| 摘要 |
The invention relates to a method and apparatus for determining a material composition such as the presence of contamination in a soil stratum. By measuring the impedance of the material at various positions such as depths x and x + DELTA x, or times x + DELTA x, determining the conductivity G and the capacitance C from the measured impedances and determining the ratio of the derivatives of the conductivity and the capacitance with respect to time, it is possible to use the ratio of dG(x) and dC(x) as an indicator for the material composition. It is found, surprisingly, that when the presence of contamination in a soil is determined, this ratio is mainly determined by a natural composition of the soil and does not vary greatly for a relatively small distance. Unnatural changes in the ratio dG(x)/dC(x) are therefore an indication for the presence of certain substances such as contaminants. |
