Abstract: An method and system for laser beam tracking and pointing is based on a conventional position sensing detector (PSD) or quadrant cell but with the use of amplitude-modulated light. A combination of logarithmic automatic gain control, filtering, and synchronous detection offers high angular precision with exceptional dynamic range and sensitivity, while maintaining wide bandwidth. Use of modulated light enables the tracking of multiple beams simultaneously through the use of different modulation frequencies. It also makes the system resistant to interfering light sources such as ambient light. Beam pointing is accomplished by feeding back errors in the measured beam position to a beam steering element, such as a steering mirror. Closed-loop tracking performance is superior to existing methods, especially under conditions of atmospheric scintillation.

Abstract: An oven 1 includes a housing 2 and a hinged cover 3 arranged to be selectively opened and closed. One or more dials 5, buttons 6, and arrow buttons 7 control various functions including activating heat from either the dry heater 10 or the steam heater 12, controlling temperature settings, setting automatic timers, setting displays, setting alarms, and other functions. A circuit or control is used to cycle off the dry heat element 10 when the steam generator 12 requires power to generate steam and to turn the dry heat element 10 back on when the steam generator 12 has cycled off and steam is being introduced into the chamber of the oven 1.

Abstract: A toaster oven features a moving, pivoting heater element to yield improved toasting capability. The toaster oven also cooks food with traditional bake, broil and toast functions, but also has the capability of having an additional heater element that can be positioned closely to the bread rack to give optimum toasting performance. Once the toasting function is completed, the additional heating can be repositioned out of the way, providing increased oven height for cooking bigger sized items.

Abstract: Systems and methods are described for automatically controlling the received power in an optical fiber connected to a free-space optical communications terminal. The system effectively reduces the dynamic range of the received light, enhancing the performance of the communications channel in the face of wide power swings induced by atmospheric scintillation and beam pointing jitter.

Abstract: An method and system for laser beam tracking and pointing is based on a conventional position sensing detector (PSD) or quadrant cell but with the use of amplitude-modulated light. A combination of logarithmic automatic gain control, filtering, and synchronous detection offers high angular precision with exceptional dynamic range and sensitivity, while maintaining wide bandwidth. Use of modulated light enables the tracking of multiple beams simultaneously through the use of different modulation frequencies. It also makes the system resistant to interfering light sources such as ambient light. Beam pointing is accomplished by feeding back errors in the measured beam position to a beam steering element, such as a steering mirror. Closed-loop tracking performance is superior to existing methods, especially under conditions of atmospheric scintillation.

Abstract: Free-space optical (FSO) laser communication systems offer exceptionally wide-bandwidth, secure connections between platforms that cannot other wise be connected via physical means such as optical fiber or cable. However, FSO links are subject to strong channel fading due to atmospheric turbulence and beam pointing errors, limiting practical performance and reliability. We have developed a fade-tolerant architecture based on forward error correcting codes (FECs) combined with delayed, redundant, sub-channels. This redundancy is made feasible though dense wavelength division multiplexing (WDM) and/or high-order M-ary modulation. Experiments and simulations show that error-free communications is feasible even when faced with fades that are tens of milliseconds long. We describe plans for practical implementation of a complete system operating at 2.5 Gbps.

Abstract: A magnetic rotational position sensor including first and second magnets spaced apart to define an air gap and cooperating with one another to generate a magnetic field within the air gap extending along an axis of rotation. At least one magnetic flux sensor is positioned within the magnetic field and is operable to sense varying magnitudes of magnetic flux in response to relative rotational movement between the magnetic field and the magnetic flux sensor about the axis of rotation.

Abstract: A position sensor including a magnetic circuit comprising a magnet having opposite first and second magnetic poles, a first pole piece having a proximal portion positioned adjacent the first magnetic pole and a distal portion positioned adjacent the second magnetic pole to define a first air gap area with a first magnetic field provided adjacent thereto, and a second pole piece having a proximal portion positioned adjacent the second magnetic pole and a distal portion positioned adjacent the first magnetic pole to define a second air gap area with a second magnetic field provided adjacent thereto. A first magnetic flux sensor is disposed within the first magnetic field to sense varying magnitudes of magnetic flux density and to generate a first output signal. A second magnetic flux sensor is disposed within the second magnetic field to sense varying magnitudes of magnetic flux density and to generate a second output signal.

Abstract: A magnetic rotational position sensor comprising a magnetic circuit including a loop pole piece and a magnet, and a magnetic flux sensor adapted to sense varying magnitudes of magnetic flux density associated with the magnetic circuit. The loop pole piece has a peripheral outer wall defining an inner air gap, with the outer wall including an inwardly projecting portion extending into the air gap. The magnet is positioned within the air gap generally opposite the inwardly projecting portion of the loop pole piece. The magnet and the loop pole piece cooperate to generate a magnetic field within the air gap. The magnetic circuit is rotatable about a rotational axis to correspondingly rotate the magnetic field about the rotational axis. The magnetic flux sensor is disposed within the magnetic field to sense a different magnitude of magnetic flux density in response to rotation of the magnetic field about the rotational axis.

