Abstract: An articulated element for an antenna such as a log-periodic dipole antenna having an elongated boom comprises an inner tubular section secured to the boom and an outer tubular section movable relative to the inner section between an extended or operative position colinear with the inner section to a folded or inoperative position transversely of the inner section. The element sections are interconnected by spring means which is always in tension and exerts a compressive force between the two sections for good electrical conductivity when in the operative position while permitting the outer section readily to be pivoted to the stowed position. A T-shaped sleeve secured to the inner section has slotted longitudinal and transverse legs which releasably clamp and provide strong mechanical support of the outer section in both positions.

Abstract: An integrated erectable antenna system comprises a mast pivotally mounted for rotation between a horizontal stowed position and a vertical operative position, and a log-periodic antenna assembly longitudinally slidably and pivotally mounted on the mast for movement between stowed and operative positions. The pivoted end of the mast has an extendible arm connected by cable to a hand operated winch. The antenna assembly comprises an elongated boom having many articulated transverse dipoles connected thereto over its length and foldable for stowing without disconnecting the dipole parts. The boom is hinged to the mast about one axis transverse to the latter for pivoting from a stowed position parallel to the mast to an operative position perpendicular to the mast and about another axis parallel to the boom for orienting the dipoles in either horizontal or vertical planes when the mast is in the vertical position.

Abstract: An efficient circuit for coupling at least two radio frequency transmitters of arbitrary power and frequency to one antenna comprises a three-port ferrite circulator connected to the output of each transmitter, a tee connector with a predetermined impedance mismatch connected to the first output port of each circulator, a first in-phase power combiner connected to the second output port of each circulator, and a second in-phase power combiner connected to the outputs of the tee connector and first combiner for adding the RF power and feeding the attached antenna. The impedances of transmission lines connected to the tee connector are selected to present a 3 to 1 voltage standing wave ratio to input lines so that reflected power is equally divided and fed in segments of equal power, phase and amplitude to that of the original summation for recombining and delivery to the antenna. The circuit effectively isolates the transmitters from each other and combines their outputs with high efficiency and minimum loss.

Abstract: An efficient circuit for coupling at least three radio frequency transmitters of arbitrary power and frequency to one antenna comprises a three-port circulator connected to the output of each transmitter, a four-port connector and a five-port inphase power combiner, and transmission lines having the same characteristic impedances connecting the circulators through the connector and the combiner to the antenna. The transmission lines interconnecting the components of the circuit have electrical lengths selected to deliver energy in phase to the ports of the connector and to the combiner. In a three-transmitter embodiment, one output port of each circulator is connected to the connector, a second output port of each circulator is connected to the combiner, and the output port of the connector is connected to the combiner. In a four-transmitter embodiment, one output port of each circulator is connected to the connector and the second output port of each circulator is connected to the combiner.

Abstract: An electronically switchable multiwavelength laser system comprises a lasing medium capable of generating a beam having at least two different wavelengths, an anisotropic birefringent component in optical alignment with the medium for refracting the beam into spatially separate polarized rays containing both wavelengths, and another electrically controllable anisotropic electrooptically active element, such as a Pockels' cell, having electrodes aligned with the respective rays and selectively energizable to block either ray to permit the laser to oscillate at the wavelength and polarization of the unblocked ray. The laser system includes highly reflective and partially transmissive mirrors defining the laser cavity and assisting in wavelength discrimination, the birefringent component and Pockels' cell being disposed in series between the lasing medium and the highly reflective mirror.

Abstract: A composite body has a pressed mix base or layer and a thin facing layer formed by casting and bonded to the base and having desired physical properities different from those of the base. This body has utility as a semiconductor substrate with the cast layer providing a substantially defect-free surface for microcircuit formation, or as a cutting tool or the like with the cast layer constituting the hard wear-resistant cutting surface.

