Updated on 2024/11/07

写真a

 
KONISHI Hiromi
 
Organization
Academic Assembly Institute of Science and Technology CHIKYU SEIBUTSU KAGAKU KEIRETU Professor
Faculty of Science Professor
Graduate School of Science and Technology Environmental Science and Technology Earth Science Professor
Title
Professor
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Degree

  • 博士(学術) ( 1991.9   新潟大学 )

Research Areas

  • Natural Science / Solid earth sciences

Research History (researchmap)

  • Professor, Department of Geology, Niigata University

    2013.3

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  • Assistant Scientist of the Departments of Geoscience, University of Wisconsin-Madison. Lab Manager at The S.W. Bailey X-ray Diffraction Laboratory.

    2009.11 - 2013.2

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  • Research Associate of the Departments of Geology and Geophysics and Mechanical Engineering, University of Wisconsin-Madison, Lab Manager at The S.W. Bailey X-ray Diffraction Laboratory.

    2006.10 - 2009.10

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  • Postdoctoral Research Associate, Johns Hopkins University and Indiana University

    2004.9 - 2005.8

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  • Postdoctoral Research Associate, University of New Mexico

    2002.12 - 2004.8

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  • Postdoctoral Research Associate, Arizona State University

    1999.3 - 2002.3

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  • Research Assistant (助手), Departments of Physics and Applied Physics, Nihon University

    1995.4 - 1999.3

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  • Research Fellow (研究生) , Graduate School of Science and Technology, Niigata University

    1991.10 - 1995.3

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Research History

  • Niigata University   Graduate School of Science and Technology Environmental Science and Technology Earth Science   Professor

    2013.3

  • Niigata University   Faculty of Science Department of Geology   Professor

    2013.3 - 2017.3

Education

  • Niigata University   M.S.

    - 1988

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    Country: Japan

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  • Niigata University   B.S.

    - 1986

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    Country: Japan

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  • Niigata University   Ph.D.

    1991.9

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    Country: Japan

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Papers

  • Inhibitory Effects of Polysaccharides on the Dolomitization Reaction of Calcite at 200 °C

    Yang Wei, Hiromi Konishi

    Minerals   14 ( 7 )   721 - 721   2024.7

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    Publishing type:Research paper (scientific journal)   Publisher:MDPI AG  

    This study investigates the impact of dissolved carboxymethyl cellulose (CMC) and agar on the dolomitization reaction of calcite at 200 °C. Previous studies have suggested that CMC and agar promote dolomite precipitation at room temperature. However, this study found that their decomposition products hinder the reaction at 200 °C, with uncertainty about their role at other temperatures. The inhibitory effect of the decomposition products could be attributed to their adsorption onto calcite surfaces, which hinders their dissolution. This results in a longer reaction induction period and replacement period. Regression analysis demonstrates that the 0.1 g/L agar and 0.2 g/L CMC series decrease the cation ordering rate of dolomite produced from synthetic calcite when compared with series without polysaccharides. In contrast, the 0.1 g/L CMC series shows a slight increase in the cation ordering rate compared with series without polysaccharides. The findings of this study suggest a notable potential impact of the decomposition products of polysaccharides on the ordering of dolomite, although it is uncertain whether they inhibit this ordering process. The inhibitory effect observed in the decomposition products of CMC and agar could also exist in the decomposition products of the extracellular polymeric substances (EPS) and bacteria cell walls found in sedimentary rocks during burial diagenesis. Therefore, further research is necessary to understand the role of EPS and bacteria cell walls in dolomitization, since their impact is not always predictable.

    DOI: 10.3390/min14070721

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  • Investigation on Shock Metamorphism of Anatase by Supersonic Microprojectile Impact

    Seungyeol Lee, Jizhe Cai, Shiyun Jin, Hiromi Konishi, Dongzhou Zhang, Amanda S. Barnard, Ramathasan Thevamaran, Huifang Xu

    ACS Earth and Space Chemistry   7 ( 10 )   1905 - 1915   2023.10

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    Publishing type:Research paper (scientific journal)   Publisher:American Chemical Society (ACS)  

    DOI: 10.1021/acsearthspacechem.3c00057

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  • Precipitation of low-temperature disordered dolomite induced by extracellular polymeric substances of methanogenic Archaea<i>Methanosarcina barkeri</i>: Implications for sedimentary dolomite formation

    Fangfu Zhang, Huifang Xu, Evgenya S. Shelobolina, Hiromi Konishi, Eric E. Roden

    American Mineralogist   106 ( 1 )   69 - 81   2021.1

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    Publishing type:Research paper (scientific journal)   Publisher:Mineralogical Society of America  

    Abstract

    A correlation between methanogenesis and dolomite formation has been reported; however, the mechanism underlying this association is not fully understood. In this study, we conducted forced carbonate precipitation experiments at room temperature in calcite-seeded Ca/Mg carbonate solutions containing either purified non-living biomass or bound extracellular polymeric substances (EPS) of the methanogen Methanosarcina barkeri. Purified non-living biomass and bound EPS was used so as to avoid the possible influence of the complex components of the growing microbial culture on carbonate crystallization. Our results demonstrated that non-living biomass of M. Barkeri can enhance the Mg incorporation into calcitic structure and induce the crystallization of disordered dolomite. In the presence of ~113 mg L–1 of non-living biomass, disordered dolomite with ~41 and 45 mol% of MgCO3 was precipitated in solutions with initial Mg:Ca ratios of 5:1 and 8:1, respectively. A systematic increase in the MgCO3 contents of the precipitated Ca-Mg carbonates was also observed with the increased non-living biomass concentration. Bound EPS was shown to be the component of non-living biomass that catalyzed the precipitation of disordered dolomite. At only ~25 mg L–1 of bound EPS, disordered dolomite with ~47 and 48 mol% of MgCO3 was precipitated in solutions with initial Mg:Ca ratios of 5:1 and 8:1, respectively. We propose that adsorption of bound EPS to growing carbonate surfaces through hydrogen bonding is the key to catalyzing disordered dolomite crystallization, and that this mechanism is also applicable to natural EPS-induced dolomite formation. This study provides significant insight into the formation mechanism of microbial-induced dolomite with high δ13C values.

    DOI: 10.2138/am-2020-7381

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  • Occurrence of ss-cristobalite precipitates in omphacite of UHP eclogite and its petrological implication

    Xu, HF (Xu, Huifang, Konishi, H, onishi, Hiromi, Sun, XM (Sun, Xiaoming

    GEOCHIMICA ET COSMOCHIMICA ACTA   74   A1160 - A1160   2020.12

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  • Radiocesium distribution in the sediments of the Odaka River estuary, Fukushima, Japan

    Hiroki Hagiwara, Takahiro Nakanishi, Hiromi Konishi, Tadahiko Tsuruta, Toshiharu Misonou, Kenso Fujiwara, Akihiro Kitamura

    Journal of Environmental Radioactivity   220-221   106294 - 106294   2020.9

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.jenvrad.2020.106294

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  • Mineral composition characteristics of radiocesium sorbed and transported sediments within the Tomioka river basin in Fukushima Prefecture

    Hiroki Hagiwara, Hiromi Konishi, Takahiro Nakanishi, Kenso Fujiwara, Kazuki Iijima, Akihiro Kitamura

    Journal of Environmental Radioactivity   211   106042 - 106042   2020.1

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.jenvrad.2019.106042

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  • Precipitates of α-cristobalite and silicate glass in UHP clinopyroxene from a Bohemian Massif eclogite

    Tina R. Hill, Hiromi Konishi, Franklin Hobbs, Seungyeol Lee, Huifang Xu

    American Mineralogist   104 ( 10 )   1402 - 1415   2019.10

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    Publishing type:Research paper (scientific journal)   Publisher:Mineralogical Society of America  

