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Reflection mass spectrometry technique for monitoring and controlling composition during molecular beam epitaxy (open access)

Reflection mass spectrometry technique for monitoring and controlling composition during molecular beam epitaxy

This invention is comprised of a method for on-line accurate monitoring and precise control of molecular beam epitaxial growth of Groups III-III-V or Groups III-V-V layers in an advanced semiconductor device incorporates reflection mass spectrometry. The reflection mass spectrometry is responsive to intentional perturbations in molecular fluxes incident on a substrate by accurately measuring the molecular fluxes reflected from the substrate. The reflected flux is extremely sensitive to the state of the growing surface and the measurements obtained enable control of newly forming surfaces that are dynamically changing as a result of growth.
Date: August 15, 1990
Creator: Brennan, T. M.; Hammons, B. E. & Tsao, J. Y.
System: The UNT Digital Library
Separation of Metals by Supported Liquid Membranes (open access)

Separation of Metals by Supported Liquid Membranes

A supported liquid membrane system for the separation of a preselected chemical species within a feedstream, preferably an aqueous feedstream, includes a feed compartment containing a feed solution having at least one preselected chemical species therein, a stripping compartment containing a stripping solution therein, and a microporous polybenzimidazole membrane situated between the compartments, the microporous polybenzimidazole membrane containing an extractant mixture selective for the preselected chemical species within the membrane pores is disclosed along with a method of separating preselected chemical species from a feedstream with such a system, and a supported liquid membrane for use in such a system.
Date: December 31, 1990
Creator: Takigawa, Doreen Y.
System: The UNT Digital Library
Method for Improving the Growth of Cadmium Telluride on a Gallium Arsenide Substrate (open access)

Method for Improving the Growth of Cadmium Telluride on a Gallium Arsenide Substrate

A method for preparing a gallium arsenide substrate, prior to growing a layer of cadmium telluride on a support surface thereof. The preparation includes the steps of cleaning the gallium arsenide substrate and thereafter forming prepatterned shapes on the support surface of the gallium arsenide substrate. The layer of cadmium telluride then grown on the prepared substrate results in dislocation densities of approximately 1{times}10{sup 6}/cm{sup 2} or less. The prepatterned shapes on the support surface of the gallium arsenide substrate are formed by reactive ion etching an original outer surface of the gallium arsenide substrate and into the body of the gallium arsenide substrate to a depth of at least two microns. The prepatterned shapes have the appearance of cylindrical mesas each having a diameter of at lease twelve microns. After the mesas are formed on the support surface of the gallium arsenide substrate, the substrate is again cleaned.
Date: December 31, 1990
Creator: Reno, John L.
System: The UNT Digital Library
Improved morphology in electrochemically grown conducting polymer films (open access)

Improved morphology in electrochemically grown conducting polymer films

A conducting polymer film with an improved space filling is formed on a metal electrode surface. A self-assembling monolayer is formed directly on the metal surface where the monolayer has a first functional group that binds to the metal surface and a second chemical group that forms a chemical bonding site for molecules forming the conducting polymer. The conducting polymer is then conventionally deposited by electrochemical deposition. In one example, a conducting film of polyaniline is formed on a gold electrode surface with an intermediate monolayer of p-aminothiophenol.
Date: December 31, 1990
Creator: Rubinstein, I.; Gottesfeld, S. & Sabatani, E.
System: The UNT Digital Library
Passive decay heat removal system for water-cooled nuclear reactors (open access)

Passive decay heat removal system for water-cooled nuclear reactors

This document describes passive decay-heat removal system for a water-cooled nuclear reactor which employs a closed heat transfer loop having heat-exchanging coils inside an open-topped, insulated evaporator located inside the reactor vessel, below its normal water level, in communication with a condenser located outside of containment and exposed to the atmosphere. The heat transfer loop is located such that the evaporator is in a position where, when the water level drops in the reactor, it will become exposed to steam. Vapor produced in the evaporator passes upward to the condenser above the normal water level. In operation, condensation in the condenser removes heat from the system, and the condensed liquid is returned to the evaporator. The system is disposed such that during normal reactor operations where the water level is at its usual position, very little heat will be removed from the system, but during emergency, low water level conditions, substantial amounts of decay heat will be removed.
Date: December 31, 1990
Creator: Forseberg, C. W.
System: The UNT Digital Library
Water and UV degradable lactic acid polymers (open access)

