Patents Represented by Attorney Philip Summa
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Patent number: 7682709Abstract: A method of preparing an n-type epitaxial layer of aluminum nitride conductively doped with germanium comprises directing a molecular beam of aluminum atoms onto the growth surface of a substrate that provides an acceptable lattice match for aluminum nitride; directing a molecular beam of activated nitrogen to the growth surface of the substrate; and directing a molecular beam of germanium to the growth surface of the substrate; while maintaining the growth surface of the substrate at a temperature high enough to provide the surface mobility and sticking coefficient required for epitaxial growth, but lower than the temperature at which the surface would decompose or the epitaxial layer disassociate back into atomic or molecular species.Type: GrantFiled: October 30, 1995Date of Patent: March 23, 2010Assignee: North Carolina State UniversityInventors: Robert F. Davis, Cheng Wang
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Patent number: 6031065Abstract: A method is disclosed of producing a copolymer of polyethylene terephthalate and polyethylene naphthalate. The method comprises esterifying a combination of a diester of naphthalene, terephthalic acid, and ethylene glycol to produce an esterification reaction mixture that includes the alcohol byproduct of the naphthalene diester, distilling the reaction mixture to remove at least a portion of the esterification byproducts from the reaction mixture in the form of a vapor stream of which the majority component is water vapor and which includes the alcohol byproduct of the naphthalate ester in the vapor state, and combusting at least a portion of the vapor stream under conditions sufficient to decompose at least a portion of the alcohol byproduct present in the vapor stream.Type: GrantFiled: February 2, 1998Date of Patent: February 29, 2000Assignee: Wellman, Inc.Inventors: Carl S. Nichols, Robert Adrian Ellis, James Scott Thomas
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Patent number: 5985773Abstract: A fabric for tents consisting a gray woven from nylon or polyester filaments and a layer of coating composition including polyurethane, a pigment, an ultraviolet inhibitor, aluminum powders, ceramic powders, a fire retardant agent and a solvent can be protected from a yellowing appearance caused by ultraviolet rays and has a preferable color. The lifetime of the fabric can be extended. And the comparative low cost and short time are necessary for the process for preparing the fabric.Type: GrantFiled: January 6, 1998Date of Patent: November 16, 1999Inventor: Youn Jae Lee
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Patent number: 5972801Abstract: A method is disclosed for obtaining improved oxide layers and resulting improved performance from oxide based devices. The method comprises exposing an oxide layer on a silicon carbide layer to an oxidizing source gas at a temperature below the temperature at which SiC would begin to oxidize at a significant rate, while high enough to enable the oxidizing source gas to diffuse into the oxide layer, and while avoiding any substantial additional oxidation of the silicon carbide, and for a time sufficient to densify the oxide layer and improve the interface between the oxide layer and the silicon carbide layer.Type: GrantFiled: November 8, 1995Date of Patent: October 26, 1999Assignee: Cree Research, Inc.Inventors: Lori A. Lipkin, David B. Slater, Jr., John W. Palmour
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Patent number: 5972711Abstract: A method for microwave assisted chemical processes is disclosed that comprises applying sufficient microwave radiation to a temperature-monitored mixture of reagents, with at least one of the reagents being thermally responsive to electromagnetic radiation in the microwave range, and based on the monitored temperature, to maintain the added reagents at or closely about a predetermined temperature while substantially avoiding thermal dilution (or before substantial thermal dilution can occur) that otherwise would have been caused by the addition of the reagents to one another.Type: GrantFiled: July 22, 1998Date of Patent: October 26, 1999Assignee: CEM CorporationInventors: David A. Barclay, William Edward Jennings, Edward E. King