    Abstract

    Low-pressure metastable nanoscale crystals of α-cristobalite have been observed epitaxially ex-solved in cores of UHP clinopyroxene from the Bohemian Massif, Czech Republic. SAED patterns and HRTEM images detail the close structural relationship between host clinopyroxene and α-cristobalite precipitate: [001]Di||[010]α, (010)Di ~||(101)α. TEM results indicate that α-cristobalite exsolved from host clinopyroxene. Non-crystalline Al-bearing silicate phases, also exsolved from UHP clinopyroxene, possesses Al/Si ratios close to eutectic compositions in the system NaAlSi3O8-SiO2-H2O system. The presence of glass exsolution suggests a high-temperature formation environment and presence of water. The α-cristobalite formed in a localized low-pressure, micro-environment formed through exsolution of vacancies and excess silica from the host pyroxene lattice. This micro-environment may be a result of negative density changes due to excess lower density silica exsolving from higher density pyroxene during an exsolution process that involved no localized volume change. Interface-controlled exsolution via lattice matching at the diopside/cristobalite interface, and stability changes and melting point depression due to nanoscale size effects contributed to the formation and persistence of this metastable phase. Amphibole in association with α-cristobalite and some non-crystalline silicate phases may be a clue to localized water quantities; silica exsolution with amphibole may have formed below the eutectic temperature and at a later stage than non-crystalline silicate phases without amphibole. Silica rods in Nové Dvory clinopyroxenes were previously thought to be quartz; however, our investigation reveals various low-pressure, high-temperature, and/or metastable phases greatly affected by the presence of vacancy and OH in clinopyroxenes. The results will help us better understand OH in the UHP pyroxene and even water release in the mantle.

    DOI: 10.2138/am-2019-6773

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  • Formation of dolomite catalyzed by sulfate-driven anaerobic oxidation of methane: Mineralogical and geochemical evidence from the northern South China Sea

    Yang Lu, Xiaoming Sun, Huifang Xu, Hiromi Konishi, Zhiyong Lin, Li Xu, Tingting Chen, Xinrong Hao, Hongfeng Lu, Jörn Peckmann

    American Mineralogist   103 ( 5 )   720 - 734   2018.5

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    Publishing type:Research paper (scientific journal)   Publisher:Mineralogical Society of America  

    DOI: 10.2138/am-2018-6226

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  • Microstructural characterization and in-situ sulfur isotopic analysis of silver-bearing sphalerite from the Edmond hydrothermal field, Central Indian Ridge

    Zhongwei Wu, Xiaoming Sun, Huifang Xu, Hiromi Konishi, Yan Wang, Yang Lu, Kaijun Cao, Chi Wang, Haoyang Zhou

    Ore Geology Reviews   92   318 - 347   2018.1

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.oregeorev.2017.11.024

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  • Protoenstatite: A new mineral in Oregon sunstones with “watermelon” colors

    Huifang Xu, Tina R. Hill, Hiromi Konishi, Gabriela Farfan

    American Mineralogist   102 ( 10 )   2146 - 2149   2017.10

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    Publishing type:Research paper (scientific journal)   Publisher:Mineralogical Society of America  

    DOI: 10.2138/am-2017-6186

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  • Microbial acceleration of aerobic pyrite oxidation at circumneutral <scp>pH</scp>

    E. Percak‐Dennett, S. He, B. Converse, H. Konishi, H. Xu, A. Corcoran, D. Noguera, C. Chan, A. Bhattacharyya, T. Borch, E. Boyd, E. E. Roden

    Geobiology   15 ( 5 )   690 - 703   2017.4

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    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    Abstract

    Pyrite (FeS<sub>2</sub>) is the most abundant sulfide mineral on Earth and represents a significant reservoir of reduced iron and sulfur both today and in the geologic past. In modern environments, oxidative transformations of pyrite and other metal sulfides play a key role in terrestrial element partitioning with broad impacts to contaminant mobility and the formation of acid mine drainage systems. Although the role of aerobic micro‐organisms in pyrite oxidation under acidic‐pH conditions is well known, to date there is very little known about the capacity for aerobic micro‐organisms to oxidize pyrite at circumneutral pH. Here, we describe two enrichment cultures, obtained from pyrite‐bearing subsurface sediments, that were capable of sustained cell growth linked to pyrite oxidation and sulfate generation at neutral pH. The cultures were dominated by two Rhizobiales species (Bradyrhizobium sp. and Mesorhizobium sp.) and a Ralstonia species. Shotgun metagenomic sequencing and genome reconstruction indicated the presence of Fe and S oxidation pathways in these organisms, and the presence of a complete Calvin–Benson–Bassham CO<sub>2</sub> fixation system in the Bradyrhizobium sp. Oxidation of pyrite resulted in thin (30–50 nm) coatings of amorphous Fe(III) oxide on the pyrite surface, with no other secondary Fe or S phases detected by electron microscopy or X‐ray absorption spectroscopy. Rates of microbial pyrite oxidation were approximately one order of magnitude higher than abiotic rates. These results demonstrate the ability of aerobic microbial activity to accelerate pyrite oxidation and expand the potential contribution of micro‐organisms to continental sulfide mineral weathering around the time of the Great Oxidation Event to include neutral‐pH environments. In addition, our findings have direct implications for the geochemistry of modern sedimentary environments, including stimulation of the early stages of acid mine drainage formation and mobilization of pyrite‐associated metals.

    DOI: 10.1111/gbi.12241

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    Other Link: https://onlinelibrary.wiley.com/doi/full-xml/10.1111/gbi.12241

  • Occurrences and distribution of “invisible” precious metals in sulfide deposits from the Edmond hydrothermal field, Central Indian Ridge

    Zhongwei Wu, Xiaoming Sun, Huifang Xu, Hiromi Konishi, Yan Wang, Chi Wang, Yingzhi Dai, Xiguang Deng, Miao Yu

    Ore Geology Reviews   79   105 - 132   2016.12

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.oregeorev.2016.05.006

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  • Role of nano-goethite in controlling U(VI) sorption-desorption in subsurface soil

    Hun Bok Jung, Huifang Xu, Hiromi Konishi, Eric E. Roden

    Journal of Geochemical Exploration   169   80 - 88   2016.10

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.gexplo.2016.07.014

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  • Nanoporous goethite controlling the mobility of uranium in saprolite subsoil: Long-term sorption and desorption experiments

    Jung, HB (Jung, Hun Bok, Xu, HF (Xu, Huifang, Konishi, H, onishi, Hiromi, Roden, E, Roden, Eric

    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY   252   2016.8

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  • Interstratification of graphene-like carbon layers within black talc from Southeastern China: Implications to sedimentary talc formation

    Chengxiang Li, Rucheng Wang, Huifang Xu, Xiancai Lu, Hiromi Konishi, Kun He

    American Mineralogist   101 ( 7 )   1668 - 1678   2016.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Walter de Gruyter GmbH  

    Large deposits of unusual black talc interstratified with dolostone layers of the late Neoproterozoic Dengying Formation were discovered in Guangfeng County, Jiangxi Province, southeastern China. The black talc ore exhibits primarily oolitic structures and consists mainly of talc (30-70 wt%), dolomite, and quartz, with trace amounts of pyrite and apatite. The ooids are composed of nearly pure black talc crystals, most of which consist of ultrafine nano-plates. The black talc contains small amounts of carbon, which causes the black coloring. Raman spectra and X-ray photoelectron spectroscopy (XPS) results indicate structural disorder and chemical impurities within bonds (e.g., sp3 hybridized carbon and C-O bonds) in the carbonaceous material, instead of perfectly structured graphite or graphene. Isolated graphene-like carbon interlayers are present in the talc nano-crystals, as shown by Z-contrast transmission electron microscope (TEM) imaging. Based on previous studies on Mg-silicate precipitation from surface water, we propose a sedimentary formation mechanism for the black talc, in which tetrahedral-octahedral-tetrahedral (T-O-T) layers of Mg-silicates, 1~2 unit-cells thick, co-precipitated with abundant organic matter derived from microorganisms thriving in locally Al-depleted sea water with high concentrations of Mg2+ and SiO2 (aq), in a shallow marine or lagoonal environment. The involvement of organic matter may have facilitated the precipitation of Mg-silicate. Further diagenesis and re-crystalliztion of the biomass-coated precursor resulted in the formation of graphene-like layers between neighboring talc nano-crystals with same orientation.

