Updated on 2025/03/27

写真a

 
SETO YUSUKE
 
Organization
Graduate School of Science Department of Geosciences Associate Professor
School of Science Department of Geosciences
Title
Associate Professor
Affiliation
Institute of Science
Affiliation campus
Sugimoto Campus

Position

  • Graduate School of Science Department of Geosciences 

    Associate Professor  2022.04 - Now

  • School of Science Department of Geosciences 

    Associate Professor  2022.04 - Now

Degree

  • 博士(理学) （ Kyoto University ）

Research Areas

  • Natural Science / Space and planetary sciences

  • Natural Science / Solid earth sciences

Research Interests

  • 鉱物

  • Crystal

  • Electron microscopy

  • X-ray diffraction

  • Meteorite

Professional Memberships

  • 日本高圧力学会

    2005.09 - Now

  • 日本鉱物科学会

    2000.08 - Now

  • 日本地球惑星科学連合

    2000.04 - Now

Committee Memberships (off-campus)

  • 論文賞選考委員   日本鉱物科学会  

    2024.08 - Now 

  • 理事   日本鉱物科学会  

    2024.08 - Now 

  • 行事幹事   日本鉱物科学会  

    2024.08 - Now 

  • Elements幹事   日本鉱物科学会  

    2022.08 - 2024.07 

  • 庶務幹事   日本高圧力学会  

    2021.09 - 2023.08 

  • 行事委員   日本鉱物科学会  

    2021.08 - Now 

  • 会計幹事   日本高圧力学会  

    2014.09 - 2016.08 

▼display all

Awards

  • 奨励賞

    2015.09   日本鉱物科学会  

  • 奨励賞

    2011.11   日本高圧力学会  

  • 論文賞

    2008.09   日本鉱物科学会  

Job Career (off-campus)

  • Osaka Metropolitan University   Graduate School of Science, Department of Geosciences

    2022.04 - Now

  • Kobe University   Graduate School of Science

    2014.08 - 2022.03

Papers

  • Direct measurement of lattice behavior during femtosecond laser-driven shock front formation in copper

    Naoya Egashira, Tomoki Matsuda, Takuo Okuchi, Yusuke Seto, Yusuke Ito, Takahisa Shobu, Nobuhiko Nakanii, Yuichi Inubushi, Tadashi Togashi, Kohei Miyanishi, Tsutomu Mashimo, Tomokazu Sano

    Journal of Applied Physics   137 ( 10 )   2025.03（ ISSN:0021-8979 ） （ eISSN:1089-7550 ）

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    Publishing type：Research paper (scientific journal)  

    Femtosecond laser-driven shock waves exhibit characteristic features that form distinctive microstructures not formed by plate impacts or nanosecond laser-driven shock waves. A key to understanding this phenomenon is understanding the lattice behavior inside the shock front, which is the boundary between the ambient and shock compression states. However, direct measurements of the lattice spacing inside a femtosecond laser-driven shock front have not yet been performed. Here, we report in situ measurements of lattice spacing using x-ray free electron laser diffraction with a pulse width of <10 fs during the shock rise in single-crystal copper irradiated directly in air with a femtosecond laser pulse on the order of 1014 W/cm2 at a pulse width of 101 fs. The lattice spacing of the femtosecond laser-irradiated single-crystal Cu (002) plane starts to compress 6.3 ps after femtosecond laser irradiation. It takes 15.7 ps for the plane to reach peak compression, at which point the compressive elastic strain is 24.3%. Therefore, the shock front was found to form at an elastic compressive strain rate of 1.55 × 1010/s in this shock-driving situation. It is suggested that the initiation of plasticity under such ultrafast deformation at the most elastic compression is based on both dislocation multiplication and dislocation generation mechanisms.

    DOI： 10.1063/5.0253150

  • Microscopic slickenside as a record of weak shock metamorphism in the surface layer of asteroid Ryugu

    Masaaki Miyahara, Takaaki Noguchi, Toru Matsumoto, Naotaka Tomioka, Akira Miyake, Yohei Igami, Yusuke Seto, Mitsutaka Haruta, Hikaru Saito, Satoshi Hata, Hope A. Ishii, John P. Bradley, Kenta K. Ohtaki, Elena Dobrică, Hugues Leroux, Corentin Le Guillou, Damien Jacob, Francisco de la Peña, Sylvain Laforet, Bahae‐Eddine Mouloud, Maya Marinova, Falko Langenhorst, Dennis Harries, Pierre Beck, Thi H. V. Phan, Rolando Rebois, Neyda M. Abreu, Jennifer Gray, Thomas Zega, Pierre‐M. Zanetta, Michelle S. Thompson, Rhonda Stroud, Kate Burgess, Brittany A. Cymes, John C. Bridges, Leon Hicks, Martin R. Lee, Luke Daly, Phil A. Bland, Michael E. Zolensky, David R. Frank, James Martinez, Akira Tsuchiyama, Masahiro Yasutake, Junya Matsuno, Shota Okumura, Itaru Mitsukawa, Kentaro Uesugi, Masayuki Uesugi, Akihisa Takeuchi, Mingqi Sun, Satomi Enju, Aki Takigawa, Tatsuhiro Michikami, Tomoki Nakamura, Megumi Matsumoto, Yusuke Nakauchi, Masanao Abe, Satoru Nakazawa, Tatsuaki Okada, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Makoto Yoshikawa, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Tomohiro Usui, Toru Yada, Hisayoshi Yurimoto, Kazuhide Nagashima, Noriyuki Kawasaki, Naoya Sakamotoa, Ryuji Okazaki, Hikaru Yabuta, Hiroshi Naraoka, Kanako Sakamoto, Shogo Tachibana, Sei‐ichiro Watanabe, Yuichi Tsuda

    Meteoritics & Planetary Science   59 ( 12 )   3181 - 3192   2024.12（ ISSN:10869379 ） （ eISSN:1945-5100 ）

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    Publishing type：Research paper (scientific journal)  

    Abstract

    The surface morphology of regolith grains from the C‐type asteroid Ryugu was studied in search of evidence of impact events on the asteroid. Scanning electron microscopy revealed that ~8% of C0105‐042 Ryugu grains have a smooth surface on one side of the grains. One of these grains has striated linear grooves (striations) on its smooth surface. Transmission electron microscopy of the grain showed that a porous fine‐grained Mg‐Fe phyllosilicate assemblage, which is the main component of Ryugu grains, is compacted near the smooth surface. The smooth surface with striations closely resembles a slickenside, a characteristic texture found in terrestrial fault rocks formed by shear deformation. There is no evidence of melting/decomposition in the Mg‐Fe phyllosilicates near the smooth surface, indicating that the shear heating temperature is less than ~1100 K. Assuming that the average length of the striations corresponds to the minimum displacement of the micro‐fault, the shock pressure recorded in the C0105‐042 Ryugu grain is estimated to be &lt;~4.5 GPa by a fault mechanics calculation. The shock pressures of C0105‐042, together with those of C0014 (~2 GPa) and C0055 (&gt;~3.9 GPa) in previous studies suggest that the impact velocities recorded in these grains are &lt; ~0.89–1.63 km s<sup>−1</sup>. Based on the impact velocities, these grains may record an impact event that occurred when asteroid Ryugu was in the orbit in Main Belt.

    DOI： 10.1111/maps.14271

  • Progressive change in dislocation microstructures in shocked calcite with pressure: Characterization of micrometeoroid bombardment on asteroid Ryugu

    Naotaka Tomioka, Kosuke Kurosawa, Akira Miyake, Yohei Igami, Takayoshi Nagaya, Takaaki Noguchi, Toru Matsumoto, Masaaki Miyahara, Yusuke Seto

    American Mineralogist   2024.09（ ISSN:0003-004X ） （ eISSN:1945-3027 ）

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    Publishing type：Research paper (scientific journal)  

    Abstract

    Shock recovery experiments were performed using a two-stage light gas gun to clarify the progressive deformation microstructures of calcite at the submicron scale concerning pressure. Decaying compression pulses were produced using a projectile that was smaller than the natural marble target. In two experiments, natural marble samples were shocked to 13 and 18 GPa at the epicenters of the targets. Calcite grains shocked in the pressure range of 1.1–18 GPa were examined using polarized light microscopy and (scanning) transmission electron microscopy. The density of free dislocations in the grains shocked at 1.1–2.2 GPa [108–9 (cm-2)] is comparable to that of unshocked Carrara calcite grains. Subparallel bands of entangled dislocations less than 1 µm are formed at 4.2 GPa, and strongly entangled dislocations spread throughout the focused ion beam (FIB) sections at 7.3–18 GPa pressures. Dislocations selectively nucleate and entangle near the slip planes at pressures above ~3 GPa, corresponding to the transition from sharp extinction to undulatory extinction, according to the microstructural evolution with shock pressure. Above approximately 6 GPa, the dislocations nucleated homogeneously throughout the calcite crystals. The dislocation microstructure in a calcite grain collected from the asteroid Ryugu particle is similar to that of the experimentally shocked calcite at 4.2 GPa. The estimated pressure of 2–3 GPa, determined through fault mechanics analyses and the presence of dense sulfide minerals in the Ryugu particles, is in line with this pressure.

    DOI： 10.2138/am-2024-9540

  • Electron microscopy observations of the diversity of Ryugu organic matter and its relationship to minerals at the micro- to nano-scale

    Rhonda M. Stroud, Jens Barosch, Lydie Bonal, Katherine Burgess, George D. Cody, Bradley T. De Gregorio, Luke Daly, Emmanuel Dartois, Elena Dobrică, Jean Duprat, Cecile Engrand, Dennis Harries, Minako Hashiguchi, Hope Ishii, Yoko Kebukawa, A. David Kilcoyne, Falko Langenhorst, Martin R. Lee, Larry R. Nittler, Eric Quirico, Taiga Okumura, Laurent Remusat, Scott Sandford, Hikaru Yabuta, Masanao Abe, Neyda M. Abreu, Paul A.J. Bagot, Pierre Beck, Laure Bejach, Phil A. Bland, John C. Bridges, Brittany A. Cymes, Alexandre Dazzi, Francisco de la Peña, Ariane Deniset-Besseau, Satomi Enju, Yuma Enokido, David R. Frank, Jennifer Gray, Mitsutaka Haruta, Satoshi Hata, Leon Hicks, Yohei Igami, Damien Jacob, Kanami Kamide, Mutsumi Komatsu, Sylvain Laforet, Hugues Leroux, Corentin Le Guillou, Zita Martins, Maya Marinova, James Martinez, Jérémie Mathurin, Megumi Matsumoto, Toru Matsumoto, Junya Matsuno, Samuel McFadzean, Tatsuhiro Michikami, Itaru Mitsukawa, Akira Miyake, Masaaki Miyahara, Akiko Miyazaki, Gilles Montagnac, Smail Mostefaoui, Tomoki Nakamura, Aiko Nakato, Hiroshi Naraoka, Yusuke Nakauchi, Satoru Nakazawa, Masahiro Nishimura, Takaaki Noguchi, Kenta Ohtaki, Takuji Ohigashi, Tatsuaki Okada, Shota Okumura, Ryuji Okazaki, Thi H.V. Phan, Rolando Rebois, Kanako Sakamoto, Takanao Saiki, Hikaru Saito, Yusuke Seto, Miho Shigenaka, William Smith, Hiroki Suga, Mingqi Sun, Shogo Tachibana, Yoshio Takahashi, Yasuo Takeichi, Akihisa Takeuchi, Aki Takigawa, Yusuke Tamenori, Satoshi Tanaka, Fuyuto Terui, Michelle S. Thompson, Naotaka Tomioka, Akira Tsuchiyama, Yuichi Tsuda, Kentaro Uesugi, Masayuki Uesugi

    Meteoritics and Planetary Science   59 ( 8 )   2023 - 2043   2024.08（ ISSN:1086-9379 ）

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    Publishing type：Research paper (scientific journal)  

    Transmission electron microscopy analyses of Hayabusa2 samples show that Ryugu organic matter exhibits a range of morphologies, elemental compositions, and carbon functional chemistries consistent with those of carbonaceous chondrites that have experienced low-temperature aqueous alteration. Both nanoglobules and diffuse organic matter are abundant. Non-globular organic particles are also present, and including some that contain nanodiamond clusters. Diffuse organic matter is finely distributed in and around phyllosilicates, forms coatings on other minerals, and is also preserved in vesicles in secondary minerals such as carbonate and pyrrhotite. The average elemental compositions determined by energy-dispersive spectroscopy of extracted, demineralized insoluble organic matter samples A0107 and C0106 are C100N3O9S1 and C100N3O7S1, respectively, with the difference in O/C slightly outside the difference in the standard error of the mean. The functional chemistry of the nanoglobules varies from mostly aromatic C=C to mixtures of aromatic C=C, ketone C=O, aliphatic (CHn), and carboxyl (COOH) groups. Diffuse organic matter associated with phyllosilicates has variable aromatic C, ketone and carboxyl groups, and some localized aliphatics, but is dominated by molecular carbonate (CO3) absorption, comparable to prior observations of clay-bound organic matter in CI meteorites.

