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This horn antenna for a prototype clear-air-turbulence warning system is rotatable through ±45°. Installation is in a wheel well in the NASA C-141 Kuiper Airborne Observatory aircraft.
Illumination and detection axes in a set of proximity sensors are chosen to intersect at prescribed distances. An object that enters any of the fields of view defined by the intersections will reflect light to one or more of the detectors. This system has some redundancy: Both detector boxes
Group of light sources or detectors is mounted in a box at the focal plane of a lens. Each box can therefore illuminate or view several axes, each corresponding to a source or detector of the group.
Thick fiber cladding is partly stripped away so that the grating will be formed near the core. To form a flat substrate for the grating (above), the fiber is encased in epoxy, then polished flat. To form a round substrate for the grating (below), the cladding is chemically etched through most of its thickness.
Photoresist is holographically exposed, developed, and ionmilled to produce the corrugations of the grating surface. This is a round grating of the type shown in Fig. 4, except that it is on a thickwall cladding.
For the lensless telescope, the aperture function shows the area of the inner aperture exposed to a distant source as a function of the viewing angle.
Laser interferometers (color) are used to measure mirror angle
Fast computer-controlled sampling of an optical KER signal increases the accuracy of optical-system aberration measurement. The inset shows a typical KER signal plotted against the position of one rotating bar on a knife-edge wheel.
Operating principle of the viewer is illustrated in simplified form with a triangular object
Six-channel beam splitter has optical paths of lengths equal to the distances traveled by the rays within the hatched section shown in the lens. The lens element cemented to each of the exit faces of the beam splitter is optically concentric with the element cemented to the entrance face and with the center of curvature of the monocentric optical system. The precise dimensions of each exit element are chosen to optimize performance in the wavelength band exiting in each channel.
In this waveguide coupler close tolerances are achieved for high-efficiency coupling between optical fibers with a core diameter of 5
This color-film storage vault contains a nonoxidizing atmosphere that retards the fading of high-speed-emulsion color dyes. An externally controlled valve regulates the flow of nitrogen gas from an internally mounted tank. The gas purges ambient air from the vault through the purge valve and maintains the vault pressure slightly above ambient.
Setup for measuring light-beam-induced currents closely simulates the solar wavelength and intensity. The apparatus measures the short-circuit current generated when a 5- × 12-
Gas-chromatographic separation of a hydrocarbon mixture is shown for a column packed with 3,4-dichlorophenylisocyanate-modified Porasil. A helium-ionization detector was used.
Beam from a helium-neon laser is split into two beams by an angled interferometer flat after a neutral-density filter has reduced the original beam intensity to a level that will not heat the oil film. The reflected upstream and downstream beams are directed to separate photodetectors.
Examples of solar-cell slide-rule calculations are determination of allowable impurity concentration for a nonredistributive process (top), determination of the impurity-buildup factor for a redistributive process (middle), and determination of allowable impurity concentration for a redistributive process (bottom).
Breakup of a silicon stream into drops is controlled, in part, by varying the frequency of vibrations imparted to the stream by an ultrasonic transducer. Drop size is monitored by the photodetector.
Honeycomb-surface radiation sink is used in a space-background simulator. The new bias-cut honeycomb cell geometry guarantees that at least two specular reflections occur before the incident radiation escapes. With straight-cut honeycomb geometry, incident radiation from some directions escapes after just one reflection. The bias-cut geometry yields an overall absorptance closer to unity. Sample radiation paths are shown.