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Biosurface properties and lead adsorption in a clone of ${it Sphagnum palustre}$ (Mosses); Towards a unified protocol of biomonitoring of airborne heavy metal pollution

Di Palma, A.; Gonz$'a$lez, A. G.*; Adamo, P.*; Giordano, S.*; Reski, R.*; Pokrovsky, O. S.*

Chemosphere, 236, p.124375_1 - 124375_9, 2019/12

In this work we used field- and laboratory-grown S. palustre moss treated by EDTA and devitalized by oven drying, to elaborate a consistent procedure of metal and proton adsorption on moss surfaces and a biomonitoring protocol using cloned moss. Devitalization and EDTA treatments did not produce any measurable difference in terms of H$$^{+}$$ and Pb$$^{2+}$$ adsorption capacities of moss surfaces. Therefore, in view of the use of S. palustre clone for biomonitoring purposes, we recommend devitalization as unique treatment to perform with the aim to preserve the biomaterial before and after its exposure in bags.


Evidence for singular-phonon-induced nematic superconductivity in a topological superconductor candidate Sr$$_{0.1}$$Bi$$_{2}$$Se$$_{3}$$

Wang, J.*; Ran, K.*; Li, S.*; Ma, Z.*; Bao, S.*; Cai, Z.*; Zhang, Y.*; 中島 健次; 河村 聖子; $v{C}$erm$'a$k, P.*; et al.

Nature Communications (Internet), 10, p.2802_1 - 2802_6, 2019/06

Superconductivity mediated by phonons is typically conventional, exhibiting a momentum-independent $$s$$-wave pairing function, due to the isotropic interactions between electrons and phonons along different crystalline directions. Here, by performing inelastic neutron scattering measurements on a superconducting single crystal of Sr$$_{0.1}$$Bi$$_{2}$$Se$$_{3}$$, a prime candidate for realizing topological superconductivity by doping the topo-logical insulator Bi$$_{2}$$Se$$_{3}$$, we found that there exist singular phonons, with the linewidths of the acoustic phonons increasing substantially at long wavelengths, but only for those along the [001] direction. This observation indicates a large and singular electron-phonon coupling at small momenta, which we propose to give rise to the exotic $$p$$-wave nematic superconducting pairing in the MxBi$$_{2}$$Se$$_{3}$$ (M = Cu, Sr, Nb) superconductor family. Therefore, we show that these superconductors may be the first examples where electron-phonon interaction can induce more exotic superconducting pairing than the $$s$$-wave.


Emergence of a complete heavy-quark spin symmetry multiplet; Seven molecular pentaquarks in light of the latest LHCb analysis

Liu, M.-Z.*; Pan, Y.-W.*; Peng, F.-Z.*; S$'a$nchez-S$'a$nchez, M.*; Geng, L.-S.*; 保坂 淳; Valderrama, M. P.*

Physical Review Letters, 122(24), p.242001_1 - 242001_5, 2019/06

A recent analysis by the LHCb Collaboration suggests the existence of three narrow pentaquarklike states-the $$P_c$$(4312), $$P_c$$(4440), and $$P_c$$(4457)-instead of just one in the previous analysis [the $$P_c$$(4450)]. The closeness of the $$P_c$$(4312) to the $$bar{D}^{*}Sigma_c$$ threshold and the $$P_c$$(4440) and $$P_c$$(4457) to the $$bar{D}^{*}Sigma_c$$ threshold suggests a molecular interpretation of these resonances. We show that these three pentaquarklike resonances can be naturally accommodated in a contact-range effective field theory description that incorporates heavy-quark spin symmetry. This description leads to the prediction of all the seven possible $$S$$-wave heavy antimeson-baryon molecules [that is, there should be four additional molecular pentaquarks in addition to the $$P_c$$(4312), $$P_c$$(4440), and $$P_c$$(4457)], providing the first example of a heavy-quark spin symmetry molecular multiplet that is complete. If this is confirmed, it will not only give us an impressive example of the application of heavy-quark symmetries and effective field theories in hadron physics, it will also uncover a clear and powerful ordering principle for the molecular spectrum, reminiscent of the SU(3)-flavor multiplets to which the light hadron spectrum conforms.