    DOI： 10.1111/maps.14128

  • Incipient space weathering on asteroid 162173 Ryugu recorded by pyrrhotite

    Dennis Harries, Toru Matsumoto, Falko Langenhorst, Takaaki Noguchi, Akira Miyake, Yohei Igami, Mitsutaka Haruta, Yusuke Seto, Masaaki Miyahara, Naotaka Tomioka, Hikaru Saito, Satoshi Hata, Aki Takigawa, Yusuke Nakauchi, Shogo Tachibana, Tomoki Nakamura, Megumi Matsumoto, Hope A. Ishii, John P. Bradley, Kenta Ohtaki, Elena Dobrică, Hugues Leroux, Corentin Le Guillou, Damien Jacob, Francisco de la Peña, Sylvain Laforet, Bahae eddine Mouloud, Maya Marinova, Pierre Beck, Van T.H. Phan, Rolando Rebois, Neyda M. Abreu, Jennifer Gray, Thomas Zega, Pierre M. Zanetta, Michelle S. Thompson, Rhonda Stroud, Kate Burgess, Brittany A. Cymes, John C. Bridges, Leon Hicks, Martin R. Lee, Luke Daly, Phil A. Bland, Michael E. Zolensky, David R. Frank, James Martinez, Akira Tsuchiyama, Masahiro Yasutake, Junya Matsuno, Shota Okumura, Itaru Mitsukawa, Kentaro Uesugi, Masayuki Uesugi, Akihisa Takeuchi, Mingqi Sun, Satomi Enju, Tatsuhiro Michikami, Hisayoshi Yurimoto, Ryuji Okazaki, Hikaru Yabuta, Hiroshi Naraoka, Kanako Sakamoto, Toru Yada, Masahiro Nishimura, Aiko Nakato, Akiko Miyazaki, Kasumi Yogata, Masanao Abe, Tatsuaki Okada, Tomohiro Usui, Makoto Yoshikawa, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Satoru Nakazawa, Sei ichiro Watanabe, Yuichi Tsuda

    Meteoritics and Planetary Science   59 ( 8 )   2134 - 2148   2024.08（ ISSN:10869379 ）

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    Publishing type：Research paper (scientific journal)  

    Regolith samples returned from asteroid 162173 Ryugu by the Hayabusa2 mission provide direct means to study how space weathering operates on the surfaces of hydrous asteroids. The mechanisms of space weathering, its effects on mineral surfaces, and the characteristic time scales on which alteration occurs are central to understanding the spectroscopic properties and the taxonomy of asteroids in the solar system. Here, we investigate the behavior of the iron monosulfides mineral pyrrhotite (Fe1−xS) at the earliest stages of space weathering. Using electron microscopy methods, we identified a partially exposed pyrrhotite crystal that morphologically shows evidence for mass loss due to exposure to solar wind ion irradiation. We find that crystallographic changes to the pyrrhotite can be related to sulfur loss from its space-exposed surface and the diffusive redistribution of resulting excess iron into the interior of the crystal. Diffusion profiles allow us to estimate an order of magnitude of the exposure time of a few thousand years consistent with previous estimates of space exposure. During this interval, the adjacent phyllosilicates did not acquire discernable damage, suggesting that they are less susceptible to alteration by ion irradiation than pyrrhotite.

    DOI： 10.1111/maps.14176

  • Transient Creep in Olivine at Shallow Mantle Pressures: Implications for Time‐Dependent Rheology in Post‐Seismic Deformation

    Tomohiro Ohuchi, Yuji Higo, Noriyoshi Tsujino, Yusuke Seto, Sho Kakizawa, Yoshinori Tange, Yamato Miyagawa, Yoshio Kono, Hirokatsu Yumoto, Takahisa Koyama, Hiroshi Yamazaki, Yasunori Senba, Haruhiko Ohashi, Ichiro Inoue, Yujiro Hayashi, Makina Yabashi, Tetsuo Irifune

    Geophysical Research Letters   51 ( 11 )   2024.06（ ISSN:00948276 ） （ eISSN:1944-8007 ）

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    Publishing type：Research paper (scientific journal)  

    Abstract

    Transient creep in olivine aggregates has been studied by stress‐relaxation experiments at pressures of 1.7–3.6 GPa and at temperatures of ≤1020 K in a DIA apparatus. Time‐dependent deformation of olivine at small strains (&lt;0.07) was monitored with an ∼1 s of time resolution using a combination of a high‐flux synchrotron X‐ray and a cadmium telluride imaging detector. The observed deformation was found to follow the Burgers creep function with the transient relaxation time ranging from 50 (±20) to 1,880 (±750) s. We show that the Burgers creep for olivine cannot account for the low viscosities in early post‐seismic deformation reported by geodetic observations (&lt;7 × 10<sup>17</sup> Pa·s). In contrast, the time‐dependent increase in viscosity observed in late post‐seismic deformation (10<sup>18</sup>−10<sup>20</sup> Pa·s) is explained by the Burgers rheology, suggesting that the combination of the Burgers model and another model is needed for the interpretation of post‐seismic deformation.

    DOI： 10.1029/2024GL108356

  • Observation of high-pressure polymorphs in bulk silicon formed at relativistic laser intensities

    Rapp L.

    Physical Review Research   6 ( 2 )   2024.04（ ISSN:26431564 ）

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  • Influx of nitrogen-rich material from the outer Solar System indicated by iron nitride in Ryugu samples

    Matsumoto Toru, Noguchi Takaaki, Miyake Akira, Igami Yohei, Haruta Mitsutaka, Seto Yusuke, Miyahara Masaaki, Tomioka Naotaka, Saito Hikaru, Hata Satoshi, Harries Dennis, Takigawa Aki, Nakauchi Yusuke, Tachibana Shogo, Nakamura Tomoki, Matsumoto Megumi, Ishii Hope A., Bradley John P., Ohtaki Kenta, Dobrică Elena, Leroux Hugues, Le Guillou Corentin, Jacob Damien, de la Peña Francisco, Laforet Sylvain, Marinova Maya, Langenhorst Falko, Beck Pierre, Phan Thi H. V., Rebois Rolando, Abreu Neyda M., Gray Jennifer, Zega Thomas, Zanetta Pierre-M., Thompson Michelle S., Stroud Rhonda, Burgess Kate, Cymes Brittany A., Bridges John C., Hicks Leon, Lee Martin R., Daly Luke, Bland Phil A., Zolensky Michael E., Frank David R., Martinez James, Tsuchiyama Akira, Yasutake Masahiro, Matsuno Junya, Okumura Shota, Mitsukawa Itaru, Uesugi Kentaro, Uesugi Masayuki, Takeuchi Akihisa, Sun Mingqi, Enju Satomi, Michikami Tatsuhiro, Yurimoto Hisayoshi, Okazaki Ryuji, Yabuta Hikaru, Naraoka Hiroshi, Sakamoto Kanako, Yada Toru, Nishimura Masahiro, Nakato Aiko, Miyazaki Akiko, Yogata Kasumi, Abe Masanao, Okada Tatsuaki, Usui Tomohiro, Yoshikawa Makoto, Saiki Takanao, Tanaka Satoshi, Terui Fuyuto, Nakazawa Satoru, Watanabe Sei-ichiro, Tsuda Yuichi

    Nature Astronomy   8 ( 2 )   207 - 215   2024.02（ eISSN:23973366 ）

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    Large amounts of nitrogen compounds, such as ammonium salts, may be stored in icy bodies and comets, but the transport of these nitrogen-bearing solids into the near-Earth region is not well understood. Here, we report the discovery of iron nitride on magnetite grains from the surface of the near-Earth C-type carbonaceous asteroid Ryugu, suggesting inorganic nitrogen fixation. Micrometeoroid impacts and solar wind irradiation may have caused the selective loss of volatile species from major iron-bearing minerals to form the metallic iron. Iron nitride is a product of nitridation of the iron metal by impacts of micrometeoroids that have higher nitrogen contents than the CI chondrites. The impactors are probably primitive materials with origins in the nitrogen-rich reservoirs in the outer Solar System. Our observation implies that the amount of nitrogen available for planetary formation and prebiotic reactions in the inner Solar System is greater than previously recognized.

  • In situ investigation of an organic micro‐globule and its mineralogical context within a Ryugu “sand” grain

    Van T. H. Phan, Pierre Beck, Rolando Rebois, Eric Quirico, Takaaki Noguchi, Toru Matsumoto, Akira Miyake, Yohei Igami, Mitsutaka Haruta, Hikaru Saito, Satoshi Hata, Yusuke Seto, Masaaki Miyahara, Naotaka Tomioka, Hope A. Ishii, John P. Bradley, Kenta K. Ohtaki, Elena Dobrică, Hugues Leroux, Corentin Le Guillou, Damien Jacob, Francisco de la Peña, Sylvain Laforet, Maya Marinova, Falko Langenhorst, Dennis Harries, Neyda M. Abreu, Jennifer Gray, Thomas Zega, Pierre‐M. Zanetta, Michelle S. Thompson, Rhonda Stroud, Jérémie Mathurin, Alexandre Dazzi, Emmanuel Dartois, Cécile Engrand, Kate Burgess, Brittany A. Cymes, John C. Bridges, Leon Hicks, Martin R. Lee, Luke Daly, Phil A. Bland, Michael E. Zolensky, David R. Frank, James Martinez, Akira Tsuchiyama, Masahiro Yasutake, Junya Matsuno, Shota Okumura, Itaru Mitsukawa, Kentaro Uesugi, Masayuki Uesugi, Akihisa Takeuchi, Mingqi Sun, Satomi Enju, Aki Takigawa, Tatsuhiro Michikami, Tomoki Nakamura, Megumi Matsumoto, Yusuke Nakauchi, Masanao Abe, Satoru Nakazawa, Tatsuaki Okada, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Makoto Yoshikawa, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Tomohiro Usui, Toru Yada, Hisayoshi Yurimoto, Kazuhide Nagashima, Noriyuki Kawasaki, Naoya Sakamotoa, Peter Hoppe, Ryuji Okazaki, Hikaru Yabuta, Hiroshi Naraoka, Kanako Sakamoto, Shogo Tachibana, Sei‐ichiro Watanabe, Yuichi Tsuda

    Meteoritics &amp; Planetary Science   59 ( 8 )   1983 - 2001   2024.01（ ISSN:1086-9379 ） （ eISSN:1945-5100 ）

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    Publishing type：Research paper (scientific journal)  

    Abstract

    The Hayabusa2 mission from the Japan Aerospace Exploration Agency (JAXA) returned to the Earth samples of carbonaceous asteroid (162173) Ryugu. This mission offers a unique opportunity to investigate in the laboratory samples from a C‐type asteroid, without physical or chemical alteration by the terrestrial atmosphere. Here, we report on an investigation of the mineralogy and the organo‐chemistry of Hayabusa2 samples using a combination of micro‐ and nano‐infrared spectroscopy. Particles investigated with conventional FTIR spectroscopy have spectra dominated by phyllosilicate‐related absorption, as observed for samples of CI‐chondrites, selected ungrouped carbonaceous chondrites, and selected hydrated micrometeorites. Ryugu samples show smaller sulfate‐related absorption than CI‐chondrites. Our samples that were only briefly exposed to the Earth atmosphere show absorptions related to molecular water, revealing fast terrestrial contamination of the spectral signature at 3 μm. Overall, our FTIR data are in agreement with other work done on Ryugu samples, revealing a low degree of mineralogical variability across Ryugu samples. AFM‐IR mapping of the grains shows the presence of a micrometer‐sized organic globule in one of our analyzed grains. The AFM‐IR spectra obtained on this globule are similar to IR spectra obtained on IOM suggesting that it is constituted of refractory organic matter. This globule may host silicate in its interior, with a different mineralogy than bulk Ryugu phyllosilicate. The shape, presence of peculiar silicate, and the nature of organic constituting the globule point toward a pre‐accretionary origin of this globule and that at least part of Ryugu organics were inherited from the protosolar nebulae or the interstellar media. Altogether, our results show the similarities between Ryugu samples and CI chondrites.

    DOI： 10.1111/maps.14122

  • Four‐dimensional‐STEM analysis of the phyllosilicate‐rich matrix of Ryugu samples

    Bahae‐eddine Mouloud, Damien Jacob, Francisco de la Peña, Maya Marinova, Corentin Le Guillou, Jean‐Christophe Viennet, Sylvain Laforet, Hugues Leroux, Adrien Teurtrie, Takaaki Noguchi, Toru Matsumoto, Akira Miyake, Yohei Igami, Mitsutaka Haruta, Hikaru Saito, Satoshi Hata, Yusuke Seto, Masaaki Miyahara, Naotaka Tomioka, Hope A. Ishii, John P. Bradley, Kenta K. Ohtaki, Elena Dobrica, Falko Langenhorst, Dennis Harries, Pierre Beck, Thi H. V. Phan, Rolando Rebois, Neyda M. Abreu, Jennifer Gray, Thomas Zega, Pierre‐M. Zanetta, Michelle S. Thompson, Rhonda Stroud, Kate Burgess, Brittany A. Cymes, John C. Bridges, Leon Hicks, Martin R. Lee, Luke Daly, Phil A. Bland, Michael E. Zolensky, David R. Frank, James Martinez, Akira Tsuchiyama, Masahiro Yasutake, Junya Matsuno, Shota Okumura, Itaru Mitsukawa, Kentaro Uesugi, Masayuki Uesugi, Akihisa Takeuchi, Mingqi Sun, Satomi Enju, Aki Takigawa, Tatsuhiro Michikami, Tomoki Nakamura, Megumi Matsumoto, Yusuke Nakauchi, Masanao Abe, Satoru Nakazawa, Tatsuaki Okada, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Makoto Yoshikawa, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Tomohiro Usui, Toru Yada, Hisayoshi Yurimoto, Kazuhide Nagashima, Noriyuki Kawasaki, Naoya Sakamotoa, Ryuji Okazaki, Hikaru Yabuta, Hiroshi Naraoka, Kanako Sakamoto, Shogo Tachibana, Sei‐ichiro Watanabe, Yuichi Tsuda

    Meteoritics &amp; Planetary Science   59 ( 8 )   2002 - 2022   2024.01（ ISSN:1086-9379 ） （ eISSN:1945-5100 ）

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    Publishing type：Research paper (scientific journal)  

    Abstract

    Ryugu asteroid grains brought back to the Earth by the Hayabusa2 space mission are pristine samples containing hydrated minerals and organic compounds. Here, we investigate the mineralogy of their phyllosilicate‐rich matrix with four‐dimensional scanning transmission electron microscopy (4D‐STEM). We have identified and mapped the mineral phases at the nanometer scale (serpentine, smectite, pyrrhotite), observed the presence of Ni‐bearing pyrrhotite, and identified the serpentine polymorph as lizardite, in agreement with the reported aqueous alteration history of Ryugu. Furthermore, we have mapped the d‐spacings of smectite and observed a broad distribution of values, ranging from 1 to 2 nm, with an average d‐spacing of 1.24 nm, indicating significant heterogeneity within the sample. Such d‐spacing variability could be the result of either the presence of organic matter trapped in the interlayers or the influence of various geochemical conditions at the submicrometer scale, suggestive of a range of organic compounds and/or changes in smectite crystal chemistry.

