Understanding and characterizing rough contact and wavy surfaces are essential for developing effective strategies to mitigate wear,optimize lubrication,and enhance the overall performance and durability of mechanical...Understanding and characterizing rough contact and wavy surfaces are essential for developing effective strategies to mitigate wear,optimize lubrication,and enhance the overall performance and durability of mechanical systems.The sliding friction contact problem between a thermoelectric(TE)half-plane and a rigid solid with a periodic wavy surface is the focus of this investigation.To simplify the problem,we utilize mixed boundary conditions,leading to a set of singular integral equations(SIEs)with the Hilbert kernels.The analytical solutions for the energy flux and electric current density are obtained by the variable transform method in the context of the electric and temperature field.The contact problem for the elastic field is transformed into the second-kind SIE and solved by the Jacobi polynomials.Notably,the smoothness of the wavy contact surface ensures that there are no singularities in the surface contact stress,and ensures that it remains free at the contact edge.Based on the plane strain theory of elasticity,the analysis primarily examines the correlation between the applied load and the effective contact area.The distribution of the normal stress on the surface with or without TE loads is discussed in detail for various friction coefficients.Furthermore,the obtained results indicate that the in-plane stress decreases behind the trailing edge,while it increases ahead of the trailing edge when subjected to TE loads.展开更多
目的了解近20年心电图Tp-Te间期的研究进展,探索当下的研究热点及未来的研究方向。方法在中国期刊全文数据库和Web of Science数据库核心合集中,以“Tp-Te”或“Tp-e”为篇目检索词,检索2002-01-01至2021-12-31这20年间发表的相关文献...目的了解近20年心电图Tp-Te间期的研究进展,探索当下的研究热点及未来的研究方向。方法在中国期刊全文数据库和Web of Science数据库核心合集中,以“Tp-Te”或“Tp-e”为篇目检索词,检索2002-01-01至2021-12-31这20年间发表的相关文献。采用Excel 2019及文献计量分析软件VOSviewer 1.6.17进行文献分类、关键词聚类,并对国家和机构合作及其时序变化等进行可视化分析,绘制相应的图谱。结果从两个数据库中分别获取414篇中文文献和669篇英文文献。相关中文文献数量在2006年以后明显递增,2017年达到峰值,此后发文数量趋于平稳;英文文献在统计时段内共出现2次峰值,分别是2006、2021年,且从2009年起基本呈递增趋势。发文量大的为固定的数种期刊,且发文量相差不大。英文文献国家聚类图中,土耳其虽然发文量多,但是与其他国家的合作并不多;与其他国家合作最多的是美国,其次是中国。发文的各机构间无明显密切合作。关键词聚类分析显示,中文文献以室性心律失常为主的相关研究较多,且在2016年后慢性心力衰竭、急性心肌梗死和急性冠脉综合征等研究主题趋热,对临床用药也有涉及;英文文献涵盖了长QT间期、Tp-e/QT、死亡率、猝死、P波离散度、肥胖以及新型冠状病毒肺炎等。结论我国Tp-Te间期相关的研究热点与其他国家有较大不同,这与国情、生活环境、社会现状及体质差异有关。展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.12262033,12272269,12062021,and 12062022)Ningxia Hui Autonomous Region Science and Technology Innovation Leading Talent Training Project of China(No.2020GKLRLX01)the Natural Science Foundation of Ningxia of China(Nos.2023AAC02003 and 2022AAC03001)。
文摘Understanding and characterizing rough contact and wavy surfaces are essential for developing effective strategies to mitigate wear,optimize lubrication,and enhance the overall performance and durability of mechanical systems.The sliding friction contact problem between a thermoelectric(TE)half-plane and a rigid solid with a periodic wavy surface is the focus of this investigation.To simplify the problem,we utilize mixed boundary conditions,leading to a set of singular integral equations(SIEs)with the Hilbert kernels.The analytical solutions for the energy flux and electric current density are obtained by the variable transform method in the context of the electric and temperature field.The contact problem for the elastic field is transformed into the second-kind SIE and solved by the Jacobi polynomials.Notably,the smoothness of the wavy contact surface ensures that there are no singularities in the surface contact stress,and ensures that it remains free at the contact edge.Based on the plane strain theory of elasticity,the analysis primarily examines the correlation between the applied load and the effective contact area.The distribution of the normal stress on the surface with or without TE loads is discussed in detail for various friction coefficients.Furthermore,the obtained results indicate that the in-plane stress decreases behind the trailing edge,while it increases ahead of the trailing edge when subjected to TE loads.
文摘目的了解近20年心电图Tp-Te间期的研究进展,探索当下的研究热点及未来的研究方向。方法在中国期刊全文数据库和Web of Science数据库核心合集中,以“Tp-Te”或“Tp-e”为篇目检索词,检索2002-01-01至2021-12-31这20年间发表的相关文献。采用Excel 2019及文献计量分析软件VOSviewer 1.6.17进行文献分类、关键词聚类,并对国家和机构合作及其时序变化等进行可视化分析,绘制相应的图谱。结果从两个数据库中分别获取414篇中文文献和669篇英文文献。相关中文文献数量在2006年以后明显递增,2017年达到峰值,此后发文数量趋于平稳;英文文献在统计时段内共出现2次峰值,分别是2006、2021年,且从2009年起基本呈递增趋势。发文量大的为固定的数种期刊,且发文量相差不大。英文文献国家聚类图中,土耳其虽然发文量多,但是与其他国家的合作并不多;与其他国家合作最多的是美国,其次是中国。发文的各机构间无明显密切合作。关键词聚类分析显示,中文文献以室性心律失常为主的相关研究较多,且在2016年后慢性心力衰竭、急性心肌梗死和急性冠脉综合征等研究主题趋热,对临床用药也有涉及;英文文献涵盖了长QT间期、Tp-e/QT、死亡率、猝死、P波离散度、肥胖以及新型冠状病毒肺炎等。结论我国Tp-Te间期相关的研究热点与其他国家有较大不同,这与国情、生活环境、社会现状及体质差异有关。
