213results about "Magnetic measurements" patented technology

The application discloses a device and method for compensating magnetic field gradient of a segmented dDNP polarization system, which comprises a gradient monitoring module and a dynamic compensation module. The gradient monitoring module comprises a magnetic sensor combination, which comprises at least two magnetic sensors distributed along the transfer path direction of a sample, and the magnetic sensors are used for detecting a first gradient magnetic field corresponding to the transfer path of the sample. The dynamic compensation module comprises a segmented gradient coil, which is arranged along the transfer path of the sample to form multiple independent coil units. The current of each independent coil unit is independently adjusted according to the first gradient magnetic field, so that the segmented adjustment and overall homogenization of the magnetic field gradient of the transfer path are realized. The dynamic magnetic field gradient inside the polarizer is measured in real time by using the magnetic sensor combination, and the precise compensation of the gradient magnetic field is realized through the reverse compensation of the segmented gradient coil, so that the high polarization fidelity of the sample in the transfer process is ensured.

The present invention relates to an apparatus for detecting peripheral nerve stimulation (PNS). The apparatus includes an input unit, at least one sensor, a processing unit, and an output unit. The input unit is configured to provide the processing unit with information regarding individual scans of a scan sequence of a magnetic resonance imaging (MRI) unit used to perform medical imaging of a patient. The at least one sensor is configured to acquire sensor data of the patient undergoing medical imaging. The processing unit is configured to determine the presence of peripheral nerve stimulation (PNS), the determination of the presence of PNS comprising information regarding the individual scans of the scan sequence and the patient's sensor data. The output unit is configured to output an indication that the presence of PNS has been determined.

The application belongs to the technical field of magnetic field navigation, and particularly relates to a three-axis magnetic sensor positioning and pose determination method and system based on a magnetic beacon. Step 1: the distribution of the magnetic field generated by the magnetic beacon at any position in space is expressed by a spherical harmonic function; Step 2: based on the position of the magnetic beacon, the relative position of the magnetic beacon and the magnetic sensor is confirmed; Step 3: based on the relative position of Step 2, a positioning and pose determination equation of the magnetic sensor is established; Step 4: the equation of Step 3 is solved by using a particle swarm algorithm to obtain spherical coordinates; Step 5: the spherical coordinates solved in Step 4 are converted into Cartesian coordinates, and the positioning and pose determination of the magnetic sensor are completed. The spatial coordinates and the attitude of the magnetic sensor are accurately calculated through the magnetic field generated by the magnetic beacon at the magnetic sensor to be measured, thereby supporting the technical development in the related field.

The application relates to the technical field of magnetic resonance imaging, in particular to a magnetic resonance multi-channel coil automatic shimming method, which aims to solve the problem of how to quickly, stably and flexibly realize main magnetic field distortion compensation. The method comprises the following steps: constructing a multi-channel coil according to a target field of a non-uniform main magnetic field, wherein the multi-channel coil comprises a plurality of coil units; acquiring a free induction decay signal of the non-uniform main magnetic field; inputting the free induction decay signal into a pre-trained Transformer automatic shimming regulation model after the free induction decay signal is converted into a frequency domain, so as to obtain a multi-channel coil compensation current; and the Transformer automatic shimming regulation model comprises a signal serialization unit, a global feature extraction encoder and a parallel regression prediction network which are sequentially cascaded. The magnetic resonance multi-channel coil automatic shimming method provided by the application forms a complete shimming solution and can meet the high-performance requirement of magnetic field fast compensation.

The present application relates to a kind of Hall thruster total impulse margin on-orbit prediction method and prediction system, according to Hall drift current density and the radial component of magnetic field given excitation current under thruster fixed design parameter, utilize on-orbit thrust calculation model, calculate the on-orbit thrust of Hall thruster in each time in first period, obtain several on-orbit thrust values;The time-averaged thrust value of first period is calculated;According to the capacity of gas tank and the first density of first time, the first calibration value of propellant margin in gas tank at first time is calculated, the second calibration value of second time is calculated, the time-averaged flow of first period is calculated;Finally, according to the time-averaged thrust value, the second calibration value and the time-averaged flow, the total impulse margin prediction value of second time is calculated.The above-mentioned method can predict the prediction value of total impulse margin of Hall thruster at target time, provide reference standard for the evaluation of remaining service life of Hall thruster, and be favorable to the further development and application of Hall thruster.

