Abstract: Branched polycarbonates are prepared by melt equilibration of aromatic cyclic polycarbonate oligomers with a polyhydric phenol having more than two hydroxy groups per molecule, preferably 1,1,1-tris-(4-hydroxyphenyl)ethane, in the presence of a carbonate equilibration catalyst, preferably tetrabutylammonium tetraphenylborate. In an additional embodimetn of the invention, a linear aromatic polycarbonate is added to the reaction mixture. Branched polycarbonates prepared according to this inventin have high melt strength and high shear sensitivity characteristics and are useful in extrusion and injection molding processing applications and particularly useful in blow molding applications for preparing relatively large articles and panels.

Abstract: A mixture comprised of an alkali chloride solvent and reactants comprised of bismuth sesquioxide, calcium oxide, strontium oxide and copper oxide, or precursors therefor, wherein the reactants are formulated to produce a superconducting reaction product, is heated to melt the chloride solvent in which the reactants then dissolve and react precipitating a Bi-Ca-Sr-Cu-O superconductive material which is comminuted to produce a sinterable powder.

Abstract: Curable compositions containing a reaction product of at least one bisphenol polyglycidyl ether, at least one epoxidized novolak and at least one brominated bisphenol, in combination with a polyphenylene ether and further components including specific catalysts and hardeners, may be used in the preparation of laminates useful as printed circuit boards and having excellent physical and electrical properties.

Abstract: A method and apparatus for indirectly determining rotor position in a switched reluctance motor (SRM) are based on instantaneous flux and phase current sensing. For each phase in a predetermined sequence of phase sensing, which depends on the particular quadrant of machine operation, phase flux and phase current measurements are made during operation in a pair of predetermined sensing regions each defined over a range of rotor angles. Rotor angle estimates are derived from the flux and phase current measurements made during the sensing region for each respective phase. The rotor angle estimates for each phase are normalized with respect to a common reference and then used to generate a rotor position estimate for the SRM.

Abstract: Epoxytriazine-capped polyphenylene ethers are prepared by reaction of a polyphenylene ether with an epoxychlorotriazine such as diglycidyl chlorocyanurate, n-butyl glycidyl chlorocyanurate or mesityl glycidyl chlorocyanurate. The products undergo reaction with nucleophilic polymers such as polyamides and polyesters, to form copolymer-containing compositions which have excellent properties and which find utility as molding compositions and as compatibilizers for blends of similar polymers.

Abstract: An afterburner flameholder for a gas turbine engine having a central diffuser cone, a generally cylindrical outer shell and fuel spray bars between the shell and cone defining an afterburner region is provided, which comprise an annular member with an asymmetric V-shaped cross section. The annular member is adapted to be secured to the engine in the afterburner region with the apex of the V facing upstream in the axial direction toward the fuel spray bars. The annular member has a first and second circular sidewall member each joined at one end forming an apex, the annular member in cross section has unequal length sidewall members. The difference in length between the distal ends of the first and second circular sidewall members is sufficient to cause spanwise vortices shed at the distal ends of the sidewall members to be out of phase when they meet downstream from the flameholder.

Abstract: Protection of a digital multi-pulse speech coder from fading pattern bit errors common in a digital mobile radio channel is accomplished with error detection techniques which are simple to implement and require no error correcting codes. A synthetic regeneration algorithm is employed which uses only the perceptually significant bits in the transmitted frame. Separate parity checksums for line spectrum pair frequency data, pitch lag data and pulse amplitude data are added to each frame of speech coder bits in the transmitter. The bits are then transmitted through a mobile environment susceptible to fading that induces bursty error patterns in the stream. At the receiving station, the parity checksum bits and speech coder bits are used to determine if an error has occurred in a particular section of the bit stream. Detected errors are flagged and supplied to the speech decoder. The speech decoder uses the error flags to modify its output signal so as to minimize perceptual artifacts in the output speech.

Abstract: A method for making cyclic polycarbonate oligomers is provided by converting oligomeric monochloroformate carbonates to the cyclic state. Improvements in materials usage, process control, and product characteristics are obtained.

Abstract: Solvent-resistant resin blends with a wide variety of desirable impact and tensile properties are prepared from a polyphenylene ether having a low proportion of unneutralized amino nitrogen, a mixture of a poly(alkylene dicarboxylate) and a polyarylate, and, optionally, at least one elastomeric polyphenylene ether-compatible impact modifier.

