Denso Corporation

Nippon Soken, Inc.

Toshiba Medical Systems Corporation

Fps Inc.

Other

Kabushiki Kaisha Toshiba

Canon Medical Systems Corporation

Advics Co., Ltd.

Masashi Hori

Kiyoshi Kimura

Motohiro Miura

Shigeru Yoshiyama

Haruki Matsuzaki

Tomoyuki Kashiwagi

Masaaki Shinojima

Sho Kawajiri

Yasuhiko Mukai

Toshihiro Miyake

Taku Itoh

Taku Iida

Takashi Kamiya

Yoshio Hironaka

Hideki Kabune

Hironori Asa

Kouichi Nakamura

Motohisa Yokoi

Hiroki Kamiya

Yasushi Matsumura

Kuniyuki Kobayashi

Masahiro Iwata

Masashi Hiramatsu

Shigeru Kamio

Koichi Nakamura

Yoshimori Kassai

Yasuhiro Nakai

Hidekazu Tanaka

Takeshi B Nishimura

Hideo Tomomatsu

Yuzo Imoto

Akira Hoshino

Nobuhiko Uryu

Takahisa Yokoyama

Akihiko Takenaka

Hideki Miyata

Kazuyuki Soejima

Takahisa Suzuki

Takayuki Takeshita

Akio Mori

Hitoshi Tanaka

Haruki Nakamura

Yoshichika Yamada

Hiroshi Kusahara

Mitsuo Takagi

Yutaka Machii

Masayuki Ishiwa

Kenji Iizuka

Fumihito Meguro

Naoki Imamura

Hiroyuki Shintani

Toshiiku Miyazaki

Takahiro Kobayashi

Masamichi Watanabe

Kazuhiro Hamaya

Hiromi Saotome

Tomomi Nakatsuka

Ken Kudou

Hiromi Sotome

Tohru Nakabayashi

Shinji Takeuchi

Yasuo Enokido

Kunihiko Ohbayashi

Hiromichi Yamazaki

According to one embodiment, a magnetic resonance imaging apparatus includes an amplifier, a gradient coil, and adjusting circuitry. The amplifier includes pulse width modulation circuitry modulating a pulse width of a driving signal, which is input to switching elements, in accordance with an input of a control signal corresponding to a waveform of a gradient magnetic field. The gradient coil generates the gradient magnetic field by an electric current supplied in accordance with an output voltage which is output from the amplifier. The adjusting circuitry executes adjustment of a gain of the amplifier, which is included in the control signal, or adjustment of the pulse width of the driving signal, in accordance with a dead time included in a switching cycle of the switching elements.

Magnetic resonance imaging apparatus with enhanced image quality

According to one embodiment, a magnetic resonance imaging apparatus includes amplifiers, processing circuitry, and a power supplier. The amplifiers supplies power for each of a plurality of channels of gradient coils. The processing circuitry obtains, for each of the channels, a voltage gradient that represents a temporal change of a power supply voltage for supplying a current to the amplifiers. The power supplier supplies the power to an amplifier corresponding to a specific one of the channels on a priority basis in accordance with the voltage gradient.

Magnetic resonance imaging apparatus for supplying power to gradient coils

A magnetic resonance imaging apparatus according to a present embodiment includes a gradient magnetic field coil and a gradient magnetic field power supply. The gradient magnetic field coil applies gradient magnetic field to an object, the gradient magnetic field coil including a plurality of channels. The gradient magnetic field power supply calculates a required power for each channel, and distributes maximum power to a channel requiring higher power than the required power of other channels with priority to the other channels, the maximum power being a limit value of total power to be supplied to the channels as a whole.