In the virtual brain twin framework, the propagation network is segmented into nodes that represent grey matter areas in the brain. Each node has its own time-resolved dynamics, which are influenced by both local and global connections with other nodes in the network. The distance-based approach is used to allocate weights rendering short range connectivity, while long-range tract-based connectivity is allocated using a weight rendering method. Differentiated conduction velocities are also assigned to long-range and short-range connectivities, which allows for more accurate simulation of neural activity and its propagation within the brain.

The application provides a full-bridge magnetoresistance sensor and an electronic device. The circuit structure of the full-bridge magnetoresistance sensor is a full-bridge circuit structure, and the long axis directions of each sensing unit on adjacent bridge arms in the full-bridge circuit structure are parallel. The sensing unit comprises a flip function layer, a dielectric layer and a magnetoresistance thin film arranged from bottom to top. The flip function layers of the sensing units on two parallel bridge arms are connected to the same current input end, and the flip function layers of the sensing units on the other two parallel bridge arms are connected to the same ground end. By applying a single current to the current input end, the current flowing through the flip function layers of the adjacent bridge arms is opposite, so that the pinning direction of the anti-ferromagnetic layer of the sensing unit in which the heat generated by the flip function layer and the local magnetic field are reversed is opposite, and then the magnetization direction of the reference layer in the sensing unit on the adjacent bridge arm is opposite, so that a complete full-bridge structure is realized on a single chip, and the effect of flexibly setting or resetting the reference layer direction after production or during use can be achieved.

The invention relates to at least one method and at least one localization system for localizing a portable component (6, 13) of an imaging system (1), wherein the portable component (6, 13) is arranged on a patient (8) for an examination procedure, comprising: - Emitting at least one optical localization signal (210, 211, 212) in an imaging area (12) of the imaging modality (11) by at least one optical transmitting element (201, 202, 203), - Receiving the at least one emitted optical localization signal (210, 211, 212) by at least one optical receiving element (220, 221, 222) which is arranged on the portable component (6, 13), - Transmission of at least one received optical localization signal (210, 211, 212) via an optical transmission link (230 - 235) to an electronic evaluation unit (240) which is located outside an examination room (250), and - Localization of the portable component (6 ,13) based on the at least one received optical localization signal (210, 211, 212) by the electronic evaluation unit (240).

To provide a magnetoresistance effect element with a large MR ratio.SOLUTION: A magnetoresistance effect element comprises a first ferromagnetic layer, a second ferromagnetic layer, and a non-magnetic layer. The first ferromagnetic layer includes a first layer and a second layer. The first layer is arranged closer to the non-magnetic layer than the second layer. The first layer contains a heusler alloy which is at least partially crystallized. The second layer includes a ferromagnetic body which is at least partially crystallized, unlike the heusler alloy. The first layer and the second layer include a first atom added. The first atom is one selected from the group consisting of Mg, Al, Cr, Mn, Ni, Cu, Zn, Pd, Cd, In, Sn, Sb, Pt, Au, and Bi.SELECTED DRAWING: Figure 1

An automatic power-on / off structure for rotation-and-flip operations of a night-vision device is provided, relating to the technical field of night-vision devices. The structure includes a frame, two pivot arms, two night-vision scopes, two magnets, and two Hall sensors. Through the interaction between the magnets and the Hall sensors, i.e., a non-rigid contact, the structure enables automatic powering on of a night-vision scope when in use and automatic powering off when not in use. Specifically, when a pivot arm drives the corresponding night-vision scope to rotate to a certain angle, the magnet enters the sensing range of the Hall sensor, thereby triggering a signal to power on that night-vision scope. Conversely, when the pivot arm drives the night-vision scope away from the sensing range, that scope is automatically powered off. In addition, the pivot shaft connecting the pivot arm and the frame includes an adjustable damping feature, and sealing rings are provided at the contact portions to ensure dustproof and waterproof performance, allowing the structure to adapt to a wide range of operating conditions.