    DOI: 10.2138/am-2016-5600

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  • Interactions Between Fe(III)-Oxides and Fe(III)-Phyllosilicates During Microbial Reduction 1: Synthetic Sediments

    Tao Wu, Ravi K. Kukkadapu, Aron M. Griffin, Christopher A. Gorski, Hiromi Konishi, Huifang Xu, Eric E. Roden

    Geomicrobiology Journal   33 ( 9 )   793 - 806   2016.6

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    Publishing type:Research paper (scientific journal)   Publisher:Informa UK Limited  

    DOI: 10.1080/01490451.2015.1117546

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  • Natural occurrence of monoclinic Fe<sub>3</sub>S<sub>4</sub> nano-precipitates in pyrrhotite from the Sudbury ore deposit: a Z-contrast imaging and density functional theory study

    Huifang Xu, Zhizhang Shen, Hiromi Konishi

    Mineralogical Magazine   79 ( 2 )   377 - 385   2015.4

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    Publishing type:Research paper (scientific journal)   Publisher:Mineralogical Society  

    Abstract

    A monoclinic form of Fe<sub>3</sub>S<sub>4</sub>, a polymorph of cubic greigite, occurs as precipitates in a sample of pyrrhotite collected from the Sudbury ore deposit. The nano-crystal precipitates are in a topotaxial relationship with the host pyrrhotite-4C (Fe<sub>7</sub>S<sub>8</sub>). The precipitate and the host pyrrhotite have a coherent (001) interface. Half of the octahedral layers in the crystal structure are fully occupied by Fe, while the other half of the octahedral layers are occupied by Fe atoms and vacancies in an ordered manner along the a axis. The crystal structure of the Fe<sub>3</sub>S<sub>4</sub> nano-precipitates has monoclinic symmetry with a space group of I2/m. Its c dimension is 6% smaller than that of the host pyrrhotite due to the large number of vacancies in the structure. Fractional coordinates for S and Fe atoms within the unit cell are determined from Z-contrast images and density functional theory (DFT). The calculated results match the measured values very well. It is proposed that the monoclinic Fe<sub>3</sub>S<sub>4</sub> nano-precipitates formed through ordering of vacancies in pyrrhotite with a low Fe/S ratio (i.e. &lt;0.875) at low temperature.

    DOI: 10.1180/minmag.2015.079.2.15

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  • The catalytic effect of bound extracellular polymeric substances excreted by anaerobic microorganisms on Ca-Mg carbonate precipitation: Implications for the "dolomite problem"

    F. Zhang, H. Xu, E. S. Shelobolina, H. Konishi, B. Converse, Z. Shen, E. E. Roden

    American Mineralogist   100 ( 2-3 )   483 - 494   2015.2

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    Publishing type:Research paper (scientific journal)   Publisher:Mineralogical Society of America  

    DOI: 10.2138/am-2015-4999

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  • Si-magnetite nano-precipitates in silician magnetite from banded iron formation: Z-contrast imaging and ab initio study

    H. Xu, Z. Shen, H. Konishi

    American Mineralogist   99 ( 11-12 )   2196 - 2202   2014.11

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    Publishing type:Research paper (scientific journal)   Publisher:Mineralogical Society of America  

    DOI: 10.2138/am-2014-4964

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  • Crystal structure of Guinier-Preston zones in orthopyroxene: Z-contrast imaging and ab inito study

    H. Xu, Z. Shen, H. Konishi, G. Luo

    American Mineralogist   99 ( 10 )   2043 - 2048   2014.10

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    Publishing type:Research paper (scientific journal)   Publisher:Mineralogical Society of America  

    DOI: 10.2138/am-2014-4898

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  • Morphology and formation mechanism of pyrite induced by the anaerobic oxidation of methane from the continental slope of the NE South China Sea

    Mei Zhang, Hiromi Konishi, Huifang Xu, Xiaoming Sun, Hongfeng Lu, Daidai Wu, Nengyou Wu

    Journal of Asian Earth Sciences   92   293 - 301   2014.10

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.jseaes.2014.05.004

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  • Asphalt and asphaltite from the Yashiroda oil field, Niigata Prefecture, Japan

    Mitsuo Shimazu, Hideki Nishita, Hiromi Konishi, Yoshimi Takeshita

    The Journal of the Geological Society of Japan   120 ( 7 )   247 - 253   2014.7

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    Publishing type:Research paper (scientific journal)   Publisher:The Geological Society of Japan  

    DOI: 10.5575/geosoc.2014.0023

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  • Z-contrast imaging and ab initio study on "d" superstructure in sedimentary dolomite

    Z. Shen, H. Konishi, I. Szlufarska, P. E. Brown, H. Xu

    American Mineralogist   99 ( 7 )   1413 - 1419   2014.7

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    Publishing type:Research paper (scientific journal)   Publisher:Mineralogical Society of America  

    DOI: 10.2138/am.2014.4647

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  • Rapid control of phase growth by nanoparticles

    Lian-Yi Chen, Jia-Quan Xu, Hongseok Choi, Hiromi Konishi, Song Jin, Xiao-Chun Li

    Nature Communications   5 ( 1 )   2014.5

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    Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1038/ncomms4879

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    Other Link: http://www.nature.com/articles/ncomms4879

  • Crystal structures of laihunite and intermediate phases between laihunite-1M and fayalite: Z-contrast imaging and ab initio study

    H. Xu, Z. Shen, H. Konishi, P. Fu, I. Szlufarska

    American Mineralogist   99 ( 5-6 )   881 - 889   2014.5

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    Publishing type:Research paper (scientific journal)   Publisher:Mineralogical Society of America  

    DOI: 10.2138/am.2014.4691

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  • Iron Isotope Composition of Particles Produced by UV-Femtosecond Laser Ablation of Natural Oxides, Sulfides, and Carbonates

    Francois-Xavier d’Abzac, Brian L. Beard, Andrew D. Czaja, Hiromi Konishi, James J. Schauer, Clark M. Johnson

    Analytical Chemistry   85 ( 24 )   11885 - 11892   2013.12

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    Publishing type:Research paper (scientific journal)   Publisher:American Chemical Society (ACS)  

    DOI: 10.1021/ac402722t

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  • Testing the cation-hydration effect on the crystallization of Ca–Mg–CO <sub>3</sub> systems

    Jie Xu, Chao Yan, Fangfu Zhang, Hiromi Konishi, Huifang Xu, H. Henry Teng

    Proceedings of the National Academy of Sciences   110 ( 44 )   17750 - 17755   2013.10

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    Publishing type:Research paper (scientific journal)   Publisher:Proceedings of the National Academy of Sciences  

    Significance

    Magnesium-bearing carbonate minerals play critical roles in the health and function of the Earth system because they constitute a significant fraction of lithosphere carbon reservoir and build skeletal structures for the majority of marine invertebrate organisms. Despite wide occurrence, high-Mg and sole-Mg phases such as dolomite ([Ca,Mg]CO <sub>3</sub> ) and magnesite (MgCO <sub>3</sub> ) prove virtually impossible to be crystallized under ambient conditions. It has long been believed that Mg <sup>2+</sup> hydration is the cause for such a geological mystery. Here, we probe this hypothesis by investigating Ca–Mg–CO <sub>3</sub> precipitation in the absence of water and find direct proof suggesting the existence of a more intrinsic crystallization barrier. These findings provide a perspective augmenting our understanding in carbonate mineralogy, biomineralization, and mineral-carbonation processes.