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Patent number: 5970700Abstract: A drafting and spinning apparatus is disclosed that produces highly uniform yarns with improved mechanical properties. The apparatus comprises a plurality of pairs of drafting rolls for drawing a sliver formed of one or more types of staple fibers, each fiber type having a predetermined effective fiber length. The plurality of pairs of drafting rolls comprises at least two pairs of intermediate rolls, with the distances between the nips of adjacent intermediate roll pairs being no more than the effective fiber length of the longest fiber type in the sliver. The apparatus further includes device for spinning the sliver into yarn at a take-up speed of greater than 150 meters/minute.Type: GrantFiled: December 23, 1997Date of Patent: October 26, 1999Assignee: Wellman, Inc.Inventors: Todd Joseph Scheerer, Winston Patrick Moore, Jesse Robert Fletcher, Rudy Lee Crews
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Patent number: 5960621Abstract: A spinning apparatus is disclosed according to the invention having a drafting zone comprising at least four roll pairs for drawing a sliver comprising one or more types of staple fibers. The rolls pairs include a back roll pair, intermediate roil pairs and a front roll pair and the distance between the nip of the back roll pair and the nip of the adjacent intermediate roll pair, and the distances between the nips of adjacent intermediate roll pairs is no more than the effective fiber length of the longest staple fiber type in the sliver. The drafted sliver may be spun into yarns at high speeds, such as the speeds used in air jet spinning apparatus to provide yarns having increased strength and reduced defects. The present invention also includes a method of forming high quality and high uniformity yarns by advancing a sliver through a drafting apparatus and thereafter spinning the sliver into yarn.Type: GrantFiled: May 22, 1998Date of Patent: October 5, 1999Assignee: Wellman, Inc.Inventors: Todd Joseph Scheerer, Winston Patrick Moore, Jesse Robert Fletcher, Rudy Lee Crews
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Patent number: 5898058Abstract: A continuous process for producing polyethylene terephthalate polyester from terephthalic acid and ethylene glycol uses a stabilizer, preferably containing phosphorous, to produce a high quality polyethylene terephthalate polyester which is relatively free of the acetaldehyde and discoloration which are associated with the post-polymerization activity of a polymerization catalyst. The stabilizer is preferably added at or after the end of the polymerization reaction prior to polymer processing to deactivate the polymerization catalyst and can increase the throughput of the polyester without adversely affecting the thermal stability of the polyethylene terephthalate polyester. Alternatively, the late addition of the stabilizer can increase the thermal stability of the polyester without adversely affecting the throughput of the polyethylene terephthalate polyester.Type: GrantFiled: May 20, 1996Date of Patent: April 27, 1999Assignee: Wellman, Inc.Inventors: Carl S. Nichols, Tony Clifford Moore, Walter Lee Edwards
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Patent number: 5876644Abstract: A method of recycling post-consumer polyester to obtain recycled polyester of sufficiently high purity to meet food packaging requirements is disclosed. The method includes cleaning comminuted pieces of post-consumer polyester to remove surface contaminants; melting the surface-cleaned post-consumer polyester pieces; extruding the post-consumer melt; blending the melt of post-consumer polyester with a melt of virgin polyester prepolymer; solidifying and pelletizing the blended melt while the virgin polyester prepolymer remains as prepolymer; and polymerizing the solid blended pellets in the solid state.Type: GrantFiled: August 27, 1996Date of Patent: March 2, 1999Assignee: Wellman, Inc.Inventors: Carl S. Nichols, Tony Clifford Moore
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Patent number: 5838706Abstract: A Group III nitride laser structure is disclosed with an active layer that includes at least one layer of a Group III nitride or an alloy of silicon carbide with a Group III nitride, a silicon carbide substrate, and a buffer layer between the active layer and the silicon carbide substrate. The buffer layer is selected from the group consisting of gallium nitride, aluminum nitride, indium nitride, ternary Group III nitrides having the formula A.sub.x B.sub.1-x N, where A and B are Group III elements and where x is zero, one, or a fraction between zero and one, and alloys of silicon carbide with such ternary Group III nitrides. In preferred embodiments, the laser structure includes a strain-minimizing contact layer above the active layer that has a lattice constant substantially the same as the buffer layer.Type: GrantFiled: November 19, 1996Date of Patent: November 17, 1998Assignee: Cree Research, Inc.Inventors: John Adam Edmond, Gary E. Bulman, Hua-Shuang Kong