387 results about "Magnetic field gradient" patented technology

The invention discloses a multi-sensor information fusion method for monitoring the insulation state of a high-voltage cable, and relates to the technical field of information. The method comprises the following steps: acquiring magnetic flux distribution data at different spatial positions in a grounding box according to a three-axis orthogonal magnetic flux sensor, and analyzing magnetic flux distribution characteristics to obtain a spatial sensitivity distribution map; the method comprises the following steps: acquiring a magnetic field signal generated by a cable fault discharge source, decomposing and calculating a magnetic field gradient tensor by adopting an inversion method based on the magnetic field gradient tensor, positioning a defect position of cable insulation, and acquiring three-dimensional space coordinate information of the defect position; according to a cable insulation state space distribution evaluation result, the arrangement density of the fluxgate sensors is increased in an insulation fault high-incidence area, the arrangement of the tetrahedral configuration sensor array is optimized, and a comprehensive evaluation index system is constructed. Data support is provided for state monitoring and life prediction, and the operation reliability of the cable is improved.

The invention relates to the technical field of power batteries, in particular to a power battery pack health state detection method and system. The power battery pack health state detection method comprises the following steps: acquiring open-circuit voltage change data and terminal voltage fluctuation data of a battery under micro current pulse excitation, recording a change curve of voltage along with time through high-precision time sequence acquisition equipment, and obtaining an initial data set of voltage dynamic response; acquiring magnetic field intensity distribution and magnetic field gradient change data of the surface of the battery in a weak alternating magnetic field, and acquiring spatial magnetic field information through a magnetic sensor array to obtain a three-dimensional distribution diagram reflecting magnetic field nonuniformity; through a three-dimensional distribution diagram of magnetic field intensity distribution and magnetic field gradient change, a defect detection algorithm is adopted to analyze a mapping relation between magnetic field non-uniformity and internal micro cracks, and correlation distribution of defect positions and internal resistance growth rates is determined.

The invention provides an electrical equipment remote maintenance guidance method and system. The method comprises the following steps: capturing an aperiodic torque waveform and a magnetic field gradient abnormal signal by deploying a torque fluctuation sensor and a magnetoresistive sensor; performing multi-scale frequency band division on the non-periodic torque waveform, screening out a transient high-frequency component in a start-stop stage of equipment, and separating out a magnetic field polarity reversal characteristic from a magnetic field gradient abnormal signal; performing cross-domain matching on the occurrence time of the transient high-frequency component and the spatial orientation of the magnetic field polarity reversal feature to generate a mixed feature mark; calculating a frequency band overlapping degree based on the time-frequency energy distribution marked by the mixed features and generating a coherence map; and matching a fault historical case library according to the coherence map, and outputting a maintenance strategy set aiming at the rotating shaft dynamic unbalance and electromagnetic interference superposition fault. According to the invention, through fusion of torque fluctuation and magnetic field distortion collaborative analysis, the precision of mechanical and electromagnetic composite fault diagnosis of the rotating shaft is improved.

The invention belongs to the technical field of magnetic particle imaging, relates to a magnetic particle imaging reconstruction method based on a calibration magnetic field generation system matrix, and aims to solve the problems that a traditional magnetic particle imaging reconstruction method is poor in applicability in asymmetric bilateral structure magnetic particle imaging equipment (A-MPI) and cannot perform imaging in any region. The method comprises the following steps: performing grid division on an imaging area, calibrating magnetic field intensity, and obtaining magnetic field gradient distribution of each point; obtaining a theoretical system matrix according to a mathematical calculation mode; randomly moving the positions of the non-magnetic field points for scanning to obtain actually measured magnetic field gradient distribution and a system matrix, and constructing a data set; expanding the data set based on the simulation system; constructing a deep learning model, and inputting the extended data set and the measured data into the training deep learning model; and inputting a theoretical system matrix at any position, and obtaining an accurate system matrix by using the trained model. According to the invention, the system matrix at any position can be obtained under the A-MPI equipment, so that imaging at any position is realized.

