平面叉指电极溶液阻抗的低频三角波测量 .pdfVIP

学兔兔 第37卷 第2期 仪 器 仪 表 学 报 Vo1．37 No．2 2016年2月 Chinese Jouma1 of Scientific Instrument Feb．2016 平面叉指电极溶液阻抗的低频三角波测量 胥善治，王 鹏，董永贵 (清华大学精密仪器系精密测试技术及仪器国家重点实验室 北京 100084) 摘 要：针对低浓度电解质溶液中生物细胞阻抗微弱变化过程的测量问题，研究了一种三角波电压激励结合主元分析(PCA)的 测量方法。用三角波电压信号作为激励，采集单周期响应电流信号构成测量向量，由不同时刻所得测量向量组成测量矩阵， PCA处理后的载荷向量中即包含有溶液阻抗的变化信息。这种信号处理方式对阻抗变化过程的测量结果不依赖于等效阻抗 模型的计算，同时可有效避免等效阻抗计算过程中的噪声问题。对低浓度氯化钾溶液中硅基底金电极、PCB基底铜电极和PCB 基底镀金电极3种平面叉指电极进行了实验分析。实验结果表明，三角波激励结合PCA处理的方法可实现对溶液电导率微弱 变化过程的有效检测。 关键词：溶液阻抗；平面叉指电极；电导率；主元分析 中图分类号：TP212．9 TH701 文献标识码：A 国家标准学科分类代码：460．4020 Measurement of planar-interdigitated electrolyte impedance by triangular waveform voltage at low frequencies Xu Shanzhi，Wang Peng，Dong Yonggui (State Key Laboratory of Precision Measurement Technology and Instruments，Dept．of Precision Instrument， Tsinghua University，Beijing 100084，China) Abstract：In order to measure the minor impedance changing process of biological cell suspensions in low concentrated electrolyte solu— tions，a method of triangular waveform voltage excitation is investigated together with principal component analysis(PCA)．Using the tri— angular waveform voltage as the excitation signal，the response current during one duty cycle is sampled to construct a measurement vec— tor．The measurement matrix is then constructed by measured vectors obtained at different measurements．After processed by PCA，the changing information of the solution impedance is contained in the loading vectors．Measurement results of impedance changing with the proposed signal processing method are independent on the equiv