Patents by Inventor Naohito Yamada

Naohito Yamada 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: 7531554
    Abstract: Provision of a compound having an anti-HIV activity, particularly an integrase inhibitory activity. A 4-oxoquinoline compound represented by the following formula [I] or a pharmaceutically acceptable salt thereof: wherein each symbol is as defined in the specification.
    Type: Grant
    Filed: May 20, 2005
    Date of Patent: May 12, 2009
    Assignee: Japan Tobacco Inc.
    Inventors: Motohide Satoh, Takashi Matsuda, Satoshi Okuda, Hiroshi Kawakami, Hisateru Aramaki, Hisashi Shinkai, Yuji Matsuzaki, Wataru Watanabe, Kazunobu Yamataka, Shinichi Kiyonari, Shuichi Wamaki, Mitsuru Takahashi, Naohito Yamada, Akemi Nagao
  • Publication number: 20080220963
    Abstract: A method for producing sintered silicon nitride, including preparing a slurry from a base powder containing a silicon nitride powder and a sintering aid, the base powder having a particle size (D50) of 0.3 to 1 ?m; obtaining an SD powder from the slurry by a spray dryer process; and feeding the SD powder into a forming die and firing the powder under a compaction pressure of 3 ton/cm2 or more thereby obtaining sintered silicon nitride. The present invention provides a method for producing sintered silicon nitride with a higher degree of safety of the working environment.
    Type: Application
    Filed: February 27, 2008
    Publication date: September 11, 2008
    Applicant: NGK Insulators, Ltd.
    Inventors: Takahiro Takahashi, Kazuhiro Nobori, Naohito Yamada, Hideyuki Baba
  • Patent number: 7422992
    Abstract: An aluminum nitride sintered body is provided, which essentially contains aluminum nitride, 0.4 to 2.5 wt % magnesium and 2.0 to 5.0 wt % yttrium. The aluminum nitride sintered body has an average particle size of not more than 1.0 ?m.
    Type: Grant
    Filed: March 17, 2006
    Date of Patent: September 9, 2008
    Assignee: NGK Insulators, Ltd.
    Inventors: Naomi Teratani, Naohito Yamada
  • Patent number: 7332027
    Abstract: A method for manufacturing an aluminum nitride single crystal is provided, including the steps of preparing a raw material composition containing aluminum oxide and/or an aluminum oxide precursor which is converted into aluminum oxide by heating, and aluminum nitride and/or an aluminum nitride precursor which is converted into aluminum nitride by heating, heating the raw material composition at 1600 to 2400° C. to synthesize aluminum nitride, and causing crystal growth of the aluminum nitride to obtain an aluminum nitride single crystal.
    Type: Grant
    Filed: June 30, 2005
    Date of Patent: February 19, 2008
    Assignee: NGK Insulators, Ltd.
    Inventors: Yoshimasa Kobayashi, Toru Hayase, Naohito Yamada
  • Publication number: 20080012038
    Abstract: Carbon or a substance generating a carbon by thermal decomposition is added to prepared material containing aluminum nitride (AlN), an Si source such as silicon nitride (Si3N4) or a silicon oxide (SiO2), and an Eu source such as europium oxide (Eu2O3) or europium nitrate or europium acetate, and the prepared material is reduced in a nitrogen atmosphere, and subsequently fired. SiO2 is capable of converting into silicon nitride by reduction nitriding. Europium nitrate or europium acetate are capable of converting into Eu2O3 during a heat treatment process or converting into europium nitride (EuN) by reduction nitriding.
    Type: Application
    Filed: July 10, 2007
    Publication date: January 17, 2008
    Applicant: NGK Insulators, Ltd.
    Inventors: Naomi Teratani, Naohito Yamada
  • Patent number: 7288496
    Abstract: An aluminum nitride sintered body is provided, including a polycrystalline structure in which grain boundary fracture toughness KICgb is 1.6 MPa·m1/2 or more. The grain boundary fracture toughness KICgb is determined by the equation KICgb=KIC·cos2(?·PIF/200), wherein KIC is fracture toughness (MPa·m1/2), and PIF is a percentage of the intergranular fracture (%).
    Type: Grant
    Filed: June 18, 2004
    Date of Patent: October 30, 2007
    Assignee: NGK Insulators, Ltd.
