In this paper we present a new experimental observation using a conventional reflectometry technique,poloidal correlation reflectometry(PCR),in the Experimental Advanced Superconducting Tokamak(EAST).The turbulence sp...In this paper we present a new experimental observation using a conventional reflectometry technique,poloidal correlation reflectometry(PCR),in the Experimental Advanced Superconducting Tokamak(EAST).The turbulence spectrum detected by the PCR system exhibits an asymmetry and induced Doppler shift f_(D)during the internal kink mode(IKM)rotation phase.This Doppler shift f_(D)is the target measurement of Doppler reflectometry,but captured by conventional reflectometry.Results show that the Doppler shift f_(D)is modulated by the periodic changes in the effective angle between the probing wave and cutoff layer normal,but not by plasma turbulence.The fishbone mode and saturated long-lived mode are typical IKMs,and this modulation phenomenon is observed in both cases.Moreover,the value of the Doppler shift f_(D)is positively correlated with the amplitude of the IKM,even when the latter is small.However,the positive and negative frequency components of the Doppler shift f_(D)can be asymmetric,which is related to the plasma configuration.A simulated analysis is performed by ray tracing to verify these observations.These results establish a clear link between f_(D)and IKM rotation,and are helpful for studying the characteristics of IKM and related physical phenomena.展开更多
The local deformation behavior and dynamic recrystallization of a shock compressed Mg-1Zn alloy was investigated through EBSD and TEM.Since dislocation slipping and twinning were locally suppressed during high strain-...The local deformation behavior and dynamic recrystallization of a shock compressed Mg-1Zn alloy was investigated through EBSD and TEM.Since dislocation slipping and twinning were locally suppressed during high strain-rate deformation,a more flexible kinking deformation was activated to adjusted local orientation and facilitate slipping and twinning within the kinks.Meanwhile,due to the slow heat dissipation that resulted in a local temperature elevating,the kink bands were evolved into deformation bands with recrystallized nano-grains.Such a finding provides a new perspective for kinking-facilitated nanocrystallization in Mg alloys and other anisotropic metallic materials.展开更多
目的探讨经桡动脉入路脑血管造影中持续动脉压监测在发现导管扭转打结中的作用。方法回顾性分析2017年7月至2019年12月接受经桡动脉入路脑血管造影的116例缺血性脑血管病患者的临床病例资料,其中80例造影过程中接受持续动脉压监测(测压...目的探讨经桡动脉入路脑血管造影中持续动脉压监测在发现导管扭转打结中的作用。方法回顾性分析2017年7月至2019年12月接受经桡动脉入路脑血管造影的116例缺血性脑血管病患者的临床病例资料,其中80例造影过程中接受持续动脉压监测(测压组),另36例作为无测压组。在操作过程中,动脉压力差变小甚至曲线变平提示导管某段发生扭转打结。比较两组患者的性别、年龄、主动脉弓型等基本临床病例信息,手术适应证、透视时间、手术时间,以及造影过程中导管扭转打结发生率。结果两组患者性别、年龄、主动脉弓型、透视时间、手术时间差异均无统计学意义。测压组动脉导管扭转打结发生率低于无测压组(0 vs 8.33%,P=0.047)。结论持续动脉压力监测有助于发现早期桡动脉入路脑血管造影过程中导管扭转打结,进而降低相关并发症的发生,值得推广应用。展开更多
多晶硅薄膜晶体管(P-Si TFTs)技术在SOP(system on panel)显示应用中发挥着越来越重要的作用。随着尺寸的不断缩小,P-Si TFT的Kink效应越来越明显,对有源液晶显示矩阵和驱动电路的性能影响很大。对发生Kink效应的物理机制、二维数值仿...多晶硅薄膜晶体管(P-Si TFTs)技术在SOP(system on panel)显示应用中发挥着越来越重要的作用。随着尺寸的不断缩小,P-Si TFT的Kink效应越来越明显,对有源液晶显示矩阵和驱动电路的性能影响很大。对发生Kink效应的物理机制、二维数值仿真及其一维解析模型进行了分析,讨论了晶粒边界、沟道长度与Kink效应的关系,提出建立适合电路仿真的一维解析模型的关键与展望。展开更多
A semi-analytical method is introduced to study kink instability in cylindrical plasma with line-tied boundary conditions. The method is based on an expansion for magnetohydrodynamics （MHD） equations in one-dimensio...A semi-analytical method is introduced to study kink instability in cylindrical plasma with line-tied boundary conditions. The method is based on an expansion for magnetohydrodynamics （MHD） equations in one-dimensional （1D） radial eigenvalue problems by using Fourier transforms. The MHD equations then become an ordinary differential equation. This method is applicable to both ideal and non-ideal MHD problem. The effect of plasma pressure （P0） on kink instability is studied in a cylindrical geometry. Complex discrete spectra are pre- sented. Two-dimensional （2D） eigenfunctions with the line-tied boundary conditions are obtained. The growth rate and radial eigenfunctions are different in the two cases of P0 = 0 and P0 ≠ 0, which indicate that the effect of plasma pressure can not be ignored if it is large enough. This method allows us to understand the role of individual radial eigenfunctions, and is also computationally efficient compared to direct solutions of the MHD equations by the finite difference method.展开更多
