金属材料組織観察のための透過電子顕微鏡技法の開発と応用

電子線トモグラフィーによる格子欠陥の３次元可視化

高傾斜３軸試料ホルダーとその応用

3D Visualization of Dislocation Arrangements in Austenitic Stainless Steel with Dual-Axis STEM Tomography

オーステナイト系ステンレス鋼における全転位の３次元可視化

SrAl2O4系応力発光材料に導入された面欠陥の透過型電子顕微鏡観察

応力発光材料SrAl2O4:Eu2+における双晶界面の高分解能電子顕微鏡観察

EDS Analysis and Electron Tomography of New Precipitates on Lath Boundaries in 10Cr Ferritic Heat-Resistant Steel with V

V添加高強度耐熱鋼におけるラス境界析出物のEDS分析と3次元形態観察

Hybrid Electron Tomography Observation of Phase Separation in Ni-Al-Ti Superalloy

Ni-Al-Ti合金におけるγ’析出粒子の相分離組織の３次元TEM解析（Three-dimensional TEM analysis of phase separation of γ' particles in Ni-Al-Ti alloy）

The sleeping woman in the woods

Tomographic Dark-Field TEM Observation of Ordered Precipitates in Ni-Mo Alloy

暗視野TEMトモグラフィーによる合金中の規則バリアントの３次元形態観察

単結晶組成傾斜法と集束イオンビーム・マイクロサンプリング法によるAl-rich TiAl中の長周期規則構造の解析

高分解能電子顕微鏡像の定量評価による合金の短範囲規則構造の研究

Ni-Mo合金の短範囲−長範囲規則化過程の微視的機構に関する研究

Publishing type：Research paper (scientific journal)  

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-L3 edge also reveals that iron valency of phyllosilicates is higher and more homogeneous in Orgueil (~70% Fe3+) than in Ryugu (<50% Fe3+). 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

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

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The effect of hydrogen charging duration on the transformation behavior, microstructural evolution, and dynamic microstructural changes associated with thermoelastic martensitic transformation in Ti–Ni shape memory alloy was investigated. Compared with the uncharged specimen, the martensitic transformation start (M_s) and reverse transformation finish (A_f) temperatures increased with charging time, whereas the martensitic transformation finish and reverse transformation start temperatures remained almost unchanged. In situ SEM results were consistent with these behaviors. Upon cooling, the transformation progressed from the center to the surface in charged specimens, indicating a higher transformation temperature in the center than the surface. The latent heat of transformation decreased with increasing charging time, quantitatively attributed to an untransformed region consisting of hydrogen-induced martensite and a hydrogen-affected layer. The hydrostatic effect from those layers on the interior B2 phase was proposed as the origin of the increased M_s and A_f temperatures.

DOI： 10.1007/s40830-024-00495-9

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Other Link： https://link.springer.com/article/10.1007/s40830-024-00495-9/fulltext.html

Publisher：Meteoritics and Planetary Science  

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

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DOI： 10.1093/jmicro/dfae008

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Metals and Materials  

<p>Microstructure and its evolution of solute-enriched stacking faults (SESFs) in kink-deformed Mg–Zn–Y alloys have been investigated by scanning transmission electron microscopy (STEM). Mass-thickness contrast in annular dark-field (ADF) STEM images and diffraction contrast in weak-beam dark-field (WBDF) STEM images visualized locations of solute-enriched regions and dislocations, respectively. Most of the SESFs are located at or near kink boundaries, and a variety of arrangements and morphology of the SESFs are followed by dislocations with the <i>c</i> component of α-Mg matrix and small-angle lattice rotations along the <i>c</i>-axis as well as the <i>a</i>-<i>b</i> axes. As notable microstructural features of the SESFs, rectangular-shaped and step-shaped arrangements of the SESFs, observed respectively before and after a heat treatment at 573 K for 168 h, were observed in detail, and their formation processes were discussed.</p>

DOI： 10.2320/matertrans.mt-m2023186

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In this study, the microstructure of polycrystalline Co-doped BaFe2As2 superconducting bulks was comprehensively analyzed. The synthesis process involved ball milling and subsequent spark plasma sintering (SPS). A strong correlation between the microstructure and synthesis conditions was observed. Specifically, when mechanochemical synthesis of raw metal powders was carried out at a ball milling energy (EBM) of 100 MJ/kg, the resulting Co-BaFe2As2 bulk contained nanograins with a high density of planar defects and exhibited a high critical current density (Jc) under both magnetic and self-fields. The findings suggest that planar defects are one of the influential factors on the superconducting properties. Atomic-resolution microstructural characterization revealed that the planar defects are parallel to (001) and exhibit distinctive atomic arrangements. Atomic-resolution elemental mappings displayed a remarkable barium concentration in planar defects and grain boundaries compared to the BaFe2As2 matrix. Local strain fields were also observed around planar defects, especially near their edges. These nanoscale strain fields could be considered as volumetric pinning centers, and effectively pin flux vortices in the random crystal orientation, thereby increasing Jc in the Fe-based superconducting bulk. Additionally, an extended investigation was performed to include a K-doped BaFe2As2 bulk that exhibits similar planar defects. Based on the results of the microstructural analysis, speculations were mode on the evolution process of the microstructure during the preparation of BaFe2As2 bulks.

DOI： 10.1016/j.actamat.2024.119648

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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.

DOI： 10.1038/s41550-023-02137-z

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Language：English  

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.

CiNii Research

Publishing type：Research paper (scientific journal)  

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

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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

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Herein, the crystallization behavior of a Li2O–Al2O3–SiO2 (LAS) glass system with the addition of ZrO2 and SnO2 as nucleating agents was investigated using X-ray diffraction, differential scanning calorimetry, four-dimensional scanning transmission electron microscopy, and X-ray absorption fine-structure measurements. At lower heat-treatment temperatures, the addition of ZrO2 and SnO2 afforded a ZrSnO4 solid solution (SS), whereas at higher heat-treatment temperatures, the ZrSnO4 SS decomposed, affording tetragonal ZrO2 and tetragonal SnO2. LAS-based crystalline phases, such as β-quartz and β-spodumene phases SS, were formed after the formation of the ZrSnO4 SS. ZrSnO4 SS particles a few nanometers in size were present in contact with the β-quartz SS particles a few dozen nanometers in size. This suggests that the ZrSnO4 SS served as a crystal nucleus for the β-quartz SS, promoting its growth.

