研究者詳細 - 国広　卓也

論文 - 国広　卓也

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Unraveling the Cr Isotopes of Ryugu: An Accurate Aqueous Alteration Age and the Least Thermally Processed Solar System Material

Ryoji Tanaka, Dilan M. Ratnayake, Tsutomu Ota, Noah Miklusicak, Tak Kunihiro, Christian Potiszil, Chie Sakaguchi, Katsura Kobayashi, Hiroshi Kitagawa, Masahiro Yamanaka, Masanao Abe, Akiko Miyazaki, Aiko Nakato, Satoru Nakazawa, Masahiro Nishimura, Tatsuaki Okada, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Yuichi Tsuda, Tomohiro Usui, Sei-ichiro Watanabe, Toru Yada, Kasumi Yogata, Makoto Yoshikawa, Eizo Nakamura

The Astrophysical Journal 965 ( 1 ) 52 - 52 2024年4月

掲載種別：研究論文（学術雑誌）出版者・発行元：American Astronomical Society

Abstract

The analysis of samples returned from the C-type asteroid Ryugu has drastically advanced our knowledge of the evolution of early solar system materials. However, no consensus has been obtained on the chronological data, which is important for understanding the evolution of the asteroid Ryugu. Here, the aqueous alteration age of Ryugu particles was determined by the Mn–Cr method using bulk samples, yielding an age of 4.13 + 0.62/−0.55 Myr after the formation of Ca–Al-rich inclusions (CAI). The age corresponds to 4563.17 + 0.60/−0.67 Myr ago. The higher ⁵⁵Mn/⁵²Cr, ε ⁵⁴Cr, and initial ε ⁵³Cr values of the Ryugu samples relative to any carbonaceous chondrite samples implies that its progenitor body formed from the least thermally processed precursors in the outermost region of the protoplanetary disk. Despite accreting at different distances from the Sun, the hydrous asteroids (Ryugu and the parent bodies of CI, CM, CR, and ungrouped C2 meteorites) underwent aqueous alteration during a period of limited duration (3.8 ± 1.8 Myr after CAI). These ages are identical to the crystallization age of the carbonaceous achondirtes NWA 6704/6693 within the error. The ε ⁵⁴Cr and initial ε ⁵³Cr values of Ryugu and NWA 6704/6693 are also identical, while they show distinct Δ'¹⁷O values. This suggests that the precursors that formed the progenitor bodies of Ryugu and NWA 6703/6693 were formed in close proximity and experienced a similar degree of thermal processing in the protosolar nebula. However, the progenitor body of Ryugu was formed by a higher ice/dust ratio, than NWA6703/6693, in the outer region of the protoplanetary disk.

DOI： 10.3847/1538-4357/ad276a

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その他リンク： https://iopscience.iop.org/article/10.3847/1538-4357/ad276a/pdf

The Formation of a Rubble Pile Asteroid: Insights from the Asteroid Ryugu 査読

Tsutomu Ota, Christian Potiszil, Katsura Kobayashi, Ryoji Tanaka, Hiroshi Kitagawa, Tak Kunihiro, Chie Sakaguchi, Masahiro Yamanaka, Eizo Nakamura

Universe 2023年6月

Organic Matter in the Asteroid Ryugu: What We Know So Far 招待査読

Christian Potiszil, Masahiro Yamanaka, Chie Sakaguchi, Tsutomu Ota, Hiroshi Kitagawa, Tak Kunihiro, Ryoji Tanaka, Katsura Kobayashi, Eizo Nakamura

Life 2023年6月

Spectroscopic and Biophysical Methods to Determine Differential Salt‐Uptake by Primitive Membraneless Polyester Microdroplets

Chen Chen, Ruiqin Yi, Motoko Igisu, Chie Sakaguchi, Rehana Afrin, Christian Potiszil, Tak Kunihiro, Katsura Kobayashi, Eizo Nakamura, Yuichiro Ueno, André Antunes, Anna Wang, Kuhan Chandru, Jihua Hao, Tony Z. Jia