    Inventors: Yoshimasa Kobayashi, Toru Hayase, Naohito Yamada
  • Publication number: 20070225152
    Abstract: The present inventors have found that an aluminum nitride sintered body excellent in flatness by polishing can be provided by improving the strength of a grain boundary; at the same time, by adding SiO2 or MgO, which forms a solid solution with aluminum nitride during a sintering process, with the result that it is no longer present as a grain boundary phase, in a small amount to an aluminum nitride powder, followed by sintering the aluminum nitride powder at a low temperature from more than 160° C. to less than 1750° C.
    Type: Application
    Filed: March 14, 2007
    Publication date: September 27, 2007
    Applicant: NGK Insulators, Ltd.
    Inventors: Yoshimasa Kobayashi, Naohito Yamada
  • Publication number: 20070215840
    Abstract: A conductive channel formed of an (Sm, Ce)Al11O18 is interconnected in the grain boundaries of aluminum nitride (AlN) particles, thereby reducing temperature dependency of volume resistivity of AlN sintered body; at the same time, the solid solution of the AlN particles is formed with at least one of C and Mg, to prevent the conductive channel from moving in AlN particles, thereby maintaining the volume resistivity within AlN particles at a high value even at a high temperature.
    Type: Application
    Filed: March 14, 2007
    Publication date: September 20, 2007
    Applicant: NGK Insulators, Ltd.
    Inventors: Jun Yoshikawa, Yoshimasa Kobayashi, Naohito Yamada
  • Patent number: 7250215
    Abstract: An aluminum nitride sintered body containing carbon fibers is provided. This aluminum nitride sintered body is obtained by mixing carbon fibers and aluminum nitride together to form mixed powder, molding the mixed powder to form a compact, and heating and sintering the compact in any of a vacuum atmosphere, an inert atmosphere and a reductive atmosphere. By using electric conductivity and shapes with high aspect ratios of the carbon fibers, continuous electrically conductive paths are formed with a small content of the carbon fibers. In this way, a value of resistance of the aluminum nitride sintered body is reduced.
    Type: Grant
    Filed: June 24, 2004
    Date of Patent: July 31, 2007
    Assignee: NGK Insulators, Ltd.
    Inventors: Jun Yoshikawa, Naohito Yamada, Hiroya Sugimoto
  • Publication number: 20070169689
    Abstract: A seed crystal is formed of a rod-like aluminum nitride single crystal whose length direction is oriented to the c-axis direction. Exposed surface on the side portion thereof on which an aluminum nitride material is grown into a crystal has an inclination of 90° relative to a {0001} surface. With this configuration, an aluminum nitride single crystal with excellent crystallinity can be manufactured.
    Type: Application
    Filed: January 3, 2007
    Publication date: July 26, 2007
    Applicant: NGK Insulators, Ltd.
    Inventors: Yoshimasa Kobayashi, Naohito Yamada
  • Publication number: 20070135293
    Abstract: An aluminum nitride ceramic including aluminum nitride grains and grain boundary phases comprises a grain boundary phase-rich layer including more amount of the grain boundary phases in a surface layer of the aluminum nitride ceramic than in an inside of the aluminum nitride ceramic. The grain boundary phases in the grain boundary phase-rich layer include at least one of rare earth element and alkali earth element.
    Type: Application
    Filed: February 21, 2007
    Publication date: June 14, 2007
    Applicant: NGK Insulators, Ltd.
    Inventors: Yoshimasa KOBAYASHI, Naohito YAMADA, Toru HAYASE
  • Patent number: 7229940
    Abstract: A dense cordierite based sintered body is provided, containing at least 93% by mass of cordierite among crystal components present in the sintered body. The average particle diameter of the particles constituting the sintered body is 2 ?m or less.
    Type: Grant
    Filed: March 23, 2005
    Date of Patent: June 12, 2007
    Assignee: NGK Insulators, Ltd.
    Inventors: Naomi Teratani, Naohito Yamada, Hiroaki Sakai
  • Patent number: 7211216
    Abstract: An aluminum nitride ceramic including aluminum nitride grains and grain boundary phases comprises a grain boundary phase-rich layer including more amount of the grain boundary phases in a surface layer of the aluminum nitride ceramic than in an inside of the aluminum nitride ceramic. The grain boundary phases in the grain boundary phase-rich layer include at least one of rare earth element and alkali earth element.
    Type: Grant
    Filed: June 15, 2005
    Date of Patent: May 1, 2007
    Assignee: NGK Insulators, Ltd.