DOI： 10.1111/ijag.16644

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

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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 (CH_n), 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

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Language：Japanese   Publisher：The Japanese Association for Crystal Growth  

<p>  Metal nanoparticles undertake sintering at a lower temperature compared to their bulk counterparts, attracting great attention in industrial applications such as printed electronics. Since nanoparticles are easy to aggregate, the three-dimensional (3D) visualization of their sintering process plays a vital role in quantifying the morphological changes during heating. However, the nanoparticles are sensitive to surface contamination, resulting in poor affinity to the 3D visualization with conventional electron beam intensity because the visualization technique requires a long beam exposure time, potentially making beam induced contamination significant. In this paper, we demonstrate our developed 3D observation scheme, including advanced image processing techniques. A sample transfer system, which enables to prevent nanoparticles from being exposed to air, and an ultra-low-electron dose observation protocol prevents surface contamination during the observation. The low-signal-to-noise ratio of acquired images is compensated by the advanced image processing techniques. The obtained 3D images of nanoparticles enable to measure the neck growth and variation of particle distance in 3D during the sintering in a quantitative way.</p>

DOI： 10.19009/jjacg.51-1-03

CiNii Research

Publishing type：Research paper (scientific journal)  

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

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

It has been reported that functional and mechanical properties of Ti-Ni shape memory alloys could be degraded by hydrogen absorption. Many studies have indicated the formation of a hardened layer on the surface in hydrogen-absorbed Ti-Ni alloys. However, the underlying microstructural features and their impact on the functional and mechanical properties remain unclear. In the present study, ex situ and in situ electron microscopy characterizations of the high-hardness layer in a hydrogen-charged Ti-Ni alloy were performed for the first time. Electron diffraction and atomic resolution imaging revealed that the hardened layers have an orthorhombic structure with a four-layer stacking sequence and a martensitic-like crystallographic nature such as lattice correspondence including 12 variants of the orthorhombic phase against each orientation of the parent cubic (B2) phase. In situ and ex situ observations in an electron microscope confirmed that the orthorhombic phase undergoes athermal transformation upon cooling and stress- and/or strain-induced transformation upon deformation, which further characterizes the martensitic-like nature of this phase. The effect of hydrogen on the original phase transformation from the cubic (B2) to the monoclinic (B19′) structure is also discussed.

DOI： 10.1016/j.jallcom.2023.171470

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Highly luminescent red emitting Zn2+ modified Gd2O3:Eu3+, Li + nanophosphors with superior colour purity were prepared by the organic mediated solvothermal combustion of metal-citrates in diethylene glycol. Structure, morphology, spectroscopic and luminescence dynamics of the nanophosphors were found to be sensitive to Zn2+ concentration. Simultaneous incorporation by Zn2+ and Li+ ions in Gd2O3:Eu3+ resulted in better emission features and improved photophysical radiative properties. Enhanced photoemission has resulted from the cooperative and combined roles caused by Li+ and Zn2+ ions, improvement of crystallinity, modifications of the crystal field and reduced symmetry around Eu3+ ions in Gd2O3. Photoemission intensity of the optimal zinc compensated phosphor with composition Gd1.71Eu0.1Li0.15Zn0.04O3 was found to be 1.82 times that of Gd1.75Eu0.1Li0.15O3 and it exhibited a lifetime of 1.467 ms with the highest colour purity of 97.06 %. Luminescence decay profiles of all the synthesized phosphors were found to follow single exponential behaviour. Judd-Ofelt analysis revealed that the emission intensity parameters were found to be optimum for Gd1.71Eu0.1Li0.15Zn0.04O3 phosphor, indicating the highest asymmetry of local environment around Eu3+ ions in this material. Better radiative and Judd-Ofelt intensity parameters obtained indicate that this highly luminescent red emitting phosphor can act as a promising material for high resolution phosphor coated displays, deep UV excited phosphor converted LEDs and for developing defence security inks.

DOI： 10.1016/j.jlumin.2023.120150

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Language：Others   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers ({IEEE})  

For obtaining microscopic knowledge toward a fabrication process of (Bi,Pb)2Sr2Ca2Cu3Ox (Bi,Pb-2223) single-phase material, we fabricated a multilayered film on a SrTiO3(001) substrate by a sputtering method using (Bi,Pb)2Sr2CaCu2Oy (Bi,Pb-2212) and Pb-Ca-Cu-O targets alternately at 650 °C. The as-grown film was an epitaxially grown multilayered film consisting of Bi,Pb-2212 and Pb-Ca-Cu-O layers. Coarse grains of impurity phases were also formed within the multilayered film, and these impurity phases were difficult to eliminate even after heat treatments. After 10 h heat treatment at 840 °C with Bi,Pb-2223 pellets, the phase transition from Bi,Pb-2212 to Bi,Pb-2223 occurred in the multilayered film. The phase transition to Bi,Pb-2223 proceeded preferentially at the interface with the impurity phases and the Pb-Ca-Cu-O layers. These observation results suggest that the impurity phases promote three-dimensional atomic diffusion in the multilayered film to accelerate the phase transition to Bi,Pb-2223, as well as consume constituent elements, Ca, Cu and O. Even after the 100 h heat treatment at 840 °C with Bi,Pb-2223 pellets, the phase transition from Bi,Pb-2212 to Bi,Pb-2223 did not proceed completely, and the fraction of the Bi,Pb-2223 phase in the whole superconducting phases was ∼50%. It is suggested that controlling the formation and microstructure of the impurity phases is a key to further increasing the fraction of the Bi,Pb-2223 phase.

DOI： 10.1109/TASC.2023.3259920

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It is known that the addition of Li2O to 33.3BaO-66.7SiO2 glass, whose composition is the same as BaSi2O5, promotes crystallization of BaSi2O5. In this study, in order to clarify the effect of a smaller amount of Li2O, xLi2O-(30-x)BaO-70SiO2[mol%] (x = 0, 0.2, 0.5) glasses were prepared. The main crystalline phases in the heat treatments near the maximum crystallization peak temperature, were high-BaSi2O5 and low-BaSi2O5 which transformed from high-BaSi2O5. It is found that the introduction of only 0.2 mol% and 0.5 mol% Li2O significantly changes the crystallization behavior. In the composition without Li2O, only high-BaSi2O5 was formed after heat treatment even for 24 h. For compositions containing Li2O, low-BaSi2O5 was formed within 1 h of heat treatment. In these compositions, it is found that the addition of Li2O enhances phase separation in the early stage of heat treatment, resulting in the formation of Si-rich droplet phases and Ba-rich phases. The composition of the Ba rich glass phase would be close to the stoichiometric composition of BaSi2O5, suggesting a significant change in crystallization behavior.