Abstract: A multiple ring dipole array comprises a plurality of dipole elements arranged in concentric rings and in a common plane. Each ring has a plurality of circumferentially spaced dipole elements, preferably folded dipoles, having equal lengths and disposed in opposed parallel pairs with elements of each pair spaced by one-half wavelength at center frequency. The elements of adjacent arrays have different lengths selected to provide contiguous or slightly overlapping operating frequency bands, the elements of one ring extending in directions transversely of the elements in the adjacent ring to minimize mutual coupling. Each element is fed by a pair of phase-matched coaxial lines connected to suitable switching circuitry by a hybrid junction. The array has a common phase center over the entire band and so has particular utility as a feed for a parabolic reflector.

Abstract: An improved brazing alloy paste comprises a brazing alloy powder mixed with a ductile metal spacer powder comprised of spherical particles with a predetermined diameter limit and having a higher melting temperature than that of the alloy, both powders being suspended in a gel-like substance. This composite paste produces a brazed joint having a gap with a controlled width and the ductile metal absorbs stresses developed between dissimilar brazed parts as when a tungsten carbide tool bit and the supporting steel shank cool after they are brazed together. The quantity of spherical spacer powder in the mixture is limited to 1-8% by weight of the mixture, preferably 5%, in order to prevent stacking of the spheres and to insure a gap spacing determined by the diameter of the spheres.

Abstract: A conduction cooled solid state laser comprises a laser rod and a pump lamp within a pump cavity in a housing constituting a heat sink, the remote exterior surfaces of the rod and lamp being covered by highly reflective metal foils in intimate contact with those surfaces and backed by a thermally conductive material between the foil and housing that is selected to provide a tailored thermal impedance. The foil acts as a highly efficient reflector and as a thermal contact element between the heat source (rod or lamp) and backing material, the latter, in either solid or fluid form, being selected to provide the desired thermal impedance between the source and sink to optimize component temperatures. The optically reflective and the heat transfer functions of the pumping operation are essentially separate from each other, enabling selection of materials for these respective functions to enhance performance of the laser and substantially simplify its construction.

Abstract: A method of making preforms from brittle metals for brazing or hardfacing consists of pulverizing the metals into a powder, mixing the powder with a liquid vehicle to form a paste, passing the paste through a coated screen having an opening in the coating with the size and shape of the desired preform, depositing the output of the screen onto a substrate and thereby making the preform, heating the preform to evaporate the liquid vehicle, and removing the preform from the substrate. The opening in the screen coating is made by exposing a photo-sensitive film to light through a photographic negative or similar mask having the image of the preform and chemically removing a portion of the film to form an opening having the shape of the preform, the film being mounted on the screen either before or after such exposure.

Abstract: A turnbuckle assembly has a self-contained tension pre-load indicator utilizing internally mounted compact conical spring washers (belleville washers) and a radially projecting movable stem which is rendered immovable when the washers are fully compressed into a flat configuration. The turnbuckle sleeve has an arcuate slot through which the stem extends for accessibility to the operator who determines the attainment of the desired tension pre-load force by the immovability of the stem. The stem is connected to a plane washer disposed adjacent to but slightly axially spaced from the peripheral convex edge surface portions of the end spring washer which when flattened engages the plane washer and prevents it from moving.

Abstract: A power supply for repetitive discharge apparatus such as a laser comprises an unregulated DC source, a primary storage capacitor, a discharge capacitor forming part of the apparatus and an energy feedback circuit between the discharge and storage capacitors operative to return to the storage capacitor energy greater than that required for a predetermined charge level on the discharge capacitor. A switch responsive to the voltage on the discharge capacitor operates a divert excess charging current into resonant charging elements in the feedback circuit for return to the primary storage capacitor. Transfer of the excess charging energy is accomplished nondissipatively to provide highly efficient cycle by cycle voltage regulation.

Abstract: A power supply start-up circuit for apparatus having a storage capacitor comprises a bistable switch with a trigger terminal and connected between one terminal of a DC source and the storage capacitor, a resistor connected across the switch, a trigger capacitor connected to the trigger lead, and a diode connected between the trigger capacitor and the storage capacitor. The trigger lead on the switch is biased by the trigger capacitor which is charged through the diode to the voltage on the storage capacitor. When the storage capacitor is uncharged at start-up, the switch is biased off and charging current from the DC source to the storager capacitor passes through the resistor permitting a "soft" start, i.e., a gradual charging of the storage capacitor. Thereafter charging of the storage capacitor takes place through the switch when biased on by a voltage differential between storage and trigger capacitors.