    DOI: 10.1073/pnas.1307612110

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  • STEM investigation of exsolution lamellae and "c" reflections in Ca-rich dolomite from the Platteville Formation, western Wisconsin

    Z. Shen, H. Konishi, P. E. Brown, H. Xu

    American Mineralogist   98 ( 4 )   760 - 766   2013.3

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    Publishing type:Research paper (scientific journal)   Publisher:Mineralogical Society of America  

    DOI: 10.2138/am.2013.4184

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  • Natural occurrence of keatite precipitates in UHP clinopyroxene from the Kokchetav Massif: A TEM investigation

    T. R. Hill, H. Konishi, H. Xu

    American Mineralogist   98 ( 1 )   187 - 196   2012.12

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    Publishing type:Research paper (scientific journal)   Publisher:Mineralogical Society of America  

    DOI: 10.2138/am.2013.4170

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  • Nanoparticle-Induced Superior Hot Tearing Resistance of A206 Alloy

    Hongseok Choi, Woo-hyun Cho, Hiromi Konishi, Sindo Kou, Xiaochun Li

    Metallurgical and Materials Transactions A   44 ( 4 )   1897 - 1907   2012.11

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    Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1007/s11661-012-1531-8

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    Other Link: https://link.springer.com/article/10.1007/s11661-012-1531-8/fulltext.html

  • Dissolved sulfide-catalyzed precipitation of disordered dolomite: Implications for the formation mechanism of sedimentary dolomite

    Fangfu Zhang, Huifang Xu, Hiromi Konishi, Joshua M. Kemp, Eric E. Roden, Zhizhang Shen

    Geochimica et Cosmochimica Acta   97   148 - 165   2012.11

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.gca.2012.09.008

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  • Isolation and Microbial Reduction of Fe(III) Phyllosilicates from Subsurface Sediments

    Tao Wu, Evgenya Shelobolina, Huifang Xu, Hiromi Konishi, Ravi Kukkadapu, Eric E. Roden

    Environmental Science &amp; Technology   46 ( 21 )   11618 - 11626   2012.10

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    Publishing type:Research paper (scientific journal)   Publisher:American Chemical Society (ACS)  

    DOI: 10.1021/es302639n

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  • Microbial Lithotrophic Oxidation of Structural Fe(II) in Biotite

    Evgenya Shelobolina, Huifang Xu, Hiromi Konishi, Ravi Kukkadapu, Tao Wu, Marco Blöthe, Eric Roden

    Applied and Environmental Microbiology   78 ( 16 )   5746 - 5752   2012.8

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    Publishing type:Research paper (scientific journal)   Publisher:American Society for Microbiology  

    ABSTRACT

    Microorganisms are known to participate in the weathering of primary phyllosilicate minerals through the production of organic ligands and acids and through the uptake of products of weathering. Here we show that the lithotrophic Fe(II)-oxidizing, nitrate-reducing enrichment culture described by Straub et al. (K. L. Straub, M. Benz, B. Schink, and F. Widdel, Appl. Environ. Microbiol. 62:1458–1460, 1996) can grow via oxidation of structural Fe(II) in biotite, a Fe(II)-rich trioctahedral mica found in granitic rocks. Oxidation of silt/clay-sized biotite particles was detected by a decrease in extractable Fe(II) content and simultaneous nitrate reduction. Mössbauer spectroscopy confirmed structural Fe(II) oxidation. Approximately 1.5 × 10 <sup>7</sup> cells were produced per μmol of Fe(II) oxidized, in agreement with previous estimates of the growth yield of lithoautotrophic circumneutral-pH Fe(II)-oxidizing bacteria. Microbial oxidation of structural Fe(II) resulted in biotite alterations similar to those found in nature, including a decrease in the unit cell b dimension toward dioctahedral levels and Fe and K release. Structural Fe(II) oxidation may involve either direct enzymatic oxidation, followed by solid-state mineral transformation, or indirect oxidation as a result of the formation of aqueous Fe, followed by electron transfer from Fe(II) in the mineral to Fe(III) in solution. Although it is not possible to distinguish between these two mechanisms with available data, the complete absence of aqueous Fe in oxidation experiments favors the former alternative. The demonstration of microbial oxidation of structural Fe(II) suggests that microorganisms are directly responsible for the initial step in the weathering of biotite in granitic aquifers and the plant rhizosphere.

    DOI: 10.1128/aem.01034-12

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  • Novel nanoprocessing route for bulk graphene nanoplatelets reinforced metal matrix nanocomposites

    Lian-Yi Chen, Hiromi Konishi, Axel Fehrenbacher, Chao Ma, Jia-Quan Xu, Hongseok Choi, Hui-Fang Xu, Frank E. Pfefferkorn, Xiao-Chun Li

    Scripta Materialia   67 ( 1 )   29 - 32   2012.7

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.scriptamat.2012.03.013

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  • Redox Behavior of Uranium at the Nanoporous Aluminum Oxide-Water Interface: Implications for Uranium Remediation

    Hun Bok Jung, Maxim I. Boyanov, Hiromi Konishi, Yubing Sun, Bhoopesh Mishra, Kenneth M. Kemner, Eric E. Roden, Huifang Xu

    Environmental Science &amp; Technology   46 ( 13 )   7301 - 7309   2012.6

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    DOI: 10.1021/es2044163

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  • Piezoelectrochemical Effect: A New Mechanism for Azo Dye Decolorization in Aqueous Solution through Vibrating Piezoelectric Microfibers

    Kuang-Sheng Hong, Huifang Xu, Hiromi Konishi, Xiaochun Li

    The Journal of Physical Chemistry C   116 ( 24 )   13045 - 13051   2012.6

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    DOI: 10.1021/jp211455z

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  • Effect of core-shelled nanoparticles of carbon-coated nickel on magnesium

    Yi Sun, Hongseok Choi, Hiromi Konishi, Vadim Pikhovich, Robert Hathaway, Lianyi Chen, Xiaochun Li

    Materials Science and Engineering: A   546   284 - 290   2012.6

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    DOI: 10.1016/j.msea.2012.03.070

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  • Stability of Porous Platinum Nanoparticles: Combined In Situ TEM and Theoretical Study

    Shery L. Y. Chang, Amanda S. Barnard, Christian Dwyer, Thomas W. Hansen, Jakob B. Wagner, Rafal E. Dunin-Borkowski, Matthew Weyland, Hiromi Konishi, Huifang Xu

    The Journal of Physical Chemistry Letters   3 ( 9 )   1106 - 1110   2012.4

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    DOI: 10.1021/jz3001823

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  • Al2O3 nanoparticles induced simultaneous refinement and modification of primary and eutectic Si particles in hypereutectic Al–20Si alloy

    Hongseok Choi, Hiromi Konishi, Xiaochun Li

    Materials Science and Engineering: A   541   159 - 165   2012.4

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    DOI: 10.1016/j.msea.2012.01.131

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  • Polysaccharide-catalyzed nucleation and growth of disordered dolomite: A potential precursor of sedimentary dolomite

    F. Zhang, H. Xu, H. Konishi, E. S. Shelobolina, E. E. Roden

    American Mineralogist   97 ( 4 )   556 - 567   2012.3

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    DOI: 10.2138/am.2012.3979

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  • AZ91D/TiB<sub>2</sub> Nanocomposites Fabricated by Solidification Nanoprocessing

    Hongseok Choi, Yi Sun, Ben P. Slater, Hiromi Konishi, Xiaochun Li

    Advanced Engineering Materials   14 ( 5 )   291 - 295   2012.2

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    Abstract

    AZ91D, as one of the most widely used casting magnesium alloys, still suffers from inadequate mechanical performances for various applications. Nanoparticles could be used to form high‐performance magnesium matrix nanocomposites. Among all nanoparticles, TiB<sub>2</sub> has great potentials to enhance the mechanical property of AZ91D. This paper studies the microstructures and mechanical property of AZ91D‐TiB<sub>2</sub> nanocomposites fabricated through solidification nanoprocessing. TiB<sub>2</sub> nanoparticles with a diameter of 25 nm are effectively fed into the AZ91D melt through a newly developed automatic nanoparticle‐feeding system. Ultrasonic cavitation is used to disperse these nanoparticles in AZ91D melt for casting. With 2.7 wt% (about 1.0 vol%) of TiB<sub>2</sub> nanoparticles addition, the mechanical property of AZ91D is much enhanced (by 21, 16, and 48% for yield strength, tensile strength, and ductility, respectively). Microstructural analysis with optical microscope, SEM, and S/TEM show that α‐Mg grain and a network of massive brittle intermetallic phase (β‐Mg<sub>17</sub>Al<sub>12</sub>) are simultaneously refined and modified. Further study suggests that the enhancement of mechanical properties of AZ91D is attributed not only to primary phase grain refinement, but also to the modification of intermetallic β‐Mg<sub>17</sub>Al<sub>12</sub> by TiB<sub>2</sub> nanoparticles.

