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Mechanisms of action of radon therapy on cytokine levels in normal mice and rheumatoid arthritis mouse model

片岡 隆浩*; 直江 翔太*; 村上 海斗*; 雪峰 諒平*; 藤本 有希*; 神崎 訓枝; 迫田 晃弘; 光延 文裕*; 山岡 聖典*

Journal of Clinical Biochemistry and Nutrition, 70(2), p.154 - 159, 2022/03

Radon therapy has been reported to be effective in the management of rheumatoid arthritis, an autoimmune disease caused by immune cell imbalance. Although there are several reports that suggest that radon therapy induces Th17 cells, there are no studies on the effects of radon inhalation on Th1, Th2, and Th17 immune balance. The aim of this study, therefore, was to examine the changes in cytokine levels after radon inhalation. BALB/c mice were subjected to radon inhalation at a concentration of 2000 Bq/m$${^3}$$ for 2 or 4 weeks, whereas SKG/Jcl mice were subjected to radon inhalation at a concentration of 2000 Bq/m$${^3}$$ for 4 weeks after zymosan administration. For example, the results showed that radon inhalation for 4 weeks not only activated Th1, Th2, and Th17 cells but also modulated immune balance. This suggests that radon inhalation has different mechanisms of action in SKG/Jcl mice and normal BABL/c mice and that radon inhalation has immunomodulatory effects.


Dynamic accommodation of internal stress and selection of crystallographic orientation relationship in pearlite

雨宮 雄太郎*; 中田 伸生*; 諸岡 聡; 小坂 誠*; 加藤 雅治*

ISIJ International, 62(2), p.282 - 290, 2022/02

To gain a deeper understanding of the dynamic accommodation mechanism of the internal stress in pearlite originating from the lattice misfit between ferrite and cementite phases, the lattice parameter ratios of cementite, b$$theta$$/a$$theta$$ and c$$theta$$/a$$theta$$, were locally analyzed in detail using the electron backscatter diffraction (EBSD) technique. The EBSD analysis revealed that the lattice parameter ratios of the cementite lamellae clearly differed from those of the spheroidized cementite particles, indicating that pearlite has a certain amount of internal stress as long as it maintains a lamellar structure. The internal stress in pearlite gradually decreased during the isothermal holding at 923 K after the pearlitic transformation due to the interfacial atomic diffusion of Fe atoms. However, a comparison with the theoretical values obtained from the Pitsch-Petch orientation relationship revealed that a large amount of internal stress had been already accommodated during the pearlitic transformation by the introduction of misfit dislocations and structural ledges on ferrite/cementite lamellar interfaces, i.e., the internal stress of pearlite is dynamically reduced by two different processes; built-in accommodation upon pearlitic transformation and additional time-dependent relaxation after pearlitic transformation. On the other hand, the analysis of the EBSD and neutron diffraction results yielded intriguingly different lattice parameters of cementite, indicating that various crystallographic orientation relationships between ferrite and cementite coexist in pearlite. Furthermore, the elastic strain energy analysis suggests that the invariant-line criterion on the ferrite/cementite interface plays an important role for the selection of orientation relationships in pearlite.


低線量・低線量率放射線被ばくによる臓器別酸化ストレス状態の検討(委託研究); 令和2年度英知を結集した原子力科学技術・人材育成推進事業

廃炉環境国際共同研究センター; 東北大学*

JAEA-Review 2021-050, 82 Pages, 2022/01




ラドンを代表としたアルファ核種の吸入による内部被ばくの横断的生体影響評価(委託研究); 令和2年度英知を結集した原子力科学技術・人材育成推進事業

廃炉環境国際共同研究センター; 岡山大学*

JAEA-Review 2021-028, 57 Pages, 2021/11




Work hardening behavior of dual phase copper-iron alloy at low temperature

山下 享介*; 古賀 紀光*; 川崎 卓郎; 諸岡 聡; 友野 翔平*; 梅澤 修*; Harjo, S.

