Abstract: An improved plasma controlled millimeter wave (MMW) or microwave (&mgr;W) antenna is provided. A plasma of electrons and holes is photo-injected into a photoconducting wafer. A special distribution of plasma and a MMW/&mgr;W reflecting surface behind the wafer allows the antenna to be generated at low light intensities and a 180° phase shift (modulo 360°) to be applied to selected MMWs/&mgr;Ws.

Abstract: The present invention relates to a material of construction which includes a radar-dispersing metal foam, and to a vehicle to which a radar-dispersing metal foam has been applied. The radar-dispersing metal foam is capable of reducing the radar return from an object by a significant amount over a wide range of radar frequencies. The metal foam has a very low reflectivity to incident radar wave radiation.

Abstract: An improved plasma controlled millimeter wave (MMW) or microwave (&mgr;W) antenna is provided. A plasma of electrons and holes is photo-injected into a photoconducting wafer. A special distribution of plasma and a MMW/&mgr;W reflecting surface behind the wafer allows the antenna to be generated at low light intensities and a 180° phase shift (modulo 360°) to be applied to selected MMWs/&mgr;Ws.

Abstract: A non-mechanical beam deflector forms and scans a beam of millimeter wave (MMW) radiation at a rapid rate. The beam deflector includes a semiconductor body in which a spatially varying density of charge carriers is selectively injected. The injected charge carriers--electrons and/or holes--alter the dielectric constant of the semiconductor body locally and thereby attenuate and reflect incident MMW radiation. The portions of the semiconductor body that do not have carriers injected therein allow the incident MMW radiation to be transmitted. The semiconductor body, modified with a spatially varying density of charge carriers, diffracts the radiation which passes through it into a beam. The beam may be scanned across space through selective control of the injected charge carriers. The diffractive conditions can be rapidly re-configured.

Abstract: A light-modulated photoconductor, exhibiting a variable permittivity, provides the basis for various instrumentation devices and methods. In one embodiment, the light-modulated photocondcutor is used as a dielectric between conductive plates to provide a light-modulated capacitor (photocapacitor). One of the conductive plates may be transparent to facilitate application of the modulating light to the photoconductor. The light-modulated capacitor may be used for numerous applications, such as instrumentation used to, e.g., measure the work function of surfaces during processing or as a non-contact voltmeter. In another embodiment, the light-modulated photoconductor is used as a mirror or lens wherein the index of refraction is optically modulated. Such light modulated lens or mirror assembly may be used as a beam steering device, e.g., a solid state infra-red (IR) beam steering device.

Abstract: In a system and method for producing ultrafine particles and ultrafine fibers of a given source material by evaporating and condensing the material in a gas atmosphere that includes inert gas. A smaller, more narrow size distribution is accomplished by producing the particles and fibers in a microgravity environment in order to reduce particle coalescence caused by convection currents. Particle coalescence also is reduced in an Earth gravity environment by controlling the convection currents. Condensed particles are collected either by providing an electrostatic field or a spatially varying magnetic field or by causing the gas to move through a filter which collects the particles. Nonferromagnetic material fibers are produced and collected by electrodes which produce an electro- static field. Ferromagnetic particles are collected by spatially varying magnetic fields.

Abstract: An apparatus for storing electrically generated heat includes a sealed container holding a bed of fusible heat storage medium, such as an alkali metal hydroxide composition, and having an expansion space above the bed of material to accommodate the medium in its liquid phase. A generally horizontal main electric heating unit is located in the bottom portion of the container for heating the fusible medium above its melting point. A first vertical electric heater is provided in the bed of material in thermal contact with the main heating unit and has its active heating portion extends upwardly from the main heating unit only to the height of the heat storage medium in solid phase. A second vertical electric heater is located in the container in thermal contact with the first vertical heater with the active heating portion of the second heater extending only from the height of the fusible medium in solid phase to the height of the medium in the expanded liquid phase.