The invention relates to the technical field of aluminum-based thin film preparation, and discloses an aluminum-based thin film uniform deposition system based on magnetron sputtering. The system comprises a substrate state detection module, a magnetic field dynamic regulation and control module, a sputtering power regulation module, a deposition process monitoring module and a central control terminal. The substrate state detection module collects and transmits surface flatness data of the substrate in real time, and the central control terminal carries out visual display. The magnetic field dynamic regulation and control module obtains magnetic field intensity correction through a magnetic field gradient algorithm according to the deviation value of the real-time flatness parameter and the standard parameter and sends the magnetic field intensity correction to the sputtering power regulation module. And the sputtering power adjusting module adjusts the sputtering rate of the target material accordingly. The deposition process monitoring module tracks the adjusting process, evaluates the dynamic response performance, generates a stable or fluctuation signal and sends the stable or fluctuation signal to the central control terminal, and the central control terminal triggers sound-light alarm when receiving the fluctuation signal. The system can improve the deposition uniformity and process stability of the aluminum-based thin film.

A sensor unit for detecting brain current-induced magnetic fields in an unshielded environment has a plurality of gradiometer units configured for arrangement around a head of a user. Each gradiometer unit has two magnetometers which are arranged at a fixed distance from each other. Each magnetometer has a sensor medium and is configured to detect a magnetic field strength at a measurement location by reading a spin resonance in the sensor medium depending on the magnetic field strength. The sensor unit further includes at least one excitation light source for radiating light into the sensor media of the magnetometer. The sensor unit further incudes at least one signal processing unit for determining a magnetic field gradient at a gradiometer unit as a difference of the output signals of the two magnetometers of the gradiometer unit and for detecting a time course of the magnetic field gradient.

The invention discloses a full-tensor high-order magnetic field gradient sensing system and a use method, the full-tensor high-order magnetic field gradient sensing system comprises a magnetic field sensing probe, a non-metal directional support, a high-strength engineering plastic shell and a communication antenna, the magnetic field sensing probe comprises a pure wood support frame, 15 three-axis magnetic field sensors and a magnetic field acquisition processing communication module; the nine three-axis magnetic field sensors are distributed in an xy plane in a shape like a Chinese character'tian ', and the six three-axis magnetic field sensors are arranged in an xz plane in an upper row and a lower row. The magnetic field sensing probe is installed in the nonmetal directional support through the pure wood supporting frame, and the z-axis of the magnetic field sensing probe is always kept in a plumb downward mode. The plastic sealed shell is wrapped outside the directional support, and the communication antenna is covered on the shell. By adopting the full-tensor high-order magnetic field gradient sensing system and the full-tensor high-order magnetic field gradient sensing method, all first-order and second-order magnetic field gradient parameters can be obtained, so that accurate measurement is carried out.

The invention discloses an ion control method and device, an ion trap system and a related device, and belongs to the technical field of quantum information. A plurality of ions in the ion trap system are in a magnetic field with a magnetic field gradient, the magnetic field gradient enables transition frequencies of the plurality of ions to be different, and each ion is of a multi-energy-level structure. The method comprises the steps that according to the transition frequency of a plurality of first ions, the energy level of the first ions is adjusted so that the first ions irrelevant to quantum control can be transferred from a calculation space to an auxiliary space, and the energy level of the ions in the calculation space is different from the energy level of the ions in the auxiliary space; and performing quantum manipulation on the plurality of second ions in the calculation space to form a plurality of quantum bits. According to the scheme, light finding of ions is not needed, light finding of ions is not needed, multi-ion control can be achieved through global laser or microwaves, and implementation is easy. And moreover, multi-ion control can be realized by using a relatively small magnetic field gradient, and the ion control threshold is reduced.

The invention discloses an exciting current adjusting method for four-pole / eight-pole composite iron. The exciting current adjusting method comprises the following steps: establishing a two-dimensional data comparison table of coil currents of four-pole iron and eight-pole iron; performing experimental measurement to obtain a quadrupole field magnetic field gradient three-dimensional curved surface sample database and an octupole field magnetic field gradient three-dimensional curved surface sample database; performing two-dimensional interpolation on the magnetic field gradient three-dimensional curved surface sample database by using a cubic spline function; a quadrupole field magnetic field gradient plane and an octupole field magnetic field gradient plane are selected and intersect with the quadrupole field magnetic field gradient three-dimensional curved surface sample database curved surface and the octupole field magnetic field gradient three-dimensional curved surface sample database curved surface respectively, and current curves meeting the quadrupole field gradient and the octupole field gradient are obtained; and obtaining an intersection point of the two curves, and using the intersection point as a solution of the compound iron exciting current. According to the invention, based on magnetic field measurement data under a few groups of excitation currents, a large amount of excitation current debugging time is saved, and accurate adjustment of the magnetic field gradient of the composite multi-pole magnet can be realized.