Small Methods 2023年5月

掲載種別：研究論文（学術雑誌）出版者・発行元：Wiley

Abstract

α‐Hydroxy acids are prebiotic monomers that undergo dehydration synthesis to form polyester gels, which assemble into membraneless microdroplets upon aqueous rehydration. These microdroplets are proposed as protocells that can segregate and compartmentalize primitive molecules/reactions. Different primitive aqueous environments with a variety of salts could have hosted chemistries that formed polyester microdroplets. These salts could be essential cofactors of compartmentalized prebiotic reactions or even directly affect protocell structure. However, fully understanding polyester–salt interactions remains elusive, partially due to technical challenges of quantitative measurements in condensed phases. Here, spectroscopic and biophysical methods are applied to analyze salt uptake by polyester microdroplets. Inductively coupled plasma mass spectrometry is applied to measure the cation concentration within polyester microdroplets after addition of chloride salts. Combined with methods to determine the effects of salt uptake on droplet turbidity, size, surface potential and internal water distribution, it was observed that polyester microdroplets can selectively partition salt cations, leading to differential microdroplet coalescence due to ionic screening effects reducing electrostatic repulsion forces between microdroplets. Through applying existing techniques to novel analyses related to primitive compartment chemistry and biophysics, this study suggests that even minor differences in analyte uptake can lead to significant protocellular structural change.

DOI： 10.1002/smtd.202300119

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An investigation of the internal morphology of asbestos ferruginous bodies: constraining their role in the onset of malignant mesothelioma

Maya-Liliana Avramescu, Christian Potiszil, Tak Kunihiro, Kazunori Okabe, Eizo Nakamura

Particle and Fibre Toxicology 20 ( 1 ) 2023年5月

掲載種別：研究論文（学術雑誌）出版者・発行元：Springer Science and Business Media LLC

Abstract

Background

Asbestos is a fibrous mineral that was widely used in the past. However, asbestos inhalation is associated with an aggressive type of cancer known as malignant mesothelioma (MM). After inhalation, an iron-rich coat forms around the asbestos fibres, together the coat and fibre are termed an “asbestos ferruginous body” (AFB). AFBs are the main features associated with asbestos-induced MM. Whilst several studies have investigated the external morphology of AFBs, none have characterised the internal morphology. Here, cross-sections of multiple AFBs from two smokers and two non-smokers are compared to investigate the effects of smoking on the onset and growth of AFBs. Morphological and chemical observations of AFBs were undertaken by transmission electron microscopy, energy dispersive x-ray spectroscopy and selected area diffraction.

Results

The AFBs of all patients were composed of concentric layers of 2-line or 6-line ferrihydrite, with small spherical features being observed on the outside of the AFBs and within the cross-sections. The spherical components are of a similar size to Fe-rich inclusions found within macrophages from mice injected with asbestos fibres in a previous study. As such, the spherical components composing the AFBs may result from the deposition of Fe-rich inclusions during frustrated phagocytosis. The AFBs were also variable in terms of their Fe, P and Ca abundances, with some layers recording higher Fe concentrations (dense layers), whilst others lower Fe concentrations (porous layers). Furthermore, smokers were found to have smaller and overall denser AFBs than non-smokers.

Conclusions

The AFBs of smokers and non-smokers show differences in their morphology, indicating they grew in lung environments that experienced disparate conditions. Both the asbestos fibres of smokers and non-smokers were likely subjected to frustrated phagocytosis and accreted mucopolysaccharides, resulting in Fe accumulation and AFB formation. However, smokers’ AFBs experienced a more uniform Fe-supply within the lung environment compared to non-smokers, likely due to Fe complexation from cigarette smoke, yielding denser, smaller and more Fe-rich AFBs. Moreover, the lack of any non-ferrihydrite Fe phases in the AFBs may indicate that the ferritin shell was intact, and that ROS may not be the main driver for the onset of MM.

