The aim of this study is to numerically investigate the impact of boundary slip on electroosmotic flow(EOF) in curved rectangular microchannels. Navier slip boundary conditions were employed at the curved microchannel...The aim of this study is to numerically investigate the impact of boundary slip on electroosmotic flow(EOF) in curved rectangular microchannels. Navier slip boundary conditions were employed at the curved microchannel walls. The electric potential distribution was governed by the Poisson–Boltzmann equation, whereas the velocity distribution was determined by the Navier–Stokes equation. The finite-difference method was employed to solve these two equations. The detailed discussion focuses on the impact of the curvature ratio, electrokinetic width, aspect ratio and slip length on the velocity. The results indicate that the present problem is strongly dependent on these parameters. The results demonstrate that by varying the dimensionless slip length from 0.001 to 0.01 while maintaining a curvature ratio of 0.5 there is a twofold increase in the maximum velocity. Moreover, this increase becomes more pronounced at higher curvature ratios. In addition, the velocity difference between the inner and outer radial regions increases with increasing slip length. Therefore, the incorporation of the slip boundary condition results in an augmented velocity and a more non-uniform velocity distribution. The findings presented here offer valuable insights into the design and optimization of EOF performance in curved hydrophobic microchannels featuring rectangular cross-sections.展开更多
Experimental results of new type joints between the column and the. steel beam of concrete-filled rectangular steel tubular （CFRT） under reversed cyclic loads are presented. The earthquake resistant capacity of the ...Experimental results of new type joints between the column and the. steel beam of concrete-filled rectangular steel tubular （CFRT） under reversed cyclic loads are presented. The earthquake resistant capacity of the joint is influenced by infilled concrete, stiffener length and relative dimensions of column and beam. It is found that the hysteresis curves obtained in the experiment are full and the joints have a good energy dissipation capacity. The nonlinear finite element models are also used to analyze the hysteresis behavior of the joints under reversed cyclic loads using ANSYS 8.0. The influences of the stiffener length and the infilled concrete are analyzed. Analytical results show that the stiffener length and the infilled concrete are critical for the joints. Furthermore, the skeleton curves of the finite element models are in good agreement with those of experiments.展开更多
The two-phase detection method for directional discrimination in laser Doppler measurements is discussed.The diffraction efficiency of a sin- gle period rectangular phase grating is analysed and a kind of back-scatter...The two-phase detection method for directional discrimination in laser Doppler measurements is discussed.The diffraction efficiency of a sin- gle period rectangular phase grating is analysed and a kind of back-scattered laser Doppler vibrometer without directional ambiguity using the single peri- od rectangular phase grating as the beam-combiner described.The principles of this kind of vibrometer are explained in detail,and some experimental re- sults are given.In this kind of vibrometer,the rectangular phase grating, without the zero diffracted order and even orders,is used to eliminate use- less stray light and to combine the useful signal light.Differential electronics is employed to reject signal noise.Therefore,the signal-to-noise ratio of Doppler signals and the measurement accuracy of the instrument are im- proved and the range of application is expanded.展开更多
运用辛叠加方法求出相邻两边固支其他两边自由(two adjacent edges clamped and the other edges free, CCFF)正交各向异性矩形薄板屈曲问题的级数展开解。首先,将原屈曲问题的控制方程转化为哈密顿系统,通过分析边界条件,将原屈曲问题...运用辛叠加方法求出相邻两边固支其他两边自由(two adjacent edges clamped and the other edges free, CCFF)正交各向异性矩形薄板屈曲问题的级数展开解。首先,将原屈曲问题的控制方程转化为哈密顿系统,通过分析边界条件,将原屈曲问题分解为两个子屈曲问题,再利用辛本征函数展开法分别求得两个子屈曲问题的通解;然后,利用叠加方法得到原屈曲问题的辛叠加解;最后,应用所得辛叠加解分别计算了单/双向载荷作用下的CCFF各向同性和正交各向异性矩形薄板的屈曲问题。计算结果表明,所得辛叠加解是正确的并且其收敛速度较快。展开更多
针对煤矿矩形巷道支护参数设计问题,采用模糊数学对煤巷围岩稳定性的类别进行分析。选择顶板岩石单轴抗压强度、底板岩石单轴抗压强度、煤层单轴抗压强度、巷道埋深、采动影响系数、护巷煤柱宽度、围岩完整程度7个指标作为矩形巷道围岩...针对煤矿矩形巷道支护参数设计问题,采用模糊数学对煤巷围岩稳定性的类别进行分析。选择顶板岩石单轴抗压强度、底板岩石单轴抗压强度、煤层单轴抗压强度、巷道埋深、采动影响系数、护巷煤柱宽度、围岩完整程度7个指标作为矩形巷道围岩稳定性分析指标,并根据不同的围岩稳定性类型选用不同的支护形式;采用(内嵌数值模拟软件优化、CAD)支护设计方法进行设计,并进行合理的支护参数计算,通过数据库中的诸多样本判断类似的样本数据以自动选择合理的支护方案。以Visual Studio 2022为开发工具,利用SQL Sever 2019构建了围岩力学参数、支护参数、围岩稳定性等信息巷道信息数据库,采用C#语言进行计算机编程,实现了巷道参数数据库管理、围岩稳定性分类、支护参数智能设计等功能。展开更多
The cavity-mode resonance effect could result in significant degradation of the shielding effectiveness （SE） of a shielding enclosure around its resonance frequencies. In this paper, the influence of coated wall los...The cavity-mode resonance effect could result in significant degradation of the shielding effectiveness （SE） of a shielding enclosure around its resonance frequencies. In this paper, the influence of coated wall loss on the suppression of the resonance effect is investigated. For this purpose, an equivalent circuit model is employed to analyze the SE of an apertured rectangular cavity coated with an inside layer of resistive material. The model is developed by extending Robinson＇s equivalent circuit model through incorporating the effect of the wall loss into both the propagation constant and the characteristic impedance of the waveguide. Calculation results show that the wall loss could lead to great improvement on the SE for frequencies near the resonance but almost no effect on the SE for frequencies far away from the resonance.展开更多
