Patents by Inventor Tetsuo Nakazawa

Tetsuo Nakazawa 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: 5987091
    Abstract: Projection data having a phase difference of 180.degree. from each other, which are obtained through a 1/4 offset detector, are arranged alternately to obtain projection data of the high resolution, and a CT image is reconstructed on the basis of the projection data of the high resolution. Opposition difference data showing the difference between the projection data having the phase difference of 180.degree. from each other and having a phase difference of 180.degree. from each other are alternately arranged to obtain the opposition difference data of the high resolution, and an opposition difference image is reconstructed on the basis of the opposition difference data of the high resolution. Then, distortion components showing the high-frequency component are extracted from the aforesaid opposition difference image, and the aforesaid reconstructed CT image is corrected by the thus extracted distortion components, so that motion artifacts contained in the original CT image can be reduced.
    Type: Grant
    Filed: July 21, 1997
    Date of Patent: November 16, 1999
    Assignee: Hitachi Medical Corporation
    Inventors: Osamu Miyazaki, Shinichi Migita, Tetsuo Nakazawa
  • Patent number: 5615279
    Abstract: In a scattered X-ray correction method for an X-ray computerized tomograph, the quantity of X-rays passed through a phantom is measured to be converted into logarithms. Obtained from the logarithmic data is a scattered X-ray correction curve representing a relationship between the measured data in the logarithmic expression and an amount of scattered X-ray correction. For a subject, the quantity of X-rays penetrated therethrough is measured to be transformed into logarithms. From the measured data undergone the logarithmic conversion and the scattered X-ray correction curve, there is attained a scattered X-ray correction amount in a linear region which is the state before the logarithmic conversion. The measured data of the subject in the logarithmic expression is subjected to an inverse logarithmic conversion.
    Type: Grant
    Filed: November 1, 1994
    Date of Patent: March 25, 1997
    Assignee: Hitachi Medical Corporation
    Inventors: Tomonori Yoshioka, Shinichi Migita, Tetsuo Nakazawa
  • Patent number: 5460877
    Abstract: A method of treating a metal alkoxide solution to form metal oxide prepolymer molecules therein is characterized by irradiating the solution with light energy having a wavelength selected to break the metal-alkoxy group bond in said metal alkoxide, thereby to form the metal oxide prepolymer molecules in the solution. The prepolymer is converted into polymeric metal oxide gel. The stoichiometry of the oxide is high. A gel of carbon content below 4 atomic % can be achieved by the step of decarbonizing the gel, preferably using light to produce ozone.
    Type: Grant
    Filed: April 18, 1994
    Date of Patent: October 24, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Tomoji Oishi, Ken Takahashi, Tetsuo Nakazawa, Shigeru Tanaka, Tadahiko Miyoshi
  • Patent number: 5449948
    Abstract: Integrated circuit devices, chips and methods of making and operating them are disclosed. The devices are specially adapted for high frequency operation e.g. at or above 1 GHz. Inductive noise caused by switching at these frequencies--and which can interfere with switching--is inhibited by using a large bypass capacitor connected between power and ground connections outside the chip, and a small bypass capacitor connected between the same power and ground connections but formed inside the chip. The smaller capacitor cuts noise attributable to the wiring between the larger capacitor and the chip. The chip can have many of the smaller capacitors, even one or more per gate. In the preferred embodiments, the small capacitors from power and ground bonding pads are formed at the front surface of the chip substrate. Tantalum pentoxide, and other suitable dielectrics having relative dielectric constant of 10 or more at 1 GHz, are used to form the capacitors.
    Type: Grant
    Filed: April 1, 1991
    Date of Patent: September 12, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Hirokazu Inoue, Tomoji Oishi, Hiroichi Shinohara, Ken Takahashi, Tetsuo Nakazawa, Mitsuo Usami, Masaki Fukuoka
  • Patent number: 5234556
    Abstract: A method of treating a metal alkoxide solution to form metal oxide prepolymer molecules therein is characterized by irradiating the solution with light energy having a wavelength selected to break the metal-alkoxy group bond in said metal alkoxide, thereby to form the metal oxide prepolymer molecules in the solution. The prepolymer is converted into polymeric metal oxide gel. The stoichiometry of the oxide is high. A gel of carbon content below 4 atomic % can be achieved by the step of decarbonizing the gel, preferably using light to produce ozone.
    Type: Grant
    Filed: August 20, 1990
    Date of Patent: August 10, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Tomoji Oishi, Ken Takahashi, Tetsuo Nakazawa, Shigeru Tanaka, Tadahiko Miyoshi
  • Patent number: 5182075
    Abstract: A structure of a nuclear fusion reactor having a vacuum vessel in which hydrogen isotope plasma is enclosed and a confining magnetic field generating coil for confining said plasma at a predetermined position in said vacuum vessel. It comprises a low tritium-permeable layer having lower tritium-permeability than that of a cooling metal base for forming a refrigerant passage for cooling the vacuum vessel on at least the surface adjacent to said plasma enclosed and a heat resistant and insulating fire member of the level higher than that of said cooling metal base for thermally shielding said low tritium-permeable layer from said plasma or corpuscular rays is formed on the low tritium-permeable layer. The similar processings are applied to the cooling metal base for forming the refrigerant passage for cooling a divertor disposed in the vacuum vessel and for neutralizing ionized corpuscles so as to exhaust them.
