Patents Assigned to Tohoku Electric Power Company, Incorporated
-
Patent number: 6137391Abstract: A flux-controlled variable transformer can control voltage at a high speed without using any voltage adjusting tap. The transformer has a first and second magnetic circuits. The first magnetic circuit is composed of a first and second U-cut cores (13 and 11) which contact at their cut ends with each other in the state either of the two cores has been turned by 90.degree. in a twisting direction relative to the other. The primary winding (14) is wound in common around the second magnetic circuit and the first U-cut core (13) of the first magnetic circuit, the secondary winding (17) is wound around the second magnetic circuit and a control winding (12) is wound on the second U-cut core (11) of the first magnetic circuit. The magnetic flux linking the primary and secondary windings (14 and 17) can be controlled by change of the magnetic resistance in the first magnetic circuit with the primary winding (14) by changing a value of exciting current flowing in the control winding (12).Type: GrantFiled: March 11, 1999Date of Patent: October 24, 2000Assignee: Tohoku Electric Power Company, IncorporatedInventors: Koichi Mitamura, Mitsuru Maeda, Masaaki Sakamoto
-
Patent number: 5776862Abstract: The hole density of an oxide superconductor having holes as carriers is higher than the hole density to bring the highest value of the superconductivity critical temperature Tc thereof, and it can be made higher than the optimal density to bring the highest Tc value by treating the oxide superconductor with heat in an oxidizing gas atmosphere, or by replacing positive ions constituting the oxide superconductor except for copper with ions of a low valence number. Accordingly, it is possible to substantially reduce the rate of decrease of the critical current density owing to an applied magnetic field when the magnetic field is applied parallel to the crystal c axis, and to allow a current conductor produced by using the oxide superconductor to have high critical current density.Type: GrantFiled: July 22, 1996Date of Patent: July 7, 1998Assignees: Mitsubishi Denki Kabushiki Kaisha, Tohoku Electric Power Company, Incorporated, Toshiba Corporation, International Superconductivity Technology CenterInventors: Ryo Usami, Kazuyuki Isawa, Hiroshi Kubota, Roman Puzniak, Hisao Yamauchi, Shoji Tanaka
-
Patent number: 5639645Abstract: An isolated gene encoding .DELTA.9 desaturase of cyanobacteria, an expression vector containing the same, a transformant transformed therewith and a recombinant .DELTA.9 desaturase are provided, wherein said gene is useful for improving the composition of fatty acids of animals, plants and microorganisms by transformation and for producing animals, plants or microorganisms which tolerate low temperature.Type: GrantFiled: September 20, 1994Date of Patent: June 17, 1997Assignees: Mitsubishi Corporation, Mitsubishi Chemical Corporation, Tohoku Electric Power Company, IncorporatedInventor: Norio Murata
-
Patent number: 5407908Abstract: A method for manufacturing a Pb-based Cu oxide superconductor. The method includes the steps of mixing powders of a raw material containing at least Pb, Sr, Ce, M, where M is at least one element selected from the group consisting of Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, and Cu in a proportion to have the composition of the formula (I),Pb.sub.a (M.sub.1-x-y Ce.sub.x Sr.sub.y).sub.4 Cu.sub.3-a O.sub.z(I)where M is at least one element selected from the group consisting of Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, and a, x, y, and z denote the numbers which satisfy 0.3.ltoreq.a.ltoreq.0.7, 0<x.ltoreq.0.25, 0.3.ltoreq.y<0.5, 8.5.ltoreq.z.ltoreq.9.5, respectively, forming the mixed powder into a shaped body, and firing the shaped body at a temperature of 900.degree. to 1150.degree. C. in an oxidizing atmosphere.Type: GrantFiled: July 13, 1993Date of Patent: April 18, 1995Assignees: International Superconductivity Technology Center, Tohoku Electric Power Company, Incorporated, Central Research Institute of Electric Power Industry, The Furukawa Electric Co., Ltd.Inventors: Toshihiko Maeda, Kazuhiro Sakuyama, Shin-ichi Koriyama, Ataru Ichinose, Hisao Yamauchi, Shoji Tanaka
