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Zhang, Z.*; Hattori, Takanori; Song, R.*; Yu, D.*; Mole, R.*; Chen, J.*; He, L.*; Zhang, Z.*; Li, B.*
Journal of Applied Physics, 136(3), p.035105_1 - 035105_8, 2024/07
Times Cited Count:2 Percentile:35.22(Physics, Applied)Solid-state refrigeration using barocaloric materials is environmentally friendly and highly efficient, making it a subject of global interest over the past decade. Here, we report giant barocaloric effects in sodium hexafluorophosphate (NaPF) and sodium hexafluoroarsenate (NaAsF
) that both undergo a cubic-to-rhombohedral phase transition near room temperature. We have determined that the low-temperature phase structure of NaPF
is a rhombohedral structure with space group R
and NaAsF
, i.e., F
, E
, and A
. The phase transition temperature varies with pressure at a rate of dT
/dP = 250 and 310 K/GPa for NaPF
and NaAsF
. The pressure-induced entropy changes of NaPF
and NaAsF
are determined to be around 45.2 and 35.6J kg
K
, respectively. The saturation driving pressure is about 40 MPa. The pressure-dependent neutron powder diffraction suggests that the barocaloric effects are related to the pressure-induced cubic-to-rhombohedral phase transitions.
Watabe, Hiroshi*; Sato, Tatsuhiko; Yu, K. N.*; Zivkovic, M.*; Krstic, D.*; Nikezic, D.*; Kim, K. M.*; Yamaya, Taiga*; Kawachi, Naoki*; Tanaka, Hiroki*; et al.
Radiation Protection Dosimetry, 200(2), p.130 - 142, 2024/02
Times Cited Count:2 Percentile:43.92(Environmental Sciences)Previously, we have developed DynamicMC for modelling relative movement of ORNL phantom in a radiation field for MCNP. Using this software, 3-dimensional dose distributions in a phantom irradiated by a certain mono-energetic source can be deduced through its graphical user interface (GUI). In this study, we extended DynamicMC to be used in combination with the PHITS by providing it with a higher flexibility for dynamic movement for a less sophisticated anthropomorphic phantom. We anticipate that the present work and the developed open-source tools will be in the interest of nuclear radiation physics community for research and teaching purposes.
Shangguan, Y.*; Bao, S.*; Dong, Z.-Y.*; Xi, N.*; Gao, Y.-P.*; Ma, Z.*; Wang, W.*; Qi, Z.*; Zhang, S.*; Huang, Z.*; et al.
Nature Physics, 19(12), p.1883 - 1889, 2023/09
Times Cited Count:19 Percentile:93.50(Physics, Multidisciplinary)Jiang, X.*; Hattori, Takanori; Xu, X.*; Li, M.*; Yu, C.*; Yu, D.*; Mole, R.*; Yano, Shinichiro*; Chen, J.*; He, L.*; et al.
Materials Horizons, 10(3), p.977 - 982, 2023/03
Times Cited Count:26 Percentile:93.14(Chemistry, Multidisciplinary)As a promising environment-friendly alternative to current vapor-compression refrigeration, solid-state refrigeration based on the barocaloric effect has been attracting world wide attention. Generally, both phases in which a barocaloric effect occurs are present at ambient pressure. Here, instead, we demonstrate that KPF exhibits a colossal barocaloric effect due to the creation of a high-pressure rhombohedral phase. The phase diagram is constructed based on pressure-dependent calorimetric, Raman scattering, and neutron diffraction measurements. The present study is expected to provide an alternative routine to colossal barocaloric effects through the creation of a high-pressure phase.
Sheng, J.*; Wang, L.*; Candini, A.*; Jiang, W.*; Huang, L.*; Xi, B.*; Zhao, J.*; Ge, H.*; Zhao, N.*; Fu, Y.*; et al.
