目的探索人工智能重建技术对颅内3D TOF MRA图像质量的改善。方法回顾性收集2021年8月至2022年6月在南京大学医学院附属鼓楼医院进行头颅磁共振检查的43例受试者,平均年龄为56.95±35岁。采集不同压缩感知因子及重建技术的3D TOF MR...目的探索人工智能重建技术对颅内3D TOF MRA图像质量的改善。方法回顾性收集2021年8月至2022年6月在南京大学医学院附属鼓楼医院进行头颅磁共振检查的43例受试者,平均年龄为56.95±35岁。采集不同压缩感知因子及重建技术的3D TOF MRM序列:CS4、CSAI4、CS8、CSAI8。定性分析四组图像血管显示能力、伪影、图像质量和诊断价值。采用F ri ed man检验比较四个序列间定性评分结果的差异。采用单因素重复测量方差分析定量比较四组图像CR值差异。结果图像质量定性分析中,在相同CS因子下,人工智能重建图像质量明显优于的常规CS重建图像(CSAI8:23.22±1.33 vs CS8;22.17+1.51,P<0.001;CSAI4:23.6±1.43 vs CS4:22.82±1.43,P<0.001)。图像定量分析中,人工智能重建的M RA图像CR值显著高于常规重建图像(大血管:CRCSAI4:11.10±0.75,CRCS4:9.10±0.48,CRCSAI8:10.75±0.75,CRCS8:7.86±0.38,P<0.001)。压缩感知加速因子不同时,CRCSAI8仍显著高于CRCS4(P<0.001)。结论人工智能重建技术可明显提高MRA图像质量。展开更多
在航空航天领域,单晶高温合金是发动机和燃气轮机热端部件制备的关键材料,然而其制备过程困难,常伴有微观缺陷的产生。其中,显微孔洞作为一类常见且危害较大的微观缺陷,对叶片性能影响显著,这一问题已成为科研人员关注的焦点。本文全面...在航空航天领域,单晶高温合金是发动机和燃气轮机热端部件制备的关键材料,然而其制备过程困难,常伴有微观缺陷的产生。其中,显微孔洞作为一类常见且危害较大的微观缺陷,对叶片性能影响显著,这一问题已成为科研人员关注的焦点。本文全面综述了单晶高温合金相关研究成果,首先详细介绍了定向凝固法制备单晶高温合金的过程,涵盖凝固原理、影响因素、常见技术以及单晶制备方法等方面;深入分析了显微孔洞的形成机制及其影响因素,着重探讨了固溶微孔和铸态微孔的形成过程与影响因素;进而提出一系列优化单晶高温合金性能的有效策略,包括凝固参数优化、热处理工艺改进以及合金成分设计等;最后对未来研究方向进行了展望,如探索新型制备技术(增材制造技术应用和微重力凝固技术研究)以及深化显微孔洞形成机制研究(多尺度模拟研究和原位表征技术应用)。本研究旨在为提升单晶高温合金性能、拓展其应用领域提供坚实的理论支撑,助力航空航天等高温领域的进一步发展。In the aerospace field, single crystal superalloys are crucial materials for the fabrication of hot-section components in engines and gas turbines. However, their manufacturing process is fraught with difficulties, often accompanied by the generation of microscopic defects. Among these, micropores, as a common and highly detrimental type of microscopic defect, have a significant impact on blade performance, which has become a focus of attention among researchers. This article comprehensively reviews the research findings related to single crystal superalloys. Firstly, it elaborates on the process of preparing single crystal superalloys using the directional solidification method, covering aspects such as the solidification principle, influencing factors, common techniques, and single crystal preparation methods. It then conducts an in-depth analysis of the formation mechanisms and influencing factors of micropores, with a particular emphasis on the formation processes and influencing factors of solution micropores and cast micropores. Subsequently, a series of effective strategies for optimizing the performance of single crystal superalloys are proposed, including the optimization of solidification parameters, improvement of heat treatment processes, and design of alloy compositions. Finally, future research directions are envisioned, such as the exploration of novel manufacturing techniques (application of additive manufacturing technology and research on microgravity solidification technology) and the in-depth study of the formation mechanisms of micropores (multi-scale simulation research and in-situ characterization technology application). The aim of this research is to provide a solid theoretical foundation for enhancing the performance and expanding the application fields of single crystal superalloys, thereby facilitating the further development of high-temperature fields such as aerospace.展开更多
