In this paper, a quantitative analysis of the opening quality in friction spinning and its main ef-fecting factors is first made. Upon this basis the Box-Hunter’s experimental design method is usedto establish the qu...In this paper, a quantitative analysis of the opening quality in friction spinning and its main ef-fecting factors is first made. Upon this basis the Box-Hunter’s experimental design method is usedto establish the quadratic regressional equations in terms of primary opening technologicalparameters and yarn quality for medium and fine count friction spinning. The results of analysisand discussion show that the proper choice of opening roller speed and its reasonable match withthe yarn count is singificant for ensuring the spinning quality index as well as reducing unevenness,thin and thick places of the yarn.展开更多
介绍了如何利用场效应管的小信号散射(S)参数设计射频功率放大器,并采用此设计方法,选用场效应管,设计了一种工作在160 MHz频段的金属氧化物半导体场效应管(MOSFET)功率放大器。在工作频段内,功率放大器增益大于23 d B,输入端口的匹配...介绍了如何利用场效应管的小信号散射(S)参数设计射频功率放大器,并采用此设计方法,选用场效应管,设计了一种工作在160 MHz频段的金属氧化物半导体场效应管(MOSFET)功率放大器。在工作频段内,功率放大器增益大于23 d B,输入端口的匹配网络的回波损耗S11优于-19 d B。实例证明:该设计方法仿真简单,易于实现,具有重要的工程应用价值。展开更多
The problem of the creeping flow through a spherical droplet with a non-homogenous porous layer in a spherical container has been studied analytically.Darcy’s model for the flow inside the porous annular region and t...The problem of the creeping flow through a spherical droplet with a non-homogenous porous layer in a spherical container has been studied analytically.Darcy’s model for the flow inside the porous annular region and the Stokes equation for the flow inside the spherical cavity and container are used to analyze the flow.The drag force is exerted on the porous spherical particles enclosing a cavity,and the hydrodynamic permeability of the spherical droplet with a non-homogeneous porous layer is calculated.Emphasis is placed on the spatially varying permeability of a porous medium,which is not covered in all the previous works related to spherical containers.The variation of hydrodynamic permeability and the wall effect with respect to various flow parameters are presented and discussed graphically.The streamlines are presented to discuss the kinematics of the flow.Some previous results for hydrodynamic permeability and drag forces have been verified as special limiting cases.展开更多
文摘In this paper, a quantitative analysis of the opening quality in friction spinning and its main ef-fecting factors is first made. Upon this basis the Box-Hunter’s experimental design method is usedto establish the quadratic regressional equations in terms of primary opening technologicalparameters and yarn quality for medium and fine count friction spinning. The results of analysisand discussion show that the proper choice of opening roller speed and its reasonable match withthe yarn count is singificant for ensuring the spinning quality index as well as reducing unevenness,thin and thick places of the yarn.
文摘介绍了如何利用场效应管的小信号散射(S)参数设计射频功率放大器,并采用此设计方法,选用场效应管,设计了一种工作在160 MHz频段的金属氧化物半导体场效应管(MOSFET)功率放大器。在工作频段内,功率放大器增益大于23 d B,输入端口的匹配网络的回波损耗S11优于-19 d B。实例证明:该设计方法仿真简单,易于实现,具有重要的工程应用价值。
基金Project supported by the Science and Engineering Research Board,New Delhi(No.SR/FTP/MS-47/2012)。
文摘The problem of the creeping flow through a spherical droplet with a non-homogenous porous layer in a spherical container has been studied analytically.Darcy’s model for the flow inside the porous annular region and the Stokes equation for the flow inside the spherical cavity and container are used to analyze the flow.The drag force is exerted on the porous spherical particles enclosing a cavity,and the hydrodynamic permeability of the spherical droplet with a non-homogeneous porous layer is calculated.Emphasis is placed on the spatially varying permeability of a porous medium,which is not covered in all the previous works related to spherical containers.The variation of hydrodynamic permeability and the wall effect with respect to various flow parameters are presented and discussed graphically.The streamlines are presented to discuss the kinematics of the flow.Some previous results for hydrodynamic permeability and drag forces have been verified as special limiting cases.