DOI： 10.1111/jace.19099

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Language：English   Publishing type：Research paper (scientific journal)  

The nanoscale characterization of thermally activated solid reactions plays a pivotal role in products manufactured by nanotechnology. Recently, in situ observation in transmission electron microscopy combined with electron tomography, namely four-dimensional observation for heat treatment of nanomaterials, has attracted great interest. However, because most nanomaterials are highly reactive, i.e., oxidation during transfer and electron beam irradiation would likely cause fatal artefacts; it is challenging to perform the artifact-free four-dimensional observation. Herein, we demonstrate our development of a novel in situ three-dimensional electron microscopy technique for thermally activated solid-state reaction processes in nanoparticles (NPs). The sintering behaviour of Cu NPs was successfully visualized and analyzed in four-dimensional space-time. An advanced image processing protocol and a newly designed state-of-the-art MEMS-based heating holder enable the implementation of considerably low electron dose imaging and prevent air exposure, which is of central importance in this type of observation. The total amount of electron dose for a single set of tilt-series images was reduced to 250 e− nm−2, which is the lowest level for inorganic materials electron tomography experiments. This study evaluated the sintering behaviour of Cu NPs in terms of variations in neck growth and particle distance. A negative correlation between the two parameters is shown, except for the particle pair bound by neighbouring NPs. The nanoscale characteristic sintering behavior of neck growth was also captured in this study.

DOI： 10.1039/D3NR00992K

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Language：Others   Publisher：IOP Publishing  

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Since the discovery of Fe-based superconductors, a lot of effort has been devoted to growing single crystals and epitaxial thin films of them for fundamental studies and applied research of superconductivity. As a result, epitaxial thin films of the most of Fe-based superconductors have been realized. However, some of the materials, namely pristine and transition-metal-doped (Li,Fe)OHFeSe, hydrogen-doped LnFeAsO (Ln = Nd and Sm), Co-doped SmFeAsO, and K-doped BaFe₂As₂ have been available only in the form of single crystals due to, e.g. the difficulty in doping hydrogen, obtaining high-quality sintered bulks for the target used for pulsed laser deposition, and controlling volatile elements. By solving those issues, the aforementioned compounds have been successfully fabricated as epitaxial thin films in recent years. Unlike single crystals, transport critical current measurements are relatively easy on thin films, which can help evaluate the application potential. In this article, we give an overview over the growth methods for epitaxial thin films of those compounds, followed by their physical properties, especially focusing on electrical transport.

DOI： 10.1088/1361-6668/acccb2

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Other Link： https://iopscience.iop.org/article/10.1088/1361-6668/acccb2/pdf

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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

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Electron tomography (ET) is a powerful tool for elucidating the properties and functionalities of materials. The innovative development of aberration-corrected electron microscopy in the early 21st century and the remarkable progress in the development of detectors, equipment and devices related to ET have resulted in substantial improvements in resolution. However, not only advances in hardware but also remarkable developments in reconstruction algorithms and related three-dimensional (3D) analysis methods have contributed to the resolution improvements. ET has its own problems, including the missing-wedge problem due to the limited tilt-angle range and the need to acquire numerous specimen-tilt images, the latter of which is time-consuming and can potentially damage the specimen. This review paper aims to (i) describe the established basic theories and definitions regarding 3D resolution of ET and practical 3D resolution measurement methods, (ii) discuss various reconstruction algorithms that effectively overcome the aforementioned problems and (iii) describe recent progress in the core of ET applications in materials science with respect to atomic ET, analytical ET and in-situ ET. The aforementioned ET problems have been addressed with each method developed in each field of application. Notably, in terms of aim (ii), recently developed reconstruction algorithms can reduce the number of projection images (specimen-tilt images) needed to attain a certain resolution without violating the Nyquist criterion. This approach is interpreted as a novel non-linear sampling theorem.

DOI： 10.1093/jmicro/dfac071

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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.

DOI： 10.1038/s41550-022-01841-6

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Language：English  

DOI： 10.1073/pnas.2203628119

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

Abstract

Molecular beam epitaxy of K-doped Ba122 (Ba_1−xK_xFe₂As₂) superconductor was realized on an MgO substrate. Microstructural observation revealed that the undoped Ba122 served as a perfect buffer layer for epitaxial growth of the K-doped Ba122. The film exhibited a high critical temperature of 39.8 K and a high critical current density of 3.9 MA cm⁻² at 4 K. The successful growth of epitaxial thin film will enable artificial single grain boundary on oxide bicrystal substrates and reveal the grain boundary transport nature of K-doped Ba122.

DOI： 10.1088/1361-6668/ac8025

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Other Link： https://iopscience.iop.org/article/10.1088/1361-6668/ac8025/pdf

Language：Others   Publishing type：Research paper (scientific journal)  

The sensitive coherent interference of electron waves arising from a specimen is useful for revealing subtle structural information in electron micrographs, which can be important for minimising dose and for rapid imaging. In general, dynamical diffraction is expected due to the useful strong interactions of electrons with matter, which can create phase contrast that violates the requisite Radon projection assumption for tomography. It is for these reasons that incoherent imaging modalities such as high angle annular dark field have been favoured to date in electron tomography of crystalline specimens, to access a monotonic relationship between specimen thickness and micrograph intensity. Here we use a geometric approach to track topological features that are robust to perturbation of the imaging conditions, to enable 3D reconstructions from electron microscope tilt series under imaging conditions that violate the Radon projection assumption, with an emphasis on phase contrast. Invoking a sparsity assumption, we demonstrate that topological features can be reliably tracked in 3D using a differential geometric form of stereoscopy, to circumvent departures from the projection approximation and reduce noise by effecting segmentation of interest points from the outset. We demonstrate this approach on a variety of different specimen and data types, from polyhedral nanoparticles, to steel dislocation networks, cryo-EM cellular structures and 3D diffuse diffraction of a relaxor ferroelectric.

