A method for etching a layer that is to be removed on a substrate, in which a Si1-xGex layer is the layer to be removed, this layer being removed, at least in areas, in gas phase etching with the aid of an etching gas, in particular ClF3. The ring is configured to include a first-side contact surface provided with a linear portion in a cross-section perpendicular to a rotating direction of the ring, and a second-side contact surface provided with a curved portion that is continuous in the cross-section perpendicular to the rotating direction of the ring. At least a part of the operation part is disposed inside a sheet output area of the sheet output part, and the display part is disposed outside the sheet output area. A method for using SMP servers is further provided. In the dropping, a greater amount of liquid crystal material is dropped onto display regions close to ends of the first or second substrate, than onto display regions close to a center of the first or second substrate. They are inhibitors of the protease cathepsin A, and are useful for the treatment of diseases such as atherosclerosis, heart failure, renal diseases, liver diseases or inflammatory diseases, for example.