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Numerical Investigation on Residual Stresses of the Safe-End/Nozzle Dissimilar Metal Welded Joint in CAP1400 Nuclear Power Plants

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Acta Metallurgica Sinica(English Letters) 2019年第5期32卷 618-628页

作者： Wen-Chao Dong Dian-Bao Gao shan-ping lu Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences Nuclear Power and Petro-chemical Business Group China First Heavy Industries

The residual stress evolution in a safe-end/nozzle dissimilar metal welded joint of CAP1400 nuclear power plants was investigated in the manufacturing process by finite element simulation. A finite element model, including cladding,buttering, post-weld heat treatment (PWHT) and dissimilar metal multi-pass welding, is developed based on SYSWELD software to investigate the evolution of residual stress in the aforementioned manufacturing process. The results reveal a large tensile axial residual stress, which exists at the weld zone on the inner surface, leads to a high sensitivity to stress corrosion cracking (SCC). PWHT process before dissimilar metal multi-pass welding process has a great in?uence on the magnitude and distribution of final axial residual stress. The risk of SCC on the inner surface of the pipe will increase if PWHT process is not taken into account. Therefore, such crucial thermal manufacturing process such as cladding, buttering and post-weld heat treatment, besides the multi-pass welding process, should be considered in the numerical model in order to accurately predict the distribution and the magnitude of the residual stress.

关键词： CAP1400 nuclear power plants Nozzle Safe-end Dissimilar metal welding Residual stress

Effect of Nb and Mo on the Microstructure, Mechanical Properties and Ductility-Dip Cracking of Ni–Cr–Fe Weld Metals

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Acta Metallurgica Sinica(English Letters) 2016年第10期29卷 928-939页

作者： Xu Zhang Dian-Zhong Li Yi-Yi Li shan-ping lu Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences

A series of Ni-Cr-Fe welding wires with different Nb and Mo contents were designed to investigate the effect of Nb and Mo on the rnicrostructure, mechanical properties and the ductility-dip cracking susceptibility of the weld metals by optical microscopy （OM）, scanning electron microscopy, X-ray diffraction as well as the tensile and impact tests. Results showed that large Laves phases formed and distributed along the interdendritic regions with high Nb or Mo addition. The Cr-carbide （M23C6） was suppressed to precipitate at the grain boundaries with high Nb addition. Tensile testing indicates that the ultimate strength of weld metals increases with Nb or Mo addition. However, the voids formed easily around the large Laves phases in the interdendritic area during tensile testing for the weld metal with high Mo content. It is found that the tensile fractographs of high Mo weld metals show a typical feature of interdendritic fracture. The high Nb or Mo addition, which leads to the formation of large Laves phases, exposes a great weakening effect on the impact toughness of weld metals. In addition, the ductility-dip cracking was not found by OM in the selected cross sections of weld metals with different Nb additions. High Nb addition can eliminate the ductility-dip cracking from the Ni-Cr-Fe weld metals effectively.

关键词： Nb Mo Laves phase Microstructure Mechanical properties

Effect of Post-weld Tempering on the Microstructure and Mechanical Properties in the Simulated HAZs of a High-Strength-High-Toughness Combination Marine Engineering Steel

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Acta Metallurgica Sinica(English Letters) 2020年第3期33卷 391-402页

作者： Wen-Chao Dong Ming-Yue Wen Hui-Yong Pang shan-ping lu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Wuyang Iron and Steel Co.Ltd. Pingdingshan 462500China

The effects of tempering temperatures on the microstructure and mechanical properties of the simulated coarse-grain heataffected zone(CGHAZ) and inter-critical heat-affected zone(ICHAZ) were investigated for a high-strength-high-toughness combination marine engineering *** results demonstrate that the microstructure of the simulated CGHAZ and ICHAZ after tempering is characterized by tempering sorbites and coarse grain in the simulated *** tempering temperature increases,the tensile strength of the simulated CGHAZ and ICHAZ decreases and the Charpy absorbed energy of the simulated ICHAZ at-50℃increases remarkably,but the impact toughness of the simulated CGHAZ is not *** tempering at 550℃,the coarse flake carbides,which distribute at the prior austenite grain and martensite lath boundaries,deteriorate the impact toughness of the simulated *** the increase in tempering temperature,the morphology and the size of the carbides gradually change from coarse flake to fine granular,which is beneficial to the improvement of impact ***,the coarse-grain size of the simulated CGHAZ and the M23 C6-type carbide precipitated along the grain boundaries weakens the enhancing effect of carbides on impact toughness.