Magnetic resonance imaging apparatus and gradient magnetic field power supply device

A control device of a magnetic resonance (MRI) imaging apparatus includes a condition setting unit and a judging unit. The condition setting unit sets an imaging sequence to be performed by the magnetic resonance imaging apparatus based on set conditions of the set imaging sequence. The judging unit then (a) calculates a value of electric current supplied to a gradient magnetic field coil of the MRI apparatus to perform that set imaging sequence based on the set conditions of the set imaging sequence, (b) calculates a value of voltage that would need to be applied to the gradient magnetic field coil based on a mutual inductance of the gradient magnetic field to cause electric current flowing to the gradient magnetic field coil to become equal to the value of the calculated electric current, and (c) judges whether the set imaging sequence is practicable or not based on the calculated value of voltage.

Magnetic resonance imaging apparatus and control device of a magnetic resonance imaging apparatus

A control section of a steering controller calculates a steer angle which is a turning angle of a first column shaft based on a first detection value detected by a steer angle sensor, and calculates a second shaft turning angle which is a turning angle of a second column shaft based on a second detection value detected by a second shaft rotation angle sensor. A steering torque detection value is calculated based on a third detection value detected by a torque sensor. An abnormality determination part determines abnormalities of the steering torque detection value based on the steer angle and the second shaft turning angle. Thereby, abnormalities of the steering torque detection value are detected without multiplexing the steering torque detection value. Further, if the steering torque detection value is multiplexed, an abnormal steering torque detection value can be specifically identified.

Steering controller

A cooling device for sub-MRI units of an embodiment includes a tank in which cooling water for cooling a heat generating unit that an MRI apparatus has is stored, a pump which circulates the cooling water stored in the tank through a circulation path starting from the tank and traveling around the heat generating unit, a heat exchanger which cools the cooling water, and a controller which decides that a water leakage has occurred on the circulation path when a decreasing rate of the cooling water in the tank is greater than a given reference value.

Cooling device for sub-MRI units and MRI apparatus

A magnetic resonance imaging device according to an embodiment includes a gradient amplifier, a battery, a detector, and a battery controller. The gradient amplifier supplies electric power to the gradient coil. The battery is charged with electric power that is supplied from the power supply. The detector detects a high power output request on the gradient amplifier. The battery controller controls to supply electric power charged in the battery in addition to electric power supplied from the power supply to the gradient amplifier when the high power output request is detected.

Magnetic resonance imaging device

An MRI apparatus includes a charge/discharge controlling unit, a judging unit and a condition restricting unit. The charge/discharge controlling unit includes a charge/discharge element, receives electric power, and charges the charge/discharge element by using the received electric power. The charge/discharge controlling unit also supplies a gradient magnetic field coil with electric power discharged from the charge/discharge element at a time of performance of magnetic resonance imaging. The judging unit judges whether capacitance of the charge/discharge element falls below a threshold value or not. The condition restricting unit restricts electric power amount supplied to the gradient magnetic field coil by restricting conditions of an imaging sequence, when the capacitance of the charge/discharge element falls below the threshold value.

Magnetic resonance imaging apparatus and magnetic resonance imaging method

A hybrid speaker is provided. The hybrid speaker can include first magnets, second magnets, a yoke that accommodates the first and second magnets, a diaphragm, voice coils fixed at one face of the diaphragm, a frame, and a plate spring resiliently supporting the yoke at the frame. The first magnets can be arranged at predetermined intervals such that south poles or north poles thereof are oriented to the same side. The second magnets can have smaller volumes than the first magnets and be arranged singly or plurally between the first magnets their magnetic poles oriented the opposite those of the first magnets. The voice coils can be disposed so as to cross magnetic circuits between the first magnets and the yoke. The diaphragm can be fixed to the frame at periphery portions of the face at the side of the diaphragm at which the voice coils are fixed.

