Masking selected portions of a ribbon and forming an inter-metallic compounds on the unmasked portions by a controlled diffusion reaction produces a twisted filamentary structure. The masking material prohibits the formation of superconductive material on predetermined areas of the substrate. DUALLY MODE-LOCKED Nd:YAG LASER NASA Case No. GSC-11746-1 Canada, France, Germany, Address inquiries to: Goddard Space Flight Center Attn: Patent Counsel Mail Code: 204 Greenbelt, MD 20771 [Corresponding to U.S. Patent No. 3,869,680] A need exists in laser technology whereby stable mode-locking can be achieved for a pulsed laser system which is simple and which avoids other known disadvantages. The present invention meets these requirements and includes a pair of partially reflecting mirrors forming the laser cavity. The dual mode-locking elements will pass timed pulses without being extinguished. DISH ANTENNA HAVING SWITCHABLE BEAMWIDTH NASA Case No. GSC-11760-1 Canada, France, Germany, Address inquiries to: Goddard Space Flight Center Mail Code: 204 Greenbelt, MD 20771 [Corresponding to U.S. Patent No. 3,866,233] The need frequently arises to augment narrow beamwidth transmitting and/or receiving antennas with a wide beamwidth "acquisition" mode. The present invention is a switchable beam width antenna employing a common main reflecting dish operable in at least two different beamwidth modes. It includes a concave parabolic main reflecting dish with a central circular region and a surrounding coaxial annular region. The central region of the main dish can be excited for wide beamwidth or the entire dish for narrow beamwidth. Conventional digital computers are composed of devices which perform logical operations on one-dimensional electrical binary signals. Such conventional digital computers are used to process large two-dimensional image or array data only with great difficulty since, in general, point-by-point scanning or interrogation of the images or arrays is required to convert the image data to a serial data stream suitable for digital computer processing. In this invention two-dimensional radiant energy gate devices receive two input arrays and provide an output array having digital states dependent only on the digital states of the signal elements of the two input arrays at corresponding row and column positions. The logic devices include an array of photoconductors responsive to at least one of the input arrays for either selectively accelerating electrons to a phosphor output surface, applying potentials to an electroluminescent output layer, exciting an array of discrete radiant energy sources, or exciting a liquid crystal to influence crystal transparency or refectivity. ELECTROSTATICALLY CONTROLLED HEAT SHUTTER NASA CASE No. NPO-11942 Australia, Canada, France, Address inquiries to: [Corresponding to U.S. Patent No. 3,763, 928] A heat transfer assembly for conducting thermal energy includes a hermetically sealed container enclosing a quantity of inert gas such as nitrogen. Two opposed walls of the container have high thermal conducting characteristics while the connecting walls have low thermal conducting characteristics. Electrodes are positioned adjacent the high thermal conducting walls and biased relative to the conducting walls to a corona potential for creating an ionic gas wind which must contact the conducting walls to be neutralized. The contact of the gas molecules permits the maximum thermal energy transfer between the walls. Baffles can be positioned adjacent the electrodes to regulate gas flow between the high thermal conducting surfaces. |