Patents by Inventor Keiji Yamahara

Keiji Yamahara 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: 11939504
    Abstract: The present invention aims to provide a scintillator which has a short fluorescence decay time, whose fluorescence intensity after a period of time following radiation irradiation is low, and which shows largely improved light-transmittance. A scintillator represented by the following General Formula (1), the scintillator including Zr, having a Zr content of not less than 1500 ppm by mass therein, and being a block of a sintered body. QxMyO3z:A . . . (1) (wherein in General Formula (1), Q includes at least one or more kinds of divalent metallic elements; M includes at least Hf; and x, y, and z independently satisfy 0.5?x?1.5, 0.5?y?1.5, and 0.7?z?1.5, respectively).
    Type: Grant
    Filed: June 23, 2022
    Date of Patent: March 26, 2024
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Koji Hazu, Kentaro Horibe, Tetsuya Kawano, Keiji Yamahara, Shunsuke Kurosawa, Akira Yoshikawa
  • Publication number: 20240019592
    Abstract: A scintillator, having a composition represented by the following general formula (1), including a substitution element A, the substitution element A comprising at least La, and a total molar content of the substitution element A being 0.00001 mol or more and 0.05 mol or less in 1 mol of the scintillator, and further including an activator element B, the activator element B being constituted from Ce, having a perovskite-type crystal structure, and exhibiting a linear transmittance of light at a wavelength of 800 nm, at a thickness of 1.9 mm, of 30% or more. QMxO3y . . . (1): wherein Q represents one or more elements selected from the group consisting of Ca, Sr and Ba; M represents Hf; Q and M are each optionally substituted with other element at a proportion of 20% by mol or less; and x and y respectively satisfy 0.5?x?1.5 and 0.7?y?1.5.
    Type: Application
    Filed: September 26, 2023
    Publication date: January 18, 2024
    Applicants: Mitsubishi Chemical Corporation, TOHOKU UNIVERSITY
    Inventors: Koji Hazu, Keiji Yamahara, Shunsuke Kurosawa, Akira Yoshikawa
  • Publication number: 20230218249
    Abstract: The signal processing system generates image data, based on an electric signal group output from a radiation detector, and recognizes the electric signal group as a processing target, and the electric signal group includes at least part of an electric signal group meeting the following requirements: the electric signal group is an electric signal group with a signal value within a predetermined range, the electric signal group corresponding to a gamma ray with energy equal to or less than 375 keV; the predetermined range is equal to or greater than 50% and equal to or less than 80% relative to a 100% signal value; and the 100% signal value is a signal value detected when a gamma ray with energy of 511 keV enters a radiation detection element in the radiation detector and is totally absorbed by the radiation detection element.
    Type: Application
    Filed: March 8, 2023
    Publication date: July 13, 2023
    Applicants: Mitsubishi Chemical Corporation, Tohoku University
    Inventors: Koji Hazu, Kentaro Horibe, Keiji Yamahara, Shunsuke Kurosawa, Akira Yoshikawa
  • Publication number: 20220363987
    Abstract: An object of the present invention is to provide a scintillator having a high radiation stopping power, and having a shorter fluorescence decay time compared to conventional scintillators. The above object is achieved by setting the composition of a scintillator to a composition represented by General Formula (1). QxMyO3z??(1) (wherein in General Formula (1), Q includes at least two or more divalent metallic elements; M includes at least Hf; and x, y, and z independently satisfy 0.5?x?1.5, 0.5?y?1.5, and 0.7?z?1.5, respectively).
    Type: Application
    Filed: July 19, 2022
    Publication date: November 17, 2022
    Applicants: Mitsubishi Chemical Corporation, Tohoku University
    Inventors: Koji Hazu, Kentaro Horibe, Keiji Yamahara, Sunsuke Kurosawa, Akira Yoshikawa
  • Publication number: 20220326400
    Abstract: The present invention aims to provide a scintillator which has a short fluorescence decay time, whose fluorescence intensity after a period of time following radiation irradiation is low, and which shows largely improved light-transmittance. A scintillator represented by the following General Formula (1), the scintillator including Zr, having a Zr content of not less than 1500 ppm by mass therein, and being a block of a sintered body. QxMyO3z:A . . . (1) (wherein in General Formula (1), Q includes at least one or more kinds of divalent metallic elements; M includes at least Hf; and x, y, and z independently satisfy 0.5?x?1.5, 0.5?y?1.5, and 0.7?z?1.5, respectively).
    Type: Application
    Filed: June 23, 2022
    Publication date: October 13, 2022
    Applicants: Mitsubishi Chemical Corporation, Tohoku University
    Inventors: Koji Hazu, Kentaro Horibe, Tetsuya Kawano, Keiji Yamahara, Shunsuke Kurosawa, Akira Yoshikawa
  • Publication number: 20220176341
    Abstract: Provided is a metal oxide containing a brownmillerite-type manganese oxide represented by (Ca2-xAx)(MnyAlzE2-y-z)wO5+? (in the formula, A represents one or more alkaline earth metal elements other than Ca; E represents one or more 3d transition metal elements or earth metal elements other than Mn and Al; and x, y, z, ?, and w satisfy 0?x?2, 0<y?2, 0?z<2, 0<y+z?2, 0???0.5, and 0.8?w?1.2), wherein the metal oxide has a defect in a (020) plane of a crystal of the brownmillerite-type manganese oxide.
