Abstract:
A satellite imaging system (100) provides successive coregistered images from the perspective of an idealized reference position, such as the nominal geosynchronous orbit position of the satellite. The disclosed satellite (101) is spin-stabilized, and so includes a despun platform (107) which supports a communications subsystem (109), and a spun rotor (111) which supports a sensor (103). The communications subsystem transmits sensor data along a path (115) to a ground station (105). Linear interpolation of real image data as a function of satellite position and imager attitude provides the ideal images. The disclosed invention is also applied to a pointing sensor such as one employed on a three-axis stabilized satellite. The coregistered idealized images coregistered facilitate analysis of weather feature movements and enhance weather forecasting.
Abstract:
An improved laser rod cooling system in which a laser rod (18) is cooled by conducting the heat generated thereby to a flexible, cushioning gel (21) which surrounds and contacts the rod along its length and secures the rod within a fully enclosing support (22). The support is thermally conductive and transparent to the pumping energy from a flashlamp (12). The gel material absorbs differential thermal expansion between the rod and its support to avoid any stresses otherwise exerted on the rod, while the complete surrounding of the rod by the support minimizes thermal gradients within the rod. Thus, a light beam with minimal optical distortion is generated by the laser rod.
Abstract:
An illumination system reflector (18) which provides maximum energy to an aperture (25) with high uniformity and at high efficiencies, the reflector (18) being particularly adapted for use in liquid crystal light valve projection systems. A discharge lamp (34) is utilized in conjunction with an elliptical reflector (18), the axis of the reflector between the primary and secondary focus being tilted at an angle ( theta ) to the lamp axis. The axis of the ellipse (22) is displaced from the lamp axis a predetermined amount (DH), the combination of tilt ( theta ) and displacement (DH) being effective to increase illumination uniformity and efficiency at the aperture (25). Other system parameters, such as throw distance (CTHRO) and cone angle ( alpha ) also affect uniformity and efficiency for a typical design in which the parameters are selected to provide an optimized system being disclosed. A computer program simulation may be utilized for parameter selection. The vertical displacement (DH) parameter is shown to be related to the lamp envelope dimensions.
Abstract:
An RF amplifier arrangement for providing output signals having a controlled frequency distribution and wherein the amplitude and phase of the input signals to an RF amplifier (18) are controlled as a function of the amplitude and phase, respectively, of the output signals from the RF amplifier (18) and also the amplitude of the input signals are adjusted so as to cause the power of the output signal to vary in accordance with a predetermined sequence, whereby such amplitude control of the input signals results in a modified frequency distribution in the energy of the output signals.
Abstract:
An Electron Beam Controlled Switch employing a radial geometry and a Wire-Ion Plasma-Electron gun (WIP E-gun) as an electron source. The switch comprises an inner cylinder (10) that serves as the WIP E-gun cathode, a cylindrical grid (15) that serves as the WIP E-gun anode, an array of fine wire anodes (20) disposed in the WIP E-gun ionization chamber, a foil support cylinder (25) to support the foil windows which also serve as the switch anode, and an outer cylinder (30) which also serves as the switch cathode. The WIP E-gun and ionization chamber (35, 40) is gas filled at low pressure, while the switch cavity (45) is filled with a high pressure gas. A voltage pulse is applied to the wire anodes (20) to ionize the gas in the ionization chamber (35). The ions are extracted through the chamber grid (15) and accelerated through a high voltage to bombard the E-gun cathode (10). The electrons emitted from the ion bombardment are accelerated outwardly through the high voltage, penetrate through the foil windows and into the pressurized gas in the switch cavity (45). The high energy electrons ionize the gas between the switch anode (15) and cathode (10), thereby turning "ON" the switch. In the absence of the electron beam, the switch gas deionizes and switch conduction is quickly extinguished.
Abstract:
A cold-cathode, plasma discharge modulator switch (Fig. 2). A corssed-field discharge plasma (30) supplies charge carriers for the switch. A dc magnetic field (25) is employed to provide a highly localized cusp magnetic field near the cathode (7), so that plasma ionization occurs primarily in the cathode-source grid gap. The region between the cathode (7) and anode (1) is filled with a relatively low pressure gas. A highly transparent control grid (8) with small apertures is closely spaced from the anode (1). The switch is closed through application of positive potential (relative to the plasma) to the control grid (8), and opened through application of negative potential relative to the plasma to the control grid (8). The application of negative potential to the control grid (8) creates an ion sheath around the control grid (8) which permits plasma cut-off to the anode region provided the sheath size is larger than the control grid aperture radius. Upon plasma cut-off, the switch current is interrupted as the remaining plasma in the control grid-anode gap decays. Low pressure operation insures that ionization cannot sustain the plasma in the narrow, isolated control grid-anode gap.
Abstract:
Process for fabricating wraparound solar cells wherein vertical slots are scribed in a semiconductor wafer to initially define the lateral dimensions of the cell. Thereafter, photolithographic masking, etching and diffusion steps are used to define the geometry of a p-n junction of the cell. Then, using lift-off photolithography and a multiple-element metal deposition process, the solar cell grid lines are formed on one surface of the cell and p- and n-type metal contacts are extended around to the opposite surface of the cell. In this manner, the dimensions of the cell can be made less than the diameter of the semiconductor wafer from which it is made.
Abstract:
A highly fluid, solventless heat curable resin is formulated from an admixture comprising a polyglycidyl aromatic amine, a polycarboxylic acid anhydride curing agent, and a curing accelerator. The heat curable formulation exhibits low viscosity and is useful as an encapsulant and insulation for electrical members exposed to high electrical stress. Magnetic coils encapsulated with the cured formulation resist corona discharge at electrical stresses in excess of 2100 volts per mil.
Abstract:
A composite material comprising an ultra-high molecular weight polymer and fibers having lengths of about 0.05 inch (1270 micrometers). This composite is formed by first dispersing the fibers with particles of the polymer in an inert liquid carrier. The dispersion is drawn through a filter which collects the particles and fibers as an intermediate structure in which the fibers are oriented in a quasi-isotropic array and the particles are dispersed throughout this fiber network. The intermediate structure is removed from the filter, dried, compacted, and then compressed at an elevated temperature such that the polymer melts, while the fibers remain unmelted. Upon cooling, there is formed a composite comprising a continuous polymer matrix reinforced with the randomly oriented and intertwined fibers of relatively long length. This material can be formed into articles, such as piston rings or seals, to provide a self-lubricating structure having good wear resistance and creep resistance.
Abstract:
A narrow-band phase shift beamformer system. The outputs from the elements in a transducer array are each divided into two components whose amplitudes are respectively proportional to the sine and cosine of the required phase shift, which are then processed so that the steered beam may be formed by coherent summation. The proportionalities of the respective sine and cosine components are achieved by switched capacitor circuits, which are preferably implemented by LSI circuits, permitting substantial hardware savings and yielding highly accurate component proportionalities.