Flow-electrode CDI removes the uncharged Ca-UO$$_{2}$$-CO$$_{3}$$ ternary complex from brackish potable groundwater; Complex dissociation, transport, and sorption

Ma, J.*; Zhang, Y.*; Collins, R. N.*; Tsarev, S.*; 青柳 登; Kinsela, A. S.*; Jones, A. M.*; Waite, T. D.*

Environmental Science & Technology, 53(5), p.2739 - 2747, 2019/03

 パーセンタイル:100(Engineering, Environmental)

Unacceptably high uranium concentrations in decentralized and remote potable groundwater resources, especially those of high hardness, are a common worldwide problem. The complexation of alkali earth metals, carbonate and uranium(VI) results in the formation of thermodynamically stable ternary aqueous species that are predominantly neutrally-charged. The removal of the uncharged (non-adsorbing) complexes is a problematic issue for many water treatment technologies. As such, we have evaluated the efficacy of a recently-developed electrochemical technology, termed flow-electrode capacitive deionization (FCDI), to treat a synthetic groundwater, the composition of which is comparable to groundwater resources in the Northern Territory, Australia. Theoretical calculations and time-resolved laser fluorescence spectroscopy analyses confirmed that the complex was the primary aqueous species followed. Results under different operating conditions demonstrated that FCDI is versatile in reducing uranium concentrations to $$<$$ 10 $$mu$$g L$$^{-1}$$ with low electrical consumption (e.g. $$sim$$ 0.1 kWh m$$^{-3}$$). It is concluded that the capability of FCDI to remove uranium under these common conditions depends on the dissociation kinetics of the complex in the electrical field.


Nuclear structure of $$^{76}$$Ni from the ($$p$$,$$2p$$) reaction

Elekes, Z.*; Kripk$'o$, $'A$*; Sohler, D.*; Sieja, K.*; 緒方 一介*; 吉田 数貴; Doornenbal, P.*; Obertelli, A.*; Authelet, G.*; 馬場 秀忠*; et al.

Physical Review C, 99(1), p.014312_1 - 014312_7, 2019/01

 パーセンタイル:100(Physics, Nuclear)

($$p$$,$$2p$$)反応による$$^{76}$$Niの核構造の探索実験を行った。Lenzi, Nowacki, Poves, Sieja相互作用を用いた殻模型計算では実験結果を説明しうる陽子空孔状態が得られており、理論的な断面積計算は実験値とよい一致を与えた。実験で得られたすべての状態を理論的に一意に決定することはできなかったが、過去の実験結果と同様にNi同位体でのZ = 28の大きなshell gapを示す結果が得られた。


Template-free fabrication of mesoporous alumina nanospheres using post-synthesis water-ethanol treatment of monodispersed aluminium glycerate nanospheres for molybdenum adsorption

Saptiama, I.*; Kaneti, Y. V.*; 鈴木 善貴; 土谷 邦彦; 福光 延吉*; 榮 武二*; Kim, J.*; Kang, Y.-M.*; 有賀 克彦*; 山内 悠輔*

Small, 14(21), p.1800474_1 - 1800474_14, 2018/05



Comparison of heavy-ion transport simulations; Collision integral in a box

Zhang, Y.-X.*; Wang, Y,-J.*; Colonna, M.*; Danielewicz, P.*; 小野 章*; Tsang, M. B.*; Wolter, H.*; Xu, J.*; Chen, L.-W.*; Cozma, D.*; et al.

