Patents by Inventor Takefumi Yokokura

Takefumi Yokokura 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: 8496819
    Abstract: Both a column having high-pressure resistance and capable of performing high-speed separation and analysis even with a small flow rate and a liquid chromatograph apparatus using the column are provided. A separation column according to the present invention has a monolithic rod being arranged in the center, being made of a porous material, and having a circular cross section, a filler layer arranged such that it encircles a circumferential surface of the monolithic rod, and a cylindrical support medium arranged outside the filler layer. The filler layer is formed by filling a tube-like gap between the monolithic rod and the support medium with particles or beads.
    Type: Grant
    Filed: June 26, 2008
    Date of Patent: July 30, 2013
    Assignee: Hitachi High-Technologies Corporation
    Inventors: Katsutoshi Shimizu, Masahito Ito, Kimihiko Ishii, Yoshihiro Nagaoka, Kisaburo Deguchi, Takefumi Yokokura
  • Patent number: 8319194
    Abstract: The mass spectrometer includes an ion source; a mass spectrometry part; a sample container; a heater for the sample container; a first gas tube connected to the sample container to introduce a gas into the sample container; and a second gas tube connected to the sample container to transfer a headspace gas of the sample container to the ion source, in which the ion source generates ions of the headspace gas and the mass spectrometry part performs mass spectrometry of the ions. Thereby, the mass spectrometer as a drug detection equipment can analyze various drugs in urine rapidly and with high sensitivity.
    Type: Grant
    Filed: August 22, 2011
    Date of Patent: November 27, 2012
    Assignee: Hitachi High-Technologies Corporation
    Inventors: Makoto Hashimoto, Takefumi Yokokura, Masuyoshi Yamada, Hiroyuki Inoue, Hidetoshi Morokuma
  • Publication number: 20120049055
    Abstract: The mass spectrometer includes an ion source; a mass spectrometry part; a sample container; a heater for the sample container; a first gas tube connected to the sample container to introduce a gas into the sample container; and a second gas tube connected to the sample container to transfer a headspace gas of the sample container to the ion source, in which the ion source generates ions of the headspace gas and the mass spectrometry part performs mass spectrometry of the ions. Thereby, the mass spectrometer as a drug detection equipment can analyze various drugs in urine rapidly and with high sensitivity.
    Type: Application
    Filed: August 22, 2011
    Publication date: March 1, 2012
    Inventors: Makoto Hashimoto, Takefumi Yokokura, Masuyoshi Yamada, Hiroyuki Inoue, Hidetoshi Morokuma
  • Patent number: 8123496
    Abstract: A pump device which accurately detects a flow rate of a pump, performs real-time control of the flow rate, and thus can suppress a flow rate error caused by occurrence of pulsation. Control of a pump rotation speed by a pressure sensor has low responsiveness in a low pressure region, and a correlation between a pressure and a flow rate is incomplete in a high flow rate region. With this taken into consideration, a flow rate sensor is disposed at an outlet port of a second pump. A position detection sensor detects a point where a first pump is shifted from a suction mode to a discharge mode. Moreover, the flow rate sensor detects that there is no discharge from the pump, and that there is discharge from the pump alone. Accordingly, a controller sets a rotation speed of a motor to a speed double the previous speed (double the normal rotation speed).
    Type: Grant
    Filed: July 28, 2010
    Date of Patent: February 28, 2012
    Assignee: Hitachi High-Technologies Corporation
    Inventors: Kimihiko Ishii, Kiyotoshi Mori, Masahito Ito, Hironori Kaji, Takefumi Yokokura
  • Publication number: 20110248157
    Abstract: Objects of the present invention is to provide a quadrupole mass filter that can be fabricated at low cost and has a high transmission efficiency even under a high pressure (0.5 mTorr or more), and to provide a mass spectrometer or mass spectrometry method that reduces crosstalk in a wide mass range. Now, in a mass spectrometer, an ion separating unit is configured to include quadrupole rod electrodes that form a quadrupole radio-frequency electric field, electrodes that form a quadrupole electrostatic field, and a power supply that allows the voltage of the electrodes to form a quadrupole electrostatic field to change. In a collision cell configured to perform collision induced dissociation, harmonic potentials in a plurality of stages are produced to resonance excite ions in the axial direction, so that the ions obtain kinetic energy to move in the direction of the detector. This energy allows a time period to shorten for which ions stay in the collision cell.
