Hitachi, Ltd.

Hitachi-lg Data Storage, Inc.

Toshio Saitoh

Noriyoshi Takahashi

Masayuki Shibata

Tadasi Sonobe

Naoki Maki

Teruhiro Takizawa

Takashi Kobayashi

Motoyuki Suzuki

Masaki Sato

Ken Yoshioka

Takashi Naganawa

Masatoshi Watanabe

Hideshi Fukumoto

Shigeki Yamazaki

Yuuji Yoshitomi

Fumio Suzuki

Jinya Ikeda

Toshio Shoji

Shota Iwakura

Tatsuo Seki

Masaki Satoh

Shizuo Tsujimoto

In a three-wavelength-compliant optical disk apparatus, the present invention enables to shorten time required for starting the apparatus such as discrimination of an optical disk and adjustment of a beam-expander. At the time of starting the apparatus, the operation of a tray driver which pulls a loaded optical disk within the apparatus is conducted in parallel with the operation of a beam-expander driver which allows a movable lens of the beam-expander to move to a predetermined position in accordance with the kind of optical disk. Further, at the time of discriminating the disk, the number of times an optical disk of a specific kind has continuously been loaded into the apparatus to date is stored in a memory, and a sequence of discriminating the kind of optical disk that is newly discriminated is switched by referring to the history information.

Optical disk apparatus and starting method thereof

In a focus controlling method of a laser beam for an optical disk, achieving a stable focus drawing-in, lowering ill influences due to stray lights, detecting an electric signal, which is obtainable upon basis of a reflection light from the optical disk loaded, in advance, while executing a focus sweep operation of gradually approaching the laser to a recoding surface of the optical disk, at an unnecessary light detection gain being higher than a gain of normal operation, thereby counting a number of signals generated due to unnecessary lights; and thereafter, detecting the electric signal, which is obtainable upon basis of the reflection light from the optical disk loaded, and thereby conducting a focus drawing-in, by considering an electric signal, which is generated just after a number detected thereof reaches to the counted number of signals generated due to the unnecessary lights, to be a signal reflected from the recording surface of the optical disk loaded.

Laser focus controlling method on an optical disk and an optical disk apparatus with using thereof

A superconducting magnet abnormality detection and protection apparatus is for early and surely detecting abnormality in superconducting coils mounted on a vehicle and protecting the superconducting coils. Magnetic flux detecting devices are mounted inside an outer vessel, which is a vacuum container of a superconducting magnet, so as to be opposite to the superconducting coil. Voltages induced in the magnetic flux detecting devices are detected. Voltage signals are led to a decision device. By monitoring the change of the voltage signals with time in a comparing judgment device, it is determined whether there is an abnormality. If there is an abnormality, an alarm indicator informs of an abnormal state, and a protection device takes protection measures such as interruption of the current of the superconducting magnet. Owing to such configuration, heat does not penetrate from the outside into the superconducting coil via instrumentation lead wires of the magnetic flux detecting devices. Magnitudes of vibration and displacement of the superconducting coil can be detected without contacting the superconducting coil. By always monitoring these signals, it becomes possible to early detect an abnormality in the superconducting coil and protect it.

Superconducting magnet abnormality detection and protection apparatus

A levitation system of a magnetically levitated train is provided wherein superconducting magnets are installed in a car body, and the first layer and the second layer of levitation coils are so arranged as to be in a shifted location relative to each other in the moving direction of the train. By making the levitation coils two layers and by arranging the two layers in the shifted location relative to each other in the moving direction, amplitude of higher harmonic waves is reduced to a very small level, substantially to zero.

Levitation system of a magnetically levitated train

Disclosed is a bar or conductor constituted by a plurality of strands disposed in a slot and extending outward from the opposite ends of the slot with each of the strands being substantially bisymmetrically vertically slanted so as to be transposed in the vicinity of a longitudinally central portion of the slot-inside bar portion. Each of the strands being transposed such that the respective strand arrangements at the opposite ends of the slot-outside bar end portions are reversed with respect to each other, with the total number of transposed portions of all the strands is less than three times the number of the strands.

Transpositioned multi-strand conductor for electric rotary machine

A method of relieving residual stress in a metal pipe comprises the steps of applying, by using a pressure medium, a low pressure to an interior of the metal pipe placed in dies, and applying, while preventing the buckling, an axial compression load to the pipe so as to effect a uniform plastic deformation of the entire metal pipe while maintaining the desired shape of the pipe, thereby relieving the residual stress in the metal pipe.

Method of relieving residual stress in metal pipe

An apparatus for connecting conductor strands with transposition in an electrical rotary machine is disclosed to include a plurality of electrically conductive connector rods respectively connected to ends of the individual strands of each conductor, and a plurality of electrically conductive plates arrayed in the axial direction of the conductive connector rods and adapted to mutually connect respective pairs of strands of the multiple strand conductors through the corresponding conductive rods while electrically insulating one strand pair from other strand pairs.

Apparatus for connecting conductor strands with transposition in

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Hitachi, Japan

Toshio Saitoh