基金supported by the National Key R&D Program of China(Nos.2022YFE03050003,2022YFE03020004,2019YFE03080200 and 2022YFE03070004)National Natural Science Foundation of China(Nos.12275315,11875289,12175277 and 11975271)+3 种基金partly supported by the Youth Science and Technology Talents Support Program(2020)by Anhui Association for Science and Technology(No.RCTJ202009)the Science Foundation of Institute of Plasma Physics,Chinese Academy of Sciences(No.DSJJ2021-08)the China Postdoctoral Science Foundation(No.2021M703256)the Director Funding of Hefei Institutes of Physical Science,Chinese Academy of Sciences(No.YZJJ2022QN16)。
文摘In this paper we present a new experimental observation using a conventional reflectometry technique,poloidal correlation reflectometry(PCR),in the Experimental Advanced Superconducting Tokamak(EAST).The turbulence spectrum detected by the PCR system exhibits an asymmetry and induced Doppler shift f_(D)during the internal kink mode(IKM)rotation phase.This Doppler shift f_(D)is the target measurement of Doppler reflectometry,but captured by conventional reflectometry.Results show that the Doppler shift f_(D)is modulated by the periodic changes in the effective angle between the probing wave and cutoff layer normal,but not by plasma turbulence.The fishbone mode and saturated long-lived mode are typical IKMs,and this modulation phenomenon is observed in both cases.Moreover,the value of the Doppler shift f_(D)is positively correlated with the amplitude of the IKM,even when the latter is small.However,the positive and negative frequency components of the Doppler shift f_(D)can be asymmetric,which is related to the plasma configuration.A simulated analysis is performed by ray tracing to verify these observations.These results establish a clear link between f_(D)and IKM rotation,and are helpful for studying the characteristics of IKM and related physical phenomena.
基金supported by National Natural Science Foundation of China(No.51701121,No.51825101)Shanghai Sailing Program(No.17YF1408800)+2 种基金Laboratory of Intense Dynamic Loading and Effect Foundation of China(No.IDEL1908)Startup Fund for Youngman Research at SJTU(No.18×100040022)Science and Technology Commission of Shanghai Municipality(No.18511109302).
文摘The local deformation behavior and dynamic recrystallization of a shock compressed Mg-1Zn alloy was investigated through EBSD and TEM.Since dislocation slipping and twinning were locally suppressed during high strain-rate deformation,a more flexible kinking deformation was activated to adjusted local orientation and facilitate slipping and twinning within the kinks.Meanwhile,due to the slow heat dissipation that resulted in a local temperature elevating,the kink bands were evolved into deformation bands with recrystallized nano-grains.Such a finding provides a new perspective for kinking-facilitated nanocrystallization in Mg alloys and other anisotropic metallic materials.
文摘目的探讨经桡动脉入路脑血管造影中持续动脉压监测在发现导管扭转打结中的作用。方法回顾性分析2017年7月至2019年12月接受经桡动脉入路脑血管造影的116例缺血性脑血管病患者的临床病例资料,其中80例造影过程中接受持续动脉压监测(测压组),另36例作为无测压组。在操作过程中,动脉压力差变小甚至曲线变平提示导管某段发生扭转打结。比较两组患者的性别、年龄、主动脉弓型等基本临床病例信息,手术适应证、透视时间、手术时间,以及造影过程中导管扭转打结发生率。结果两组患者性别、年龄、主动脉弓型、透视时间、手术时间差异均无统计学意义。测压组动脉导管扭转打结发生率低于无测压组(0 vs 8.33%,P=0.047)。结论持续动脉压力监测有助于发现早期桡动脉入路脑血管造影过程中导管扭转打结,进而降低相关并发症的发生,值得推广应用。
文摘多晶硅薄膜晶体管(P-Si TFTs)技术在SOP(system on panel)显示应用中发挥着越来越重要的作用。随着尺寸的不断缩小,P-Si TFT的Kink效应越来越明显,对有源液晶显示矩阵和驱动电路的性能影响很大。对发生Kink效应的物理机制、二维数值仿真及其一维解析模型进行了分析,讨论了晶粒边界、沟道长度与Kink效应的关系,提出建立适合电路仿真的一维解析模型的关键与展望。
基金supported by National Basic Research Program of China (No.2008CB717801)National Natural Science Foundation of China (No.10875024)Laboratory of College and University Program of Liaoning Province of China (No.2008S059)
文摘A semi-analytical method is introduced to study kink instability in cylindrical plasma with line-tied boundary conditions. The method is based on an expansion for magnetohydrodynamics （MHD） equations in one-dimensional （1D） radial eigenvalue problems by using Fourier transforms. The MHD equations then become an ordinary differential equation. This method is applicable to both ideal and non-ideal MHD problem. The effect of plasma pressure （P0） on kink instability is studied in a cylindrical geometry. Complex discrete spectra are pre- sented. Two-dimensional （2D） eigenfunctions with the line-tied boundary conditions are obtained. The growth rate and radial eigenfunctions are different in the two cases of P0 = 0 and P0 ≠ 0, which indicate that the effect of plasma pressure can not be ignored if it is large enough. This method allows us to understand the role of individual radial eigenfunctions, and is also computationally efficient compared to direct solutions of the MHD equations by the finite difference method.
