Patents by Inventor Kenji Yamaga

Kenji Yamaga 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: 10702944
    Abstract: An alloy structure has an arbitrary shape dimension which has high uniformity in the distribution of the element composition. The alloy structure contains Fe and at least four elements, which are selected from the group consisting of elements from atomic number 13 to atomic number 79 included in Group 3 to Group 16 of the periodic table of the elements and have a ratio of the atomic radius to an Fe atom of 0.83 or more but 1.17 or less, each of Fe and the four elements is contained in an atomic concentration range of 5 at % or more but 30 at % or less, a difference in atomic concentration between at least four elements among the at least four elements and Fe is in a range of less than 3 at %, and the alloy structure has, a column crystal in which the at least four elements and Fe are solid-dissolved.
    Type: Grant
    Filed: July 17, 2015
    Date of Patent: July 7, 2020
    Assignee: HITACHI METALS, LTD.
    Inventors: Takahiko Kato, Kousuke Kuwabara, Tadashi Fujieda, Kinya Aota, Isamu Takahashi, Hiroyuki Satake, Kenji Yamaga, Hajime Murakami
  • Patent number: 10576538
    Abstract: An alloy structure which has high uniformity in the distribution of the element composition and the mechanical strength and excellent high-temperature strength and corrosion resistance, contains Fe and at least four elements, which are selected from the group consisting of elements from atomic number 13 to atomic number 79, included in Group 3 to Group 16 of the periodic table of the elements, and have a ratio of the atomic radius to an Fe atom of 0.83 or more but 1.17 or less, each of the elements in an atomic concentration range of 5 at % or more but 30 at % or less, a difference in atomic concentration among the at least four elements and Fe is in a range of less than 3 at %, and the alloy structure has, as a main crystal, a column crystal in which the at least four elements and Fe are solid-dissolved.
    Type: Grant
    Filed: July 17, 2015
    Date of Patent: March 3, 2020
    Assignee: HITACHI METALS, LTD.
    Inventors: Takahiko Kato, Kousuke Kuwabara, Tadashi Fujieda, Kinya Aota, Isamu Takahashi, Kenji Yamaga, Hiroyuki Satake, Hajime Murakami
  • Publication number: 20190228889
    Abstract: An object of the present invention is to provide a magnetic powder having a narrow particle size distribution of epsilon-type iron oxide particles, and another object is to provide magnetic powder suitable for magnetic recording medium by improving particle size distribution, and provide epsilon-type iron oxide magnetic particles and related technologies in which a number average particle diameter of major diameters (D50) is 10 to 20 nm, a 90% cumulative particle diameter (D90) is 30 nm or less, and a geometric standard deviation (?g) of major diameters is 1.45 or less, which are obtained by TEM observation.
    Type: Application
    Filed: September 29, 2017
    Publication date: July 25, 2019
    Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Kazuhiro YAMAGA, Tetsuya KAWAHITO, Toshihiko UEYAMA, Kenji SAKANE
  • Publication number: 20170209922
    Abstract: An alloy structure which has high uniformity in the distribution of the element composition and the mechanical strength and excellent high-temperature strength and corrosion resistance, contains Fe and at least four elements, which are selected from the group consisting of elements from atomic number 13 to atomic number 79, included in Group 3 to Group 16 of the periodic table of the elements, and have a ratio of the atomic radius to an Fe atom of 0.83 or more but 1.17 or less, each of the elements in an atomic concentration range of 5 at % or more but 30 at % or less, a difference in atomic concentration among the at least four elements and Fe is in a range of less than 3 at %, and the alloy structure has, as a main crystal, a column crystal in which the at least four elements and Fe are solid-dissolved.
    Type: Application
    Filed: July 17, 2015
    Publication date: July 27, 2017
    Applicant: HITACHI, LTD.
    Inventors: Takahiko KATO, Kousuke KUWABARA, Tadashi FUJIEDA, Kinya AOTA, Isamu TAKAHASHI, Kenji YAMAGA, Hiroyuki SATAKE, Hajime MURAKAMI
  • Publication number: 20170209954
    Abstract: An alloy structure has an arbitrary shape dimension which has high uniformity in the distribution of the element composition. The alloy structure contains Fe and at least four elements, which are selected from the group consisting of elements from atomic number 13 to atomic number 79 included in Group 3 to Group 16 of the periodic table of the elements and have a ratio of the atomic radius to an Fe atom of 0.83 or more but 1.17 or less, each of Fe and the four elements is contained in an atomic concentration range of 5 at % or more but 30 at % or less, a difference in atomic concentration between at least four elements among the at least four elements and Fe is in a range of less than 3 at %, and the alloy structure has, a column crystal in which the at least four elements and Fe are solid-dissolved.
