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).
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Patent number: 9190095Abstract: 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: GrantFiled: January 20, 2014Date of Patent: November 17, 2015Assignee: Seagate Technology LLCInventors: Shoutao Wang, Weilu Xu, Chung-hee Chang, Xiaoguang Ma, Mark Johnson, Abebe Hailu, Charles Chen
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Publication number: 20140186658Abstract: 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: ApplicationFiled: January 20, 2014Publication date: July 3, 2014Applicant: SEAGATE TECHNOLOGY LLCInventors: Shoutao Wang, Weilu Xu, Chung-hee Chang, Xiaoguang Ma, Mark Johnson, Abebe Hailu, Charles Chen
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Publication number: 20130295625Abstract: 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: ApplicationFiled: November 30, 2011Publication date: November 7, 2013Applicant: Hyundai Engineering & Construction Co., Ltd.Inventors: Chung-Hee Chang, Young-O Kim, Duk-Woo Jun
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Patent number: 8557408Abstract: 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: GrantFiled: April 3, 2012Date of Patent: October 15, 2013Assignee: Seagate Technology LLCInventors: Qixu Chen, Charles Brucker, Chung-Hee Chang, Tom Nolan, Samuel Dacke Harkness, IV
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Patent number: 8338005Abstract: 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: GrantFiled: January 13, 2009Date of Patent: December 25, 2012Assignee: Seagate Technology LLCInventors: Kaizhong Gao, Qixu Chen, Chung-Hee Chang, Thomas Patrick Nolan
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Publication number: 20120225324Abstract: 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: ApplicationFiled: April 3, 2012Publication date: September 6, 2012Applicant: Seagate Technology LLCInventors: Qixu Chen, Charles Brucker, Chung-Hee Chang, Tom Nolan, Samuel Dacke Harkness, IV
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Patent number: 8147996Abstract: 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: GrantFiled: June 7, 2005Date of Patent: April 3, 2012Assignee: Seagate Technology LLCInventors: Qixu Chen, Charles Frederick Brucker, Chung-Hee Chang, Thomas Patrick Nolan, Samuel Dacke Harkness, IV
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Patent number: 8025993Abstract: 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: GrantFiled: February 23, 2007Date of Patent: September 27, 2011Assignee: Seagate Technology LLCInventors: Abebe Hailu, Weilu Xu, Xiaoguang Ma, Chung-Hee Chang, Shoutao Wang, Charles C. Chen
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Publication number: 20100177439Abstract: 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: ApplicationFiled: January 13, 2009Publication date: July 15, 2010Applicant: Seagate Technology LLCInventors: Kaizhong Gao, Qixu Chen, Chung-Hee Chang, Thomas Patrick Nolan
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Publication number: 20080204933Abstract: 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: ApplicationFiled: February 23, 2007Publication date: August 28, 2008Inventors: Abebe Hailu, Weilu Xu, Xiaoguang Ma, Chung-Hee Chang, Shoutao Wang, Charles C. Chen
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Patent number: 7354618Abstract: 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: GrantFiled: November 12, 2003Date of Patent: April 8, 2008Assignee: Seagate Technology LLCInventors: Chung-Hee Chang, Xiaoding Ma, Michael Joseph Stirniman, Jeffrey Shane Reiter, Samuel Dacke Harkness, IV, Rajiv Ranjan
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Patent number: 7235314Abstract: 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: GrantFiled: March 11, 2004Date of Patent: June 26, 2007Assignee: Seagate Technology LLCInventors: Qixu Chen, Chung-Hee Chang, Li-Lien Lee, Samuel D. Harkness, IV
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Patent number: 7192663Abstract: 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: GrantFiled: December 8, 2003Date of Patent: March 20, 2007Assignee: Seagate Technology LLCInventors: Chung-Hee Chang, Rajiv Y. Ranjan
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Patent number: 7175766Abstract: 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: GrantFiled: December 2, 2002Date of Patent: February 13, 2007Assignee: Korea Institute of Construction TechnologyInventors: Young-Sug Kim, Moon-Hyoung Lee, Hong-Kyu Jang, Chung-Hee Chang, Chai-Sung Gee
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Publication number: 20060275628Abstract: 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: ApplicationFiled: June 7, 2005Publication date: December 7, 2006Applicant: SEAGATE TECHNOLOGY LLCInventors: Qixu Chen, Charles Brucker, Chung-Hee Chang, Tom Nolan, Samuel Harkness
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Publication number: 20060231489Abstract: 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: ApplicationFiled: December 2, 2002Publication date: October 19, 2006Inventors: Young-Sug Kim, Moon-Hyoung Lee, Hong-Kyu Jang, Chung-Hee Chang, Chai-Sung Gee
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Patent number: 7081268Abstract: 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: GrantFiled: September 17, 2003Date of Patent: July 25, 2006Assignee: Seagate Technology LLCInventors: Chung-Hee Chang, Charles F. Brucker
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Patent number: 7060376Abstract: 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: GrantFiled: May 10, 2002Date of Patent: June 13, 2006Assignee: Seagate Technology LLCInventors: Chung-Hee Chang, Rajiv Y. Ranjan
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Publication number: 20050202286Abstract: 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: ApplicationFiled: March 11, 2004Publication date: September 15, 2005Applicant: SEAGATE TECHNOLOGY LLC.Inventors: Qixu Chen, Chung-Hee Chang, Li-Lien Lee, Samuel Harkness
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Publication number: 20050163037Abstract: 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: ApplicationFiled: March 22, 2005Publication date: July 28, 2005Applicant: SEAGATE TECHNOLOGY LLCInventors: Chung-Hee Chang, Rajiv Ranjan