Materials Science & Engineering A, 819, p.141509_1 - 141509_10, 2021/07

 被引用回数:0 パーセンタイル:0(Nanoscience & Nanotechnology)

In-situ neutron diffraction measurements were performed on a cold-rolled copper-iron (Cu-Fe) alloy during tensile tests at 293 K and 150 K. The roles of Cu and Fe on the deformation behavior of alloys were discussed and clarified. The strength and work-hardening rate of the alloy increased with decreasing test temperature. Furthermore, the phase stress of Fe increased considerably with decreasing test temperature; however, the response of this stress to the applied true stress exhibited no dependence on the temperature. The phase stresses of Cu changed only slightly with decreasing test temperature. However, the Cu phase stress response to the applied true stress increased with decreasing test temperature, indicating an increase in the work-hardening rate. The strengthening of Fe and the increase in the work-hardening of Cu contributed to an increase in the strength and work-hardening rate of the Cu-Fe alloy at low temperatures.


Analysis of residual stress in steel bar processed by cold drawing and straightening

西田 智*; 西野 創一郎*; 関根 雅彦*; 岡 勇希*; Harjo, S.; 川崎 卓郎; 鈴木 裕士; 森井 幸生*; 石井 慶信*

Materials Transactions, 62(5), p.667 - 674, 2021/05

 被引用回数:0 パーセンタイル:0(Materials Science, Multidisciplinary)

In this study, we used neutron diffraction to analyze in a non-destructive method the distribution of internal residual stress in a free-cutting steel bar processed by cold drawing and straightening. The residual stresses were successfully measured with excellent stress balance. The residual stresses generated by the cold-drawing process were reduced by subsequent straightening, and the distribution of residual stresses by finite element method (FEM) simulation was consistent with the measured values by neutron diffraction. As a result of the FEM analysis, it is assumed that the rod was subjected to strong tensile strains in the axial direction during the drawing process, and the residual stresses were generated when the rod was unloaded. Those residual stresses were presumably reduced by the redistribution of residual stresses in the subsequent straightening process.



鈴木 環輝*; 大川 鉄平*; Harjo, S.; 佐々木 敏彦*

日本機械学会論文集(インターネット), 87(894), p.20-00377_1 - 20-00377_15, 2021/02

The residual stress state inside the cruciform welded joints were measured using the pulsed neutron stress measurement method. The points of interest in this study are the weld toe and its interior. We also compared the cases with and without ultrasonic impact treatment (UIT), which is expected as a fatigue strength improvement technology. Furthermore, the case where tensile stress or compressive stress was applied after UIT treatment was also examined. The applied stresses at this time were 75% or 85% of the yield point, respectively. From the above, we considered the cause of the change in the residual stress on the surface after UIT treatment, which was clarified in the preliminary experiment, in the early stage of fatigue. As a result, the load after the UIT treatment caused plastic deformation in a part of the inside, which caused the redistribution of residual stress.


低線量・低線量率放射線被ばくによる臓器別酸化ストレス状態の検討(委託研究); 令和元年度英知を結集した原子力科学技術・人材育成推進事業

廃炉環境国際共同研究センター; 東北大学*

JAEA-Review 2020-048, 49 Pages, 2021/01




ラドンを代表としたアルファ核種の吸入による内部被ばくの横断的生体影響(委託研究); 令和元年度英知を結集した原子力科学技術・人材育成推進事業

廃炉環境国際共同研究センター; 岡山大学*

JAEA-Review 2020-029, 55 Pages, 2020/12




Plasticity correction on stress intensity factor evaluation for underclad cracks in reactor pressure vessels

Lu, K.; 勝山 仁哉; Li, Y.