Enhanced EPI techniques are described that acquire and record a second set of scan data with the same flyback trajectory as that used to acquire a first set of scan data, only with a shifted starting point. Doing so ensures that both Nyquist ghosting and flow ghosting can be improved without changing a necessary echo spacing. This also reducing imaging distortion and chemical shift, and without changing the bipolar readout gradient. A full set (according to Nyquist) of all k-space lines can be yielded for each polarity of the bipolar readout gradient.

A motor drive controller for driving a brushless direct current motor includes a motor drive unit; a magnetic sensor for detecting a magnetic field generated by rotation of the motor and outputting the magnetic field as each of magnetic signals; and a bias adjuster for adjusting and outputting a bias voltage used in magnetic field detection by the magnetic sensor. The bias adjuster adjusts the bias voltage to a second voltage value lower than a first voltage value that allows the magnetic sensor to detect the magnetic field in a first period after a phase change of the magnetic signals. The bias adjuster also adjusts the bias voltage to a first voltage value in a second period from an end of the first period until a subsequent phase change of the magnetic signals.

By extending the lifespan of the refrigeration unit and reducing the frequency of replacement, the operating rate of the MRI system will be improved. [Solution] The cold head life extension mode is implemented. In the cold head life extension mode, the refrigerator's displayer is operated at a constant frequency lower than a predetermined upper frequency, regardless of the temperature of the superconducting coil, and the compressor inverter controls the drive frequency of the compressor drive unit according to the temperature of the superconducting coil.

The invention relates to an apparatus (10) for monitoring a patient undergoing a magnetic resonance image (MRI) scan. The apparatus comprises an input unit (20), a processing unit (30) and an output unit (40). The input unit is configured to provide the processing unit with at least one sensor data of a patient undergoing an MRI scan of an MRI scanner. The input unit is configured to provide the processing unit with at least one scan parameter of the MRI scanner for the MRI scan. The input unit is configured to provide the processing unit with at least one characteristic of the patient. The processing unit is configured to predict a stress level of the patient and / or a predicted motion state of the patient, one or more predictions comprising utilizing the at least one sensor data of the patient, the at least one scan parameter of the MRI scanner and the at least one characteristic of the patient. The output unit is configured to output information related to the predicted stress level of the patient and / or the predicted motion state of the patient.

A system for automatic assessment of therapy outcome in cancer patients treated with radiation therapy, the system comprising a machine-learning-based segmentation model for delineating tumours longitudinally in serial magnetic resonance imaging (MRI) with high precision. Longitudinal segmentations of tumour before and / or during treatment and / or at multiple follow-up sessions after the radiation therapy permits monitoring changes in tumour size and is used in the system for automatic assessment of therapy outcome based on standard clinical criteria.

A method and sensing system for determining an electromagnetic property of a material is disclosed. The method and system comprise applying a first time varying magnetic field at a modulation frequency to the material located in a sensing region and operating a resonant detection circuit at an operating frequency higher than the modulation frequency where the resonant detection circuit is for sensing a material response upon application of the first time varying magnetic field to the material in the sensing region. The method and system further comprise determining an impedance characteristic of the resonant detection circuit; and then processing the impedance characteristic to determine the electromagnetic property of the material.

Disclosed herein is a power management system (100) for a magnetic resonance imaging magnet (102) comprising a power supply (104) configured for powering the magnetic resonance imaging magnet. The power management system further comprises an electrical power storage system (112). The power management system further comprises an energy recovery system (106) configured for discharging electrical power from the magnetic resonance imaging magnet and storing the electrical power in the electrical power storage system when the power supply ceases powering the magnetic resonance imaging magnet. The power management system is further configured for at least partially powering the magnetic resonance magnet using the electrical power storage system.

A biomagnetic sensor that incorporates an integrated active noise cancellation unit that uses a gradiometer to remove ambient magnetic noise from a detection signal obtained from a tunnelling magnetoresistive (TMR) sensor unit that is indicative of a magnetic field adjacent to biological tissue. The ambient magnetic noise can thus be removed in real time at a front end of the sensor (e.g. as part of circuitry in the sensor body itself). The active noise cancellation technique proposed herein may be effective enough to enable the biomagnetic sensor to be used in an unshielded environment (i.e. an environment that is subject to the Earth's magnetic field, for example), which widens significantly the potential uses for the sensor.

