Abstract: A microlens of any designed configuration is formed as a replica in a photoresist material, and the photoresist material replica is used to reproduce the replica directly in a substrate material.

Abstract: An optical coupler 13 comprises a monolithic block of transparent optical material with a pair of opposite sides configured so that an optical signal can be transmitted between a first device 12 and a second device 14 with internal reflections within the coupler 13. Because the optical coupler 13 is monolithic, thermal expansions and contractions in response to extreme fluctuations are uniformly distributed throughout the coupler 13 and therefore do not significantly distort the optical signal.

Abstract: A 10.times. laser beam expander lens that is well-corrected for chromatic aberration can be used without refocussing over a wavelength range from 0.365 micron to 1.3 micron.

Abstract: In a liquid storage tank 10 for use on a spacecraft, a transfer apparatus 15 (comprising gathering vanes 33, an elongate array of fins 32, and a sponge structure formed from panels 31) functions to transfer liquid from the inner surface of the tank 10 to the vicinity of an outlet line 40. A screen 23 is disposed between the panels 31 and the outlet line 40. When wetted with liquid, the screen 23 prevents gas and/or vapor in the tank 10 from passing to the outlet line 40. A perforated plate 22 disposed between the screen 23 and the outlet line 40 causes liquid to pass from the tank 10 to the outlet line 40 in a regular and generally unbroken flow.

Abstract: In a liquid storage tank 10 for use on a spacecraft, a transfer apparatus 15 (comprising gathering vanes 33, an elongate array of fins 32, and a sponge structure formed from panels 31) functions to transfer liquid from the inner surface of the tank 10 to the vicinity of an outlet line 40. A screen 23 is disposed between the panels 31 and the outlet line 40. When wetted with liquid, the screen 23 prevents gas and/or vapor in the tank 10 from passing to the outlet line 40. A perforated plate 22 disposed between the screen 23 and the outlet line 40 causes liquid to pass from the tank 10 to the outlet line 40 in a regular and generally unbroken flow.

Abstract: A method and apparatus are disclosed whereby a received signal comprising a binary spreading-code sequence, which belongs to a set of binary spreading-code sequences available to a transmitting node of a multi-node communication network, can be analyzed to determine the particular sequence from the set of sequences available to the transmitting node that was actually transmitted. All sequences of the set of available sequences have the property that each sequence can be generated by the same configuration of two linear feedback binary shift registers, where the feedback taps on the two binary shift registers correspond to primitive polynomials of the same degree over GF(2), the field of two elements. The received signal is correlated with each sequence of the set of available sequences to obtain a set of correlation values. The correlation values having the largest and the next-largest magnitudes are compared, and if their ratio exceeds a predetermined threshold, a detection decision is made.

Abstract: In a tank 10 for cryogenic liquid to be used in a low-gravity environment (e.g., on a space vehicle), a liquid transfer apparatus 15 (which comprises an elongate array of fins 32 and a sponge structure formed from panels 31) functions to transfer cryogenic liquid from the interior of the tank 10 to a bowl structure 20 defining a reservoir region adjacent an outlet of the tank 10. A perforated plate 22 disposed between the sponge structure and the outlet of the tank 10 causes cryogenic liquid to pass through the outlet into an outlet line 40 in a regular and generally unbroken flow. To prevent any substantial amount of heat transfer into the reservoir region of the tank 10, the bowl structure 20 is separated from the inner surface of the tank 10 by a capillary distance in order to provide a thermally insulating space therebetween.

Abstract: An adaptive control includes a digital error correction system (DECS) to reduce control system error to near zero by anticipating a problem and feeding forward in time a correction to deal with the problem before it happens. The adaptive control is used in a controlled system of the kind which is cyclical in operation and which operates in response to repetitive cycle commands so that the operation of the system is substantially predictable for a significant number of cycles of operation. The adaptive control is incorporated in a refrigerator system in which two Stirling cycle refrigerators are mounted in opposition to one another. The adaptive control permits accurate control of the command waveform frequency and shape, enables the refrigerator system to be more thermodynamically efficient, and enables the two refrigerators to exactly cancel each other's vibration.

Abstract: An array of solar cells for supplying electrical energy to a building (e.g., for operating air-conditioning equipment) is mounted in a window fitting, which comprises a pair of transparent glass panes between which a window blind (e.g., of the venetian blind type) is mounted. Solar cells are secured to slats of the window blind so as to be exposed to sunlight incident thereon.