The invention relates to the technical field of crane equipment health monitoring, in particular to a crane running state health monitoring system and method. A sensing data acquisition unit is used for acquiring a winding drum vibration harmonic component, a steel wire rope leakage magnetic field gradient and a pulley block real-time load; the data analysis unit performs rotating speed synchronous variational mode decomposition on the vibration component to extract resonance characteristics, performs temperature and stress double-compensation correction on a leakage magnetic field gradient, quantifies an energy entropy attenuation rate through wavelet packet decomposition, constructs a phase difference model of a load and vibration to output a slip risk phase offset, calculates a load spectrum damage cumulant, and calculates a load spectrum damage cumulant; and after the four heterogeneous features are fused, a residual life coefficient is output through a dual-channel convolution-long and short-term memory hybrid neural network, and an execution unit triggers crane speed reduction control when the residual life coefficient is lower than a threshold value, so that the problems of insufficient multi-source data fusion and lack of dynamic compensation in the traditional technology are solved, and the fault early warning accuracy is improved.

The invention discloses a residual capacity balance control method and system for an aged lithium battery, and relates to the technical field of new energy materials and devices, and the method comprises the steps: inputting quantum magnetic field response data and infrasonic wave signals into a single-chip microcomputer, carrying out the wavelet noise reduction and histogram equalization processing based on an STM32 single-chip microcomputer, and generating an acoustic-magnetic coupling feature matrix; inputting a dynamic pheromone equalization model based on the acoustic-magnetic coupling characteristic matrix, calculating a capacity difference coupling coefficient between the battery packs through an ant colony optimization algorithm, and generating a capacity redistribution path topological graph; according to the capacity redistribution path topological graph, the energy transfer direction is controlled through a bidirectional Buck-Boost circuit, and an equalizing current threshold value is dynamically adjusted based on the quantum spin resonance magnetic field gradient; according to the invention, the quantum magnetic field response data of the aged lithium battery pack and the infrasonic wave signal generated by electrolyte decomposition are collected, so that the physical and chemical states in the battery are accurately monitored.

The invention provides a liquid leakage detection method and device for a liquid cooling device, and the method comprises the steps: obtaining the fluorescence intensity and magnetic field gradient of a surface detection region of the liquid cooling device; wherein the cooling liquid of the liquid cooling device contains a fluorescent marker and a magnetic marker; based on the fluorescence intensity and the magnetic field gradient, determining whether a liquid leakage risk exists in the detection area; in response to the liquid leakage risk of the detection area, obtaining the liquid leakage probability of each grid position of the detection area based on the fluorescence intensity and the magnetic field gradient; and determining a target grid position where liquid leakage occurs in the detection area based on the liquid leakage probability. According to the technical scheme of the invention, the detection precision and detection efficiency of liquid leakage of the liquid cooling device can be improved.

The invention discloses an aviation electromagnetic multi-component data processing method for three-dimensional complex geologic body detection. The method mainly solves the technical problem that it is difficult to visually and accurately judge the spatial position and distribution condition of an abnormal body. Comprising the steps of obtaining six-component magnetic field detection data; preprocessing the six-component magnetic field detection data, and preliminarily distributing the dynamic weight of the preprocessed six-component magnetic field data; establishing an electromagnetic field forward modeling equation, simulating six-component magnetic field response by using an electromagnetic field forward modeling model, generating corresponding simulated six-component magnetic field response data, and comparing the simulated six-component magnetic field response data with six-component magnetic field detection data to form constraint conditions of an inversion process; carrying out the spatial enhancement of the anomalous body of the three-dimensional complex geologic body in combination with a Laplace operator and the second derivative of the magnetic field gradient component after the initial distribution of the dynamic weight; building a multi-modal network; and inputting the preprocessed six-component magnetic field data into a multi-modal network to obtain a three-dimensional resistivity model or geologic body probability distribution corresponding to the three-dimensional complex geologic body.