    Type: Application
    Filed: February 25, 2022
    Publication date: June 9, 2022
    Applicants: Mitsubishi Chemical Corporation, KANAGAWA UNIVERSITY
    Inventors: Ryo NISHIDA, Keiji YAMAHARA, Teruki MOTOHASHI, Miwa SAITO, Sayaka TAMURA, Tomohiro ISEKI
  • Patent number: 11261376
    Abstract: The present invention provides a gadolinium oxysulfide sintered body having a high light output. The problem is resolved by a gadolinium oxysulfide sintered body in which the ratio of the light transmittance T410 of 410 nm to the light transmittance T512 of 512 nm (T410/T512) is from 0.31 to 0.61, or a gadolinium oxysulfide sintered body in which the ratio of the diffraction peak intensity Iy of a phase different from gadolinium oxysulfide appearing at 2?=from 20 to 29° to the diffraction peak intensity (Ix) of (102) or (011) of gadolinium oxysulfide appearing at 2?=30°±1° (Iy/Ix) is 0.1 or less in an XRD diffraction pattern and which contains one or more activators selected from the group consisting of praseodymium, terbium, and cerium.
    Type: Grant
    Filed: July 25, 2019
    Date of Patent: March 1, 2022
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Koji Hazu, Keiji Yamahara, Toshiaki Katayama
  • Publication number: 20190345383
    Abstract: The present invention provides a gadolinium oxysulfide sintered body having a high light output. The problem is resolved by a gadolinium oxysulfide sintered body in which the ratio of the light transmittance T410 of 410 nm to the light transmittance T512 of 512 nm (T410/T512) is from 0.31 to 0.61, or a gadolinium oxysulfide sintered body in which the ratio of the diffraction peak intensity Iy of a phase different from gadolinium oxysulfide appearing at 2?=from 20 to 29° to the diffraction peak intensity (Ix) of (102) or (011) of gadolinium oxysulfide appearing at 2?=30°±1° (Iy/Ix) is 0.1 or less in an XRD diffraction pattern and which contains one or more activators selected from the group consisting of praseodymium, terbium, and cerium.
    Type: Application
    Filed: July 25, 2019
    Publication date: November 14, 2019
    Applicant: Mitsubishi Chemical Corporation
    Inventors: Koji HAZU, Keiji Yamahara, Toshiaki Katayama
  • Publication number: 20130001816
    Abstract: A method for recovering or producing silicon, that can recover or produce silicon using cutting scraps containing silicon carbide abrasive grains and silicon as raw materials without separating those is provided. The present invention is a method for recovering or producing silicon from cutting scraps containing silicon carbide, which are produced during a cutting or grinding of silicon ingots or silicon wafers, wherein the method comprises producing silicon by heating the cutting scraps containing silicon carbide, and a silica raw material.
    Type: Application
    Filed: September 11, 2012
    Publication date: January 3, 2013
    Applicant: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Keiji Yamahara, Toshiaki Katayama, Tadashi Hashiguchi, Toshiki Shirahama, Takeshi Sawai
  • Publication number: 20130004908
    Abstract: The present invention provides a method for producing silicon by at least heating any one of raw materials for silicon production selected from a silica raw material and a carbon material; a silica raw material and silicon carbide; and silicon raw material, in a heating furnace, wherein the method comprises operating at least one of the raw materials for silicon production and a heated product in the heating furnace using a jig, and the jig comprises a non-metallic material portion having a bending strength of 100 MPa or more and a melting point higher than a melting point of silicon, and at least a portion thereof coming into contact with the raw materials for silicon production or the heated product, having a temperature of 1,000° C. or higher, is constituted of the non-metallic material portion.
    Type: Application
    Filed: September 11, 2012
    Publication date: January 3, 2013
    Applicant: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Toshiaki KATAYAMA, Keiji YAMAHARA
  • Patent number: 8309272
    Abstract: A solid oxide cell is provided which, after short-time activation, can generate electricity at a high power density over a prolonged period. This cell can be constituted so as to eliminate the necessity of carrier gas introduction during power generation and, hence, can more easily realize a size reduction in power generation systems. The solid oxide cell at least has an anode having an anode material, a cathode having a cathode material, and an electrolyte disposed between the anode and the cathode and including an ionically conductive solid oxide, wherein the anode material includes a composite metal oxide or a cermet, solid carbon is deposited on the anode material during activation and at least the following reaction schemes (1) and (2) are utilized at the anode during power generation to generate electricity.