DOI： 10.1186/s12989-023-00522-0

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その他リンク： https://link.springer.com/article/10.1186/s12989-023-00522-0/fulltext.html

Insights into the formation and evolution of extraterrestrial amino acids from the asteroid Ryugu

Christian Potiszil, Tsutomu Ota, Masahiro Yamanaka, Chie Sakaguchi, Katsura Kobayashi, Ryoji Tanaka, Tak Kunihiro, Hiroshi Kitagawa, Masanao Abe, Akiko Miyazaki, Aiko Nakato, Satoru Nakazawa, Masahiro Nishimura, Tatsuaki Okada, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Yuichi Tsuda, Tomohiro Usui, Sei-ichiro Watanabe, Toru Yada, Kasumi Yogata, Makoto Yoshikawa, Eizo Nakamura

Nature Communications 14 ( 1 ) 2023年3月

掲載種別：研究論文（学術雑誌）出版者・発行元：Springer Science and Business Media LLC

Abstract

All life on Earth contains amino acids and carbonaceous chondrite meteorites have been suggested as their source at the origin of life on Earth. While many meteoritic amino acids are considered indigenous, deciphering the extent of terrestrial contamination remains an issue. The Ryugu asteroid fragments (JAXA Hayabusa2 mission), represent the most uncontaminated primitive extraterrestrial material available. Here, the concentrations of amino acids from two particles from different touchdown sites (TD1 and TD2) are reported. The concentrations show that N,N-dimethylglycine (DMG) is the most abundant amino acid in the TD1 particle, but below detection limit in the other. The TD1 particle mineral components indicate it experienced more aqueous alteration. Furthermore, the relationships between the amino acids and the geochemistry suggest that DMG formed on the Ryugu progenitor body during aqueous alteration. The findings highlight the importance of aqueous chemistry for defining the ultimate concentrations of amino acids in primitive extraterrestrial samples.

DOI： 10.1038/s41467-023-37107-6

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その他リンク： https://www.nature.com/articles/s41467-023-37107-6

Nitrogen Incorporation in Potassic and Micro- and Meso-Porous Minerals: Potential Biogeochemical Records and Targets for Mars Sampling

Matthew P. Nikitczuk, Gray E. Bebout, Charles A. Geiger, Tsutomu Ota, Takuya Kunihiro, John F. Mustard, Sæmundur A. Halldórsson, Eizo Nakamura

Astrobiology 2022年9月

On the origin and evolution of the asteroid Ryugu: A comprehensive geochemical perspective

