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Journal Articles

Nonmagnetic-magnetic transition and magnetically ordered structure in SmS

Yoshida, Shogo*; Koyama, Takehide*; Yamada, Haruhiko*; Nakai, Yusuke*; Ueda, Koichi*; Mito, Takeshi*; Kitagawa, Kentaro*; Haga, Yoshinori

Physical Review B, 103(15), p.155153_1 - 155153_5, 2021/04

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

Journal Articles

A Consideration on the use of shear waves to improve the sensitivity of an optical ultrasonic sensor for under-sodium viewers

Saruta, Koichi; Shirahama, Takuma*; Yamaguchi, Toshihiko; Ueda, Masashi

E-Journal of Advanced Maintenance (Internet), 10(2), p.1 - 8, 2018/08

Journal Articles

Journal Articles

Magnetic and electronic properties of URu$$_2$$Si$$_2$$ revealed by comparison with nonmagnetic references ThRu$$_2$$Si$$_2$$ and LaRu$$_2$$Si$$_2$$

Emi, Naoya*; Hamabata, Ryosuke*; Nakayama, Daisuke*; Miki, Toshihiro*; Koyama, Takehide*; Ueda, Koichi*; Mito, Takeshi*; Kohori, Yo*; Matsumoto, Yuji*; Haga, Yoshinori; et al.

Journal of the Physical Society of Japan, 84(6), p.063702_1 - 063702_4, 2015/06

 Times Cited Count:10 Percentile:64.05(Physics, Multidisciplinary)

Journal Articles

Observation of the partial Fermi surface quenching in the noncentrosymmetric superconductor Mo$$_3$$Al$$_2$$C

Koyama, Takehide*; Ozaki, Yuzuru*; Ueda, Koichi*; Mito, Takeshi*; Kohara, Takao*; Waki, Takeshi*; Tabata, Yoshikazu*; Michioka, Chishiro*; Yoshimura, Kazuyoshi*; Suzuki, Michito; et al.

Journal of the Physical Society of Japan, 81(Suppl.B), p.SB008_1 - SB008_5, 2012/12

 Times Cited Count:1 Percentile:11.71(Physics, Multidisciplinary)

The normal state properties of a noncentrosymmetric superconductor Mo$$_3$$Al$$_2$$C are studied by means of the nuclear magnetic resonance (NMR) experiment. The change of NMR line shape and the peak of the nuclear spin-echo decay rate at $$simeq$$ 130 K indicate that the Mo$$_3$$Al$$_2$$C exhibits the phase transition prior to the emergence of superconductivity. The reduction in the conduction electron density is inferred from the decrease in the nuclear spin-lattice relaxation rate. The nature of the newly found phase transition is discussed by considering the result of the first principle calculations, indicating a good nesting property of the Fermi surfaces.

Journal Articles

Partial gap opening on the Fermi surface of the noncentrosymmetric superconductor Mo$$_3$$Al$$_2$$C

Koyama, Takehide*; Ozaki, Yuzuru*; Ueda, Koichi*; Mito, Takeshi*; Kohara, Takao*; Waki, Tsuyoshi*; Tabata, Yoshikazu*; Michioka, Chishiro*; Yoshimura, Kazuyoshi*; Suzuki, Michito; et al.

Physical Review B, 84(21), p.212501_1 - 212501_4, 2011/12

 Times Cited Count:9 Percentile:42.37(Materials Science, Multidisciplinary)

The results of $$^{27}$$Al nuclear magnetic resonance and specific-heat measurements of the noncentrosymmetric superconductor Mo$$_3$$Al$$_2$$C are reported. The phase transition around 130 K is inferred from a distinct change in the NMR spectrum, a clear peak in the spin-echo decay rate, and an anomaly in the specific heat. Possibility of charge-density wave ordering around 130 K is discussed by calculating the Fermi surfaces in the normal states and considering the partial quenching of the Fermi surfaces with the decrease in 1/$$T$$$$_1$$ below the superconducting transition temperature.

Journal Articles

Conduction-band electronic states of YbInCu$$_4$$ studied by photoemission and soft X-ray absorption spectroscopies

Utsumi, Yuki*; Sato, Hitoshi*; Kurihara, Hidenao*; Maso, Hiroyuki*; Hiraoka, Koichi*; Kojima, Kenichi*; Tobimatsu, Komei*; Okochi, Takuo*; Fujimori, Shinichi; Takeda, Yukiharu; et al.

