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X-Ray Stress Measurement for Rolled Magnesium Alloy AZ61 Made by Twin-Roll Casting 双辊铸造AZ61镁合金轧制的x射线应力测量
journal of the Japan Society for Testing Materials Pub Date : 2014-01-01 DOI: 10.2472/JSMS.63.539
K. Yatsushiro, D. Suzuki, M. Sano, Teruo Ishiguro, Yukari Mitsui, C. Sakamoto, Tomomi Ito, H. Katagiri
{"title":"X-Ray Stress Measurement for Rolled Magnesium Alloy AZ61 Made by Twin-Roll Casting","authors":"K. Yatsushiro, D. Suzuki, M. Sano, Teruo Ishiguro, Yukari Mitsui, C. Sakamoto, Tomomi Ito, H. Katagiri","doi":"10.2472/JSMS.63.539","DOIUrl":"https://doi.org/10.2472/JSMS.63.539","url":null,"abstract":"For the application to the structure part of the magnesium alloy, material evaluations such as mechanical strength, fatigue property and property of stress corrosion cracking are necessary. Therefore, the X-ray stress measurement that is Non-destructive inspection is effective technique. However, there are few reports that described X-rays stress measurement about magnesium alloy. The report considered about X-ray elastic constant and stress constant in detail is not found. In this report, X-ray elastic and stress constants of rolled AZ61 magnesium alloy were measured. As result, by removing surface layer that has anelastic behavior and considering texture of specimen, X-ray elastic and stress constants can be measured. The X-ray elastic constants of AZ61 magnesium alloy in as received specimens were 41.2 GPa by using 101 _ 4 diffraction and 39.9 GPa by using 101 _ 5 diffraction.","PeriodicalId":17366,"journal":{"name":"journal of the Japan Society for Testing Materials","volume":"93 1","pages":"539-544"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83337169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Dry Fabric Forming Analysis Considering the Influence of Tensions on In-plane Shear Behavior 考虑张力对面内剪切性能影响的干织物成形分析
journal of the Japan Society for Testing Materials Pub Date : 2014-01-01 DOI: 10.2472/JSMS.63.380
Masato Nishii, T. Hirashima, T. Kurashiki
{"title":"Dry Fabric Forming Analysis Considering the Influence of Tensions on In-plane Shear Behavior","authors":"Masato Nishii, T. Hirashima, T. Kurashiki","doi":"10.2472/JSMS.63.380","DOIUrl":"https://doi.org/10.2472/JSMS.63.380","url":null,"abstract":"In this study, we propose a FE model for dry fabric forming simulation that can express the tension dependent shear behavior in order to predict the wrinkles, one of the major forming defects. Automakers are gradually using more carbon fiber reinforced plastic (CFRP) in mass production cars, because the development of resin transfer molding (RTM) have reduced its cycle time to less than 10 minutes. Finite element analysis (FEA) is essential to the vehicle design process, so numerical simulation of CFRP is strongly desired today. Forming simulation is especially important, because the performance of the final composite part strongly depends on changes in fiber orientation during the preforming. Moreover wrinkle is one of the major defects in preforming. RTM usually involves fabric reinforcement. During forming