Eizo NAKAMURA, Katsura KOBAYASHI, Ryoji TANAKA, Tak KUNIHIRO, Hiroshi KITAGAWA, Christian POTISZIL, Tsutomu OTA, Chie SAKAGUCHI, Masahiro YAMANAKA, Dilan M. RATNAYAKE, Havishk TRIPATHI, Rahul KUMAR, Maya-Liliana AVRAMESCU, Hidehisa TSUCHIDA, Yusuke YACHI, Hitoshi MIURA, Masanao ABE, Ryota FUKAI, Shizuho FURUYA, Kentaro HATAKEDA, Tasuku HAYASHI, Yuya HITOMI, Kazuya KUMAGAI, Akiko MIYAZAKI, Aiko NAKATO, Masahiro NISHIMURA, Tatsuaki OKADA, Hiromichi SOEJIMA, Seiji SUGITA, Ayako SUZUKI, Tomohiro USUI, Toru YADA, Daiki YAMAMOTO, Kasumi YOGATA, Miwa YOSHITAKE, Masahiko ARAKAWA, Atsushi FUJII, Masahiko HAYAKAWA, Naoyuki HIRATA, Naru HIRATA, Rie HONDA, Chikatoshi HONDA, Satoshi HOSODA, Yu-ichi IIJIMA, Hitoshi IKEDA, Masateru ISHIGURO, Yoshiaki ISHIHARA, Takahiro IWATA, Kosuke KAWAHARA, Shota KIKUCHI, Kohei KITAZATO, Koji MATSUMOTO, Moe MATSUOKA, Tatsuhiro MICHIKAMI, Yuya MIMASU, Akira MIURA, Tomokatsu MOROTA, Satoru NAKAZAWA, Noriyuki NAMIKI, Hirotomo NODA, Rina NOGUCHI, Naoko OGAWA, Kazunori OGAWA, Chisato OKAMOTO, Go ONO, Masanobu OZAKI, Takanao SAIKI, Naoya SAKATANI, Hirotaka SAWADA, Hiroki SENSHU, Yuri SHIMAKI, Kei SHIRAI, Yuto TAKEI, Hiroshi TAKEUCHI, Satoshi TANAKA, Eri TATSUMI, Fuyuto TERUI, Ryudo TSUKIZAKI, Koji WADA, Manabu YAMADA, Tetsuya YAMADA, Yukio YAMAMOTO, Hajime YANO, Yasuhiro YOKOTA, Keisuke YOSHIHARA, Makoto YOSHIKAWA, Kent YOSHIKAWA, Masaki FUJIMOTO, Sei-ichiro WATANABE, Yuichi TSUDA

Proceedings of the Japan Academy, Series B 98 ( 6 ) 227 - 282 2022年6月

Lithium in garnet as a tracer of subduction zone metamorphic reactions: The record in ultrahigh-pressure metapelites at Lago di Cignana, Italy

Gray E. Bebout, Tsutomu Ota, Takuya Kunihiro, William D. Carlson, Eizo Nakamura

Geosphere 18 ( 3 ) 1020 - 1029 2022年6月

掲載種別：研究論文（学術雑誌）出版者・発行元：Geological Society of America

Abstract

Lithium is of great interest as a tracer of metamorphic reactions and related fluid-mineral interactions because of its potential to isotopically fractionate during inter- and intracrystalline diffusional processes. Study of its transfer through subduction zones, based on study of arc volcanic and metamorphic rocks, can yield insight regarding ocean-to-mantle chemical cycling.

We investigated major- and trace-element concentrations and δ7Li in garnet in ultrahigh-pressure (UHP) Lago di Cignana metasedimentary rocks, relating these observations to reconstructed prograde devolatilization history. In all garnet crystals we studied, heavy rare earth elements (HREEs), Y, and Li showed strong zoning, with elevated concentrations in cores (15–50 ppm Li) and marked high-concentration anomalies (up to 117 ppm Li, 5500 ppm Y; little or no major-element shift) as growth annuli, in which some crystals showed subtle elevation in δ7Li greater than analytical error of ~3% (2σ). Rutile inclusions appeared abruptly at annuli and outward toward rims, accompanied by inclusions of a highly zoned, Ca- and rare earth element–rich phase and decreased Nb concentrations in garnet. These relationships are interpreted to reflect prograde garnet-forming reaction(s), in part involving titanite breakdown to stabilize rutile, which resulted in delivery of more abundant Y and HREEs at surfaces of growing garnet crystals to produce annuli. Co-enrichments in Li and Y + REEs are attributed to mutual incorporation via charge-coupled substitutions; thus, increased Li uptake was a passive consequence of elevated concentrations of Y + REEs. The small-scale fluctuations in δ7Li (overall range of ~9%) observed in some crystals may correlate with abrupt shifts in major- and trace-element concentrations, suggesting that changes in reactant phases exerted some control on the evolution of δ7Li. For one garnet crystal, late-stage growth following partial resorption produced deviation in major- and trace-element compositions, including Li concentration, accompanied by a 10%–15% negative shift in δ7Li, perhaps reflecting a change in the mechanism of incorporation or source of Li.