    Type: Grant
    Filed: May 15, 1990
    Date of Patent: January 26, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Yoshitaka Gotoh, Shigeru Kikuchi, Tetsuo Nakazawa, Tadahiko Miyoshi, Tetsuo Oyama, Yoshihiro Ozawa, Shin-ichi Itoh
  • Patent number: 4506041
    Abstract: A binder of this invention is a powder which comprises an intimate mixture of a copolymer of maleic anhydride with an olefinically unsaturated compound selected from the group consisting of an aliphatic .alpha.-olefin having 2 to 8 carbon atoms, styrene and methyl vinyl ether, 0.2 to 2.0 equivalents of a caustic alkali per carboxyl equivalent of said copolymer, and if desired, 30 to 500 parts by weight of an alkaline earth metal hydroxide per 100 parts of the total weight of said copolymer and said caustic alkali, and if desired, up to 300 parts by weight of additive per 100 parts of the total weight of said copolymer and said caustic alkali. A process for preparing a mold according to this invention comprises mixing said powdered binder with refractory particles and a small amount of water under agitation, and forming the resulting mixture into a shaped product, whereafter the shaped product is hardened by blowing CO.sub.2 gas therethrough.
    Type: Grant
    Filed: June 30, 1983
    Date of Patent: March 19, 1985
    Assignees: Hitachi, Ltd., Kinsei Kogyo Co., Ltd.
    Inventors: Takatoshi Tanigawa, Sakari Yaegashi, Tetsuo Nakazawa, Masahiko Hatazi, Tadao Nango
  • Patent number: 4278581
    Abstract: In a mold to be hardened by a CO.sub.2 gas, a mold binder material comprising a combination of polymers containing carboxyl groups, at least one of multi-valent metal oxides and multi-valent metal hydroxides, and resins of polyvinyl alcohol group, and at least one of sodium salt of gluconic acid and polyhydric alcohols or a mold binder material comprising a combination of polymers having carboxyl groups, at least one of multi-valent metal oxides and multi-valent metal hydroxides, and at least one of sodium salt of gluconic acid and polyhydric alcohols is provided.
    Type: Grant
    Filed: September 26, 1978
    Date of Patent: July 14, 1981
    Assignees: Hitachi, Ltd., Hitachi Metals, Ltd.
    Inventors: Tetsuo Nakazawa, Junji Sakai, Syogo Morimoto, Takatoshi Tanigawa, Ryoji Takahashi, Seiji Okazaki
  • Patent number: 4269256
    Abstract: A mold with an increased compression strength and a good collapsibility is prepared with a good efficiency by mixing refractory particles with a binder material comprising a caustic alkali-neutralized product of a copolymer containing a carboxyl group and calcium hydroxide, thereby preparing molding materials, filling the molding materials around a pattern, and blowing CO.sub.2 gas into the mold sand, thereby hardening the molding materials. Polyvinyl alcohol, calcium oxide, at least one hydroxide of zinc, aluminum, barium, magnesium, and iron, SBR latex, etc. can be added to the binder material, when desired.
    Type: Grant
    Filed: September 17, 1979
    Date of Patent: May 26, 1981
    Assignee: Hitachi, Ltd.
    Inventors: Tetsuo Nakazawa, Junji Sakai, Syogo Morimoto
  • Patent number: 4171297
    Abstract: Anti-crevice corrosion sealants for metals obtained by adding a mixture of zinc powder and dicyclohexylammonium nitrite powder bound by a vinyl silane coupling agent to a film-forming polystyrene dissolved in a solvent can restrain crevice corrosion occurring at crevices or jointed interior surfaces by filling the sealants into a fine crevice formed between the elements of metal machinery and tools or onto the jointed interior surface of the elements.
    Type: Grant
    Filed: September 8, 1977
    Date of Patent: October 16, 1979
    Assignee: Hitachi Ltd.
    Inventors: Nobuyoshi Hosaka, Tetsuo Nakazawa
  • Patent number: 3960798
    Abstract: A process for regulating the hardening speed of a self-hardening mold which comprises adding an alcohol as a hardening speed regulating agent when a mold is formed with molding sand prepared by adding a polyvinyl alcohol solution and a boron compound to refractory particles and then kneading the mixture. As the hardening speed regulating agent, polyhydric alcohol such as ethylene glycol, mannitol, sorbitol, glycerol, etc., and monohydric alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, etc., may be used.
    Type: Grant
    Filed: August 26, 1974
    Date of Patent: June 1, 1976
    Assignee: Hitachi, Ltd.
    Inventors: Tetsuo Nakazawa, Osamu Nishida