Journal of Pressure Vessel Technology, 142(5), p.051501_1 - 051501_10, 2020/10

 被引用回数:0 パーセンタイル:0(Engineering, Mechanical)

Structural integrity assessment of reactor pressure vessels (RPVs) is essential for the safe operation of nuclear power plants. For RPVs in pressurized water reactors (PWRs), the assessment should be performed by considering neutron irradiation embrittlement and pressurized thermal shock (PTS) events. To assess the structural integrity of an RPV, a traditional method is usually employed by comparing fracture toughness of the RPV material with the stress intensity factor ($$K_{rm I}$$) of a crack postulated near the RPV inner surface. When an underclad crack (i.e., a crack beneath the cladding of an RPV) is postulated, $$K_{rm I}$$ of this crack can be increased owing to the plasticity effect of cladding. This is because the yield stress of cladding is lower than that of base metal and the cladding may yield earlier than base metal. In this paper, detailed three-dimensional (3D) finite element analyses (FEAs) were performed in consideration of the plasticity effect of cladding for underclad cracks postulated in Japanese RPVs. Based on the 3D FEA results, a plasticity correction method was proposed on $$K_{rm I}$$ calculations of underclad cracks. In addition, the effects of RPV geometries and loading conditions were investigated using the proposed plasticity correction method. Moreover, the applicability of the proposed method to the case which considers the hardening effect of materials after neutron irradiation was also investigated. All of these results indicate that the proposed plasticity correction method can be used for $$K_{rm I}$$ calculations of underclad cracks and is applicable to structural integrity assessment of Japanese RPVs containing underclad cracks.



青柳 和平; 櫻井 彰孝; 宮良 信勝; 杉田 裕

JAEA-Research 2020-004, 68 Pages, 2020/06





青木 智幸*; 谷 卓也*; 坂井 一雄*; 古賀 快尚*; 青柳 和平; 石井 英一

JAEA-Research 2020-002, 83 Pages, 2020/06




Fracture-mechanics-based evaluation of failure limit on pre-cracked and hydrided Zircaloy-4 cladding tube under biaxial stress states

Li, F.; 三原 武; 宇田川 豊; 天谷 政樹

Journal of Nuclear Science and Technology, 57(6), p.633 - 645, 2020/06

 被引用回数:0 パーセンタイル:0.01(Nuclear Science & Technology)

To better understand the failure limit of fuel cladding during the pellet-cladding mechanical interaction (PCMI) phase of a reactivity-initiated accident (RIA), pre-cracked and hydrided cladding samples with base metal final heat-treatment status of cold worked (CW) and recrystallized (RX) were tested under biaxial stress conditions (axial to hoop strain ratios of 0 and 0.5). Displacement-controlled biaxial-expansion-due-to-compression (biaxial-EDC) tests were performed to obtain the hoop strain at failure (failure strain) of the samples. The conversion of the failure strains to J-integral at failure by finite-element analysis involving data of stress-relieved (SR) cladding specimens from our previous study revealed that the failure limit in the dimension of J-integral at failure unifies the effects of pre-crack depth. About 30 to 50 percent reduction in the J-integral at failure was observed as the strain ratio increased from 0 to 0.5 irrespective of the annealing type, pre-crack depth, and hydrogen content. the rate of fractional decreases of J-integral at failure with increase of hydrogen content are in the order of CW$$>$$SR$$>$$RX, which are essentially independent of strain ratio for the CW and SR samples. The results were incorporated into the failure prediction model of the JAEA's fuel performance code in the form of a correction factor that considers the biaxial loading effect.