These results highlight the value of measuring the major- and trace-element and isotope compositions of garnets in high-pressure and UHP metamorphic rocks in which matrix mineral assemblages are extensively overprinted by recrystallization during exhumation histories. Lithium concentrations and isotope compositions of the garnets can add valuable information regarding prograde (and retrograde) reaction history, kinetics of porphyroblast growth, intracrystalline diffusion, and fluid-rock interactions. This work, integrated with previous study of devolatilization in the Schistes Lustrés/Cignana metasedimentary suite, indicates retention of a large fraction of the initially subducted sedimentary Li budget to depths approaching those beneath volcanic fronts, despite the redistribution of this Li among mineral phases during complex mineral reaction histories.

DOI： 10.1130/ges02473.1

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Magmatic-hydrothermal processes of the Laojunshan metamorphic massif in Southeastern Asia: Evidence from chemical and B-isotopic variations of deformed tourmalines

Wei Li, Shuyun Cao, Eizo Nakamura, Tsutomu Ota, Zhong Liu, Yanlong Dong, Tak Kunihiro

Lithos 412-413 106609 - 106609 2022年3月

The Asteroid 162173 Ryugu: a Cometary Origin

Hitoshi Miura, Eizo Nakamura, Tak Kunihiro

The Astrophysical Journal Letters 925 ( 2 ) L15 - L15 2022年2月

掲載種別：研究論文（学術雑誌）出版者・発行元：American Astronomical Society

Abstract

The Japanese Hayabusa2 mission has revealed in detail the physical characteristics of the C-type asteroid 162173 Ryugu, in particular, its spinning top-shaped rubble-pile structure and potentially high organic content. A widely accepted formation scenario for Ryugu is catastrophic collision between larger asteroids and the subsequent slow gravitational accumulation of collisional debris. An alternative scenario is that Ryugu is an extinct comet that lost its icy components. Here, we numerically simulated the sublimation of water ice from a porous cometary nucleus until the refractory components, such as silicate rocks and organic matter, were left behind as evaporative residues. Such a process represents the transformation from a comet to an asteroid. The spin-up related to the shrinking nucleus, associated with water ice sublimation, was also calculated. The result of the calculation indicates that the cometary origin scenario can account for all the features of Ryugu discussed above. We conclude that organic-rich spinning top-shaped rubble-pile asteroids, such as Ryugu, are comet–asteroid transition objects or extinct comets.

DOI： 10.3847/2041-8213/ac4bd5

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その他リンク： https://iopscience.iop.org/article/10.3847/2041-8213/ac4bd5/pdf

Nitrogenous Altered Volcanic Glasses as Targets for Mars Sample Return: Examples From Antarctica and Iceland

M. P. Nikitczuk, G. E. Bebout, T. Ota, T. Kunihiro, J. F. Mustard, R. L. Flemming, R. Tanaka, S. A. Halldórsson, E. Nakamura

Journal of Geophysical Research: Planets 127 ( 2 ) 2022年2月

The trace element composition of chondrule constituents: Implications for sample return methodologies and the chondrule silicate reservoir

Tak Kunihiro, Tsutomu Ota, Masahiro Yamanaka, Christian Potiszil, Eizo Nakamura

METEORITICS & PLANETARY SCIENCE 2021年6月

The Albedo of Ryugu: Evidence for a High Organic Abundance, as Inferred from the Hayabusa2 Touchdown Maneuver

Christian Potiszil, Ryoji Tanaka, Katsura Kobayashi, Tak Kunihiro, Eizo Nakamura

ASTROBIOLOGY 20 ( 7 ) 916 - 921 2020年6月

Concentration of meteoritic free organic matter by fluid transport and adsorption

C. Potiszil, R. Tanaka, T. Ota, T. Kunihiro, K. Kobayashi, E. Nakamura

Geochemical Perspectives Letters 13 30 - 35 2020年3月

Lithium- and oxygen-isotope compositions of chondrule constituents in the Allende meteorite