Physical Review C, 97(3), p.034625_1 - 034625_20, 2018/03

 被引用回数:16 パーセンタイル:1.01(Physics, Nuclear)

2017年4月に開催された国際会議Transport2017において、重イオン核反応モデルの国際的な比較が議論された。重イオン加速器の安全評価や宇宙飛行士の被ばく評価等で重要な役割を果たすため、世界中で重イオン核反応の様々な理論モデルが開発されている。本研究はモデル間の共通点と差異を明らかにし、各モデルの問題点を明らかにした。比較において、辺の長さが20fmの直方体に320個の中性子と320個の陽子をランダム配置し、それらが時間発展に伴って起こす散乱の回数や散乱時のエネルギーなどを計算する条件が設定された。また、結果以外にも、理論モデルを構成するアルゴリズムについても比較を行った。発表者は重イオン核反応モデルJQMD(JAERI Quantum Molecular Dynamics)を用いて計算を行い、世界で開発されている15の計算コードによる計算結果と比較した。コードアルゴリズムの比較では、JQMDは必ず陽子から 優先的に衝突確率を計算し、その後に中性子の衝突を計算するため、物理描像の妥当性が指摘された。一方、JQMDは他のモデルとほぼ同じ計算結果を出すことも判明した。衝突回数や運動量の計算値が平均から2倍以上乖離するモデルもある中で、JQMDは本計算条件で安定した性能を発揮することが確認された。


Molybdenum adsorption properties of alumina-embedded mesoporous silica for medical radioisotope production

Saptiama, I.*; Kaneti, Y. V.*; Oveisi, H.*; 鈴木 善貴; 土谷 邦彦; 高井 公子*; 榮 武二*; Pradhan, S.*; Hossain, M. S. A.*; 福光 延吉*; et al.

Bulletin of the Chemical Society of Japan, 91(2), p.195 - 200, 2018/02

 被引用回数:13 パーセンタイル:4.41(Chemistry, Multidisciplinary)



Mesoporous alumina as an effective adsorbent for molybdenum (Mo) toward Instant production of radioisotope for medical use

Saptiama, I.*; Kaneti, Y. V.*; 鈴木 祐未*; 鈴木 善貴; 土谷 邦彦; 榮 武二*; 高井 公子*; 福光 延吉*; Alothman, Z. A.*; Hossain, M. S. A.*; et al.

Bulletin of the Chemical Society of Japan, 90(10), p.1174 - 1179, 2017/10

 被引用回数:23 パーセンタイル:7.51(Chemistry, Multidisciplinary)



Shell evolution beyond $$Z$$=28 and $$N$$=50; Spectroscopy of $$^{81,82,83,84}$$Zn

Shand, C. M.*; Podoly$'a$k, Zs.*; G$'o$rska, M.*; Doornenbal, P.*; Obertelli, A.*; Nowacki, F.*; Otsuka, T.*; Sieja, K.*; Tostevin, J. A.*; Tsunoda, T.*; et al.

Physics Letters B, 773, p.492 - 497, 2017/10

 被引用回数:8 パーセンタイル:14.67(Astronomy & Astrophysics)

Low-lying states in neutron-rich $$^{81,82.83.84}$$Zn nuclei were measured for the first time via in-beam $$gamma$$-ray spectroscopy at RIKEN. These include the 4$$_1^+$$ to 2$$_1^+$$ in $$^{82}$$Zn and the 2$$_1^+$$ to 0$$_1^+$$ and 4$$_1^+$$ to 2$$_1^+$$ in $$^{84}$$Zn. The reduced E($$2^+$$) energies and increased E(4$$^+$$)/E(2$$^+$$) ratios at $$N$$=52,54 compared to $$^{80}$$Zn attest that the magicity is confined just on the neutron number $$N$$=50 only. The levels observed in $$^{84}$$Zn suggest the onset of deformation towards heavier Zn isotopes. The data were compared to state-of-the-art shell model calculations.