of fabric, large in-plane shear deformations typically occur. The reason for this is that the shear resistance is very low at the initial stage, because the deformation is governed by yarn contact friction at the cross-sections. Accurately expressing the in-plane shear behavior of fabric is very important for accurate forming simulation. In most simulation models the shear resistance of fabric is assumed to be independent from the tension along the yarn. However, meso-model predictions of the picture frame and bias-extension tests suggest this to be an invalid assumption. In this study, a micromechanical model that introduces the stress component due to the yarn rotational friction is adapted to the dry fabric forming simulation. In other words, this can express the shear behavior that depends on the tensions in the yarns. The results using this micromechanical model are in good agreement with the meso-model results in the various boundary conditions.","PeriodicalId":17366,"journal":{"name":"journal of the Japan Society for Testing Materials","volume":"8 1","pages":"380-385"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87056630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 10
Prediction of Liquefaction and Countermeasure due to Groundwater Lowering Method in Osaka and Wakayama Plains 大阪和歌山平原地下水降压液化预测及对策
journal of the Japan Society for Testing Materials Pub Date : 2014-01-01 DOI: 10.2472/JSMS.63.614
Akihiko Oshima, Y. Hayashi, T. Hamada, Mari Kasugai
{"title":"Prediction of Liquefaction and Countermeasure due to Groundwater Lowering Method in Osaka and Wakayama Plains","authors":"Akihiko Oshima, Y. Hayashi, T. Hamada, Mari Kasugai","doi":"10.2472/JSMS.63.614","DOIUrl":"https://doi.org/10.2472/JSMS.63.614","url":null,"abstract":"The influence of groundwater rising for the liquefaction potential in Osaka and Wakayama plains was examined using GIS in which a digital database of underground information provided by Kansai Geo-informatics Database was introduced. The detailed geotechnical properties were calculated and given to Holocene sandy and clayey deposits that are representative value in each digital mesh of 250m × 250m areas. Then, liquefaction safety assessments were carried out by estimating pumping possible quantity of Holocene sandy deposits and considering negative effect of them against consolidation settlement problem that will occur in Holocene clayey deposits underneath. The efficacy of groundwater lowering method against liquefaction of Holocene sandy deposits was verified.","PeriodicalId":17366,"journal":{"name":"journal of the Japan Society for Testing Materials","volume":"11 1","pages":"614-619"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86288864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Deterioration Progress of Cement-Treated Ariake Clay under Seawater 海水作用下水泥处理有明黏土的劣化过程
journal of the Japan Society for Testing Materials Pub Date : 2014-01-01 DOI: 10.2472/JSMS.63.49
H. Hara, D. Suetsugu, S. Hayashi, H. Matsuda
