Patents by Inventor Chung-Hee Chang

Chung-Hee Chang 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).

  • Patent number: 9190095
    Abstract: An apparatus and method are provided for improving perpendicular magnetic recording media. The present invention provides media, and a method of fabricating media in a cost-effective manner, with a reduced ruthenium (Ru) content interlayer structure, while meeting media performance requirements. A perpendicular magnetic recording medium is provided comprising a non-magnetic substrate having a surface, and a layer stack situated on the substrate surface. The layer stack comprises, in overlying sequence from the substrate surface a magnetically soft underlayer; an amorphous or crystalline, non-magnetic seed layer; an interlayer structure for crystallographically orienting a layer of a perpendicular magnetic recording material situated on the underlayer; and at least one crystallographically oriented, magnetically hard, perpendicular magnetic recording layer situated on the interlayer structure.
    Type: Grant
    Filed: January 20, 2014
    Date of Patent: November 17, 2015
    Assignee: Seagate Technology LLC
    Inventors: Shoutao Wang, Weilu Xu, Chung-hee Chang, Xiaoguang Ma, Mark Johnson, Abebe Hailu, Charles Chen
  • Publication number: 20140186658
    Abstract: An apparatus and method are provided for improving perpendicular magnetic recording media. The present invention provides media, and a method of fabricating media in a cost-effective manner, with a reduced ruthenium (Ru) content interlayer structure, while meeting media performance requirements. A perpendicular magnetic recording medium is provided comprising a non-magnetic substrate having a surface, and a layer stack situated on the substrate surface. The layer stack comprises, in overlying sequence from the substrate surface a magnetically soft underlayer; an amorphous or crystalline, non-magnetic seed layer; an interlayer structure for crystallographically orienting a layer of a perpendicular magnetic recording material situated on the underlayer; and at least one crystallographically oriented, magnetically hard, perpendicular magnetic recording layer situated on the interlayer structure.
    Type: Application
    Filed: January 20, 2014
    Publication date: July 3, 2014
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Shoutao Wang, Weilu Xu, Chung-hee Chang, Xiaoguang Ma, Mark Johnson, Abebe Hailu, Charles Chen
  • Publication number: 20130295625
    Abstract: The present invention relates to an apparatus for treating organic waste including: a first circulation line having a first circulation pump connected thereon so as to supply a portion of the organic waste being acid fermented in an acid fermenter to a methane fermenter; a second circulation line having a second circulation pump connected thereon so as to supply a portion of anaerobic digestive fluid methane fermented in the methane fermenter to the acid fermenter; and vortex generating means having a plurality of first, second and third nozzles disposed in the methane fermenter so as to allow the anaerobic digestive fluid in the methane fermenter to be agitated by vortices generated thereof.
    Type: Application
    Filed: November 30, 2011
    Publication date: November 7, 2013
    Applicant: Hyundai Engineering & Construction Co., Ltd.
    Inventors: Chung-Hee Chang, Young-O Kim, Duk-Woo Jun
  • Patent number: 8557408
    Abstract: A recording medium having a substrate, a first soft magnetic underlayer, a second soft magnetic underlayer and a perpendicular magnetic recording layer without a spacer layer between the first and second soft magnetic underlayers is disclosed.
    Type: Grant
    Filed: April 3, 2012
    Date of Patent: October 15, 2013
    Assignee: Seagate Technology LLC
    Inventors: Qixu Chen, Charles Brucker, Chung-Hee Chang, Tom Nolan, Samuel Dacke Harkness, IV
  • Patent number: 8338005
    Abstract: A media for perpendicular recording and a method of creating the media is provided. The media includes a hard recording layer and a soft underlayer (SUL). The SUL is composed of at least two anti-ferromagnetically coupled (AFC) sub-underlayers. The sub-underlayers respond to a magnetic field established during dynamic reversal with respective magnetic fields. The sub-underlayers are formed and disposed to differ in one or more magnetic moment, anisotropy, and thickness, so that their respective magnetic fields constructively interfere in one or more points in the hard recording layer, thereby reducing a total SUL magnetic field response to the dynamic reversal field approximately to zero at one or more points in the hard recording layer, which reduces side track erasure.
