Disclosed herein is an apparatus and method for manufacturing an exhaust emission control device, and the exhaust emission control device formed thereby. During the joining operation the punch exerts a high punch force to perform the joining operation and the clamp exerts substantially no clamping force to allow for free material deformation in the joining area. The converter is adapted to generate an output current, comprising an output DC bias current and an output signal current, and to provide a gain adjustment through the variation of the first resistor. Thereby, metal ions are dissolved in a complete ionization state from the non-noble metal body, thereby giving sterilization effect to the water. The method for producing an \u03b1-alumina particle comprises steps of: placing a powdery mixture containing an aluminum salt and a seed crystal under a circumstance at not less than pyrolysis temperature of the aluminum salt, and calcining the resultant. Related apparatus and methods are also described.