Proceedings of the National Academy of Sciences of the United States of America, 119(51), p.e2211193119_1 - e2211193119_9, 2022/12
Times Cited Count:34 Percentile:93.63(Multidisciplinary Sciences)Yun, D.*; Chae, H.*; Lee, T.*; Lee, D.-H.*; Ryu, H. J.*; Banerjee, R.*; Harjo, S.; Kawasaki, Takuro; Lee, S. Y.*
Journal of Alloys and Compounds, 918, p.165673_1 - 165673_7, 2022/10
Times Cited Count:14 Percentile:65.57(Chemistry, Physical)Takagi, Rina*; Matsuyama, Naofumi*; Ukleev, V.*; Yu, L.*; White, J. S.*; Francoual, S.*; Mardegan, J. R. L.*; Hayami, Satoru*; Saito, Hiraku*; Kaneko, Koji; et al.
Nature Communications (Internet), 13, p.1472_1 - 1472_7, 2022/03
Times Cited Count:114 Percentile:99.58(Multidisciplinary Sciences)Fujihara, Masayoshi*; Morita, Katsuhiro*; Mole, R.*; Mitsuda, Setsuo*; Toyama, Takami*; Yano, Shinichiro*; Yu, D.*; Sota, Shigetoshi*; Kuwai, Tomohiko*; Koda, Akihiro*; et al.
Nature Communications (Internet), 11, p.3429_1 - 3429_7, 2020/07
Times Cited Count:52 Percentile:92.32(Multidisciplinary Sciences)Li, B.*; Kawakita, Yukinobu; Kawamura, Seiko; Sugahara, Takeshi*; Wang, H.*; Wang, J.*; Chen, Y.*; Kawaguchi, Saori*; Kawaguchi, Shogo*; Ohara, Koji*; et al.
Nature, 567(7749), p.506 - 510, 2019/03
Times Cited Count:327 Percentile:99.52(Multidisciplinary Sciences)Refrigeration is of vital importance for modern society for example, for food storage and air conditioning- and 25 to 30% of the world's electricity is consumed for refrigeration. Current refrigeration technology mostly involves the conventional vapour compression cycle, but the materials used in this technology are of growing environmental concern because of their large global warming potential. As a promising alternative, refrigeration technologies based on solid-state caloric effects have been attracting attention in recent decades. However, their application is restricted by the limited performance of current caloric materials, owing to small isothermal entropy changes and large driving magnetic fields. Here we report colossal barocaloric effects (CBCEs) (barocaloric effects are cooling effects of pressure-induced phase transitions) in a class of disordered solids called plastic crystals. The obtained entropy changes in a representative plastic crystal, neopentylglycol, are about 389 joules per kilogram per kelvin near room temperature. Pressure-dependent neutron scattering measurements reveal that CBCEs in plastic crystals can be attributed to the combination of extensive molecular orientational disorder, giant compressibility and highly anharmonic lattice dynamics of these materials. Our study establishes the microscopic mechanism of CBCEs in plastic crystals and paves the way to next-generation solid-state refrigeration technologies.
Li, B.; Wang, H.*; Kawakita, Yukinobu; Zhang, Q.*; Feygenson, M.*; Yu, H. L.*; Wu, D.*; Ohara, Koji*; Kikuchi, Tatsuya*; Shibata, Kaoru; et al.
Nature Materials, 17(3), p.226 - 230, 2018/03
Times Cited Count:161 Percentile:97.18(Chemistry, Physical)Yu, R.*; Hojo, Hajime*; Watanuki, Tetsu; Mizumaki, Masaichiro*; Mizokawa, Takashi*; Oka, Kengo*; Kim, H.*; Machida, Akihiko; Sakaki, Koji*; Nakamura, Yumiko*; et al.
