A semiconductor device having improved adhesiveness between films composing an interlayer insulating film is presented by providing multilayered films in the interlayer insulating films having film density distribution, in which the film density is gradually changes. The display pixels of the display device may have multiple stable display states and the first data pixels may be generated by a first unit. The oxidized species of the redox couples oxidize the infectious waste molecules and are themselves converted to their reduced form, whereupon they are reoxidized by either of the aforementioned mechanisms and the redox cycle continues until all oxidizable infectious waste species have undergone the desired degree of oxidation. The heat exchanger includes a pair of header pipes connected with both ends of the core.