超高温氧化物陶瓷凭借优异的高温强度、高温组织稳定性、抗氧化和耐腐蚀等特性,有望成为在高温氧化环境下长期服役的新一代超高温结构材料,在航空航天领域具有广泛的应用前景。激光增材制造(Laser Additive Manufacturing,LAM)技术具有...超高温氧化物陶瓷凭借优异的高温强度、高温组织稳定性、抗氧化和耐腐蚀等特性,有望成为在高温氧化环境下长期服役的新一代超高温结构材料,在航空航天领域具有广泛的应用前景。激光增材制造(Laser Additive Manufacturing,LAM)技术具有快速近净成型、无需模具以及灵活制造复杂形状等优点,近年来被应用于超高温氧化物陶瓷的制备并成为研究热点。然而陶瓷在LAM过程中极易产生孔隙缺陷,其不仅不利于试样的后续沉积,而且易恶化成型样件表面质量与力学性能。本文首先概述了选区激光烧结(Selective Laser Sintering,SLS)、激光粉末床熔融(Laser Power Bed Fusion,LPBF)和激光定向能量沉积(Laser Directed Energy Deposition,LDED)三种LAM技术的基本原理及工艺特点,重点分析了LAM超高温氧化物陶瓷过程中的孔隙缺陷特征、熔池流动特点及孔隙缺陷的形成机理,并从工艺参数优化、外场辅助和第二相掺杂三个方面详细阐述了LAM超高温氧化物陶瓷孔隙缺陷抑制的研究进展。最后,总结了LAM超高温氧化物陶瓷实现工程化应用面临的挑战,并在成型缺陷抑制、粉末特性和后续热处理工艺等方面展望了该领域的发展趋势和突破点。展开更多
OBJECTIVE:To assess the effect of case-based learning(CBL)in the education of Traditional Chinese Medicine(TCM).METHODS:The studies concerning TCM courses designed with CBL were included by searching the databases of ...OBJECTIVE:To assess the effect of case-based learning(CBL)in the education of Traditional Chinese Medicine(TCM).METHODS:The studies concerning TCM courses designed with CBL were included by searching the databases of EBSCO,Pubmed,Science Citation Index,China National Knowledge Infrastructure,Chongqing VIP database.The valid data was extracted in accordance with the included criteria.The quality of the studies was assessed with Gemma Flores-Masteo.RESULTS:A total of 22 articles were retrieved that met the selection criteria:one was of high quality;two were of low quality;the rest were categorized as moderate quality.The majority of the studiesdemonstrated the better effect produced by CBL,while a few studies showed no difference,compared with the didactic format.All included studies confirmed the favorable effect on learners'attitude,skills and ability.CONCLUSION:CBL showed the desirable results in achieving the goal of learning.Compared to didactic approach,it played a more active role in promoting students'competency.Since the quality of the articles on which the study was based was not so high,the findings still need further research to become substantiated.展开更多
背景:正畸力通过多种信号通路激活牙周组织自噬,进一步增强或减弱相关细胞(牙周膜细胞、骨细胞、破骨细胞和成骨细胞等)的活性来促进牙周重塑。目的:综述目前正畸力介导牙周组织自噬的研究进展和其对正畸牙齿移动的影响。方法:在PubMed...背景:正畸力通过多种信号通路激活牙周组织自噬,进一步增强或减弱相关细胞(牙周膜细胞、骨细胞、破骨细胞和成骨细胞等)的活性来促进牙周重塑。目的:综述目前正畸力介导牙周组织自噬的研究进展和其对正畸牙齿移动的影响。方法:在PubMed、Web of Science、中国生物医学文献数据库和中国知网数据库进行文献检索,设置检索时限为2010-2023年,总结了2010年以来正畸与自噬相关研究进展,最终纳入76篇文献进行分析讨论。结果与结论:(1)正畸力可通过牙周机械感受器和其造成的无菌性炎症引发一系列生物化学信号的转变,进而引起牙周组织自噬。(2)自噬通过级联放大的信号通路如磷脂酰肌醇-3-激酶/蛋白激酶B通路、河马通路及丝裂原活化蛋白激酶通路等,产生相应反馈从而促进牙周组织改建,最终实现牙齿的移动与稳定。正畸力诱导的自噬可差异性调节牙齿压力侧骨吸收和张力侧骨形成,相关靶点在正畸临床治疗的应用中具有良好前景。(3)然而,正畸力与自噬的机制较为复杂,现有研究仅停留在探究自噬对正畸牙齿移动的作用,自噬与正畸牙齿移动过程中的相互调节作用、涉及相关通路上游机械受体及信号通路间的交互作用均需要进一步的探究。展开更多