Abstract: The output power and efficiency of a gas discharge laser is substantially improved by the substitution of neon (Ne) for helium (He) as a buffer in the lasing medium. One embodiment of the invention is a pulsed excimer laser having a lasing gas comprising a mixture of krypton (Kr) and fluorine (F.sub.2). Use of Ne with the KrF excimer lasing medium further enables advantageous utilization of corona wire pre-ionization to initiate the main discharge of this type of laser.

Abstract: A laser electrode assembly comprises an elongated bar having a plurality of longitudinally spaced sockets and is removably secured to a carrier which is anchored to the laser base and has a like number of plugs resiliently press-fitted within the sockets, respectively. Each plug has opposed sides to which are fastened a plurality of outwardly curved resilient fingers extending parallel to the direction of insertion of the plugs into the sockets. Each socket has a width less than the overall width of the plug and finger combination so that the fingers resiliently frictionally engage the bar within each socket. The bar is readily removed from the carrier for maintenance and repair purposes by prying the former from the plugs without necessitating removal of screws or bolts and thereafter passing the bar through the window opening aligned with the discharge gap.

Abstract: A tape transducer comprising an inner conductive strip laminate sandwiched between and totally enclosed by identical outer conductive strip laminates. The inner laminate has an inner conductive strip having opposite sides to which thin dielectric layers are bonded, the layers being electrically charged to form electrets having electrical charges of the same polarity on their outer surfaces. Each outer laminate has a conductive foil with marginal side portions overlying the side edges of the inner laminate and sealed together. The portions of the outer laminates aligned with the inner laminate are capable of simultaneously moving toward and away from the inner laminate for advantageously generating sonic waves in a transmitting mode and for efficiently generating an electrical signal in a receiving mode.

Abstract: In a printed circuit formation process, a positive photoresist layer on a semiconductor substrate surface is exposed to light in a projection exposure system through a transparent liquid-gate which has an index of refraction n.sub.L closer to the index of refraction n.sub.R of the resist layer than is the index of refraction of air. This reduces reflection of light from the resist layers and thus minimizes standing waves in the layer, which waves produce a deleterious layered resist structure and require critical dependence of exposure time on absolute resist thickness. By using photo developer liquid in the gate as the index matching medium together with a reflex viewing system, visual monitoring of the expose/develop process in real time is realized.

Abstract: A method of continuously making a composite tape transducer consisting of the steps of electrically charging dielectric layers on opposite sides of a conductive inner strip to form electrets, applying wider outer laminates symmetrically to opposite sides of the electret-covered inner strip and sealing together the marginal edge portions of the outer laminates to enclose the electret-covered inner strip.

Abstract: A copper base brazing alloy consisting of, in percent by weight, 25 to 40 manganese, 0 to 10 nickel, 0 to 10 iron, 0 to 6 indium and 0 to 10 tin with the combination of tin and indium being not less than 2, and the balance essentially copper, is suitable for brazing cemented carbide to steel in a temperature range 815.degree.-900.degree. C. (1500.degree.-1650.degree. F.). The brazing temperature of these filler alloys are at least 100.degree. F. lower than those of non-precious brazing filler alloys of the prior art used for this application and are considerably less expensive than prior art precious metal brazing alloys currently being used. The resulting cemented carbide to steel joints have high shear strength and good ductility.

Abstract: Apparatus for continuously producing an elongated composite tape transducer having an inner laminate with a conductive dielectric-covered strip and two outer laminates each with a conductive foil comprises two reels containing the outer laminates and one reel containing an inner laminate, a station for electrically charging the dielectric layers on opposite sides of the inner strip, a mold for applying and sealing the outer laminates to opposite sides of the inner laminate to form the composite transducer, and a mechanism for pulling the three laminates through the apparatus. The lead end of the inner strip is electrically grounded. The charging station has two electrodes connected in parallel to a source of high DC voltage and physically positioned to make electrical contact with the dielectric layers, respectively, on opposite sides of the inner strip.