Abstract: A particular wavelength may be eliminated from the spectrum of a randomly polarized thermally radiative scene by a quarter-wave polarizer and a dielectric dispersive mirror angularly positioned at the Brewster angle for the particular wavelength. The scene radiation is linearly polarized in the plane of incidence of the mirror and the particular wavelength of the scene is transmitted. The other wavelengths of the scene whose indices of refraction are dispersive, i.e., different from the particular wavelength, are reflected and directed to a photodetector, some other radiative detecting device, or a human eye. The invention can thus provide protection from a laser or other high-power optical emitter when used as a counter-measure in a thermally radiative scene.

Abstract: A far-infrared image is directed onto a transducer having a planar array of absorbing discs on one side. The discs are supported by a thin membrane ich expands and bulges as the discs heat up. The discs thus change their spacing with respect to a partially reflective mirror. The nominal spacing between the discs and mirror is about 1/4 wavelength of the infrared radiation, such that absorption is enhanced. The mirror is supported on a transparent substrate through which visible or near-infrared light is shown, and carries a perforated mask atop an insulating layer and in registration with the discs. The mirror/discs thus establish a Fabry-Perot cavity for the visible or near-infrared light, whereby a visible or near-infrared image may be observed or detected as the various discs establish various spacings in accordance with incremental variations in the infrared image. An electrostatic field is established between the mirror and the shield by a voltage source.

Abstract: A power limiter is provided consisting of two cells of optically transparent material having a low index of refraction, but a large third order susceptibility to electric polarization. The input cell has a positive susceptibility which self-focuses intense radiation beams (i.e., laser beams) and the output cell has a negative susceptibility which scatters the even more intense self-focused beam by self-defocussing.

Abstract: An aiming point system and technique for defining the aiming point of a d collection receiver used by an operator. A data receiver is directed to the aiming point for collecting and amplifying sub-audio signals emitted from rotary aircraft. The sub-audio signals are converted to audible signals by a voltage to frequency converter. The aiming point is readjusted manually or automatically in response to the sub-audible strength of the audible signal to obtain at least a substantial proportion of the target signature of the rotary type aircraft. The data collection receiver may include binoculars with a silicon photo detector and pre-amp within one of the binocular eyepieces.

Abstract: A nanoporous semiconductor material and fabrication technique for use as rmoelectric elements. Starting precursors are mixed in solution so as to thoroughly dissolve in solution which is then reduced. A second phase may be added in solution to provide nanoinclusions which may be subsequently removed. A nanoporous semiconductor is formed whereby lattice thermal conductivity is greatly reduced, due to enhanced phonon scattering on the order of 10 W/cm.multidot..degree.K. The nanoporous semiconductor material may be used as the n- and p- legs in a Peltier couple utilized for a thermoelectric cooler, a cryogenic cooler, thermoelectric power generator, or a thermoelectric heat pump.

Abstract: A trilaminar semiconductor device is placed at an intermediate focus is an optical instrument having a sensitive photodetector. The layers of the device are successively in the form of a two-photon absorber, a sacrificial layer, and a multiple quantum well. The composition of the semiconductor is varied in the layers to achieve the desired bandgap and function.

Abstract: Incident radiation is focussed by a lens into a non-linear optical material whose index of refraction increases with increased radiation intensity. For normal radiation, the radiation freely passes through the nonlinear optical and an optically-switchable material to an other lens. This other lens directs the radiation onto a photodetector. High-intensity radiation, however, is self-trapped in the nonlinear material to form a columnar beam which falls on the optically-switchable material, causes this material to switch, and is reflected thereby.

Abstract: A chemical protective fabric for use in garments worn by persons in a cheally hostile environment comprises a layer of felted foam impregnated with superactivated carbon, a polyurethane emulsion binder for bonding the superactivated carbon to the foam, a first stretchable material layer bonded to the layer of foam on a first of the major surfaces thereof, and a second stretchable material layer bonded to the layer of foam on a second of the major surfaces thereof.

Abstract: A negative ion source with an automatic control system wherein a low power igh frequency discharge is used to sustain a high power low voltage dc discharge in a chamber that magnetically confines the plasma produced. The low power high frequency discharge and the high power low voltage direct current discharge are two discharges along with the gas flow rate which are independently adjusted, automatically, so that the conditions for optimum production of vibationally excited hydrogen molecules consistent with the production of maximum H.sup.- output current is obtained and maintained. This chamber is separated by a magnetic filter field from a second chamber which maintains the low temperature plasma in the second chamber necessary for the optimum production of H.sup.- ions by the process of dissociative attachment, utilizing the vibrationally excited molecules produced by the first chamber.

Abstract: The invention is an insensitive energetic composition that is an explosive and the related articles and systems. The composition has HMX or RDX as an energetic filler, a nonenergetic binder and an energetic plasticizer. The plasticizer is a nitrato-nitramine or a liquid nitrate ester. This provides a matrix with a glass transition temperature below minus 45 degrees Centigrade. In another variation, the composition can also include aluminum powder. Generally, the materials have particularly strong blast effects.