    Type: Application
    Filed: July 17, 2015
    Publication date: July 27, 2017
    Applicant: HITACHI, LTD.
    Inventors: Takahiko KATO, Kousuke KUWABARA, Tadashi FUJIEDA, Kinya AOTA, Isamu TAKAHASHI, Hiroyuki SATAKE, Kenji YAMAGA, Hajime MURAKAMI
  • Patent number: 8647784
    Abstract: A fuel cell stack start method is to provide in which without relying on oxidation and reduction condition of an anode, an output reduction of the fuel cell stack can be avoided. In the start method of a solid polymer type fuel cell stack that is comprised of a separator including an anode flow channel for flowing a fuel, another separator including a cathode flow channel for feeding an oxidant and electrodes and an electrolyte interposed between the separators, the method is characterized by performing successively a first step of feeding the fuel to the fuel cell stack under a condition that a cathode is covered by generated water, a second step of forming an oxide layer on the cathode, a third step of feeding the oxidant gas to the fuel cell stack and a fourth step of extracting load current from the fuel cell stack.
    Type: Grant
    Filed: November 18, 2009
    Date of Patent: February 11, 2014
    Assignee: Hitachi, Ltd.
    Inventors: Katsunori Nishimura, Kenji Yamaga, Osamu Kubota, Ko Takahashi
  • Publication number: 20130004869
    Abstract: A fuel cell system having a fuel cell 1, a load 8 connected to the output line of the fuel cell 1 and a control apparatus 20 for controlling an amount of current flowing to the load 8, wherein a stopping state for stopping the fuel cell system includes a first stage stopping state for stopping while remaining hydrogen in the hydrogen line and a second stage stopping state for stopping substituting the hydrogen line with air, and transfers to the second stage stopping state by way of the first stage stopping state.
    Type: Application
    Filed: September 13, 2012
    Publication date: January 3, 2013
    Inventors: Kenji YAMAGA, Hironori Sasaki, Katsunori Nishimura
  • Patent number: 8257874
    Abstract: The fuel cell system includes a fuel cell stack, a fuel cell temperature sensor for measuring the internal temperature of the fuel cell, a voltage sensor for measuring the power generation voltage of the fuel cell, a current sensor for measuring the current flowing from the fuel cell, a radiator for radiating heat generated by the fuel cell, a fan attached to the radiator for controlling the heat radiation amount, a cooling water pump for increasing the pressure of a cooling fluid, a bypass valve for controlling the cooling fluid amount entering the radiator, and a controller, on the basis of the voltage information measured by the voltage sensor, the temperature information measured by the temperature sensor, and the current information measured by the current sensor, for controlling at least one of the operation amount of the cooling water pump, the operation amount of the fan, and the cooling fluid amount flowing through the bypass valve.
    Type: Grant
    Filed: October 25, 2010
    Date of Patent: September 4, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Kenji Yamaga, Hironori Sasaki
  • Patent number: 8197987
    Abstract: A separator for fuel cell comprising an electrolyte with ionic conductivity, a pair of electrodes with the electrolyte sandwiched therebetween, and a separator 10 for individually supplying a fuel gas and an oxidizing agent gas to the pair of the electrodes, respectively, wherein the separator 10 is provided with a multilayered metal sheet with at least the outermost layer thereof, and a corrosion-resistant film covering the whole surface of the metal sheet in order to form a metal separator, and the metal separator is further provided with a reacting gas sealing unit 21, a reacting gas manifold junction unit 22, and a reacting gas rectification unit 23, formed of an elastic body.
    Type: Grant
    Filed: January 25, 2007
    Date of Patent: June 12, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Hironori Sasaki, Kenji Yamaga, Katsunori Nishimura
  • Publication number: 20120107722
    Abstract: A separator for a fuel cell includes a metal separator (metal substrate) having projections formed by ribs, and porous members provided in a plurality of flow passages partitioned by the projections, in which a hydrophilic portion is provided in a center part of a cross section orthogonal to a flow direction in the porous member, and a water repellent portion is provided in at least a part of portions in contact with wall surfaces of the flow passage within a range of the cross section. According to the present invention, the mixed phase flow in which the reaction gas and the cooling water inside the flow passages are mixed can be made an even flow in the separator in which the porous members are provided in the gas flow passages.