Abstract: A non-contacting magnetic position sensor that produces a magnetic field having improved linear characteristics over an extended sensing range. The magnetic position sensor includes a pair of magnets, a pair of pole pieces extending between the magnets and spaced apart to define an air gap, and a magnetic flux sensor operable to sense varying magnitudes of magnetic flux density along the length of the air gap. The pole piece segments form a stepped interface with each of the magnets and cooperate with the magnets to provide a magnetic field having a magnetic flux density that varies in a substantially linear manner along substantially the entire length of the air gap. The magnetic flux sensor is positioned within the magnetic field and is operable to sense a magnitude of the varying magnetic flux density along the air gap and to provide an output signal representative of a position of the magnetic flux sensor relative to the magnetic field.

Abstract: A machine for controlling and eventually eradicating cactus and other succulent plants in farm and ranch pastures and other lands and land uses. This apparatus for mechanically controlling and eradicating cactus and other succulent plants uses a cutter deck on the machine to break off cactus pads near ground level. The tool uses a crushing rail to crush and mangle cactus pads and large portions of other succulents increasing the probability that the plant parts will not reroot. The machine in its preferred embodiment is towed by a tractor or other vehicle. A preferred embodiment includes a ballast rail to increase the weight of the tool and enhance the crushing action and a chain tow bridle to attach the tool to the towing vehicle. Another preferred embodiment includes a loop forming bolt to hold the bridle.

Abstract: A non-contacting magnetic position sensor that produces a magnetic field having improved linear characteristics over an extended sensing range. The magnetic position sensor includes a pair of magnets, a pair of pole pieces extending between the magnets and spaced apart to define an air gap, and a magnetic flux sensor operable to sense varying magnitudes of magnetic flux density along the length of the air gap. The pole piece segments form a stepped interface with each of the magnets and cooperate with the magnets to provide a magnetic field having a magnetic flux density that varies in a substantially linear manner along substantially the entire length of the air gap. The magnetic flux sensor is positioned within the magnetic field and is operable to sense a magnitude of the varying magnetic flux density along the air gap and to provide an output signal representative of a position of the magnetic flux sensor relative to the magnetic field.

Abstract: A magnetic rotational position sensor comprising a magnetic circuit including a loop pole piece and a magnet, and a magnetic flux sensor adapted to sense varying magnitudes of magnetic flux density associated with the magnetic circuit. The loop pole piece has a peripheral outer wall defining an inner air gap, with the outer wall including an inwardly projecting portion extending into the air gap. The magnet is positioned within the air gap generally opposite the inwardly projecting portion of the loop pole piece. The magnet and the loop pole piece cooperate to generate a magnetic field within the air gap. The magnetic circuit is rotatable about a rotational axis to correspondingly rotate the magnetic field about the rotational axis. The magnetic flux sensor is disposed within the magnetic field to sense a different magnitude of magnetic flux density in response to rotation of the magnetic field about the rotational axis.

Abstract: An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.

Abstract: An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.

Abstract: An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.

Abstract: A capacitor is formed of at least two metal conductors having a multilayer dielectric and opposite dielectric-conductor interface layers in between. The multilayer dielectric includes many alternating layers of amorphous zirconium oxide (ZrO.sub.2) and alumina (Al.sub.2 O.sub.3). The dielectric-conductor interface layers are engineered for increased voltage breakdown and extended service life. The local interfacial work function is increased to reduce charge injection and thus increase breakdown voltage. Proper material choices can prevent electrochemical reactions and diffusion between the conductor and dielectric. Physical vapor deposition is used to deposit the zirconium oxide (ZrO.sub.2) and alumina (Al.sub.2 O.sub.3) in alternating layers to form a nano-laminate.

Abstract: A slapper detonator comprises a solid-state high-voltage capacitor, a low-jitter dielectric breakdown switch and trigger circuitry, a detonator transmission line, an exploding foil bridge, and a flier material. All these components are fabricated in a single solid-state device using thin film deposition techniques.

Abstract: A method for preparing plastic injection mold inserts capable of forming a three-dimensional article in a plastic injection molding process. The method includes (a) forming a master mold insert having a recess therein which has a shape which is complementary to at least a portion of the shape of the three-dimensional article; (b) preparing a temporary reverse mold of the master mold insert; (c) positioning a metal gate in the reverse mold adjacent to and in contact with the article form; (d) introducing a hardenable plastic resin into the reverse mold; (e) allowing the resin to harden to form a mold insert; and (f) removing the mold insert from the reverse mold.

Abstract: Swept-wavelength lasers are often used in absorption spectroscopy applications. In experiments where high accuracy is required, it is desirable to continuously monitor and control the range of wavelengths scanned (the scan width). A system has been demonstrated whereby the scan width of a swept ring-dye laser, or semiconductor diode laser, can be measured and controlled in real-time with a resolution better than 0.1%. Scan linearity, or conformity to a nonlinear scan waveform, can be measured and controlled. The system of the invention consists of a Fabry-Perot interferometer, three CAMAC interface modules, and a microcomputer running a simple analysis and proportional-integral control algorithm. With additional modules, multiple lasers can be simultaneously controlled. The invention also includes an embodiment implemented on an ordinary PC with a multifunction plug-in board.