Abstract: A display apparatus includes a display element that includes an electrolyte solution layer containing an electrochemical luminescent material; and a voltage applying unit that applies a voltage with a waveform having a gradient for a first period and a flat top for a second period following the first period, to the electrolyte solution layer, so that the electrochemical luminescent material emits light.

Abstract: The high density slave magnetic recording media comprising on a non-magnetic substrate a magnetic recording layer coated with magnetic hexagonal ferrite powder along with a binder component to transfer the digital signals stored on the master magnetic recording media by the magnetic contact duplication process, is characterized in that the perpendicular squareness ratio of the magnetic recording layer is not less than 0.58 and is less than 0.7, center line average roughness Ra is not more than 0.01 .mu.m, and the number of convex projections whose pitches are 10 to 90 .mu.m and whose height is not less than 0.03 .mu.m pp (bottom to top) is not more than 10 per 1 mm of running direction. The slave magnetic recording media permits the functionally enough duplication efficiency of digital signals by the magnetic contact duplication process and can considerably curb the error rate during the reproduction of the duplicated digital signals.