DOI： 10.1016/j.ultramic.2022.113475

Web of Science

Scopus

PubMed

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Language：English   Publisher：The Iron and Steel Institute of Japan  

<p>To quantitatively evaluate the three-dimensional lamellar curvature in pearlitic steel, the crystallographic orientation rotation of ferrite and cementite was analyzed using scanning electron microscopy and electron backscattering diffraction. In the hypereutectoid steel containing 0.92% C, 0.30% Mn, 0.20% Si, and 0.19% Cr, the ferrite–cementite interfaces in some colonies were confirmed to match well with those having frequently observed habit planes with the Pitsch–Petch orientation relationship. It was also confirmed that the ferrite and cementite near the ferrite–cementite interface rotated toward the same orientation to maintain the Pitsch–Petch orientation relationship and the habit plane. Based on the confirmation that the ferrite–cementite interface is well approximated by (010) plane of the adjacent cementite, the lamellae were revealed to have three-dimensional anisotropic curvature.</p>

DOI： 10.2355/isijinternational.isijint-2021-194

Web of Science

Scopus

CiNii Research

Language：Japanese   Publisher：The Japan Institute of Metals and Materials  

DOI： 10.2320/materia.61.84

CiNii Books

CiNii Research

J-GLOBAL

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Other Link： https://www.jstage.jst.go.jp/article/materia/61/2/61_84/_pdf

Language：English  

Language：English  

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Language：English   Publisher：エルゼビア・ジャパン(株)  

ヒアルロン酸の関節内注射後に、壊死性筋膜炎を発症した剖検例について報告した。症例は73歳女性で、肩関節周囲炎と変形性膝関節症による関節痛のため、クリニックで左肩と左膝にヒアルロン酸の関節内注射を受けていた。夫の証言では、帰宅後、PM10時頃はリビングでソファの近くで寝ていたが、翌朝AM10時頃、ソファの下で仰臥位で死んでいた。また、法医解剖では左肩と左膝に水疱と紅斑を伴った注射痕が認められ、左上腕部と左大腿部には筋組織の液化壊死が観察された。さらに、病理組織学検査では、左上腕部と左大腿部に多数の細菌クラスターを伴った重度の横紋筋融解症も認められ、細菌学的検査ではA群レンサ球菌が検出され、血液生化学検査では血中尿素窒素、クレアチニンおよびC反応性タンパク質の濃度上昇も認められた。これらの所見から、死因は劇症型溶血性レンサ球菌感染症(STSS)と診断され、感染経路として、注射が適切に行われておらず、細菌の侵入経路となった可能性が示唆された。

Language：Japanese   Publisher：CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN  

<p>MgB₂ compound is one of the low activation superconducting materials because the half-life time of the MgB₂ phase is much shorter than that of the Nb-based superconductors, such as Nb-Ti and Nb₃Sn. The natural boron powder as the boron source of the in-situ MgB₂ wire and bulk consists of two kinds of stable isotope materials, which are B-10 (¹⁰B:19.78 %) and B-11 (¹¹B: 80.22 %) isotopes. The ¹¹B isotope is a promising raw material for the further improvement of the neutron irradiation effect on the low activation MgB₂ wire. This study focused on the quality effect of the ¹¹B isotope raw powder on the superconducting properties of the ¹¹B isotope-originated MgB₂ (Mg¹¹B2) wire. We found that the nano-order particle size and the higher purification of the ¹¹B isotope raw powder would be efficient in the improvement of the superconducting properties of the low activation Mg¹¹B₂ wire.</p>

DOI： 10.2221/jcsj.57.31

CiNii Books

CiNii Research

J-GLOBAL

researchmap

Other Link： http://id.ndl.go.jp/bib/031955193

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1038/s41427-021-00337-5

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1038/s41598-021-85216-3

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1038/s41598-021-99914-5

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acsanm.1c02615

Language：Others   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.biteb.2021.100765

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acsaelm.1c00364

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3390/nano11061547

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2109/jcersj2.20173

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1103/physrevmaterials.5.014801

Language：Others   Publishing type：Research paper (scientific journal)  

Language：Others   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.cossms.2020.100850

Language：English  

Electron tomography imaging methods with diffraction contrast for materials research
Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) enable the visualization of three-dimensional (3D) microstructures ranging from atomic to micrometer scales using 3D reconstruction techniques based on computed tomography algorithms. This 3D microscopy method is called electron tomography (ET) and has been utilized in the fields of materials science and engineering for more than two decades. Although atomic resolution is one of the current topics in ET research, the development and deployment of intermediate-resolution (non-atomic-resolution) ET imaging methods have garnered considerable attention from researchers. This research trend is probably not irrelevant due to the fact that the spatial resolution and functionality of 3D imaging methods of scanning electron microscopy (SEM) and X-ray microscopy have come to overlap with those of ET. In other words, there may be multiple ways to carry out 3D visualization using different microscopy methods for nanometer-scale objects in materials. From the above standpoint, this review paper aims to (i) describe the current status and issues of intermediate-resolution ET with regard to enhancing the effectiveness of TEM/STEM imaging and (ii) discuss promising applications of state-of-the-art intermediate-resolution ET for materials research with a particular focus on diffraction contrast ET for crystalline microstructures (superlattice domains and dislocations) including a demonstration of in situ dislocation tomography.

DOI： 10.1093/jmicro/dfaa002

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/materia.58.746

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.2320/matertrans.MT-M2019190

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/matertrans.M2019069

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/TASC.2019.2907229

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/1361-6668/ab0eb6

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.intermet.2019.03.005

Language：English   Publishing type：Research paper (scientific journal)  

In-situ straining and electron tomography system: its development and performance

Language：Japanese  

DOI： 10.2320/materia.57.589

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acsphotonics.8b00936

Language：Others   Publishing type：Research paper (other academic)  

DOI： 10.1109/INTMAG.2018.8508412

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.actamat.2018.05.045

Language：English   Publishing type：Research paper (other academic)  

Development of an in-situ straining and time-resolved electron tomography data acquisition system

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jallcom.2018.01.012

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jallcom.2018.01.012

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/matertrans.L-M2018802

Language：Japanese   Publishing type：Research paper (scientific journal)  

Magnetic properties and mechanical properties of high purity Fe-3 mass%Si alloy by cold crucible levitation melting was investigated. The raw material of the alloy made from electrolytic iron and pure silicon with a purity of 99.99 mass% and 99.999 mass% in amount of impurities excluding Fe and Si were suppressed to 90 ppm or less. In the magnetic property, the iron loss of the alloy was reduced to a third of 35H210, a silicon steel sheet of the same Si composition commercially. This reduction shows the effect of high purity. In the magnetic domain observation, the equal behavior as magnetic properties was observed. In mechanical property, it proved that the high purity Fe-3 mass% Si alloy was easy to draw because the elongation of the alloy was higher than the commercially available silicon steel sheet.

