Abstract: Polyphenylene ethers are capped by reaction in the melt, with application of vacuum, with at least one trimellitic anhydride salicylate, ester, preferably the 4-(phenyl salicylate) ester. The preferred melt processing method is extrusion with vacuum venting. By this method, the polyphenylene ether is capped with reactive dicarboxylate groups and also with salicylate groups, improving its thermal stability. The capped polyphenylene ether is capable of forming copolymers with polyamides, and said copolymers are useful as compatibilizers for polyphenylene ether-polyamide blends.

Abstract: A heat curable composition is provided which is useful for encapsulating microelectronic devices using a heat curable epoxy composition having a diaryliodonium hexafluoroantimonate salt as a catalyst in combination with an effective amount of a free radical generating aromatic compound as a cocatalyst.

Abstract: A mold structure including layers with different physical properties is used to provide hot surface during molding. The use of a thin layer of low thermal conductivity covered by a smooth skin layer prevents quick cooling of the surface of the pre-heated plastic to be molded. The plastic surface remains molten and flows to fill the mold during press closing, resulting in smooth surfaces even when fiber reinforced plastics are used.

Abstract: This invention discloses an optical fiber connect/disconnect for power lasers. The connect/disconnect should allow a laser/fiber user to quickly interface fiber injection input and fiber output couples while providing electrical feedback and optical alignment. The connect/disconnect also offers an electrical feedback which should provide the user with operating parameters of the input and output couplers and/or the connect/disconnect assembly.

Abstract: An improved high order interpolative oversampled (sigma delta) analog-to-digital converter network including a plurality of cascade-coupled integrator stages is formed on a single integrated circuit chip in a manner that conserves power and chip area. Each integrator stage includes a differential amplifier, at least one input capacitor and at least one feedback capacitor. The power dissipation and occupied chip area are minimized by down-sizing the chip area occupied by the capacitors and differential amplifiers (op amps) in all but the first integrator stage. The high gain of the first integrator stage makes the noise contribution of subsequent integrator stages negligible so that the higher noise of the subsequent integrator stages is tolerable.

Abstract: The present invention is an apparatus for performing a joining operation to couple a first component to a second component. One embodiment of the present apparatus includes means for aligning the first component and the second component so that a first portion of the first component is aligned with a first portion of the second component, means for heating the first component so that a melt is formed at the first portion of the first component, and means for forcing the first portion of the second component into the melt so that when the melt solidifies, the first component and the second component are bonded. In the exemplification embodiment, the heating means is an Nd:YAG laser source which emits at least a first laser beam which impinges upon one of the components.

Abstract: A dual-permeability magnetic core structure is provided for use in small, high-frequency inductors and transformers. The dual-permeability core encloses a winding window containing planar windings and comprises high-permeability and low-permeability sections positioned to produce a highly uniform, or uniformly varying, magnetic field on the winding surfaces. The dual-permeability core products low winding losses and a low AC-to-DC resistance ratio. Fabrication of the dual-permeability core involves a method of controlling the permeability of a magnetic material and a methd of combining structures of two different permeability values.

Abstract: An ultrasonic imaging system has a probe with an even-numbered plurality of N of transducer elements, with one transducer element being present in each of a like plurality N of signal-processing channels, and with successive ones of the transducers polarized in alternating directions. The transducers require channel excitation drive signals which are either a positive-polarity pulse or a negative-polarity pulse, with signal polarity being dependent upon the polarity of the transducer in the particular channel. The processed outputs of each odd channel is connected directly to an associated input of a coherent summer while the processed output of each even channel is individually amplitude-inverted before connection to an associated summer of input. The summation means output is the sum of all channel transducer outputs, with suppression of any common-mode signal appearing anywhere in the system channels, from the transducer to the summation means inputs.

Abstract: A closed-loop control system for a Class-D power amplifier circuit, having a variable output resonant circuit impedance, maintains high-efficiency operation by using the phase angle between the resonant load voltage and current to control tuning of the resonant circuit. The resonant load circuit voltage and current are supplied to a phase detector for detecting the phase angle therebetween and for generating a voltage proportional thereto. The output voltage from the phase detector is compared to a reference voltage by an error amplifier. The resulting error voltage is employed as the input signal to control circuitry for tuning the output resonant circuit. Such a control system is suitable for maintaining high-efficiency operation of an electrodeless high intensity discharge lamp system.

Abstract: A gradient current speed-up circuit, for use in a higher-speed NMR imaging system having an associated gradient coil, has a gradient power amplifier receiving an input analog signal controlling amplifier output current, and a transformer having a primary winding and a pair of secondary windings connected in series with the amplifier output and the coil. Semiconductor switching elements selectively connect the primary winding between first and second potential sources, and are turned on and off in selected patterns to cause a current to be suddenly applied to, and removed from, flow through the associated gradient coil; the amplifier output current is changed with the gradient coil current lags behind an amplitude commanded by a master input signal.

