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Journal Articles

Fine structure in the $$alpha$$ decay of $$^{223}$$U

Sun, M. D.*; Liu, Z.*; Huang, T. H.*; Zhang, W. Q.*; Andreyev, A. N.; Ding, B.*; Wang, J. G.*; Liu, X. Y.*; Lu, H. Y.*; Hou, D. S.*; et al.

Physics Letters B, 800, p.135096_1 - 135096_5, 2020/01

 Times Cited Count:1 Percentile:22.94(Astronomy & Astrophysics)

Journal Articles

Adsorption of Cs onto biogenic birnessite; Effects of layer structure, ionic strength, and competition cations

Yu, Q.*; Tanaka, Kazuya; Kozai, Naofumi; Sakamoto, Fuminori; Tani, Yukinori*; Onuki, Toshihiko

ACS Earth and Space Chemistry (Internet), 2(8), p.797 - 810, 2018/08

Most of Mn oxides are biogenic and known to adsorb cesium (Cs) on the surface. This study investigated structural transformation of biogenic birnessite by accommodating commonly occurring natural heavy metals (Zn, Ni) during the formation of Mn oxides and the influence of those metals on the adsorption behavior of Cs on Mn oxides. It was found that the presence of heavy metals during bio-oxidation of Mn(II), followed by exposure to a low pH aqueous solution, increased the number of available layer vacancies, which consequently increased the adsorption capacity of Cs in the final product birnessite.

Journal Articles

Liquid-like thermal conduction in intercalated layered crystalline solids

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:39 Percentile:3.48(Chemistry, Physical)

Journal Articles

Quantitative analysis of radiocesium retention onto birnessite and todorokite

Yu, Q.*; Onuki, Toshihiko*; Kozai, Naofumi; Sakamoto, Fuminori; Tanaka, Kazuya; Sasaki, Keiko*

Chemical Geology, 470, p.141 - 151, 2017/10

 Times Cited Count:3 Percentile:68.72(Geochemistry & Geophysics)

In this work, the Cs retention onto two types of Mn oxide was investigated. We found that Todorokite has sorption sites with a higher selectivity for Cs than birnessite. When the initial Cs concentration was 10$$^{-9}$$ mol/L for the sorption experiments, approximately 34% of the sorbed Cs was residual in the todorokite after the extraction using 1 M NaCl and NH$$_{4}$$Cl; this value was much higher than the results for the Cs-sorbed birnessite. These results strongly suggest that todorokite contributes to the fixation of radioactive Cs in soils.

Journal Articles

Fungus-promoted transformation of lanthanides during the biooxidation of divalent manganese

Yu, Q.; Onuki, Toshihiko; Tanaka, Kazuya; Kozai, Naofumi; Yamasaki, Shinya*; Sakamoto, Fuminori; Tani, Yukinori*

Geochimica et Cosmochimica Acta, 174, p.1 - 12, 2016/02

 Times Cited Count:13 Percentile:28.39(Geochemistry & Geophysics)

Although microorganisms possess high sorption capability for lanthanides (Lns), their biological response affecting Lns migration is unclear. We investigated the effects of microbial activity on transformation of Lns by contact of Lns with Aeremonium strictum under metabolically active condition with Mn(II). A biomolecule that specifically complex to Ce(IV) was found to be released from the fungal cell, facilitating the desorption of Ce(IV) from Mn oxide. This biomolecule was not associated with any other trivalent Lns or Fe, which differed from those non-nuclide-specific organic substances released from resting cells, as reported previously.

Journal Articles

Sorption of trivalent cerium by a mixture of microbial cells and manganese oxides; Effect of microbial cells on the oxidation of trivalent cerium

Onuki, Toshihiko; Jiang, M.*; Sakamoto, Fuminori; Kozai, Naofumi; Yamasaki, Shinya*; Yu, Q.; Tanaka, Kazuya; Utsunomiya, Satoshi*; Xia, X.*; Yange, K.*; et al.

Geochimica et Cosmochimica Acta, 163, p.1 - 13, 2015/08

 Times Cited Count:10 Percentile:55.59(Geochemistry & Geophysics)

The association of Ce(III) with the microbial cell surface and the formation of Ce phosphate nano-particles are responsible for suppressing the oxidation of Ce(III) to Ce(IV) in the mixtures.