    Type: Grant
    Filed: January 13, 2009
    Date of Patent: December 25, 2012
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Qixu Chen, Chung-Hee Chang, Thomas Patrick Nolan
  • Publication number: 20120225324
    Abstract: A recording medium having a substrate, a first soft magnetic underlayer, a second soft magnetic underlayer and a perpendicular magnetic recording layer without a spacer layer between the first and second soft magnetic underlayers is disclosed.
    Type: Application
    Filed: April 3, 2012
    Publication date: September 6, 2012
    Applicant: Seagate Technology LLC
    Inventors: Qixu Chen, Charles Brucker, Chung-Hee Chang, Tom Nolan, Samuel Dacke Harkness, IV
  • Patent number: 8147996
    Abstract: A recording medium having a substrate, a first soft magnetic underlayer, a second soft magnetic underlayer and a perpendicular magnetic recording layer without a spacer layer between the first and second soft magnetic underlayers is disclosed.
    Type: Grant
    Filed: June 7, 2005
    Date of Patent: April 3, 2012
    Assignee: Seagate Technology LLC
    Inventors: Qixu Chen, Charles Frederick Brucker, Chung-Hee Chang, Thomas Patrick Nolan, Samuel Dacke Harkness, IV
  • Patent number: 8025993
    Abstract: A perpendicular magnetic recording medium comprises a layer stack formed over a surface of a non-magnetic substrate, and comprising, in overlying sequence from the surface: a magnetically soft underlayer; an interlayer structure for crystallographically orienting a layer of a perpendicular magnetic recording material formed thereon; and at least one crystallographically oriented, magnetically hard, perpendicular magnetic recording layer on the interlayer structure; wherein the interlayer structure is a triple-layer stacked structure comprising: a first interlayer of a first non-magnetic material proximal the magnetically soft underlayer and containing Ru; a second interlayer of a second non-magnetic material in overlying contact with the first interlayer and not containing Ru; and a third interlayer of a third non-magnetic material in overlying contact with the second interlayer and containing Ru.
    Type: Grant
    Filed: February 23, 2007
    Date of Patent: September 27, 2011
    Assignee: Seagate Technology LLC
    Inventors: Abebe Hailu, Weilu Xu, Xiaoguang Ma, Chung-Hee Chang, Shoutao Wang, Charles C. Chen
  • Publication number: 20100177439
    Abstract: A media for perpendicular recording and a method of creating the media is provided. The media includes a hard recording layer and a soft underlayer (SUL). The SUL is composed of at least two anti-ferromagnetically coupled (AFC) sub-underlayers. The sub-underlayers respond to a magnetic field established during dynamic reversal with respective magnetic fields. The sub-underlayers are formed and disposed to differ in one or more magnetic moment, anisotropy, and thickness, so that their respective magnetic fields constructively interfere in one or more points in the hard recording layer, thereby reducing a total SUL magnetic field response to the dynamic reversal field approximately to zero at one or more points in the hard recording layer, which reduces side track erasure.
    Type: Application
    Filed: January 13, 2009
    Publication date: July 15, 2010
    Applicant: Seagate Technology LLC
    Inventors: Kaizhong Gao, Qixu Chen, Chung-Hee Chang, Thomas Patrick Nolan
  • Publication number: 20080204933
    Abstract: A perpendicular magnetic recording medium comprises a layer stack formed over a surface of a non-magnetic substrate, and comprising, in overlying sequence from the surface: a magnetically soft underlayer; an interlayer structure for crystallographically orienting a layer of a perpendicular magnetic recording material formed thereon; and at least one crystallographically oriented, magnetically hard, perpendicular magnetic recording layer on the interlayer structure; wherein the interlayer structure is a triple-layer stacked structure comprising: a first interlayer of a first non-magnetic material proximal the magnetically soft underlayer and containing Ru; a second interlayer of a second non-magnetic material in overlying contact with the first interlayer and not containing Ru; and a third interlayer of a third non-magnetic material in overlying contact with the second interlayer and containing Ru.
