A key structure including at least two protruding keys and a key frame is provided. The method includes measuring a temperature of the ice maker and determining a first derivative of the temperature of the ice maker with respect to time. Wobble signal amplitude and the maximum amplitude are calculated according to the read data. The fuel cell andor afterburner andor reformer may be arranged downstream of a purification system for the internal-combustion engine exhaust gases and may be essentially inside a pipe or the like carrying the latter. A latch section projects toward the display section retracted in said display apparatus body in accordance with the movement of said sliding structure. The method comprises performing an electroplating process using an electroplating bath containing an aqueous solution which includes a perrhenate ion and a chromium ion.