Abstract: Disclosed is apparatus for providing for increased heat transfer efficiency f a heat exchanger by separating contiguous fluid conductive channels by means of a flexible sheet fabricated from a piezoelectric polymer. An electrode pattern of predetermined configuration is applied to one or both sides of the piezoelectric sheet and an electrical signal applied thereto in order to set the sheet into a flexual resonance condition whereupon a standing wave pattern is established to not only break up the boundary layer of fluid which adheres to each side of the sheet, but also minimizing the thickness of the laminar sub-layer.

Abstract: A force rate sensor for providing a signal proportional to the time rate of hange of an applied force.

Abstract: Apparatus and method are described for fabricating a long life cold cathode lectron beam semiconductor device (EBS). Fabrication is given of a vacuum tube structure capable of sustaining sufficiently high vacuum over extended time to prevent poisoning of the cold cathode and steps are give for growth of a plural tip cold cathode structure.

Abstract: A variety of technologies have been applied in the development of a bonded rid cathode. Erosion lithography is used for making the fine-detail grid structure, combining air erosion and lithographic techniques. To obtain openings of the order of 0.001 inch (one mil) or smaller, a nozzle with a high aspect ratio exit opening is used, and the cathode grid structure is scanned. A photo resist in which the grid pattern is developed is used over the molybdenum or tungsten grid film. The metal film is removed from the grid openings by chemical etching. The photo resist over the metal grid is used as a composite mask for removing the BN insulation in the openings by erosion with Al.sub.2 O.sub.3 powder from the special nozzle on the air blast gun.

Abstract: Disclosed is an in-band, non-sampling, real time VHF radio relay or signal epeater for use in two-way, multi-hop remote sensor data links. Each signal repeater comprises a transceiver which includes interference cancellation circuits for preventing the high level signal produced by the radio repeater's transmitter section from desensitizing the low noise RF amplifier circuitry incorporated in the front end of the radio repeater's receiver section. Such apparatus is utilized to implement a remote sensor data collection network consisting of a plurality of subject radio repeaters and several sensors normally arranged in groups. The data which flows over the relay network can either originate at the sensors and flow to a read out station or it may originate at the read out station and flow to the sensors. Sensor originated information may be either digital or analog, or both, while read-out station originated information is digital only. The relay operates with either analog or digitally-modulated signals.

Abstract: An electronic detection system for detecting intruders employs a transmisn line as a sensing element. In one embodiment the transmission line is a modified surface-wave transmission line, for example, a Goubau line which is positioned about the perimeter of the area to be protected. An intruder in the field of the line causes an RF reflection back toward the source, which reflection may be detected by Doppler range-gating techniques. In other embodiments of the invention, the transmission line is an insulated, twisted wire pair or a deformable transmission line. In some instances, the transmission line may be replaced with an active or passive pressure line.

Abstract: An electronic detection system for detecting intruders employs a transmisn line as a sensing element. In one embodiment the transmission line is a modified surface-wave transmission line, for example, a Goubau line, which is positioned about the perimeter of the area to be protected. An intruder in the field of the line causes an RF reflection back toward the source, which reflection may be detected by Doppler range-gating techniques. In other embodiments of the invention the transmission line is an insulated, twisted wire pair or a deformable transmission line. In some instances, the transmission line may be replaced with an active or passive pressure line.

Abstract: A high power, broadband, active transmitting antenna for operation in the frequency range below 1 GHz which is in the order of 0.15 wavelength in electrical size. The relatively small antenna is coupled across an electron bombarded semiconductor device in the form of a diode which is penetrated by high energy electrons from an electron gun modulated with the RF signal to be transmitted.

Abstract: A harmonic frequency generator responsive to an input signal of frequency f hich changes slowly in both frequency and amplitude and characterized in that (1) the output signal (harmonic) amplitude remains proportional to the input signal amplitude and (2) the output frequency nf of the output signal consists soley of one integral (n>1) multiple of the input signal frequency.

Abstract: A system for making emission measurements of RF electromagnetic energy, s as interference, over a relatively wide bandwidth without tuning or scanning and without the knowledge of the specific signal characteristics of the emission under consideration by receiving and detecting the emission in the circuit configuration where the ratio (r) of the impulse signal response to CW signal response is a predetermined function of the pre-detection bandwidth (B.sub.I) and the post-detection bandwidth (B.sub.O). More particularly, the impulse to CW signal response ratio is controlled according to the expression r=1/(2B.sub.O B.sub.I -B.sup.2.sub.O).sup.0.5. Such a relationship will cause the response to all other types of emission to fall intermediate the impulse and CW signal response.

