Abstract: A method for forming a gas-permeable and ion-permeable membrane comprising fully impregnating a porous ion-impermeable or non-conductive polymer substrate with an ion-conducting polymer material to form a composite and subsequently stretching the composite to re-form pores in the substrate. The resulting membrane comprises regions of the ion-conducting material juxtaposed to the gas-permeable pores formed in the substrate by the stretching process.

Abstract: An electrode apparatus adapted for use in electrochemical systems having an anode compartment and a cathode compartment in which gas and ions are produced and consumed in the compartments during generation of electrical current. The electrode apparatus includes a membrane for separating the anode compartment from the cathode compartment wherein the membrane is permeable to both ions and gas. The cathode and anode for the assembly are provided on opposite sides of the membrane. During use of the membrane-electrode apparatus in electrochemical cells, the gas and ions generated at the cathode or anode migrate through the membrane to provide efficient transfer of gas and ions between the anode and cathode compartments.

Abstract: A first embodiment includes a set of diffraction gratings on the face of a wheel, each grating being set at an angle to select a different spectral line. The wheel is rotated, and as each grating moves into the end-reflector position of the laser's optical path, the laser is fired. Alternate embodiments include a small spinning fold mirror that reflects the beam in a circle about the axis of the laser.

Abstract: A method is disclosed for the strain-free mounting of a component, such as a mirror, in a manner that allows differential thermal expansion or contraction to take place without distortion of the component. The mounting method makes use of a linear bearing that is rigid in all directions except one. Such a linear bearing is used at two or more points of support on the circumference of a mounting circle or circles. Relative motion in the linear bearings occurs along a line which is an extension of a radius of the mounting circle. The linear bearings each contain two sets of opposed rolamite mechanisms moving in parallel directions in the perpendicular arms of a "Y"-shaped frame.

Abstract: A lightweight mirror comprises a silicon carbide (SiC) foam core having a bulk density of approximately five percent. The mirror further comprises two solid facesheets each of which is integrally formed upon a surface of the SiC foam core, the facesheets being comprised of SiC. Upon a machined surface of one or both of the facesheets a further layer of SiC is deposited to reinforce the SiC facesheet and to provide an optically polishable surface. This outer layer of SiC may be deposited by chemical vapor deposition (CVD) techniques. After depositing this reinforcing layer of SiC, the layer is machined and polished to provide a mirror surface having a desired flatness and optical quality.

Abstract: Point and area target tracking are employed by a dual mode video tracker which includes both a correlation processor (30) and a centroid processor (32) for processing incoming video signals representing the target scene (20) and for generating tracking error signals over an entire video frame. A microcomputer (26) controls the operation of the correlation and centroid processors, as well as a preprocessor (28) which preconditions the incoming video signals. The tracker operates in any of several modes in which the correlation and centroid processors function either independently or cooperatively with each other. The correlation processor generates a reference map in pixel format which is used to produce azimuth and elevation optimal weighting values for each pixel in the field-of-view. The reference map is recursively updated. The track gate for the correlation processor is automatically sized using a gradient function derived from the optimal weighting values.

Abstract: Method and apparatus are disclosed for automatically and remotely removing unwanted organic films from surfaces of vehicles and satellites in space. A particle beam generator (12) draws molecular oxygen from an on-board supply chamber (14) and develops a stream of positively charged oxygen ions (40). These ions are directed towards a surface or component of a spacecraft such as a solar cell, radiation emission aperture, or sensor objective lens (44) which has been coated by an opacifying, organic contaminant layer (42) that impairs the efficacy of the spacecraft. The ions (40) bombard the contaminant layer (42) and remove it by both kinetic interaction and chemical oxidation. Spacecraft surfaces and components may be restored and renewed to their original operational capabilities through this method of volatilizing debilitating occluding residues which have been hardened by solar radiation away from the spacecraft as harmless gases (50).

Abstract: An electrode for a transverse gas flow laser has a simplified profile which facilitates the fabrication and subsequent alignment of the electrodes within a laser cavity. Each electrode is essentially comprised of an upper horizontally planar surface having a surrounding radiused edge of a given radius of curvature which is terminated by a surrounding vertical side wall. The termination of the radiused edge by the side wall acts to reduce the total electrode width, resulting in a reduction in required laser package size. A bottom surface of the electrode may be provided with a mounting means, such as a plurality of tapped openings for bolting the electrode to an inner surface of the laser package.

Abstract: A method and apparatus are disclosed for testing for stuck open faults in integrated circuits (10) having a plurality of combinational logic devices (18, 20). The apparatus includes a chain or shift register stages (22), with each stage including at lest two latches (L1and L2). Provision (43) is made for interleaving the bits of an initialization test pattern (40) with the bits of a detection test pattern (42) prior to loading the resultant serial data stream into the shift register stages (22). Once loaded, the latches (L2) contain the initialization test pattern whereas the latches (L1) hold the detection test pattern. A multiplexer (52) is provided for selecting one of the outputs from the two latches (L1, L2) so that the initialization test pattern and then the detection test pattern can be quickly applied to the combinational logic so as to minimize hazards which could invalidate the test results.

Abstract: Uniform electrical heating of a circular, single crystal germanium window (18) uses its bulk resistance and pairs of electrodes (20) equally spaced about the window's periphery. The electrode pairs are sequentially switched at a rate high enough to avoid thermal switching transients.