    DOI： 10.1111/maps.14124

  • In-situ- and Residual- Strain State Characterization of Femtosecond Laser-Driven Shock Compressed Silicon

    Akira Higuchi, Takuo Okuchi, Yusuke Seto, Takahisa Shobu, Nobuhiko Nakanii, Yuichi Inubushi, Tadashi Togashi, Kohei Miyanishi, Kosuke Nagashio, Tomokazu Sano

    Conference on Lasers and Electro-Optics/Pacific Rim, CLEO-PR 2024 in Proceedings 2024 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR)   2024

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    Publishing type：Research paper (international conference proceedings)  

    Femtosecond laser-driven shock compression successfully induced compressive residual stress of 2GPa, which is about the yield stress, in silicon. Its high strain rates of 109/s are expected to suppress the brittle fracture of silicon.

  • In-situ- and Residual- Strain State Characterization of Femtosecond Laser-Driven Shock Compressed Silicon

    Higuchi A.

    Conference on Lasers and Electro-Optics/Pacific Rim, CLEO-PR 2024 in Proceedings 2024 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR)   2024

  • X-ray free electron laser observation of ultrafast lattice behaviour under femtosecond laser-driven shock compression in iron

    Sano T.

    Scientific Reports   13 ( 1 )   2023.12

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  • Influx of nitrogen-rich material from the outer Solar System indicated by iron nitride in Ryugu samples

    Toru Matsumoto, Takaaki Noguchi, Akira Miyake, Yohei Igami, Mitsutaka Haruta, Yusuke Seto, Masaaki Miyahara, Naotaka Tomioka, Hikaru Saito, Satoshi Hata, Dennis Harries, Aki Takigawa, Yusuke Nakauchi, Shogo Tachibana, Tomoki Nakamura, Megumi Matsumoto, Hope A. Ishii, John P. Bradley, Kenta Ohtaki, Elena Dobrică, Hugues Leroux, Corentin Le Guillou, Damien Jacob, Francisco de la Peña, Sylvain Laforet, Maya Marinova, Falko Langenhorst, Pierre Beck, Thi H. V. Phan, Rolando Rebois, Neyda M. Abreu, Jennifer Gray, Thomas Zega, Pierre-M. Zanetta, Michelle S. Thompson, Rhonda Stroud, Kate Burgess, Brittany A. Cymes, John C. Bridges, Leon Hicks, Martin R. Lee, Luke Daly, Phil A. Bland, Michael E. Zolensky, David R. Frank, James Martinez, Akira Tsuchiyama, Masahiro Yasutake, Junya Matsuno, Shota Okumura, Itaru Mitsukawa, Kentaro Uesugi, Masayuki Uesugi, Akihisa Takeuchi, Mingqi Sun, Satomi Enju, Tatsuhiro Michikami, Hisayoshi Yurimoto, Ryuji Okazaki, Hikaru Yabuta, Hiroshi Naraoka, Kanako Sakamoto, Toru Yada, Masahiro Nishimura, Aiko Nakato, Akiko Miyazaki, Kasumi Yogata, Masanao Abe, Tatsuaki Okada, Tomohiro Usui, Makoto Yoshikawa, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Satoru Nakazawa, Sei-ichiro Watanabe, Yuichi Tsuda

    Nature Astronomy   8 ( 2 )   207 - 215   2023.11（ eISSN:2397-3366 ）

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    Publishing type：Research paper (scientific journal)  

    Abstract

    Large amounts of nitrogen compounds, such as ammonium salts, may be stored in icy bodies and comets, but the transport of these nitrogen-bearing solids into the near-Earth region is not well understood. Here, we report the discovery of iron nitride on magnetite grains from the surface of the near-Earth C-type carbonaceous asteroid Ryugu, suggesting inorganic nitrogen fixation. Micrometeoroid impacts and solar wind irradiation may have caused the selective loss of volatile species from major iron-bearing minerals to form the metallic iron. Iron nitride is a product of nitridation of the iron metal by impacts of micrometeoroids that have higher nitrogen contents than the CI chondrites. The impactors are probably primitive materials with origins in the nitrogen-rich reservoirs in the outer Solar System. Our observation implies that the amount of nitrogen available for planetary formation and prebiotic reactions in the inner Solar System is greater than previously recognized.

    DOI： 10.1038/s41550-023-02137-z

    Other URL： https://www.nature.com/articles/s41550-023-02137-z

  • Mineralogy and petrology of fine‐grained samples recovered from the asteroid (162173) Ryugu

    Takaaki Noguchi, Toru Matsumoto, Akira Miyake, Yohei Igami, Mitsutaka Haruta, Hikaru Saito, Satoshi Hata, Yusuke Seto, Masaaki Miyahara, Naotaka Tomioka, Hope A. Ishii, John P. Bradley, Kenta K. Ohtaki, Elena Dobrică, Hugues Leroux, Corentin Le Guillou, Damien Jacob, Francisco de la Peña, Sylvain Laforet, Bahae‐Eddine Mouloud, Maya Marinova, Falko Langenhorst, Dennis Harries, Pierre Beck, Thi H. V. Phan, Rolando Rebois, Neyda M. Abreu, Jennifer Gray, Thomas Zega, Pierre‐M. Zanetta, Michelle S. Thompson, Rhonda Stroud, Kate Burgess, Brittany A. Cymes, John C. Bridges, Leon Hicks, Martin R. Lee, Luke Daly, Phil A. Bland, William A. Smith, Sam McFadzean, Pierre‐Etienne Martin, Paul A. J. Bagot, Dennis Fougerouse, David W. Saxey, Steven Reddy, William D. A. Rickard, Michael E. Zolensky, David R. Frank, James Martinez, Akira Tsuchiyama, Masahiro Yasutake, Junya Matsuno, Shota Okumura, Itaru Mitsukawa, Kentaro Uesugi, Masayuki Uesugi, Akihisa Takeuchi, Mingqi Sun, Satomi Enju, Aki Takigawa, Tatsuhiro Michikami, Tomoki Nakamura, Megumi Matsumoto, Yusuke Nakauchi, Masanao Abe, Satoru Nakazawa, Tatsuaki Okada, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Makoto Yoshikawa, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Tomohiro Usui, Toru Yada, Hisayoshi Yurimoto, Kazuhide Nagashima, Noriyuki Kawasaki, Naoya Sakamotoa, Peter Hoppe, Ryuji Okazaki, Hikaru Yabuta, Hiroshi Naraoka, Kanako Sakamoto, Shogo Tachibana, Sei‐ichiro Watanabe, Yuichi Tsuda

    Meteoritics &amp; Planetary Science   59 ( 8 )   1877 - 1906   2023.11（ ISSN:1086-9379 ） （ eISSN:1945-5100 ）

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    Publishing type：Research paper (scientific journal)  

    Abstract

    Samples returned from the carbonaceous asteroid (162173) Ryugu by the Hayabusa2 mission revealed that Ryugu is composed of materials consistent with CI chondrites and some types of space weathering. We report detailed mineralogy of the fine‐grained Ryugu samples allocated to our “Sand” team and report additional space weathering features found on the grains. The dominant mineralogy is composed of a fine‐grained mixture of Mg‐rich saponite and serpentine, magnetite, pyrrhotite, pentlandite, dolomite, and Fe‐bearing magnesite. These grains have mineralogy comparable to that of CI chondrites, showing severe aqueous alteration but lacking ferrihydrite and sulfate. These results are similar to previous works on large Ryugu grains. In addition to the major minerals, we also find many minerals that are rare or have not been reported among CI chondrites. Accessory minerals identified are hydroxyapatite, Mg‐Na phosphate, olivine, low‐Ca pyroxene, Mg‐Al spinel, chromite, manganochromite, eskolaite, ilmenite, cubanite, polydymite, transjordanite, schreibersite, calcite, moissanite, and poorly crystalline phyllosilicate. We also show scanning transmission electron microscope and scanning electron microscope compositional maps and images of some space‐weathered grains and severely heated and melted grains. Although our mineralogical results are consistent with that of millimeter‐sized grains, the fine‐grained fraction is best suited to investigate impact‐induced space weathering.

    DOI： 10.1111/maps.14093

  • Phyllosilicates with embedded Fe‐based nanophases in Ryugu and Orgueil

    Hugues Leroux, Corentin Le Guillou, Maya Marinova, Sylvain Laforet, Jean‐Christophe Viennet, Bahae‐Eddine Mouloud, Adrien Teurtrie, Francisco de la Peña, Damien Jacob, Daniel Hallatt, Mario Pelaez Fernandez, David Troadec, Takaaki Noguchi, Toru Matsumoto, Akira Miyake, Yohei Igami, Mitsutaka Haruta, Hikaru Saito, Satoshi Hata, Yusuke Seto, Masaaki Miyahara, Naotaka Tomioka, Hope A. Ishii, John P. Bradley, Kenta K. Ohtaki, Elena Dobrică, Falko Langenhorst, Dennis Harries, Pierre Beck, Thi H. V. Phan, Rolando Rebois, Neyda M. Abreu, Jennifer Gray, Thomas Zega, Pierre‐M. Zanetta, Michelle S. Thompson, Rhonda Stroud, Kate Burgess, Brittany A. Cymes, John C. Bridges, Leon Hicks, Martin R. Lee, Luke Daly, Phil A. Bland, Michael E. Zolensky, David R. Frank, James Martinez, Akira Tsuchiyama, Masahiro Yasutake, Junya Matsuno, Shota Okumura, Itaru Mitsukawa, Kentaro Uesugi, Masayuki Uesugi, Akihisa Takeuchi, Mingqi Sun, Satomi Enju, Aki Takigawa, Tatsuhiro Michikami, Tomoki Nakamura, Megumi Matsumoto, Yusuke Nakauchi, Masanao Abe, Satoru Nakazawa, Tatsuaki Okada, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Makoto Yoshikawa, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Tomohiro Usui, Toru Yada, Hisayoshi Yurimoto, Kazuhide Nagashima, Noriyuki Kawasaki, Naoya Sakamotoa, Ryuji Okazaki, Hikaru Yabuta, Hiroshi Naraoka, Kanako Sakamoto, Shogo Tachibana, Sei‐Ichiro Watanabe, Yuichi Tsuda

    Meteoritics &amp; Planetary Science   59 ( 8 )   1947 - 1965   2023.11（ ISSN:1086-9379 ） （ eISSN:1945-5100 ）

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    Publishing type：Research paper (scientific journal)  

    Abstract

    Samples were recently collected from the carbonaceous asteroid (162173) Ryugu, by the Japan Aerospace Exploration Agency (JAXA) Hayabusa2 mission. They resemble CI chondrites material, thus showing clear evidence of extensive aqueous alteration attested by the widespread presence of a mixture of serpentine and saponite. We present here a scanning transmission electron microscopy study of the Ryugu dominant lithology of the phyllosilicate matrix at the nanometer scale, which we compare with that of the Orgueil CI chondrite. In both objects, the phyllosilicates are of comparable nature and texture, consisting of a mixture of small‐sized crystallites of serpentine and saponite. At the micrometer scale or less, the texture is an alternation of fine and coarse domains. The fine‐grained regions are dominated by saponite. In Ryugu, they enclose numerous Fe,Ni nanosulfides, whereas in Orgueil, S‐ and Ni‐rich ferrihydrite is abundant. The coarse‐grained regions contain more serpentine and no or little Fe,Ni sulfides or ferrihydrite. Scanning transmission x‐ray microscopy at the Fe‐L<sub>3</sub> edge also reveals that iron valency of phyllosilicates is higher and more homogeneous in Orgueil (~70% Fe<sup>3+</sup>) than in Ryugu (&lt;50% Fe<sup>3+</sup>). We interpret the observed textures as being mostly a consequence of aqueous alteration, likely resulting from the replacement by phyllosilicates of submicrometric components, initially agglomerated by a primary accretion. The fine‐grained domains may result from the replacement of GEMS (GEMS—glass with embedded metal and sulfides) objects or from other types of nanometric assemblages of silicate and Fe‐based nanophases. On the other hand, the coarse‐grained regions may correspond to the replacement of anhydrous crystalline silicates of the olivine and pyroxene type. The major difference is the presence of Fe,Ni sulfides in Ryugu and of ferrihydrite and higher iron valency of phyllosilicates in Orgueil. This might be due to long‐term terrestrial weathering that would have destabilized the nanosulfides. We also explore an alternative scenario involving more oxidizing hydrothermal conditions on the Orgueil parent body.

    DOI： 10.1111/maps.14101

  • Strong phase coherence and vortex matter in a fractal system with proximity-induced superconductivity

    Nanami Teramachi, Iku Nakaaki, Aoi Hashimoto, Shuuichi Ooi, Minoru Tachiki, Shunichi Arisawa, Yusuke Seto, Takahiro Sakurai, Hitoshi Ohta, Jaroslav Valenta, Naohito Tsujii, Takao Mori, Takashi Uchino

    Physical Review B   108 ( 15 )   2023.10（ ISSN:24699950 ） （ eISSN:2469-9969 ）

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1103/PhysRevB.108.155146

    Other URL： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.108.155146/fulltext

  • A history of mild shocks experienced by the regolith particles on hydrated asteroid Ryugu

    Tomioka Naotaka, Yamaguchi Akira, Ito Motoo, Uesugi Masayuki, Imae Naoya, Shirai Naoki, Ohigashi Takuji, Kimura Makoto, Liu Ming-Chang, Greenwood Richard C., Uesugi Kentaro, Nakato Aiko, Yogata Kasumi, Yuzawa Hayato, Kodama Yu, Hirahara Kaori, Sakurai Ikuya, Okada Ikuo, Karouji Yuzuru, Okazaki Keishi, Kurosawa Kosuke, Noguchi Takaaki, Miyake Akira, Miyahara Masaaki, Seto Yusuke, Matsumoto Toru, Igami Yohei, Nakazawa Satoru, Okada Tatsuaki, Saiki Takanao, Tanaka Satoshi, Terui Fuyuto, Yoshikawa Makoto, Miyazaki Akiko, Nishimura Masahiro, Yada Toru, Abe Masanao, Usui Tomohiro, Watanabe Sei-ichiro, Tsuda Yuichi

    Nature Astronomy   7 ( 6 )   669 - 677   2023.06（ eISSN:23973366 ）

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    Micrometeorites, a possible major source of Earth’s water, are thought to form from explosive dispersal of hydrated chondritic materials during impact events on their parental asteroids. However, this provenance and formation mechanism have yet to be directly confirmed using asteroid returned samples. Here, we report evidence of mild shock metamorphism in the surface particles of asteroid Ryugu based on electron microscopy. All particles are dominated by phyllosilicates but lack dehydration textures, which are indicative of shock-heating temperatures below ~500 °C. Microfault-like textures associated with extensively shock-deformed framboidal magnetites and a high-pressure polymorph of Fe–Cr–sulfide have been identified. These findings indicate that the average peak pressure was ~2 GPa. The vast majority of ejecta formed during impact on Ryugu-like asteroids would be hydrated materials, larger than a millimetre, originating far from the impact point. These characteristics are inconsistent with current micrometeorite production models, and consequently, a new formation mechanism is required.

