198 research outputs found
Transformation super plasticity deformation of reduced activation ferritic/martensitic steel
No full text0000-0001-9016-2318Reduced Activation Ferritic/Martensitic (RAFM) steel is a promising candidate for the blanket structural materials of fusion reactors. One of the key issues in the use of RAFM for the blanket is its low workability. As a solution of this issue, innovative processing technology based on the transformation super plasticity (TSP) was proposed. In general, TSP is known as high temperature creep deformation which is induced by phase transformation. In this study, tensile tests under constant load were carried out with cyclic temperature variation for a RAFM steel to investigate the effect of cyclic temperature variations on elongation. The result of the tensile test under constant load for the RAFM steel with cyclic temperature variations exhibited a macro-elongation to 172%. The results of the tensile tests with varying loads showed the possibility of reducing the necessary time and enhancing the controllability for the formation of RAFM steel products using TSP.journal articl
Moderation of Negative Oxygen Effects by Small Yttrium Addition to Low Activation Vanadium Alloys
No full text0000-0001-6564-8922In order to improve irradiation embrittlement of vanadium alloys for fusion reactors, yttrium (Y) has been added reducing the interstitial oxygen impurity. However Y addition can also degrade high-temperature strength, because Y could scavenge oxygen in solid solution, which is a strong hardening agent in vanadium alloys. In this study, the effect of Y addition and oxygen level on the mechanical properties was investigated from the view points of both the high-temperature strength and low temperature ductility. Y addition was suggested to moderate the hardening and embrittlement induced by oxygen impurity sustaining the high-temperature strength within an acceptable level.journal articl
Adelencyrtus odonaspidis Fullaway 1913
No full textAdelencyrtus odonaspidis Fullaway, 1913 Comments. The Japanese record is based on BURKS (1958), but this author did not state which material was examined or where the information originated.Published as part of Japoshvili, George, Higashiura, Yoshimitsu & Kamitani, Satoshi, 2016, A review of Japanese Encyrtidae (Hymenoptera), with descriptions of new species, new records and comments on the types described by Japanese authors, pp. 345-401 in Acta Entomologica Musei Nationalis Pragae 56 (1) on page 395, DOI: 10.5281/zenodo.530683
Brass-texture induced grain structure evolution in room temperature rolled ODS copper
No full textCurrently, advanced ODS copper alloy is under study as a potential fusion material providing good mechanical properties. In this work, in order to develop a high performance ODS copper containing 0.5 wt% Y2O3 oxide particles, the effect of room temperature rolling and subsequent annealing on the grain structure evolution, texture development and tensile properties are studied using EBSD, TEM and tensile tests. Microstructure evolution studies show the grain structure coarsens by enhancing the Brass texture during increase of rolling reduction and a unique single crystal-like brass-texture deformed structure is achieved after 80% rolling reduction. We found the deformation mechanism of partial slip by a/2 211 dislocations facilitated by the pinning of a/2 101 perfect dislocations through fine oxide particles is responsible for formation of Brass texture during room temperature rolling. Furthermore, the recrystallization of ODS copper retards to high temperature of similar to 700 degrees C and shows a fine-grained microstructure with different orientations of Goss, Brass, S and Copper. Evaluation of microstructure-mechanical properties of the recrystallized samples expresses that the bimodal grain size distribution at 800 degrees C for 30 min offers a good tensile strength-ductility (UTS: 491 MPa, el(t): 19%) at ambient temperature
Neutron irradiation effect on superconductivity of Nb3Sn wire - 50 Hz data acquisition system -
No full textA research facility for neutron irradiation effect on superconducting materials has been installed at Oarai center in Tohoku University in 2012 as part of a post irradiation experiment. It consists of a 15.5 T superconducting magnet, a variable temperature insert and a data acquisition and control system. Since the sample holder is cooled by thermal conduction with G-M refrigeration, there is a small temperature difference between positive and negative electrodes and the sample temperature rises during the critical current test due to joule heating. To evaluate the temperature rise precisely, a new data acquisition system with a sampling rate of 50 Hz has been installed. By measuring the temperatures of both electrodes and the voltage at the center of the sample, the temperature of the sample was estimated and the measured critical current (IC) was converted to the current at 4.2 K with a critical surface equation. The comparison of IC at different conditions including neutron irradiated samples was implemented and the neutron irradiation effect on superconductivity of Nb3Sn wire is discussed based on the 4.2 K superconductivity. This paper will describe the outline of the new data acquisition system and some results of neutron irradiated Nb3Sn wires
Improving the Quality of Web Surveys: The Checklist for Reporting Results of Internet E-Surveys (CHERRIES) Japanese Version