    Type: Application
    Filed: February 23, 2007
    Publication date: August 28, 2008
    Inventors: Abebe Hailu, Weilu Xu, Xiaoguang Ma, Chung-Hee Chang, Shoutao Wang, Charles C. Chen
  • Patent number: 7354618
    Abstract: A method of manufacturing magnetic recording media, comprising sequential steps of: (a) providing an apparatus for manufacturing the media; (b) supplying the apparatus with at least one substrate for the media; (c) forming a magnetic recording layer on the at least one substrate in a first portion of the apparatus, the magnetic recording layer including a surface; (d) treating the surface of the magnetic recording layer with an ionized oxygen-containing plasma in a second portion of the apparatus to form a plasma oxidized surface layer; and (e) forming a protective overcoat layer on the plasma oxidized surface layer of the magnetic recording layer in a third portion of the apparatus.
    Type: Grant
    Filed: November 12, 2003
    Date of Patent: April 8, 2008
    Assignee: Seagate Technology LLC
    Inventors: Chung-Hee Chang, Xiaoding Ma, Michael Joseph Stirniman, Jeffrey Shane Reiter, Samuel Dacke Harkness, IV, Rajiv Ranjan
  • Patent number: 7235314
    Abstract: A magnetic recording medium, the order of layers in which is the substrate, the soft underlayer, the seedlayer, the 1st RuCrx-containing interlayer, the 2nd RuCrx-containing interlayer and the magnetic recording layer with preferably a oxides or nitrides-containing magnetic layer comprising grains, is disclosed. High-chromium ruthenium-chromium alloy used as inter layers significantly enhances coercivity and SMNR preferably due to the improved lattice match between RuCr inter layers and CoPt-based magnetic recording layers, and the surface energy of RuCr layers contributes to the performance improvement with the high-chromium addition into Ru inter layers.
    Type: Grant
    Filed: March 11, 2004
    Date of Patent: June 26, 2007
    Assignee: Seagate Technology LLC
    Inventors: Qixu Chen, Chung-Hee Chang, Li-Lien Lee, Samuel D. Harkness, IV
  • Patent number: 7192663
    Abstract: A perpendicular magnetic recording medium having a substrate, a seedlayer on the substrate and a magnetic underlayer on the seedlayer, the magnetic underlayer having an easy axis of magnetization substantially directed in a radial or transverse direction, and a process for manufacturing the perpendicular magnetic recording medium are disclosed.
    Type: Grant
    Filed: December 8, 2003
    Date of Patent: March 20, 2007
    Assignee: Seagate Technology LLC
    Inventors: Chung-Hee Chang, Rajiv Y. Ranjan
  • Patent number: 7175766
    Abstract: Provided is an apparatus and method for performing tertiary treatment of sewage based on porous filtering media. The apparatus for performing tertiary treatment of sewage based on porous filtering media includes a reaction tank for receiving effluent wastewater from a primary settling tank; and porous filtering media, which is located in the reaction tank and has a predetermined size of surface area and opening, for settling suspension in the effluent wastewater and removing organic matter and nutritive salts included in the suspension.
    Type: Grant
    Filed: December 2, 2002
    Date of Patent: February 13, 2007
    Assignee: Korea Institute of Construction Technology
    Inventors: Young-Sug Kim, Moon-Hyoung Lee, Hong-Kyu Jang, Chung-Hee Chang, Chai-Sung Gee
  • Publication number: 20060275628
    Abstract: A recording medium having a substrate, a first soft magnetic underlayer, a second soft magnetic underlayer and a perpendicular magnetic recording layer without a spacer layer between the first and second soft magnetic underlayers is disclosed.