关键词： High-strength-high-toughness combination steel Post-weld heat treatment Heat-affected zones(HAZs) Carbides Impact toughness

Numerical simulation and control of welding distortion for double floor structure of high speed train

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Acta Mechanica Sinica 2014年第6期30卷 849-859页

作者： Wen-Chao Dong shan-ping lu Hao lu Dian-Zhong Li Li-Jian Rong Yi-Yi Li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences CSR Qingdao Sifang Co. Ltd.

The welding heat source models and the plastic tension zone sizes of a typical weld joint involved in the double floor structure of high speed train under different welding parameters were calculated by a thermal-elastic-plastic FEM analysis based on SYSWELD ***,the welding distortion of floor structure was predicted using a linear elastic FEM and shrinkage method based on Weld Planner *** effects of welding sequence,clamping configuration and reverse deformation on welding distortion of floor structure were examined *** results indicate that the established elastic FEM model for floor structure is reliable for predicting the distribution of welding distortion in view of the good agreement between the calculated results and the measured distortion for real double floor *** with the welding sequence,the clamping configuration and the reverse deformation have a significant influence on the welding distortion of floor *** the case of30 mm reverse deformation,the maximum deformation can be reduced about 70%in comparison to an actual welding process.

关键词： Welding distortion Double floor welded structure High speed train Numerical simulation

Acute and chronic excitotoxicity in ischemic stroke and late-onset Alzheimer's disease

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Neural Regeneration Research 2025年第7期20卷 1981-1988页

作者： shan ping Yu Emily Choi Michael QJiang Ling Wei Department of Anesthesiology Emory University School of MedicineAtlantaGAUSA Center for Visual and Neurocognitive Rehabilitation Atlanta Veterans Affairs Medical CenterDecaturGAUSA

Stroke and Alzheimer's disease are common neurological disorders and often occur in the same *** comorbidity of the two neurological disorders represents a grave health threat to older *** review presents a brief background of the development of novel concepts and their clinical *** activity of glutamatergic N-methyl-D-aspartate receptors and N-methyl-D-aspartate receptor-mediated Ca^(2+)influx is critical for neuronal *** ischemic insult induces prompt and excessive glutamate release and drastic increases of intracellular Ca^(2+)mainly via N-methyl-D-aspartate receptors,particularly of those at the extrasynaptic *** Ca^(2+)-evoked neuronal cell death in the ischemic core is dominated by necrosis within a few hours and days known as acute ***,mild but sustained Ca^(2+)increases under neurodegenerative conditions such as in the distant penumbra of the ischemic brain and early stages of Alzheimer's disease are not immediately toxic,but gradually set off deteriorating Ca^(2+)-dependent signals and neuronal cell loss mostly because of activation of programmed cell death *** on the Ca^(2+)hypothesis of Alzheimer's disease and recent advances,this Ca^(2+)-activated“silent”degenerative excitotoxicity evolves from years to decades and is recognized as a unique slow and chronic *** N-methyl-D-aspartate receptor subunit GluN3A,primarily at the extrasynaptic site,serves as a gatekeeper for the N-methyl-D-aspartate receptor activity and is neuroprotective against both acute and chronic *** stroke and Alzheimer's disease,therefore,share an N-methyl-D-aspartate receptor-and Ca^(2+)-mediated mechanism,although with much different time *** is thus proposed that early interventions to control Ca^(2+)homeostasis at the preclinical stage are pivotal for individuals who are susceptible to sporadic late-onset Alzheimer's disease and Alzheimer's disease-related

关键词： Ca^(2+)hypothesis cognitive deficits hyperactivity late-onset Alzheimer's disease neurodegeneration N-methyl-D-aspartate receptors N-methyl-D-aspartate receptor subunits pathogenesis preventive treatment

闽江口短叶茳芏+芦苇沼泽湿地大、小潮日土壤间隙水溶解性CH_4与CO_2浓度日动态

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环境科学 2017年第1期38卷 52-59页

作者：谭立山杨平何露露黄佳芳胡智强仝川福建师范大学地理科学学院福州350007 福建师范大学湿润亚热带生态地理过程教育部重点实验室福州350007 福建师范大学亚热带湿地研究中心福州350007

研究河口感潮沼泽湿地土壤间隙水溶解性CO_2和CH_4浓度日动态对于揭示河口湿地碳循环过程具有重要作用.于2010年的4月4~5日和9月2~3日(小潮日)和4月14~15日和9月9~10日(大潮日),对闽江河口鳝鱼滩中部中高潮滩过渡区分布的短叶茳芏(Cyper... 详细信息