Magnetic structure and dispersion relation of the $$S$$=1/2 quasi-one-dimensional Ising-like antiferromagnet BaCo$$_{2}$$V$$_{2}$$O$$_{8}$$ in a transverse magnetic field

松田 雅昌*; 大西 弘明; 奥谷 顕*; Ma, J.*; Agrawal, H.*; Hong, T.*; Pajerowski, D. M.*; Copley, J. R. D.*; 奥西 巧一*; 森 道康; et al.

Physical Review B, 96(2), p.024439_1 - 024439_8, 2017/07

 被引用回数:2 パーセンタイル:66.33(Materials Science, Multidisciplinary)

BaCo$$_{2}$$V$$_{2}$$O$$_{8}$$ consists of Co chains, in which Co$$^{2+}$$ ion carries a fictitious spin $$frac{1}{2}$$ with Ising anisotropy. We performed elastic and inelastic neutron scattering experiments in BaCo$$_{2}$$V$$_{2}$$O$$_{8}$$ in magnetic field perpendicular to the $$c$$ axis which is the chain direction. With applying magnetic field along the $$a$$ axis at 3.5 K, the antiferromagnetic order with the easy axis along the $$c$$ axis, observed in zero magnetic field, is completely suppressed at 8 T, while the magnetic field gradually induces an antiferromagnetic order with the spin component along the $$b$$ axis. We also studied magnetic excitations as a function of transverse magnetic field. The lower boundary of the spinon excitations splits gradually with increasing magnetic field. The overall feature of the magnetic excitation spectra in magnetic field is reproduced by the theoretical calculation based on the spin $$frac{1}{2}$$ $$XXZ$$ antiferromagnetic chain model, which predicts that the dynamic magnetic structure factor of the spin component along the chain direction is enhanced and that along the field direction has clear incommensurate correlations.


Shape evolution in neutron-rich krypton isotopes beyond N=60; First spectroscopy of $$^{98,100}$$Kr

Flavigny, F.*; Doornenbal, P.*; Obertelli, A.*; Delaroche, J.-P.*; Girod, M.*; Libert, J.*; Rodriguez, T. R.*; Authelet, G.*; Baba, H.*; Calvet, D.*; et al.

Physical Review Letters, 118(24), p.242501_1 - 242501_6, 2017/06

 被引用回数:14 パーセンタイル:9.07(Physics, Multidisciplinary)

The first $$gamma$$-ray spectroscopy of very neutron rich $$^{98,100}$$Kr isotopes was carried out at the RIBF at RIKEN Nishina center. Excited states in these isotopes were populated via (p,2p) reactions using radioactive $$^{99,101}$$Rb beams accelerated to 220 MeV/nucleon. The new data show a significant increase in deformation beyond N=60, as well as competing configurations (shape-coexistence) at low energy. The data were compared with beyond-mean-field calculations which predict level energies in good agreement with observation, and suggest oblate-prolate shape coexistence.


$$gamma$$ decay of unbound neutron-hole states in $$^{133}$$Sn

Vaquero, V.*; Jungclaus, A.*; Doornenbal, P.*; Wimmer, K.*; Gargano, A.*; Tostevin, J. A.*; Chen, S.*; N$'a$cher, E.*; Sahin, E.*; 志賀 慶明*; et al.

Physical Review Letters, 118(20), p.202502_1 - 202502_5, 2017/05

 被引用回数:8 パーセンタイル:18.97(Physics, Multidisciplinary)

Excited states in $$^{133}$$Sn were populated following one-neutron knockout reaction from an unstable $$^{134}$$Sn beam at the RIBF laboratory in RIKEN. In addition to the already known $$gamma$$ rays, additional $$gamma$$ strength was observed for the first time in the excitation-energy range 3.5-5.5 MeV. Since the neutron separation energy of $$^{133}$$Sn is low, this observation provides direct evidence for the radioactive decay of neutron-unbound states in this nucleus. The ability of $$gamma$$ decay to compete with neutron emission was attributed to a mismatch between the wave functions of the initial and final states in the neutron emission case. These findings suggest that in the region south-east of $$^{132}$$Sn, nuclear structure effects play a significant role in the decay of unbound states, which are instead usually ignored in the evaluation of neutron-emission probabilities in astrophysical simulations.