    Type: Application
    Filed: October 13, 2009
    Publication date: October 13, 2011
    Inventors: Masuyuki Sugiyama, Yuichiro Hashimoto, Hideki Hasegawa, Masuyoshi Yamada, Hiroyuki Yasuda, Shinji Nagai, Shintaro Kubo, Takefumi Yokokura
  • Publication number: 20100288027
    Abstract: A pump device is realized, which accurately detects a flow rate of a pump, performs real-time control of the flow rate, and thus can suppress a flow rate error caused by occurrence of pulsation. Control of a pump rotation speed by a pressure sensor has low responsiveness in a low pressure region, and a correlation between a pressure and a flow rate is incomplete in a high flow rate region. With this taken into consideration, a flow rate sensor 10 is disposed at an outlet port 9 of a second pump 4. A position detection sensor 14 detects a point where a first pump 3 is shifted from a suction mode to a discharge mode. Moreover, the flow rate sensor 10 detects that there is no discharge from the pump 3, and that there is discharge from the pump 4 alone. Accordingly, a controller 15 sets a rotation speed of a motor 12 to a speed double the previous speed (double the normal rotation speed).
    Type: Application
    Filed: July 28, 2010
    Publication date: November 18, 2010
    Applicant: Hitachi High-Technologies Corporation
    Inventors: Kimihiko Ishii, Kiyotoshi Mori, Masahito Ito, Hironori Kaji, Takefumi Yokokura
  • Publication number: 20090001007
    Abstract: Both a column having high-pressure resistance and capable of performing high-speed separation and analysis even with a small flow rate and a liquid chromatograph apparatus using thereof are to be provided. A separation column according to the present invention has a monolithic rod being arranged in the center, being made of a porous material, and having a circular cross section, a filler layer arranged such that it encircles a circumferential surface of the monolithic rod, and a cylindrical support medium arranged outside the filler layer. The filler layer is formed by filling a tube-like gap between the monolithic rod and the support medium with particles or beads.
    Type: Application
    Filed: June 26, 2008
    Publication date: January 1, 2009
    Inventors: Katsutoshi Shimizu, Masahito Ito, Kimihiko Ishii, Yoshihiro Nagaoka, Kisaburo Deguchi, Takefumi Yokokura
  • Publication number: 20070084766
    Abstract: A pump device is realized, which accurately detects a flow rate of a pump, performs real-time control of the flow rate, and thus can suppress a flow rate error caused by occurrence of pulsation. Control of a pump rotation speed by a pressure sensor has low responsiveness in a low pressure region, and a correlation between a pressure and a flow rate is incomplete in a high flow rate region. With this taken into consideration, a flow rate sensor 10 is disposed at an outlet port 9 of a second pump 4. A position detection sensor 14 detects a point where a first pump 3 is shifted from a suction mode to a discharge mode. Moreover, the flow rate sensor 10 detects that there is no discharge from the pump 3, and that there is discharge from the pump 4 alone. Accordingly, a controller 15 sets a rotation speed of a motor 12 to a speed double the previous speed (double the normal rotation speed).
    Type: Application
    Filed: October 18, 2006
    Publication date: April 19, 2007
    Inventors: Kimihiko Ishii, Kiyotoshi Mori, Masahito Ito, Hironori Kaji, Takefumi Yokokura
  • Patent number: 5378635
    Abstract: A method of measuring at least one of a catecholamine and its metabolite including a biological sample pretreatment process, a fluorescence inducing process of converting into a fluorescence inductor the at least one of a catecholamine and its metabolite in the biological sample subjected to pretreatment by means of a fluorescence inducing reagent, and a measuring process of separating and measuring said fluorescence inductor by liquid chromatography, said method being characterized by addition of a specified volume of maleimide before said process of making the biological sample fluorescent.
    Type: Grant
    Filed: October 6, 1993
    Date of Patent: January 3, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Kenji Yasuda, Masami Aoki, Takefumi Yokokura