DOI： 10.2320/jinstmet.J2018008

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/jinstmet.J2018015

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2207/qjjws.36.26

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.ultramic.2017.07.016

Language：English   Publishing type：Research paper (other academic)  

DOI： 10.1088/1757-899X/219/1/012026

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/1757-899X/196/1/012006

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1093/jmicro/dfw109

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/matertrans.M2016258

Language：English   Publishing type：Research paper (scientific journal)  

In-situ straining and time-resolved electron tomography data acquisition in a transmission electron microscope
This paper reports the preliminary results of a new in-situ three-dimensional (3D) imaging system for observing plastic deformation behavior in a transmission electron microscope (TEM) as a directly relevant development of the recently reported straining-and-tomography holder [Sato K et al (2015) Development of a novel straining holder for transmission electron microscopy compatible with single tilt-axis electron tomography. Microsc. 64: 369-375]. We designed an integrated system using the holder and newly developed straining and image-acquisition software and then developed an experimental procedure for in-situ straining and time-resolved electron tomography (ET) data acquisition. The software for image acquisition and 3D visualization was developed based on the commercially available ET software TEMography(TM) We achieved time-resolved 3D visualization of nanometer-scale plastic deformation behavior in a Pb-Sn alloy sample, thus demonstrating the capability of this system for potential applications in materials science.

DOI： 10.1093/jmicro/dfw109

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.matchar.2016.06.020

Language：English   Publishing type：Research paper (other academic)  

Development of a novel straining holder for TEM compatible with electron tomography

DOI： 10.1002/9783527808465.EMC2016.6262

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.apcatb.2016.03.001

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s12613-016-1306-0

Language：English   Publishing type：Research paper (scientific journal)  

Deformation and dissolution behaviors are important characteristics of soft dispersion particles in steel to improve the deformability of high strength steel sheets by controlling the work hardening/softening and fracture processes associated with particle dispersion strengthening. In this study, the deformation and dissolution behaviors of ϵ-Cu precipitate particles in a ferrite matrix were investigated to understand how relatively soft dispersion particles influence mechanical responses of the steel compared to hard dispersion particles such as alloy carbides. 35 nm diameter nearly spherical ϵ-Cu particles were initially elongated along the rolling direction by cold rolling, and then these were partly dissolved into the ferrite matrix as the equivalent strain increased. The dissolution of the Cu particles was suggested to be caused by a dynamic partitioning of Cu atoms from the precipitates into the matrix by dislocation shearing at the particle tip sharpened by severe cold working. Simultaneously, the contribution of the ϵ-Cu particles to the dispersion strengthening appeared to be decreased with increasing dislocation density in the matrix during cold rolling. The dislocation density and other defects in the ϵ-Cu particles also increased and the particle/matrix interfaces were serrated or became indistinct as deformation progressed. The morphology, internal defects, and interface structure changes of fine dispersion particles and their correlation with mechanical responses of the alloy are discussed in reference to an identically processed, hard particles dispersed Fe-V binary alloy.

DOI： 10.1016/j.actamat.2016.03.018

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.actamat.2016.03.018

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/S1003-6326(16)64285-1

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.7567/APEX.9.065502

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.15282/jmes.10.1.2016.14.0182

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s12613-016-1239-7

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.micron.2015.12.002

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.msea.2015.09.076

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.msea.2015.09.076

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jallcom.2015.09.253

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jallcom.2015.09.253

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2355/isijinternational.ISIJINT-2015-735

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2355/isijinternational.ISIJINT-2016-310

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2355/tetsutohagane.TETSU-2015-086

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1039/c5ra26095g

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1093/jmicro/dfw083

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.fusengdes.2015.05.005

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.actamat.2015.03.007

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/TASC.2014.2382874

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/TASC.2014.2379928

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/TASC.2014.2376193

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.scriptamat.2015.02.001

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.scriptamat.2015.02.001

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/jp509340s

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/14786435.2015.1021400

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.biomaterials.2014.10.025

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.ceramint.2015.01.051

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/jinstmet.J2014063

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/jinstmet.J2015026

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2355/tetsutohagane.101.59

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1093/jmicro/dfv021

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2355/isijinternational.55.623

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1246/cl.150903

Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.phpro.2015.12.090

Language：English   Publishing type：Research paper (scientific journal)  

In this work, we report first-principles investigation of structural stability of all experimentally observed ordered long-period superstructures (LPSs), viz., r-Al₂Ti, h-Al₂Ti, Al₅Ti ₃ along with Al₅Ti₃′, Al ₁₁Ti₇ and Al₃Ti₂ LPSs, which are observed only as short-range ordered clusters at nanoscale level in Al-rich TiAl-based alloys. We adopt a procedure based on space-filling tiling arrangement of ordered Ti₂Al, Ti₃Al, Ti₄Al motifs and their combination along with a symmetry analysis programme to determine the unit cell and the crystallographic information of Al ₅Ti₃′, Al₁₁Ti₇ and Al ₃Ti₂ LPSs in terms of L₁₀ fcc unit cell. First-principles calculations are performed to further refine these crystallographic parameters (Wyckoff positions and lattice parameters) obtained from the above procedure. Moreover, it is found that the family of five LPSs have subgroup-supergroup relationships with γ-TiAl (Sp. gr. P4/mmm) and among themselves. Further, we find the inherent stability of r-Al₂Ti + γ-TiAl and 2Al₅Ti₃ + γ-TiAl phase mixtures at 0 K compared to isomolecular Al₃Ti₂ and Al ₁₁Ti₇ LPSs at their respective concentrations. The calculations of single-crystal elastic constants of Al₅Ti ₃, Al₁₁Ti₇, Al₃Ti₂ and Al₅Ti₃′ LPSs show all these four structures are mechanically stable. We also calculate antiphase boundary (APB) formation energies for two types of APBs, viz., type-A and type-C in ordered Al ₅Ti₃ LPS using the supercell approach. The relaxed APB energies for type-A and type-C APBs are 15.44 and 124.16 mJ/m², respectively.