Abstract: A circuitless particle beam device for relatively high frequency amplifier r oscillator applications that eliminates the requirement for an internal RF slow wave structure. A circularly polarized RF energy wave propagates on a relatively high density particle beam within an oversized waveguide and interacts with the beam which exhibits a relatively high dielectric constant. The high density beam acts as an active dielectric waveguide serving the dual purpose of a slow wave circuit and amplification source, and accordingly guides and amplifies the RF energy when a condition of beam and wave synchronism is met.

Abstract: Disclosed is an array of avalanche diodes and its method of manufacture which results in plural pairs of series connected mesa-etched avalanche (TRAPATT) diodes being selectively connected in parallel by metallized air bridges for increasing the impedance level and thereby the peak and average power level available from microwave oscillators and amplifiers configured therefrom. The various series connected diodes are placed in near proximity to respective neighboring diode pairs to reduce parasitics but at the same time the spacing is made sufficiently large to prevent thermal spreading of one diode pair to overlap that of the adjacent diode pair. The metallized air bridges in addition to providing a low inductance interconnection, provide an integrated heat capacitance which is necessary for high power operation.

Abstract: The high pressure furnace comprises a cylindrical pressure vessel with fr and rear pressure closures. An electrical heating element is supported within the interior of the pressure furnace. The front closure supports a relatively thin-walled inner container opening only to an aperture in the front closure. A small closure plugs the aperture. A reaction frame secures the various closures. Blanket gases are introduced into the furnace chamber and process gases into the process chamber defined by the interior of the inner container. Means are provided for minimizing the pressure difference across the inner container to enable it to maintain its original shape.

Abstract: A collector for use in a travelling wave tube includes a central metallic re that has a peripheral ceramic insulator with the central metallic core having a plurality of circumferentially spaced primary slots extending inwardly from the periphery and an equal number of secondary slots extending perpendicular to the primary slots adjacent the periphery of the electrode. The primary slots define a plurality of fingers and the secondary slots act as hinges for the fingers.

Abstract: To prevent the anode wire which runs along the axis of the tube from vibrng at the end adjacent the window, a ceramic cup has a flat surface sealed to the inside of the window, and the end of the anode wire is captured within an opening of the cup.

Abstract: A generally flat, relatively thin AT-cut piezoelectric resonator element structured to minimize the force-frequency effect when mounted and energized in a housing. The resonator is in the form of an equilateral hexagon with the X crystallographic axis of the crystal passing through one set of opposing corners with mounting being effected at an adjacent set of corners respectively .+-.60.degree. away from the X axis which thereby results in a substantially zero frequency shift of the operating frequency.

Abstract: An improved hermetically sealed container is disclosed having a receptacle ith at least one opening for mounting a desired element in the opening, a closure element covering each opening, a metallized seal between the closure element and the receptacle with the metallized seal peripherally surrounding the opening and hermetically sealing the closure element to the receptacle, and a sealing deposit electrolytically applied to the outer surface of the metallized seal. A method of making such a hermetically sealed container is also disclosed.

Abstract: Methods and apparatus for contactless, non-destructive resistivity measurnts on semiconducting crystalline material, for example gallium arsenide. The material to be tested is formed into a disc which is supported within an air gap. The holder for the disc is such as to support the disc only about its outer edges; thus, the disc is free to vibrate piezoelectrically. A measuring circuit connected to the electrodes, which establish the air gap, applies an alternating electric field in the air gap which causes the crystal to vibrate. By adjusting the frequency of excitation, resonance may be established in the crystal and by comparing the current drawn through the air gap with graphs previously established for material of the type under test, the resistivity of the disc can be determined.

Abstract: Disclosed is a capacitive voltage divider drive circuit for electroluminent matrix displays comprised of, for example, thin film electroluminescent capacitance type elements. The drive circuit for each display element, which exhibits a relatively low capacitance, includes a relatively large series connected capacitor which couples a drive voltage thereacross upon the closure of a first switching element. Due to voltage divider action, a relatively greater portion of the drive voltage appears across and energizes the display element by exceeding its threshold voltage. Additionally, another relatively large capacitor is coupled in parallel with the display element upon the closure of a second switching element which, again due to voltage divider action, reduces the drive voltage thereacross below its energizing threshold level to deenergize it.

Abstract: A system for providing a simulated target and scene on a projector screen, wherein a first infrared (IR) detector senses reflected IR light from the screen to indicate an associated simulated weapon has hit the target and a second IR detector mounted in proximity to said first detector enables automatic sensitivity adjustment to different brightness backgrounds.