205,188 research outputs found
Star tracking reticles
A method for the production of reticles, particularly those for use in outer space, where the product is a quartz base coated with highly adherent layers of chromium, chromium-silver, and silver vacuum deposited through a mask, and then coated with an electrodeposit of copper from a copper sulfate solution followed by an electrodeposit of black chromium is described. The masks are produced by coating a beryllium-copper alloy substrate with a positive working photoresist, developing the photoresist, according to a pattern to leave a positive mask, plating uncoated areas with gold, removing the photoresist, coating the substrate with a negative working photoresist, developing the negative working photoresist to expose the base metal of the pattern, and chemically etching the unplated side of the pattern to produce the mask
Process for the production of star-tracking reticles
Reticles designed with quartz bases are masked with desired pattern and then are coated with highly adherent layers of chromium, chromium silver alloy, silver, copper, and black chromium (mixture of chromium and chromium oxides). Black chromium final layer produces required nonreflective surface
Debris control design achievements of the booster separation motors
The stringent debris control requirements imposed on the design of the Space Shuttle booster separation motor are described along with the verification program implemented to ensure compliance with debris control objectives. The principal areas emphasized in the design and development of the Booster Separation Motor (BSM) relative to debris control were the propellant formulation and nozzle closures which protect the motors from aerodynamic heating and moisture. A description of the motor design requirements, the propellant formulation and verification program, and the nozzle closures design and verification are presented
Ground Water Quality Effects on Domestic Water Utilization
The work upon which this report is based was supported in part by
funds (Project A-040-ALAS) provided by the United States Department of
the Interior, Office of Water Resources Research, as authorized under
the Water Resources Act of 1964, as amended
Formation of star tracking reticles
The present application is directed towards a process for producing high resolution, substantially non-reflective reticles or choppers suitable for use for transmitting in both the visible and near ultra-violet regions, able to withstand reasonable handling and extreme environmental conditions, and capable of operating at speeds of from 2800 to about 9000 revolutions per minute without distortion. In particular, the present invention is directed towards the production or reticles having a quartz base vacuum coated with chromium, chromium-silver alloy, and silver with electrodeposited copper and black chromium thereon, respectively, in the form of a reticle pattern. The quartz permits the transmission of light while the pattern is opaque to light. The reticles of the present invention are intended for use in optical trackers, such as star trackers used in outer space
Effect of oxygen concentration on the structural and magnetic properties of LaRh1/2Mn1/2O3 thin films
Epitaxial LaRh1/2Mn1/2O3 thin films have been grown on (001)-oriented LaAlO3
and SrTiO3 substrates using pulsed laser deposition. The optimized thin film
samples are semiconducting and ferromagnetic with a Curie temperature close to
100 K, a coercive field of 1200 Oe, and a saturation magnetization of 1.7muB
per formula unit. The surface texture, structural, electrical, and magnetic
properties of the LaRh1/2Mn1/2O3 films was examined as a function of the oxygen
concentration during deposition. While an elevated oxygen concentration yields
thin films with optimal magnetic properties, slightly lower oxygen
concentrations result in films with improved texture and crystallinity
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