Journal Articles

Origin of dramatic oxygen solute strengthening effect in titanium

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:106 Percentile:2.85(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 $$alpha$$-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.

Journal Articles

In situ X-ray diffraction investigation of the evolution of a nanocrystalline lithium-ion sieve from biogenic manganese oxide

Yu, Q.; Sasaki, Keiko*

Hydrometallurgy, 150, p.253 - 258, 2014/12

 Times Cited Count:4 Percentile:68(Metallurgy & Metallurgical Engineering)

Journal Articles

Adsorption characteristics of Cs$$^{+}$$ on biogenic birnessite

Sasaki, Keiko*; Yu, Q.; Momoki, Taichi*; Kaseyama, Takuya*

Applied Clay Science, 101, p.23 - 29, 2014/11

 Times Cited Count:7 Percentile:65.48(Chemistry, Physical)

Journal Articles

Cobalt(II) oxidation by biogenic Mn oxide produced by $$Pseudomonas$$ sp. strain NGY-1

Tanaka, Kazuya*; Yu, Q.; Sasaki, Keiko*; Onuki, Toshihiko

Geomicrobiology Journal, 30(10), p.874 - 885, 2013/08

 Times Cited Count:6 Percentile:73.4(Environmental Sciences)

no abstracts in English

Journal Articles

Diluted ferromagnetic semiconductor Li(Zn,Mn)P with decoupled charge and spin doping

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:58 Percentile:6.84(Materials Science, Multidisciplinary)

Journal Articles

Zinc sorption during bio-oxidation and precipitation of manganese modifies the layer stacking of biogenic birnessite

Yu, Q.; Sasaki, Keiko*; Tanaka, Kazuya*; Onuki, Toshihiko; Hirajima, Tsuyoshi*

Geomicrobiology Journal, 30(9), p.829 - 839, 2013/07

 Times Cited Count:21 Percentile:32.76(Environmental Sciences)

no abstracts in English

Journal Articles

Structural factors of biogenic birnessite produced by fungus ${it Paraconiothyrium}$ sp. WL-2 strain affecting sorption of Co$$^{2+}$$

Yu, Q.*; Sasaki, Keiko*; Tanaka, Kazuya*; Onuki, Toshihiko; Hirajima, Tsuyoshi*

Chemical Geology, 310-311, p.106 - 113, 2012/06

 Times Cited Count:40 Percentile:16.91(Geochemistry & Geophysics)

These results strongly suggested that the interlayer Mn(III) can oxidize the adsorbed Co$$^{2+}$$ to Co$$^{3+}$$, resulting in specific adsorption of Co$$^{2+}$$ by biogenic birnessite.

Journal Articles

Li(Zn,Mn)As as a new generation ferromagnet based on a I-II-V semiconductor

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:118 Percentile:6.04(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$$_{1+y}$$(Zn$$_{1-x}$$Mn$$_x$$)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.

Journal Articles

Guiding and confining fast electrons by transient electric and magnetic fields with a plasma inverse cone

Lei, A. L.*; Cao, L. H.*; Yang, X. Q.*; Tanaka, Kazuo*; Kodama, Ryosuke*; He, X. T.*; Mima, Kunioki*; Nakamura, Tatsufumi; Norimatsu, Takayoshi*; Yu, W.*; et al.

Physics of Plasmas, 16(2), p.020702_1 - 020702_4, 2009/02

 Times Cited Count:11 Percentile:54.15(Physics, Fluids & Plasmas)

The fast electron propagation in an inverse cone target is investigated computationally and experimentally. Two-dimensional particle-in-cell simulation shows that fast electrons with substantial numbers are generated at the outer tip of an inverse cone target irradiated by a short intense laser pulse. These electrons are guided and confined to propagate along the inverse cone wall, forming a large surface current. The experiment qualitatively verifies the guiding and confinement of the strong electron current in the wall surface. The large surface current and induced strong field s are of importance for fast ignition related research.

