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Shimizu, Kazuyuki*; Toda, Hiroyuki*; Fujihara, Hiro*; Yamaguchi, Masatake; Uesugi, Masayuki*; Takeuchi, Akihisa*; Nishijima, Masahiko*; Kamada, Yasuhiro*
Corrosion, 79(8), p.818 - 830, 2023/08
7xxx aluminum alloys are representative high-strength aluminum alloys; however, mechanical property degradation due to hydrogen hinders further strengthening. We propose the dispersion of Mn-based second-phase particles as a novel technique for preventing 7xxx aluminum alloy hydrogen embrittlement. In this study, the deformation and fracture behaviors of high hydrogen 7xxx alloys containing 0.0% Mn and 0.6% Mn are observed in situ using synchrotron radiation X-ray tomography. The obtained macroscopic hydrogen embrittlement is quantitatively analyzed based on hydrogen partitioning in alloys. Adding 0.6% Mn, generating second-phase particles with high hydrogen trapping abilities, significantly suppresses hydrogen-induced quasicleavage fracture.
Nii, Keisuke*; Ida, Yoshiaki*; Ueda, Hideki*; Yamaguchi, Takanori*; Kabumoto, Hiroshi; Kamiya, Junichiro; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; et al.
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.601 - 604, 2023/01
no abstracts in English
Nii, Keisuke*; Ida, Yoshiaki*; Ueda, Hideki*; Yamaguchi, Takanori*; Kabumoto, Hiroshi; Kamiya, Junichiro; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; et al.
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.334 - 337, 2021/10
no abstracts in English
Yamaguchi, Yasuhiro; Garc
a-Tecocoatzi, H.*; Giachino, A.*; Hosaka, Atsushi; Santopinto, E.*; Takeuchi, Sachiko*; Takizawa, Makoto*
Few-Body Systems, 62(3), p.33_1 - 33_7, 2021/09
Times Cited Count：0 Percentile：0(Physics, Multidisciplinary)We investigate the hidden-charm pentaquarks as hadronic molecules of 
and 
coupled to a 
compact core by employing an interaction satisfying the heavy quark and chiral symmetries. Our model can consistently explain the masses and decay widths of 
, 
and 
with spin parity assignments 
, 
and 
, respectively. We find that the mass ordering is dominantly determined by the short-range interaction given by coupling to the compact core, while the decay widths by the tensor force of the one-pion exchange.
pentaquarks in hadron dynamicsYamaguchi, Yasuhiro
Genshikaku Kenkyu, 65(2), p.19 - 30, 2021/03
Recently exotic hadrons including a 
component have been reported in experimental researches. The exotic states cannot be explained by the ordinary hadron picture, namely a baryon as a three-quark state, and a meson as a quark-antiquark state, while a multiquark component would be dominated in their structure. We investigate the pentaquarks reported by LHCb as a 
hadronic molecule coupling to a 
compact core. The coupling to the core plays an short-range interaction (
potential) generating an attraction. In addition, the one pion exchange potential (OPEP) as a long-range interaction is introduced. Our model can consistently explain the masses and widths of the states reported by LHCb in 2019. The role of the interactions employed is investigated, and we find that the structure of the energy level is determined by the potential, while the decay width by the tensor term of the OPEP.
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：30 Percentile：96.39(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Yamaguchi, Yasuhiro; Yamanaka, Nodoka*
Physical Review D, 103(1), p.013001_1 - 013001_20, 2021/01
Times Cited Count：24 Percentile：94.24(Astronomy & Astrophysics)We evaluate the electric dipole moment (EDM) of charged leptons in the standard model. We first prove that, at the quark-gluon level, it is suppressed due to the GIM mechanism. We then calculate the hadronic long distance contribution generated by vector mesons at one-loop level. The 
= 1 weak hadronic interaction is derived using the factorization, and the strong interaction is modeled by the hidden local symmetry framework. We find that the EDMs of charged leptons obtained from this hadronic mechanism are much larger than the perturbative four-loop level quark-gluon process, by several orders of magnitude.