Journal of the American Chemical Society, 137(39), p.12719 - 12728, 2015/10
Times Cited Count:40 Percentile:72.17(Chemistry, Multidisciplinary)no abstracts in English
Yu, R.*; Hojo, Hajime*; Oka, Kengo*; Watanuki, Tetsu; Machida, Akihiko; Shimizu, Keisuke*; Nakano, Kiho*; Azuma, Masaki*
Chemistry of Materials, 27(6), p.2012 - 2017, 2015/03
Times Cited Count:27 Percentile:60.58(Chemistry, Physical)no abstracts in English
Yu, Q.*; Qi, L.*; Tsuru, Tomohito; Traylor, R.*; Rugg, D.*; Morris, J. W. Jr.*; Asta, M.*; Chrzan, D. C.*; Minor, A. M.*
Science, 347(6222), p.635 - 639, 2015/02
Times Cited Count:288 Percentile:98.60(Multidisciplinary Sciences)Given that solute atoms interact weakly with the long-range elastic fields of screw dislocations, it has long been accepted that solution hardening is only marginally effective in materials with mobile screw dislocations. This accepted wisdom has recently been questioned by first-principles calculations suggesting that solutes may interact much more strongly with the screw dislocation core. We report here the results of a combined experimental and computational study undertaken to elucidate the profound hardening effect of oxygen in pure hexagonally-close-packed structured -Ti. High resolution and in situ transmission electron microscopy nanomechanical characterization establish that the strengthening is due to the strong interaction between oxygen and the core of screw dislocations that mainly glide on prismatic planes. First-principles calculations of the screw dislocation core reveal a simple crystallographic source for the oxygen-dislocation interaction that is consistent with experimental observations. The distortion of the interstitial sites at the dislocation core creates a very strong but short-range repulsion for oxygen atoms. These mechanisms effectively pin the dislocation near the oxygen interstitial. These results establish a highly effective mechanism for strengthening by interstitial solutes that, contrary to prior understanding, may be significant in many structural alloys.
Sako, Hiroyuki; Ahn, J. K.*; Baek, K. H.*; Bassalleck, B.*; Fujioka, H.*; Guo, L.*; Hasegawa, Shoichi; Hicks, K.*; Honda, R.*; Hwang, S. H.*; et al.
Journal of Instrumentation (Internet), 9(4), p.C04009_1 - C04009_10, 2014/04
Times Cited Count:3 Percentile:14.89(Instruments & Instrumentation)A TPC has been developed for J-PARC E42 experiment to search for H-dibaryon in (,
) reaction. An event with 2
and 2 protons decaying from H-dibaryon is searched for inside the TPC. The TPC has octagonal prism shape drift volume with about 50 cm diameter with 55 cm drift length filled with Ar-CH
(90:10) gas. At the end of the drift volume, 3-layer GEMs are equipped. In order to analyze momenta of produced particles, the TPC is applied with 1 T dipole magnetic field parallel to the drift electric field with a superconducting Helmholz magnet. In order to maximize the acceptance of H-dibaryon events, a diamond target is installed inside the TPC drift volume, in a cylindrical hole opened from the top to the middle of the drift volume. Since extremely high-rate
beam is directly injected into the TPC drift volume to the target, a gating grid and GEMs are adopted to suppress positive-ion feedback.
Deng, Z.*; Zhao, K.*; Gu, B.; Han, W.*; Zhu, J. L.*; Wang, X. C.*; Li, X.*; Liu, Q. Q.*; Yu, R. C.*; Goko, Tatsuo*; et al.
Physical Review B, 88(8), p.081203_1 - 081203_5, 2013/08
Times Cited Count:77 Percentile:91.56(Materials Science, Multidisciplinary)Vostner, A.*; Pong, I.*; Bessette, D.*; Devred, A.*; Sgobba, S.*; Jung, A.*; Weiss, K.-P.*; Jewell, M. C.*; Liu, S.*; Yu, W.*; et al.
IEEE Transactions on Applied Superconductivity, 23(3), p.9500705_1 - 9500705_5, 2013/06
Times Cited Count:13 Percentile:53.56(Engineering, Electrical & Electronic)The ITER Cable-In-Conduit Conductor (CICC) used in the superconducting magnet system consists of a cable made of 300 to 1440 strands housed in a stainless steel tube (a.k.a. jacket or conduit). There are circular, square, as well as circle-in-square jackets, made of either a very low carbon AISI 316LN grade stainless steel or a high Mn austenitic stainless steel developed for ITER called JK2LB. Selected mechanical properties of the base material and weld joint were tested at room temperature and/or cryogenic temperatures ( 7 K). The Domestic Agencies (DAs) reference laboratories and the ITER-IO appointed reference laboratories, CERN and Karlsruhe Institute of Technology (KIT) performed mechanical tests. This paper will compare the test results (e.g. elongation to failure) from different laboratories.