Physical Review B, 84(11), p.115143_1 - 115143_7, 2011/09

 Times Cited Count:7 Percentile:31.79(Materials Science, Multidisciplinary)

We have studied conduction-band (CB) electronic states of a typical valence-transition compound YbInCu$$_4$$ by means of temperature-dependent hard X-ray photoemission spectroscopy (HX-PES), soft X-ray absorption spectroscopy (XAS), and soft X-ray photoemission spectroscopy (SX-PES) of the valence band. We have described the valence transition in YbInCu$$_4$$ in terms of the charge transfer from the CB to Yb 4$$f$$ states.

Journal Articles

Development of an ISI robot for the fast breeder reactor MONJU primary heat transfer system piping

Tagawa, Akihiro; Ueda, Masashi; Yamashita, Takuya; Narisawa, Masataka*; Haga, Koichi*

Journal of Nuclear Science and Technology, 48(4), p.504 - 509, 2011/04

This paper describes the development of a new inspection robot for the in-service inspection of the heat transfer system of the fast breeder reactor MONJU. The inspection was carried out using a tire-type ultrasonic sensor for volumetric tests at high temperature (atmosphere, 55 $$^{circ}$$C; piping surface, 80 $$^{circ}$$C) and radiation exposure condition (dose rate, 10 mGy/h; piping surface dose rate, 15 mGy/h). An inspection robot using a new tire type for the ultrasonic testing sensor and a new control method was developed. A signal-to-noise ratio S/N over 2 was obtained during the functional test for a calibration defect with a depth of 50%t (from the tube wall thickness). In the automatic inspection test, an EDM slit with a depth of 9% from the pipe thickness was detectable and with an S/N ratio = 4.0 (12.0 dB).

Journal Articles

Effect of water distributions on performances of JARI standard PEFC by using neutron radiography

Murakawa, Hideki*; Ueda, Tadanobu*; Yoshida, Takehisa*; Sugimoto, Katsumi*; Asano, Hitoshi*; Takenaka, Nobuyuki*; Mochiki, Koichi*; Iikura, Hiroshi; Yasuda, Ryo; Matsubayashi, Masahito

Nuclear Instruments and Methods in Physics Research A, 605(1-2), p.127 - 130, 2009/06

 Times Cited Count:22 Percentile:83.4(Instruments & Instrumentation)

Journal Articles

Controlling the phase matching conditions of optical parametric chirped-pulse amplification using partially deuterated KDP

Ogawa, Kanade; Sueda, Keiichi*; Akahane, Yutaka; Aoyama, Makoto; Tsuji, Koichi; Fujioka, Kana*; Kanabe, Tadashi*; Yamakawa, Koichi; Miyanaga, Noriaki*

Optics Express (Internet), 17(10), p.7744 - 7749, 2009/05

 Times Cited Count:12 Percentile:54.45(Optics)

Using a partially deuterated KDP crystal for an optical parametric amplifier, we demonstrated ultrabroadband optical parametric chirped-pulse amplification of more than 250 nm bandwidth at a center wavelength of 1050 nm. We numerically show how to control the broadband phase matching conditions at different wavelengths to match center wavelengths of suitable broadband seed sources by adjusting the deuteration level in partially deuterated KDP.

Journal Articles

Spectroscopic characterization of ultrashort laser driven targets incorporating both Boltzmann and particle-in-cell models

Sherrill, M. E.*; Abdallah, J.*; Csanak, G.*; Dodd, E. S.*; Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki*; Yamakawa, Koichi; et al.

High-Power Laser Ablation VII (Proceedings of SPIE Vol.7005), p.70051R_1 - 70051R_11, 2008/06

Journal Articles

Spin-lattice instability to a fractional magnetization state in the spinel HgCr$$_{2}$$O$$_{4}$$

Matsuda, Masaaki; Ueda, Hiroaki*; Kikkawa, Akiko*; Tanaka, Yoshikazu*; Katsumata, Koichi*; Narumi, Yasuo*; Inami, Toshiya; Ueda, Yutaka*; Lee, S.-H.*

Nature Physics, 3(6), p.397 - 400, 2007/06

 Times Cited Count:92 Percentile:93.17(Physics, Multidisciplinary)

