The impact of casting defects on the weldability of K4951 superalloy was investigated using tungsten inert gas(TIG)welding.The as-cast K4951 superalloy samples with prefabricated U-shaped grooves of varying depths and...The impact of casting defects on the weldability of K4951 superalloy was investigated using tungsten inert gas(TIG)welding.The as-cast K4951 superalloy samples with prefabricated U-shaped grooves of varying depths and widths were TIG welded,and the microstructures,cracks morphology,and precipitated phases were analyzed using optical microscope,scanning electron microscope,transmission electron microscope,and energy dispersive X-ray spectrometer.The results reveal that the dimensions of casting defects significantly affect the weldability of K4951.Deep defects(greater than 2 mm)lead to rapid crack propagation,while wider defects can moderate the propagation process of cracks.Elemental segregation and the formation of precipitated phases,such as MC carbides,are observed in the fusion zone,contributing to welding cracks.An optimal groove aspect ratio(depth-to-width)between 0.2 and 0.5 minimizes crack formation tendency and enhances tensile strength,resulting in a mixed brittle-ductile fracture mode of joint after high-temperature tensile testing.展开更多
目的分析和评价多发性骨髓瘤患者的运动体验,为制定个性化运动方案和提高患者运动积极性提供参考。方法检索PubMed、Cochrane Library、CINAHL Complete、Web of Science、Embase、SPORTDiscus、中国知网、万方数据知识服务平台、维普...目的分析和评价多发性骨髓瘤患者的运动体验,为制定个性化运动方案和提高患者运动积极性提供参考。方法检索PubMed、Cochrane Library、CINAHL Complete、Web of Science、Embase、SPORTDiscus、中国知网、万方数据知识服务平台、维普资讯中文期刊服务平台、中国生物医学文献数据库中有关多发性骨髓瘤患者运动体验质性研究的文献,检索时限为建库至2024年3月。采用澳大利亚乔安娜布里格斯研究所循证卫生保健中心质性研究质量评价标准进行方法学质量评价,采用Meta整合方法合并研究结果。结果共纳入8篇文献,提炼23个研究结果,归纳形成10个新类别,综合成4个整合结果,为感知运动的益处和潜在风险、开展运动困境重重、运动的内外驱动力、对运动方案设计的需求。结论多发性骨髓瘤患者的运动现状不容乐观,医护人员需要关注患者运动过程中的真实感受,加强风险评估,根据患者需求和障碍因素制定个性化的运动方案,提高患者的运动康复管理能力。展开更多
基金National Natural Science Foundation of China(52201054,52175368)National Science and Technology Major Projects(J2019-VI-0018-0133)+2 种基金Liaoning Provincial Science and Technology Program(2023-BS-019,2023-MS-020)National Key R&D Program of China(2021YFB3700401)Key Specialized Research and Development Break-Through-Unveiling and Commanding the Special Project Program in Liaoning Province(2021JH15)。
文摘The impact of casting defects on the weldability of K4951 superalloy was investigated using tungsten inert gas(TIG)welding.The as-cast K4951 superalloy samples with prefabricated U-shaped grooves of varying depths and widths were TIG welded,and the microstructures,cracks morphology,and precipitated phases were analyzed using optical microscope,scanning electron microscope,transmission electron microscope,and energy dispersive X-ray spectrometer.The results reveal that the dimensions of casting defects significantly affect the weldability of K4951.Deep defects(greater than 2 mm)lead to rapid crack propagation,while wider defects can moderate the propagation process of cracks.Elemental segregation and the formation of precipitated phases,such as MC carbides,are observed in the fusion zone,contributing to welding cracks.An optimal groove aspect ratio(depth-to-width)between 0.2 and 0.5 minimizes crack formation tendency and enhances tensile strength,resulting in a mixed brittle-ductile fracture mode of joint after high-temperature tensile testing.
文摘目的分析和评价多发性骨髓瘤患者的运动体验,为制定个性化运动方案和提高患者运动积极性提供参考。方法检索PubMed、Cochrane Library、CINAHL Complete、Web of Science、Embase、SPORTDiscus、中国知网、万方数据知识服务平台、维普资讯中文期刊服务平台、中国生物医学文献数据库中有关多发性骨髓瘤患者运动体验质性研究的文献,检索时限为建库至2024年3月。采用澳大利亚乔安娜布里格斯研究所循证卫生保健中心质性研究质量评价标准进行方法学质量评价,采用Meta整合方法合并研究结果。结果共纳入8篇文献,提炼23个研究结果,归纳形成10个新类别,综合成4个整合结果,为感知运动的益处和潜在风险、开展运动困境重重、运动的内外驱动力、对运动方案设计的需求。结论多发性骨髓瘤患者的运动现状不容乐观,医护人员需要关注患者运动过程中的真实感受,加强风险评估,根据患者需求和障碍因素制定个性化的运动方案,提高患者的运动康复管理能力。