    Type: Application
    Filed: November 1, 2011
    Publication date: May 3, 2012
    Inventors: Hiroyuki SATAKE, Masaya KOZAKAI, Kenji YAMAGA
  • Patent number: 8137856
    Abstract: Excellent gas sealing properties were difficult to achieve with a structure that uses a meal material to control material cost and does not increase the number of components. A cell is configured by using a metal separator having at least one protruding structure between a manifold and an electrode channel, and having a communicating channel structure that forms a fluid circulating space by being folded back at the side containing a connection so that the tip of the protruding structure is in contact with a surface of the separator. Accordingly, a gas channel from the manifold to an electrode surface can be easily formed integrally. This can be applied to a metal material easily. Further, the present invention can provide excellent gas sealing properties.
    Type: Grant
    Filed: February 13, 2009
    Date of Patent: March 20, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Kenji Yamaga, Tsutomu Okusawa, Masaya Kozakai
  • Patent number: 7952984
    Abstract: An optical recording medium and a method of recording and reproducing of the optical recording medium are provided, which are capable of recording and reproducing data with reliability even when blue or blue violet laser light is used as irradiation light. The optical recording medium has a recording layer in which a recording mark composed of a plurality of cavities is formed by irradiation of the laser light. The recording layer is configured so that, in a plan view taken in a direction of irradiation of the laser light, cavities lying in an area of the center and its vicinities of the recording mark, out of the plurality of cavities, include cavities greater than ones lying around the area.
    Type: Grant
    Filed: April 22, 2005
    Date of Patent: May 31, 2011
    Assignee: TDK Corporation
    Inventors: Koji Mishima, Kenji Yamaga, Daisuke Yoshitoku
  • Patent number: 7932015
    Abstract: An optical recording medium includes a substrate and a plurality of recording layers laminated via at least intermediate layers, at least one of the recording layers other than a recording layer farthest from a light incidence plane among the plurality of recording layers containing at least one metal M selected from a group consisting of Ni, Cu, Si, Ti, Ge, Zr, Nb, Mo, In, Sn, W, Pb, Bi, Zn and La and an element X which can combine with the metal M upon being irradiated with a laser beam for recording data, thereby forming a crystal of a compound of the element X with the metal M. According to the thus constituted optical recording medium, it is possible to record data in and reproduce from a farthest recording layer from a light incidence plane in a desired manner and it is possible to record data in and reproduce from recording layer(s) other than the farthest recording layer from the light incidence plane in a desired manner.
    Type: Grant
    Filed: December 30, 2003
    Date of Patent: April 26, 2011
    Assignee: TDK Corporation
    Inventors: Koji Mishima, Hiroyasu Inoue, Tsuyoshi Komaki, Daisuke Yoshitoku, Hitoshi Arai, Kenji Yamaga, Hironori Kakiuchi
  • Publication number: 20110065013
    Abstract: A fuel cell stack start method is to provide in which without relying on oxidation and reduction condition of an anode, an output reduction of the fuel cell stack can be avoided. In the start method of a solid polymer type fuel cell stack that is comprised of a separator including an anode flow channel for flowing a fuel, another separator including a cathode flow channel for feeding an oxidant and electrodes and an electrolyte interposed between the separators, the method is characterized by performing successively a first step of feeding the fuel to the fuel cell stack under a condition that a cathode is covered by generated water, a second step of forming an oxide layer on the cathode, a third step of feeding the oxidant gas to the fuel cell stack and a fourth step of extracting load current from the fuel cell stack.
    Type: Application
    Filed: November 18, 2009
    Publication date: March 17, 2011
    Inventors: Katsunori Nishimura, Kenji Yamaga, Osamu Kubota, Ko Takahashi
  • Publication number: 20110039177
    Abstract: The fuel cell system includes a fuel cell stack, a fuel cell temperature sensor for measuring the internal temperature of the fuel cell, a voltage sensor for measuring the power generation voltage of the fuel cell, a current sensor for measuring the current flowing from the fuel cell, a radiator for radiating heat generated by the fuel cell, a fan attached to the radiator for controlling the heat radiation amount, a cooling water pump for increasing the pressure of a cooling fluid, a bypass valve for controlling the cooling fluid amount entering the radiator, and a controller, on the basis of the voltage information measured by the voltage sensor, the temperature information measured by the temperature sensor, and the current information measured by the current sensor, for controlling at least one of the operation amount of the cooling water pump, the operation amount of the fan, and the cooling fluid amount flowing through the bypass valve.