  • Search for High-Pressure Silicon Phases: Reaching the Extreme Conditions with High-Intensity Laser Irradiation Reviewed

    Ludovic Rapp, Takeshi Matsuoka, Konstantin L. Firestein, Daisuke Sagae, Hideaki Habara, Keiichiro Mukai, Kazuo A. Tanaka, Eugene Gamaly, Ryosuke Kodama, Yusuke Seto, Takahisa Shobu, Aki Tominaga, Lachlan Smillie, Bianca Haberl, Tatiana Pikuz, Toshinori Yabuuchi, Tadashi Togashi, Yuichi Inubushi, Makina Yabashi, Saulius Juodkazis, Dmitri V. Golberg, Andrei V. Rode, Norimasa Ozaki

    Springer Series in Optical Sciences   471 - 494   2023.04（ ISSN:0342-4111 ） （ ISBN:9783031147517 ） （ eISSN:1556-1534 ）

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    Publishing type：Part of collection (book)  

    DOI： 10.1007/978-3-031-14752-4_13

  • 3D morphological variability in foraminifera unravel environmental changes in the Baltic Sea entrance over the last 200 years

    Choquel C.

    Frontiers in Earth Science   11   2023.04

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  • Re-distribution of volatiles on the airless surface of the C-type carbonaceous asteroid Ryugu.

    Toru Matsumoto, Takaaki Noguchi, Akira Miyake, Yohei Igami, Mitsutaka Haruta, Yusuke Seto, Masaaki Miyahara, Naotaka Tomioka, Hikaru Saito, Satoshi Hata, Dennis Harries, Aki Takigawa, Yuusuke Nakauchi, Shogo Tachibana, Tomoki Nakamura, Megumi Matsumoto, Hope Ishii, John Bradley, Kenta Ohtaki, Elena Dobrică, Hugues Leroux, Corentin Le Guillou, Damien Jacob, Francisco de la Peña, Sylvain Laforet, Maya Marinova, Falko Langenhorst, Pierre Beck, Thi Phan, Rolando Rebois, Neyda Abreu, Jennifer Gray, Thomas Zega, Pierre-Marie Zanetta, Michelle Thompson, Rhonda Stroud, Katherine Burgess, Brittany Cymes, John Bridges, Leon Hicks, Martin Lee, Luke Daly, Phil Bland, Michael Zolensky, David Frank, James Martinez, Akira Tsuchiyama, Masahiro Yasutake, Junya Matsuno, Shota Okumura, Itaru Mitsukawa, Kentaro Uesugi, Masayuki Uesugi, Akihisa Takeuchi, Mingqi Sun, Satomi Enju, Tatsuhiro Michikami, Hisayoshi Yurimoto, Ryuji Okazaki, Hikaru Yabuta, Hiroshi Naraoka, Kanako Sakamoto, Toru Yada, Masahiro Nishimura, Aiko Nakato, Akiko Miyazaki, Kasumi Yogata, Masanao Abe, Tatsuaki Okada, Tomohiro Usui, Makoto Yoshikawa, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Satoru Nakazawa, Sei-ichiro Watanabe, Yuichi Tsuda

    2023.03

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  • Nonequilibrium Spherulitic Magnetite In The Ryugu Samples Reviewed

    Elena Dobrică, Hope A. Ishii, John P. Bradley, Kenta Ohtaki, Adrian J. Brearley, Takaaki Noguchi, Toru Matsumoto, Akira Miyake, Yohei Igami, Mitsutaka Haruta, Hikaru Saito, Satoshi Hata, Yusuke Seto, Masaaki Miyahara, Naotaka Tomioka, Hugues Leroux, Corentin Le Guillou, Damien Jacob, Francisco de la Peña, Sylvain Laforet, Maya Marinova, Falko Langenhorst, Dennis Harries, Pierre Beck, Thi H. V. Phan, Rolando Rebois, Neyda M. Abreu, Jennifer Gray, Thomas Zega, Pierre-M. Zanetta, Michelle S. Thompson, Rhonda Stroud, Kate Burgess, Brittany A. Cymes, John C. Bridges, Leon Hicks, Martin R. Lee, Luke Daly, Phil A. Bland, Michael E. Zolensky, David R. Frank, James Martinez, Akira Tsuchiyama, Masahiro Yasutake, Junya Matsuno, Shota Okumura, Itaru Mitsukawa, Kentaro Uesugi, Masayuki Uesugi, Akihisa Takeuchi, Mingqi Sun, Satomi Enju, Aki Takigawa, Tatsuhiro Michikami, Tomoki Nakamura, Megumi Matsumoto, Yusuke Nakauchi, Hisayoshi Yurimoto, Ryuji Okazaki, Hikaru Yabuta, Hiroshi Naraoka, Kanako Sakamoto, Shogo Tachibana, Toru Yada, Masahiro Nishimura, Aiko Nakato, Akiko Miyazaki, Kasumi Yogata, Masanao Abe, Tatsuaki Okada, Tomohiro Usui, Makoto Yoshikawa, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Satoru Nakazawa, Sei-ichiro Watanabe, Yuichi Tsuda

    Geochimica et Cosmochimica Acta   346   65 - 75   2023.02（ ISSN:0016-7037 ）

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    Publishing type：Research paper (scientific journal)  

    We have investigated several particles collected during each of two touchdowns of the Hayabusa2 spacecraft at the surface of the C-type asteroid 162173 Ryugu using various electron microscope techniques. Our detailed transmission electron microscopy study shows the presence of magnetite with various morphologies coexisting in close proximity. This is characteristic of CI chondrite-like materials and consistent with the mineral assemblages and compositions in the Ryugu parent body. We describe the microstructural characteristics of magnetite with different morphologies, which could have resulted from the chemical conditions (growth vs. diffusion rate) during their formation. Furthermore, we describe the presence of magnetites with a spherulitic structure composed of individual radiating fibers that are characterized by pervasive, homogeneously distributed euhedral to subhedral pores that have not been described in previous chondrite studies. This particular spherulitic structure is consistent with crystallization under nonequilibrium conditions. Additionally, the presence of a high density of defects within the magnetite fibers, the high surface/volume ratio of this morphology, and the presence of amorphous materials in several pores and at the edges of the acicular fibers further support their formation under nonequilibrium conditions. We suggest that the growth processes that lead to this structure result from the solution reaching a supersaturated state, resulting in an adjustment to a lower free energy condition via nucleation and rapid growth.

    DOI： 10.1016/j.gca.2023.02.003

  • A dehydrated space-weathered skin cloaking the hydrated interior of Ryugu

    Noguchi Takaaki, Matsumoto Toru, Miyake Akira, Igami Yohei, Haruta Mitsutaka, Saito Hikaru, Hata Satoshi, Seto Yusuke, Miyahara Masaaki, Tomioka Naotaka, Ishii Hope A., Bradley John P., Ohtaki Kenta K., Dobrică Elena, Leroux Hugues, Le Guillou Corentin, Jacob Damien, de la Peña Francisco, Laforet Sylvain, Marinova Maya, Langenhorst Falko, Harries Dennis, Beck Pierre, Phan Thi H. V., Rebois Rolando, Abreu Neyda M., Gray Jennifer, Zega Thomas, Zanetta Pierre-M., Thompson Michelle S., Stroud Rhonda, Burgess Kate, Cymes Brittany A., Bridges John C., Hicks Leon, Lee Martin R., Daly Luke, Bland Phil A., Zolensky Michael E., Frank David R., Martinez James, Tsuchiyama Akira, Yasutake Masahiro, Matsuno Junya, Okumura Shota, Mitsukawa Itaru, Uesugi Kentaro, Uesugi Masayuki, Takeuchi Akihisa, Sun Mingqi, Enju Satomi, Takigawa Aki, Michikami Tatsuhiro, Nakamura Tomoki, Matsumoto Megumi, Nakauchi Yusuke, Abe Masanao, Arakawa Masahiko, Fujii Atsushi, Hayakawa Masahiko, Hirata Naru, Hirata Naoyuki, Honda Rie, Honda Chikatoshi, Hosoda Satoshi, Iijima Yu-ichi, Ikeda Hitoshi, Ishiguro Masateru, Ishihara Yoshiaki, Iwata Takahiro, Kawahara Kousuke, Kikuchi Shota, Kitazato Kohei, Matsumoto Koji, Matsuoka Moe, Mimasu Yuya, Miura Akira, Morota Tomokatsu, Nakazawa Satoru, Namiki Noriyuki, Noda Hirotomo, Noguchi Rina, Ogawa Naoko, Ogawa Kazunori, Okada Tatsuaki, Okamoto Chisato, Ono Go, Ozaki Masanobu, Saiki Takanao, Sakatani Naoya, Sawada Hirotaka, Senshu Hiroki, Shimaki Yuri, Shirai Kei, Sugita Seiji, Takei Yuto, Takeuchi Hiroshi, Tanaka Satoshi, Tatsumi Eri, Terui Fuyuto, Tsukizaki Ryudo, Wada Koji, Yamada Manabu, Yamada Tetsuya, Yamamoto Yukio, Yano Hajime, Yokota Yasuhiro, Yoshihara Keisuke, Yoshikawa Makoto, Yoshikawa Kent, Fukai Ryohta, Furuya Shizuho, Hatakeda Kentaro, Hayashi Tasuku, Hitomi Yuya, Kumagai Kazuya, Miyazaki Akiko, Nakato Aiko, Nishimura Masahiro, Soejima Hiromichi, Suzuki Ayako I., Usui Tomohiro, Yada Toru, Yamamoto Daiki, Yogata Kasumi, Yoshitake Miwa, Connolly Harold C., Lauretta Dante S., Yurimoto Hisayoshi, Nagashima Kazuhide, Kawasaki Noriyuki, Sakamoto Naoya, Okazaki Ryuji, Yabuta Hikaru, Naraoka Hiroshi, Sakamoto Kanako, Tachibana Shogo, Watanabe Sei-ichiro, Tsuda Yuichi

    Nature Astronomy   7 ( 2 )   170 - 181   2023.02（ eISSN:23973366 ）

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    Without a protective atmosphere, space-exposed surfaces of airless Solar System bodies gradually experience an alteration in composition, structure and optical properties through a collective process called space weathering. The return of samples from near-Earth asteroid (162173) Ryugu by Hayabusa2 provides the first opportunity for laboratory study of space-weathering signatures on the most abundant type of inner solar system body: a C-type asteroid, composed of materials largely unchanged since the formation of the Solar System. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe³⁺ to Fe²⁺ and dehydration developed. Space weathering probably contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to weakening of the 2.7 µm hydroxyl (–OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7 µm band can signify space-weathering-induced surface dehydration, rather than bulk volatile loss.

  • A history of mild shocks experienced by the regolith particles on hydrated asteroid Ryugu

    Naotaka Tomioka, Akira Yamaguchi, Motoo Ito, Masayuki Uesugi, Naoya Imae, Naoki Shirai, Takuji Ohigashi, Makoto Kimura, Ming-Chang Liu, Richard C. Greenwood, Kentaro Uesugi, Aiko Nakato, Kasumi Yogata, Hayato Yuzawa, Yu Kodama, Kaori Hirahara, Ikuya Sakurai, Ikuo Okada, Yuzuru Karouji, Keishi Okazaki, Kosuke Kurosawa, Takaaki Noguchi, Akira Miyake, Masaaki Miyahara, Yusuke Seto, Toru Matsumoto, Yohei Igami, Satoru Nakazawa, Tatsuaki Okada, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Makoto Yoshikawa, Akiko Miyazaki, Masahiro Nishimura, Toru Yada, Masanao Abe, Tomohiro Usui, Sei-ichiro Watanabe, Yuichi Tsuda

    Nature Astronomy   7 ( 6 )   669 - 677   2023（ eISSN:2397-3366 ）

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    Publishing type：Research paper (scientific journal)  

    Abstract

    Micrometeorites, a possible major source of Earth’s water, are thought to form from explosive dispersal of hydrated chondritic materials during impact events on their parental asteroids. However, this provenance and formation mechanism have yet to be directly confirmed using asteroid returned samples. Here, we report evidence of mild shock metamorphism in the surface particles of asteroid Ryugu based on electron microscopy. All particles are dominated by phyllosilicates but lack dehydration textures, which are indicative of shock-heating temperatures below ~500 °C. Microfault-like textures associated with extensively shock-deformed framboidal magnetites and a high-pressure polymorph of Fe–Cr–sulfide have been identified. These findings indicate that the average peak pressure was ~2 GPa. The vast majority of ejecta formed during impact on Ryugu-like asteroids would be hydrated materials, larger than a millimetre, originating far from the impact point. These characteristics are inconsistent with current micrometeorite production models, and consequently, a new formation mechanism is required.

