Abstract: The magnetic recording medium includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder, in which the ferromagnetic powder is an ?-iron oxide powder having an average particle size of 9.0 nm to 20.0 nm, and in the ?-iron oxide powder, a content of particles having a particle size smaller than 8.0 nm is less than 20.0% by mass, a content of particles having a particle size smaller than 6.0 nm is less than 5.0% by mass, and a content of particles having a particle size greater than 25.0 nm is less than 20.0% by mass.

Abstract: The magnetic recording medium includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder, in which the ferromagnetic powder is an ?-iron oxide powder having an average particle size of 9.0 nm to 20.0 nm, and in the ?-iron oxide powder, a content of particles having a particle size smaller than 8.0 nm is less than 20.0% by mass, a content of particles having a particle size smaller than 6.0 nm is less than 5.0% by mass, and a content of particles having a particle size greater than 25.0 nm is less than 20.0% by mass.

Abstract: Disclosed herein is a batch type filter system including a cover provided with a supply pipe for supplying raw liquid and air, a plate having a filter medium support on an upper surface thereof and a filtrate exhaust pipe, said cover being vertically separable from said plate, a plurality of filter medium moving rollers provided on both sides of said cover and said plate, and a sheet-like long filter medium stretched over said rollers and adapted to be moved by a predetermined length per one batch of filtration, said filter medium being temporarily fixedly held between the circumferential portion of said cover and the curcumferential portion of said plate. The improvement in the batch type filter system comprises arcuately curved tension bars provided at such positions where a moving direction of the filter medium is changed and on downstream sides of said filter medium moving rollers, so as to apply a larger tensile force to a central portion of said filter medium than to both edge portions thereof.