Abstract: Each cell of a liquid crystal display comprises a pixel electrode, a primary field effect transistor for transferring electrical signals from one scan line and one data line to the pixel for conversion to an optical signal and at least one auxiliary field effect transistor for transferring signals from a scan line adjacent to the one scan line and from the one data line to the pixel when the primary field effect transistor is defective. The auxiliary FET gate electrode is electrically isolated from the adjacent scan line when the primary FET is not defective and may be connected to the adjacent scan line by activating a laser-fusible link if the primary FET is defective. Redundant scan line crossovers and redundant data line crossover are provided, with each redundant crossover having an open circuit that may be closed by a laser-fusible link to create a shunt around a selected scan and data line crossover location, if the scan line and data line are shorted together at that crossover location.

Abstract: A focus spot size controller for a variable depth triangulation ranging system, the ranging system including apparatus for emitting light beam to be focused onto an object, light sensitive apparatus, lens apparatus for imaging reflected light onto said light sensitive apparatus, and apparatus for calculating system geometry and range from signals received from the light sensitive apparatus. The present invention includes a focus spot size controller for receiving the light beam from the light beam emitting apparatus and for focusing the light beam into a focused spot on an object, the controller positioning the focused spot axially to achieve sufficient focus spot size for imaging.

Abstract: A method for controlling process conditions in a continuous skull nozzle process is provided wherein one or more process parameters are controlled to maintain the operation of the process within a process window derived using integral solutions and expressed in terms of dimensionless parameters. The process window defines a range of values for the controllable process parameters within which a steady state solidified skull will be maintained and outside of which a steady state solidified skull will not be maintained. A pressure differential between the inside of a crucible holding the melt and outside of the crucible is one process parameter which is controlled to adjust the melt discharge flow rate to maintain operation within the process window.

Abstract: Thermomechanical processing treatments for powder compacts formed from powdered superalloy compositions having a volume fraction of gamma prime greater than 35 percent are disclosed. Isothermal forging within critical ranges of strain rate and temperature is followed by supersolvus annealing and slow cooling treatments. An enlarged grain structure about 50 to 60 microns in size is produced that improves resistance to fatigue crack propagation in the superalloys.

Abstract: An image signal processing system DPCM encodes the signal, then Huffman and run length encodes the signal to produce variable length code words, which are then tightly packed without gaps for efficient transmission without loss of any data. The tightly packing apparatus has a barrel shifter with its shift modulus controlled by an accumulator receiving code word length information. An OR gate is connected to the shifter, while a register is connected to the gate. Apparatus for processing a tightly packed and decorrelated digital signal has a barrel shifter and accumulator for unpacking, a Huffman and run length decoder, and an inverse DCPM decoder.

Abstract: A method for controlling the dimension of a reinforced metal matrix composite structure is taught. The structure is annular and the method is to render the structure non-round where the initial structure is essentially round. The cure of the essentially round condition is accomplished by forming a solid mandril very slightly smaller in dimensions than the final dimensions sought for the structure. The essentially round composite ring is forced onto the non-round mandril and heated to the relaxation temperature of the matrix. Because the mandril has a higher thermal coefficient of expansion than the matrix, the method is effective in forming an essentially round structure into a non-round configuration.

Abstract: A method for determining the length of data strings on a distributed processing system is disclosed. The method assigns a sequential position value to each element in the string, the position value zero being assigned to the true head element. The sequential position value of each element exceeds by one the sequential position value of the immediately succeeding element in the string. After identification of the tail element of the string, the sequential value of the tail element is incremented by one to yield the string length.

Abstract: A scanning spectral-analysis micro-probe subsystem, for a surface imaging system, utilizes a micro-probe to detect the precise position of a point on a sample object surface having surface dimensions changing responsive to surface absorption of incident radiation from a modulated radiation source. The modulated incident radiation causes the sample region dimensions, in the vicinity of the micro-probe, to be modulated, so that the micro-probe detects this dimensional modulation, with a detected modulation strength directly proportional to the incident radiation absorption.

Abstract: A starting circuit for an electrodeless high intensity discharge lamp comprises a high efficiency power supply for providing a radio frequency signal to a starting probe disposed proximate the arc tube of the lamp. The power supply may comprise either a Class-D or Class-E power amplifier having an output resonant circuit tuned to a substantially higher frequency than the operating frequency of the signal provided to the excitation coil by the lamp ballast to ensure minimal interaction between the starting circuit and the ballast. The output resonant circuit includes an inductance coupled in series with a capacitance that preferably comprises the capacitance between the excitation coil and the starting probe. After initiating the arc discharge, the starting circuit is deactivated.

Abstract: A two dimensional mosaic scintillation X-ray or Gamma ray detector has many mosaic elements. A reflecting means, e.g., an epoxy with TiO.sub.2, is disposed between the elements to reduce optical cross-talk. The elements have wide narrow ends and either the wide ends or the narrow ends can receive the incident X-rays. A photodetector is optically coupled to the remaining ends either by being directly secured thereto or by way of a lens or optical fibers. The detector has communicating wide and narrow grooves and can be made by first forming the wide grooves from a first side and then forming the narrow grooves from the second side.