Patents by Inventor Sang H. Choi

Sang H. Choi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20090140296
    Abstract: Hetero-epitaxial semiconductor materials comprising cubic crystalline semiconductor alloys grown on the basal plane of trigonal and hexagonal substrates, in which misfit dislocations are reduced by approximate lattice matching of the cubic crystal structure to underlying trigonal or hexagonal substrate structure, enabling the development of alloyed semiconductor layers of greater thickness, resulting in a new class of semiconductor materials and corresponding devices, including improved hetero-bipolar and high-electron mobility transistors, and high-mobility thermoelectric devices.
    Type: Application
    Filed: October 20, 2008
    Publication date: June 4, 2009
    Applicants: Space Administration
    Inventors: Yeonjoon Park, Sang H. Choi, Glen C. King
  • Publication number: 20090136828
    Abstract: Carbon nanotubes (CNTs) are mixed in an aqueous buffer solution that includes a buffer material having a molecular structure defined by a first end, a second end, and a middle disposed between the first and second ends. The first end is a cyclic ring with nitrogen and oxygen heteroatomes, the middle is a hydrophobic alkyl chain, and the second end is a charged group. The resulting solution includes the CNTs dispersed therein. Metal-core ferritins are then mixed into the resulting solution where at least a portion of the ferritins are coupled to the CNTs.
    Type: Application
    Filed: November 18, 2008
    Publication date: May 28, 2009
    Applicants: Space Administration
    Inventors: Jae-Woo Kim, Peter T. Lillehei, Cheol Park, Sang H. Choi
  • Publication number: 20090134362
    Abstract: Carbon nanotubes (CNTs) are dispersed in an aqueous buffer solution consisting of at least 50 weight percent water and a remainder weight percent that includes a buffer material. The buffer material has a molecular structure defined by a first end, a second end, and a middle disposed between the first and second ends. The first end is a cyclic ring with nitrogen and oxygen heteroatomes, the middle is a hydrophobic alkyl chain, and the second end is a charged group.
    Type: Application
    Filed: November 18, 2008
    Publication date: May 28, 2009
    Applicants: Space Administration
    Inventors: Jae-Woo Kim, Cheol Park, Sang H. Choi, Peter T. Lillehei, Joycelyn S. Harrison
  • Patent number: 7514726
    Abstract: A lattice matched silicon germanium (SiGe) semiconductive alloy is formed when a {111} crystal plane of a cubic diamond structure SiGe is grown on the {0001} C-plane of a single crystalline Al2O3 substrate such that a <110> orientation of the cubic diamond structure SiGe is aligned with a <1,0,?1,0> orientation of the {0001} C-plane. A lattice match between the substrate and the SiGe is achieved by using a SiGe composition that is 0.7223 atomic percent silicon and 0.2777 atomic percent germanium. A layer of Si1-xGex is formed on the cubic diamond structure SiGe. The value of X (i) defines an atomic percent of germanium satisfying 0.2277<X<1.0, (ii) is approximately 0.2777 where the layer of Si1-xGex interfaces with the cubic diamond structure SiGe, and (iii) increases linearly with the thickness of the layer of Si1-xGex.
    Type: Grant
    Filed: March 21, 2006
    Date of Patent: April 7, 2009
    Assignee: The United States of America as represented by the Aministrator of the National Aeronautics and Space Administration
    Inventors: Yeonjoon Park, Sang H. Choi, Glen C. King, James R. Elliott, Jr., Diane M. Stoakley
  • Patent number: 7510802
    Abstract: A thin-film electrode for a bio-nanobattery is produced by consecutively depositing arrays of a ferritin protein on a substrate, employing a spin self-assembly procedure. By this procedure, a first ferritin layer is first formed on the substrate, followed by building a second, oppositely-charged ferritin layer on the top of the first ferritin layer to form a bilayer structure. Oppositely-charged ferritin layers are subsequently deposited on top of each other until a desired number of bilayer structures is produced. An ordered, uniform, stable and robust, thin-film electrode material of enhanced packing density is presented, which provides optimal charge density for the bio-nanobattery.
    Type: Grant
    Filed: March 9, 2006
    Date of Patent: March 31, 2009
    Assignees: National Institute of Aerospace Associates, The United States of America as represented by the Administration of NASA
    Inventors: Sang-Hyon Chu, Sang H. Choi, Jae-Woo Kim, Peter T. Lillehei, Yeonjoon Park, Glen C. King, James R. Elliott, Jr.
