Abstract: A DC-AC electric potential treatment apparatus of the present invention can freely switch high potential AC and high potential DC. The DC-AC electric potential treatment apparatus comprises an electric cloth having a treatment lead for outputting high potential AC or high potential DC, a DC-AC power supply circuit for supplying high potential DC and high potential AC to the treatment lead, and a DC-AC switch circuit for switching the supply from the DC-AC power supply circuit to the treatment lead between high potential DC and high potential AC.

Abstract: The invention proposes a device using friction in a liquid medium having a support, notably metallic, on which an interface surface forms a support for a friction lining, with a flat annular shape overall, produced from a friction material which has a porous structure with communicating cells and which has areas (M1, M2, M3) with different controlled porosities. The method of manufacturing the friction lining including a step of moulding under pressure, whilst the interface surface of the support has at least one groove in which there extends the friction material moulded under pressure in order to constitute an area of controlled porosity (M1, M2) greater than the mean porosity (M2, M3) of the body made from friction material constituting the lining.