Water and UV degradable lactic acid polymers

A water and UV light degradable copolymer of monomers of lactic acid and a modifying monomer selected from the class consisting of ethylene and polyethylane glycols (PVB 6/22/90), propylene and and polypropylene (PVB 6/22/90) glycols, P-dioxanone, 1, 5 dioxepan-2-one, 1,4 -oxathialan-2-one, 1,4-dioxide and mixtures thereof. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide wherein the high molecular weight polyethylene oxide is present in the range of from about 2% by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures thereof to an agricultural site is also disclosed.
Date: June 26, 1990
Creator: Bonsignore, P. V. & Coleman, R. D.
System: The UNT Digital Library
Production of aluminum-26 (open access)

Production of aluminum-26

This invention is a method of producing Al-26 from potassium chloride by exposing it to a proton beam in order to break potassium and chlorine atoms into smaller pieces, which include Al-26. The Al-26 is isolated from the potassium chloride and substances produced by the beam by means of extraction and ion exchange.
Date: December 31, 1990
Creator: Steinkruger, F. J. & Phillips, D. R.
System: The UNT Digital Library
Process of making cryogenically cooled high thermal performance crystal optics (open access)

Process of making cryogenically cooled high thermal performance crystal optics

A method for constructing a cooled optic wherein one or more cavities are milled, drilled or formed using casting or ultrasound laser machining techniques in a single crystal base and filled with porous material having high thermal conductivity at cryogenic temperatures. A non-machined strain-free single crystal can be bonded to the base to produce superior optics. During operation of the cooled optic, N{sub 2} is pumped through the porous material at a sub-cooled cryogenic inlet temperature and with sufficient system pressure to prevent the fluid bulk temperature from reaching saturation.
Date: June 29, 1990
Creator: Kuzay, T. M.
System: The UNT Digital Library
Process for forming one or more substantially pure layers in substrate material using ion implantation (open access)

Process for forming one or more substantially pure layers in substrate material using ion implantation

The method comprises selecting an implantable element and a substrate material to be implanted which, at the implant/anneal temperatures, have limited mutual solubility and have no intermediate phases formed. In an example, Be is implanted with 11 {times}10{sup 17} Al/cm{sup 2} at 200 keV and then annealed for 1 h at 500 C. Rutherford backscattering shows that layer formation occurred during the anneal. SEM shows rectangular Be defects in the Al layer. Other examples of implantable elements and suitable substrate materials are tabulated. 6 figs, 1 table. (DLC)
Date: December 31, 1990
Creator: Musket, R. G.; Brown, D. W. & Munir, Z. A.
System: The UNT Digital Library
Supported liquid membrane system (open access)

Supported liquid membrane system

A cell apparatus for a supported liquid membrane including opposing faceplates, each having a spirally configured groove, an inlet groove at a first end of the spirally configured groove, and an outlet groove at the other end of the spirally configured groove, within the opposing faces of the faceplates, a microporous membrane situated between the grooved faces of the faceplates, said microporous membrane containing an extractant mixture selective for a predetermined chemical species within the pores of said membrane, means for aligning the grooves of the faceplates in an directly opposing configuration with the porous membrane being situated therebetween, such that the aligned grooves form a pair of directly opposing channels, separate feed solution and stripping solution compartments connected to respective channels between the faceplates and the membrane, separate pumping means for passing feed solution and stripping solution through the channels is provided.
Date: December 31, 1990
Creator: Takigawa, D. Y. & Bush, H. Jr.
System: The UNT Digital Library
Extrusion of metal oxide superconducting wire, tube or ribbon (open access)

Extrusion of metal oxide superconducting wire, tube or ribbon

A process and apparatus for extruding a superconducting metal oxide composition YBa{sub 2}Cu{sub 3}O{sub 7-x} provides a wire (tube or ribbon) having a cohesive mass and a degree of flexibility together with enhanced electrical properties. Wire diameters in the range of 6--85 mils have been produced with smaller wires on the order of 10 mils in diameter exhibiting enhanced flexibility for forming braided, or multistrand, configurations for greater current carrying capacity. The composition for extrusion contains a polymeric binder to provide a cohesive mass to bind the particles together during the extrusion process with the binder subsequently removed at lower temperatures during sintering. The composition for extrusion further includes a deflocculent, an organic plasticizer and a solvent which also are subsequently removed during sintering. Electrically conductive tubing with an inner diameter of 52 mil and an outer diameter of 87--335 mil has also been produced. Flat ribbons have been produced in the range of 10--125 mil thick by 100--500 mil wide. The superconducting wire, tube or ribbon may include an outer ceramic insulating sheath co-extruded with the wire, tubing or ribbon.
Date: December 31, 1990
Creator: Dusek, Joseph T.
System: The UNT Digital Library
High current pulse transmission cable (open access)