Abstract: A method and apparatus for communication in a spread spectrum network are disclosed. Blocks of bits embodying information are assigned to corresponding subsets of binary spreading code sequences and at least one of the subsets of binary spreading code sequences contains more than one binary spreading code sequence. Selected subsets of the binary spreading code sequences are then simultaneously transmitted from a transmitting node to a receiving node.

Abstract: A method is described for selecting optical materials to use in designing color-corrected optical systems. Various dioptric, catadioptric and anamorphic optical systems are described, which use only two different types of optical materials to obtain precise axial color correction at three, four or five wavelengths (depending upon the particular optical materials), with only very small chromatic aberration occurring at wavelengths between the precisely color-corrected wavelengths. Examples of color-corrected lens systems comprising more than two glasses are also described.

Abstract: A method is described for selecting optical materials to use in designing color-corrected optical systems. Various dioptric, catadioptric and anamorphic optical systems are described, which use only two different types of optical materials to obtain precise axial color correction at three, four or five wavelengths (depending upon the particular optical materials), with only very small chromatic aberration occurring at wavelengths between the precisely color-corrected wavelengths. Examples of color-corrected lens systems comprising more than two glasses are also described.

Abstract: An antenna system is provided having a plurality of individual antenna elements located on a foldable platform. The antenna elements are appropriately phased to yield a desired radiation pattern. The platform has a plurality of light-emitting devices mounted at predetermined locations on the platform. Light from each of the light-emitting devices passes through a corresponding window assembly on a hub. A biconical reflector within the hub directs rays of light from all the light-emitting devices through a telescope and a system of mirrors which focus the rays so as to form images on photodetector arrays. The images formed by the focused optical signals relate to the actual configuration of the platform.

Abstract: A non-pyrotechnic release system for use in satellites and other remote actuations applications is disclosed. This system employs shape memory rod assemblies to release a captive toggle that retains the item to be deployed. The shape memory rod assembly includes an internally installed resistance heating element for heating the rod to cause it to assume its memory shape.

Abstract: Glints (e.g., images of point sources attributable to specular reflections) are suppressed in the focal plane of an optical imaging system by:a) Fourier-transforming an image of the imaging system's object field (including glints), and dividing the resulting energy distribution into a first channel and a second channel;b) focussing the energy in the first channel onto a first diffraction grating so as to impose a periodic carrier on the image, thereby producing a first image signal;c) directing the energy in the second channel so as to illuminate a Fourier-transform hologram of the complex point response of the imaging system to which additional aberrations (preferably toroidal aberrations) have been added;d) focussing the energy distribution from the hologram onto a second diffraction grating that is 180.degree. out-of-phase with the first diffraction grating, and blocking higher diffracted orders, thereby producing a second image signal;e) superimposing the first and second image signals (which are 180.

Abstract: An object (10) to be radiographically inspected is irradiated in a sequence of different positions with respect to an X-ray beam emitted by a single source (12). A single X-ray detector in an imaging system (13) produces a series of electronic signals corresponding to the sequence of positions at which irradiation of the test object (10) occurs. The series of electronic signals is converted to a pair of series of signals, wherein one series of the pair is delayed with respect to the other series of the pair. The pair of series of signals is displayed as a stereoscopic pair of series of visual images corresponding to different positions at which the test object (10) is irradiated by the X-ray beam. A viewing system (19) causes each eye of an observer to see a different series of visual images, whereby the observer is enabled to preceive a series of stereoscopic X-ray images of the test object (10).

Abstract: An aligned metal gate is formed on a semiconductor substrate surface between a source region and a drain region of the substrate. Precise alignment of the boundaries of the gate with the boundaries of the source and drain regions is obtained by shadowing a photoresist coating over metal deposited onto the substrate surface, while photochemically dissociating the photoresist over metal deposited onto an oxide layer formed over the source and drain regions of the substrate. The developed photoresist is removed, and the undeveloped photoresist is hard-baked to serve as a protective coating for the metal between the source and drain regions. The metal over the source and drain regions is etched away, leaving the metal between the source and drain regions to function as an electronic gate.

Abstract: This invention relates to terbium activated silicate luminescent glasses exhibiting reduced afterglow and enhanced luminescence due to incorporation therein of selected rare earth oxides of cerium, europium and godolinium.

Abstract: This invention relates to terbium activated silicate luminescent glasses exhibiting reduced afterglow and enhanced luminescence due to incorporation therein of selected rare earth oxides of cerium, europium and gadolinium.

Abstract: A catadioptric zoom relay telescope whose refractive elements are made from only a single type of optical glass focuses all wavelengths in a broad infrared bandwidth onto a common focal plane with diffraction-limited imagery throughout a changing focal ratio (i.e., a zoom range) from less than f/1.5 to more than f/6.0.