Low-lying structure and shape evolution in neutron-rich Se isotopes

Chen, S.*; Doornenbal, P.*; Obertelli, A.*; Rodriguez, T. R.*; Authelet, G.*; Baba, H.*; Calvet, D.*; Ch$^a$teau, F.*; Corsi, A.*; Delbart, A.*; et al.

Physical Review C, 95(4), p.041302_1 - 041302_6, 2017/04

 被引用回数:11 パーセンタイル:8.11(Physics, Nuclear)

Neutron-rich isotopes of selenium, $$^{88,90,92,94}$$Se, where studied via in beam $$gamma$$-ray spectroscopy after nucleon removal reactions at RIBF in RIKEN. The low-energy excitations of these nuclei were investigated using $$gamma$$-$$gamma$$ coincidences, and the first and second excited 2$$^+$$ states were found at remarkably low energies. The analysis and comparison with self-consistent beyond-mean field calculations suggest that both shape coexistence and triaxiality are needed to describe these isotopes.


Type II shell evolution in $$A=70$$ isobars from the $$N geq 40$$ island of inversion

Morales, A. I.*; Benzoni, G.*; Watanabe, H.*; 角田 佑介*; Otsuka, T.*; 西村 俊二*; Browne, F.*; Daido, R.*; Doornenbal, P.*; Fang, Y.*; et al.

Physics Letters B, 765, p.328 - 333, 2017/02

 被引用回数:10 パーセンタイル:8.11(Astronomy & Astrophysics)

The level schemes of neutron-rich isotopes $$^{70}$$Co and $$^{70}$$Ni were populated in the $$beta$$ decay of $$^{70}$$Fe and studied using $$beta$$-delayed $$gamma$$-ray spectroscopy of the $$beta$$ decay, at the RIBF in RIKEN, Japan. The experimental results were compared to state-of-the-art shell-model calculations, and indicate a dominance of prolate deformation in the low-lying states, coexisting with spherical states. The $$beta$$ decay of the $$A=70$$ isobars is shown to progress in accordance to a new type of shell evolution, the so-called Type II, which involves many particle-hole excitations across energy gaps.


Are there signatures of harmonic oscillator shells far from stability?; First spectroscopy of $$^{110}$$Zr

Paul, N.*; Corsi, A.*; Obertelli, A.*; Doornenbal, P.*; Authelet, G.*; Baba, H.*; Bally, B.*; Bender, M.*; Calvet, D.*; Ch$^a$teau, F.*; et al.

Physical Review Letters, 118(3), p.032501_1 - 032501_7, 2017/01

 被引用回数:14 パーセンタイル:9.07(Physics, Multidisciplinary)

The first measurement of $$gamma$$ rays emitted by the very neutron rich nuclei $$^{112}$$Mo (Z=42) and $$^{110}$$Zr (Z=40) was carried out at the RIBF facility at RIKEN. These data shine light on the postulated N=70 harmonic oscillator shell. If the spin-orbit splitting which gives rise to the N=82 shell gap is reduced in very neutron-rich nuclei, the harmonic oscillator gap at N=70 should open instead. However, both the measured energy of the first excited state $$^{112}$$Mo and $$^{110}$$Zr, respectively 235(7) keV and 185(11) keV, and their E(4$$^+$$)/E(2$$^+$$) ratio, indicate that these nuclei are good rotors, and exclude the shell stabilization scenario at Z=40 and N=70. These results were compared to state-of-the-art density functional theoretical calculations using Gogny and Skyrme effective interactions.


Low-lying excitations in $$^{72}$$Ni

Morales, A. I.*; Benzoni, G.*; Watanabe, H.*; 西村 俊二*; Browne, F.*; Daido, R.*; Doornenbal, P.*; Fang, Y.*; Lorusso, G.*; Patel, Z.*; et al.