Abstract: A system for protecting a radiation-responsive device, such as an infrared sensor in an imaging system includes a plasma switch operative in response to amplitude of incident radiation. The protection system is suitable for protecting the infrared sensor from a high-intensity laser beam which might impinge upon receiving optics of the imaging system. The plasma switching responds differently to different portions of the electromagnetic spectrum, a lower frequency portion being either transparent or reflective of the infrared radiation, while an upper frequency portion absorbs radiation to initiate a high or low density of free-charge carriers in the plasma dependent on the intensity of photons injected into the plasma in the higher frequency band.

Abstract: A head-up display for use in a vehicle is provided with a curved combiner which reflects an image from a cathode ray tube (CRT) as collimated rays to a viewing site. A relay lens is positioned between the CRT and the combiner to magnify and transfer the image. The combiner may be a partially-reflecting mirror or holographic optical element or dielectric laminate. Included within the relay lens is a coma-control plate having two-dimensional undulations described mathematically by a two-dimensional power series having odd symmetry in a plane of a tilting of the combiner and even symmetry in the perpendicular dimension. The coma-control plate substantially reduces coma in an image presented for viewing at infinity, the coma being introduced by the curvature and off-axis use of a surface of the combiner.

Abstract: An apparatus and method for measuring the surface contour of an aspheric optical surface 36. This is accomplished by splitting a single coherent beam of light into two individual beams with one beam tilted with respect to the other. The degree of tilt is adjusted until a single interference fringe is observed. This single fringe is then directed onto the aspheric surface 36 under test by means of a focusing lens 30. By the use of a beam spliter 24 the reflected fringe is then directed onto a multi-element optical detector 40 . The shape of the fringe reflected onto the detector 40 corresponds to the shape of the aspheric surface 36. A phase modulating mirror 26 is then moved to increase or decrease the path length of one of the two interfering beams of light. This results in sweeping the fringe across the entire aspheric surface 36 so that the entire aspheric surface 36 can be measured. The result is an easy to perform measurement of the aspheric surface 36 which is close to diffraction limited.

Abstract: Layers (12, 14) of a multilayer flexible cable (10) are directed about a bend (22), so that the layers are configured into inner (12) and outer (14) layers. Differently configured spacers (20, 72, 74, 76) are placed between the respective layers at the bend for guiding the outer layer in a path (24) which follows the bend and for guiding the inner layer or layers in a path (26) or paths which is or are generally reversely directed from that of the outer layer.

Abstract: A CO.sub.2 TEA laser Q-switch uses an intra cavity rotating prism (70) with internally reflecting surfaces (76, 78) at near the critical angle to produce a variable optical loss such that the gain of the laser is switched as the prism rotates through the critical angle. The nitrogen tail portion of the laser output pulse can be eliminated by switching the gain just after the main pulse at the beginning at the tail. An opto-electronic timing device (100), which includes a graded index glass rod (101) rotating with the Q-switch prism, generates a pulse (88) to initiate the laser discharge at the proper lead time before the prism switches the resonator gain.

Abstract: Apparatus is disclosed for the strain-free mounting of a component, such as a mirror 11, to a base in a manner that allows for differential thermal expansion or contraction to take place between the component and the base without distortion of the component. The mounting apparatus of the invention makes use of a linear bearing 10 that is rigid in all directions except one. Such a linear bearing is used at two or more points of support on the circumference of a mounting circle A. Relative motion in the linear bearings occurs along a line r which is an extension of a radius of the mounting circle. The linear bearings each contain two sets of opposed rolamite mechanisms 20a, 20b, 30a, 30b moving in parallel directions in the perpe=ndicular arms of a "Y"-shaped frame 18.

Abstract: A four mirror afocal optical system is disclosed. The primary mirror (12), secondary mirror (14), tertiary mirror (16), and quaternary mirror (18) form an afocal reimaging optical system which is off axis in both aperture and field angle. The secondary, tertiary and quaternary mirrors are tilted and decentered relative to the optical axis of the primary mirror to enhance image quality and to provide access to a real exit pupil.

Abstract: A cryogenic cooler (10) includes a dewar (14) spaced from a cold finger (12). In the space (18) between the dewar and the cold finger, a trace amount of a noncondensable gas, preferably neon, is added to the air to maintain the thermal conductivity between the cold finger and the dewar and thereby to prevent temperature cycling in the cooler.

Abstract: An afocal zoom lens system is provided that has particular utility for use in aircraft navigation systems where a unitary (1.0.times.) magnification power is desirable. Two embodiments are disclosed, the first providing an 8:1 magnification ratio with the second embodiment providing a 12:1 ratio. Both embodiments employ four lens groups including a front fixed objective lens (A,E), a second lens group including a negative zooming element (B,F), a third fixed group (C,G) and a fourth rear negative zooming element (D,H). In the highest magnification position, the lenses are arranged so that the front zooming element is positioned adjacent the positive lens of the the third group to form a weak negative doublet. In the minimum magnification position, the front zoom element is widely separated from the third group to create an inverse telephoto Galilean form.

Abstract: Horizontal and vertical deflection windings in a deflection yoke coil assembly of a CRT (cathode ray tube) having stroke written or raster scan displays are driven by x and y analog deflection signals, respectively. Each of the x and y analog deflection signals are converted to x and y digital signals, respectively, sampled to provide x, y sample sets which are coupled to a digital x correction signal memory and a digital y correction signal memory, respectively. Geometric corrections are stored in the memories for each of a predetermined number of x, y signal set values which correspond, respectively, to a number of point locations over the CRT screen. The x and y corrections that are addressed from the memories are supplied to MDACs (multiplying digital to analog converters) and then to analog delay line filters which supply the x, y analog correction signals for summing with the x, y analog deflection signals, respectively.