A stator structure comprises an edgewise coil molded with resin with long ends being exposed, a bus bar connected to both ends of the coil ends, and a pump and injection holes for directly cooling the bus bar. Then, an upper silicon layer in an amorphous state is deposited on the silicon germanium layer. The invention also relates to coagulation protein preparations prepared by the process, and the use of such preparations for the treatment and purification of contaminated water.