The measurement principle is that a load measurement sensor measures the repulsive force and an attractive force generated respectively, by making the permanent magnet close to and distant from a cooled superconductor 8, and the critical current density is evaluated from the loadingcharacterization of the repulsive force in the measured results. 測定原理は、冷却した超伝導体8に永久磁石を近づけることによる斥力と、遠ざけていく時に生じる引力を荷重測定センサーで測定し、その内の斥力の荷重特性から臨界電流密度の評価を行う。 - 特許庁