A two-dimensional separation platform of capillary isoelectric focusing(CIEF)-capillary zone electrophoresis(CZE) for proteins was constructed by a microdialysis hollow fiber interface. The interface provided ease of ...A two-dimensional separation platform of capillary isoelectric focusing(CIEF)-capillary zone electrophoresis(CZE) for proteins was constructed by a microdialysis hollow fiber interface. The interface provided ease of fabrication,speed of mass delivering and convenience of column switching. Chrome c was selected to demonstrate the 2D separation systems feasibility and resolving performance. The 2D separation system was found to greatly increase the resolving power and overall peak capacity over those obtained for either dimension alone.展开更多
To tackle the issue of notch frequency and center frequency drift of the L(0,1)mode guided wave in ultra⁃sonic guided wave⁃based stress monitoring of prestressed steel strands,a method using higher⁃order mode plateau ...To tackle the issue of notch frequency and center frequency drift of the L(0,1)mode guided wave in ultra⁃sonic guided wave⁃based stress monitoring of prestressed steel strands,a method using higher⁃order mode plateau fre⁃quencies is adopted.First,the correlation between group velocity peaks and phase velocities at these plateau frequen⁃cies is analyzed.This analysis establishes a quantitative rela⁃tionship between phase velocity and stress in the steel strand,providing a theoretical foundation for stress monitor⁃ing.Then the two⁃dimensional Fourier transform is em⁃ployed to separate wave modes.Dynamic programming techniques are applied in the frequency⁃velocity domain to extract higher⁃order modes.By identifying the group veloc⁃ity peaks of these separated higher⁃order modes,the plateau frequencies of guided waves are determined,enabling indi⁃rect measurement of stress in the steel strand.To validate this method,finite element simulations are conducted under three scenarios.Results show that the higher⁃order modes of transient signals from three different positions can be ac⁃curately extracted,leading to successful cable stress moni⁃toring.This approach effectively circumvents the issue of guided wave frequency drift and improves stress monitoring accuracy.Consequently,it significantly improves the appli⁃cation of ultrasonic guided wave technology in structural health monitoring.展开更多
嫦娥四号低频射电频谱仪(Low Frequency Radio Spectrometer,LFRS)放置在月球背面,观测条件得天独厚。然而,嫦娥四号平台存在约10-15W/(m2·Hz)的强干扰,并且干扰在每道时域数据中存在明显差异,大大削弱了低频射电频谱仪的观测灵敏...嫦娥四号低频射电频谱仪(Low Frequency Radio Spectrometer,LFRS)放置在月球背面,观测条件得天独厚。然而,嫦娥四号平台存在约10-15W/(m2·Hz)的强干扰,并且干扰在每道时域数据中存在明显差异,大大削弱了低频射电频谱仪的观测灵敏度。为此,从两组信号的相关性出发,提出基于CLEAN算法,借助互相关功率谱、傅里叶级数等工具,把低频射电频谱仪天线A,B和C的时域观测数据切分为强相关的CLEAN模型信号和部分相关的残余信号。其中,CLEAN模型信号主要由平台干扰信号和可能的低频强射电爆发组成;残余信号由接收机噪声、未扣除的平台干扰信号和常规低频射电信号组成。将该算法应用到实际数据中,结果表明,嫦娥四号低频射电频谱仪的未积分灵敏度可以提高约8个数量级,达到10-23W/(m2·Hz)。在此基础上,基于对平台干扰信号中确定成分和宽带随机成分的分类处理,借助低频射电爆发信号和平台干扰信号在功率谱上的不同表现,以及常规低频射电天文信号受月球自转调制等信息,将来科学分析工作的重点是进一步处理CLEAN模型信号和残余信号,以发现低频强射电天文爆发信号,对全天区进行粗略的成像。展开更多
文摘A two-dimensional separation platform of capillary isoelectric focusing(CIEF)-capillary zone electrophoresis(CZE) for proteins was constructed by a microdialysis hollow fiber interface. The interface provided ease of fabrication,speed of mass delivering and convenience of column switching. Chrome c was selected to demonstrate the 2D separation systems feasibility and resolving performance. The 2D separation system was found to greatly increase the resolving power and overall peak capacity over those obtained for either dimension alone.
基金The National Natural Science Foundation of China(No.52278303).
文摘To tackle the issue of notch frequency and center frequency drift of the L(0,1)mode guided wave in ultra⁃sonic guided wave⁃based stress monitoring of prestressed steel strands,a method using higher⁃order mode plateau fre⁃quencies is adopted.First,the correlation between group velocity peaks and phase velocities at these plateau frequen⁃cies is analyzed.This analysis establishes a quantitative rela⁃tionship between phase velocity and stress in the steel strand,providing a theoretical foundation for stress monitor⁃ing.Then the two⁃dimensional Fourier transform is em⁃ployed to separate wave modes.Dynamic programming techniques are applied in the frequency⁃velocity domain to extract higher⁃order modes.By identifying the group veloc⁃ity peaks of these separated higher⁃order modes,the plateau frequencies of guided waves are determined,enabling indi⁃rect measurement of stress in the steel strand.To validate this method,finite element simulations are conducted under three scenarios.Results show that the higher⁃order modes of transient signals from three different positions can be ac⁃curately extracted,leading to successful cable stress moni⁃toring.This approach effectively circumvents the issue of guided wave frequency drift and improves stress monitoring accuracy.Consequently,it significantly improves the appli⁃cation of ultrasonic guided wave technology in structural health monitoring.
文摘嫦娥四号低频射电频谱仪(Low Frequency Radio Spectrometer,LFRS)放置在月球背面,观测条件得天独厚。然而,嫦娥四号平台存在约10-15W/(m2·Hz)的强干扰,并且干扰在每道时域数据中存在明显差异,大大削弱了低频射电频谱仪的观测灵敏度。为此,从两组信号的相关性出发,提出基于CLEAN算法,借助互相关功率谱、傅里叶级数等工具,把低频射电频谱仪天线A,B和C的时域观测数据切分为强相关的CLEAN模型信号和部分相关的残余信号。其中,CLEAN模型信号主要由平台干扰信号和可能的低频强射电爆发组成;残余信号由接收机噪声、未扣除的平台干扰信号和常规低频射电信号组成。将该算法应用到实际数据中,结果表明,嫦娥四号低频射电频谱仪的未积分灵敏度可以提高约8个数量级,达到10-23W/(m2·Hz)。在此基础上,基于对平台干扰信号中确定成分和宽带随机成分的分类处理,借助低频射电爆发信号和平台干扰信号在功率谱上的不同表现,以及常规低频射电天文信号受月球自转调制等信息,将来科学分析工作的重点是进一步处理CLEAN模型信号和残余信号,以发现低频强射电天文爆发信号,对全天区进行粗略的成像。