基金Project supported by the Natural Science Foundation of Inner Mongolia of China(Grant No.2021BS01008)the Program for Innovative Research Team in Universities of Inner Mongolia Autonomous Region(Grant No.NMGIRT2323)the Scientific Research Funding Project for introduced high level talents of IMNU(Grant No.2020YJRC014)。
文摘The aim of this study is to numerically investigate the impact of boundary slip on electroosmotic flow(EOF) in curved rectangular microchannels. Navier slip boundary conditions were employed at the curved microchannel walls. The electric potential distribution was governed by the Poisson–Boltzmann equation, whereas the velocity distribution was determined by the Navier–Stokes equation. The finite-difference method was employed to solve these two equations. The detailed discussion focuses on the impact of the curvature ratio, electrokinetic width, aspect ratio and slip length on the velocity. The results indicate that the present problem is strongly dependent on these parameters. The results demonstrate that by varying the dimensionless slip length from 0.001 to 0.01 while maintaining a curvature ratio of 0.5 there is a twofold increase in the maximum velocity. Moreover, this increase becomes more pronounced at higher curvature ratios. In addition, the velocity difference between the inner and outer radial regions increases with increasing slip length. Therefore, the incorporation of the slip boundary condition results in an augmented velocity and a more non-uniform velocity distribution. The findings presented here offer valuable insights into the design and optimization of EOF performance in curved hydrophobic microchannels featuring rectangular cross-sections.
基金Supprorted by the Science and Technology Foundation of Jiangsu Construction Committee(JS200214)the Science Research Foundation of Nanjing Institute of Technology(KXJ08122)~~
文摘Experimental results of new type joints between the column and the. steel beam of concrete-filled rectangular steel tubular （CFRT） under reversed cyclic loads are presented. The earthquake resistant capacity of the joint is influenced by infilled concrete, stiffener length and relative dimensions of column and beam. It is found that the hysteresis curves obtained in the experiment are full and the joints have a good energy dissipation capacity. The nonlinear finite element models are also used to analyze the hysteresis behavior of the joints under reversed cyclic loads using ANSYS 8.0. The influences of the stiffener length and the infilled concrete are analyzed. Analytical results show that the stiffener length and the infilled concrete are critical for the joints. Furthermore, the skeleton curves of the finite element models are in good agreement with those of experiments.
文摘The two-phase detection method for directional discrimination in laser Doppler measurements is discussed.The diffraction efficiency of a sin- gle period rectangular phase grating is analysed and a kind of back-scattered laser Doppler vibrometer without directional ambiguity using the single peri- od rectangular phase grating as the beam-combiner described.The principles of this kind of vibrometer are explained in detail,and some experimental re- sults are given.In this kind of vibrometer,the rectangular phase grating, without the zero diffracted order and even orders,is used to eliminate use- less stray light and to combine the useful signal light.Differential electronics is employed to reject signal noise.Therefore,the signal-to-noise ratio of Doppler signals and the measurement accuracy of the instrument are im- proved and the range of application is expanded.
文摘运用辛叠加方法求出相邻两边固支其他两边自由(two adjacent edges clamped and the other edges free, CCFF)正交各向异性矩形薄板屈曲问题的级数展开解。首先,将原屈曲问题的控制方程转化为哈密顿系统,通过分析边界条件,将原屈曲问题分解为两个子屈曲问题,再利用辛本征函数展开法分别求得两个子屈曲问题的通解;然后,利用叠加方法得到原屈曲问题的辛叠加解;最后,应用所得辛叠加解分别计算了单/双向载荷作用下的CCFF各向同性和正交各向异性矩形薄板的屈曲问题。计算结果表明,所得辛叠加解是正确的并且其收敛速度较快。
文摘针对煤矿矩形巷道支护参数设计问题,采用模糊数学对煤巷围岩稳定性的类别进行分析。选择顶板岩石单轴抗压强度、底板岩石单轴抗压强度、煤层单轴抗压强度、巷道埋深、采动影响系数、护巷煤柱宽度、围岩完整程度7个指标作为矩形巷道围岩稳定性分析指标,并根据不同的围岩稳定性类型选用不同的支护形式;采用(内嵌数值模拟软件优化、CAD)支护设计方法进行设计,并进行合理的支护参数计算,通过数据库中的诸多样本判断类似的样本数据以自动选择合理的支护方案。以Visual Studio 2022为开发工具,利用SQL Sever 2019构建了围岩力学参数、支护参数、围岩稳定性等信息巷道信息数据库,采用C#语言进行计算机编程,实现了巷道参数数据库管理、围岩稳定性分类、支护参数智能设计等功能。
基金supported by the National Natural Science Foundation of China(Grant No.51037001)
文摘The cavity-mode resonance effect could result in significant degradation of the shielding effectiveness （SE） of a shielding enclosure around its resonance frequencies. In this paper, the influence of coated wall loss on the suppression of the resonance effect is investigated. For this purpose, an equivalent circuit model is employed to analyze the SE of an apertured rectangular cavity coated with an inside layer of resistive material. The model is developed by extending Robinson＇s equivalent circuit model through incorporating the effect of the wall loss into both the propagation constant and the characteristic impedance of the waveguide. Calculation results show that the wall loss could lead to great improvement on the SE for frequencies near the resonance but almost no effect on the SE for frequencies far away from the resonance.
