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1. 发明专利

CA1283161C TRANSFORMER PROTECTION SYSTEM 未知
公开(公告)号：CA1283161C
公开(公告)日：1991-04-16
申请号：CA520283
申请日：1986-10-10
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： OURA YOSHIFUMI , MATSUZAWA KUNIO , YOSHIDA KAZUYOSHI , INAGAKI KEIZO , KUDO HIROYUKI , SANO YOSHIHIRO
IPC分类号： H02H3/44 , H02H7/04
摘要： In a transformer protection system, data of voltages and currents detected at individual terminals of a transformer connected to an electric power system are supplied to a computer. The computer computes driving point admittances or shunt admittances of the transformer on the basis of the voltage and current data and predetermined transfer admittances of the transformer and decides that an internal fault has occurred in the transformer when the values of the driving point admittances or shunt admittances deviate from pre-set reference values, thereby disconnecting the transformer from the electric power system.

2. 发明专利

DE3680282D1 未知
公开(公告)号：DE3680282D1
公开(公告)日：1991-08-22
申请号：DE3680282
申请日：1986-10-13
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： OURA YOSHIFUMI , MATSUZAWA KUNIO , YOSHIDA KAZUYOSHI , INAGAKI KEIZO , KUDO HIROYUKI , SANO YOSHIHIRO
IPC分类号： H02H3/44 , H02H7/04
摘要： In a transformer protection system, data of voltages and currents detected at individual terminals of a transformer (1) connected to an electric power system are supplied to a computer (5, 6. 7, 8, 9). The computer computes driving point admittances or shunt admittances of the transformer on the basis of the voltage and current data and predetermined transfer admittances of the transformer and decides that an internal fault has occurred in the transformer when the values of the driving point admittances or shunt admittances deviate from pre-set reference values, thereby disconnecting the transformer from the electric power system.

3. 发明专利

JP2000123343A MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING AND REPRODUCING DEVICE USING THE SAME 失效
公开(公告)号：JP2000123343A
公开(公告)日：2000-04-28
申请号：JP28907098
申请日：1998-10-12
申请人： HITACHI LTD
发明人： IGARASHI KAZUSUKATSU , AKAGI FUMIKO , YOSHIDA KAZUYOSHI
IPC分类号： G11B5/66 , G11B5/64 , G11B5/65 , G11B5/73 , G11B5/738 , H01F10/26
摘要： PROBLEM TO BE SOLVED: To reduce the effect of thermal fluctuation due to micronization of magnetic particles without increasing a magnetic field necessary for a recording head by making the adjacent magnetic particles adjacent to each other through a nonmagnetic region, specifying the thickness of the nonmagnetic region and optimizing the gap. SOLUTION: A magnetic layer comprising an aggregate of magnetic particles is formed. One magnetic particle is adjacent to another magnetic particle through a nonmagnetic region. The thickness of the nonmagnetic region is 0.5 to =8 gigabit/in2 by combination with a magnetoresistance effect type magnetic head having high reproduction sensitivity.

4. 发明专利

JPH11306535A MAGNETIC RECORDING MEDIUM AND MAGNETIC MEMORY REPRODUCING DEVICE 失效
公开(公告)号：JPH11306535A
公开(公告)日：1999-11-05
申请号：JP11461898
申请日：1998-04-24
申请人： HITACHI LTD
发明人： AKAGI FUMIKO , YOSHIDA KAZUYOSHI , INABA NOBUYUKI
IPC分类号： G11B5/66 , G11B5/39 , G11B5/65
摘要： PROBLEM TO BE SOLVED: To suppress the influences of thermal fluctuation by determining the magnetic anisotropic magnetic field and coercive force of a magnetic layer and the magnetic anisotropy const. of a magnetic recording medium to satisfy a specified relation. SOLUTION: The relation between the magnetic anisotropic magnetic field Hk and coercive force Hc of the magnetic layer of a magnetic recording medium are determined to less than Hc/Hk =2×10 J/m . As for the magnetic recording layer having the characteristics, CoPt or a material prepared by adding N or B or a compd. of N and B to four kinds of alloys of CoSm, CoY, CoCe, COPr is used. In this structure, the coercive force also increases and therefore, a bicrystal structure is used to decrease the coercive force. Thus, the gaps are produced among particles in a Cr base layer and the distance among the crystal grain groups of grains having a bicrystal structure can be increased.