Tak Kunihiro, Tsutomu Ota, Eizo Nakamura

GEOCHIMICA ET COSMOCHIMICA ACTA 252 107 - 125 2019年5月

Hypervelocity collision and water-rock interaction in space preserved in the Chelyabinsk ordinary chondrite

Eizo Nakamura, Tak Kunihiro, Tsutomu Ota, Chie Sakaguchi, Ryoji Tanaka, Hiroshi Kitagawa, Katsura Kobayashi, Masahiro Yamanaka, Yuri Shimaki, Gray E. Bebout, Hitoshi Miura, Tetsuo Yamamoto, Vladimir Malkovets, Victor Grokhovsky, Olga Koroleva, Konstantin Litasov

PROCEEDINGS OF THE JAPAN ACADEMY SERIES B-PHYSICAL AND BIOLOGICAL SCIENCES 95 ( 4 ) 165 - 177 2019年4月

Determination of Abundances of Fifty-Two Elements in Natural Waters by ICP-MS with Freeze-Drying Pre-concentration

Que D. Hoang, Tak Kunihiro, Chie Sakaguchi, Masahiro Yamanaka, Hiroshi Kitagawa, Eizo Nakamura

GEOSTANDARDS AND GEOANALYTICAL RESEARCH 43 ( 1 ) 147 - 161 2019年3月

Oxygen isotopes of chondritic components

Hisayoshi Yurimoto, Alexander N. Krot, Byeon Gak Choi, Jerome Aleon, Takuya Kunihiro, Adrian J. Brearley

Oxygen in the Solar System 68 141 - 186 2018年11月

Software Dedicated for the Curation of Geochemical Data Sets in Analytical Laboratories

Yusuke Yachi, Hiroshi Kitagawa, Tak Kunihiro, Eizo Nakamura

GEOSTANDARDS AND GEOANALYTICAL RESEARCH 38 ( 1 ) 95 - 102 2014年3月

Space environment of an asteroid preserved on micrograins returned by the Hayabusa spacecraft

Eizo Nakamura, Akio Makishima, Takuya Moriguti, Katsura Kobayashi, Ryoji Tanaka, Tak Kunihiro, Tatsuki Tsujimori, Chie Sakaguchi, Hiroshi Kitagawa, Tsutomu Ota, Yusuke Yachi, Toru Yada, Masanao Abe, Akio Fujimura, Munetaka Ueno, Toshifumi Mukai, Makoto Yoshikawa, Jun'ichiro Kawaguchi

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 109 ( 11 ) E624 - E629 2012年3月

「はやぶさ」回収試料の初期分析に至るまで：地球惑星物質総合解析システムの構築招待査読

中村栄三, 牧嶋昭夫, 森口拓弥, 小林桂, 田中亮吏, 国広卓也, 辻森樹

表面科学 33 ( 12 ) 681 - 686 2012年

In situ ion-microprobe determination of trace element partition coefficients for hornblende, plagioclase, orthopyroxene, and apatite in equilibrium with natural rhyolitic glass, Little Glass Mountain Rhyofite, California 査読

Brophy J.G., Ota T., Kunihiro T., Tsujimori T., Nakamura E.

96 ( 11-12 ) 1838 - 1850 2011年11月

Melt inclusion Pb-isotope analysis by LA-MC-ICPMS: Assessment of analytical performance and application to OIB genesis

Bence Paul, Jon D. Woodhead, Janet Hergt, Leonid Danyushevsky, Takuya Kunihiro, Eizo Nakamura

Chemical Geology 289 ( 3-4 ) 210 - 223 2011年10月

Sr-Nd-Hf-Pb isotopic characteristics of North-Western and Southern Ethiopian lithospheric mantle 査読

Melesse A, Kunihiro T, Ota T, Tanaka R, Moriguti T, Nakamura E

Geochimica Et Cosmochimica Acta 74 ( 12 ) A697 2010年

Elemental and isotopic abundances of lithium in chondrule constituents in the Allende meteorite

