Abstract: A parallel or serial analog-to-digital converter utilizing both Gunn effect devices and field effect transistors. The converters are based on a differential pair of amplifiers consisting of two or more Gunn effect devices, one of which is biased close to the knee of the current-voltage characteristic before the negative resistance region. Hence a clock pulse will bias one of the devices into the negative resistance region while the other device is now biased close to the knee to be able to respond to the analog signal. This is due to the fact that both devices are biased by a common constant current source, including a field effect transistor.

Abstract: A digital speedometer, frequency or event counter with digital display. The speedometer conventionally receives speed pulses representative of the speed of the vehicle. Due to the lack of synchronization between speed pulses and clock pulses the last display digit exhibits undesirable jitter. This may also be caused by backlash in the drive train or the like. This jitter is minimized by the provision of a precounter between the counter and the gate transfer to a storage register. This will permit transfer of the number generated in the counter only if the precounter is in the zero state, thus minimizing the jitter due to random occurrences of the last pulse.

Abstract: A fiber reinforced composite tube is molded by applying an annular, liquid-resin-impregnated layer of reinforcing fibers to a cylindrical mold or mandrel; placing in contact with the exposed surface of the fiber-resin layer a compression sleeve which is split lengthwise to permit circumferential contraction or expansion of the sleeve into pressurizing relation with the layer; pressurizing the compression sleeve with fluid pressure to compress the fiber-resin layer and thereby compact the reinforcing fibers and expell entrapped air and excess resin from the layer; and curing the resin while the fiber-resin layer is so compressed.

Abstract: A welding method and machine for fabricating a wire network by supporting a group of wires in spaced side by side relation, intermittently advancing the wire group endwise through a welding station, and following each advance of the wire group, supporting at least one wire within the welding station in a transverse welding position relative to the group wires, such that the group and transverse wires cross one another, and welding the group and transverse wires to one another at their crossing points to form a welded wire network comprising the group wires and a multiplicity of transverse wires spaced along and welded to the group wires. The invention is described in connection with fabricating gore shaped wire networks which may be assembled to form a parabolic antenna reflector.

Abstract: An instrument for determining the stress in the wall of a borehole by recording successively on the same holographic recording medium two holograms of a selected surface region of the wall, and, in the interval between the two recordings, forming a stress relief in the wall in stress relieving relation to the surface region to produce on the recording medium a double exposure hologram. This hologram contains holographic information which represents the stress in the wall in the vicinity of the surface region and may be converted to data defining the magnitude and direction of the stress.

Abstract: A method for the removal of particulate matter as well as noxious gases and vapors from a gas stream. This is accomplished by means of charged droplets having a size between 60 and 250 microns and preferably between 80 and 120 microns. The droplets are generated by first ejecting a stable jet of liquid such as water. The liquid jet is broken up into charged droplets by applying an electric potential between the jet and the collecting walls of the scrubber. Since most gases are electronegative the droplets are preferably charged positively by the resultant electrostatic field. However, in case some of the particles are already charged it is preferred to generate charged droplets having a polarity which is the same as that of the particles. The method works well with particles having a diameter of approximately 0.01 micron or more and the droplets are preferably moved at an angle to the direction of movement of the gas stream to increase the relative velocity between the droplets and the particles.

Abstract: This invention relates to high-temperature, oxidation-resistant refractory materials or alloys and to a method of preparing said alloys which have an outer skin containing at least one noble metal, e.g., platinum, and/or silver, in amounts greater than the amount of noble metal present in the alloy beneath said skin. The alloy comprises at least one noble metal selected from the group consisting of platinum, gold, silver, rhodium, iridium and palladium. The noble metal is added in amounts ranging from 0.1 to 15% by weight of the total composition to hafnium or to hafnium containing from about 0 to 50% by weight of zirconium, and heated to temperatures ranging from about 1000.degree.F to 3800.degree.F in an oxidizing atmosphere.

Abstract: A low temperature curing polymeric adhesive composition may be made by reacting an amino alcohol having between 1 and 3 amino groups and between 2 and 5 hydroxyl groups with a stoichiometric amount of a carboxylic acid or derivative. Free radical catalysts and accelerators may be added to speed the cure of the adhesive. These adhesive resins can be cured at or near ambient room temperature and are highly desired for fabrication of bonded materials possessing long fatigue life because of reduced stresses that might be induced at higher cure temperatures. A generalized formula may be illustrated as follows: ##EQU1## WHERE R" may be hydrogen, alkyl, or cycloalkyl; R' may be hydrogen or alkyl; R is an alkyl; R.sub.1 may be hydrogen, an alkyl, or phenyl; m is an integer from 1 to 3; and n is an integer from 1 to 2.

Abstract: Disclosed is a method and apparatus for reproducing remotely sensed images in which the effect of attitude perturbation in the sensing device is removed from the image.The image is acquired by means of an electromagnetic radiation sensor mounted on a non-stationary body, such as an earth satellite, a helicopter, or the shoulder of a cameraman. An electronic signal representative of the three-axis attitude perturbation of the sensor is generated simultaneously with the data signal from sensor and a signal representative of the instantaneous nominal attitude thereof. These signals are transmitted (in some cases with the intermediate step of tape recording) to an image reproduction device such as a cathode ray tube or a portion of photographic film exposed by a narrow-beam light source. The data signal activates the image generator (i.e., the electron beam or the exposing light source); the signal corresponding to the nominal sensor attitude scans the image generator (e.g.