-
Patent number: 5252544Abstract: An oxide superconductor which has a composition expressed by the following general formula and whose crystal structure is 1222-phase structure.Pb.sub.a (M.sub.1-x-y Ce.sub.x Sr.sub.y).sub.4 Cu.sub.3-a O.sub.z (I)(where M represents at least one element selected from the group consisting of Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, and a, x, y, and z denote the numbers which satisfy 0.3.ltoreq.a.ltoreq.0.7, 0<x.ltoreq.0.25, 0.3.ltoreq.y<0.5, 8.5.ltoreq.z.ltoreq.9.5, respectively). A Pb-based Cu oxide superconductor manufacturing method comprising the steps of mixing powders of raw materials containing at least Pb, Sr, Ce, M (where M represents at least one element selected from the group consisting of Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu groups) and Cu in the proportion to have the composition shown in the general formula (I) above, optionally forming the mixed powder into a shape body, and firing the obtained powder mixture or the shape body in the temperature range of 900.degree.Type: GrantFiled: June 7, 1991Date of Patent: October 12, 1993Assignees: International Superconductivity Technology Center, Tohoku Electric Power Company, Incorporated, Kyocera Corporation, Central Research Institute of Electric Power Industry, The Furukawa Electric Co., Ltd.Inventors: Toshihiko Maeda, Kazuhiro Sakuyama, Shin-ichi Koriyama, Ataru Ichinose, Hisao Yamauchi, Shoji Tanaka
-
Patent number: 5021936Abstract: This invention relates to a PWM power converter for switching a plurality of bridge-connected semiconductor switching elements based on PWM signals. As the semiconductor switching elements, elements with a low ON voltage and small conduction loss, and elements with a small switching loss and capable of high-speed switching are combined to improve power conversion efficiency.Type: GrantFiled: June 28, 1990Date of Patent: June 4, 1991Assignees: Zaidan Hojin Handotai Kenkyu Sinkokai, Tohoku Electric Power Company, Incorporated, Tsuken Electric Ind. Co., Ltd.Inventors: Jun-ichi Nishizawa, Takashige Tamamushi, Koichi Mitamura, Hiroo Takahashi, Kiyoo Mitsui, Mitsuo Ikehara, Toyota Wako, Sinpei Maruyama
-
Patent number: 4815286Abstract: The present invention relates to an air flow check valve and a system incorporating a plurality thereof, having a function for rectifying the flow of air produced by compression and expansion of air in a closed air vessel which in turn is caused by the force of waves of the sea, as well as a function for regulating the pressure of rectified air flow, the air flow check valve having an air chamber, a liquid stored in the air chamber, a pipe extending into the air chamber and immersed in the liquid a predetermined depth, an inlet connected to the pipe and an outlet opening into the air chamber, wherein, when the air pressure at inlet becomes higher than the pressure at outlet by an amount corresponding to the depth of immersion of the pipe in the liquid, the air is discharged through the outlet and when the air pressure at the outlet higher than that at the inlet, the air forces the liquid in the air chamber into the pipe until the level of the liquid in the pipe rises at the immersion depth, so that the air flType: GrantFiled: November 2, 1987Date of Patent: March 28, 1989Assignee: Tohoku Electric Power Company, IncorporatedInventor: Kuniya Watanabe
-
Patent number: 4719551Abstract: The present invention provides an optically controlled power converting apparatus using light trigger/light quench electrostatic induction thyristors, as switching elements, which can execute the switching operations at a high speed being when they are supplied with light trigger pulses and light quench pulses. By supplying the light trigger pulses and light quench pulses at the timings corresponding to the pulse width modulation, the light trigger/light quench electrostatic induction thyristors can perform predetermined power converting operations.Type: GrantFiled: June 30, 1986Date of Patent: January 12, 1988Assignees: Zaidan Hojin Handotai Kenkyu Sinkokai, Tohoku Electric Power Company, IncorporatedInventors: Junichi Nishizawa, Takashige Tamamushi, Kimio Miura, Kiyoo Mitsui, Koichi Mitamura