Yamaguchi, Yasuhiro; Yamanaka, Nodoka*
Physical Review Letters, 125(24), p.241802_1 - 241802_7, 2020/12
Times Cited Count：22 Percentile：86.48(Physics, Multidisciplinary)We reevaluate the electric dipole moment (EDM) of charged leptons in the standard model using hadron effective models. We find unexpectedly large EDM generated by the hadron level long-distance effect, 
, 
, and 
cm, with an error bar of 70%, exceeding the conventionally known four-loop level elementary contribution by several orders of magnitude.
within the Regge-plus-resonance modelSkoupil, D.*; Yamaguchi, Yasuhiro
Physical Review D, 102(7), p.074009_1 - 074009_19, 2020/10
Times Cited Count：1 Percentile：9.34(Astronomy & Astrophysics)
-meson photoproduction off the proton is studied, which will be useful tool to investigate the charmed-hadron properties. Since many parameters are still unknown in the charmed-hadron photoproduction, we employ the Regge-plus-resonance model, where there are limited number of parameters needed to be adjusted. The background part is modeled within the Regge model with the 
trajectories being exchanged in the 
channel or 
trajectories in the 
channel. These contributions create the cross sections which are smooth functions of energies. We also introduce the exchange of the hidden-pentaquarks in the 
channel that create the sharp peak in the cross section predictions.
pentaquarks with chiral tensor and quark dynamicsYamaguchi, Yasuhiro; Garca-Tecocoatzi, H.*; Giachino, A.*; Hosaka, Atsushi; Santopinto, E.*; Takeuchi, Sachiko*; Takizawa, Makoto*
Physical Review D, 101(9), p.091502_1 - 091502_7, 2020/05
Times Cited Count：37 Percentile：94.23(Astronomy & Astrophysics)We investigate the hidden-charm pentaquarks as hadronic molecules of and coupled to a compact core by employing an interaction satisfying the heavy quark and chiral symmetries. Our model can consistently explain the masses and decay widths of , and with spin parity assignments , and , respectively. We find that the mass ordering is dominantly determined by the short-range interaction given by coupling to the compact core, while the decay widths by the tensor force of the one-pion exchange.
ladderUeda, Hiroshi*; Onoda, Shigeki*; Yamaguchi, Yasuhiro*; Kimura, Tsuyoshi*; Yoshizawa, Daichi*; Morioka, Toshiaki*; Hagiwara, Masayuki*; Hagihara, Masato*; Soda, Minoru*; Masuda, Takatsugu*; et al.
Physical Review B, 101(14), p.140408_1 - 140408_6, 2020/04
Times Cited Count：3 Percentile：22.67(Materials Science, Multidisciplinary)Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.
Science, 364(6437), p.272 - 275, 2019/04
Times Cited Count：233 Percentile：99.74(Multidisciplinary Sciences)The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.
Nakano, Masanao; Fujita, Hiroki; Mizutani, Tomoko; Nagaoka, Mika; Inoue, Kazumi; Koike, Yuko; Yamada, Ryohei; Yoshii, Hideki*; Hiyama, Yoshinori*; Otani, Kazunori*; et al.
JAEA-Review 2018-028, 120 Pages, 2019/02
JAEA-Review-2018-028.pdf:2.69MB
Based on the regulations (the safety regulation of Tokai Reprocessing Plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and by law of Ibaraki Prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2017. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.
Nakano, Masanao; Fujita, Hiroki; Nagaoka, Mika; Inoue, Kazumi; Koike, Yuko; Yoshii, Hideki*; Hiyama, Yoshinori*; Otani, Kazunori*; Kikuchi, Masaaki*; Sakauchi, Nobuyuki*; et al.
JAEA-Review 2017-037, 119 Pages, 2018/03
JAEA-Review-2017-037.pdf:2.58MB
Based on the regulations (the safety regulation of Tokai Reprocessing Plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki Prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2016. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.