Physical Review C, 93(3), p.034328_1 - 034328_14, 2016/03

 被引用回数:11 パーセンタイル:14.96(Physics, Nuclear)

Low-lying excited states in $$^{72}$$Ni have been investigated at RIKEN by studying the $$beta$$ decay of $$^{72}$$Co to $$^{72}$$Ni. $$^{72}$$Co was separated with BigRIPS, implanted into the WaS3ABi Silicon array, and the $$gamma$$ ray measured using the EURICA $$gamma$$ spectrometer. From the analysis, 60 new $$gamma$$-ray transitions and 21 new levels in $$^{72}$$Ni were observed. The new experimental information is compared to shell-model calculations which include neutron excitation across the $$fpg$$ shell. The calculations reproduce rather well the observed states, implying that a clear understanding of these low-lying excitations has been achieved.


Decay properties of $$^{68,69,70}$$Mn; Probing collectivity up to N=44 in Fe isotopic chain

Benzoni, G.*; Morales, A. I.*; Watanabe, H.*; 西村 俊二*; Coraggio, L.*; Itaco, N.*; Gargano, A.*; Browne, F.*; Daido, R.*; Doornenbal, P.*; et al.

Physics Letters B, 751, p.107 - 112, 2015/12

 被引用回数:14 パーセンタイル:15.32(Astronomy & Astrophysics)

The $$beta$$ decays of $$^{68,69,70}$$Mn have been measured at the RIBF facility at RIKEN using the EURICA $$gamma$$ spectrometer combined with an active stopper consisting of a stack of Si detectors. Half-lives and $$beta$$-delayed neutron emission probabilities have been extracted for these decays, together with first experimental information on excited states populated in $$^{69,70}$$Fe. The data indicate a continuously increasing deformation for Fe isotopes up to A=70, and interpreted to be due to the interplay between quadrupole correlation of specific neutron orbitals and the monopole component of the proton-neutron interaction.


Melting of Pb charge glass and simultaneous Pb-Cr charge transfer in PbCrO$$_{3}$$ as the origin of volume collapse

Yu, R.*; 北條 元*; 綿貫 徹; 水牧 仁一朗*; 溝川 貴司*; 岡 研吾*; Kim, H.*; 町田 晃彦; 榊 浩司*; 中村 優美子*; et al.

Journal of the American Chemical Society, 137(39), p.12719 - 12728, 2015/10

 被引用回数:13 パーセンタイル:37.88(Chemistry, Multidisciplinary)



Inter-code comparison of TRIPOLI${textregistered}$ and MVP on the MCNP criticality validation suite

Brun, E.*; Zoia, A.*; Trama, J. C.*; Lahaye, S.*; 長家 康展

Proceedings of International Conference on Nuclear Criticality Safety (ICNC 2015) (DVD-ROM), p.351 - 360, 2015/09

本論文は、CEA Saclayと原子力機構で行われている、選抜ICSBEPベンチマーク問題に対するモンテカルロコードTRIPOLI${textregistered}$とMVPのコード間比較についての共同研究の結果を発表するものである。本研究の目標は、臨界安全における厳密なコード間比較を行うため、共通のモンテカルロ入力データを用意することである。参照入力データとして、他のモンテカルロコード開発者が将来簡単にコード間比較できるよう、MCNP臨界計算妥当性評価ベンチマーク集を用いることとした。コード間比較の目的のため、MCNPの入力データを近似なく翻訳し、TRIPOLI${textregistered}$とMVPの入力データを作成した。両コードともENDF/B-VII.0を用い、オリジナルMCNP入力データとできる限り同じ条件で計算を行った。この要旨では、BIGTENベンチマークの予備結果のみ示す。本論文では、31ベンチマーク問題すべての結果を示す予定である。将来、このデータベースは、核データ評価の感度解析、CPU時間と性能指数の比較にも役立つであろう。

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