Extension of the measurement range of electrical conductivity by time-domain reflectometry (TDR)
Extension of the measurement range of electrical conductivity by time-domain reflectometry (TDR)
复制标题
通过时域反射仪 (TDR) 扩展电导率的测量范围
DOI：
10.5194/hess-1-175-1997
复制
发表时间：
1997
影响因子：
6.3
通讯作者：
D. A. Rose
中科院分区：
文献类型：
--
作者：
M. Mojid;G. Wyseure;D. A. Rose
由TDR传感器侵入的介质的电导率（EC）可以从TDR反射图的阻抗来估计。四类传感器在盐溶液中进行了测试，并将TDR脉冲波的阻抗与溶液的EC相关联。在很宽的电导率范围内，阻抗和EC之间的关系是非线性的，但稳定的。二至四次多项式可以将测量范围扩展到44 dS m-1（相当于NaCl浓度为28 g l-1或0.48 N），并导致比线性关系更好的电导率预测。对于用数据记录器自动测量EC，Giese和Tiemann（1975，Adv. Mol. Rel.过程，7：45-59）可以准确测量低于10 dS m-1的电导率。EC和数据记录器记录之间的多项式关系提供了宽范围内电导率的准确估计。然而，对于手动和自动测量，传感器需要单独校准。特别地，在非线性区域中，传感器之间的差异更大。幸运的是，这种关系足够稳定，可以消除重大误差。
The electrical conductivity (EC) of a medium invaded by TDR sensors can be estimated from the impedance of a TDR reflectogram. Four categories of sensor were tested in salt solutions and the impedances of the TDR pulse wave were correlated to the EC of the solution. The relation between the impedance and EC over a wide range of conductivities is non-linear but stable. Second- to fourth-degree polynomials can extend the measurement range to 44 dS m -1 (equivalent to a NaCl concentration of 28 g l -1 or 0.48 N) and result in better prediction of the conductivities than linear relations. For automatic measurement of EC with a datalogger, the method of Giese and Tiemann (1975, Adv. Mol. Rel. Processes, 7: 45-59) gives accurate measurement of conductivities lower than 10 dS m -1 . Polynomial relations between EC and the datalogger's record provide an accurate estimate of the conductivity over a wide range. However, for both manual and automatic measurements, the sensors need to be calibrated individually. In particular, in the non-linear region, the differences between sensors are larger. Fortunately, the relation is sufficiently stable to eliminate significant error.