    DOI： 10.1038/s41550-023-01947-5

    Other URL： https://www.nature.com/articles/s41550-023-01947-5

  • A dehydrated space-weathered skin cloaking the hydrated interior of Ryugu Reviewed International coauthorship

    Takaaki Noguchi, Toru Matsumoto, Akira Miyake, Yohei Igami, Mitsutaka Haruta, Hikaru Saito, Satoshi Hata, Yusuke Seto, Masaaki Miyahara, Naotaka Tomioka, Hope A. Ishii, John P. Bradley, Kenta K. Ohtaki, Elena Dobrică, Hugues Leroux, Corentin Le Guillou, Damien Jacob, Francisco de la Peña, Sylvain Laforet, Maya Marinova, Falko Langenhorst, Dennis Harries, Pierre Beck, Thi H. V. Phan, Rolando Rebois, Neyda M. Abreu, Jennifer Gray, Thomas Zega, Pierre-M. Zanetta, Michelle S. Thompson, Rhonda Stroud, Kate Burgess, Brittany A. Cymes, John C. Bridges, Leon Hicks, Martin R. Lee, Luke Daly, Phil A. Bland, Michael E. Zolensky, David R. Frank, James Martinez, Akira Tsuchiyama, Masahiro Yasutake, Junya Matsuno, Shota Okumura, Itaru Mitsukawa, Kentaro Uesugi, Masayuki Uesugi, Akihisa Takeuchi, Mingqi Sun, Satomi Enju, Aki Takigawa, Tatsuhiro Michikami, Tomoki Nakamura, Megumi Matsumoto, Yusuke Nakauchi, Masanao Abe, Masahiko Arakawa, Atsushi Fujii, Masahiko Hayakawa, Naru Hirata, Naoyuki Hirata, Rie Honda, Chikatoshi Honda, Satoshi Hosoda, Yu-ichi Iijima, Hitoshi Ikeda, Masateru Ishiguro, Yoshiaki Ishihara, Takahiro Iwata, Kousuke Kawahara, Shota Kikuchi, Kohei Kitazato, Koji Matsumoto, Moe Matsuoka, Yuya Mimasu, Akira Miura, Tomokatsu Morota, Satoru Nakazawa, Noriyuki Namiki, Hirotomo Noda, Rina Noguchi, Naoko Ogawa, Kazunori Ogawa, Tatsuaki Okada, Chisato Okamoto, Go Ono, Masanobu Ozaki, Takanao Saiki, Naoya Sakatani, Hirotaka Sawada, Hiroki Senshu, Yuri Shimaki, Kei Shirai, Seiji Sugita, 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, Ryohta Fukai, Shizuho Furuya, Kentaro Hatakeda, Tasuku Hayashi, Yuya Hitomi, Kazuya Kumagai, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Hiromichi Soejima, Ayako I. Suzuki, Tomohiro Usui, Toru Yada, Daiki Yamamoto, Kasumi Yogata, Miwa Yoshitake, Harold C. Connolly Jr, Dante S. Lauretta, Hisayoshi Yurimoto, Kazuhide Nagashima, Noriyuki Kawasaki, Naoya Sakamoto, Ryuji Okazaki, Hikaru Yabuta, Hiroshi Naraoka, Kanako Sakamoto, Shogo Tachibana, Sei-ichiro Watanabe & Yuichi Tsuda

    2022.12

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    International / domestic magazine：International journal  

    DOI： 10.1038/s41550-022-0

  • A dehydrated space-weathered skin cloaking the hydrated interior of Ryugu

    Takaaki Noguchi, Toru Matsumoto, Akira Miyake, Yohei Igami, Mitsutaka Haruta, Hikaru Saito, Satoshi Hata, Yusuke Seto, Masaaki Miyahara, Naotaka Tomioka, Hope A. Ishii, John P. Bradley, Kenta K. Ohtaki, Elena Dobrică, Hugues Leroux, Corentin Le Guillou, Damien Jacob, Francisco de la Peña, Sylvain Laforet, Maya Marinova, Falko Langenhorst, Dennis Harries, Pierre Beck, Thi H. V. Phan, Rolando Rebois, Neyda M. Abreu, Jennifer Gray, Thomas Zega, Pierre-M. Zanetta, Michelle S. Thompson, Rhonda Stroud, Kate Burgess, Brittany A. Cymes, John C. Bridges, Leon Hicks, Martin R. Lee, Luke Daly, Phil A. Bland, Michael E. Zolensky, David R. Frank, James Martinez, Akira Tsuchiyama, Masahiro Yasutake, Junya Matsuno, Shota Okumura, Itaru Mitsukawa, Kentaro Uesugi, Masayuki Uesugi, Akihisa Takeuchi, Mingqi Sun, Satomi Enju, Aki Takigawa, Tatsuhiro Michikami, Tomoki Nakamura, Megumi Matsumoto, Yusuke Nakauchi, Masanao Abe, Masahiko Arakawa, Atsushi Fujii, Masahiko Hayakawa, Naru Hirata, Naoyuki Hirata, Rie Honda, Chikatoshi Honda, Satoshi Hosoda, Yu-ichi Iijima, Hitoshi Ikeda, Masateru Ishiguro, Yoshiaki Ishihara, Takahiro Iwata, Kousuke Kawahara, Shota Kikuchi, Kohei Kitazato, Koji Matsumoto, Moe Matsuoka, Yuya Mimasu, Akira Miura, Tomokatsu Morota, Satoru Nakazawa, Noriyuki Namiki, Hirotomo Noda, Rina Noguchi, Naoko Ogawa, Kazunori Ogawa, Tatsuaki Okada, Chisato Okamoto, Go Ono, Masanobu Ozaki, Takanao Saiki, Naoya Sakatani, Hirotaka Sawada, Hiroki Senshu, Yuri Shimaki, Kei Shirai, Seiji Sugita, 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, Ryohta Fukai, Shizuho Furuya, Kentaro Hatakeda, Tasuku Hayashi, Yuya Hitomi, Kazuya Kumagai, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Hiromichi Soejima, Ayako I. Suzuki, Tomohiro Usui, Toru Yada, Daiki Yamamoto, Kasumi Yogata, Miwa Yoshitake, Harold C. Connolly, Dante S. Lauretta, Hisayoshi Yurimoto, Kazuhide Nagashima, Noriyuki Kawasaki, Naoya Sakamoto, Ryuji Okazaki, Hikaru Yabuta, Hiroshi Naraoka, Kanako Sakamoto, Shogo Tachibana, Sei-ichiro Watanabe, Yuichi Tsuda

    Nature Astronomy   7 ( 2 )   170 - 181   2022.12（ eISSN:2397-3366 ）

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    Publishing type：Research paper (scientific journal)  

    Abstract

    Without a protective atmosphere, space-exposed surfaces of airless Solar System bodies gradually experience an alteration in composition, structure and optical properties through a collective process called space weathering. The return of samples from near-Earth asteroid (162173) Ryugu by Hayabusa2 provides the first opportunity for laboratory study of space-weathering signatures on the most abundant type of inner solar system body: a C-type asteroid, composed of materials largely unchanged since the formation of the Solar System. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe<sup>3+</sup> to Fe<sup>2+</sup> and dehydration developed. Space weathering probably contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to weakening of the 2.7 µm hydroxyl (–OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7 µm band can signify space-weathering-induced surface dehydration, rather than bulk volatile loss.

    DOI： 10.1038/s41550-022-01841-6

    Other URL： https://www.nature.com/articles/s41550-022-01841-6

  • Crystallinity in periodic nanostructure surface on Si substrates induced by near- and mid-infrared femtosecond laser irradiation Reviewed

    Reina Miyagawa, Daisuke Kamibayashi, Hirotaka Nakamura, Masaki Hashida, Heishun Zen, Toshihiro Somekawa, Takeshi Matsuoka, Hiroyuki Ogura, Daisuke Sagae, Yusuke Seto, Takahisa Shobu, Aki Tominaga, Osamu Eryu & Norimasa Ozaki

    2022.12

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    Publishing type：Research paper (scientific journal)   International / domestic magazine：International journal  

    DOI： 10.1038/s41598-022-2

  • Crystallinity in periodic nanostructure surface on Si substrates induced by near- and mid-infrared femtosecond laser irradiation Reviewed

    Reina Miyagawa, Daisuke Kamibayashi, Hirotaka Nakamura, Masaki Hashida, Heishun Zen, Toshihiro Somekawa, Takeshi Matsuoka, Hiroyuki Ogura, Daisuke Sagae, Yusuke Seto, Takahisa Shobu, Aki Tominaga, Osamu Eryu, Norimasa Ozaki

    Scientific Reports   12 ( 1 )   2022.12（ eISSN:2045-2322 ）

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    Publishing type：Research paper (scientific journal)  

    Abstract

    Laser-induced periodic surface structure (LIPSS), which has a period smaller than the laser wavelength, is expected to become a potential technique for fine surface processing. We report the microscopic and macroscopic observations of the crystallinity of LIPSSs, where the characteristics such as defects generation and residual strain were analyzed, respectively. The LIPSSs were formed on a Si substrate using two different femtosecond pulses from Ti:Sapphire laser with near-infrared wavelength (0.8 μm) and free-electron laser (FEL) with mid-infrared wavelength (11.4 μm). The photon energies of the former and latter lasers used here are higher and lower than the Si bandgap energies, respectively. These LIPSSs exhibit different crystalline states, where LIPSS induced by Ti:Sapphire laser show residual strain while having a stable crystallinity; in contrast, FEL-LIPSS generates defects without residual strain. This multiple analysis (microscopic and macroscopic observations) provides such previously-unknown structural characteristics with high spatial resolution. To obtain LIPSS with suitable properties and characteristics based on each application it is paramount to identify the laser sources that can achieve such properties. Therefore, identifying the structural information of the LIPSS generated by each specific laser is of great importance.

    DOI： 10.1038/s41598-022-25365-1

    Other URL： https://www.nature.com/articles/s41598-022-25365-1

  • High-pressure polymorphs in bulk silicon formed at relativistic laser intensity Reviewed

    Andrei Rode, Ludovic Rapp, Takeshi Matsuoka, Konstantin Firestein, Daisuke Sagae, Hideaki Habara, Keiichiro Mukai, Kazuo Tanaka, Eugene Gamaly, Ryosuke Kodama, Yusuke Seto, Takahisa Shobu, Aki Tominaga, Lachlan Smillie, Tatiana Pikuz, Bianca Haberl, Toshinori Yabuuchi, Tadashi Togashi Tadashi Togashi, Yuichi Inubushi, Makina Yabashi, Saulius Juodkazis, Dmitri Golberg, Norimasa Ozaki

    2022.11

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    Abstract

    Silicon polymorphs with exotic electronic and optical properties have recently attracted significant attention due to the wide range of useful bandgap characteristics1,2,3,4. They are typically formed by high pressure techniques, which put limitations on the sample volumes and their crystal structure5,6,7,8,9,10. This constitutes a major obstacle to study these polymorphs and their incorporation into existing technology. Here, we report on a new approach to create unusual crystal structures deep into the bulk of a silicon wafer by MeV-electrons generated by laser irradiation at ultra-relativistic intensity above ~2x10^18 W/cm2. Strong repulsion between the electrons, their branching due to self-generated magnetic field and nonlinear relativistic effects11,12,13 enhance deposition of their energy deep into the target and form high energy density conditions leading to ionisation, followed by fast quenching and restructuring into new crystal arrangements14,15,16,17,18. Analysis by Raman spectroscopy, synchrotron X-ray diffraction, and high-resolution transmission electron microscopy of nanocrystals formed in the irradiated samples provide compelling evidence of the formation of metastable Si phases. The unexplored domain of material transformations exposed to laser-produced MeV-electrons opens new pathways for the conversion into new crystal structures applicable to a wide range of materials at considerably larger quantity, all preserved for further studies and exploitation.

    DOI： 10.21203/rs.3.rs-2060424/v1

    Other URL： https://www.researchsquare.com/article/rs-2060424/v1.html

  • Phase transition and melting in zircon by nanosecond shock loading Reviewed

    Sota Takagi, Kouhei Ichiyanagi, Atsushi Kyono, Nobuaki Kawai, Shunsuke Nozawa, Norimasa Ozaki, Yusuke Seto, Takuo Okuchi, Souma Nitta, Satoru Okada, Kohei Miyanishi, Keiichi Sueda, Tadashi Togashi, Toshinori Yabuuchi

    Physics and Chemistry of Minerals   49 ( 5 )   2022.05（ ISSN:0342-1791 ） （ eISSN:1432-2021 ）

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1007/s00269-022-01184-8

    Other URL： https://link.springer.com/article/10.1007/s00269-022-01184-8/fulltext.html

  • <i>ReciPro</i>: free and open-source multipurpose crystallographic software integrating a crystal model database and viewer, diffraction and microscopy simulators, and diffraction data analysis tools Reviewed

    Yusuke Seto, Masahiro Ohtsuka

    Journal of Applied Crystallography   55 ( 2 )   397 - 410   2022.04（ ISSN:1600-5767 ） （ eISSN:1600-5767 ）

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    Authorship：Lead author   Publishing type：Research paper (scientific journal)  

    <italic>ReciPro</italic> is a comprehensive multipurpose crystallographic program equipped with an intuitive graphical user interface (GUI), and it is completely free and open source. This software has a built-in crystal database consisting of over 20 000 crystal models, and the visualization system can seamlessly display a specified crystal model as an attractive three-dimensional graphic. The comprehensive features are not confined to these crystal model databases and viewers. It can smoothly and quantitatively simulate not only single-crystal and/or polycrystalline (powder) diffraction patterns of X-ray, electron and neutron diffraction of a selected crystal model, based on the kinematic scattering theory, but also various electron diffraction patterns and high-resolution transmission electron microscopy (TEM) images, based on the dynamical scattering theory. The features of stereographic projection of crystal planes/axes to explore crystal orientation relationships and the semi-automatic diffraction spot indexing function for experimental diffraction patterns assist diffraction experiments and analyses. These features are linked through a user-friendly GUI, and the results can be synchronously displayed almost in real time. <italic>ReciPro</italic> will assist a wide range of crystallographers (including beginners) using X-ray, electron and neutron diffraction crystallography and TEM.