Ge in the normal stateNakatani, Yasuhiro*; Aratani, Hidekazu*; Fujiwara, Hidenori*; Mori, Takeo*; Tsuruta, Atsushi*; Tachibana, Shoichi*; Yamaguchi, Takashi*; Kiss, Takayuki*; Yamasaki, Atsushi*; Yasui, Akira*; et al.
Physical Review B, 97(11), p.115160_1 - 115160_7, 2018/03
Times Cited Count：3 Percentile：16.62(Materials Science, Multidisciplinary)Yamaguchi, Yasuhiro*; Giachino, A.*; Hosaka, Atsushi; Santopinto, E.*; Takeuchi, Sachiko*; Takizawa, Makoto*
Physical Review D, 96(11), p.114031_1 - 114031_25, 2017/12
Times Cited Count：47 Percentile：90.91(Astronomy & Astrophysics)GeNakatani, Yasuhiro*; Fujiwara, Hidenori*; Aratani, Hidekazu*; Mori, Takeo*; Tachibana, Shoichi*; Yamaguchi, Takashi*; Kiss, Takayuki*; Yamasaki, Atsushi*; Yasui, Akira*; Yamagami, Hiroshi*; et al.
Journal of Electron Spectroscopy and Related Phenomena, 220, p.50 - 53, 2017/01
Times Cited Count：1 Percentile：9.51(Spectroscopy)We report the soft X-ray angle-resolved photoemission study for LaNiGe to reveal the electronic structures derived from non-4
bands of the heavy fermion compound CeNiGe. The photoemission spectra recorded at the La M
absorption edges clearly show the enhancement of the La 5
components in the valence band spectra. The circular dichroism of photoemission spectra reveals the band-dependent dichroic response due to the orbital symmetry.
; Soft X-ray absorption, magnetic circular dichroism, and angle-resolved photoemission spectroscopiesSaito, Yuji; Fujiwara, Hidenori*; Yamaguchi, Takashi*; Nakatani, Yasuhiro*; Mori, Takeo*; Fuchimoto, Hiroto*; Kiss, Takayuki*; Yasui, Akira*; Miyawaki, Jun*; Imada, Shin*; et al.
Journal of the Physical Society of Japan, 85(11), p.114713_1 - 114713_7, 2016/11
Times Cited Count：13 Percentile：65.62(Physics, Multidisciplinary)We report on the electronic structures of ferromagnetic CeAgSb using soft X-ray absorption (XAS), magnetic circular dichroism (XMCD), and angle-resolved photoemission (ARPES) spectroscopies. The Ce 
XAS spectra show very small satellite structures, reflecting a strongly localized character of the Ce 4
electrons. The linear dichroism effects in the Ce XAS spectra demonstrate the ground-state Ce 4 symmetry of 
, the spatial distribution of which is directed along the 
-axis. Nevertheless, ARPES spectra at the Ce 3-4 resonance show the momentum dependence of the intensity ratio between Ce 4
and 4
peaks in a part of the Brillouin zone, suggesting the non negligible momentum-dependent hybridization effect between the Ce 4 and the conduction electrons. This is associated with the moderate mass enhancement in CeAgSb.
Br-
-methyl-phenylalanine for tumor PET imagingHanaoka, Hirofumi*; Ohshima, Yasuhiro; Suzuki, Yurika*; Yamaguchi, Aiko*; Watanabe, Shigeki; Uehara, Tomoya*; Nagamori, Shushi*; Kanai, Yoshikatsu*; Ishioka, Noriko; Tsushima, Yoshito*; et al.
Journal of Nuclear Medicine, 56(5), p.791 - 797, 2015/05
Times Cited Count：17 Percentile：62.05(Radiology, Nuclear Medicine & Medical Imaging)Kaira, Kyoichi*; Sunose, Yutaka*; Ohshima, Yasuhiro; Ishioka, Noriko; Arakawa, Kazuhisa*; Ogawa, Tetsushi*; Sunaga, Noriaki*; Shimizu, Kimihiro*; Tominaga, Hideyuki*; Oriuchi, Noboru*; et al.
BMC Cancer, 13, p.482_1 - 482_12, 2013/10
Times Cited Count：68 Percentile：88.11(Oncology)