  • Publication number: 20090072078
    Abstract: A new High Altitude Airship (HAA) capable of various extended applications and mission scenarios utilizing inventive onboard energy harvesting and power distribution systems. The power technology comprises an advanced thermoelectric (ATE) thermal energy conversion system. The high efficiency of multiple stages of ATE materials in a tandem mode, each suited for best performance within a particular temperature range, permits the ATE system to generate a high quantity of harvested energy for the extended mission scenarios. When the figure of merit 5 is considered, the cascaded efficiency of the three-stage ATE system approaches an efficiency greater than 60 percent.
    Type: Application
    Filed: July 31, 2007
    Publication date: March 19, 2009
    Applicants: Space Administration
    Inventors: Sang H. Choi, James R. Elliott, JR., Glen C. King, Yeonjoon Park, Jae-Woo Kim, Sang-Hyon Chu
  • Patent number: 7379231
    Abstract: A light control device is formed by ferroelectric material and N electrodes positioned adjacent thereto to define an N-sided regular polygonal region or circular region therebetween where N is a multiple of four.
    Type: Grant
    Filed: September 7, 2006
    Date of Patent: May 27, 2008
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Yeonjoon Park, Sang H. Choi, Glen C. King, Jae-Woo Kim, James R. Elliott, Jr.
  • Patent number: 7375808
    Abstract: An optical method and system sense and identify a foreign particle in a gaseous environment. A light source generates light. An electrically-conductive sheet has an array of holes formed through the sheet. Each hole has a diameter that is less than one quarter of the light's wavelength. The sheet is positioned relative to the light source such that the light is incident on one face of the sheet. An optical detector is positioned adjacent the sheet's opposing face and is spaced apart therefrom such that a gaseous environment is adapted to be disposed therebetween. Alterations in the light pattern detected by the optical detector indicate the presence of a foreign particle in the holes or on the sheet, while a laser induced fluorescence (LIF) signature associated with the foreign particle indicates the identity of the foreign particle.
    Type: Grant
    Filed: September 28, 2006
    Date of Patent: May 20, 2008
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Sang H. Choi, Yeonjoon Park
  • Publication number: 20080079938
    Abstract: An optical method and system sense and identify a foreign particle in a gaseous environment. A light source generates light. An electrically-conductive sheet has an array of holes formed through the sheet. Each hole has a diameter that is less than one quarter of the light's wavelength. The sheet is positioned relative to the light source such that the light is incident on one face of the sheet. An optical detector is positioned adjacent the sheet's opposing face and is spaced apart therefrom such that a gaseous environment is adapted to be disposed therebetween. Alterations in the light pattern detected by the optical detector indicate the presence of a foreign particle in the holes or on the sheet, while a laser induced fluorescence (LIF) signature associated with the foreign particle indicates the identity of the foreign particle.
    Type: Application
    Filed: September 28, 2006
    Publication date: April 3, 2008
    Applicants: Space Administration
    Inventors: Sang H. Choi, Yeonjoon Park
  • Publication number: 20080074723
    Abstract: A light control device is formed by ferroelectric material and N electrodes positioned adjacent thereto to define an N-sided regular polygonal region or circular region therebetween where N is a multiple of four.
    Type: Application
    Filed: September 7, 2006
    Publication date: March 27, 2008
    Applicant: U.S.A. as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Yeonjoon Park, Sang H. Choi, Glen C. King, Jae-Woo Kim, James R. Elliott
  • Patent number: 7341883
    Abstract: A silicon germanium (SiGe) semiconductive alloy is grown on a substrate of single crystalline Al2O3. A {111} crystal plane of a cubic diamond structure SiGe is grown on the substrate's {0001} C-plane such that a <110> orientation of the cubic diamond structure SiGe is aligned with a <1,0,?1,0> orientation of the {0001} C-plane. A lattice match between the substrate and the SiGe is achieved by using a SiGe composition that is 0.7223 atomic percent silicon and 0.2777 atomic percent germanium.
    Type: Grant
    Filed: September 27, 2005
    Date of Patent: March 11, 2008
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Yeonjoon Park, Sang H. Choi, Glen C. King
  • Publication number: 20080014621
    Abstract: Metal nanoshells are fabricated by admixing an aqueous solution of metal ions with an aqueous solution of apoferritin protein molecules, followed by admixing an aqueous solution containing an excess of an oxidizing agent for the metal ions. The apoferritin molecules serve as bio-templates for the formation of metal nanoshells, which form on and are bonded to the inside walls of the hollow cores of the individual apoferritin molecules. Control of the number of metal atoms which enter the hollow core of each individual apoferritin molecule provides a hollow metal nonparticle, or nanoshell, instead of a solid spherical metal nanoparticle.
    Type: Application
    Filed: July 12, 2007
    Publication date: January 17, 2008
    Applicant: National Institute of Aerospace Associates
    Inventors: Jae-Woo Kim, Sang H. Choi, Peter T. Lillehei, Sang-Hyon Chu, Yeonjoon Park, Glen C. King, James R. Elliott