文摘目的探索人工智能重建技术对颅内3D TOF MRA图像质量的改善。方法回顾性收集2021年8月至2022年6月在南京大学医学院附属鼓楼医院进行头颅磁共振检查的43例受试者,平均年龄为56.95±35岁。采集不同压缩感知因子及重建技术的3D TOF MRM序列:CS4、CSAI4、CS8、CSAI8。定性分析四组图像血管显示能力、伪影、图像质量和诊断价值。采用F ri ed man检验比较四个序列间定性评分结果的差异。采用单因素重复测量方差分析定量比较四组图像CR值差异。结果图像质量定性分析中,在相同CS因子下,人工智能重建图像质量明显优于的常规CS重建图像(CSAI8:23.22±1.33 vs CS8;22.17+1.51,P<0.001;CSAI4:23.6±1.43 vs CS4:22.82±1.43,P<0.001)。图像定量分析中,人工智能重建的M RA图像CR值显著高于常规重建图像(大血管:CRCSAI4:11.10±0.75,CRCS4:9.10±0.48,CRCSAI8:10.75±0.75,CRCS8:7.86±0.38,P<0.001)。压缩感知加速因子不同时,CRCSAI8仍显著高于CRCS4(P<0.001)。结论人工智能重建技术可明显提高MRA图像质量。
文摘在航空航天领域,单晶高温合金是发动机和燃气轮机热端部件制备的关键材料,然而其制备过程困难,常伴有微观缺陷的产生。其中,显微孔洞作为一类常见且危害较大的微观缺陷,对叶片性能影响显著,这一问题已成为科研人员关注的焦点。本文全面综述了单晶高温合金相关研究成果,首先详细介绍了定向凝固法制备单晶高温合金的过程,涵盖凝固原理、影响因素、常见技术以及单晶制备方法等方面;深入分析了显微孔洞的形成机制及其影响因素,着重探讨了固溶微孔和铸态微孔的形成过程与影响因素;进而提出一系列优化单晶高温合金性能的有效策略,包括凝固参数优化、热处理工艺改进以及合金成分设计等;最后对未来研究方向进行了展望,如探索新型制备技术(增材制造技术应用和微重力凝固技术研究)以及深化显微孔洞形成机制研究(多尺度模拟研究和原位表征技术应用)。本研究旨在为提升单晶高温合金性能、拓展其应用领域提供坚实的理论支撑,助力航空航天等高温领域的进一步发展。In the aerospace field, single crystal superalloys are crucial materials for the fabrication of hot-section components in engines and gas turbines. However, their manufacturing process is fraught with difficulties, often accompanied by the generation of microscopic defects. Among these, micropores, as a common and highly detrimental type of microscopic defect, have a significant impact on blade performance, which has become a focus of attention among researchers. This article comprehensively reviews the research findings related to single crystal superalloys. Firstly, it elaborates on the process of preparing single crystal superalloys using the directional solidification method, covering aspects such as the solidification principle, influencing factors, common techniques, and single crystal preparation methods. It then conducts an in-depth analysis of the formation mechanisms and influencing factors of micropores, with a particular emphasis on the formation processes and influencing factors of solution micropores and cast micropores. Subsequently, a series of effective strategies for optimizing the performance of single crystal superalloys are proposed, including the optimization of solidification parameters, improvement of heat treatment processes, and design of alloy compositions. Finally, future research directions are envisioned, such as the exploration of novel manufacturing techniques (application of additive manufacturing technology and research on microgravity solidification technology) and the in-depth study of the formation mechanisms of micropores (multi-scale simulation research and in-situ characterization technology application). The aim of this research is to provide a solid theoretical foundation for enhancing the performance and expanding the application fields of single crystal superalloys, thereby facilitating the further development of high-temperature fields such as aerospace.