研究河口感潮沼泽湿地土壤间隙水溶解性CO_2和CH_4浓度日动态对于揭示河口湿地碳循环过程具有重要作用.于2010年的4月4~5日和9月2~3日(小潮日)和4月14~15日和9月9~10日(大潮日),对闽江河口鳝鱼滩中部中高潮滩过渡区分布的短叶茳芏(Cyperus malaccensis)+芦苇(Phragmites australis)沼泽湿地的土壤间隙水溶解性CO_2和CH_4浓度进行24 h连续监测,并同步测定了原位土壤温度、电导率及NH+4-N等参数.结果表明:14月与9月大、小潮日土壤间隙水溶解性CH_4浓度日变化范围分别介于88.20~190.74、53.42~141.24、16.27~81.89和44.90~88.53μmol·L^(-1),其中4月大、小潮日土壤间隙水溶解性CH_4浓度均呈现昼低夜高特征(P>0.05),而9月大、小潮日呈现相反的日变化趋势(P<0.05);29月大、小潮日土壤间隙水溶解性CO_2浓度日变化范围分别介于19.33~40.1μmol·L^(-1)和9.69~29.96μmol·L^(-1),均呈现昼低夜高特征(P<0.01);3涨潮期间土壤间隙水溶解性CO_2浓度均要低于涨潮前与落潮后,而涨潮期间土壤间隙水溶解性CH_4浓度高于涨潮前和落潮后.

关键词：间隙水溶解性CH4 溶解性CO2 大、小潮日日变化河口湿地

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输电线动力学分析中的找形研究

电网与清洁能源 2009年第10期25卷 43-47页

作者：孟遂民单鲁平三峡大学机械与材料学院湖北宜昌443002

输电线静态平衡位置找形是动力学分析的前提,找形精确与否对后续分析结果有很大影响。介绍了输电线找形中的解析法和有限元法,以某跨越档为例,分别对导线在自重和覆冰荷载下进行找形,着重分析了非均布荷载作用下这2种方法找形的差异。... 详细信息

输电线静态平衡位置找形是动力学分析的前提,找形精确与否对后续分析结果有很大影响。介绍了输电线找形中的解析法和有限元法,以某跨越档为例,分别对导线在自重和覆冰荷载下进行找形,着重分析了非均布荷载作用下这2种方法找形的差异。结果表明,均布荷载作用时,解析法和有限元法对导线静态平衡位置找形有相同的效果;非均布荷载作用时,有限元法得到的结果相对准确。

关键词：找形解析法有限元法几何非线性

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城市电网高压电缆运维技术探讨

机电工程技术 2014年第2期43卷 25-28页

作者：卞佳音单鲁平广州供电局有限公司广东广州510310

随着社会经济发展,城市电缆线路的设备规模与日俱增,给电缆运行管理人员带来前所未有的挑战。根据城市高压电缆运行及管理工作的特点,分析了城市电缆运行面临的问题,结合实际运行中的经验,介绍了高压电缆设备全生命周期管理要点和电缆... 详细信息

随着社会经济发展,城市电缆线路的设备规模与日俱增,给电缆运行管理人员带来前所未有的挑战。根据城市高压电缆运行及管理工作的特点,分析了城市电缆运行面临的问题,结合实际运行中的经验,介绍了高压电缆设备全生命周期管理要点和电缆线路防外力破坏措施,并对线路和隧道全面的状态监测及新技术新设备的研究工作进行了阐述。

关键词：城市电网电缆全生命周期状态监测

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硅片真空传输平台前端真空室的研制

组合机床与自动化加工技术 2017年第9期 122-124,128页

作者：李学威鲍君善路平何书龙沈阳新松机器人自动化股份有限公司沈阳110168

文章设计并研制了8英寸硅片真空传输平台,介绍了该传输平台的整体结构,并对关键模块前端传输腔室VCE中的CTA传输手托盘系统进行了选型设计、机构分析。垂直升降系统采用丝杠传动,CTA传输手采用平面四连杆机构增大刚度。对传输手主动杆... 详细信息

文章设计并研制了8英寸硅片真空传输平台,介绍了该传输平台的整体结构,并对关键模块前端传输腔室VCE中的CTA传输手托盘系统进行了选型设计、机构分析。垂直升降系统采用丝杠传动,CTA传输手采用平面四连杆机构增大刚度。对传输手主动杆强度和变形量进行了有限元仿真分析。经过重复运行精度实验测试,整个平台达到了硅片制造要求。

关键词：硅片真空传输有限元