In this study, free and forced vibration analysis of nano-composite rotating pressurized microbeam reinforced by carbon nanotubes （CNTs） under magnetic field based on modify couple stress theory （MCST） with temper...In this study, free and forced vibration analysis of nano-composite rotating pressurized microbeam reinforced by carbon nanotubes （CNTs） under magnetic field based on modify couple stress theory （MCST） with temperature-variable material propertiesis presented. Also, the boundary conditions at two ends of nano-composite rotating pressurized microbeam reinforced by CNTs are considered as simply supported. The governing equations are obtained based on the Hamilton＇s principle and then computed these equations by using Navier＇s solution. The magnetic field is inserted in the thickness direction of the nano-composite microbeam. The effects of various parameters such as angular velocity, temperature changes, and pressure between of the inside and outside, the magnetic field, material length scale parameter, and volume fraction of nanocomposite microbeam on the natural frequency and response systemare studied. The results show that with increasing volume fraction of nano-composite microbeam, thickness, material length scale parameter, and magnetic fields, the natural frequency increases. The results of this research can be used for optimization of micro-structures and manufacturing sensors, displacement fluid, and drug delivery.展开更多
Drag force is a key parameter in the numerical modeling of gas-particle flow in circulating fluidized beds. The reliability of current drag force correlations over the regime of fast fluidization has, however, not bee...Drag force is a key parameter in the numerical modeling of gas-particle flow in circulating fluidized beds. The reliability of current drag force correlations over the regime of fast fluidization has, however, not been thoroughly investigated. In this article, a drag force correlation accounting for the clustering effects for Geldart A particles is used to simulate the behaviors typical of fast fluidization, including dynamic evolution of clusters as well as time- averaged axial and lateral voidage profiles. Diverse images of clusters are captured and the time-averaged profiles of voidage are shown to be in quantitative agreement with the present empirical correlation. The results based on different constitutive correlations of drag force show the importance of the choice of drag force in modeling fast-fluidized beds. This drag force correlation, based on a simple averaging assumption, could give some basic insights about the magnitude of the drag reduction.展开更多
With the rapid development of globalization, the whole world interweaves unprecedentedly. The frequent global communication is in desperate need of qualified translators and interpreters which draws great attention an...With the rapid development of globalization, the whole world interweaves unprecedentedly. The frequent global communication is in desperate need of qualified translators and interpreters which draws great attention and invokes discussion about the standard of translation. Is the widely acknowledged criterion—neutral position a possible and necessary regulation to justify professional translators? This essay will illustrate that the interpreters influenced by environment, culture and other factors can’t perform with an absolute neutral position. Furthermore, the creativity of interpreters, who conduct heuristic work instead of algorithmic and reduplicated work, play a pivotal role in qualified work and their long-term development on the basis of Skopos Theory and classical examples, which testifies that it is improper to regard neutral position as a significant standard to evaluate the quality of interpreters.展开更多
The interlayer bonding in two-dimensional(2D)materials is particularly important because it is not only related to their physical and chemical stability but also afects their mechanical,thermal,elec-tronic,optical,and...The interlayer bonding in two-dimensional(2D)materials is particularly important because it is not only related to their physical and chemical stability but also afects their mechanical,thermal,elec-tronic,optical,and other properties.To address this issue,we report the direct characterization of the interlayer bonding in 2D SnSe using contact-resonance atomic force microscopy(CR-AFM)in.this study.Site-specific CR spectroscopy and CR force spectroscopy measurements are performed on both SnSe and its supporting SiO2/Si substrate comparatively.Based on the cantilever and contact mechanic models,the contact stifness and vertical Young's modulus are evaluated in comparison with SiO2/Si as a reference material.The interlayer bonding of SnSe is further analyzed in combination with the semi-analytical model and density functional theory calculations.The direct characteriza-tion of interlayer interactions using this non-destructive methodology of CR-AFM would facilitate a better understanding of the physical and chemical properties of 2D layered materials,specifically for interlayer intercalation and vertical heterostructures.展开更多
基金the Iranian Nanotechnology Development Committee for their financial supportthe University of Kashan (463855/7)
文摘In this study, free and forced vibration analysis of nano-composite rotating pressurized microbeam reinforced by carbon nanotubes （CNTs） under magnetic field based on modify couple stress theory （MCST） with temperature-variable material propertiesis presented. Also, the boundary conditions at two ends of nano-composite rotating pressurized microbeam reinforced by CNTs are considered as simply supported. The governing equations are obtained based on the Hamilton＇s principle and then computed these equations by using Navier＇s solution. The magnetic field is inserted in the thickness direction of the nano-composite microbeam. The effects of various parameters such as angular velocity, temperature changes, and pressure between of the inside and outside, the magnetic field, material length scale parameter, and volume fraction of nanocomposite microbeam on the natural frequency and response systemare studied. The results show that with increasing volume fraction of nano-composite microbeam, thickness, material length scale parameter, and magnetic fields, the natural frequency increases. The results of this research can be used for optimization of micro-structures and manufacturing sensors, displacement fluid, and drug delivery.