{"title":"Deterioration Progress of Cement-Treated Ariake Clay under Seawater","authors":"H. Hara, D. Suetsugu, S. Hayashi, H. Matsuda","doi":"10.2472/JSMS.63.49","DOIUrl":"https://doi.org/10.2472/JSMS.63.49","url":null,"abstract":"1 緒 言 粘土に石灰やセメントを混合して,変形・強度特性を 改善させる固化処理工法は,軟弱地盤対策や建設発生土 の改良に利用されており,軟弱地盤が広く分布するわが 国では主要な工法となっている.しかしながら,固化処 理土は使用環境次第では,その性質が劣化することが明 らかになってきており,1)~ 3)長期的な耐久性に関する検討 が望まれる.著者らは現在までに室内試験より海水の影 響による固化処理土の性質変化や劣化機構の解明に関す る研究を行ってきている.4)~ 6)今後,沿岸域ならびに河川 の感潮域において造成された固化処理地盤を長期に亘っ て供用していくためには,海水に対する耐久性を明らか にする必要がある. 本論文では,海水環境下におけるセメント処理土の劣 化の進行について実験的に検討する.劣化の進行には, 種々の要因が影響すると予想されるが,既往の研究成果 から劣化の主要な原因となる接触する海水の濃度,固化 材添加量をパラメータとして有明粘土を母材としたセメ ント処理土の劣化した範囲を実験的に調べた.得られた 結果から,海水濃度と固化材添加量の影響を考慮した海 水環境下におけるセメント処理土の劣化速度の実験式を 提案した. 2 実 験 概 要 著者らは現在までの研究成果から,処理土の劣化の進 行はセメントの種類にかかわらず,同程度であることを実 験的に確認している.7), 8)本論文における実験では,一般 的な固化材である普通ポルトランドセメント(以下単にセ メント)を使用した.試料土には,佐賀県小城市の感潮 河川の河口域に堆積した有明粘土を用いた.試料土の物 性を Table 1に示す.粘土と固化材を均質に混合するた めに試料土の含水比を液性限界の 1.5倍 (w = 237.2%) に調 整して使用した.固化材の添加量は 50, 70, 100kg/m3で ある.含水比を調整した試料土に固化材を添加し,ミキ サーで十分に混合したものを φ = 50mm,H = 100mmの プラスチック製円筒形モールドに空気が入らないように タッピングしながら充填した.その後,供試体表面の乾 燥および酸化を防ぐために余盛りしてラップで覆い,恒 温恒湿器にて温度 20°C,湿度 80%の条件で 28日間養生 した. 海水環境下におけるセメント処理した有明粘土の 劣化の進行に関する検討 原 弘 行 末 次 大 輔 林 重 徳 松 田 博 Deterioration Progress of Cement-Treated Ariake Clay under Seawater","PeriodicalId":17366,"journal":{"name":"journal of the Japan Society for Testing Materials","volume":"28 1","pages":"49-54"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84701380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
The Effects of Fine Particle Peening on Surface Residual Stress of a TRIP-Aided Bainitic Ferrite Steel 细颗粒强化对trip辅助贝氏体铁素体钢表面残余应力的影响
journal of the Japan Society for Testing Materials Pub Date : 2014-01-01 DOI: 10.2472/JSMS.63.662
Masahiro Natori, Sung-Moo Song, K. Sugimoto
{"title":"The Effects of Fine Particle Peening on Surface Residual Stress of a TRIP-Aided Bainitic Ferrite Steel","authors":"Masahiro Natori, Sung-Moo Song, K. Sugimoto","doi":"10.2472/JSMS.63.662","DOIUrl":"https://doi.org/10.2472/JSMS.63.662","url":null,"abstract":"To apply a transformation-induced plasticity (TRIP)-aided steel consisting of bainitic ferrite structure matrix and metastable retained austenite of 10 vol% (TBF steel) to some precision gears, the effects of fine particle peening on the Vickers hardness and residual stress in a surface layer of the TBF steel were investigated. The peened surface layer showed much higher Vickers hardness and compressive residual stress than those of a quenched and tempered SNCM420 steel. The increased Vickers hardness was mainly caused by an increase in the strain-induced transformed martensite fraction. The compressive residual stress was increased by the increases in size and gravity of shot material and arc-height. The higher compressive residual stress was principally associated with (1) plastic strain due to severe plastic deformation and (2) expansion strain due to the strain-induced transformation of metastable retained austenite. Contribution of the (2) was approximately 30% of total residual stress.","PeriodicalId":17366,"journal":{"name":"journal of the Japan Society for Testing Materials","volume":"18 1","pages":"662-668"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81241047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 9