This invention relates to a passive shimming layer and a magnetic resonance imaging (MRI) device. The passive shimming layer includes a support assembly, a shimming strip assembly, and a fixing assembly. The support assembly includes an elastic element and multiple support strips, which are sequentially fixed to the inner wall of a main magnet along a circumferential direction. The elastic element has an arc-shaped structure and is disposed on the inner side of the multiple support strips, so that an elastic cavity is formed between two adjacent support strips, the elastic element, and the main magnet. The shimming strip assembly is inserted into the elastic cavity. By setting the elastic element and support strips, an elastic cavity is formed between two adjacent support strips, the elastic element, and the inner wall of the main magnet. During installation, the shimming strip assembly only needs to be inserted into the elastic cavity, and the elastic element will press the shimming strip assembly tightly against the inner wall of the main magnet, thereby ensuring that the shimming strip assembly is firmly fixed within the elastic cavity, reducing vibration of the shimming strip assembly and improving imaging quality.

Provided is an electric current sensor comprising: a first bus bar (10A), a second bus bar (10B), and a third bus bar (10C) through which a three-phase AC current flows; a first sensor unit (20A) having a first magnetic detection element (30A) and a second magnetic detection element (30B); and a second sensor unit (20B) having a third magnetic detection element (30C) and a fourth magnetic detection element (30D), the first sensor unit (20A) being disposed between two bus bars other than one arbitrary bus bar to be measured from among the first through third bus bars, the second sensor unit (20B) having as a measurement object one of the two bus bars other than the one bus bar to be measured, and being disposed between the one bus bar to be measured and the other of the two bus bars other than the one bus bar to be measured, the distance between the first magnetic detection element (30A) and the one of the two bus bars other than the one bus bar to be measured and the distance between the second magnetic detection element (30B) and the other of the two bus bars other than the one bus bar to be measured being substantially equal, and the distance between the third magnetic detection element (30C) and the other of the two bus bars other than the one bus bar to be measured and the distance between the fourth magnetic detection element (30D) and the one bus bar to be measured being substantially equal.

A system includes a stator, and a first carrier and a second carrier disposed over a horizontal surface of the stator. A plurality of electromagnetic coils are disposed in an array beneath the horizontal surface. The first carrier and the second carrier each include plurality of magnets arranged in an array and are configured to support a first substrate and a second substrate, respectively. A controller is configured to individually energize each of the plurality of electromagnetic coils, which causes the first carrier and the second carrier to levitate above the horizontal surface and independently move in a loop relative to the horizontal surface. The plurality of electromagnetic coils can apply a differential force to adjust a planar alignment of the first substrate or the second substrate, and a metrology tool can take one or more measurements of the first substrate or the second substrate.

A magnetic sensor head includes an optical fiber, a GI fiber having one end optically connected to the optical fiber, a magnetic film joined to the other end of the GI fiber, and a reflective film joined to a surface of the magnetic film opposite a surface joined to the GI fiber. The magnetic film is formed of a rare-earth iron garnet film. The slope of the sum of squared differences of the rare-earth iron garnet film with respect to an applied magnetic field is 100 or greater.

Aspects of the present disclosure provide a power activation module for powering one or more wearable electronic components. The power activation module includes a switch configured to provide a path for current flow between a battery associated with the power activation module, the one or more wearable electronic components, and a ground terminal. The power activation module also includes a sensor configured to detect whether a signal is applied to the sensor and, based on the detection, output a first digital output signal for controlling, at least in part, the switch to control the current flow from the battery to the one or more wearable electronic components. The power activation module also includes a lock pin configured to receive a lock signal, wherein when the lock signal is received, the switch is locked to allow current flow from the battery to the one or more wearable electronic components.

Disclosed herein is a method for synchronizing MRI data acquisitions of a heart of a subject (118) with a cardiac cycle of the heart using photoplethysmography data (320; 410). The method comprises receiving the photoplethysmography data (320; 410), detecting a first cardiac trigger (322; 412), which is indicative of a start of a first ventricular systole (420) of a first cardiac cycle, using the received photoplethysmography data (320; 410), and, in response to the detecting of the first cardiac trigger (322; 412), performing a time-delayed first triggering of a first magnetic resonance imaging data acquisition before a start of a ventricular contraction of a second ventricular systole (434) of a second cardiac cycle following the first cardiac cycle.