The present invention discloses an in vitro method to identify a contaminant gas in a specimen comprising a mixture of gases as a function of the decay rate of at least one species of positronium. The charge dissipation layer may be located under or over the cathode electrode andor electron field emitter. 1% to 20% by weight of a photo-catalyst, 0. The mold assembly also includes at least one vent hole, at least one bore in communication with the vent hole so that a preselected air pressure is applied to the molten molding material in the cavity via the bore and the vent hole, and at least one exhaust hole adjacent to, but spaced from the vent hole. According to the restraining signal, an output power of the converter is decreased to a predetermined value in real time or the converter is suspended. The device is comprised of the following components.