Abstract: In order to protect a delicate photodetector from high-intensity radiation, such as from a laser, a device for limiting optical power to the detector is interposed between the radiation and the detector. This device has an optical interface that totally reflects high-intensity radiation, but which freely transmits normal (low intensity) radiation to the detector. The interface is between two optical materials, one with a linear index of refraction with respect to radiation intensity, and the other with a non-linear index. At low intensity radiation levels, the two materials have the same indices of refraction, and such radiation is freely transmitted through the interface, but with high-intensity radiation, a mismatch of indices of refraction allows total reflection at the interface.

Abstract: A new optical diode is disclosed that permits unidirectional transmission of light, the direction of transmission depending on the direction of incidence. The diode comprises a stack of alternating layers of a low-index material and a high-index material. The layers are arranged within the stack such that there is spatial anisotropy of optical pathlengths in the stack and at least the low-index layers or the high-index layers have an optical nonlinearity, either inherently or by doping. At sufficiently high incident intensifies and appropriate wavelengths, such a diode exhibits partial transmission of input light incident from one direction while reflecting almost totally input light incident from the opposite direction.

Abstract: An apparatus and method for producing a selectable effects explosively fod penetrator warhead having the ability to defeat either single armored targets or a multiplicity of lightly armored targets.

Abstract: A Reduced Radar Cross-Section RF Seeker Front-End interrogates a potential arget by issuing interrogation radiation toward the target and receiving and analyzing a portion of the radiation that reflects back from various surfaces of the targeted object while, at the same time, the Front-End reduces the likelihood of its own discovery by the enemy. The Front-End accomplishes the reduction by absorbing radiation directed toward it by an enemy radar or anti-tactical missile rather than allowing the radiation to be reflected back. Such absorption greatly diminishes the availability of signature reflection that belligerents rely on to identify hostile forces on the battlefield.

Abstract: A solar-powered, illuminated aircraft warning marker for connection to suspended cables and overhead transmission lines includes a polygonal housing having a plurality of light elements attached to different sides of the housing. The warning marker includes solar cells, storage batteries and electrical circuit apparatus for selectively illuminating the light elements during low ambient light and nighttime conditions.

Abstract: The conversion of carbon-carbon of a composite material at the surface to licon carbide-hybridized carbon-carbon in accordance with the method of invention is accomplished by reacting the carbon fibers and matrix with silicon monooxide at elevated temperature from about 1500.degree.-1700.degree. C. The conversion of bulk graphite or carbon-carbon composite materials is achieved in 30-60 minutes at 1700.degree. C. With conversion the density is increased from the density of carbon of 1.45 grams/cc to that of silicon carbide of 3.21 grams/cc. The method of reaction in the vapor phase of silicon monooxide with the carbon-carbon bond releases a C atom in exchange for the Si atom with a release of CO from the composite material. Photomicrographic studies indicates a depth of conversion from about 50 to 100 mils.

Abstract: The device of this invention is used to detect small quantities of liquid emical agents in certain pesticides on the basis of the heat reaction between the liquid agent and a chemical oxidant such as sodium or calcium hypochlorite. The detecting device consists of a thin film of resistance heat sensitive element on top of which porous or fibrous substrate material is mounted. This substrate is impregnated with the oxidant material. As a liquid agent contacts substrate it permeates through the substrate and reacts with the oxidant and generates heat. The output volume from the thin film resistance element increases correspondingly. The time from agent contact until this signal is observed as tested is less than one (1) second. The method is directed to the contacting of the liquid agent against the surface, wherein it permeates through the substrate and reacts with the oxidant and generates heat which change in heat is detected by the detecting device.

Abstract: A liquid propellant igniter uses axially aligned ring electrodes separated y high strength ring-shaped insulators and a high-voltage electrode assembly to provide reliable electrical discharges for initiating and igniting a propellant.

Abstract: A process is described which will autonomously map an area, autonomously rch for concentrations of depleted uranium, automatically record the intensity of radiation, and record the exact map location in real time.

Abstract: Remote telemetry control in the testing of multiple projectiles such as rets, simultaneously fired, in an environment requiring extremely low power dissipation in the inactive state and experiencing extremely high-G accelerations during launch. On-board battery charging, battery and telemeter conditioning and telemeter control are remotely effected in a highly reliable manner through interfacing a portion of which is on board each projectile and another portion of which is remote from the projectiles and also remotely controlled for safety reasons. The aforementioned on-board functions are prioritized to accomplish first the charging and conditioning requirements, whereby telemeter activation during same is prevented, and the control signals governing charging, conditioning and telemeter operation are electronically isolated to prevent spurious activation. Electronic switching circuitry is incorporated to protectively ensure deactivation of the telemeter during higher priority operations.