Abstract: A gas probe starter for an electrodeless high intensity discharge (HID) lamp includes a fixed starting electrode for coupling a starting voltage to a chamber which is attached to the outer wall of the arc tube and contains a gas. The gas in the starting chamber, which is preferably at a low pressure relative to that of the arc tube fill, is switched between conducting and nonconducting states corresponding to lamp-starting and normal running operation, respectively. To start the lamp, the starting voltage is applied to the starting electrode, causing a discharge current to flow in the gas chamber which, in turn, results in the capacitive coupling of a sufficiently high voltage to the arc tube in order to initiate an arc discharge therein. After the arc discharge is initiated, the starting voltage is substantially reduced so that the discharge current in the starting chamber is extinguished.

Abstract: A method and apparatus are provided for disposing a polymer film on an irregularly-shaped substrate at relatively high temperatures. In particular, the method and apparatus of the present invention provide a system for the packaging of very large scale integrated circuit chips. The system of the present invention particularly solves problems associated with high temperature processing and problems associated with the highly irregular surfaces that result. Nonetheless, the resultant product is capable of being fashioned into circuit chip systems which are independently testable and which may be reconfigured after testing by removal of the polymer film itself.

Abstract: Apparatus and a method for generating an RF plasma plume wherein hydrogen gas is introduced downstream of the means for injecting plasma gas in order to increase the coupling between the RF coil and the plume and to decrease heat loss to the plasma containment walls.

Abstract: A method for encapsulating microelectronic devices is provided using a heat curable epoxy composition having a monomeric or polymeric diaryliodonium hexafluoroantimonate salt. Curable compositions are also provided as well as encapsulated microelectronic devices.

Abstract: Optical waveguides comprise as core and cladding materials a chemical compound in two different crystalline forms with different indices of refraction. Preferably, the non-linear form is anhydrous and the linear form is a hydrate thereof, whereupon the core material can be prepared by selective heating of the cladding material as by a laser beam. A preferred compound is 4'-dimethylamino-4-methylstilbazolium p-toluenesulfonate.

Abstract: A superconductive switch for a superconductive magnet is bifilarly wound on a bobbin with niobium-tin tape and laminated with stainless steel foil for structural rigidity is provided. The switch is vacuum pressure epoxy impregnated and cooled by copper bus bars which are heat stationed to a cryocooler which is also used to conduction cool the superconductive magnet. The bus bars are also used to introduce a voltage across the switch and the magnet windings which are connected in series with one another to ramp up the current.

Abstract: A piezoelectric ultrasonic array transducer has its individual elements connected to external electronics via a high density interconnect structure which facilitates signal connection and uniformity from array-to-array. The array fabrication process is preferably modified for use with a high density interconnect structure in order to obtain maximum transducer quality.

Abstract: An autonomous active clamp circuit clamps voltage across an inductive load. The clamp closes when the voltage across it exceeds some value substantially above peak line voltage, conducts with a low voltage drop, and opens when the current going through it reaches nearly zero.

Abstract: A polyhydrazine is used to insolubilize a soluble polyimide. Soluble polyimide films on printed circuit boards can be insolubilized in this manner.

Abstract: Solvent-resistant resin blends with a wide variety of desirable impact and tensile properties are prepared from a polyphenylene ether having a low proportion of unneutralized amino nitrogen, a mixture of a poly(alkylene dicarboxylate) and a polyarylate, an aromatic polycarbonate as a compatibilizing agent, and, optionally, at least one elastomeric polyphenylene ether-compatible impact modifier.

Abstract: Redundancy is provided in the data and gate lines of the liquid crystal display device for improved reliability and greater fabrication yield. The data lines in particular are preferably fabricated in a multilayer structure with two conductive layers sandwiching a narrow insulating strip. The presence of the insulating strip permits the upper conductive line to be formed without step jumps which can exhibit a tendency for poor electrical connection. The upper and lower conductive layers of the data line are in contact for the length of the lower data line, contact being made on either side of the narrower insulating strip. Similar redundancy, without the necessity of providing an intermediary insulating layer is also provided for the gate lines. The redundancy provided in the present invention is particularly suitable for fabrication methods employed in thin film FET driven LCD devices.