Hitachi, Ltd.

Hitachi Medical Corporation

Koichi Yokosawa

Daisuke Suzuki

Akihiko Kandori

Keiji Tsukada

Tsuyoshi Miyashita

Yasushi Goto

Ryuichi Shinomura

Akira Tsukamoto

Hideaki Nakane

Sadaki Nakano

Yukio Ito

Etsuji Yamamoto

Hideki Kohno

Hiroshi Kanda

Kazumichi Imai

Yutaka Sato

Toshio Kondo

Daizo Tokinaga

Shizuo Ishikawa

Masao Yabusaki

Shuzo Sano

Yukiko Ogura

Shinya Kuriki

In a hydrogen gas station where a great number of sensors are installed, in case hydrogen leakage occurs, sensors in the vicinity of the leakage location start to transmit a warning to an access point all at once. This causes channel capacity saturation and failure to transmit a warning to the access point. Nodes and the access point are connected to each other by an uplink channel and a downlink channel. The access point detects congested/uncongested status of the uplink channel by using a wireless transmitter module and notifies the nodes of the congested/uncongested status of the channel by means for transmitting onto the downlink channel. Meanwhile, each node controls its transmission operation, according to the hydrogen concentration level detected by its hydrogen sensor and the uplink channel congested/uncongested status notified from the access point. In this way, channel overflow due to access congestion in case of hydrogen leakage can be prevented.

Wireless terminal with gas leakage detection function, gas leakage detection system using the same, and gas leakage notification method

A gas detection system capable of suppressing the power consumption of the system using gas sensors required for heating for measurement at high accuracy, comprising a server and a plurality of gas sensors connected by way of wireless communication with the server, in which each of the gas sensors is provided with a heater, a controller for controlling the ON-OFF for the power supply to the heater and a comparator for comparing the detected gas concentration with a predetermined threshold value. In the gas detection system, electric power is not usually supplied to the heater in each of the gas sensors and the gas sensor measures the gas concentration at a low accuracy and always compares it with the threshold value. In a case where the gas concentration exceeds the threshold value in one of the gas sensors, it turns the heater of its own to ON thereby switching the measurement to that at high accuracy and turns the heater to OFF upon completing the measurement. At the same time, it informs the detection for the excess of threshold value to the server and the server lowers the threshold value of the gas sensors in the vicinity of the gas sensor that has informed the detection for the excess of threshold value to make the monitoring level severer.

Gas detection system

A magnetic field measurement system for canceling an external field is provided, in which plurality of sensing magnetometers () for measuring a magnetic field signal in a direction perpendicular to the center axis of a cylindrical magnetic shield () are arranged in two dimensions on a plane parallel to the center axis and a reference magnetometer () for measuring the external field parallel to the center axis as a reference signal is disposed on a plane perpendicular to the plane parallel to the center axis. The reference signal multiplied by a specified factor is subtracted from a difference between signals from the adjacent sensing magnetometers (). The magnetic field measurement system allows measurement of an extremely weak magnetic field by efficiently canceling the external field.

Magnetic field measurement system

An apparatus can detect a magnetic field with a high sensitivity using an ordinary-temperature pickup coil even when the pickup coil is arranged outside a cryostat. Specifically, the apparatus for measuring a magnetic field includes a pickup coil for detecting an external magnetic field, a SQUID electrically or magnetically connected to the pickup coil, a cryostat for holding the SQUID at low temperatures, and a driving device for driving the SQUID. The pickup coil is made of a normal-conducting material and is placed at an ordinary temperature outside the cryostat. By arranging outside the cryostat, the pickup coil can be brought close to a subject and can thereby detect a weak magnetic field in the subject with a high sensitivity.

Apparatus for measuring a magnetic field

A biomagnetic field measuring apparatus includes a plurality of SQUID magneto-meters for measuring a biomagnetic field generated from a living body, living-body signal measuring devices and for measuring and collecting living-body signals generated periodically, an operation processing device for operation processing the biomagnetic field signal and the living-body signal measured simultaneously as pairs in a plurality of directions, and a display unit for displaying a result of the operation processing. Change in time of excitation can be grasped in detail by using a small number of maps without presumption of a magnetic field source and display of many iso-magnetic field maps.

Biomagnetic field measuring apparatus

An apparatus for measuring bio-magnetic fields includes a plurality of magnetometers for detecting magnetic fields generated from a live body; a driving circuit for driving the magnetometers; a computer for collecting output signals of the driving circuit in the form of data representing at least one waveform of the magnetic fields generated from the live body and for performing an arithmetic processing on the data representing the waveform of magnetic fields, a display unit, and at least one signal processing circuit for processing output signals of the driving circuit. The computer further performs an arithmetic processing of first-order differentiation on the waveform of the magnetic fields in a z direction with respect to time in order to create an arrow map and a contour map. The apparatus can also detect mechanical movement which occurs as blood flows in organs and organs move.

Apparatus for measuring bio-magnetic fields

A gradiometer integrating pickup coils comprises pickup coils Xp, Xn magnetically connected to a SQUID through associated input coils , and pickup coils Yp, Yn magnetically connected to a SQUID through associated input coils , respectively. Two superconducting loops are connected in series to each of the SQUIDs, when viewed from Josephson junctions . The input coils form superconducting closed loops together with the pickup coils Xp, Xn, Yp, Yn associated therewith. The SQUIDs are respectively connected to form an -figured shape as a whole such that currents flow in two superconducting loops of each SQUID in opposite directions to each other, with respect to the application of a uniform field, in order to reduce environmental magnetic field noise.