DOI： 10.1080/14786435.2014.885135

Language：English   Publishing type：Research paper (scientific journal)  

In this work, we report first-principles investigation of structural stability of all experimentally observed ordered long-period superstructures (LPSs), viz., r-Al2Ti, h-Al2Ti, Al5Ti3along with Al5Ti3′, Al11Ti7and Al3Ti2LPSs, which are observed only as short-range ordered clusters at nanoscale level in Al-rich TiAl-based alloys. We adopt a procedure based on space-filling tiling arrangement of ordered Ti2Al, Ti3Al, Ti4Al motifs and their combination along with a symmetry analysis programme to determine the unit cell and the crystallographic information of Al5Ti3′, Al11Ti7and Al3Ti2LPSs in terms of L10fcc unit cell. First-principles calculations are performed to further refine these crystallographic parameters (Wyckoff positions and lattice parameters) obtained from the above procedure. Moreover, it is found that the family of five LPSs have subgroup-supergroup relationships with γ-TiAl (Sp. gr. P4/mmm) and among themselves. Further, we find the inherent stability of r-Al2Ti + γ-TiAl and 2Al5Ti3+ γ-TiAl phase mixtures at 0 K compared to isomolecular Al3Ti2and Al11Ti7LPSs at their respective concentrations. The calculations of single-crystal elastic constants of Al5Ti3, Al11Ti7, Al3Ti2and Al5Ti3′ LPSs show all these four structures are mechanically stable. We also calculate antiphase boundary (APB) formation energies for two types of APBs, viz., type-A and type-C in ordered Al5Ti3LPS using the supercell approach. The relaxed APB energies for type-A and type-C APBs are 15.44 and 124.16 mJ/m2, respectively. © 2014 Taylor and Francis.

DOI： 10.1080/14786435.2014.885135

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.ceramint.2013.10.020

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2355/tetsutohagane.100.688

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/1.4862670

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/1742-6596/507/2/022009

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/matertrans.M2013427

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.ceramint.2013.05.010

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s11595-013-0826-y

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jallcom.2012.04.009

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.msea.2013.04.024

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/S1003-6326(13)62585-6

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.physc.2013.02.011

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/09500839.2013.769068

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.physc.2013.02.011

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/09500839.2013.769068

Language：English   Publishing type：Research paper (other academic)  

DOI： 10.1557/opl.2013.456

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10853-012-6901-5

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/14786435.2012.699691

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10853-012-6901-5

Language：English   Publishing type：Research paper (other academic)  

DOI： 10.4028/www.scientific.net/MSF.747-748.559

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/TASC.2012.2233856

Language：English   Publishing type：Research paper (other academic)  

DOI： 10.1063/1.4794662

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/TASC.2013.2238284

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.phpro.2013.04.054

Language：English   Publishing type：Research paper (other academic)  

DOI： 10.1557/opl.2012.430

Language：English   Publishing type：Research paper (scientific journal)  

Premonitory effects manifest themselves in an ordering transition of the first kind (order) in the form of anomalously high short-range order (SRO) intensity at temperatures marginally above Tc, the critical transition temperature. This intensity located at the superlattice positions of the long-range ordered (LRO) phase is often attributed to the formation of ‘heterophase fluctuations’ resembling clusters of the LRO phase. Monte Carlo simulations in a hypothetical system showing FCC-to-L12ordering transition have been carried out here to shed some light on this phenomenon and to look into the atomic configurations that make up these fluctuations. 92. © 1997, Taylor & Francis Group, LLC. All rights reserved.

DOI： 10.1080/14786435.2012.713136

Language：Japanese  

Language：Others   Publishing type：Research paper (scientific journal)  

DOI： 10.2355/tetsutohagane.98.117

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1038/am.2012.3

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1038/am.2012.3

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.phpro.2012.06.119

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2355/tetsutohagane.98.117

Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (scientific journal)  

Premonitory effects manifest themselves in an ordering transition of the first kind (order) in the form of anomalously high short-range order (SRO) intensity at temperatures marginally above Tc, the critical transition temperature. This intensity located at the superlattice positions of the long-range ordered (LRO) phase is often attributed to the formation of ‘heterophase fluctuations’ resembling clusters of the LRO phase. Monte Carlo simulations in a hypothetical system showing FCC-to-L1₂ ordering transition have been carried out here to shed some light on this phenomenon and to look into the atomic configurations that make up these fluctuations. 92.

DOI： 10.1080/14786435.2012.713136

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1017/S143192761101213X

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1017/S143192761101213X

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/matertrans.M2011143

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.physc.2011.05.143

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/matertrans.M2011175

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.physc.2011.05.143

Language：English  

DOI： 10.1063/1.4730732

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/14786435.2011.563761

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DOI： 10.1016/j.ultramic.2011.03.021

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DOI： 10.1016/j.ultramic.2011.03.021

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DOI： 10.2320/matertrans.M2010405

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DOI： 10.1109/TASC.2010.2091097

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DOI： 10.1016/j.actamat.2011.01.031

Language：English  

DOI： 10.1002/9781118062142.ch70

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.msea.2010.09.058

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DOI： 10.1080/14786435.2010.510453

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DOI： 10.1007/s12666-010-0125-7

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DOI： 10.1007/s12666-010-0125-7

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DOI： 10.1143/JJAP.49.090208

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DOI： 10.1016/j.tsf.2010.06.023

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.msea.2010.07.004

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.scriptamat.2010.01.002

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.ijfatigue.2009.06.006

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.actamat.2009.10.027

Language：English   Publishing type：Research paper (scientific journal)  

This paper reports the mechanical property and crack propagation behavior of thin ceramics. A method to evaluate the stress intensity factor, K _I, of thin ceramics was proposed. Dependence of K_I values on the average grain size, d, of thin α-alumina were measured by the method. K_I values of thin α-alumina decreased with increasing d values from 4.3 μm to 15.2 μm, while the KI values were almost constant for 15.2 μm ≤d≤63.0 μm. The trend of K_I values agreed with the dependence of fracture toughness, K_c, of bulk α-alumina. The thin α-alumina specimens after crack propagation were investigated by scanning electron microscopic electron back-scattered diffraction (SEM/EBSD) analysis. Branched cracks were hardly observed, regardless of grain size. The result indicates that the toughing mechanism do not occur in the thin α-alumina. Dependence of the transgranular fracture rate, F, and the crack deflection rate, D, on d were measured from the orientation distribution maps. However, the F values and the D values were independent of d and approximately constant. The F values and D values depend on d in bulk α-alumina. It indicates that the crack propagation behavior is varied by thinning α-alumina.

DOI： 10.2320/jinstmet.74.24

Language：English   Publishing type：Research paper (other academic)  

DOI： 10.4028/www.scientific.net/AMR.89-91.473

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/materia.48.610

Language：Japanese  

We report relationships between the superconducting properties, microstructure and fabrication conditions in high-density MgB₂ bulks fabricated using a premix-powder-in-closed-tube (PICT) method. The microstructure of the MgB₂ bulks depends on the crystallinity of the initial B powders; use of crystalline B powders reduces the amount of MgB₂ and increases re-sidual B and MgO. The heat treatment condition influences the grain sizes of MgB₂ as well as the distribution and grain sizes of MgO. A lower temperature and a shorter duration of heat treatment tend to form fine grains of MgB₂ and uniform dispersion of fine MgO particles. These microstructural variations influence the distribution of effective flux pinning centers such as grain boundaries and fine MgO particles. Different types of critical current density behavior as a function of magnetic field were meas-ured.