Permeability Test and Hydraulic Conductivity of Improved Soils by Deep Mixing Method 深层搅拌法改良土的渗透性试验及导流性能
journal of the Japan Society for Testing Materials Pub Date : 2014-01-01 DOI: 10.2472/JSMS.63.28
Kazuaki Hioki, Shumpei Iwanaga, Atsushi Hashimoto, Shigehiro Murakami
{"title":"Permeability Test and Hydraulic Conductivity of Improved Soils by Deep Mixing Method","authors":"Kazuaki Hioki, Shumpei Iwanaga, Atsushi Hashimoto, Shigehiro Murakami","doi":"10.2472/JSMS.63.28","DOIUrl":"https://doi.org/10.2472/JSMS.63.28","url":null,"abstract":"1 緒 言 通常,遮水壁の要求性能は,遮水壁内外に所定の水位 差を与えた場合の透水速度(Darcy流速)が管理型処分 場における底部遮水工の要件(『厚さ 5.0m以上,かつ透 水係数 kが 1.0 × 10−7m/s以下の地層』)と同等以上と なるよう,『厚さ 0.5m以上,かつ透水係数 kが 1.0 × 10−8m/s以下』と定められることが多い.しかし,本来, 遮水壁の要求性能は,式 (1)に示すように,有害物質を 含む浸透水が遮水壁中を通過する時間(以下,トラベル タイムと称す)で定められるべきであり(厳密には,有 害物質のトラベルタイムで定められるべきであるが,物 質移動パラメータの評価や管理が困難である),その性能 を“管理型処分場における底部遮水工の要件と同等以上” と評価するには,厚さ 0.5mの遮水壁に対して透水係数 kは 1.0 × 10−9m/s以下を満足しなければならない.1)","PeriodicalId":17366,"journal":{"name":"journal of the Japan Society for Testing Materials","volume":"101 1","pages":"28-31"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85634346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Fatigue Limit Estimation Based on Dissipated Energy Measurement for Shot Peened SUS 316L Steel 喷丸强化sus316l钢疲劳极限耗散能估算
journal of the Japan Society for Testing Materials Pub Date : 2014-01-01 DOI: 10.2472/JSMS.63.850
T. Inagawa, D. Shiozawa, A. Akai, K. Inaba, T. Sakagami
{"title":"Fatigue Limit Estimation Based on Dissipated Energy Measurement for Shot Peened SUS 316L Steel","authors":"T. Inagawa, D. Shiozawa, A. Akai, K. Inaba, T. Sakagami","doi":"10.2472/JSMS.63.850","DOIUrl":"https://doi.org/10.2472/JSMS.63.850","url":null,"abstract":"近年,機器の軽量化や,コンパクト化,製品寿命向上 の要求により,厳しい使用条件に耐えうる材料強度の向 上のために表面処理が構造部材に施されている.金属材 料の表面改質処理法の一つとして,ショットピーニング 処理が広く用いられている.ショットピーニング処理と は,ショットと呼ばれる投射材を金属材料表面に投射す ることで圧縮残留応力および加工硬化を与えることによ り母材の疲労限度を向上させる手法である.同手法につ いては疲労限度の上昇要因である圧縮残留応力,加工硬 化と同時に,疲労限度の低下要因である表面粗さや圧痕 も付与されてしまうため,疲労寿命が向上する一方で, 処理条件によっては逆に低下するという報告がある . そこで,ピーニング処理を行った表面改質材に対して迅 速かつ簡易に疲労限度の推定を行うことができれば,有 用なツールとなり得る. これまでのピーニング材に対する疲労特性の評価法と して,村上ら は圧痕を介在物と等価と考え,最大圧痕 部の投影面積から疲労限度を推定する√ パラメータ モデルと基地組織の硬さおよび圧縮残留応力から複合的 に疲労限度予測をした結果を述べている.また三林ら は疲労き裂進展解析を基礎とした破壊力学的観点から疲 労限度を推定している.政木ら は圧縮残留応力および 半価幅硬度分布と応力拡大係数を考慮して,ハードショ ットピーニングされた SUS316L 鋼の内部き裂起点の疲 労限度を推定している.このようにピーニング材に対し て種々の疲労限度推定法が考案されてきた. 一方で近年,散逸エネルギ測定に基づく疲労限度推定 法が注目されている.この手法は測定対象が繰返し負荷 を受けた場合に放出される散逸エネルギに起因する不可 逆発熱成分を赤外線サーモグラフィにより測定し,様々 な大きさの応力振幅に対する散逸エネルギの変化から疲 労限度を評価する手法である.著者ら ~ は,これまで に,炭素鋼 S45C やオーステナイト系ステンレス鋼に対 する本疲労限度推定法の適用性,さらには散逸エネルギ と疲労損傷メカニズムの関係について明らかにしてきた. 本報では,ショットピーニング処理を施した SUS316L 鋼試験片に対して,散逸エネルギに基づく疲労限度推定 法を適用し,表面改質材に対する本疲労限度推定法の適 用性について検討を行った.","PeriodicalId":17366,"journal":{"name":"journal of the Japan Society for Testing Materials","volume":"88 1","pages":"850-856"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82226657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Lead Removal By Scallop Shell Used for Crystallization Phosphorus Removal 结晶除磷用扇贝壳除铅