Gradiometer integrating pickup coils and magnetic field measurement system

A magnetic field measuring apparatus has a magnetic field shielding apparatus including non-magnetic cylindrical members on which high-permeability sheets are located in a state of being partially overlapped with each other. The cylindrical members are located to surround an axis of a first direction concentrically and having a hollow portion, the cylindrical member located on an innermost-side having a first opening at one end of the first direction, a second opening at the other end of the first direction, and a third opening penetrating the cylindrical members in a direction perpendicular to the axis of the first direction. In addition, the magnetic field measuring apparatus has a living-body holder located in an inner-side space of the cylindrical member and a cryostat inserted into the third opening and maintaining SQUID magnetic-flux meters.

Magnetic field measurement apparatus

A high frequency continuous wave capable of achieving sufficient lateral resolution is produced by a wave transmitting device (,) to constitute a transmitted ultrasonic wave. A frequency of the continuous wave is alternated in a rectangular wave manner by a frequency modulator (,) so as to be frequency-modulated. An alternating time period of the frequency modulation is set to such time two times longer than such delay time which is defined from a time instant when a signal voltage is applied to a piezoelectric transducer element (,) up to another time instant when an ultrasonic wave originated from the piezoelectric transducer is reflected from a focal point,and then is reached to the piezoelectric transducer element. In a delay circuit (,), a delay equal to the delay time is applied to the transmitted ultrasonic wave so as to be used as a reference signal. A mixture signal produced by mixing the transmitted ultrasonic wave with the received ultrasonic wave is lock-in-detected (,), so that a reflection signal reflected from the checking object is selectively detected. As a result of increasing a total wave number of transmitted/received waves per unit time, since the continuous wave ultrasonic wave is irradiated onto the checking subject, for instance, in the case that living body tissue is imaged with high resolution at a cell level, S/N is improved.

Continuous wave transmission/reception type ultrasonic imaging device and ultrasonic probe

Pickup coils constructed by superconductors and a SQUID part are formed on a single substrate. The pickup coils are parallelly connected to two other superconductors (inductance of the SQUID ring) in a SQUID ring, which consists of two Josephson junctions and two superconductive lines. Each of the superconductors can be a superconductive line of one loop or a washer type coil. Each pickup coil occupies about one half of the area of the substrate and the SQUID and the pickup coils are symmetrical with respect to the center line of the substrate.

SQUID integrated with pickup coils

A needle-like ultrasonic probe includes an inner needle received in a hollow, tubular outer needle for rotation about an axis thereof. The inner needle has a pointed distal end, and a notch is formed in an outer peripheral surface of that portion of the inner needle which is located adjacent to the distal end thereof. At least one ultrasonic transducer, as well as an acoustic lens for converging an ultrasonic wave, produced by the ultrasonic transducer, onto a point near to the outer peripheral surface of the inner needle, is provided in the notch. A filler, having an outer surface conforming to the outer peripheral surface of the inner needle, is fitted in the notch. With this construction, after the inner needle is smoothly stuck into a living tissue, even if it is rotated and axially moved, the living tissue is less affected or damaged by the inner needle.

Needle-like ultrasonic probe for ultrasonic diagnosis apparatus, method

A pickup coil and a planar type SQUID are formed integrally on a single substrate to form a SQUID magnetometer. The SQUID is disposed on the surface of a projecting portion of the substrate and an insulating layer for spacing is laminated on the SQUID. The top, bottom and side surfaces of the assembly of the SQUID and insulating layer covering the same are all covered with a superconducting layer to form a magnetic shield for enclosing the SQUID. The magnetic shield is remote from the planar type pickup coil disposed on the remaining portion of the substrate by a distance which is equal to or greater than a length of one side of the size of the magnetic shield, thereby preventing magnetic flux distortion due to the presence of the magnetic shield from disturbing coil balance of the pickup coil.

Integrated-type SQUID magnetometer having a magnetic shield, and a

An RF magnetic flux measuring circuit uses a SQUID fluxmeter of which the input and output characteristics establish a periodic function, and in which a pick-up coil for picking up desired RF magnetic flux and an input coil of the SQUID fluxmeter are connected to form a closed loop which is a superconducting loop for transferring the magnetic flux to the SQUID. There is also provided an inductance adjusting device which adjusts the inductance of the superconducting loop to limit the magnetic flux that crosses the SQUID fluxmeter within a range of a single-valued function in said input and output characteristics.

Superconductor type radio frequency with adjustable inductance magnetic

The degree of agglutination is measured in a magnetic manner instead of optical manner. Microparticles are composed of a magnetic material and the agglutinated condition is measured using a magnetometer. The sizes and distribution of agglutinated materials formed by the antigen-antibody coupling reaction can be correctly measured without affected by light-scattering materials such as proteins or blood cells contained in the specimen, or by absorbant such as pigment, or by fluorescent material. Therefore, the concentration of antigen is measured maintaining high precision.

Particle agglutination immunoassay apparatus

In a signal detecting circuit of, for example, an NMR apparatus, a signal transmission path transmits an AC magnetic flux signal to be superposed on a DC magnetic field whose strength does not change with time during a period of signal detection. The signal transmission path comprises a superconducting closed loop including a receiving coil receiving the AC magnetic flux signal, an input coil applying the received AC magnetic flux signal as an input to a flux meter, and a variable resistor replacing part of the superconducting closed loop and having its resistance value changed in relation to a change in the strength of the DC magnetic field.

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Kodaira, Japan

Koichi Yokosawa