Cr-CrCr-based spinel compounds ACr$$_{2}$$O$$_{4}$$ (A=Mg, Zn, Cd, and Hg) are so far the best model systems for a network of corner-sharing tetrahedrons with isotropic nearest-neighbor antiferromagnetic interactions. The systems exhibit novel spin-Peierls phase transitions from cubic spin liquid to non-cubic N$'e$el states at low temperatures. Recent bulk magnetization studies on CdCr$$_{2}$$O$$_{4}$$ and HgCr$$_{2}$$O$$_{4}$$ revealed the magnetic field-induced half magnetization plateau states that are stable over a wide range of field. Recent bulk magnetization studies on CdCr$$_{2}$$O$$_{4}$$ and HgCr$$_{2}$$O$$_{4}$$ revealed the magnetic field-induced half magnetization plateau states that are stable over a wide range of field.

Journal Articles

Pressure effect of electrical resistivity and AC specific heat in CePtAl

Nakashima, Miho*; Ueda, Taiki*; Shimizu, Katsuya*; Nakashima, Hiroshi*; Thamizhavel, A.*; Tateiwa, Naoyuki; Haga, Yoshinori; Hedo, Masato*; Uwatoko, Yoshiya*; Settai, Rikio*; et al.

Journal of Magnetism and Magnetic Materials, 310(2, Part1), p.e9 - e11, 2007/03

We measured the electrical resistivity and AC-specific heat for a canted ferromagnet CePtAl under pressures using a diamond-anvilpressure cell. With increasing pressure, the magnetic ordering temperature $$T_{rm C1}$$ increases monotonously, becomes constant above 8 GPa and then starts to decrease steeply in a narrow pressure region from 10.3 to 10.9 GPa, indicating the first-order like phase transition. The similar pressure dependence of $$T_{rm C1}$$ was obtained in the AC-specific heat measurement.

Journal Articles

Spectroscopic characterization of an ultrashort-pulse-laser-driven Ar cluster target incorporating both Boltzmann and particle-in-cell models

Sherrill, M. E.*; Abdallah, J. Jr.*; Csanak, G.*; Dodd, E. S.*; Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki*; Yamakawa, Koichi; et al.

Physical Review E, 73(6), p.066404_1 - 066404_6, 2006/06

 Times Cited Count:29 Percentile:77.97(Physics, Fluids & Plasmas)

A model that solves simultaneously both the electron and atomic kinetics was used to generate synthetic He$$_alpha$$ X-ray spectra to characterize a high intensity ultrashort laser driven Ar cluster target experiment. In particular, level populations were obtained from a detailed collisional-radiative model where collisional rates were computed from a time varying electron distribution function obtained from the solution of the zero dimensional Boltzmann equation. In addition, aparticle-in-cell simulation was used to model the laser interaction with the cluster target and provided the initial electron energy distribution function (EEDF) for the Boltzmann solver. This study suggests that the high density plasma contribution to the time-integrated He$$_alpha$$ spectrum was in a highly non-equilibrium state in both the EEDF and the ion level populations and provides a prediction of 5.7 ps for the average cluster integrity time for this high density state.

Journal Articles

Coupled electron and atomic kinetics through the solution of the Boltzmann equation for generating time-dependent X-ray spectra

Sherrill, M. E.*; Abdallah, J. Jr.*; Csanak, G.*; Kilcrease, D. P.*; Dodd, E. S.*; Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; et al.

Journal of Quantitative Spectroscopy & Radiative Transfer, 99(1-3), p.584 - 594, 2006/05

 Times Cited Count:2 Percentile:13.72(Optics)

In this work, we present a model that solves self-consistently the electron and atomic kinetics to characterize highly non-equilibrium plasmas, in particular for those systems where both the electron distribution function is far from Maxwellian and the evolution of the ion level populations are dominated by time dependent atomic kinetics. In this model, level populations are obtained from a detailed collisional-radiative model where collision rates are computed from a time varying electron distribution function obtained from the solution of the zero-dimensional Boltzmann equation. The Boltzmann collision term includes the effects of electron-electron collisions, electron collisional ionization, excitation and de-excitation. An application for He$$_alpha$$ spectra from a short pulse laser irradiated argon cluster target will be shown to illustrate the results of our model.