文摘超高温氧化物陶瓷凭借优异的高温强度、高温组织稳定性、抗氧化和耐腐蚀等特性,有望成为在高温氧化环境下长期服役的新一代超高温结构材料,在航空航天领域具有广泛的应用前景。激光增材制造(Laser Additive Manufacturing,LAM)技术具有快速近净成型、无需模具以及灵活制造复杂形状等优点,近年来被应用于超高温氧化物陶瓷的制备并成为研究热点。然而陶瓷在LAM过程中极易产生孔隙缺陷,其不仅不利于试样的后续沉积,而且易恶化成型样件表面质量与力学性能。本文首先概述了选区激光烧结(Selective Laser Sintering,SLS)、激光粉末床熔融(Laser Power Bed Fusion,LPBF)和激光定向能量沉积(Laser Directed Energy Deposition,LDED)三种LAM技术的基本原理及工艺特点,重点分析了LAM超高温氧化物陶瓷过程中的孔隙缺陷特征、熔池流动特点及孔隙缺陷的形成机理,并从工艺参数优化、外场辅助和第二相掺杂三个方面详细阐述了LAM超高温氧化物陶瓷孔隙缺陷抑制的研究进展。最后,总结了LAM超高温氧化物陶瓷实现工程化应用面临的挑战,并在成型缺陷抑制、粉末特性和后续热处理工艺等方面展望了该领域的发展趋势和突破点。
基金Supported by "Twelve-five" Scientific Research Study on Education from Chinese Academy of Higher Education(No.11YB032)by Scientific Research Study on Education from Sichuan Academy of Higher Education(No.11SC-007)by Key research project on teaching reform from Chengdu University of Traditional Chinese Medicine(No.JGZD201001)
文摘OBJECTIVE:To assess the effect of case-based learning(CBL)in the education of Traditional Chinese Medicine(TCM).METHODS:The studies concerning TCM courses designed with CBL were included by searching the databases of EBSCO,Pubmed,Science Citation Index,China National Knowledge Infrastructure,Chongqing VIP database.The valid data was extracted in accordance with the included criteria.The quality of the studies was assessed with Gemma Flores-Masteo.RESULTS:A total of 22 articles were retrieved that met the selection criteria:one was of high quality;two were of low quality;the rest were categorized as moderate quality.The majority of the studiesdemonstrated the better effect produced by CBL,while a few studies showed no difference,compared with the didactic format.All included studies confirmed the favorable effect on learners'attitude,skills and ability.CONCLUSION:CBL showed the desirable results in achieving the goal of learning.Compared to didactic approach,it played a more active role in promoting students'competency.Since the quality of the articles on which the study was based was not so high,the findings still need further research to become substantiated.
文摘背景:正畸力通过多种信号通路激活牙周组织自噬,进一步增强或减弱相关细胞(牙周膜细胞、骨细胞、破骨细胞和成骨细胞等)的活性来促进牙周重塑。目的:综述目前正畸力介导牙周组织自噬的研究进展和其对正畸牙齿移动的影响。方法:在PubMed、Web of Science、中国生物医学文献数据库和中国知网数据库进行文献检索,设置检索时限为2010-2023年,总结了2010年以来正畸与自噬相关研究进展,最终纳入76篇文献进行分析讨论。结果与结论:(1)正畸力可通过牙周机械感受器和其造成的无菌性炎症引发一系列生物化学信号的转变,进而引起牙周组织自噬。(2)自噬通过级联放大的信号通路如磷脂酰肌醇-3-激酶/蛋白激酶B通路、河马通路及丝裂原活化蛋白激酶通路等,产生相应反馈从而促进牙周组织改建,最终实现牙齿的移动与稳定。正畸力诱导的自噬可差异性调节牙齿压力侧骨吸收和张力侧骨形成,相关靶点在正畸临床治疗的应用中具有良好前景。(3)然而,正畸力与自噬的机制较为复杂,现有研究仅停留在探究自噬对正畸牙齿移动的作用,自噬与正畸牙齿移动过程中的相互调节作用、涉及相关通路上游机械受体及信号通路间的交互作用均需要进一步的探究。
