| 摘要 |
PURPOSE: To evaluate the degree of maturity of a watermelon in a nondestructive manner and quickly by measuring lateral relaxation time of a nucleus of hydrogen in a water molecule contained in watermelon juice. CONSTITUTION: When a watermelon 15 is put in the center of a bore of a main coil 1, that is, in a static magnetic field in the direction of the axis (z), a magnetic field moment of a spin of a nucleus of hydrogen in the juice precesses around an axis parallel to the axis (z). While a gradient magnetic field is impressed 2 in the direction of the axis (z), a selective 90-degree pulse is impressed by a probe coil 3 and a slice area in the direction of the axis (z) is limited. Then only the spin in a specific slice plane intersecting the axis (z) perpendicularly changes direction at an angle of 90 degrees. When a time Te of impression passes after the same operation is executed also in the directions of the axes (x) and (y), an echo signal is obtained. The echo signal observed from outside is only the one from an area wherein three orthogonal slices overlap one another, and by executing slice selection so that this area may coincide with the area wherein the degree of maturity is to be evaluated, evaluation for the specified area can be performed. Accordingly, the area of 10×10×10(mm) is set at various positions in the flesh and lateral relaxation time is measured from the echo signals obtained with the time Te varied.
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