No full textCHERRIES 日本語版 (原著 [Original article] = Eysenbach G. Improving the Quality of Web Surveys: The Checklist for Reporting Results of Internet E-Surveys (CHERRIES). J Med Internet Res 2004;6(3):e34 DOI: 10.2196/jmir.6.3.e34. PMID: 15471760. PMCID: PMC1550605; Eysenbach G. Correction: Improving the Quality of Web Surveys: the Checklist for Reporting Results of Internet E-Surveys (CHERRIES). J Med Internet Res 2012;14(1):e8. DOI: 10.2196/jmir.2042. PMID: 22223031. PMCID: 4220447)[Author = 原著者] Gunther Eysenbach, [Translators = 訳者] Yoshimitsu Takahashi (高橋由光), Takeo Nakayama (中山健夫)著者向けのe調査推奨チェックリスト「CHERRIES」は、e調査 [e-survey] の方法論を完全に記載できるように、メディカル・インターネット・リサーチ誌 [Journal of Medical Internet Research (JMIR)] によって作られた。これは、医学文献報告の質を確保するために作成されたCONSORT 声明(ランダム化試験向け)や、QUOROM声明(システマチックレビュー向け）のような、推奨用チェックリストに準じている。CHERRIES 声明に則ったウェブベース調査の論文によって、読者は標本集団の(自己)選択 [sample (self-)selection] に関してより適切に理解することができる。そして、「代表性のある」標本集団 [representative sample] とは異なる意義のある新たな可能性に気づくことができるだろう。著者がこのチェックリストを守ることで、ウェブベース調査に関する報告の有用性が増すことが期待される
Microstructure of the New Route Wire Fabrication of V<sub>3</sub>Ga Compound Superconducting Wire Using High Ga Content Cu-Ga/V Precursor Composite Material
No full textOur co-worker, Hishinuma et. al. has established a new route Powder-In-Tube (PIT) process using a high Ga content Cu-Ga compound in order to improve the superconducting property of the V3Ga compound wire. In this study, we investigated microstructure of this high Ga content Cu-Ga/V composite superconducting wire. The different contrasts of matrix, V-Ga phase and Cu-Ga core were observed by SEM observation in cross section of 19 multifilamentary wire. And V-Ga phase was confirmed by SEM mapping. The area fraction of V-Ga phase increased when Ga content increased from 30% to 50%. Thin film sample with V-Ga phase for TEM was fabricated by FIB and observed by TEM in detail. Selected area diffraction pattern was obtained for V matrix, V-Ga phase and Cu-Ga core. The ratio of V to Ga for V-Ga phase was probably V3Ga according to the EDS result. There was a linear interface between V matrix and V-Ga phase, while the interface between Cu-Ga core and V-Ga phase was not linear. On the other hand, there were some granular grains observed in V-Ga phase wear Cu-Ga core.</jats:p
The Effect of Thermal History on Microstructure of Er2O3 Coating Layer Prepared by MOCVD Process
No full textEr2O3 is a high potential candidate material for tritium permeation barrier and electrical insulator coating for advanced breeding blanket systems with liquid metal or molten-salt types. Recently, Hishinuma et al. reported to form homogeneous Er2O3 coating layer on the inner surface of metal pipe using Metal Organic Chemical Vapor Deposition (MOCVD) process. In this study, the influence of thermal history on microstructure of Er2O3 coating layer on stainless steel 316 (SUS 316) substrate by MOCVD process was investigated using SEM, TEM and XRD. The ring and net shape selected-area electron diffraction (SAED) patterns of Er2O3 coating were obtained each SUS substrates, revealed that homogeneous Er2O3 coating had been formed on SUS substrate diffraction patterns. Close inspection of SEM images of the surface on the Er2O3 coating before and after thermal cycling up to 700 °C in argon atmosphere, it is confirmed that the Er2O3 particles were refined by thermal history. The column-like Er2O3 grains were promoted to change to granular structure by thermal history. From the cross-sectional plane of TEM observations, the formation of interlayer between Er2O3 coating and SUS substrate was also confirmed
The Effect of Thermal History on Microstructure of Er<sub>2</sub>O<sub>3 </sub>Coating Layer Prepared by MOCVD Process
No full textEr2O3 is a high potential candidate material for tritium permeation barrier and electrical insulator coating for advanced breeding blanket systems with liquid metal or molten-salt types. Recently, Hishinuma et al. reported to form homogeneous Er2O3 coating layer on the inner surface of metal pipe using Metal Organic Chemical Vapor Deposition (MOCVD) process. In this study, the influence of thermal history on microstructure of Er2O3 coating layer on stainless steel 316 (SUS 316) substrate by MOCVD process was investigated using SEM, TEM and XRD. The ring and net shape selected-area electron diffraction (SAED) patterns of Er2O3 coating were obtained each SUS substrates, revealed that homogeneous Er2O3 coating had been formed on SUS substrate diffraction patterns. Close inspection of SEM images of the surface on the Er2O3 coating before and after thermal cycling up to 700 °C in argon atmosphere, it is confirmed that the Er2O3 particles were refined by thermal history. The column-like Er2O3 grains were promoted to change to granular structure by thermal history. From the cross-sectional plane of TEM observations, the formation of interlayer between Er2O3 coating and SUS substrate was also confirmed.journal articl
Effect of atmospheric control during MA-HIP process on mechanical properties of oxide dispersion-strengthened Cu alloy
No full text0000-0001-9016-2318In this study, mechanical properties of Dispersion Strengthened (DS)-Cu-Al (aluminum) and Zr (zirconium) alloys, which were fabricated by an MA-HIP method, were investigated for application to the heat sink materials of fusion reactors. The effect of air exposure before the HIP process was studied using a NIFS-Sealing Device. Cu–Al specimen with air exposure before HIP was broken during wire-electrical discharge formation. Cu–Al specimen without air exposure exhibited high fracture strength, but without yielding. Cu–Zr specimen, both with and without the exposure, yielded and exhibits elongation. An increase in yield and tensile strength by approximately 61% and 45%, respectively, were obtained for Cu–Zr specimen by avoiding air exposure. The results showed that Cu–Zr specimen is less susceptible to the atmosphere of the MA-HIP process than Cu–Al.journal articl
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