    DOI: 10.1002/adem.201100313

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  • Silician magnetite from the Dales Gorge Member of the Brockman Iron Formation, Hamersley Group, Western Australia

    J. M. Huberty, H. Konishi, P. R. Heck, J. H. Fournelle, J. W. Valley, H. Xu

    American Mineralogist   97 ( 1 )   26 - 37   2012.1

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    DOI: 10.2138/am.2012.3864

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  • Isolation of Phyllosilicate–Iron Redox Cycling Microorganisms from an Illite–Smectite Rich Hydromorphic Soil

    Evgenya Shelobolina, Hiromi Konishi, Huifang Xu, Jason Benzine, Mai Yia Xiong, Tao Wu, Marco Blöthe, Eric Roden

    Frontiers in Microbiology   3   2012

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    DOI: 10.3389/fmicb.2012.00134

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  • Effect of Combined Addition of Cu and Aluminum Oxide Nanoparticles on Mechanical Properties and Microstructure of Al-7Si-0.3Mg Alloy

    Hongseok Choi, Milton Jones, Hiromi Konishi, Xiaochun Li

    Metallurgical and Materials Transactions A   43 ( 2 )   738 - 746   2011.9

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    DOI: 10.1007/s11661-011-0905-7

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  • Lead coprecipitation with iron oxyhydroxide nano-particles

    Peng Lu, Noel T. Nuhfer, Shelly Kelly, Qin Li, Hiromi Konishi, Erika Elswick, Chen Zhu

    Geochimica et Cosmochimica Acta   75 ( 16 )   4547 - 4561   2011.8

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    DOI: 10.1016/j.gca.2011.05.035

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  • Nano-sized graphitic carbon in authigenic tube pyrites from offshore southwest Taiwan, South China Sea, and its implication for tracing gas hydrate

    Mei Zhang, XiaoMing Sun, Li Xu, HuiFang Xu, Hirom Konishi, Yang Lu, HongFeng Lu, ZhongWei Wu

    Chinese Science Bulletin   56 ( 19 )   2037 - 2043   2011.6

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    DOI: 10.1007/s11434-011-4527-7

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  • Iron isotope fractionation during microbial dissimilatory iron oxide reduction in simulated Archaean seawater

    E. M. PERCAK‐DENNETT, B. L. BEARD, H. XU, H. KONISHI, C. M. JOHNSON, E. E. RODEN

    Geobiology   9 ( 3 )   205 - 220   2011.4

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    Abstract

    The largest Fe isotope excursion yet measured in marine sedimentary rocks occurs in shales, carbonates, and banded iron formations of Neoarchaean and Paleoproterozoic age. The results of field and laboratory studies suggest a potential role for microbial dissimilatory iron reduction (DIR) in producing this excursion. However, most experimental studies of Fe isotope fractionation during DIR have been conducted in simple geochemical systems, using pure Fe(III) oxide substrates that are not direct analogues to phases likely to have been present in Precambrian marine environments. In this study, Fe isotope fractionation was investigated during microbial reduction of an amorphous Fe(III) oxide–silica coprecipitate in anoxic, high‐silica, low‐sulphate artificial Archaean seawater at 30 °C to determine if such conditions alter the extent of reduction or isotopic fractionations relative to those observed in simple systems. The Fe(III)–Si coprecipitate was highly reducible (c. 80% reduction) in the presence of excess acetate. The coprecipitate did not undergo phase conversion (e.g. to green rust, magnetite or siderite) during reduction. Iron isotope fractionations suggest that rapid and near‐complete isotope exchange took place among all Fe(II) and Fe(III) components, in contrast to previous work on goethite and hematite, where exchange was limited to the outer few atom layers of the substrate. Large quantities of low‐δ<sup>56</sup>Fe Fe(II) (aqueous and solid phase) were produced during reduction of the Fe(III)–Si coprecipitate. These findings shed new light on DIR as a mechanism for producing Fe isotope variations observed in Neoarchaean and Paleoproterozoic marine sedimentary rocks.

    DOI: 10.1111/j.1472-4669.2011.00277.x

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  • Morphology mapping of platinum catalysts over the entire nanoscale

    A. S. Barnard, H. Konishi, H. F. Xu

    Catalysis Science &amp; Technology   1 ( 8 )   1440 - 1440   2011

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    DOI: 10.1039/c1cy00238d

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  • Nanostructures of Natural Iron Oxide Nanoparticles

    H. Konishi, H. F. Xu, H. B. Guo

    Nature’s Nanostructures   2011

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  • A relationship between d104 value and composition in the calcite-disordered dolomite solid-solution series

    F. Zhang, H. Xu, H. Konishi, E. E. Roden

    American Mineralogist   95 ( 11-12 )   1650 - 1656   2010.11

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    DOI: 10.2138/am.2010.3414

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  • Extracellular electron transfer through microbial reduction of solid-phase humic substances

    Eric E. Roden, Andreas Kappler, Iris Bauer, Jie Jiang, Andrea Paul, Reinhard Stoesser, Hiromi Konishi, Huifang Xu

    Nature Geoscience   3 ( 6 )   417 - 421   2010.5

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    DOI: 10.1038/ngeo870

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  • Microbial production of isotopically light iron(II) in a modern chemically precipitated sediment and implications for isotopic variations in ancient rocks

    G. E. TANGALOS, B. L. BEARD, C. M. JOHNSON, C. N. ALPERS, E. S. SHELOBOLINA, H. XU, H. KONISHI, E. E. RODEN

    Geobiology   8 ( 3 )   197 - 208   2010.5

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    Abstract

    The inventories and Fe isotope composition of aqueous Fe(II) and solid‐phase Fe compounds were quantified in neutral‐pH, chemically precipitated sediments downstream of the Iron Mountain acid mine drainage site in northern California, USA. The sediments contain high concentrations of amorphous Fe(III) oxyhydroxides [Fe(III)<sub>am</sub>] that allow dissimilatory iron reduction (DIR) to predominate over Fe–S interactions in Fe redox transformation, as indicated by the very low abundance of Cr(II)‐extractable reduced inorganic sulfur compared with dilute HCl‐extractable Fe. δ<sup>56</sup>Fe values for bulk HCl‐ and HF‐extractable Fe were ≈ 0. These near‐zero bulk δ<sup>56</sup>Fe values, together with the very low abundance of dissolved Fe in the overlying water column, suggest that the pyrite Fe source had near‐zero δ<sup>56</sup>Fe values, and that complete oxidation of Fe(II) took place prior to deposition of the Fe(III) oxide‐rich sediment. Sediment core analyses and incubation experiments demonstrated the production of millimolar quantities of isotopically light (δ<sup>56</sup>Fe ≈ −1.5 to −0.5‰) aqueous Fe(II) coupled to partial reduction of Fe(III)<sub>am</sub> by DIR. Trends in the Fe isotope composition of solid‐associated Fe(II) and residual Fe(III)<sub>am</sub> are consistent with experiments with synthetic Fe(III) oxides, and collectively suggest an equilibrium Fe isotope fractionation between aqueous Fe(II) and Fe(III)<sub>am</sub> of approximately −2‰. These Fe(III) oxide‐rich sediments provide a model for early diagenetic processes that are likely to have taken place in Archean and Paleoproterozoic marine sediments that served as precursors for banded iron formations. Our results suggest pathways whereby DIR could have led to the formation of large quantities of low‐δ<sup>56</sup>Fe minerals during BIF genesis.