    Type: Application
    Filed: October 25, 2010
    Publication date: February 17, 2011
    Inventors: Kenji YAMAGA, Hironori Sasaki
  • Publication number: 20100291448
    Abstract: There is provided a fuel cell system capable of minimizing the formation of a local cell even if the start and the stop are repeated, thereby substantially reducing a degradation in performance of the fuel cell. The fuel cell system includes a fuel cell; a hydrogen supply unit for supplying hydrogen to an anode channel of the fuel cell; an air-amount adjusting unit for adjusting the amount of air supplied to a cathode channel of the fuel cell and discharged from the cathode channel; an external load connected to the fuel cell; and a control unit for controlling an operation of the hydrogen supply unit, the air-amount adjusting unit, and the external load; in which the control unit controls the fuel cell system such that the cathode channel of the fuel cell is filled with air whose pressure is not higher than a saturated vapor pressure at the time of starting the fuel cell system, thereafter, the air is continuously led through the cathode channel of the fuel cell, and a load is drawn from the fuel cell.
    Type: Application
    Filed: May 13, 2010
    Publication date: November 18, 2010
    Inventors: Kenji Yamaga, Katsunori Nishimura, Osamu Kubota
  • Publication number: 20100209803
    Abstract: Excellent gas sealing properties were difficult to achieve with a structure that uses a meal material to control material cost and does not increase the number of components. A cell is configured by using a metal separator having at least one protruding structure between a manifold and an electrode channel, and having a communicating channel structure that forms a fluid circulating space by being folded back at the side containing a connection so that the tip of the protruding structure is in contact with a surface of the separator. Accordingly, a gas channel from the manifold to an electrode surface can be easily formed integrally. This can be applied to a metal material easily. Further, the present invention can provide excellent gas sealing properties.
    Type: Application
    Filed: February 13, 2009
    Publication date: August 19, 2010
    Inventors: Kenji YAMAGA, Tsutomu Okusawa, Masaya Kozakai
  • Patent number: 7745032
    Abstract: The fuel cell assembly disclosed includes at least one unit fuel cell comprising a separator having flow channels for oxidizing gas, a cathode to which the oxidizing gas is fed, a membrane electrolyte of proton conductivity, an anode to which fuel gas is fed, and a separator having flow channels for the fuel gas, the above members being arranged in order. The fuel cell assembly further comprises a humidifier having a porous member to humidify at least the fuel gas to be fed to the anode. The porous member of the humidifier is so disposed as to face at least the flow channels for the oxidizing gas so that water is supplied to the flow channels from part of the surface of the porous member opposite to the water supplying face and/or from the outer periphery of the porous member.
    Type: Grant
    Filed: October 16, 2003
    Date of Patent: June 29, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Katsunori Nishimura, Jinichi Imahashi, Kenji Yamaga, Masahiro Komachiya, Makoto Morishima
  • Patent number: 7745035
    Abstract: A separator for a fuel cell, comprising a planar panel formed therein with a plurality of manifolds for passing reactive fluid or cooling medium through adjacent cell, and a pair of conductive passage boards superposed with one another, interposing therebetween the planar panel, the passage boards being formed therein with a plurality of meandering through channels for distributing the reactive fluid or the cooling medium from the manifolds, wherein the planar panel being formed therein with slits through which channel defining walls of the meandering through channels of the fluid passages are electrically connected with each other.
    Type: Grant
    Filed: November 24, 2008
    Date of Patent: June 29, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Hiroshi Yamauchi, Kenji Yamaga, Ko Takahashi
  • Patent number: 7680018
    Abstract: An optical recording medium including a light transmitting layer having a uniform thickness formed on a substrate, in which a burr or stripping hardly occurs at the inner periphery of the light transmitting layer, and a manufacturing method and a manufacturing device of the optical recording medium are provided. An optical recording medium 10 is manufactured by a manufacturing method including: molding a disc-like shaped substrate 12 including an information recording face 12A on one side; forming a light transmitting layer 14 thinner than the substrate 12 on the information recording face 12A; forming a circular cut 16 in the light transmitting layer 14; and punching out an area inside the cut 16 by a punching tool 18 to form a center hole 14A in the light transmitting layer 14 and a center hole 20 in the substrate 12.
    Type: Grant
    Filed: June 6, 2003
    Date of Patent: March 16, 2010
    Assignee: TDK Corporation
    Inventors: Tomoki Ushida, Mamoru Usami, Kenji Yamaga