High current pulse transmission cable

This invention is comprised of a transmission cable for carrying high current pulses in which an even numbered plurality of electrical conductors surrounds a central ground conductor. Each electrical conductor is connected so that it at any instant in time it will carry current of opposite polarity to the polarity carried by adjacent conductors. This arrangement cancels practically all of the external fields generated by current in the conductors.
Date: September 28, 1990
Creator: Parsons, W. M.
System: The UNT Digital Library
Process for alloying uranium and niobium (open access)

Process for alloying uranium and niobium

Alloys such as U-6Nb are prepared by forming a stacked sandwich array of uranium sheets and niobium powder disposed in layers between the sheets, heating the array in a vacuum induction melting furnace to a temperature such as to melt the uranium, holding the resulting mixture at a temperature above the melting point of uranium until the niobium dissolves in the uranium, and casting the uranium-niobium solution. Compositional uniformity in the alloy product is enabled by use of the sandwich structure of uranium sheets and niobium powder.
Date: December 31, 1990
Creator: Holcombe, Cressie E.; Northcutt, Walter G.; Masters, David R. & Chapman, Lloyd R.
System: The UNT Digital Library
Electrical safety device (open access)

Electrical safety device

This invention consists of an electrical safety device for use in power tools that is designed to automatically discontinue operation of the power tool upon physical contact of the tool with a concealed conductive material. A step down transformer is used to supply the operating power for a disconnect relay and reset delay. When physical contact is made between the power tool and the conductive material, an electrical circuit through the disconnect relay is completed and the operation of the power tool is automatically interrupted. Once the contact between the tool and conductive material is broken, the power tool can be quickly and easily reactivated by a reset push button activating the reset relay. A remote reset is provided for convenience and efficiency of operation.
Date: September 6, 1990
Creator: White, D. B.
System: The UNT Digital Library
Calcination and solid state reaction of ceramic-forming components to provide single-phase ceramic product having fine particle size (open access)

Calcination and solid state reaction of ceramic-forming components to provide single-phase ceramic product having fine particle size

The invention consists of an improved method for the preparation of single phase, fine grained ceramic materials from precursor powder mixtures where at least one of the components of the mixture is an alkali earth carbonate. The process consists of heating the precursor powders in a partial vacuum under flowing oxygen and under conditions where the partial pressure of CO{sub 2} evolved during the calcination is kept to a very low level relative to the oxygen. The process has been found particularly suitable for the preparation of high temperature copper oxide superconducting materials such as YBa{sub 2}Cu{sub 3}O{sub x} ``123`` and YBa{sub 2}Cu{sub 4}O{sub 8} ``124``.
Date: September 28, 1990
Creator: Balachandran, U.; Poeppel, R. B.; Emerson, J. E. & Johnson, S. A.
System: The UNT Digital Library
Silicon nitride reinforced with molybdenum disilicide (open access)

Silicon nitride reinforced with molybdenum disilicide

Compositions of matter comprised of silicon nitride and molybdenum disilicide and methods of making the compositions, where the molybdenum disilicide is present in amounts ranging from about 5 to about 50 vol%.
Date: December 31, 1990
Creator: Petrovic, John J. & Honnell, Richard E.
System: The UNT Digital Library
Production of hollow aerogel microspheres (open access)

Production of hollow aerogel microspheres

A method is described for making hollow aerogel microspheres of 800--1200{mu} diameter and 100--300{mu} wall thickness by forming hollow alcogel microspheres during the sol/gel process in a catalytic atmosphere and capturing them on a foam surface containing catalyst. Supercritical drying of the formed hollow alcogel microspheres yields hollow aerogel microspheres which are suitable for ICF targets.
Date: December 31, 1990
Creator: Upadhye, Ravindra S. & Henning, Sten A.
System: The UNT Digital Library
Method of solubilizing phthalocyanines and metallophthalocyanines (open access)

Method of solubilizing phthalocyanines and metallophthalocyanines

A one-step method of manufacturing soluble phthalocyanines and metallophthalocyanines, like zinc phthalocyanine, by converting a phthalocyanine or a metallophthalocyanine to a trialkylsilyl-substituted derivative is disclosed. The phthalocyanine or metallophthalocyanine is converted to a soluble trialkylsilyl-substituted derivative by interacting the phthalocyanine or metallophthalocyanine with an active metal amide, like lithium 2,2,6, 6-tetra-methylpiperidide, and a halotrialkylsilane, like chlorotrimethylsilane, to provide a phthalocyanine compound, like phthalocyanine monomers, dimers or polymers, metalated or unmetalated, that are soluble in organic media.
Date: June 1, 1990
Creator: Rathke, Jerome W.; Chen, Michael J. & Fendrick, Carol M.
System: The UNT Digital Library
Process of making cryogenically cooled high thermal performance crystal optics (open access)