    Inventors: Yoshimasa Kobayashi, Naohito Yamada, Toru Hayase
  • Patent number: 7122490
    Abstract: A novel aluminum nitride material having a low room temperature volume resistivity is provided. The aluminum nitride material has an aluminum nitride main component and includes at least 0.03 mol % of europium oxide. The aluminum nitride material has an aluminum nitride phase and an europium-aluminum composite oxide phase. An aluminum nitride material also provided having an aluminum nitride main component, wherein a total content of europium oxide and samarium oxide is at least 0.09 mol %. The aluminum nitride material has an aluminum nitride phase and a composite oxide phase containing at least europium and aluminum.
    Type: Grant
    Filed: February 24, 2004
    Date of Patent: October 17, 2006
    Assignee: NGK Insulators, Ltd.
    Inventors: Yoshimasa Kobayashi, Toru Hayase, Naomi Teratani, Jun Yoshikawa, Naohito Yamada
  • Publication number: 20060216533
    Abstract: A ceramic member comprises a ceramic sintered body and a metallic member, which includes a metal element and is formed to be in contact with the ceramic sintered body. An affected layer around the metallic member of the ceramic sintered body has a thickness of 300 ?m or less.
    Type: Application
    Filed: March 17, 2006
    Publication date: September 28, 2006
    Applicant: NGK Insulators, Ltd.
    Inventors: Yoshimasa Kobayashi, Toru Hayase, Naohito Yamada
  • Publication number: 20060217259
    Abstract: An aluminum nitride sintered body essentially contains aluminum nitride. It contains 0.4 to 2.5 wt % magnesium and 2.0 to 5.0 wt % yttrium, and has an average particle size of not more than 1.0 ?m.
    Type: Application
    Filed: March 17, 2006
    Publication date: September 28, 2006
    Applicant: NGK Insulators, Ltd.
    Inventors: Naomi Teratani, Naohito Yamada
  • Patent number: 7042697
    Abstract: An electrostatic chuck includes a substrate having a wafer-installing face and an opposed back face. An electrostatic chucking electrode is buried in the substrate, and an insulating layer is provided on the back face of the substrate. The substrate also includes a dielectric layer including at least the wafer-installing face and surrounding the electrostatic chucking electrode, and the insulating layer includes an insulating material having a larger volume resistivity than that of the dielectric layer.
    Type: Grant
    Filed: September 30, 2003
    Date of Patent: May 9, 2006
    Assignee: NGK Insulators, Ltd.
    Inventors: Hideyoshi Tsuruta, Naohito Yamada
  • Publication number: 20060019906
    Abstract: Provision of a compound having an anti-HIV activity, particularly an integrase inhibitory activity. A 4-oxoquinoline compound represented by the following formula [I] or a pharmaceutically acceptable salt thereof: wherein each symbol is as defined in the specification.
    Type: Application
    Filed: May 20, 2005
    Publication date: January 26, 2006
    Inventors: Motohide Satoh, Takashi Matsuda, Satoshi Okuda, Hiroshi Kawakami, Hisateru Aramaki, Hisashi Shinkai, Yuji Matsuzaki, Wataru Watanabe, Kazunobu Yamataka, Shinichi Kiyonari, Shuichi Wamaki, Mitsuru Takahashi, Naohito Yamada, Akemi Nagao
  • Publication number: 20060019817
    Abstract: An aluminum nitride ceramic including aluminum nitride grains and grain boundary phases comprises a grain boundary phase-rich layer including more amount of the grain boundary phases in a surface layer of the aluminum nitride ceramic than in an inside of the aluminum nitride ceramic. The grain boundary phases in the grain boundary phase-rich layer include at least one of rare earth element and alkali earth element.
    Type: Application
    Filed: June 15, 2005
    Publication date: January 26, 2006
    Applicant: NGK Insulators, Ltd.
    Inventors: Yoshimasa Kobayashi, Naohito Yamada, Toru Hayase
  • Publication number: 20060006395
    Abstract: There is provided a method for manufacturing an aluminum nitride single crystal, the method including the steps of: preparing a raw material composition containing: aluminum oxide and/or an aluminum oxide precursor which is converted into aluminum oxide by heating, and aluminum nitride and/or an aluminum nitride precursor which is converted into aluminum nitride by heating; heating the raw material composition at 1600 to 2400° C. to synthesize aluminum nitride; and causing crystal growth of the aluminum nitride to obtain an aluminum nitride single crystal. The method is capable of obtaining an aluminum nitride single crystal which is sufficiently large for practical use at low cost in a short time and has high productivity and wide usability.
    Type: Application
    Filed: June 30, 2005
    Publication date: January 12, 2006
    Applicant: NGK Insulators, Ltd.
    Inventors: Yoshimasa Kobayashi, Toru Hayase, Naohito Yamada