| 摘要 |
A viscoelasticity measurement instrument having a support whose position can be varied relative to a sample holder for holding an end portion of a sample. A detection rod is resiliently held to the support, and holds a part of the sample. When a DC or AC force is applied to the detection rod, the displacement of the detection rod relative to the support is detected. The position of the support is varied or the DC force is varied to restore the displacement to zero. In this manner, the effect of the elastic constant of the support is eliminated. In one embodiment, a detection rod is support by leaf springs. Negative feedback control is utilized to return deformation of the leaf springs to zero at all times to eliminate the spring constant effect of the leaf springs. Since the average displacement of the leaf springs is zero, the positional relation between the permanent magnet and the coil forming the electromagnetic force generator varies negligibly. Therefore, the linearity between the current flowing through the coil and the generated force is secured well to enhance the accuracy of the measured viscoelasticity data.
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