journal of the Japan Society for Testing Materials Pub Date : 2014-01-01 DOI: 10.2472/JSMS.63.442
K. Yoshimura, H. Shiomi
{"title":"Lead Removal By Scallop Shell Used for Crystallization Phosphorus Removal","authors":"K. Yoshimura, H. Shiomi","doi":"10.2472/JSMS.63.442","DOIUrl":"https://doi.org/10.2472/JSMS.63.442","url":null,"abstract":"Previously, we reported that on immersing the composite of crashed scallop shells and gypsum into KH 2 PO 4 aqueous solution, DCPD(CaHPO 4 ・ 2H 2 O) crystal precipitated on the surface of the composite and grew with increasing immersion time. In this study, the feasibility of using the scallop shells with DCPD precipitate after phosphate ion removal as an adsorbent of lead in waste water was evaluated. When the scallop shells with DCPD precipitate were immersed in an aqueous solution containing 50ppm Pb 2+ at pH3, the concentration of Pb 2+ in the solution deceased with increasing immersion time. The Pb 2+ removal rate largely depended on the amount of DCPD precipitate on the surface of the scallop shells and increased with the amount of DCPD precipitate. From the results of SEM observation, EDX and XRD analysis, it was found that after immersing scallop shells with DCPD precipitate in the Pb2+ aqueous solution, DCPD converted into HAP(Ca 10 (PO 4 ) 6 (OH) 2 ) and hydroxypyromophite(Pb 5 (PO 4 ) 3 OH, HPY) whisker precipitated on the surface of HAP crystal. When DCPD converts into HAP, surplus PO 43- ions dissolve into the solution and react with Pb 2+ ions to form Pb 5 (PO 4 ) 3 OH. There results show that the scallop shells used for the adsorbent of phosphate ions would be reused as the adsorbent of lead in wastewater.","PeriodicalId":17366,"journal":{"name":"journal of the Japan Society for Testing Materials","volume":"47 1","pages":"442-445"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75244845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Stiffness Reduction Process of CFRP under the Cyclic Bending Deformation 循环弯曲变形作用下CFRP的减刚度过程
journal of the Japan Society for Testing Materials Pub Date : 2014-01-01 DOI: 10.2472/JSMS.63.641
Yoshinori Yamada, T. Kadowaki, Toshihiko Sumiya, Masahiko Hata
{"title":"Stiffness Reduction Process of CFRP under the Cyclic Bending Deformation","authors":"Yoshinori Yamada, T. Kadowaki, Toshihiko Sumiya, Masahiko Hata","doi":"10.2472/JSMS.63.641","DOIUrl":"https://doi.org/10.2472/JSMS.63.641","url":null,"abstract":"Stiffness of carbon fiber reinforced polymer composites (CFRP) under the cyclic loading of bending deformation has been measured at various temperatures and deformation amplitudes. The stiffness of specimens decreases gradually with the number of loading cycles. The stiffness reduction correlates with the decrease in bending strength and the increase in viscoelastic loss, which suggests the stiffness reduction process corresponds to the damage accumulation process under the cyclic loading. The stiffness reduction process whose rates increase with increasing temperature and deformation amplitude, has been proved to be the thermally activated process