Residual stress distribution in water jet peened type 304 stainless steel

林 眞琴*; 大城戸 忍*; 鈴木 裕士

Quantum Beam Science (Internet), 4(2), p.18_1 - 18_12, 2020/06

In materials with a surface treatment such as shot peening, the residual stress gradient in the surface layer is severe. When measuring the residual stress distribution near the surface with a severe stress gradient by the neutron diffraction method, the gauge volume must be removed from the measurement sample. However, when the gauge volume deviates from the sample, a pseudo peak shift occurs and accurate stress distribution cannot be evaluated. Therefore, it is necessary to evaluate the pseudo peak shift in advance under the same conditions, as in the case of actual residual stress measurement, using a sample in an unstressed state. In this study, the stress distributions in the surface layer of a type 304 stainless steel plate and bar with simulated stress-corrosion cracks which were subjected to water jet peening - giving a surface layer residual stress equivalent better than that of normal shot peening - were evaluated considering the pseudo peak shift. As a result, the residual stress distributions in the surface layer were measured in good agreement with the measurement result obtained by the sequential polishing X-ray diffraction method. It was clarified that the residual stress distribution in the near surface with steep stress gradient can be evaluated by the neutron diffraction method.


ラドンを代表としたアルファ核種の吸入による内部被ばくの横断的生体影響評価(委託研究); 平成30年度英知を結集した原子力科学技術・人材育成推進事業

廃炉国際共同研究センター; 岡山大学*

JAEA-Review 2019-024, 61 Pages, 2020/01




Experimental evaluation of wall shear stress in a double contraction nozzle using a water mock-up of a liquid Li target for an intense fusion neutron source

近藤 浩夫*; 金村 卓治*; 朴 昶虎*; 小柳津 誠*; 平川 康; 古川 智弘

Fusion Engineering and Design, 146(Part A), p.285 - 288, 2019/09

 被引用回数:0 パーセンタイル:0.01(Nuclear Science & Technology)



Neutron diffraction study on full-shape Japanese sword

Harjo, S.; 川崎 卓郎; Grazzi, F.*; 篠原 武尚; 田中 眞奈子*

Materialia, 7, p.100377_1 - 100377_9, 2019/09

A mapping measurement using pulsed neutron diffraction with time-of-flight method is performed on a full-shape Japanese sword made in Keicho era (1596-1615) to elucidate the manufacturing process. The obtained diffraction patterns are analyzed by the Rietveld refinement and a line profile analysis. The constituent phases in the area closer to the back of the blade (ridge) are found to be ferrite and cementite, composing pearlite, while the area close to the edge is composed by martensite and austenite. The distributions of constituent phases are well explained with the distributions of dislocation density and crystallite size. The carbon contents and the residual macroscopic stresses are estimated from the obtained phase fractions and lattice parameters.


Plastic collapse stresses based on flaw combination rules for pipes containing two circumferential similar flaws

長谷川 邦夫; Li, Y.; Kim, Y.-J.*; Lacroix, V.*; Strnadel, B.*

Journal of Pressure Vessel Technology, 141(3), p.031201_1 - 031201_5, 2019/06

 被引用回数:0 パーセンタイル:0(Engineering, Mechanical)




吉澤 厚文*; 大場 恭子; 北村 正晴*

日本原子力学会和文論文誌, 18(2), p.55 - 68, 2019/06

本研究は、東京電力福島第一原子力発電所の緊急時対策本部における事故時のワークロードマネジメントを分析することにより、緊急時対応力向上を目的としたものである。選定した事象は、緊急時対応力が求められた福島第一原子力発電所の3号機におけるHPCIの停止による原子炉注水停止から、原子炉への注水回復を暫定的に回復することに成功した時間帯の緊急時対策本部の対応である。テレビ会議システムの映像を文字起こししたデータを基本データとし、会議録では事実関係の把握が難しい時には、各報告書や調書を参照した。また、ワークロードマネジメントを評価する手法は、Crew Resource Managementの手法を参照した。本研究により、発電所対策本部のワークロードマネジメントの実態が明らかになるとともに、緊急対応力向上のために、発電所対策本部および関係する外部組織に求められる課題が明らかになった。


Intergranular strains of plastically deformed austenitic stainless steel

鈴木 賢治*; 菖蒲 敬久

E-Journal of Advanced Maintenance (Internet), 10(4), p.9 - 17, 2019/02


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