    DOI: 10.1111/j.1472-4669.2010.00237.x

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  • HRTEM investigation of trilling todorokite and nano-phase Mn-oxides in manganese dendrites

    H. Xu, T. Chen, H. Konishi

    American Mineralogist   95 ( 4 )   556 - 562   2010.3

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    DOI: 10.2138/am.2010.3211

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  • Direct Water Splitting Through Vibrating Piezoelectric Microfibers in Water

    Kuang-Sheng Hong, Huifang Xu, Hiromi Konishi, Xiaochun Li

    The Journal of Physical Chemistry Letters   1 ( 6 )   997 - 1002   2010.3

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    DOI: 10.1021/jz100027t

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  • High-resolution TEM study of jimthompsonite, chesterite, and chain-width disorder in Archean ultramafic rocks from Isua, West Greenland

    H. Konishi, H. Xu, R. F. Dymek

    American Mineralogist   95 ( 1 )   73 - 80   2009.12

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    DOI: 10.2138/am.2010.3212

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  • Strong, Ductile Magnesium-Zinc Nanocomposites

    Michael De Cicco, Hiromi Konishi, Guoping Cao, Hong Seok Choi, Lih-Sheng Turng, John H. Perepezko, Sindo Kou, Roderic Lakes, Xiaochun Li

    Metallurgical and Materials Transactions A   40 ( 12 )   3038 - 3045   2009.10

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    DOI: 10.1007/s11661-009-0013-0

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  • Generation of banded iron formations by internal dynamics and leaching of oceanic crust

    Yifeng Wang, Huifang Xu, Enrique Merino, Hiromi Konishi

    Nature Geoscience   2 ( 11 )   781 - 784   2009.10

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    DOI: 10.1038/ngeo652

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  • U(VI) Sequestration in Hydroxyapatite Produced by Microbial Glycerol 3-Phosphate Metabolism

    Evgenya S. Shelobolina, Hiromi Konishi, Huifang Xu, Eric E. Roden

    Applied and Environmental Microbiology   75 ( 18 )   5773 - 5778   2009.9

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    ABSTRACT

    Previous studies have demonstrated the potential for removal of U(VI) from solution via precipitation of U(VI)-bearing calcium-phosphate (Ca-P) minerals coupled to microbial hydrolysis of glycerol phosphate compounds. We evaluated this process in circumneutral-pH groundwater from Area 2 of the U.S. Department of Energy Field Research Center at Oak Ridge National Laboratory. Area 2 groundwater contains high concentrations of dissolved calcium (ca. 4 mM), and thus, release of phosphate during glycerol phosphate metabolism has the potential to create conditions favorable for U(VI) sequestration in Ca-P minerals. Microbial enumeration and isolation studies verified the presence of aerobic and nitrate-reducing glycerol 3-phosphate (G3P)-metabolizing microorganisms in Area 2 sediments. Coprecipitation of U(VI) with Ca-P minerals coupled to microbial G3P hydrolysis was demonstrated in artificial groundwater under aerobic and nitrate-reducing conditions. Transmission electron microscopy analysis and mineral-washing experiments demonstrated that U(VI) was incorporated into the structure of the insoluble Ca-P mineral hydroxyapatite [Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>OH]. Our results support the idea that U(VI) can be effectively removed from solution in contaminated aquifers through stimulation of microbial organophosphate metabolism.

    DOI: 10.1128/aem.00628-09

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  • Coupled alkali-feldspar dissolution and secondary mineral precipitation in batch systems: 1. New experiments at 200 °C and 300 bars

    Qi Fu, Peng Lu, Hiromi Konishi, Robert Dilmore, Huifang Xu, W.E. Seyfried, Chen Zhu

    Chemical Geology   258 ( 3-4 )   125 - 135   2009.1

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    DOI: 10.1016/j.chemgeo.2008.09.014

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  • Study on tensile properties and microstructure of cast AZ91D/AlN nanocomposites

    G. Cao, H. Choi, J. Oportus, H. Konishi, X. Li

    Materials Science and Engineering: A   494 ( 1-2 )   127 - 131   2008.10

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    DOI: 10.1016/j.msea.2008.04.070

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  • Mg–6Zn/1.5%SiC nanocomposites fabricated by ultrasonic cavitation-based solidification processing

    G. Cao, H. Choi, H. Konishi, S. Kou, R. Lakes, X. Li

    Journal of Materials Science   43 ( 16 )   5521 - 5526   2008.8

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    DOI: 10.1007/s10853-008-2785-9

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  • Surface chemistry and stability of nanostructured materials in natural aquatic environments

    Wang, YF, Wang, Yifeng, Gao, H, Gao, H, Xu, H (Xu, H, Siegel, M, Siegel, M, Konishi, H, ish

    GEOCHIMICA ET COSMOCHIMICA ACTA   72 ( 12 )   A1002 - A1002   2008.7

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  • Mechanical properties and microstructure of SiC-reinforced Mg-(2,4)Al-1Si nanocomposites fabricated by ultrasonic cavitation based solidification processing

    G. Cao, H. Konishi, X. Li

    Materials Science and Engineering: A   486 ( 1-2 )   357 - 362   2008.7

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    DOI: 10.1016/j.msea.2007.09.054

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  • Mechanical Properties and Microstructure of Mg∕SiC Nanocomposites Fabricated by Ultrasonic Cavitation Based Nanomanufacturing

    Guoping Cao, Hiromi Konishi, Xiaochun Li

    Journal of Manufacturing Science and Engineering   130 ( 3 )   2008.5

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    Magnesium, the lightest structural metal, is of significance to improve energy efficiency in various applications. Mg∕SiC nanocomposites were successfully fabricated by ultrasonic cavitation based dispersion of SiC nanoparticles in Mg melts. As compared to pure magnesium, the mechanical properties including tensile strength and yield strength of the Mg∕SiC nanocomposites were improved significantly, while the good ductility of pure Mg was retained. The grain size of the pure magnesium was refined significantly when SiC nanoparticles were dispersed in the Mg matrix. In the microstructure of Mg∕SiC nanocomposites, while there were still some SiC microclusters, most of the SiC nanoparticles were dispersed very well. Transmission electron microscopy study of the interface between SiC nanoparticles and magnesium matrix indicates that SiC nanoparticles bond well with Mg without forming an intermediate phase.

    DOI: 10.1115/1.2823086

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  • Tensile Properties and Microstructure of SiC Nanoparticle–Reinforced Mg-4Zn Alloy Fabricated by Ultrasonic Cavitation–Based Solidification Processing

    G. Cao, J. Kobliska, H. Konishi, X. Li

    Metallurgical and Materials Transactions A   39 ( 4 )   880 - 886   2008.2

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    DOI: 10.1007/s11661-007-9453-6

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  • Proto-polymorphs of jimthompsonite and chesterite in contact-metamorphosed serpentinites from Japan

    H. Konishi, P. R. Buseck, H. Xu, X. Li

    American Mineralogist   93 ( 2-3 )   351 - 359   2008.2

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    DOI: 10.2138/am.2008.2637

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  • Recent Developments on Ultrasonic Cavitation Based Solidification Processing of Bulk Magnesium Nanocomposites

    G. Cao, H. Konishi, X. Li

    International Journal of Metalcasting   2 ( 1 )   57 - 65   2008.1

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    DOI: 10.1007/bf03355422

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  • Perovskite hollow cubes: morphological control, three-dimensional twinning and intensely enhanced photoluminescence

    Xianfeng Yang, Ian D. Williams, Jian Chen, Jing Wang, Huifang Xu, Hiromi Konishi, Yuexiao Pan, Chaolun Liang, Mingmei Wu