基金the National Key Technologies R&D Program (2001BA401A03-10).
文摘Drag force is a key parameter in the numerical modeling of gas-particle flow in circulating fluidized beds. The reliability of current drag force correlations over the regime of fast fluidization has, however, not been thoroughly investigated. In this article, a drag force correlation accounting for the clustering effects for Geldart A particles is used to simulate the behaviors typical of fast fluidization, including dynamic evolution of clusters as well as time- averaged axial and lateral voidage profiles. Diverse images of clusters are captured and the time-averaged profiles of voidage are shown to be in quantitative agreement with the present empirical correlation. The results based on different constitutive correlations of drag force show the importance of the choice of drag force in modeling fast-fluidized beds. This drag force correlation, based on a simple averaging assumption, could give some basic insights about the magnitude of the drag reduction.
文摘With the rapid development of globalization, the whole world interweaves unprecedentedly. The frequent global communication is in desperate need of qualified translators and interpreters which draws great attention and invokes discussion about the standard of translation. Is the widely acknowledged criterion—neutral position a possible and necessary regulation to justify professional translators? This essay will illustrate that the interpreters influenced by environment, culture and other factors can’t perform with an absolute neutral position. Furthermore, the creativity of interpreters, who conduct heuristic work instead of algorithmic and reduplicated work, play a pivotal role in qualified work and their long-term development on the basis of Skopos Theory and classical examples, which testifies that it is improper to regard neutral position as a significant standard to evaluate the quality of interpreters.
基金This project was supported by the Min-istry of Science and Technology(MOST)of China(Grant Nos.2016YFA0200700 and 2018YFE0202700)the National Natural Science Foundation of China(NSFC)(Grant Nos.21622304,61674045,11604063,11622437,11974422,61911540074,11804247,and 61674171)+2 种基金Strategic Priority Research Program,Key Research Program of Frontier Sciences,and Instrument Developing Project of Chinese Academy of Sciences(CAS)(Grant Nos.XDB000000,QYZDB-SSW-8Y5031,and YZ201418)Z.H.Cheng was supportod by Distinguished Technical Talents Project and Youth Innovation Promotion Association CAS,Fundamental Research Funds for the Central Universities,and Research Funds of Renmin University of China(Grant Nos.18XNLG01 and 19XNQ025)Calculations were performed at the Physics Lab of High-Performance Computing of Renmin University of China and Shanghal Supercomputer Center.
文摘The interlayer bonding in two-dimensional(2D)materials is particularly important because it is not only related to their physical and chemical stability but also afects their mechanical,thermal,elec-tronic,optical,and other properties.To address this issue,we report the direct characterization of the interlayer bonding in 2D SnSe using contact-resonance atomic force microscopy(CR-AFM)in.this study.Site-specific CR spectroscopy and CR force spectroscopy measurements are performed on both SnSe and its supporting SiO2/Si substrate comparatively.Based on the cantilever and contact mechanic models,the contact stifness and vertical Young's modulus are evaluated in comparison with SiO2/Si as a reference material.The interlayer bonding of SnSe is further analyzed in combination with the semi-analytical model and density functional theory calculations.The direct characteriza-tion of interlayer interactions using this non-destructive methodology of CR-AFM would facilitate a better understanding of the physical and chemical properties of 2D layered materials,specifically for interlayer intercalation and vertical heterostructures.