    Type: Application
    Filed: June 7, 2005
    Publication date: December 7, 2006
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Qixu Chen, Charles Brucker, Chung-Hee Chang, Tom Nolan, Samuel Harkness
  • Publication number: 20060231489
    Abstract: Provided is an apparatus and method for performing tertiary treatment of sewage based on porous filtering media. The apparatus for performing tertiary treatment of sewage based on porous filtering media includes a reaction tank for receiving effluent wastewater from a primary settling tank; and porous filtering media, which is located in the reaction tank and has a predetermined size of surface area and opening, for settling suspension in the effluent wastewater and removing organic matter and nutritive salts included in the suspension.
    Type: Application
    Filed: December 2, 2002
    Publication date: October 19, 2006
    Inventors: Young-Sug Kim, Moon-Hyoung Lee, Hong-Kyu Jang, Chung-Hee Chang, Chai-Sung Gee
  • Patent number: 7081268
    Abstract: A method of manufacturing a magnetic recording medium comprises sequential steps of: (a) providing an apparatus for manufacturing the medium; (b) supplying the apparatus with a substrate for the medium; (c) forming a magnetic recording layer on the substrate in a first portion of the apparatus; (d) treating the magnetic recording layer with oxygen gas in a second portion of the apparatus at a sub-atmospheric pressure and for an interval sufficient to provide the resultant medium with at least one of the following, relative to a similar medium manufactured by a similar method but wherein the oxygen treatment of step (d) is not performed: (i) a more negative nucleation field (Hn); (ii) increased remanent squareness (Sr); (iii) increased signal-to-medium noise ratio (SMNR); (iv) narrower switching field distribution (SFD); and (v) decreased thermal decay rate; and (e) forming a protective overcoat layer on the oxygen-treated magnetic recording layer in a third portion of the apparatus.
    Type: Grant
    Filed: September 17, 2003
    Date of Patent: July 25, 2006
    Assignee: Seagate Technology LLC
    Inventors: Chung-Hee Chang, Charles F. Brucker
  • Patent number: 7060376
    Abstract: A perpendicular magnetic recording medium having a substrate, an amorphous soft underlayer and a magnetic layer for perpendicular recording has reduced DC noise and surface roughness, which reduces the head-to-media spacing and the head-to-amorphous soft underlayer spacing.
    Type: Grant
    Filed: May 10, 2002
    Date of Patent: June 13, 2006
    Assignee: Seagate Technology LLC
    Inventors: Chung-Hee Chang, Rajiv Y. Ranjan
  • Publication number: 20050202286
    Abstract: A magnetic recording medium, the order of layers in which is the substrate, the soft underlayer, the seedlayer, the 1st RuCrx-containing interlayer, the 2nd RuCrx-containing interlayer and the magnetic recording layer with preferably a oxides or nitrides-containing magnetic layer comprising grains, is disclosed. High-chromium ruthenium-chromium alloy used as inter layers significantly enhances coercivity and SMNR preferably due to the improved lattice match between RuCr inter layers and CoPt-based magnetic recording layers, and the surface energy of RuCr layers contributes to the performance improvement with the high-chromium addition into Ru inter layers.
    Type: Application
    Filed: March 11, 2004
    Publication date: September 15, 2005
    Applicant: SEAGATE TECHNOLOGY LLC.
    Inventors: Qixu Chen, Chung-Hee Chang, Li-Lien Lee, Samuel Harkness
  • Publication number: 20050163037
    Abstract: A perpendicular magnetic recording medium having a substrate and a magnetic underlayer on the substrate, the magnetic underlayer having an easy axis of magnetization substantially directed in a radial or transverse direction, and a process for manufacturing the perpendicular magnetic recording medium are disclosed.
    Type: Application
    Filed: March 22, 2005
    Publication date: July 28, 2005
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Chung-Hee Chang, Rajiv Ranjan