| 摘要 |
PURPOSE:To measure quantitatively so far as a transformation rate distribution for a thickness direction by arranging respectively an exciting coil and a detecting coil at the same side of the material to be measured, passing a current of variable frequency to the exciting coil, and obtaining a magnetic permeability of the measuring material for the thickness direction from both coils in each frequency. CONSTITUTION:The exciting coil 12 and the detecting coil 14 are arranged respectively at the same side of a material 10 of the measuring material, currents I1, I2 of the coils 12 and 14 are measured respectively while varying a frequency omega of the current passed through the coil 12. A mutual inductance L(omega) is obtained from the currents I1, I2 of the coils 12, 14 respectively, and the average permeability is calculated by an equation. mu(C.omega1/3) is obtained by using the equation from this average permeability. If mu(C.omega1/3) is plotted by denoting C.omega1/3 as the reference, the variation characteristic of the permeability at the position corresponding to the depth C.omega1/3 is obtained. The transformation rate for the thickness direction is obtained from the variation characteristic of the obtained permeability. |
