the anti-proton target station

Matsuda, Norihiro; Kasugai, Yoshimi; Sakamoto, Yukio; Nakashima, Hiroshi; Matsumura, Hiroshi*; Iwase, Hiroshi*; Kinoshita, Norikazu*; Hirayama, Hideo*; Yashima, Hiroshi*; Mokhov, N.*; et al.

Journal of the Korean Physical Society, 59(2), p.2055 - 2058, 2011/08

 Times Cited Count:0 Percentile:0(Physics, Multidisciplinary)

It is important to obtain neutron spectra and its intensity on shielding experiment. Deduction of high-energy neutron spectra were done using fitting and unfolding methods based on the shielding data obtained at the anti-proton (pbar) target station in Fermilab. The neutron spectra for fitting method is useful to be easily obtained and the values gave reasonable results compared with nuclear data. Therefore, that for unfolding methods included inconsistency. Furthermore, the deduced neutron spectra were verified through the calculation analyses by PHITS code.

Journal Articles

Magnetic structure determination of Ce$$T_{2}$$Al$$_{10}$$ ($$T$$ = Ru and Os); Single crystal neutron diffraction studies

Kato, Harukazu*; Kobayashi, Riki; Takesaka, Tomoaki*; Nishioka, Takashi*; Matsumura, Masahiro*; Kaneko, Koji; Metoki, Naoto

Journal of the Physical Society of Japan, 80(7), p.073701_1 - 073701_4, 2011/07

 Times Cited Count:57 Percentile:89.98(Physics, Multidisciplinary)

Journal Articles

Measurement of neutron cross sections for yttrium and terbium at 287 MeV

Sekimoto, Shun*; Utsunomiya, Takashi*; Yashima, Hiroshi*; Ninomiya, Kazuhiko*; Omoto, Takashi*; Nakagaki, Reiko*; Shima, Tatsushi*; Takahashi, Naruto*; Shinohara, Atsushi*; Kinoshita, Norikazu*; et al.

Progress in Nuclear Science and Technology (Internet), 1, p.89 - 93, 2011/02

In this work, we tried to determine reaction cross sections for Y and Tb induced by neutrons at 300 MeV, which have never been reported. The irradiations were carried out using neutrons produced through $$^{7}$$Li(p, n) reaction at N0 beam line in the Research Center for Nuclear Physics (RCNP), Osaka University. To estimate quasi-monoenergetic neutron induced cross sections, the target stacks of Y and Tb were irradiated on the two angles of 0 degree and 30 degree for the axis of the primary proton beam. Neutron cross sections were estimated by subtracting the activities produced in the samples placed on 30 degree from those of 0 degree to correct the contribution of the low energy tail in the neutron spectrum.

Journal Articles

Shielding experiments at high energy accelerators of Fermilab, 2; Spatial distribution measurement of reaction rate behind the shield and its application for Moyer model

Yashima, Hiroshi*; Kasugai, Yoshimi; Matsuda, Norihiro; Matsumura, Hiroshi*; Iwase, Hiroshi*; Kinoshita, Norikazu*; Mokhov, N.*; Leveling, A.*; Boehnlein, D.*; Vaziri, K.*; et al.

Progress in Nuclear Science and Technology (Internet), 1, p.48 - 51, 2011/02

The shielding experiment was performed at the anti-proton production target station in Fermi National Accelerator Laboratory. Aluminum, Bismath, Niobium, Copper and Indium samples were placed behind the shields. After irradiation, induced activities of samples were measured by using HPGe detector. The spatial distribution of reaction rate of samples which were placed behind the iron and concrete shields were obtained. The measured data shows that the reaction rates on the outer surfaces of the iron and concrete shields increases toward the downstream of the target. The obtained reaction rates were also fitted to Moyer's formula, and the attenuation lengths for iron and concrete shields were obtained.

Journal Articles

Shielding experiments at high energy accelerators of Fermilab, 4; Calculation analyses

Matsuda, Norihiro; Kasugai, Yoshimi; Matsumura, Hiroshi*; Yashima, Hiroshi*; Iwase, Hiroshi*; Kinoshita, Norikazu*; Sanami, Toshiya*; Mokhov, N.*; Leveling, A.*; Boehnlein, D.*; et al.