    Type: Grant
    Filed: February 27, 2007
    Date of Patent: November 13, 2012
    Assignees: Tokyo Institute of Technology, Mitsubishi Chemical Corporation
    Inventors: Manabu Ihara, Shinichi Hasegawa, Keiji Yamahara
  • Publication number: 20120211350
    Abstract: Processes or apparatuses for producing silicon by a carbon reduction in an arc furnace using a raw silica material having an iron content, an aluminum content, a calcium content, and a titanium content of 0.1% by mass or less, respectively and using a carbon material, wherein during the carbon reduction, an overcurrent which flows through an electrode of the arc furnace is mitigated using a power regulation unit or that the arc furnace is operated at a hearth power density PD (W/cm2) of 90 (W/cm2) or higher.
    Type: Application
    Filed: April 5, 2012
    Publication date: August 23, 2012
    Applicant: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Keiji Yamahara, Hiromi Fujimoto, Toshiaki Katayama
  • Publication number: 20100150551
    Abstract: If opening and deleting of arbitrary optical pathways are repeated in a configuration where plural OADM nodes are connected to each other in a ring manner, empty waves in the ring are fragmented, and thus, it is necessary to optimize the optical pathways. When an optical pathway is opened from an OADM node to a different OADM node, transponders capable of connecting two routes to the OADM nodes and of setting different wavelengths for two routes are mounted in a state where there are no empty waves on a part of the route, so that an already-opened optical pathway is detoured to a detour route or a different wavelength in the OADM ring, and continuous empty waves are produced in a section to be opened so as to open a new optical pathway.
    Type: Application
    Filed: December 3, 2009
    Publication date: June 17, 2010
    Inventors: Keiji YAMAHARA, Kenji KATAOKA, Shuji MAEDA, Hitoshi IHARA, Eriko SUGIOKA
  • Publication number: 20100035099
    Abstract: A solid oxide cell is provided which, after short-time activation, can generate electricity at a high power density over a prolonged period. This cell can be constituted so as to eliminate the necessity of carrier gas introduction during power generation and, hence, can more easily realize a size reduction in power generation systems. The solid oxide cell at least has an anode having an anode material, a cathode having a cathode material, and an electrolyte disposed between the anode and the cathode and including an ionically conductive solid oxide, wherein the anode material includes a composite metal oxide or a cermet, solid carbon is deposited on the anode material during activation and at least the following reaction schemes (1) and (2) are utilized at the anode during power generation to generate electricity.
    Type: Application
    Filed: February 27, 2007
    Publication date: February 11, 2010
    Applicants: Tokyo Institute of Technology, Mitsubishi Chemical Corporation
    Inventors: Manabu Ihara, Shinichi Hasegawa, Keiji Yamahara
  • Patent number: 7427387
    Abstract: Subjects for the invention are to obtain a quartz powder having a high purity and high quality and a process for producing the same and to obtain a glass molding formed by melting and molding the powder and extremely reduced in bubble inclusion. The invention provides a quartz powder, preferably a synthetic quartz powder obtained by the sol-gel method, which, upon heating from room temperature to 1,700° C., generates gases in which the amount of CO is 300 nl/g or smaller and the amount of CO2 is 30 nl/g or smaller.
    Type: Grant
    Filed: April 18, 2006
    Date of Patent: September 23, 2008
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Yoshio Katsuro, Keiji Yamahara, Takashi Yamaguchi, Yutaka Mori
  • Publication number: 20060183624
    Abstract: Subjects for the invention are to obtain a quartz powder having a high purity and high quality and a process for producing the same and to obtain a glass molding formed by melting and molding the powder and extremely reduced in bubble inclusion. The invention provides a quartz powder, preferably a synthetic quartz powder obtained by the sol-gel method, which, upon heating from room temperature to 1,700° C., generates gases in which the amount of CO is 300 nl/g or smaller and the amount of CO2 is 30 nl/g or smaller.
    Type: Application
    Filed: April 18, 2006
    Publication date: August 17, 2006
    Applicant: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Yoshio Katsuro, Keiji Yamahara, Takashi Yamaguchi, Yutaka Mori
  • Patent number: 7063826
    Abstract: Subjects for the invention are to obtain a quartz powder having a high purity and high quality and a process for producing the same and to obtain a glass molding formed by melting and molding the powder and extremely reduced in bubble inclusion. The invention provides a quartz powder, preferably a synthetic quartz powder obtained by the sol-gel method, which, upon heating from room temperature to 1,700° C., generates gases in which the amount of CO is 300 nl/g or smaller and the amount of CO2 is 30 nl/g or smaller.
    Type: Grant
    Filed: January 16, 2004
    Date of Patent: June 20, 2006
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Yoshio Katsuro, Keiji Yamahara, Takashi Yamaguchi, Yutaka Mori
  • Publication number: 20040161375
    Abstract: Subjects for the invention are to obtain a quartz powder having a high purity and high quality and a process for producing the same and to obtain a glass molding formed by melting and molding the powder and extremely reduced in bubble inclusion.
    Type: Application
    Filed: January 16, 2004
    Publication date: August 19, 2004
    Applicant: MITSUBISHI CHEMICAL CORPORATION
    Inventors: Yoshio Katsuro, Keiji Yamahara, Takashi Yamaguchi, Yutaka Mori