Journal Articles

The H-Invitational Database (H-InvDB); A Comprehensive annotation resource for human genes and transcripts

Yamasaki, Chisato*; Murakami, Katsuhiko*; Fujii, Yasuyuki*; Sato, Yoshiharu*; Harada, Erimi*; Takeda, Junichi*; Taniya, Takayuki*; Sakate, Ryuichi*; Kikugawa, Shingo*; Shimada, Makoto*; et al.

Nucleic Acids Research, 36(Database), p.D793 - D799, 2008/01

 Times Cited Count:50 Percentile:23.82(Biochemistry & Molecular Biology)

Here we report the new features and improvements in our latest release of the H-Invitational Database, a comprehensive annotation resource for human genes and transcripts. H-InvDB, originally developed as an integrated database of the human transcriptome based on extensive annotation of large sets of fulllength cDNA (FLcDNA) clones, now provides annotation for 120 558 human mRNAs extracted from the International Nucleotide Sequence Databases (INSD), in addition to 54 978 human FLcDNAs, in the latest release H-InvDB. We mapped those human transcripts onto the human genome sequences (NCBI build 36.1) and determined 34 699 human gene clusters, which could define 34 057 protein-coding and 642 non-protein-coding loci; 858 transcribed loci overlapped with predicted pseudogenes.

Journal Articles

Positron annihilation study of vacancy-type defects in silicon carbide co-implanted with aluminum and carbon ions

Oshima, Takeshi; Uedono, Akira*; Abe, Hiroshi; Chen, Z. Q.*; Ito, Hisayoshi; Yoshikawa, Masahito; Abe, Koji*; Eryu, Osamu*; Nakashima, Kenshiro*

Physica B; Condensed Matter, 308-310, p.652 - 655, 2001/12

 Times Cited Count:6 Percentile:60.86

Co-implantation of Al(2E18/cm3) and C(1E18/cm3) into 6H-SiC and subsequent thermal annealing up to 1650 C werer carried out. Vacancy-type defects in the implanted layer were studied by monoenergetic positron beams. The mean size of vacancy-type defects in as-implanted samples is found to be close to the size of divacancy. Although vacancy clsters near a surface region were created by 1000 C-annealing, clustering is suppressed in a deep region.The mean size of vacancys decrease by annealing above 1000 C, and major vacancy defects annealed out after annealing at 1400 C. No significant difference in defect annealing between only Al- and co-implanted samles was observed.This result suggests that electrical activation of Al is enhanced by the site competition mechanism.

Oral presentation

Development of negative Ce anomalies in biogenic Mn oxide; The Role of microorganism on REE mobility during the bio-oxidation of Mn$$^{2+}$$

Yu, Q.; Onuki, Toshihiko; Tanaka, Kazuya*; Kozai, Naofumi; Yamasaki, Shinya; Sakamoto, Fuminori; Tani, Yukinori*

no journal, , 

Oral presentation

Accumulation and chemical states of radiocesium by fungus Saccharomyces cerevisiae

Onuki, Toshihiko; Sakamoto, Fuminori; Kozai, Naofumi; Yamasaki, Shinya*; Yu, Q.

no journal, , 

In the present study, accumulation and chemical states change of Cs by unicellular fungus of Saccharomyces cerevisiae have been studied to elucidate the role of microorganisms in the migration of radiocesium in the environment. The accumulation experiments of radiocesium was carried out by using the agar medium containing $$^{137}$$Cs and a minerals. The order of accumulation of $$^{137}$$Cs in the cells was nearly the same as the inverse of distribution coefficient of mineral for $$^{137}$$Cs in the medium solution. These results indicate that the fungus accumulates radiocesium by competitively with minerals in the soils.

Oral presentation

Accumulation of radiocesium in filamentous fungi

Onuki, Toshihiko; Sakamoto, Fuminori; Kozai, Naofumi; Yamasaki, Shinya*; Yu, Q.

no journal, , 

Accumulation of Cs by filamentous fungi have been studied to elucidate the role of filamentous fungi collected in forest in the migration of radiocesium in the environment. Without mineral in the medium, the hyphae of the filamentous fungi accumulated radiocesium. When mineral was added in the medium, concentration of $$^{137}$$Cs in the hyphae decreased and was correlated with the inverse of Kd of minerals.

35 (Records 1-20 displayed on this page)