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超微細結晶粒を持つAl-Mg-Sc合金の繰り返し変形における転位組織図の構築
Get PDF本研究ではAl-Mg-Sc合金を用いて,第二相析出物を含む超微細結晶粒材料の疲労挙動と転位組織の関係を明らかにしようとした研究であり,平成16年度はAl-1mass%Mg-0.27mass%Sc合金のECAP後の試料における,焼鈍に伴う機械的特性の変化特に高サイクル疲労挙動について調査を行った.
1.ECAP後の試料(ECAP材)は降伏応力・引張強さ(303,333MPa)は高いが,降伏後直ちにネッキングを生じ応力低下を引き起こし早期破断(破断伸び:8.5%)に至る.
2.ECAP後試料に350℃に置いて15分,1時間の焼鈍を施した試料では,降伏応力と引張強さは低下するが,均一伸び・破断伸びは改善した.
3.降伏応力の30%〜60%の一定応力振幅下での高サイクル疲労寿命はECAP材が一番短く,焼鈍を施すことで2倍以上の疲労寿命の改善が見られた.
4.ECAP材では繰り返し変形中に動的回復・再結晶により結晶粒径が200nmから1μm以上へと粗大化している箇所が観察され,このような箇所で変形の局在化が起こるため疲労寿命が短くなると理解できる.
5.一方,両焼鈍材では結晶粒内・粒界に析出したAl_3Sc析出物により,ECAP材に見られたような動的回復・再結晶は抑止される.その結果,変形の局在化は生じず変形は均一となり,疲労寿命が改善する.
また,ECAP加工を施していない通常の材料に時効熱処理を施し,ECAP材と同じ程度の析出物サイズを持つ試料を作成し同様な試験を行い,Al_3Sc析出粒子の分散状況の変化に伴う,繰り返し変形挙動と内部転位組織の変化の調査も行った.その結果,Al_3Sc析出粒子が小さいとき(4〜5nm程度)は運動転位による粒子のせん断が起こり,疲労軟化が起こること,一方大きいときには変形は均一となり,疲労軟化現象が生じないことを明らかにした.研究課題/領域番号:15760489, 研究期間(年度):2003 – 2004出典：「超微細結晶粒を持つAl-Mg-Sc合金の繰り返し変形における転位組織図の構築」研究成果報告書 課題番号15760489
（KAKEN：科学研究費助成事業データベース（国立情報学研究所））
（https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-15760489/)を加工して作成金沢大学理工研究域research repor
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Concurrently strengthened severely deformed metallic materials by ultra-fine grained and precipitation hardenings
Get PDF各種析出強化型銅合金に，高圧ねじり（HPT）加工を施し，加工硬化量及び，時効硬化挙動に付いて系統的な調査を行った．HPT加工による到達最高硬さ，及び続く時効強化挙動に及ぼす加工温度の影響を明らかにした．さらに，HPT加工後の自然時効が，続く人工時効に及ぼす影響についても明らかにした．以上の結果は，巨大ひずみ加工による結晶粒超微細化と析出強化の重畳の実現へ新たな知見を与えるものである．The microstructure and aging behavior in Cu based age-hard enable alloys processed by high-pressure torsion (HPT) were systematically investigated. The effects of processing temperature on attainable maximum hardness by HPT and age-hardening behavior of the alloys after HPT were clearly explained. Moreover, the influence of natural aging on the artificial aging behavior of Cu-Be and Cu-T alloys systems were discussed. The obtained results in this study shed light on strengthening of the metallic materials by grain-refinement strengthening and precipitation hardening simultaneously.研究課題/領域番号:25420775, 研究期間(年度):2013-04-01 - 2016-03-31出典：研究課題「巨大ひずみ加工による結晶粒超微細化強化と析出強化の同時利用の実現」課題番号:25420775
（KAKEN：科学研究費助成事業データベース（国立情報学研究所））
（https://kaken.nii.ac.jp/report/KAKENHI-PROJECT-25420775/25420775seika/）を加工して作成金沢大学理工研究域機械工学系research repor
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Enhancement of fatigue properties of Al-Mg and Al-Mg-Si alloys at elevated temperatures by addition of small amount of Scandium
Get PDFScを添加したAl-Mg合金及びAl-Mg-Si合金を作製し,高温における疲労挙動の調査を行った.その結果,Al-Mg合金においては,Al_3Sc粒子サイズが小さい場合には,運動転位による粒子のせん断が生じ疲労軟化を示し,粒子サイズが大きな場合には変形は均一となり疲労軟化は生じなかった.Al-Mg-Si合金においては,Scを添加する事で,・'-Mg_2Si析出物に加えてAl_3Sc粒子が析出し,このAl_3Sc粒子の存在により,変形の局在化を抑制し,疲労寿命が大きく改善する事を示した.The effects of small amount of Sc addition on the fatigue properties of Al-Mg and Al-Mg-Si alloys at elevated temperatures have been examined. Cyclic softening after initial hardening is found in the Al-Mg alloys with small Al_3Sc particles, but no cyclic softening takes place in the alloys with larger particles. The cyclic softening is explained by a loss of particle strengthening through particle shearing within strongly strained slip bands. The larger Al_3Sc particles have a stronger retardation effect on the formation of fatigue-induced stable dislocation structure than small particles even at a high temperature. After peak-aging treatments, the Al-Mg-Si alloys has fine lath-shaped β' precipitates. In the Sc-containing Al-Mg-Si alloy, spherical Al_3Sc precipitates of about 11 nm in diameter are co-existed. The Al-Mg-Si alloy with Sc exhibits cyclic hardening to saturation, while the alloy without Sc shows clear cyclic softening after initial hardening. In the Sc-bearing Al-Mg-Si alloy, owing to the existence of non-shearable Al_3Sc precipitates, dislocations were uniformly distributed, resulting in the improvement of fatigue life.出典：研究課題「Sc含有Al-Mg合金及びAl-Mg-Si合金の高温疲労特性の評価と改善」課題番号19760063
（KAKEN：科学研究費助成事業データベース（国立情報学研究所））
（https://kaken.nii.ac.jp/report/KAKENHI-PROJECT-19760063/19760063seika/）を加工して作成金沢大学理工研究域機械工学系research repor
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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