    DOI： 10.1107/s1600576722000139

  • Hugoniot equation-of-state and structure of laser-shocked polyimide C22H10N2O5 Reviewed

    K. Katagiri, N. Ozaki, D. Murayama, K. Nonaka, Y. Hironaka, Y. Inubushi, K. Miyanishi, H. Nakamura, T. Okuchi, T. Sano, Y. Seto, K. Shigemori, K. Sueda, T. Togashi, Y. Umeda, M. Yabashi, T. Yabuuchi, R. Kodama

    Physical Review B   105 ( 5 )   2022.02（ ISSN:2469-9950 ） （ eISSN:2469-9969 ）

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    Publishing type：Research paper (scientific journal)  

    The Hugoniot equation-of-state, Grüneisen parameter, and structure of laser-shocked polyimide were measured. The polyimide Hugoniots were measured in the pressure range 80-600 GPa and found to be consistent with the extrapolation of previously reported data below 60 GPa. The structural measurements of polyimide shock compressed to pressures of 28-163 GPa were performed using the in situ x-ray diffraction technique, and the results show that the melting pressure of polyimide along its Hugoniot is below 32(±3) GPa, indicating that the discontinuous volume change of the polyimide Hugoniot at ∼26 GPa observed in previous gas-gun experiments denotes the onset of melting. The consistency of the melting pressure between the previous gas-gun results and the present laser experiments suggests that the shock-melting process of polyimide is independent of the duration of the compression, revealing its rapid melting kinetics.

    DOI： 10.1103/physrevb.105.054103

    Other URL： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.105.054103/fulltext

  • Mineral Components of Scleractinian Coral Skeletons Cultured Without Symbionts Reviewed

    S. Motai, J. Kawano, S. Harii, Y. Seto, T. Watanabe, T. Nagai

    Journal of Geophysical Research: Biogeosciences   127 ( 2 )   2022.02（ ISSN:2169-8953 ） （ eISSN:2169-8961 ）

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    Publishing type：Research paper (scientific journal)  

    Skeletons of contemporary reef-building scleractinian corals are formed of aragonite, a polymorph of the calcium carbonate (CaCO3), notwithstanding calcite being a more stable phase under the condition of coral habitats. Circumstances developing aragonite in coral calcification have been addressed currently. Considering that the symbiotic relationship between the coral host and dinoflagellate algae (zooxanthellae) is perhaps relevant to coral calcification, we studied the impact of these symbiotic relationships on CaCO3 polymorph selection. Juvenile scleractinian corals (Acropora tenuis and Acropora digitifera) absent symbionts were cultured in seawaters with varied Mg/Ca molar ratios (mMg/Ca), and the mineral phases of the skeletons were detected employing X-ray diffraction. The findings revealed that diminutive quantities of calcite precipitated as coral skeleton in Acropora digitifera surprisingly in pseudo-present seawater (mMg/Ca similar to 5). Additionally, coral developed skeletons from only calcite in seawater with an mMg/Ca < 1. The evidence gathered in this investigation suggests that the symbiotic relationship affects the establishment of aragonite skeletons in the course of coral calcification.

    DOI： 10.1029/2021jg006574

    Other URL： https://onlinelibrary.wiley.com/doi/full-xml/10.1029/2021JG006574

  • Ultrafast olivine-ringwoodite transformation during shock compression Reviewed

    Takuo Okuchi, Yusuke Seto, Naotaka Tomioka, Takeshi Matsuoka, Bruno Albertazzi, Nicholas J. Hartley, Yuichi Inubushi, Kento Katagiri, Ryosuke Kodama, Tatiana A. Pikuz, Narangoo Purevjav, Kohei Miyanishi, Tomoko Sato, Toshimori Sekine, Keiichi Sueda, Kazuo A. Tanaka, Yoshinori Tange, Tadashi Togashi, Yuhei Umeda, Toshinori Yabuuchi, Makina Yabashi, Norimasa Ozaki

    Nature Communications   12 ( 1 )   4305   2021.12（ eISSN:2041-1723 ）

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    Publishing type：Research paper (scientific journal)  

    <title>Abstract</title>Meteorites from interplanetary space often include high-pressure polymorphs of their constituent minerals, which provide records of past hypervelocity collisions. These collisions were expected to occur between kilometre-sized asteroids, generating transient high-pressure states lasting for several seconds to facilitate mineral transformations across the relevant phase boundaries. However, their mechanisms in such a short timescale were never experimentally evaluated and remained speculative. Here, we show a nanosecond transformation mechanism yielding ringwoodite, which is the most typical high-pressure mineral in meteorites. An olivine crystal was shock-compressed by a focused high-power laser pulse, and the transformation was time-resolved by femtosecond diffractometry using an X-ray free electron laser. Our results show the formation of ringwoodite through a faster, diffusionless process, suggesting that ringwoodite can form from collisions between much smaller bodies, such as metre to submetre-sized asteroids, at common relative velocities. Even nominally unshocked meteorites could therefore contain signatures of high-pressure states from past collisions.

    DOI： 10.1038/s41467-021-24633-4

    PubMed

    Other URL： http://www.nature.com/articles/s41467-021-24633-4

  • Origin of minerals in åkermanite-rich patch texture and oxygen isotopic evolution of compact Type A Ca-Al-rich inclusions from the Northwest Africa 7865 CV chondrite Reviewed

    Akimasa Suzumura, Noriyuki Kawasaki, Yusuke Seto, Hisayoshi Yurimoto, Shoichi Itoh

    Geochimica et Cosmochimica Acta   303   51 - 65   2021.06（ ISSN:0016-7037 ） （ eISSN:1872-9533 ）

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    Publishing type：Research paper (scientific journal)  

    We report the in-situ oxygen isotopic distributions corresponding to the petrographic-mineralogical observation on a compact Type A (CTA) Ca-Al-rich inclusion (CAI), KU-N-02, from a reduced CV3 chondrite, Northwest Africa 7865. The CTA has an igneous texture and mainly consists of spinel, melilite, and Al-Ti-rich clinopyroxene (fassaite). Oxygen isotopic compositions of the constituent minerals plot along the carbonaceous chondrite anhydrous mineral line. The spinel grains are poikilitically enclosed in the melilite and fassaite and are uniformly 16O-rich (Δ17O = approximately − 23‰). The fassaite is texturally classified into two types: blocky fassaite and intergranular fassaite. The blocky fassaite crystals exhibit growth zoning as they change from Ti-rich to Ti-poor along the inferred directions of crystal growth from core to rim, while the oxygen isotopic compositions change from 16O-poor (Δ17O = approximately − 6‰) to 16O-rich (Δ17O = approximately − 23‰) with crystal growth. The intergranular fassaite crystals exist between the melilite crystals and exhibit variable Ti abundance and oxygen isotopic compositions. Additionally, their relationships between Ti contents and oxygen isotopic composition are similar to those of the blocky fassaite. The melilite grains are homogeneously 16O-poor (Δ17O = approximately − 2‰), irrespective of their åkermanite (Åk) content. Each melilite grain generally exhibits growth zoning with increasing Åk contents from core to rim, although the melilite contains Åk-rich patches within single crystal. Åk-rich patches often include two types of fassaite: small blebby crystals attached to spinel crystals and round crystals. The oxygen isotopic compositions of the Åk-rich patch and blebby fassaite are 16O-poor (Δ17O = approximately − 2‰), similar to that of the host melilite. On the other hand, the round fassaite exhibits significant variation in oxygen isotopic compositions ranging from Δ17O = −23‰ to − 4‰, which are different from those of the host melilite. These petrographic textures and oxygen isotopic variations indicate the presence of a solid precursor with variable oxygen isotopic compositions for the CTA. The spinel and round fassaite grains are relicts of the precursor that melted in the 16O-poor nebular gas, resulting in the crystallization of the host melilite from the 16O-poor melt. The Åk-rich patches and blebby fassaite crystallized from melts trapped by the growing host melilite crystals. The blocky and intergranular fassaite crystallized after the melilite did, and the oxygen isotopic composition of the melt changed to 16O-rich during the crystallization process, suggesting that the oxygen isotopic composition of the surrounding nebular gas could be varied. The inferred oxygen isotopic evolution for CTA is consistent with those inferred for Type B CAIs, suggesting that coarse-grained igneous CAIs formed in a similar nebular environment regardless of precursor chemistry.

    DOI： 10.1016/j.gca.2021.03.030

  • Magnetic susceptibility in the European Loess Belt: New and existing models of magnetic enhancement in loess Reviewed

    Balázs Bradák, Yusuke Seto, Thomas Stevens, Gábor Újvári, Katalin Fehér, Chiara Költringer

    Palaeogeography, Palaeoclimatology, Palaeoecology   569   110329 - 110329   2021.05（ ISSN:0031-0182 ）

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1016/j.palaeo.2021.110329

  • Liquid Structure of Tantalum under Internal Negative Pressure Reviewed

    K. Katagiri, N. Ozaki, S. Ohmura, B. Albertazzi, Y. Hironaka, Y. Inubushi, K. Ishida, M. Koenig, K. Miyanishi, H. Nakamura, M. Nishikino, T. Okuchi, T. Sato, Y. Seto, K. Shigemori, K. Sueda, Y. Tange, T. Togashi, Y. Umeda, M. Yabashi, T. Yabuuchi, R. Kodama

    Physical Review Letters   126 ( 17 )   175503   2021.04（ ISSN:0031-9007 ） （ eISSN:1079-7114 ）

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  • Fast deformation of shocked quartz and implications for planar deformation features observed in shocked quartz

    Toshimori Sekine, Tomoko Sato, Norimasa Ozaki, Kohei Miyanishi, Ryosuke Kodama, Yusuke Seto, Yoshinori Tange, Subodh C. Tiwari, Aiichiro Nakano, Priya Vashishta

    SHOCK COMPRESSION OF CONDENSED MATTER - 2019: Proceedings of the Conference of the American Physical Society Topical Group on Shock Compression of Condensed Matter   2272 ( 080002 )   2020.11

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    Publishing type：Research paper (international conference proceedings)  

    DOI： 10.1063/12.0000930

  • Magnetic fabric of loess and its significance in Pleistocene environment reconstructions Reviewed

    Balázs Bradák, Yusuke Seto, Martin Chadima, József Kovács, Péter Tanos, Gábor Újvári, Masayuki Hyodo

    Earth-Science Reviews   210   103385 - 103385   2020.11（ ISSN:0012-8252 ）

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1016/j.earscirev.2020.103385

  • Crystallographic preferred orientation of talc determined by an improved EBSD procedure for sheet silicates: Implications for anisotropy at the slab–mantle interface due to Si-metasomatism Reviewed

    Takayoshi Nagaya, Atsushi Okamoto, Ryosuke Oyanagi, Yusuke Seto, Akira Miyake, Masaoki Uno, Jun Muto, Simon R. Wallis

    American Mineralogist   105 ( 6 )   873 - 893   2020.06（ ISSN:0003-004X ） （ eISSN:1945-3027 ）

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    Publishing type：Research paper (scientific journal)  

    <title>Abstract</title>
    Talc is widely distributed over the Earth's surface and is predicted to be formed in various tectonic settings. Talc is a very soft and anisotropic sheet silicate showing very low friction behavior. Therefore, the formation of talc is expected to weaken the strength of talc-bearing rocks and may be associated with the initiation of subduction, and with a decrease in the coupling coefficient resulting in aseismic movements along faults and shear zones within subduction zones. For these reasons, understanding the crystallographic preferred orientation (CPO) of talc is important to quantify the anisotropy and physical properties of the host rock. However, it is difficult to measure a significant number of talc crystal orientations and to evaluate the accuracy of the measurements using electron-backscattered diffraction (EBSD). Therefore, talc CPO has not been reported, and there is uncertainty regarding the estimation of the strength of deformed talc-bearing rocks. Using methods developed for antigorite, we report the first successful EBSD measurements of talc CPO from a talc schist formed due to Simetasomatism of ultramafic rocks by subduction zone fluids. We used a combination of W-SEM and FE-SEM measurements to examine domains of various grain sizes of talc. In addition, we used TEM measurements to evaluate the accuracy of the EBSD measurements and discuss the results of talc CPO analysis. Talc CPO in the present study shows a strong concentration of the pole to the (001) plane normal to the foliation. The strongest concentration of the [100] direction is parallel to the lineation. The talc schist produces similar S-wave splitting and P- and S-wave anisotropy as antigorite schist in deeper domains, thus identifying talc-rich layers in subduction zones may require a combination of geophysical surveys, seismic observations, and anisotropy modeling. The presence of strong talc CPO in rocks comprising the slab–mantle interface boundary may promote spatial expansion of the slip area during earthquakes along the base of the mantle wedge.

    DOI： 10.2138/am-2020-7006

  • Collisional disruption of highly porous targets in the strength regime: Effects of mixture Reviewed

    Yuichi Murakami, Akiko M. Nakamura, Koki Yokoyama, Yusuke Seto, Sunao Hasegawa

    Planetary and Space Science   182   2020.03

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    Publishing type：Research paper (scientific journal)   International / domestic magazine：International journal  

    © 2019 Elsevier Ltd Highly porous small bodies are thought to have been ubiquitous in the early solar system. Therefore, it is essential to understand the collision process of highly porous objects when considering the collisional evolution of primitive small bodies in the solar system. To date, impact disruption experiments have been conducted using high-porosity targets made of ice, pumice, gypsum, and glass, and numerical simulations of impact fracture of porous bodies have also been conducted. However, a variety of internal structures of high-porosity bodies are possible. Therefore, laboratory experiments and numerical simulations in the wide parameter space are necessary. In this study, high-porosity targets of sintered hollow glass beads and targets made by mixing perlite with hollow beads were used in a collision disruption experiment to investigate the effects of the mixture on collisional destruction of high-porosity bodies. Among the targets prepared under the same sintering conditions, it was found that the targets with more impurities tend to have lower compressive strength and lower resistance against impact disruption. Further, destruction of the mixture targets required more impact energy density than would have been expected from compressive strength. It is likely that the perlite grains in the target matrix inhibit crack growth through the glass framework. The mass fraction of the largest fragment collapsed to a single function of a scaling parameter of energy density in the strength regime (Πs) when assuming ratios of tensile strength to compressive strength based on a relationship obtained for ice-silicate mixtures. However, the dependence on Πs is much larger than that shown for porous targets with different internal microstructures from the targets in this study. The depth of the deep cavity specific to the high-porosity target was well represented by a dimensionless parameter using the compressive strength of both the pure glass and mixture targets. The empirical relationship of cavity depth was shown to hold for various targets used in previous studies irrespective of the internal microstructure of the targets.

