Abstract: A solar collector of the non-tracking fluid circulating type which is formed of light weight materials and comprises a frame supporting fluid circulating tubes having a light absorber disposed axially therein and lined with retroreflective cube-corners. The tubes are placed in semicircular reflectors and enclosed by a transparent barrier sheet and cover having light anti-reflective coatings.

Abstract: Composite energy control sheet of the type wherein a transparent-reflective metal layer is coated on a self-supporting transparent polymeric foil and protectively covered with a transparent polymeric layer. The protective polymeric layer is chosen to transmit 80% or more of the normal room temperature radiant energy spectrum (about 4-40 micrometer wavelength) so that when the energy control sheet is positioned adjacent (but other than outside of) a glazing unit and oriented so that the protective layer does not contact any face of the glazing unit, heat loss from the room is significantly decreased and the cold weather performance of the sheet is greatly improved. Among the suitable polymers for the polymeric layer are polyethylene, polypropylene and polyacrylonitrile.

Abstract: Single crystals of zinc oxide which efficiently fluoresce in the near UV due to the radiative recombination of free excitons. Increased efficiency is attributed to treatment of the crystals to optimize the concentration of free excitons by providing donors to compensate an as-grown concentration of acceptors of less than 10 parts per million.

Abstract: A light emitting diode comprising a single crystal of high efficiency violet fluorescing zinc oxide together with an ohmic cathode and a rectifying anode secured thereto. The diode emits near band-gap radiation at room temperature when energized with low D.C. voltage. The produced light is believed to be associated with radiative recombination of free excitons.