DOI： 10.2221/jcsj.44.613

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.physc.2009.05.059

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/TASC.2009.2018527

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/jinstmet.73.373

Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/matertrans.E2008002

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.scriptamat.2008.06.042

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.scriptamat.2008.06.042

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/matertrans.MAW200828

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/matertrans.MAW200828

Language：English   Publishing type：Research paper (other academic)  

Electrical and Stractural Evaluations of Ultrathin SiGe-and Ge-on-insulator Fabricated Using Ge Condensation by Dry Oxidation

DOI： 10.7567/ssdm.2008.p-3-18

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s11661-007-9397-x

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s11661-007-9397-x

Language：English   Publishing type：Research paper (scientific journal)  

A study was conducted to perform 3D microstructural analysis based on electron tomography. The study also attempted to investigate a unique domain structure in a Ni-Al-Ti alloy. A two-phase microstructure,composed of L1 ₂-ordered γ domains with cuboidal shape and an A1-disordered γ matrix exhibited secondary phase separation during aging precipitation of fine γ in each domain. A variety of precipitation behaviors and microstructural evolutions were observed in the second stage of phase separation, depending on on the alloy composition. The study also demonstrated tomographic DFTEM and EFTEM observations, to clarify the 3D morphology of the γ precipitates and compositional distribution in the phase-separated microstructure.

DOI： 10.1002/adma.200702461

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/adma.200702461

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/1742-6596/97/1/012277

Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/1.2972114

Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/0953-2048/20/12/023

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/materia.46.785

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jcrysgro.2006.10.188

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/0953-2048/19/2/002

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1088/0953-2048/19/2/002

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1093/jmicro/dfl001

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1093/jmicro/dfl001

Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (other academic)  

DOI： 10.1109/EPTC.2006.342749

Language：English   Publishing type：Research paper (scientific journal)  

A transmission electron microscopy (TEM) study has been carried out on an MgB₂/α-Al₂O₃ film that exhibits the typical property of critical current density (J_c) under magnetic fields. The MgB₂ layer of 300 nm in thickness was grown on a (001)α-Al₂O₃ substrate using an in situ electron beam evaporation method. J_c of the film takes significantly high values when the applied magnetic field is perpendicular to the film surface. The MgB₂ layer consists of fine columnar MgB₂ crystals 20-30 nm in size. The columnar MgB₂ crystals grow almost perpendicular to the substrate surface and have no crystallographic orientation relationship with the α-Al₂O₃ substrate because of an amorphous layer formed first on the substrate. A high density of columnar grain boundaries within the MgB₂ layer may be effective for the enhancement of the flux-pinning under the perpendicular magnetic field.

DOI： 10.1088/0953-2048/18/10/005

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jpowsour.2005.02.028

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1093/jmicro/dfi060

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/TASC.2005.848834

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/TASC.2005.848866

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10853-005-1982-z

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/09500830500157462

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/09500830500153776

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1017/S1431927605050026

Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1093/jmicro/dfh049

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.physc.2004.01.168

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/1.1805195

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1093/jmicro/53.1.1

Language：English  

Formation of long-period superstructures in TiAl single crystal with composition-gradient

Language：English  

Anti-phase boundary structure in Al5Ti3 long-period ordered TiAl alloys

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

The atomic arrangements of short-range order (SRO) in two Al-rich γ-TiAl alloys with 62.5 and 60.0 at.% Al respectively have been investigated by high-resolution transmission electron microscopy with image processing. For both alloys, SRO structures are formed in Ti-rich (002) layers of the Ll₀ ordered γTiAl matrix, in the course of the phase transformation from the Al₅Ti₃ long-period superstructure phase at lower temperatures to the h-Al₂Ti phase at higher temperatures. The SRO structures are composed of three types of ordered cluster: Ti₄Al type (square shaped), Ti₃Al type (fat rhombus shaped) and Ti₂Al type (lean rhombus shaped). The ordered clusters form local microdomains of the Al₅Ti₃ and Al₃Ti₂ superstructures in addition to the Al₅Ti₃ and h-Al₂Ti superstructures, by different methods of tiling the ordered clusters. Such ordered clusters or microdomains tend to be in contact with each other through common (310) boundaries. This results in peculiar diffuse streaks in diffraction connecting intensity maxima arising from the long-period superstructures.

DOI： 10.1080/09500830210137425

Language：English   Publishing type：Research paper (scientific journal)  

Short range order in Al-rich g-TiAl of Ti-62.5 and 60.0 at.%Al alloys studied by HRTEM with image processing
The atomic arrangements of short-range order (SRO) in two Al-rich gamma-TiAl alloys with 62.5 and 60.0 at.% Al respectively have been investigated by high-resolution transmission electron microscopy with image processing. For both alloys, SRO structures are formed in Ti-rich (002) layers of the L1(0) ordered gamma-TiAl matrix, in the course of the phase transformation from the Al5Ti3 long-period superstructure phase at lower temperatures to the h-Al2Ti phase at higher temperatures. The SRO structures are composed of three types of ordered cluster: Ti4Al type (square shaped), Ti3Al type (fat rhombus shaped) and Ti2Al type (lean rhombus shaped). The ordered clusters form local microdomains of the Al5Ti3&#039; and Al3Ti2 superstructures in addition to the Al5Ti3 and h-Al2Ti superstructures, by different methods of tiling the ordered clusters. Such ordered clusters or microdomains tend to be in contact with each other through common {310) boundaries. This results in peculiar diffuse streaks in diffraction connecting intensity maxima arising from the long-period superstructures.<br />

Language：Japanese  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/S0921-5093(00)01872-4

Language：English   Publishing type：Research paper (other academic)  

Nanostructure Formation by Short Range Ordering of Al Atoms in Off-stoichiometric g-TiAl

Language：Japanese  

Partially ordered Ni₄Mo alloys were observed for the first time at an atomic resolution with high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM). The Mo atomic columns in the D1_a ordered structure were clearly visualized as bright square dots in the HAADF-STEM image. It was found that the ordered regions were observed with a high contrast in the defocus condition a little overfocused from the Scherzer defocus (&Delta;f=sqrtC_S&middot;&lambda;) which is the condition for the smallest electron probe in STEM. The phenomenon was interpreted successfully by using the approximate imaging theory for HAADF-STEM proposed by Jesson et al. Using the present experimental and simulation results, an approximate imaging theory for visualizing short range ordered state in binary alloys, such as the Ni₄Mo alloys, is proposed.

