A method of coating pigment particles is described for preventing degradation and discoloration by ultraviolet light. The chemical species utilized serve as recombination sites for the electrons and holes produced by the radiation. The chemical species selected for a particular pigment should be one equivalent such that stable oxidation stages are formed differing by one electronic charge. Zinc oxide pigments coated with ferri- and ferrocyanide are discussed as an example. *Patent rights in the United States are held by Stanford Research Institute. Foreign patent rights are available for licensing from NASA. A stored charge device of the general type designated as an MNOS field-effect transistor, has its operation improved by embedding a thin metal layer between two insulating films used in the transistor. The embedded metal layer technique is also used to provide a two-terminal thin-film stored charge device, consisting of a "metalinsulator-embedded metal-insulator-metal", sandwich structure which can be used in high-density memory arrays. GRADED BANDGAP AlxGa1-xAs-GaAs SOLAR CELL NASA Case No. LAR-11174 Canada, France, Japan, Address inquiries to: Hampton, VA 23665 [Corresponding U.S. Patent Application Pending] This invention describes an improved solar cell of increased efficiency. The invention comprises a p-type GaAs crystal adjoining an n-type Gaj-x Aly As crystal to form a p-n junction. The value of x varies linearly in the n-type crystal from x-0 at the junction of the two crystals to x = .7 at the opposite surface of the n-type crystal. Hence, when the said opposite surface of the n-type crystal is exposed to solar radiation, energy is delivered by the p-n junction more efficiently than it is delivered by prior p-n junction type solar cells. This invention relates to a method for welding thin sheet metal members by the simultaneous bonding and shaping into an essentially planar configuration without the addition of a bonding material. This is accomplished by explosively welding overlapped sheets while simultaneously bending them such that the major portions of the two sheets are left in a single plane. The method furnishes a simple and economical method of welding thin sheet aluminum and titanium with bonds which exhibit the strength of the parent metal. 10 16 21 IMPROVED NARROW BAND FM SYSTEM FOR NASA Case No. GSC-11261-1 Canada, Great Britain, France, Address inquiries to: Goddard Space Flight Center Attn: Patent Counsel Mail Code: 204 Greenbelt, MD 20771 [Corresponding U.S. Patent-Application Pending] The Narrow Band FM transmitter transmits voice signals on a FM carrier signal. The transmitter includes preemphasis for flattening the frequency spectrum. The receiver includes a demodulator for demodulating the FM carrier with decreasing band width as a function of the carrier strength. Limiting means are employed for decreasing the carrier strength as the incoming carrier-to-noise ratio decreases and a deemphasis circuit for restoring the frequency spectrum of the original voice signal. |