摘要
以HI76303电导电极为例,从电学基本理论出发,研究了电导仪产生边界效应的原因,分析得出电极外部回路是产生边界效应的根本原因。电导仪测定的电导率结果为探头外部和探头内部溶液并联形成的电导率值;通过计算发现,电极敏感区域为直径约8 cm的椭球体。切断电极外部回路是消除边界效应的根本方法。以HI76303电导电极为基础,设计了一种改进型电极,计算表明,改进型电极工作时电势在激励电极之间均匀下降,电极外部溶液电势处处相等且为零,电极内部电流密度处处一致,电极外部电流密度为零。实验数据显示其有效地消除了边界效应。
Taking HI76303 conductance electrode as an example,through theoretical study on the causes of boundary effect of the conductance electrode,it is found that,the current circuit out of the EC probe is the main cause of the boundary effect,and so the measurement is the paralleled conductivity composed by the external and internal solution conductivities of the EC probe.The potential and current density distributions of the EC probe are calculated and the sensitive area is an ellipsoid with a diameter of about 8 cm.The concept of boundary effect is defined as the phenomenon that deviation of the measurements would be caused by changes of diameter of the containers or changes of position or angle the probe was put in the container.A basic method to eliminate boundary effect was to cut off the current circuit out of the EC probe.So an improved EC probe based on the HI76303 conductance electrode is designed.It is found that the value of electric potential was zero out of the improved EC probe and reduced homogeneously between the two exciting electrode;and the current density was evenly distributed between the two exciting electrodes but zero out of the probe.Experimental data showed that the improved EC probe could effectively eliminate boundary effect.
出处
《实验技术与管理》
CAS
北大核心
2011年第7期39-42,46,共5页
Experimental Technology and Management
基金
国家自然科学基金项目(40771097)
公益性行业(农业)科研专项经费项目(200903001)
国家科技支撑项目(2007BAC17B04)
新疆维吾尔自治区科技攻关项目(200733144-1)
关键词
电导电极
边界效应
消除方法
conductance electrode
boundary effect
elimination method
作者简介
刘梅先（1986-），男，江西，博士研究生，主要从事土壤盐渍化及其环境效应研究．E-mail：：mxliu@issas．ac．cn
通信作者：杨劲松（1959-），男，江苏靖江，博士，研究员，研究方向为溶质运移理论及土壤改良．E—mail：jsyang@issas．ac．cn