Bruzzone, P.*; Stepanov, B.*; Wesche, R.*; Mitchell, N.*; Devred, A.*; Nunoya, Yoshihiko; Tronza, V.*; Kim, K.*; Boutboul, T.*; Martovetsky, N.*; et al.
Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 8 Pages, 2013/03
Starting March 2007, over 60 ITER cable-in-conduit conductors (CICC) have been tested in the SULTAN test facility, Switzerland. For the NbTi CICC, the results confirm the prediction from the strand data, which are made taking the peak field over the conductor cross section as operating field. All the NbTi samples passed the supplier qualification phase. For the NbSn CICC, the performance prediction is not straightforward because of the irreversible degradation caused by filament damage occurring during cyclic loading. At the first run of the test campaign, the performance of all the Nb
Sn samples largely meets the target for all the tested samples. Contrary to the NbTi CICC case, the n-index of the transition is substantially lower than in the strands, providing evidence of irreversible degradation. The performance loss upon load cycles and thermal cycles has a broad range among the various conductor samples.
Yu, R. S.*; Maekawa, Masaki; Kawasuso, Atsuo; Wang, B. Y.*; Wei, L.*
Nuclear Instruments and Methods in Physics Research B, 270, p.47 - 49, 2012/01
Times Cited Count:9 Percentile:54.18(Instruments & Instrumentation)Deng, Z.*; Jin, C. Q.*; Liu, Q. Q.*; Wang, X. C.*; Zhu, J. L.*; Feng, S. M.*; Chen, L. C.*; Yu, R. C.*; Arguello, C.*; Goko, Tatsuo*; et al.
Nature Communications (Internet), 2, p.1425_1 - 1425_5, 2011/08
Times Cited Count:172 Percentile:93.60(Multidisciplinary Sciences)In a prototypical ferromagnet (Ga,Mn)As based on a III-V semiconductor, substitution of divalent Mn atoms into trivalent Ga sites leads to severely limited chemical solubility and metastable specimens available only as thin films. The doping of hole carriers via (Ga,Mn) substitution also prohibits electron doping. To overcome these difficulties, Masek et al. theoretically proposed systems based on a I-II-V semiconductor LiZnAs, where isovalent (Zn,Mn) substitution is decoupled from carrier doping with excess/deficient Li concentrations. Here we show successful synthesis of Li(Zn
Mn
)As in bulk materials. We reported that ferromagnetism with a critical temperature of up to 50 K is observed in nominally Li-excess compounds, which have p-type carriers.
Yu, R. S.*; Maekawa, Masaki; Kawasuso, Atsuo; Sekiguchi, Takashi*; Wang, B. Y.*; Qin, X. B.*; Wang, Q. Z.*
Nuclear Instruments and Methods in Physics Research B, 267(18), p.3097 - 3099, 2009/09
Times Cited Count:3 Percentile:27.49(Instruments & Instrumentation)The structural evolution of silicon oxide films with Germanium implantation was traced with a positron beam equipped with positron annihilation Doppler broadening and lifetime spectrometers. Results indicate that the film structure change as a function of the annealing temperature could be divided into four stages: (I) T 300
C; (II) 300
C
T
500
C; (III) 600
C
T
800
C; (IV) T
900
C. In comparison with stage I, the increased positron annihilation Doppler broadening S values during stage II is ascribed to the annealing out of point defects and coalescence of intrinsic open volumes in silicon oxides. The obtained long positron lifetime and high S values without much fluctuation in stage III suggest a rather stable film structure. Further annealing above 900
C brings about dramatic change of the film structure with Ge precipitation. Positron annihilation spectroscopy is thereby a sensitive probe for the diagnosis of microstructure variation of silicon oxide thin films with nano-precipitation.