    DOI： 10.1016/j.pss.2019.104819

  • Proximity coupling of superconducting nanograins with fractal distributions Reviewed

    Takashi Uchino, Nanami Teramachi, Ryosuke Matsuzaki, Emi Tsushima, Shusuke Fujii, Yusuke Seto, Kazuyuki Takahashi, Takao Mori, Yutaka Adachi, Yukihito Nagashima, Yoshifumi Sakaguchi, Kazuki Ohishi, Akihiro Koda, Takahiro Sakurai, Hitoshi Ohta

    Physical Review B   101 ( 3 )   2020.01（ ISSN:2469-9950 ） （ eISSN:2469-9969 ）

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    Publishing type：Research paper (scientific journal)   International / domestic magazine：International journal  

    © 2020 American Physical Society. We explore the electrical and magnetic properties of a fractal assembly of Josephson junctions with transparent interfaces. For this purpose, we employ an Mg/MgO/MgB2 nanocomposite with ∼16 vol. % of MgB2 nanograins, which are distributed in a fractal manner in the normal matrix. Irrespective of the low volume fraction of MgB2 nanograins, the nanocomposite behaves as a bulk-like superconductor, i.e., zero resistivity, perfect diamagnetism, and strong vortex pinning. Thus, a global Josephson phase coherence is achieved in the nanocomposite. The lower (Hc1J) and higher (Hc2J) critical fields of the Josephson network are exceptionally high (Hc1J=96Oe and Hc2J=83.5kOe) as compared to those reported previously for granular superconductors. This will give an example of robust macroscopic superconducting coherence derived from long-range proximity coupling among fractally distributed superconducting nanograins through quantum interference of Andreev quasiparticles. Transverse-field muon spin rotation measurements reveal that the mean internal field in the superconducting mixed state increases with decreasing temperature below which the Josephson phase coherence sets in, opposite to the diamagnetic response observed in magnetization measurements. This unusual behavior implies a highly disordered and fluctuating nature of the Josephson vortices in the present superconducting nanocomposite.

    DOI： 10.1103/PhysRevB.101.035146

  • Significant pedogenic and palaeoenvironmental changes during the early Middle Pleistocene in Central Europe Reviewed

    B. Bradák, Y. Seto, J. Nawrocki

    Palaeogeography, Palaeoclimatology, Palaeoecology   534   109335 - 109335   2019.11（ ISSN:0031-0182 ）

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1016/j.palaeo.2019.109335

  • The hematite–goethite enhancement model of loess and an ‘irregular’ case from Paks, Hungary Reviewed International coauthorship

    B. Bradák, Y. Seto, D. Csonka, T. Végh, J. Szeberényi

    Journal of Quaternary Science   34 ( 4-5 )   299 - 308   2019.07（ ISSN:0267-8179 ） （ eISSN:1099-1417 ）

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.1002/jqs.3101

    Other URL： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/jqs.3101

  • X-ray Free Electron Laser (XFEL) Observation of Lonsdaleite Formation by Ultrafast Laser Shock Compression

    KATAGIRI Kento, OZAKI Norimasa, MATSUOKA Takahiro, MATSUOKA Takeshi, MIYANISHI Kohei, SETO Yusuke, UMEDA Yuhei, HOSOMI Minoru, MORIOKA Shintaro, INUBUSHI Yuichi, TOGASHI Tadashi, YABUUCHI Toshinori, YABASHI Makina, KODAMA Ryosuke

    The Review of Laser Engineering   47 ( 1 )   47   2019（ ISSN:0387-0200 ） （ eISSN:1349-6603 ）

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    We directly observed laser shock-induced, anomalous elastic compression of highly oriented pyrolytic
    graphite (HOPG) and subsequent phase transition to lonsdaleite at a longitudinal stress of ~30 GPa using
    an X-ray Free Electron Laser (XFEL). The observed phase transition is diffusionless and most likely
    relaxes a strong shear stress in the highly elastically compressed lattice. Our experimental results show
    that this diffusionless transformation depends on the mosaic spread of Highly Oriented Pyrlolytic
    Graphite (HOPG) samples.

    DOI： 10.2184/lsj.47.1_47

    CiNii Article

    Other URL： http://id.ndl.go.jp/bib/029483027

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MISC

  • Study on planetary materials under extreme conditions by shock compression method

    梅田悠平, 梅田悠平, 梅田悠平, 奥地拓生, 奥地拓生, 関根利守, 関根利守, 犬伏雄一, 犬伏雄一, 片桐健登, 片桐健登, 兒玉了祐, 兒玉了祐, 宮西宏併, 佐藤友子, 瀬戸雄介, 末田敬一, 富樫格, 富樫格, 富岡尚敬, 籔内俊毅, 籔内俊毅, 矢橋牧名, 矢橋牧名, 尾崎典雅, 尾崎典雅

    日本物理学会講演概要集(CD-ROM)   79 ( 1 )   2024（ ISSN:2189-079X ）

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  • Structual Evolution of Dynamically-compressed Amorphous Germanium Dioxide

    荒賀大翔, 梅田悠平, 瀬戸雄介, 樽谷洋之介, 奥地拓生

    KURNS-EKR (Web)   ( 19 )   2024（ ISSN:2434-1088 ）

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  • Corrigendum to “Origin of minerals in åkermanite-rich patch texture and oxygen isotopic evolution of compact Type A Ca-Al-rich inclusions from the Northwest Africa 7865 CV chondrite” [Geochim. Cosmochim. Acta 303 (2021) 51–65, (S0016703721002040), (10.1016/j.gca.2021.03.030)]

    Suzumura A.

    Geochimica et Cosmochimica Acta   362   2023（ ISSN:00167037 ）

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  • Structural Evolution of Dynamically-compressed Germanium Dioxide

    荒賀大翔, 荒賀大翔, 梅田悠平, 梅田悠平, 小林敬道, 遊佐斉, 瀬戸雄介, 奥地拓生, 奥地拓生

    日本鉱物科学会年会講演要旨(Web)   2023   2023

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  • Water molecule dynamics in amorphous silicate nanoparticles analyzed by quasielastic scattering

    奥地拓生, 富岡尚敬, 瀬戸雄介, 梅田悠平, 山田武, 玉造博夢, 柴田薫

    量子ビームサイエンスフェスタ(Web)   2021   2022

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  • Surface diffusion analysis of hydroxide minerals experiencing dehydration by quasi-elastic neutron scattering

    奥地拓生, 梅田悠平, 富岡尚敬, 瀬戸雄介, 山田武

    日本鉱物科学会年会講演要旨(Web)   2022   2022

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  • Hydration process of amorphous silicate nanoparticles analyzed by quasielastic neutron scattering at high temperature

    奥地拓生, 富岡尚敬, 瀬戸雄介, 梅田悠平, 山田武, 玉造博夢, 柴田薫

    日本鉱物科学会年会講演要旨(Web)   2021   2021

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  • Petrography and oxygen isotopic compositions of a compact Type A Ca-Al-inclusion from NWA 7865 reduced CV3 chondrite

    鈴村明政, 川崎教行, 瀬戸雄介, 圦本尚義, 圦本尚義, 伊藤正一

    日本地球惑星科学連合大会予稿集(Web)   2020   2020

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  • Compact Type A CAIに局所的に存在するAkermanite成分に富んだメリライトの成因

    鈴村明政, 川崎教行, 瀬戸雄介, 圦本尚義, 圦本尚義, 伊藤正一

    日本地球化学会年会要旨集(Web)   66th   2019

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  • ナノ多結晶ダイヤモンドのレーザー衝撃圧縮

    片桐健登, 尾崎典雅, 尾崎典雅, DRESSELHAUS-COOPER Leroa, EGGERT Jon, 犬伏雄一, 松岡健之, 宮西宏併, 宮西宏併, 森岡信太郎, 西山宣正, 関根利守, 瀬戸雄介, 丹下慶範, 入舩徹男, 入舩徹男, 富樫格, 梅田悠平, 梅田悠平, 矢橋牧名, 矢橋牧名, 籔内俊毅, 籔内俊毅, 兒玉了祐, 兒玉了祐

    高圧討論会講演要旨集   60th   2019（ ISSN:0917-6373 ）

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  • カンラン石及び同高圧相のレーザー衝撃圧縮時間分解その場X線回折

    奥地拓生, PUREVJAV Narangoo, 尾崎典雅, 尾崎典雅, 瀬戸雄介, 松岡健之, 梅田悠平, 片桐健登, 森岡信太朗, 富岡尚敬, 関根利守, 関根利守, 飯高敏晃, 薮内俊毅, 宮西宏併, 宮西宏併, 矢橋牧名, 兒玉了祐, 兒玉了祐

    高圧討論会講演要旨集   60th   2019（ ISSN:0917-6373 ）

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Presentations

  • 動力学的理論に基づく電子後方散乱回折のシミュレーション手法の開発と鉱物学への応用 Domestic conference

    瀬戸 雄介、大塚 真弘

    日本鉱物科学会 2024年会  2024.09  日本鉱物科学会

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    Presentation type：Oral presentation (general)  

    Venue：名古屋大学  

  • 動力学散乱理論に基づく電子後方散乱回折(EBSD)および高角度散乱暗視野像(HAADF)シミュレーションソフトウェアの開発

    瀬戸雄介

    日本地球惑星科学連合 2024年大会  2024.05  日本地球惑星科学連合

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    Presentation type：Poster presentation  

    Venue：幕張メッセ  

  • Phase transition and melting in zircon by nanosecond shock loading

    2021.10 

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    Presentation type：Poster presentation  

  • ベッセルビーム微小爆発による透明結晶内部での高圧物質凍結に 関する研究

    中村 浩隆, 小倉 広之, 上林 大介, 上村 拳生, 村山 大輔, RAPP Ludovic, GAMALY Eugene, RODE Andrei, 松岡 健之, 寒河江 大輔, 瀬戸 雄介, 菖蒲 敬久, 染川 智弘, 富永 亜希, PIKUZ Tatiana, 兒玉 了祐, 尾崎 典雅

    第62回高圧討論会  2021.10 

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    Presentation type：Poster presentation  

  • 衝撃圧縮下における多結晶体試料の格子歪み解析

    瀬戸 雄介

    第62回高圧討論会  2021.10 

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    Presentation type：Oral presentation (general)  

  • レーザー衝撃圧縮法で再現する高速天体衝突極限環境における含 水鉱物の高圧物性計測と時間分解構造観察

    梅田 悠平, 奥地 拓生, 関根 利守, 佐野 孝好, 犬伏 雄一, 片桐 健登, 兒玉 了祐, 宮西 宏併, 瀬戸 雄介, 清水 健二, 篠田 圭司, 末田 敬一, 富樫 格, 冨岡 尚敬, 藪内 俊毅, 尾崎 典雅

    第62回高圧討論会  2021.10 

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    Presentation type：Oral presentation (general)  

  • 高圧下における破壊現象の解明を目指した応力 ・ 歪の高速時分割 測定の技術開発

    大内 智博, 肥後 祐司, 丹下 慶範, 瀬戸 雄介, 入舩 徹男

    第62回高圧討論会  2021.10 

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    Presentation type：Oral presentation (general)  

  • X 線自由電子レーザーによるナノ多結晶ダイヤモンド超高速変形のその場観察

    片桐 健登, 尾崎 典雅, DRESSELHAUS-MARAIS Leora, EGGERT Jon H, 犬伏 雄一, 松岡 健之, 宮西 宏併, 西山 宣正, 末田 敬一, 関根 利守, 瀬戸 雄介, 丹下 慶範, 入舩 徹男, 富樫 格, 梅田 悠平, 矢橋 牧名, 籔内 俊毅, 兒玉 了祐

    第62回高圧討論会  2021.10 

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    Presentation type：Poster presentation  

  • レーザー衝撃圧縮による液体金属シリコンに関する研究

    尾崎 典雅, 佐藤 友子, 瀬戸 雄介, 新田 蒼真, 片桐健登, 中村 浩隆, 佐野 孝好, 兒玉 了祐, 奥地 拓生, 宮西 宏併, 末田 敬一, 冨樫 格, 犬伏 雄一, 籔内 俊毅, 矢橋 牧名, 大村 訓

    第62回高圧討論会  2021.10 

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    Presentation type：Oral presentation (general)  

  • 非晶質微粒子の高温水質変成過程の中性子準弾性散 乱

    奥地 拓生, 富岡 尚敬, 瀬戸 雄介, 梅田 悠平, 山田 武, 玉造 博夢, 柴田 薫

    日本鉱物科学会2021年会  2021.09 

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    Presentation type：Oral presentation (general)  

  • Microtexutural observations of TCIs in five CM carbonaceous chondrites and implications to aqueous environments on CM parent bodies

    Akane Iemoto, Yusuke Seto, Akira Miyake

    JpGU-AGU Joint meeting 2020  2020.07 

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    Presentation type：Poster presentation  

  • ナノ多結晶ダイヤモンドのレーザー衝撃圧縮 International coauthorship Domestic conference

    The 60th High Pressure Conference of Japan  2019.10 

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    Presentation type：Oral presentation (general)  

  • カンラン石及び同高圧相のレーザー衝撃圧縮時間分解その場X線回折 International coauthorship Domestic conference

    The 60th High Pressure Conference of Japan  2019.10 

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    Presentation type：Oral presentation (general)  