    Journal of Materials Chemistry   18 ( 30 )   3543 - 3543   2008

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    DOI: 10.1039/b808396g

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  • Embedding of micro thin film strain sensors in sapphire by diffusion bonding

    Hongseok Choi, Hiromi Konishi, Huifang Xu, Xiaochun Li

    Journal of Micromechanics and Microengineering   17 ( 11 )   2248 - 2252   2007.10

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    Publishing type:Research paper (scientific journal)   Publisher:IOP Publishing  

    DOI: 10.1088/0960-1317/17/11/011

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  • Structural and chemical changes in In-oxide nano-crystals: XRD and HRTEM study

    Xu, HF (Xu, Huifang, Yeredla, RR (Yeredla, Rakesh R, Konishi, H, onishi, Hiromi, Narayanaswamy, A, Narayanaswamy, Arun, Peng, XG, Pen, Xiaogang, Li, XC (Li, Xiaochun

    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY   233   511 - 511   2007.3

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  • Investigation of enhanced photocatalytic reduction and oxidation of titanium oxide nanotubes

    Xu, HF (Xu, Huifang, Konishi, H, onishi, Hiromi, Yeredla, RR (Yeredla, Rakesh R, Wang, YF, Wang, Yif

    233   2007.3

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  • Importance of c-Type cytochromes for U(VI) reduction by Geobacter sulfurreducens

    Evgenya S Shelobolina, Maddalena V Coppi, Anton A Korenevsky, Laurie N DiDonato, Sara A Sullivan, Hiromi Konishi, Huifang Xu, Ching Leang, Jessica E Butler, Byoung-Chan Kim, Derek R Lovley

    BMC Microbiology   7 ( 1 )   2007.3

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    Abstract

    Background

    In order to study the mechanism of U(VI) reduction, the effect of deletingc-type cytochrome genes on the capacity ofGeobacter sulfurreducensto reduce U(VI) with acetate serving as the electron donor was investigated.

    Results

    The ability of severalc-type cytochrome deficient mutants to reduce U(VI) was lower than that of the wild type strain. Elimination of two confirmed outer membrane cytochromes and two putative outer membrane cytochromes significantly decreased (ca. 50–60%) the ability ofG. sulfurreducensto reduce U(VI). Involvement in U(VI) reduction did not appear to be a general property of outer membrane cytochromes, as elimination of two other confirmed outer membrane cytochromes, OmcB and OmcC, had very little impact on U(VI) reduction. Among the periplasmic cytochromes, only MacA, proposed to transfer electrons from the inner membrane to the periplasm, appeared to play a significant role in U(VI) reduction. A subpopulation of both wild type and U(VI) reduction-impaired cells, 24–30%, accumulated amorphous uranium in the periplasm. Comparison of uranium-accumulating cells demonstrated a similar amount of periplasmic uranium accumulation in U(VI) reduction-impaired and wild typeG. sulfurreducens. Assessment of the ability of the various suspensions to reduce Fe(III) revealed no correlation between the impact of cytochrome deletion on U(VI) reduction and reduction of Fe(III) hydroxide and chelated Fe(III).

    Conclusion

    This study indicates thatc-type cytochromes are involved in U(VI) reduction byGeobacter sulfurreducens. The data provide new evidence for extracellular uranium reduction byG. sulfurreducensbut do not rule out the possibility of periplasmic uranium reduction. Occurrence of U(VI) reduction at the cell surface is supported by the significant impact of elimination of outer membrane cytochromes on U(VI) reduction and the lack of correlation between periplasmic uranium accumulation and the capacity for uranium reduction. Periplasmic uranium accumulation may reflect the ability of uranium to penetrate the outer membrane rather than the occurrence of enzymatic U(VI) reduction. Elimination of cytochromes rarely had a similar impact on both Fe(III) and U(VI) reduction, suggesting that there are differences in the routes of electron transfer to U(VI) and Fe(III). Further studies are required to clarify the pathways leading to U(VI) reduction inG. sulfurreducens.

    DOI: 10.1186/1471-2180-7-16

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  • Comparative Sol–Hydro(Solvo)thermal Synthesis of TiO<sub>2</sub> Nanocrystals

    Xianfeng Yang, Hiromi Konishi, Huifang Xu, Mingmei Wu

    European Journal of Inorganic Chemistry   2006 ( 11 )   2229 - 2235   2006.5

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    Abstract

    Three small inorganic compounds [acetic acid (CH<sub>3</sub>COOH), nitric acid (HNO<sub>3</sub>), and hydrochloric acid (HCl)] andfive small organic compounds [n‐butyl alcohol (CH<sub>3</sub>CH<sub>2</sub>CH<sub>2</sub>CH<sub>2</sub>OH), 1,2‐propanediol (CH<sub>2</sub>OHCHOHCH<sub>3</sub>), propane‐1,3‐dicarboxylic acid (HOOCCH<sub>2</sub>COOH), butane‐1,4‐dicarboxylic acid (HOOCCH<sub>2</sub>CH<sub>2</sub>COOH), and ethylenediamine (H<sub>2</sub>NCH<sub>2</sub>CH<sub>2</sub>NH<sub>2</sub>)] with different donors (Cl<sup>–</sup>, NO<sub>3</sub><sup>–</sup>, OH, COO<sup>–</sup>, and NH<sub>2</sub>) are used respectively and comparatively in different reaction media for tailoring the sol–hydrothermal synthesis of TiO<sub>2</sub> nanocrystals at a specific reaction temperature and/or for different reaction times. Both anatase and rutile with a variety of nanostructures such as nanocubes, nanorods, nanoneedles, and their self‐assembled nanospheres are selectively grown. Well‐defined and crystalline anatase nanocrystals with a narrow size distribution are prepared in the presence of n‐butyl alcohol. With the use of HCl, nanoneedles and their assembled nanospheres of phase‐pure rutile are obtained under much less drastic conditions, even at 100 °C and for only two hours. The effects of the reaction media, synthesis temperatures, and aging times on the structures and shapes of the products are investigated in detail by powder X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2006)

    DOI: 10.1002/ejic.200500855

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  • Photocatalytic Oxidation of a Volatile Organic Component of Acetaldehyde Using Titanium Oxide Nanotubes

    Huifang Xu, Ganesh Vanamu, Ziming Nie, Hiromi Konishi, Rakesh Yeredla, Jonathan Phillips, Yifeng Wang

    Journal of Nanomaterials   2006 ( 1 )   2006.1

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    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    Titanium oxide nanotubes are prepared and treated with Au (Au/nanotube sample) and Pt (Pt/nanotube sample), and the photoactivity of these catalysts compared to a standard Degussa P25 photocatalyst is investigated. The samples were analyzed using X‐ray diffraction, field emission gun scanning transmission electron microscopy (STEM). Both high‐resolution TEM images and high‐angle annular dark‐field (HAAD) images were recorded for the specimens. Oxidation of acetaldehyde was used to test the efficiency of the catalysts. Nanotube samples showed better photoactivity than the standard P25, because the P25 titania deactivates quickly. Enhanced reactivity of the nanotube is related to surface charge polarity developed on outer and inner surfaces due to the difference in overlap of oxygen anions that resulted from curving of octahedral sheets. A tentative and qualitative surface polarity model is proposed for enhancing electron‐hole pair separation. The inner surface benefits reduction; whereas, the outer surface benefits oxidation reactions. Both the metal identity and the size of the metal particles in the nanotubes affected the photocatalytic activity. Specifically, the addition of platinum increased the activity significantly, and increased the total yield. The addition of gold had lesser impact compared to the platinum. Formation of Pt large nanoparticles on the nanotube surfaces reduces the oxidation reactivity.

