Deborah Wilson,加拿大著名玉雕、雕塑艺术家。她于1973年就读加拿大温哥华艺术学院(Vancouver School of Art,现已更名为艾米丽卡尔艺术与设计大学Emily Carr University of Art&Design)雕塑专业。大四时期就已经开始了艺术生涯,...Deborah Wilson,加拿大著名玉雕、雕塑艺术家。她于1973年就读加拿大温哥华艺术学院(Vancouver School of Art,现已更名为艾米丽卡尔艺术与设计大学Emily Carr University of Art&Design)雕塑专业。大四时期就已经开始了艺术生涯,作为业余时间的工作。她的作品以大型雕塑为主,包括人像、动物和城市环艺设计等。她的作品古朴、大气,多使用加拿大碧玉创作,具有非常明显的个人风格,在美洲地区深受同行和艺术爱好者的喜爱。展开更多
The flow and heat transfer characteristics of Maxwell fluid in a pipe under pulsating pressure gradient were studied. The governing equations were made dimensionless. The Rubin boundary condition was adopted. The flow...The flow and heat transfer characteristics of Maxwell fluid in a pipe under pulsating pressure gradient were studied. The governing equations were made dimensionless. The Rubin boundary condition was adopted. The flow field was solved theoretically and the temperature field was obtained using finite volume method. A general model suitable for various fluctuating characteristics and physical parameters was established. The Deborah number(De) was used to characterize the fluidity of the fluid. The influence of De on flow and temperature fields was evaluated. The Nusselt number and start-up process of Maxwell fluid were studied. Results showed that the influence of De on flow field was greater than that on temperature field. The effect of De on Nusselt number was irregular and related to the oscillation parameters. The over-shooting amplitude and oscillation time of axis center velocity in start-up flow grow larger with De.展开更多
In this study, the effects of the non-Newtonian rheological properties of the lubricant in a thin-film lubrication regime between smooth surfaces were investigated. The thin-film lubrication regime typically appears i...In this study, the effects of the non-Newtonian rheological properties of the lubricant in a thin-film lubrication regime between smooth surfaces were investigated. The thin-film lubrication regime typically appears in Stribeck curves with a clearly observable minimum coefficient of friction （COF） and a low-COF region, which is desired for its lower energy dissipation. A dynamic rheology of the lubricant from the hydrodynamic lubrication regime to the thin-film lubrication regime was proposed based on the convected Maxwell constitutive equation. This rheology model includes the increased relaxation time and the yield stress of the confined lubricant thin film, as well as their dependences on the lubricant film thickness. The Deborah number （De number） was adopted to describe the liquid-solid transition of the confined lubricant thin film under shearing. Then a series of Stribeck curves were calculated based on Tichy＇s extended lubrication equations with a perturbation of the De number. The results show that the minimum COF points in the Stribeck curve correspond to a critical De number of 1.0, indicating a liquid-to-solid transition of the confined lubricant film. Furthermore, the two proposed parameters in the dynamic rheological model, namely negative slipping length b （indicating the lubricant interracial effect） and the characteristic relaxation time λ0, were found to determine the minimum COF and the width of the low-COF region, both of which were required to optimize the shape of the Stribeck curve. The developed dynamic theological model interprets the correlation between the rheological and interfacial properties of lubricant and its lubrication behavior in the thin-film regime.展开更多
四十五、十佳名字英美人的名字跟中国人的名字有一点是相同的:每个时期有每个时期常见的名字。在 David Crystal 主编的《剑桥英语百科词典》里,介绍了本世纪英美各个不同时期的10个最常见的名字,每个出生的孩子十有三四用的是这些名字...四十五、十佳名字英美人的名字跟中国人的名字有一点是相同的:每个时期有每个时期常见的名字。在 David Crystal 主编的《剑桥英语百科词典》里,介绍了本世纪英美各个不同时期的10个最常见的名字,每个出生的孩子十有三四用的是这些名字,大家不妨一读。在1900年的英国,最常见的10个男子名字依次为:William、John、George、James、Ronald、Robert、Kenneth、Frederick、Thomas、Albert;在美国则为 John、William、Charles、Robert、Joseph、James、George、展开更多
文摘Deborah Wilson,加拿大著名玉雕、雕塑艺术家。她于1973年就读加拿大温哥华艺术学院(Vancouver School of Art,现已更名为艾米丽卡尔艺术与设计大学Emily Carr University of Art&Design)雕塑专业。大四时期就已经开始了艺术生涯,作为业余时间的工作。她的作品以大型雕塑为主,包括人像、动物和城市环艺设计等。她的作品古朴、大气,多使用加拿大碧玉创作,具有非常明显的个人风格,在美洲地区深受同行和艺术爱好者的喜爱。
基金sponsored by China National Key Research and Development Program via Project No.2018YFB0605105。
文摘The flow and heat transfer characteristics of Maxwell fluid in a pipe under pulsating pressure gradient were studied. The governing equations were made dimensionless. The Rubin boundary condition was adopted. The flow field was solved theoretically and the temperature field was obtained using finite volume method. A general model suitable for various fluctuating characteristics and physical parameters was established. The Deborah number(De) was used to characterize the fluidity of the fluid. The influence of De on flow and temperature fields was evaluated. The Nusselt number and start-up process of Maxwell fluid were studied. Results showed that the influence of De on flow field was greater than that on temperature field. The effect of De on Nusselt number was irregular and related to the oscillation parameters. The over-shooting amplitude and oscillation time of axis center velocity in start-up flow grow larger with De.
基金Project sponsored by the National Basic Research Program of China (Grant No. 2012CB934101)the National Natural Science Foundation of China (Grant Nos. 50975154 and 51175282)
文摘In this study, the effects of the non-Newtonian rheological properties of the lubricant in a thin-film lubrication regime between smooth surfaces were investigated. The thin-film lubrication regime typically appears in Stribeck curves with a clearly observable minimum coefficient of friction （COF） and a low-COF region, which is desired for its lower energy dissipation. A dynamic rheology of the lubricant from the hydrodynamic lubrication regime to the thin-film lubrication regime was proposed based on the convected Maxwell constitutive equation. This rheology model includes the increased relaxation time and the yield stress of the confined lubricant thin film, as well as their dependences on the lubricant film thickness. The Deborah number （De number） was adopted to describe the liquid-solid transition of the confined lubricant thin film under shearing. Then a series of Stribeck curves were calculated based on Tichy＇s extended lubrication equations with a perturbation of the De number. The results show that the minimum COF points in the Stribeck curve correspond to a critical De number of 1.0, indicating a liquid-to-solid transition of the confined lubricant film. Furthermore, the two proposed parameters in the dynamic rheological model, namely negative slipping length b （indicating the lubricant interracial effect） and the characteristic relaxation time λ0, were found to determine the minimum COF and the width of the low-COF region, both of which were required to optimize the shape of the Stribeck curve. The developed dynamic theological model interprets the correlation between the rheological and interfacial properties of lubricant and its lubrication behavior in the thin-film regime.
文摘四十五、十佳名字英美人的名字跟中国人的名字有一点是相同的:每个时期有每个时期常见的名字。在 David Crystal 主编的《剑桥英语百科词典》里,介绍了本世纪英美各个不同时期的10个最常见的名字,每个出生的孩子十有三四用的是这些名字,大家不妨一读。在1900年的英国,最常见的10个男子名字依次为:William、John、George、James、Ronald、Robert、Kenneth、Frederick、Thomas、Albert;在美国则为 John、William、Charles、Robert、Joseph、James、George、