  • XFELを用いた衝撃誘起ナノ多結晶化プロセスの直接観察と展開 International coauthorship Domestic conference

    The 60th High Pressure Conference of Japan  2019.10 

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    Presentation type：Poster presentation  

  • XFELを用いた衝撃誘起ナノ多結晶化プロセスの直接観察 International coauthorship Domestic conference

    The 60th High Pressure Conference of Japan  2019.10 

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    Presentation type：Oral presentation (general)  

  • 衝撃圧縮された多結晶アルミナ中の差応力時間発展 Domestic conference

    The 60th High Pressure Conference of Japan  2019.10 

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    Presentation type：Oral presentation (general)  

  • 衝撃圧縮下におけるXFEL回折パターン解析手法の開発 Domestic conference

    The 60th High Pressure Conference of Japan  2019.10 

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    Presentation type：Oral presentation (general)  

  • フォルステライト単結晶のレーザー衝撃圧縮その場X線回折実験 Domestic conference

    2019.09 

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    Presentation type：Oral presentation (general)  

  • Precession electron diffraction法の鉱物への適用と評価 Domestic conference

    2019.09 

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    Presentation type：Oral presentation (general)  

  • 水質変質程度の異なるCMコンドライト中TCIの微細組織観察 Domestic conference

    2019.09 

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    Presentation type：Oral presentation (general)  

  • 深層学習による薄片画像の認識と岩石分類 Domestic conference

    2019.09 

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    Presentation type：Poster presentation  

  • 中性子散乱と透過電顕による含水鉱物の微視的な脱水過程の解析 Domestic conference

    2019.09 

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    Presentation type：Poster presentation  

  • 動力学効果を考慮した電子回折パターンの方位解析 Domestic conference

    2019.09 

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    Presentation type：Oral presentation (general)  

  • Petrographic study of a compact type A CAI with partial melting process International conference

    A. Suzumura, Y. Seto, S. Itoh

    The 82nd Annual Meeting of the Meteoritical Society  2019.07 

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    Presentation type：Poster presentation  

    Venue：Hokkaido University  

  • Nano-sized Magnetite and Hematite Inclusions in Muscovite Significantly Contribute to the Magnetic Enhancement of Loess–paleosol Deposits International conference

    HYODO MASAYUKI, SANO TAKURO, MATSUMOTO MEGUMI, SETO YUSUKE, SUZUKI KOTA, YANG TIANSHUI

    AOGS 16th Annual Meeting  2019.07 

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    Presentation type：Oral presentation (general)  

    Venue：Singapore  

  • Mineralogical study of TCIs in CM carbonaceous chondrites and implications to the formation processes International conference

    A. Iemoto, Y. Seto, A. Miyake

    The 82nd Annual Meeting of the Meteoritical Society  2019.07 

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    Presentation type：Poster presentation  

    Venue：Hokkaido University  

  • Development of GUI-based Software for Electron Diffraction Analyses Domestic conference

    瀬戸 雄介, 大塚 真弘, 伊神 洋平, 三宅 亮

    The 75th Annual Meeting of the Japanese Society of Microscopy  2019.06 

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    Presentation type：Poster presentation  

    Venue：Nagoya  

  • Mineralogical study of TCIs in CM carbonaceous chondrites Domestic conference

    Akane Iemoto, Yusuke Seto, Akira Miyake

    Japan Geoscience Union Meeting 2019  2019.05 

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    Presentation type：Oral presentation (general)  

    Venue：Makuhari Messe, Chiba  

  • Shock-compressed behavior of quartz by XFEL International conference

    Tomoko Sato, Yoshinori Tange, Yusuke Seto, Toshimori Sekine, Norimasa Ozaki, Toyohito Nishikawa, Kohei Miyanishi, Kensuke Matsuoka, Ryosuke Kodama, Tadashi Togashi, Yuichi Inubushi, Toshinori Yabuuchi, Makina Yabashi

    Japan Geoscience Union Meeting 2019  2019.05 

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    Presentation type：Poster presentation  

    Venue：Makuhari Messe, Chiba  

  • Linking occurrence and texture of dense silicate minerals in shocked meteorites with laser-shock experimental results of Mg2SiO4 analyzed by XFEL probe International conference

    Takuo Okuchi, Narangoo Purevjav, Norimasa Ozaki, Takeshi Matsuoka, Yusuke Seto, Yoshinori Tange, Toshinori Yabuuchi, Naotaka Tomioka, Toshimori Sekine, Ryosuke Kodama

    Japan Geoscience Union Meeting 2019  2019.05 

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    Presentation type：Oral presentation (general)  

    Venue：Makuhari Messe, Chiba  

  • Petrographic study of compact type A CAIs with partial melting process Domestic conference

    Akimasa Suzumura, Yusuke Seto, Shoichi Itoh

    Japan Geoscience Union Meeting 2019  2019.05 

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    Presentation type：Oral presentation (general)  

    Venue：Makuhari Messe, Chiba  

  • レス中白雲母が含有する大量の磁鉄鉱・赤鉄鉱ナノ粒子 Domestic conference

    HYODO MASAYUKI, 佐野拓郎, 松本恵, Seto Yusuke, 鈴木康太, 楊天水

    日本地球惑星科学連合2019年大会  2019.05  日本地球惑星科学連合

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    Presentation type：Oral presentation (general)  

    Venue：千葉  

  • Development of a software for electron diffraction simulation based on dynamical theory and its application to mineralogy Domestic conference

    Yusuke Seto, Masahiro Ohtuka, Akira Miyake

    Japan Geoscience Union Meeting 2019  2019.05 

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    Presentation type：Oral presentation (general)  

    Venue：Makuhari Messe, Chiba  

  • レスの帯磁率増加に寄与する白雲母含有の磁鉄鉱・赤鉄鉱ナノ粒子 Domestic conference

    HYODO MASAYUKI, 佐野 拓郎, 松本 恵, 鈴木 康太, Seto Yusuke, 楊天水

    平成30年度高知大学海洋コア総合研究センター共同利用・共同研究成果発表会  2019.03 

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    Presentation type：Oral presentation (general)  

    Venue：高知大学  

  • 高空隙率小天体模擬標的の衝突破壊実験：焼結温度の異なる混合物の影響 Domestic conference

    村上 雄一, 中村 昭子, 瀬戸 雄介, 長谷川 直

    平成30年度宇宙科学に関する室内実験シンポジウム  2019.02 

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    Presentation type：Oral presentation (general)  

    Venue：宇宙科学研究所  

  • 月面に存在する新たな水源

    鹿山雅裕, 富岡尚敬, 大谷栄治, 中嶋悟, 瀬戸雄介, 長岡央, FAGAN Timothy J, GӦTZE Jens, 三宅亮, 小澤信, 関根利守, 宮原正明, 松本恵, 庄田直起, 留岡和重

    日本地球惑星科学連合2016年大会  2016 

  • 水に富む月の上部マントル

    鹿山雅裕, 中嶋悟, 富岡尚敬, 瀬戸雄介, 大谷栄治, FAGAN Timothy J, 長岡央, 小澤信, 関根利守, 宮原正明, 三宅亮, 福田惇一, 留岡和重, 市村隼, 松本恵, 鈴木康太, GӦTZE Jens

    日本地球惑星科学連合2016年大会  2016 

  • MAC 88107隕石の微細組織：この隕石は本当に星雲集積岩か

    酒井 碧, 留岡和重, 瀬戸雄介, 三宅亮

    日本地球惑星科学連合2015年大会  2015 

  • NWA1232 CO3隕石中の熱変成度の異なる岩片を含む岩相

    松本 恵, 留岡 和重, 瀬戸 雄介, 山本 由紀子, 梅原 まり子, 三宅 亮, 浜根 大輔

    日本地球惑星科学連合2014年大会  2014 

  • コンドライト母天体におけるネフェリン形成条件の推定：水熱変成実験による溶液/岩石比と溶液pHへの制約

    市村 隼, 瀬戸 雄介, 留岡 和重, 三宅 亮

    日本地球惑星科学連合2013年大会  2013 

  • Yamato81020 CO3.0 コンドライトに含まれる層状ケイ酸塩鉱物に富むCI-like なクラスト

    森家 智嗣, 留岡 和重, 瀬戸 雄介, 三宅 亮

    日本地球惑星科学連合2013年大会  2013 

  • Allende隕石に含まれる特異なdark clastの微細組織：前駆岩相と変成履歴の推定

    酒井 碧, 留岡 和重, 瀬戸 雄介, 三宅 亮

    日本地球惑星科学連合2013年大会  2013 

  • Ningqiang隕石母天体におけるネフェリン形成プロセスの解明：透過型電子顕微鏡・放射光X線回折による研究

    松本 恵, 瀬戸雄介, 三宅亮, 留岡和重, 杉田光弘

    日本地球惑星科学連合2012年大会  2012 

  • Microstructure and its origin of isotopically anomalous material COS in the Acfer 094 carbonaceous chondrite

    SETO Yusuke, TOH Shoichi, SAKAMOTO Naoya, YURIMOTO Hisayoshi

    日本鉱物科学会年会講演要旨集  2010.09 

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Works

Grant-in-Aid for Scientific Research

  • Development of a new EBSD analysis method combining dynamical scattering theory and machine learning

    Grant-in-Aid for Scientific Research(B)  2026

  • Development of a new EBSD analysis method combining dynamical scattering theory and machine learning

    Grant-in-Aid for Scientific Research(B)  2025

  • Development of a new EBSD analysis method combining dynamical scattering theory and machine learning

    Grant-in-Aid for Scientific Research(B)  2024

  • 水熱実験による土壌性磁性鉱物の生成

    Grant-in-Aid for Scientific Research(C)  2024

Outline of education staff

  • 鉱物学・結晶学・隕石学・分析科学に関する理論と応用

Charge of on-campus class subject

  • 地球物質学1実習

    2024   Weekly class   Undergraduate

  • 地球物質学1

    2024   Weekly class   Undergraduate

  • 地球学演習A

    2024   Weekly class   Undergraduate

  • 地球物質学特論B

    2024   Weekly class   Graduate school

  • 地球進化学特別演習2A

    2024   Intensive lecture   Graduate school

  • 地球進化学特別演習1A

    2024   Intensive lecture   Graduate school

  • 地球学特別研究2A

    2024   Intensive lecture   Graduate school

  • 地球学特別研究1A

    2024   Intensive lecture   Graduate school

  • 地球進化学ゼミナールA

    2024   Intensive lecture   Graduate school

  • 地球学特別研究5A

    2024   Intensive lecture   Graduate school

  • 地球学特別研究4A

    2024   Intensive lecture   Graduate school

  • 地球学特別研究3A

    2024   Intensive lecture   Graduate school

  • 地球学基礎A

    2024   Weekly class   Graduate school

  • 現代科学と人間

    2024   Weekly class   Graduate school

  • 地球学演習Ⅳ

    2024   Intensive lecture   Undergraduate

  • 地球物質学2

    2024   Weekly class   Undergraduate

  • 地球学卒業演習

    2024   Intensive lecture   Undergraduate

  • 地球学野外実習1

    2024   Intensive lecture   Undergraduate

  • 測量及び地質調査法1実習

    2024   Intensive lecture   Undergraduate

  • 地質調査法1

    2024   Intensive lecture   Undergraduate

  • 海外特別研究1

    2024   Intensive lecture   Graduate school

  • 地球進化学特別講義A

    2024   Intensive lecture   Graduate school

  • 地球進化学特別演習2B

    2024   Intensive lecture   Graduate school

  • 地球進化学特別演習1B

    2024   Intensive lecture   Graduate school

  • 地球学特別研究2B

    2024   Intensive lecture   Graduate school

  • 地球学特別研究1B

    2024   Intensive lecture   Graduate school

  • 海外特別研究5

    2024   Intensive lecture   Graduate school

  • 海外特別研究5

    2024   Intensive lecture   Graduate school

  • 地球進化学ゼミナールB

    2024   Intensive lecture   Graduate school

  • 地球学特別研究5B

    2024   Intensive lecture   Graduate school

  • 地球学特別研究4B

    2024   Intensive lecture   Graduate school

  • 地球学特別研究3B

    2024   Intensive lecture   Graduate school

  • 地球学実験B

    2024   Weekly class   Graduate school

  • 海外特別研究

    2024   Intensive lecture   Undergraduate

  • 特別研究

    2024   Intensive lecture   Undergraduate

  • 地球物質学Ⅱ実習

    2024   Intensive lecture   Undergraduate

▼display all

Charge of off-campus class subject

  • 惑星物質科学2

    Institution：Kobe University

  • 惑星物質科学1

    Institution：Kobe University

  • 惑星物質科学

    Institution：Kobe University

  • 惑星学実習Ｅ1

    Institution：Kobe University

  • 惑星学実習Ｄ

    Institution：Kobe University

  • 惑星学基礎Ⅴ演習

    Institution：Kobe University

  • Planetary Material Science 2

    Institution：Kobe University

  • Planetary Material Science 1

    Institution：Kobe University

  • Planetary Material Science

    Institution：Kobe University

  • Experimental Training in Planetology Science E1

    Institution：Kobe University

  • Experimental Training in Planetology Science D

    Institution：Kobe University

  • Exercise of Fundamental Planetology V

    Institution：Kobe University

▼display all

Faculty development activities

  • オープンキャンパス　模擬実験  2023

    　More details

    8月に開催されたオープンキャンパスにおいて、高校生を対象に鉱物の肉眼鑑定実習を行った。

  • 2023年度 公大授業  2023

    　More details

    高校生を対象に、地球外物質の種類や性質、およびそれらから読み解かれる太陽系と地球の歴史を解説した。

Number of instructed thesis, researches

  • 2023

    Number of instructed the graduation thesis：1  Number of graduation thesis reviews：1

    [Number of instructed the Master's Program] (previous term)：0  [Number of instructed the Master's Program] (letter term)：0

    [Number of master's thesis reviews] (chief)：0  [Number of master's thesis reviews] (vice-chief)：0

    [Number of doctoral thesis reviews] (chief)：0  [Number of doctoral thesis reviews] (vice-chief)：0