Abstract: A compliant polyimide having superior thermal-mechanical properties can be produced by reacting an aromatic bis(furfurylimide) with an aliphatic ether bis(maleimide) via a Diels-Alder reaction. These polyimides display a long-term thermal-oxidative stability and a high percent recoverable elongation to break, and they are suitable for use as films, fibers, coatings, adhesives, structures, and sealants.

Abstract: A sensor, such as a radar, is mounted on a moving vehicle equipped with a speed control system which normally maintains the vehicle speed constant at a pre-set speed in the absence of a preceding vehicle within a safe distance. The sensor detects the presence of a preceding vehicle and measures the distance and closing speed of the controlled vehicle with respect to the preceding vehicle, and generates an adaptive speed signal. The adaptive speed signal modifies the error signal of the speed control system which controls either the throttle or brake to cause the controlled vehicle to match its speed to the speed of the preceding vehicle, and to maintain a safe distance from it, thereby making the adaptive speed signal vanish. The error signal may be modified by the adaptive speed signal either by decreasing the desired speed or by increasing the actual speed. The desired, actual, and adaptive speeds may all be represented by digital numbers.

Abstract: Disclosed is a plurality of motors mechanically connected in series so as to provide operational redundancy. The shaft of a given motor is rigidly attached to the housing of the next motor in the series, so that rotation of the first shaft will cause the second motor and its shaft to rotate. Means are provided to prevent relative rotation of the rotors of the redundant motor(s). Other means are provided to detect failure of the operating motor and to activate another motor in the series when this occurs.

Abstract: A semiconductor substrate is coated with an insulating film followed by a layer of polysilicon. The polysilicon layer is coated with a non-oxidizable mask, such as silicon nitride, and then oxidized to convert the exposed regions to silicon oxide and add further thickness to the converted oxide regions. When the mask is removed, the thicker silicon oxide regions serve as an in situ mask for selectively implanting impurity ions through the thinner polysilicon regions and into the semiconductor substrate. When the silicon oxide regions are etched away, the remaining polysilicon regions serve as an ion implantation mask for permitting selective ion implantation through the voids left by etching the silicon oxide regions.

Abstract: The present invention relates to a digital system for maintaining the speed of a motor vehicle at a preselected speed. The desired speed of the vehicle is set into a digital memory bank and the instantaneous actual speed of the vehicle is determined by a digital readout. The desired vehicle speed and the actual speed of the vehicle are compared to produce a digital error signal which is used to control the throttle setting of the vehicle to cause the actual speed of the vehicle to equal the desired speed.

Abstract: Preparation of a novel heterocyclic peri acid is initiated by reacting diaminodimethylbiphenyl with methyl vinyl ketone to produce tetramethyl biquinoline. The substituent methyl groups are oxidized subsequently to produce a tetraacid, or upon dehydration of the tetraacid, a dianhydride. The peri acids of this invention have the following structural formula: ##SPC1##Where R may be either ##EQU1## or (--COOH).sub.2 and R' is--H, --OCH.sub.

Abstract: The present invention relates to a digital system for maintaining the speed of a motor vehicle at a preselected speed. The desired speed of the vehicle is set into a digital memory bank and the instantaneous actual speed of the vehicle is determined by a digital readout. The desired vehicle speed and the actual speed of the vehicle are compared to produce a digital error signal which is used to control the throttle setting of the vehicle to cause the actual speed of the vehicle to equal the desired speed.

Abstract: Apparatus and method wherein a photographic plate is doubly exposed by pulsed laser illumination to record successive instants in the history of an object under consideration. The doubly exposed plate is then developed and the photograph or hologram is used to reproduce the object in full three-dimensional detail including subtle changes in the object in the form of interference fringes where the hologram is illuminated with continuous laser illumination.

Abstract: Disclosed is an electrical circuit board structure incorporating a ceramic substrate wafer and metallic mounting means bonded to the substrate wafer for securing the structure to a housing. The metallic portion of the structure protects the ceramic wafer from mechanical stresses transmitted through the housing by providing structural integrity and dynamic isolation. Selection of such a metallic material having its coefficient of thermal expansion similar to that of the substrate material prevents the creation of thermal stresses between the ceramic and the metal portion of the structure.The disclosed method comprises rigidly securing the ceramic substrate circuit board to the metallic member in such a way that the latter may be attached to the housing without stressing the ceramic material.

Abstract: Disclosed is an improved method of bonding two glass-like structures or a glass-like and a metallic structure, and an improved bond which may be fabricated by this method. In the preferred embodiment, the mating surfaces are first metalized with a thin titanium layer, which is covered by a thin gold layer. The metalized surfaces are joined, and a gold layer is electro-deposited over the junction in an overlapping fashion. Finally a nickel layer is electro-deposited over the gold layer.

Abstract: A broadband waveguide mixer suitable for the microwave and millimeter wave regions is described. The mixer is characterized by having a unique dual-guide mixer mount through which extends two parallel and spaced waveguides. The RF wave and the local oscillator wave are respectively impressed on the two waveguides via a hybrid coupler. A pair of crossbars extend through each waveguide. A pair of diodes connected back-to-back are disposed in each waveguide and are connected to the respective crossbars. Each pair of diodes has a polarity opposite to that of the other pair. The output is derived from a coaxial cable connected to the adjacent ends of the two crossbars. The input signals may be applied by a folded hybrid tee or a short slot hybrid coupler to simplify the input structure. The mixer has low noise and broadband performance.