    DOI: 10.1155/jnm/2006/78902

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    Other Link: https://onlinelibrary.wiley.com/doi/pdf/10.1155/JNM/2006/78902

  • Morphological and Chemical/Physical Characterization of Fe-Doped Synthetic Chrysotile Nanotubes

    E. Foresti, M. F. Hochella, H. Kornishi, I. G. Lesci, A. S. Madden, N. Roveri, H. Xu

    Advanced Functional Materials   15 ( 6 )   1009 - 1016   2005.6

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    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    DOI: 10.1002/adfm.200400355

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  • Chromium(III) Oxidation Coupled with Microbially Mediated Mn(II) Oxidation

    Youxian Wu, Baolin Deng, Huifang Xu, Hiromi Kornishi

    Geomicrobiology Journal   22 ( 3-4 )   161 - 170   2005.4

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    Publishing type:Research paper (scientific journal)   Publisher:Informa UK Limited  

    DOI: 10.1080/01490450590945997

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  • 2111 biopyribole intermediate between pyroxene and amphibole: Artifact or natural product?

    Konishi, H, Konishi, Alviola, R, Alviola, R, Buseck, PR, Buseck, P

    AMERICAN MINERALOGIST   89 ( 1 )   15 - 19   2004.1

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  • Crystal structure of protoanthophyllite: A new mineral from the Takase ultramafic complex, Japan

    Hiromi konishi, Thomas L. Groy, István dódony, Ritsuro Miyawaki, Satoshi Matsubara, Peter R. Buseck

    American Mineralogist   88 ( 11-12 )   1718 - 1723   2003.11

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    Publishing type:Research paper (scientific journal)   Publisher:Mineralogical Society of America  

    DOI: 10.2138/am-2003-11-1212

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  • Seafloor bioalteration of sulfide minerals: results from in situ incubation studies

    Katrina J. Edwards, Thomas M. McCollom, Hiromi Konishi, Peter R. Buseck

    Geochimica et Cosmochimica Acta   67 ( 15 )   2843 - 2856   2003.8

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/s0016-7037(03)00089-9

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  • Protoanthophyllite from three metamorphosed serpentinites

    Konishi, H, Konishi, H, Dódony, I, Buseck, PR, Buseck, P

    AMERICAN MINERALOGIST   87 ( 8-9 )   1096 - 1103   2002.8

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  • New occurrences of non-classical pyriboles formed during ocean-floor and regional metamorphism: estimated PT conditions of formation

    Akai, J, Akai, J, Chiba, A, Chiba, A, Konishi, H, onishi, H, Komatsu, M, Matsubara, S, Ma, subara

    EUROPEAN JOURNAL OF MINERALOGY   9 ( 6 )   1237 - 1255   1997.11

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  • A transmission electron microscopic study of dusty plagioclase in calc-alkaline andesite from the Oze-Hiuchigatake volcano, central Japan

    H. Konishi, J. Akai

    Mineralogy and Petrology   53 ( 1-3 )   173 - 187   1995.3

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    Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1007/bf01171955

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    Other Link: http://link.springer.com/article/10.1007/BF01171955/fulltext.html

  • DEPOLYMERIZED PYRIBOLE STRUCTURES DERIVED FROM TALC BY HEATING

    KONISHI, H, KONISHI, H, AKAI, J, AKAI

    PHYSICS AND CHEMISTRY OF MINERALS   17 ( 7 )   569 - 582   1991

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  • HRTEM OBSERVATION OF NEW COMPLEX POLYTYPE OF BIOTITE FROM DACITES IN HIGASHIYAMA HILLS, NIIGATA, CENTRAL JAPAN

    HIROMI KONISHI, JUNJI AKAI

    Clay Science   8   25 - 30   1990.10

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  • Finding of osumilite and andalusite from the Pliocene subaqueous ash layer in Niigata Prefecture, Central Japan

    KATSUKI KUROKAWA, HIROMI KONISHI, YOSHIMI FUJIWARA

    J. Min. Petr. Econ. Geol.   85   495 - 501   1990

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Teaching Experience (researchmap)

Teaching Experience

  • 理学スタディ・スキルズ

    2022
    Institution name:新潟大学

  • 鉱物科学特論

    2021
    Institution name:新潟大学

  • 論文講読演習

    2020
    Institution name:新潟大学

  • 課題研究(地質科学)

    2020
    Institution name:新潟大学

  • 地質調査法実習III

    2019
    Institution name:新潟大学

  • 鉱物学C

    2019
    Institution name:新潟大学

  • 大型機器分析技術

    2019
    -
    2021
    Institution name:新潟大学

  • 野外実習A

    2019
    -
    2020
    Institution name:新潟大学

  • 地質調査法I

    2018
    Institution name:新潟大学

  • 地質調査法実習II

    2018
    Institution name:新潟大学

  • 地質調査法実習I

    2018
    Institution name:新潟大学

  • 鉱物・岩石学入門

    2018
    Institution name:新潟大学

  • 地質調査法II

    2018
    Institution name:新潟大学

  • 地学基礎実習a

    2017
    Institution name:新潟大学

  • 地質学入門b

    2017
    Institution name:新潟大学

  • 理学スタディ・スキルズ

    2017
    -
    2022
    Institution name:新潟大学

  • 課題研究

    2017
    -
    2020
    Institution name:新潟大学

  • フィールド体験実習

    2017
    Institution name:新潟大学

  • 地学基礎実習b

    2017
    Institution name:新潟大学

  • 野外実習II

    2016
    -
    2017
    Institution name:新潟大学

  • 自然科学総論Ⅴ

    2015
    -
    2016
    Institution name:新潟大学

  • 地学概論B

    2015
    Institution name:新潟大学

  • 論文作成演習M

    2015
    Institution name:新潟大学

  • 地球科学特定研究Dc

    2015
    Institution name:新潟大学

  • 電子線結晶学

    2014
    Institution name:新潟大学

  • 地学概論

    2014
    -
    2020
    Institution name:新潟大学

  • 野外実習III

    2014
    -
    2018
    Institution name:新潟大学

  • 鉱物科学特論

    2014
    -
    2018
    Institution name:新潟大学

  • 中間発表D

    2014
    -
    2015
    Institution name:新潟大学

  • 地球科学特別講義II

    2014
    Institution name:新潟大学

  • 地球科学特定研究Db

    2014
    Institution name:新潟大学

  • 鉱物学A

    2013
    Institution name:新潟大学

  • 科学・技術と社会

    2013
    Institution name:新潟大学

  • 鉱物結晶学実験

    2013
    Institution name:新潟大学

  • 地球物理学

    2013
    Institution name:新潟大学

  • 鉱物学B

    2013
    Institution name:新潟大学

  • セミナー

    2013
    -
    2020
    Institution name:新潟大学

  • 地史学原理

    2013
    -
    2017
    Institution name:新潟大学

  • 地学実験

    2013
    -
    2017
    Institution name:新潟大学

  • 課題研究(地質科学科)

    2013
    -
    2016
    Institution name:新潟大学

  • 地質調査法基礎 I

    2013
    -
    2016
    Institution name:新潟大学

  • 野外実習基礎

    2013
    -
    2016
    Institution name:新潟大学

  • 地球科学演習D

    2013
    -
    2015
    Institution name:新潟大学

  • 地質調査法基礎 II

    2013
    -
    2014
    Institution name:新潟大学

  • 地球科学特定研究Mb

    2013
    Institution name:新潟大学

  • 地球科学演習Mb

    2013
    Institution name:新潟大学

  • 学術発表演習D

    2013
    Institution name:新潟大学

  • 中間発表M

    2013
    Institution name:新潟大学

  • ナノ鉱物組織学

    2013
    Institution name:新潟大学

  • 鉱物生成論

    2013
    Institution name:新潟大学

  • 地球科学特定研究Da

    2013
    Institution name:新潟大学

  • 岩石学実験I

    2013
    Institution name:新潟大学

  • 地球科学演習Ma

    2012
    -
    2015
    Institution name:新潟大学

  • 地球科学特定研究Ma

    2012
    -
    2015
    Institution name:新潟大学

  • 学術発表演習M

    2012
    Institution name:新潟大学

  • リサーチキャンプ

    2012
    Institution name:新潟大学

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