Hybrid speaker

A control device of a magnetic resonance imaging (MRI) apparatus includes a condition setting unit and a judging unit. The condition setting unit sets an imaging sequence to be performed by the MRI apparatus based on set conditions of the set imaging sequence. The judging unit then (a) calculates a value of electric current that would need to be supplied to a gradient magnetic field coil of the MRI apparatus to perform that set imaging sequence based on the set conditions of the set imaging sequence, (b) calculates a value of voltage that would need to be applied to the gradient magnetic field coil based on a mutual inductance of the gradient magnetic field to cause electric current flowing to the gradient magnetic field coil to equal to the value of the calculated electric current, and (c) judges whether the set imaging sequence is practicable or not based on the calculated value of voltage.

According to one embodiment, there is provided a magnetic resonance imaging apparatus in which a gradient field power supply apparatus supplies currents to gradient field coils corresponding to spatial coordinate axis directions to form gradient fields in a static field space which change along the respective spatial coordinate axis directions, the gradient field power supply apparatus includes a transformer configured to supply power supplied to a primary winding to a current output circuit via a plurality of secondary windings, with the number of phases of the primary windings being equal to or a multiple of the number of phases of the secondary windings, and the secondary windings of the respective phases of output channels corresponding to the respective spatial coordinate axis directions being wound around the primary windings of the respective phases.

Gradient field power supply and magnetic resonance imaging apparatus

A VGRS device checks whether assist control of an EPS device for assisting steering operation of a steering wheel is being stopped. If the assist control of the EPS device is being stopped, a speed increase ratio is determined so that the rotation angle of the output shaft is less than the rotation angle of the input shaft. A VGRS motor is controlled and driven based on a determined speed increase ratio. Thus, steering operation of the steering wheel can be controlled appropriately so that the steering operation of the steering wheel can be continued with relatively small torque. It is less likely that a driver will erroneously feel that the steering wheel is locked.

Steering control apparatus

A composite speaker is provided capable of obtaining larger sound output than that of a conventional flat panel speaker and flat speaker when input with an audio signal of the same strength. The composite speaker includes: one magnet or a plurality of magnets disposed at predetermined intervals to each other; a yoke for forming a magnetic circuit with a magnetic gap to the magnets; a voice coil disposed in a gap between the magnets and the yoke so as to interlink with the magnetic circuit; a diaphragm with the voice coil fixed to one face thereof; a frame that supports the diaphragm at peripheral edge portions of the diaphragm and houses the magnets and the yoke; a speaker base plate fixed to the frame at the side of the frame supporting the diaphragm or at the side of the frame opposite to the side supporting the diaphragm; and a phase rotation member configured by an elastic member provided between the speaker base plate and the yoke; wherein sound is generated from both the diaphragm and the speaker base plate.

Composite speaker

A flat acoustic transducer () includes a permanent magnet () and a magnetic member (), which are arranged adjacent to each other with a predetermined interval, a flat vibrating membrane (), provided facing the permanent magnet () and the magnetic member (), and at least one coil (), fixed to the vibrating membrane (). In the flat acoustic transducer (), an electrical signal is applied to the coil (), to obtain vibration force (F) on the vibrating membrane () by way of a magnetic flux &#x3a6; generated between a magnetic pole face () of the permanent magnet () and the magnetic member (), a step () is provided between the magnetic pole face () and the upper face () of the magnetic member (), while at least part of a winding () of the coil () at the time of no application of an electrical signal is arranged inside the step ().

Flat acoustic transducer and method for driving the same

In a steering control apparatus, a worm gear is configured to have a lead angle for a self-lock operation, by which a worm wheel is allowed to rotate by rotation of a worm but the worm is not allowed to rotate by rotation of the worm wheel. Thus, a lock mechanism need not be provided separately from a gear mechanism and the apparatus is reduced in entire size. A VGRS control part checks whether the worm gear has a self-lock failure, which disables the self-lock operation. If the worm gear has the self-lock failure, idling suppression processing is performed to suppress idling of a steering wheel. Thus, even when the self-lock failure arises, the steering wheel is suppressed from idling.

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Anjo, Japan

Masashi Hori