Progress in Nuclear Science and Technology (Internet), 1, p.57 - 60, 2011/02

The anti-proton (pbar) production target in Fermi National Accelerator Laboratory can be produced a wide variety of secondary particles including of anti-protons, by bombarding with protons accelerated to 120 GeV. The shielding experimental data, which was obtained around the pbar target, make possible to validate the accuracies of the general-purpose Monte Carlo simulation codes. In this paper, spatial distribution of reaction rates were calculated with two-dimensional (r-z) geometry simplified the real pbar target station using the PHITS, MARS and MCNPX code. These experimental data in iron shield were compared with the calculated data. The comparison for attenuation length of iron were good agreement between the experiments and calculations.

Journal Articles

Experimental studies of shielding and irradiation effects at high energy accelerator facilities

Nakashima, Hiroshi; Sakamoto, Yukio; Iwamoto, Yosuke; Matsuda, Norihiro; Kasugai, Yoshimi; Nakane, Yoshihiro; Masukawa, Fumihiro; Mokhov, N.*; Leveling, A.*; Boehnlein, D.*; et al.

Nuclear Technology, 168(2), p.482 - 486, 2009/11

BB2007-3640.pdf:0.22MB

 Times Cited Count:7 Percentile:48.67(Nuclear Science & Technology)

Experimental studies of shielding and radiation effects have been started using 120-GeV proton synchrotron at Fermi National Accelerator Laboratory (FNAL) under collaboration between FNAL and Japan. The first campaign of the experiment was carried out at the Pbar target station and Numi experimental station at FNAL, using antiproton and neutrino production targets irradiated by 120-GeV protons. The generated secondary particles passing through steel, concrete and rock were measured by activation methods as well as by other detectors such as scintillator with a veto counter, phoswich detector and a Bonner ball counter on trial. Preliminary experimental results are presented.

Journal Articles

Structure of HIV-1 protease in complex with potent inhibitor KNI-272 determined by high-resolution X-ray and neutron crystallography

Adachi, Motoyasu; Ohara, Takashi; Kurihara, Kazuo; Tamada, Taro; Honjo, Eijiro; Okazaki, Nobuo; Arai, Shigeki; Shoyama, Yoshinari; Kimura, Kaname*; Matsumura, Hiroyoshi*; et al.

Proceedings of the National Academy of Sciences of the United States of America, 106(12), p.4641 - 4646, 2009/03

 Times Cited Count:100 Percentile:91.04(Multidisciplinary Sciences)

To further understand the catalytic mechanism and inhibitor recognition of HIV-1 protease, we need to determine the locations of key hydrogen atoms in the catalytic aspartates Asp25 and Asp125. The structure of HIV-1 protease in complex with transition-state analog KNI-272 was determined by combined neutron crystallography at 1.9 ${AA}$ resolution and X-ray crystallography at 1.4 ${AA}$ resolution. The resulting structural data shows that the catalytic residue Asp25 is protonated and that Asp125 is deprotonated. The proton on Asp25 makes a hydrogen bond with the carbonyl group of the allophenylnorstatine group in KNI-272. The deprotonated Asp125 bonds to the hydroxyl proton of Apns. The results provide direct experimental evidence for proposed aspects of the catalytic mechanism of HIV-1 protease; and can therefore contribute substantially to the development of specific inhibitors for therapeutic application.

Journal Articles

A Cu NQR study in a $$d$$-electron heavy-fermion system, CaCu$$_{3}$$Ru$$_{4}$$O$$_{12}$$

Kato, Harukazu*; Tsuruta, Takuya*; Nishioka, Takashi*; Matsumura, Masahiro*; Sakai, Hironori; Kambe, Shinsaku

Journal of Physics and Chemistry of Solids, 68(11), p.2187 - 2190, 2007/11

 Times Cited Count:7 Percentile:37(Chemistry, Multidisciplinary)

Cu nuclear quadrupole resonance (NQR) studies have been carried out for CaCu$$_{3}$$Ru$$_{4}$$O$$_{12}$$,which has been suggested to show a heavy-fermion-like behavioral though it possess no f electron. A Lorentzian shape of the Cu NQR line with a narrow width implies that no magnetic ordering appears, at least, down to 5 K. The spin-lattice relaxation rate of the Cu nuclei probes a change of the Cu 3$$d$$ electron nature, resulting in the Fermi liquid state at a low temperature. These facts strongly support that the heavy fermion picture is available in the concerned compound.

50 (Records 1-20 displayed on this page)