Journal Articles

Selective transition to the closely-lying states Cs(7$$D$$$$_{3/2}$$) and Cs(7$$D$$$$_{5/2}$$) by femtosecond laser pulses

Yamada, Hidetaka; Yokoyama, Keiichi; Teranishi, Yoshiaki*; Sugita, Akihiro; Shirai, Toshizo*; Aoyama, Makoto; Akahane, Yutaka; Inoue, Norihiro*; Ueda, Hideki*; Yamakawa, Koichi; et al.

Physical Review A, 72(6), p.063404_1 - 063404_5, 2005/12

 Times Cited Count:6 Percentile:32.38(Optics)

A demonstration of coherent quantum control for ultrafast precise selection of closely-lying states is reported. A phase-locked pair of femtosecond laser pulses is generated through a pulse shaper to excite the ground-state cesium atom to the Cs(7$$D$$$$_{3/2}$$) and Cs(7$$D$$$$_{5/2}$$) states by two-photon absorption. The excited state population is measured by detecting fluorescence from each spin-orbit state. By controlling the phase-difference of the pulse pair, an ultrafast precise selection is accomplished. The contrast ratio of the maximal to minimal selection ratio exceeds 10$$^3$$ with the delay less than 400 fs.

Journal Articles

Magnetic property and pressure effect of a single crystal CeRhGe

Ueda, Taiki*; Honda, Daisuke*; Shiromoto, Tomoyuki*; Metoki, Naoto; Honda, Fuminori*; Kaneko, Koji; Haga, Yoshinori; Matsuda, Tatsuma; Takeuchi, Tetsuya*; Thamizhavel, A.*; et al.

Journal of the Physical Society of Japan, 74(10), p.2836 - 2842, 2005/10

 Times Cited Count:14 Percentile:62.24(Physics, Multidisciplinary)

JAEA Reports

Studies on Data Base Management for Nuclide Migration and Improvement of Individual Models (II) (Summary)

Tsujimoto, Keiichi*; Miura, Fusae*; Morooka, Koichi*; Ueda, Shinzo*

JNC TJ8400 2004-021, 75 Pages, 2005/02

JNC-TJ8400-2004-021.pdf:1.31MB

Methods of management of database which was based on understanding of phenomena, reliable, and closely related with performance assessment were studied on parallel with researches for individual model improvement by means of literature survey, column experiment, and analysis code development.For future management of JNC-TDB was discussed with the latest literatures. Collaboration with outer organization was considered necessary especially on authorization of the TDB. One of the outer organizations could be found in geo-thermal research field.For future management of JNC-SDB, sorption ithotherm of Np on bentonite was tested, and the consistency of the data in SDB was found. A semi-quantitative evaluation method of the reliability of the data was developed and tested with the sorption of Pu and Ni on bentonite. The result shows moderateness of the method and some literature data was considered unreliable by the evaluation.From the literature survey of ir/reversibility of nuclide sorption on colloid showed that apparent irreversibility may often be caused by slow kinetics. Additionally, some general recommendation on the system to be studied was discussed.The column experiment of Sr migration facilitated by colloid through porous media was carried out and analysed by COLFRAC-MRL code. The code was developed to simulate the colloid facilitated migration through porous media.

JAEA Reports

Studies on Data Base Management for Nuclide Migration and Improvement of Individual Models (II)

Tsujimoto, Keiichi*; Miura, Fusae*; Morooka, Koichi*; Ueda, Shinzo*

JNC TJ8400 2004-020, 294 Pages, 2005/02

JNC-TJ8400-2004-020.pdf:3.96MB

Methods of management of database which was based on understanding of phenomena, reliable, and closely related with performance assessment were studied on parallel with researches for individual model improvement by means of column experiment, and analysis code development for colloids.For nuclide transport database, the basic data development method was examined in order to improve the credibility of the data stored in the database.For the analysis and code development for colloid transport, user interface of the colloid transport analysis code, COLFRAC-MRL code, that was developed in the last year, was developed. The dose analysis based on the nuclide transport analysis with considering colloids are executed by using COLFRAC-MRL code. The effect of chemical equilibrium and kinetics model for nuclide sorption on colloids are evaluated in the analysis.The standard measurement method was examined and data was obtained by the experiments for distribution coefficient of nuclide and colloids, which is the important parameter for safety performance assessment of high-level radioactive waste.

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