Abstract: For recovering silver and discharging depolluted wastes from washing baths for photographic and like films or papers, a method is disclosed which consists in having the washing liquid running in countercurrent relationship in a number of serially arranged tubs, relative to the direction of advance of the photographic material being washed.The concentration of silver salts is thus increased in a direction contrary to that of advance of the sensitive materials being processed so that the first tub of the series (considered in the machine direction) has such a concentration of silver that the recovery by any methods is economically interesting.

Abstract: A method of manufacturing a semiconductor device, in particular a monolithic integrated circuit having very small complementary transistors. According to the invention two surface zones are provided beside each other without a masking tolerance of which one is formed by diffusion from a thin silicon layer. The distance between the surface zones is determined by the width of an oxide strip formed on the surface and on the edge of the silicon layer. The oxide strip is obtained by an underetching process and by using a silicon nitride mask deposited with shadow effect.

Abstract: A method of producing light emitting diodes of high quantum efficiency in mass production by utilizing an epitaxial deposition from a small size melt such that the substrate itself serves as a saturation source. A silicon doped gallium arsenide wafer is cleaned and etched by normal means and subsequently the wafer is precoated with a properly doped gallium master melt. The coated wafers are inserted into an epitaxial furnace and the gallium master melt effects solution of a portion of the gallium arsenide monocrystal substrate and finally the entire wafer is cooled, maintaining a temperature gradient causing epitaxial growth on the substrate.