5. 发明专利

JPH11296833A PERPENDICULAR MAGNETIC RECORDING MEDIUM AND MAGNETIC MEMORY DEVICE 失效
公开(公告)号：JPH11296833A
公开(公告)日：1999-10-29
申请号：JP9333498
申请日：1998-04-06
申请人： HITACHI LTD
发明人： FUTAMOTO MASAAKI , HIRAYAMA YOSHIYUKI , ITO KIYONARI , YOSHIDA KAZUYOSHI , HONDA YUKIO
IPC分类号： G11B5/66 , G11B5/02 , G11B5/64 , G11B5/65 , G11B5/738
摘要： PROBLEM TO BE SOLVED: To provide a perpendicular magnetic recording medium improved to be suitable for a high-density magnetic recording. SOLUTION: A ground surface layer is formed of a two-layered structure composed of a first ground surface layer 12 consisting of a material having a hexagonal close- packed structure or amorphous structure and a second ground surface layer 13 consisting of material which has the hexagonal close-packed structure, has a preferential growth bearing at [0001] and can be matched and grown to the perpendicularly magnetized film to be formed thereon. The perpendicularly magnetized film consisting of a Co alloy polycrystalline film is formed of a two-layered structure consisting of the lower layer perpendicularly magnetized film 14 and the upper layer perpendicularly magnetized film 15. The upper layer perpendicularly magnetized film is made lower in the total addition element concn. of a nonmagnetic element than the lower layer perpendicularly magnetized film. In addition, the saturation magnetization (Ms) and magnetic anisotropy energy (Ku) are made larger. The total thickness of the perpendicularly magnetized films is made to be from 5 to 70 nm. The average grain size of the crystal grains measured on the surface side of the upper layer perpendicularly magnetized film is specified to be from 5 to 15 nm.

6. 发明专利

JPH11203608A RECORDING EQUALIZER AND MAGNETIC RECORDING AND REPRODUCING DEVICE USING THE SAME 失效
公开(公告)号：JPH11203608A
公开(公告)日：1999-07-30
申请号：JP449598
申请日：1998-01-13
申请人： HITACHI LTD
发明人： IGARASHI KAZUSUKATSU , MARUYAMA YOJI , YOSHIDA KAZUYOSHI
IPC分类号： G11B5/09
摘要： PROBLEM TO BE SOLVED: To simplify a recording correcting system and to allow it to have high accuracy by controlling the pattern of a recording current as desired at the time of recording magnetization information. SOLUTION: A current from a constant current power source 22 to be driven with a high voltage power source 24 is directed to a recording head via a switching circuit 21. The switching circuit 21 inverts the polarity of the current according to outputs A(n) from a data butter. Outputs i(n) from a current value calculating circuit are inputted to a current bypassing circuit 23 to make a prescribed current so as to flow through the circuit 21 by branching one part of the current from the constant current circuit 22. Here, the circuit 23 digitally control a reference potential by the outputs i(n) from the current value calculating circuit while using a current mirroring circuit. Then, the far the recording head is separated from the rotary shaft, the faster the rising time of the recording current is made by changing the voltage of the power source driving the constant current power source 22 with a digital circuit while using the control signal of an actuator driving the recording head.

7. 发明专利

JPH10334440A MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING AND REPRODUCING DEVICE 失效
公开(公告)号：JPH10334440A
公开(公告)日：1998-12-18
申请号：JP14483597
申请日：1997-06-03
申请人： HITACHI LTD
发明人： FUTAMOTO MASAAKI , INABA NOBUYUKI , HIRAYAMA YOSHIYUKI , HONDA YUKIO , YOSHIDA KAZUYOSHI , ITOU KIYONARI
IPC分类号： G11B5/66 , G11B5/64 , G11B5/65 , G11B5/738
摘要： PROBLEM TO BE SOLVED: To make it possible to decrease the noises of a perpendicular magnetic recording medium and to increase its density by providing this medium with a first perpendicularly magnetized film and a multilayered structure a second perpendicularly magnetized film of or an amorphous structure formed thereon, specifying the sum of the thicknesses thereof to a prescribed value or below and making the thickness of the second perpendicularly magnetized film smaller than the thickness of the first perpendicularly magnetized film. SOLUTION: The surface of the first perpendicularly magnetized film 13 is provided with the second perpendicularly magnetized film 14 of the multilayered film type of the intra-surface magnetic coupling force larger than that of the first perpendicularly magnetized film or the amorphous perpendicularly magnetized film contg. a rear earth element. As a result, the magnetic fluctuations of the surface of the first perpendicularly magnetized film 13 are decreased. Since the second perpendicularly magnetized film 14 has the larger intra-surface magnetic coupling force, the surface is free from the micromagnetic fluctuations. The thickness of the second perpendicularly magnetized film 14 is made smaller than that of the first film and is set at =5 Gb/in , by which the magnetization inversion volume is made smaller and the deterioration of the recording magnetization at the thermal fluctuation is prevented.