Seiji Maruyama, Masaki Watanabe, Tak Kunihiro, Eizo Nakamura

GEOCHIMICA ET COSMOCHIMICA ACTA 73 ( 3 ) 778 - 793 2009年2月

MegaSIMS: a SIMS/AMS hybrid for measurement of the Sun's oxygen isotopic composition

Peter H. Mao, Donald S. Burnett, Christopher D. Coath, George Jarzebinski, Takuya Kunihiro, Kevin D. McKeegan

Applied Surface Science 255 ( 4 ) 1461 - 1464 2008年12月

Boron cycling by subducted lithosphere; insights from diamondiferous tourmaline from the Kokchetav ultrahigh-pressure metamorphic belt

Tsutomu Ota, Katsura Kobayashi, Takuya Kunihiro, Eizo Nakamura

Geochimica et Cosmochimica Acta 72 ( 14 ) 3531 - 3541 2008年7月

Oxygen-isotopic compositions of low-FeO relicts in high-FeO host chondrules in Acfer 094, a type 3.0 carbonaceous chondrite closely related to CM

Tak Kunihiro, Alan E. Rubin, John T. Wasson

Geochimica et Cosmochimica Acta 69 ( 15 ) 3831 - 3840 2005年8月

Carbon-rich chondritic clast PV1 from the Plainview H-chondrite regolith breccia: Formation from H3 chondrite material by possible cometary impact

Alan E. Rubin, Josep M. Trigo-Rodriguez, Takuya Kunihiro, Gregory W. Kallemeyn, John T. Wasson

Geochimica et Cosmochimica Acta 69 ( 13 ) 3419 - 3430 2005年7月

Microscopic oxygen isotopic homogeneity/heterogeneity in the matrix of the Vigarano CV3 chondrite

Takuya Kunihiro, Kazuhide Nagashima, Hisayoshi Yurimoto

Geochimica et Cosmochimica Acta 69 ( 3 ) 763 - 773 2005年2月

Oxygen-isotopic compositions of relict and host grains in chondrules in the Yamato 81020 CO3.0 chondrite

Takuya Kunihiro, Alan E. Rubin, Kevin D. McKeegan, John T. Wasson

Geochimica et Cosmochimica Acta 68 ( 17 ) 3599 - 3606 2004年9月

Initial ²⁶Al/²⁷Al in carbonaceous-chondrite chondrules: Too little ²⁶Al to melt asteroids

Takuya Kunihiro, Alan E. Rubin, Kevin D. McKeegan, John T. Wasson

Geochimica et Cosmochimica Acta 68 ( 13 ) 2947 - 2957 2004年7月

High precision isotope micro-imaging of materials 査読

Hisayoshi Yurimoto, Kazuhide Nagashima, Takuya Kunihiro

Applied Surface Science 203-204 793 - 797 2003年1月

Noise characteristics of stacked CMOS active pixel sensor for charged particles 査読

Takuya Kunihiro, Kazuhide Nagashima, Isao Takayanagi, Junichi Nakamura, Koji Kosaka, Hisayoshi Yurimoto

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 470 ( 3 ) 512 - 519 2001年9月

Output characteristics of stacked CMOS-type active pixel sensor for charged particles 査読

Kazuhide Nagashima, Takuya Kunihiro, Isao Takayanagi, Junichi Nakamura, Koji Kosaka, Hisayoshi Yurimoto

Surface and Interface Analysis 31 ( 2 ) 131 - 137 2001年2月

A low dark current stacked CMOS-APS for charged particle imaging 査読

Isao Takayanagi, Junichi Nakamura, El Sayed Eid, Eric R. Fossum, Kazuhide Nagashima, Takuya Kunihiro, Hisayoshi Yurimoto

Technical Digest-International Electron Devices Meeting 551 - 554 2001年

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