Patents by Inventor Akihiko Hirayama

Akihiko Hirayama 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: 4958956
    Abstract: A resilient wave reducing structure which reduces waves propagating on liquid surface from propagating over the reducing structure and a method of constructing the wave reducing structure. The wave reducing structure of the present invention may be used to form a calm water surface region for harbors, for areas where construction work is being done or for areas where marine sports are to be performed etc. The resilient wave reducing structure includes at least one energy absorbing device having a resilient body constructed on a bottom of the liquid bounding the region where waves have to be reduced and filled with surrounding ambient liquid. This reduces the amplitude of waves passing over it by consuming the wave energy while it deforms according to the pressure distribution change caused by the waves and by radiating its kinetic energy into the liquid and the ground surrounding it.
    Type: Grant
    Filed: September 23, 1987
    Date of Patent: September 25, 1990
    Assignee: Shimizu Construction Co., Ltd.
    Inventors: Masahiro Tanaka, Takumi Ohyama, Akihiko Hirayama, Tetsushi Kiyokawa, Seiji Ichii, Yutaka Katsura, Tadashi Ono, Katsunori Shimizu
  • Patent number: 4851292
    Abstract: Disclosed herein are plate-like barium ferrite particles with a solid solution of zinc on the surface thereof, which have an average particle diameter of not less than 0.03 .mu.m and less than 0.1 .mu.m, a BET specific surface are of 55 to 80 m.sup.2 /g, a coercive force of 300 to 1,500 Oe and a magnetization of not less than 57 emu/g, preferably not less than 60 emu/g, in magnetic field of 10 KOe, and which are represented by the following formula (I):BaO.n[(Fe.sub.1-x-y Co.sub.x Ti.sub.y).sub.2 O.sub.3-x+y ] (I)wherein x and y are independently from 0.02 to 0.12 and n is from 4 to 11, the atomic ratio of Co to Fe(III) being from 0.02:1 to 0.13:1 and the molar ratio of Ti to Co being from more than 0 to not more than 0.8, and a process for producing the plate-like barium ferrite particles.
    Type: Grant
    Filed: January 29, 1987
    Date of Patent: July 25, 1989
    Assignee: Toda Kogyo Corp.
    Inventors: Norimichi Nagai, Akihiko Hirayama, Norio Sugita, Masao Kiyama, Toshio Takada, Katsunori Fujimoto, Yasutaka Ota
  • Patent number: 4806429
    Abstract: Disclosed herein are plate-like barium ferrite particles with a solid solution of zinc on the surface thereof, which have an average particle diameter of 0.05 to 0.3 .mu.m, a coercive force of 300 to 1,500 Oe and a magnetization of not less than 55 emu/g in magnetic field of 10 KOe, and which are represented by the following formula (I):BaO.multidot.n[(Fe.sub.1-2x Co.sub.x Ti.sub.x).sub.2 O.sub.3 ](I)wherein x is 0 to 0.1 and n is from 4 to 11, the molar ratio of Ti to Co being 1, and a process for producing the plate-like barium ferrite particles.
    Type: Grant
    Filed: January 29, 1987
    Date of Patent: February 21, 1989
    Assignee: Toda Kogyo Corporation
    Inventors: Norimichi Nagai, Akihiko Hirayama, Norio Sugita, Masao Kiyama, Toshio Takada, Katsunori Fujimoto, Yasutaka Ota
  • Patent number: 4781981
    Abstract: Disclosed herein are Ba-containing plate-like magnetoplumbite type ferrite particles for magnetic recording containing ions of one metal (II) selected from Ni and Zn and ions of one metal (IV) selected from Ti, Sn and Zr, and having zinc incorporated as a solid solution close to the particle surface and the change of coercive force of said particles at a temperature of -20.degree. to 120.degree. C. in the range of -0.5 to +0.5 Oe/.degree.C., and a process for producing the same.
    Type: Grant
    Filed: December 7, 1987
    Date of Patent: November 1, 1988
    Assignee: Toda Kogyo Corp.
    Inventors: Tsutomu Katamoto, Norimichi Nagai, Yasutaka Ota, Katsunori Fujimoto, Akihiko Hirayama, Masao Kiyama