8. 发明专利

JPH10334403A RECORDING EQUALIZER AND MAGNETIC RECORDING/REPRODUCING DEVICE USING THE SAME 失效
公开(公告)号：JPH10334403A
公开(公告)日：1998-12-18
申请号：JP14182697
申请日：1997-05-30
申请人： HITACHI LTD
发明人： IGARASHI KAZUSUKATSU , MARUYAMA YOJI , YOSHIDA KAZUYOSHI , SAITO IKUO
IPC分类号： G11B5/00 , G11B5/035 , G11B5/09 , G11B20/10 , G11B20/14
摘要： PROBLEM TO BE SOLVED: To reduce the disturbance of a magnetization inverting position so as to realize high density recording by increasing the accuracy of recording correction. SOLUTION: When the recording correction amount A of a first dibit transfer A (3) for recording being away from a previous transfer by at least 3 bits or more and from a succeeding transfer by at least 2 bits or more is set as A, the recording correction amount of a second transfer A (4) is set as B and the recording correction amount of an independent bit A (0) for recording being away from a previous transfer by at least 3 bits or more and from a succeeding transfer by at least 2 bits or more is set as C, a value (A-C) is set in the range of -5% to -60% of a value (B-C) and C is selected such that A takes a positive value.

9. 发明专利

JPH10326409A MAGNETIC RECORDING MEDIUM 失效
公开(公告)号：JPH10326409A
公开(公告)日：1998-12-08
申请号：JP12194698
申请日：1998-05-01
申请人： HITACHI LTD
发明人： YOSHIDA KAZUYOSHI , SHIROISHI YOSHIHIRO , SAITO MAKOTO , TSUMITA NORIKAZU , YAMASHITA TAKEO , SUZUKI HIROYUKI , KITAZAKI YASUSHI , OURA MASAKI
IPC分类号： G11B5/66 , G11B5/64 , G11B5/65 , G11B5/738 , H01F10/16 , H01F41/18
摘要： PROBLEM TO BE SOLVED: To clearly show magnetic characteristic to be provided in a magnetic thin film for reducing noise and to make it possible to obtain a high S/N characteristic, by making the magnetic thin film to be a magnetic recording layer a magnetic thin film that of which rotary hysteresis loss integration value obtained by measuring with a magnetic torque meter exist within a specified range. SOLUTION: When magnetic anisotropy of a magnetic thin film specimen is measured by the magnetic torque meter, the intensity of the magnetic field is adjusted so that hysteresis appears in a torque curve when the magnetic thin film specimen is rotated in the reverse direction after the magnetic thin film specimen is applied with a magnetic field to be rotated by 360 deg. in the one direction, and the area surrounded by two pieces of torque curves, that is, a rotary hysteresis loss Wr is obtained. The rotary hysteresis loss Wr is divided by saturated magnetic flux density Is. and is integrated by the reciprocal of the size H of the magnetic field, and the rotary hysteresis loss integration value RH is obtained. The magnetic thin film with the range 0.4-1.3 of the rotary hysteresis loss integration value RH is made the magnetic recording layer. Thus, a medium noise is reduced remarkably, and the magnetic recording layer excellent in S/N characteristic and high in reliability is obtained.

10. 发明专利

JPH08124122A MAGNETORESISTIVE REPRODUCING HEAD AND MAGNETIC RECORDING/REPRODUCING DEVICE 失效
公开(公告)号：JPH08124122A
公开(公告)日：1996-05-17
申请号：JP26000894
申请日：1994-10-25
申请人： HITACHI LTD
发明人： FUJIMOTO KAZUHISA , KAMISAKA YASUTARO , SUZUKI KO , AIHARA MAKOTO , YOSHIDA KAZUYOSHI , FUKUI HIROSHI
IPC分类号： G11B5/39
摘要： PURPOSE: To increase the reproducing output of a magnetoresistive reproducing head. CONSTITUTION: A lower shielding film (NiFe film) 10 of 2μm thickness, a magnetic gap forming insulating film (Al2 O3 film) 20 of 0.2μm thickness, a soft magnetic film (NiFeNb film) 30 of 20nm thickness a nonmagnetic electrically conductive film (Ta film) 40 of 15nm thickness and a magnetoresistive film (NiFe film) 50 of 20nm thickness are successively laminated on a substrate 5 and patterning is carried out so as to decide the height of the magneto- resistive film 50. An org. resist film is then laminated and patterning is carried out in the desired shape.

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