Abstract: A method of manufacturing aluminum-substituted hematite represented by ?-(Fe1-xAlx)2O3 where x=0.01 to 0.15, by mixing an iron compound and an aluminum compound such that an atomic ratio of Fe to Al falls within the range of 99:1 to 85:15, adding citric acid and ethylene glycol to the mixture of the iron compound and aluminum compound to produce a gel, and pyrolyzing the gel, followed by calcining the pyrolyzed product.

Abstract: An active common mode canceler includes a voltage detection circuit including a plurality of capacitors connected to the output terminals of a power converter for performing power conversion by switching a power semiconductor device and serving to detect a common mode voltage generated when the power semiconductor device is switched, a push-pull type emitter follower circuit which is controlled by the common mode voltage detected by the voltage detection voltage to output a voltage equal in magnitude and opposite in polarity to the common mode voltage, and a common mode transformer having multiple windings and serving to cancel out the common mode voltage by superimposing the voltage output from the emitter follower circuit on the output from the power converter.