depending on load stress (deformation amplitude). Analyzing the stiffness reduction curves at various temperatures and loads by means of reduced variable methods, a master curve that can be used to estimate a fatigue life has been composed, and an activation energy and an activation volume are estimated to be 26±3kcal/mole and 1.1×10 m 3 respectively. A molecular process for the stiffness reduction is discussed on the basis of the rate process theory.","PeriodicalId":17366,"journal":{"name":"journal of the Japan Society for Testing Materials","volume":"2 1","pages":"641-646"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90926572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Commentaries on Struggle of the First Year Postdoctoral 《博士后第一年奋斗述评
journal of the Japan Society for Testing Materials Pub Date : 2014-01-01 DOI: 10.2472/jsms.63.352
A. Shiro
{"title":"Commentaries on Struggle of the First Year Postdoctoral","authors":"A. Shiro","doi":"10.2472/jsms.63.352","DOIUrl":"https://doi.org/10.2472/jsms.63.352","url":null,"abstract":"(独)日本原子力研究開発機構量子ビーム応用研究部門 量子ビーム材料評価・構造制御技術研究ユニット弾塑性 材料評価研究グループ博士研究員.これが今の私の肩書で す.専門は放射光X線回折法を利用した材料の応力・ひ ずみ評価で,現在の研究テーマはアルミニウム単結晶に おける応力・ひずみと再結晶挙動に関する研究.これまで に塑性変形を与えた単結晶内の応力・ひずみ分布や,再 結晶挙動には転位が関連していることなどを放射光X線 の観点から明らかにしてきました. 学生時代を含め,大型放射光施設 SPring-8 に常駐して 3年近くが経過しました.当初は1ユーザーでしかなかっ た私も,今では機構の専用ビームラインの光学調整をこ なし,独自研究と並行してユーザーの実験サポートにまわ る立場になりました.多少の変動はあるものの,専用・ 共用ビームラインを合わせて年間 100 日近い実験に携わっ ており,施設の稼働期間は月の半分にビームタイムが連 結していることもままあります.最近は 2つのビームラ インで別々のユーザーが同時に実験し,どちらかを任せ た! と派遣されることもしばしば.こんな風に書くと “できる人”のように聞こえますが,決してそんなことは なく,経験値に基づくところが大きいです.極めて新規 性や難易度の高い実験については,自分の無知や無力さ をその度に痛感させられています.今回は,そんな大型 実験施設の内側からのぞいた材料評価という世界と,私 自身が日々感じていることについてご紹介したいと思い ます. SPring-8 は,ご存じのとおり世界最大級の大型放射光 施設です.周長 1.4kmの蓄積リング内に,60 本近いビー ムラインがあり,施設の稼働期間は各々のビームライン の特徴を活かした研究が昼夜実施されています.その中 で,応力やひずみ評価に利用された実績をもつビームラ インは 9本.回折計やそれに準ずる装置,アクセサリー があれば,一番単純な応力・ひずみ評価は可能であるた め,多くのビームラインで研究が実施できます.しかし, SPring-8 の放射光を利用して,ただ単純に応力やひずみ の評価を行うだけでは何の特異性もありません.そこは やはり,放射光の特徴を活かした,“ここでしかできない 研究”に注目が集まってきます. 近年の放射光を使用した応力測定でキーワードとして 挙げられるのが,微小部,その場(実環境),時分割の3 つです.特に最近は放射光に 2次元検出器が盛んに取り 入れられており,高温炉と組み合わせた焼鈍や再結晶,溶 接中その場測定など,早い時間スケールで起こる現象を1 秒以下の時間分解能で観察する技術が確立されつつあり ます.このように,装置や技術は高度化が進み,効率は 上がっていく一方で,時間的・精神的余裕はなくなって いるように思います.もちろん,限られた施設の稼働時 間の中で,最大限のビームタイムを確保するのは重要で あり,高効率化は極めて望ましいことです.しかしなが ら,昨今のすぐに業績が求められる風潮は,時間に急か されて試行錯誤の時間すら奪ってしまうように感じるこ とも多く,歯がゆく思っている側面もあります. 一方で,研究者にとって一番重要なのは業績であるこ ともまた事実です.研究の独創性,発想力,その研究結 果がもたらす恩恵と,世の中で求められている課題をタ イムリーに見通す力.それらを統合して,いかに面白い 研究を行い,いかに早く成果を公表して,業績につなげ ていくか.研究者の評価対象は業績が全てです.何より も業績が求められているポスドクのポジションにいる今, 博士後期課程の時に言われた,「研究者に努力賞はない」 という言葉の重みを痛感しています. ポスドク1年目,一流の研究者の方々の実験に参加さ せていただき,刺激を与えていただくと同時に,自分の 力量不足を感じる日々です.研究者は豊富な知識や経験 に加えて,体力やタフな精神力も必要であることを知り ました.まだまだ未熟者ではありますが,たゆみない興 味と好奇心を武器に,駆け出しの研究者は今日も第一線 で戦っています.今度は私が材料の新しい知見をお届け できるよう,“倍返し”ならぬ“恩返し”の心意気で, 日々努力していきます.","PeriodicalId":17366,"journal":{"name":"journal of the Japan Society for Testing Materials","volume":"64 1","pages":"352"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74513489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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