Process of making cryogenically cooled high thermal performance crystal optics

A method for constructing a cooled optic wherein one or more cavities are milled, drilled or formed using casting or ultrasound laser machining techniques in a single crystal base and filled with porous material having high thermal conductivity at cryogenic temperatures. A non-machined strain-free single crystal can be bonded to the base to produce superior optics. During operation of the cooled optic, N{sub 2} is pumped through the porous material at a sub-cooled cryogenic inlet temperature and with sufficient system pressure to prevent the fluid bulk temperature from reaching saturation.
Date: June 29, 1990
Creator: Kuzay, Tuncer M.
System: The UNT Digital Library
Toroidal magnetic detector for high resolution measurement of muon momenta (open access)

Toroidal magnetic detector for high resolution measurement of muon momenta

A muon detector system including central and end air-core superconducting toroids and muon detectors enclosing a central calorimeter/detector are described in this paper. Muon detectors are positioned outside of toroids and all muon trajectory measurements are made in a nonmagnetic environment. Internal support for each magnet structure is provided by sheets, located at frequent and regularly spaced azimuthal planes, which interconnect the structural walls of the toroidal magnets. In a preferred embodiment, the shape of the toroidal magnet volume is adjusted to provide constant resolution over a wide range of rapidity.
Date: November 30, 1990
Creator: Bonanos, P.
System: The UNT Digital Library
Flame quality monitor system for fixed firing rate oil burners (open access)

Flame quality monitor system for fixed firing rate oil burners

A method and apparatus for determining and indicating the flame quality, or efficiency of the air-fuel ratio, in a fixed firing rate heating unit, such as an oil burning furnace, is provided. When the flame brightness falls outside a preset range, the flame quality, or excess air, has changed to the point that the unit should be serviced. The flame quality indicator output is in the form of lights mounted on the front of the unit. A green light indicates that the flame is about in the same condition as when the burner was last serviced. A red light indicates a flame which is either too rich or too lean, and that servicing of the burner is required. At the end of each firing cycle, the flame quality indicator goes into a hold mode which is in effect during the period that the burner remains off. A yellow or amber light indicates that the burner is in the hold mode. In this mode, the flame quality lights indicate the flame condition immediately before the burner turned off. Thus the unit can be viewed when it is off, and the flame condition at the end of the previous firing cycle can …
Date: October 23, 1990
Creator: Butcher, T. A. & Cerniglia, P.
System: The UNT Digital Library
A unique system of Fe/Pd for magneto-optical recording and magnetic switching devices (open access)

A unique system of Fe/Pd for magneto-optical recording and magnetic switching devices

This invention is comprised of a high density magneto-optical information storage medium utilizing the properties of an ultrathin iron film on a palladium substrate. The present invention comprises a magneto-optical medium capable of thermal and magnetic stability and capable of possessing a vertical orientation of the magnetization vector for the magnetic material. Data storage relies on the temperature dependence of the coercivity of the ultrathin film. Data retrieval derives from the Kerr effect which describes the direction of rotation of a plane of polarized light traversing the ultrathin magnetic material as a function of the orientation of the magnetization vector.
Date: May 22, 1990
Creator: Liu, Chian Q. & Bader, S. D.
System: The UNT Digital Library
Processing method for superconducting ceramics (open access)

Processing method for superconducting ceramics

A process for preparing a superconducting ceramic and particularly YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}, where {delta} is in the order of about 0.1--0.4, is carried out using a polymeric binder which decomposes below its ignition point to reduce carbon residue between the grains of the sintered ceramic and a nonhydroxylic organic solvent to limit the problems with water or certain alcohols on the ceramic composition.
Date: May 7, 1990
Creator: Bloom, I. D.; Poeppel, R. B. & Flandermeyer, B. K.
System: The UNT Digital Library
Method for co-processing waste rubber and carbonaceous material (open access)

Method for co-processing waste rubber and carbonaceous material

In a process for the co-processing of waste rubber and carbonaceous material to form a useful liquid product, the rubber and the carbonaceous material are combined and heated to the depolymerization temperature of the rubber in the presence of a source of hydrogen. The deploymerized rubber acts as a liquefying solvent for the carbonaceous material while a beneficial catalytic effect is obtained from the carbon black released on deploymerization the reinforced rubber. The reaction is carried out at liquefaction conditions of 380--600{degrees}C and 70--280 atmospheres hydrogen pressure. The resulting liquid is separated from residual solids and further processed such as by distillation or solvent extraction to provide a carbonaceous liquid useful for fuels and other purposes.
Date: October 9, 1990
Creator: Farcasiu, M. & Smith, C. M.
System: The UNT Digital Library