DOI： 10.2320/jinstmet1952.65.5_414

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/jinstmet1952.65.5_414

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1361/105497101770332938

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/S0968-4328(99)00134-1

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/S1359-6454(98)00180-3

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/matertrans1989.39.914

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/S1359-6454(97)00314-5

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/matertrans1989.39.914

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2320/matertrans1989.39.133

Language：English   Publishing type：Research paper (scientific journal)  

The Monte Carlo method of simulation was employed in the study of time-evolution of atomic long-range ordering with k* = 1/2 1/2 1/2 in an fcc Ising-model system with first- and second-neighbor pairwise interactions V(1) and V(2). The results should refer to the ordering behavior of carbon atoms and vacancies in metalloid-deficient transition-metal monocarbides, such as TiC_1-x and NbC_1-x. Fourier power spectra of the obtained atom-configuration involve diffuse streaks in the early stage of the ordering process, and then exhibit sharp spots at k* = 1/2 1/2 1/2 and its equivalent positions in the late stage. When V(1) has a tendency to create unlike-atom pairs in a similar way to V(2), the spectra in the early stage resemble diffraction patterns of TiC_1-x and NbC_1-x with short-range order. Warren-Cowley parameters α's for atomic pair-correlations increase monotonically with time in even-order coordination shells, suggesting continuous evolution of the 1/2 1/2 1/2-type ordering. In contrast, the values of α for odd-order coordination shells first get enhanced with time and then decrease after reaching a peak. The behavior of odd-order α's is explained in terms of the destructive interference (or frustration) between interactions V(1) and V(2). Two different ordered structures of CuPt (R3m) and cubic (Fd3m) types, which are degenerate in the internal energy, simultaneously appear and their ordered domains grow with time.

Event date： 2023.12

Language：Japanese  

Venue：福岡   Country：Japan  

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Event date： 2023.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2023.11

Language：Japanese  

Venue：東京   Country：Japan  

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Event date： 2023.9

Language：English   Presentation type：Oral presentation (general)  

Country：Korea, Republic of  

Event date： 2023.9

Language：English   Presentation type：Oral presentation (general)  

Country：Korea, Republic of  

Event date： 2023.9

Language：English   Presentation type：Oral presentation (general)  

Country：Korea, Republic of  

Event date： 2023.9

Language：English  

Venue：Busan   Country：Korea, Republic of  

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Event date： 2023.9

Language：English  

Venue：Busan   Country：Korea, Republic of  

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Event date： 2023.9

Language：English  

Venue：Busan   Country：Korea, Republic of  

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Event date： 2023.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Fukuoka   Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2023.9

Language：English  

Venue：Fukuoka   Country：Japan  

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Event date： 2023.9

Language：English  

Venue：Fukuoka   Country：Japan  

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Event date： 2023.9

Language：English  

Venue：Fukuoka   Country：Japan  

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Event date： 2023.9

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Venue：Fukuoka   Country：Japan  

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Event date： 2023.9

Language：English  

Venue：Fukuoka   Country：Japan  

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Event date： 2023.9

Language：English  

Venue：Fukuoka   Country：Japan  

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Event date： 2023.9

Language：English  

Venue：Fukuoka   Country：Japan  

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Event date： 2023.9

Language：English  

Venue：Fukuoka   Country：Japan  

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Event date： 2023.9

Language：English  

Venue：Fukuoka   Country：Japan  

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Event date： 2023.9

Language：English  

Venue：Fukuoka   Country：Japan  

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Event date： 2023.9

Language：English  

Venue：Fukuoka   Country：Japan  

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Event date： 2023.9

Language：English  

Venue：Fukuoka   Country：Japan  

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Event date： 2023.7

Language：English   Presentation type：Oral presentation (general)  

Country：Korea, Republic of  

Event date： 2023.7

Language：English  

Venue：KINTEX   Country：Korea, Republic of  

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Event date： 2023.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：島根   Country：Japan  

Event date： 2023.6

Language：Japanese  

Venue：島根   Country：Japan  

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Event date： 2023.6

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2023.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：熊本   Country：Japan  

Event date： 2023.6

Language：English  

Venue：熊本   Country：Japan  

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Event date： 2023.6

Language：Japanese  

Venue：熊本   Country：Japan  

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Event date： 2023.3

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2023.3

Language：English  

Venue：熊本   Country：Japan  

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Event date： 2021.6

Language：English   Presentation type：Oral presentation (invited, special)  

Country：Japan  

Event date： 2021.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Web   Country：Japan  

Event date： 2021.6

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2021.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Web   Country：Japan  

Event date： 2020.12

Language：English   Presentation type：Oral presentation (general)  

Country：India  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Web   Country：United States  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Web   Country：United States  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Web   Country：United States  

Event date： 2020.10

Language：English   Presentation type：Oral presentation (general)  

Country：China  

Event date： 2020.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Web   Country：Japan  

Event date： 2020.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Web   Country：Japan  

Event date： 2020.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Web   Country：Japan  

Event date： 2020.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Web   Country：Japan  

Event date： 2020.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Web   Country：Japan  

Event date： 2020.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Web   Country：Japan  

Event date： 2020.2

Language：English   Presentation type：Oral presentation (general)  

Country：India  

Event date： 2020.1

Language：English   Presentation type：Oral presentation (general)  

Country：China  

Event date： 2019.12

Language：Japanese   Presentation type：Oral presentation (general)  

Country：China  

Event date： 2019.11

Language：English   Presentation type：Oral presentation (general)  

Country：China  

Event date： 2019.11

Language：English   Presentation type：Oral presentation (general)  

Country：China  

Event date： 2019.9

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2019.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岐阜大学   Country：Japan  

Event date： 2019.8 - 2019.6

Language：English   Presentation type：Oral presentation (general)  

Country：China  

Event date： 2019.8 - 2019.6

Language：English   Presentation type：Oral presentation (general)  

Country：China  

Event date： 2019.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：名古屋市   Country：Japan  

Event date： 2019.6

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2019.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：熊本市   Country：Japan  

Event date： 2019.5

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2019.3

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2018.12