A system for controlling a translocation speed of a molecule through a nanopore may include a fluid chamber containing a solution with a magnetic susceptibility that is different from the magnetic susceptibility of the molecule, a nanopore situated in the fluid chamber, and at least one magnetic component configured to create a magnetic field gradient within the solution to control the translocation speed of a molecule through the nanopore. A system for controlling a translocation speed of a molecule through a nanopore may include a nanopore at least one magnetic component situated to create a magnetic field that causes the molecule to experience a rotational torque as it passes through the nanopore.

An array of spin qubits relies on a gradient magnetic field to ensure that the qubits are separated in frequency in order to be individually addressable. Furthermore, a strong magnetic field gradient is required to electrically drive the EDSR of the qubits. Quantum dot devices and related methods and systems that integrate magnetic materials in the gates to provide a gradient magnetic field are disclosed. Magnetic materials in different gates may be of different heights to improve frequency separation of neighboring qubits. Unlike previous approaches to quantum dot formation and manipulation, various embodiments of the quantum dot devices disclosed herein may enable improved control over magnetic fields and their gradients to realize better frequency targeting of individual qubits, help minimize adverse effects of charge noise on qubit decoherence and provide good scalability in the number of quantum dots included in the device.

The invention relates to the technical field of measurement, in particular to a well deviation and geomagnetic field intensity measurement system based on a high-precision fluxgate sensor. Comprising a fluxgate sensor group, a magnetic field data analysis part and a measurement result calculation part, the fluxgate sensor group comprises high-precision fluxgate sensors for respectively measuring magnetic field components in the X-axis direction, the Y-axis direction and the Z-axis direction; the magnetic field analysis part is used for constructing a magnetic field gradient tensor according to the physical parameters of the high-precision fluxgate sensor, the effective magnetic conductivity and the corrected magnetic field component in each direction, and separating a geomagnetic field vector from the total magnetic field vector according to the magnetic field gradient tensor; and the measurement result calculation part is used for calculating a hole drift angle value and an azimuth angle value according to the geomagnetic field vector. According to the method, the precision, robustness and environment adaptability of underground magnetic field measurement are remarkably improved. The geomagnetic field vector can be accurately extracted, and high-precision calculation of the hole drift angle and the azimuth angle is achieved.

The invention provides an easy-to-scale efficient biological magnetic separation system and method and application. The magnetic separation method comprises the following steps: marking a target object in a to-be-detected suspension by adopting magnetic nanoparticles, and putting the marked to-be-detected suspension into a separation container; a modularized magnet array is arranged in the separation container, the modularized magnet array is composed of permanent magnets, and the permanent magnets are assembled into the cuboid modularized magnet array; the surface of the permanent magnet is coated with a polytetrafluoroethylene coating; the modularized magnet array moves in the suspension under the control of a driving magnet arranged outside the separation container to generate a dynamic gradient magnetic field, and a target object is captured by the modularized magnet array under the action of the gradient force of the magnetic field; removing the liquid in the separation container; adding the resuspension into a separation container, and recovering a target object by physical ultrasonic washing; or adding a chemical dissociation solution into the separation container to recover the target object.

The invention provides an oil and gas pipeline safety state monitoring method and system, and the method comprises the steps: firstly, obtaining the pipeline information, field working condition information and an initial stress value of a target oil and gas pipeline; then, a test pipeline is determined, a pipeline water pressure-far field magnetic signal test device is arranged, a plurality of preset water pressures are loaded to the test pipeline through the pipeline water pressure-far field magnetic signal test device, and a plurality of test magnetic field gradient moduli and a plurality of test stress values corresponding to the test pipeline under the plurality of preset water pressures are obtained; next, matching correction is carried out, and a corrected first pipeline stress value variable quantity calculation model and a corrected second pipeline stress value variable quantity calculation model are determined so as to be used for determining the monitoring stress value of the target oil and gas pipeline. And finally, performing safety state evaluation on the target oil and gas pipeline according to the monitored stress value. In this way, the accuracy of monitoring the stress state of the oil and gas pipeline can be improved through the corrected pipeline stress value variation calculation model, and therefore the accuracy of monitoring the safety state of the oil and gas pipeline is improved.

The invention discloses an attitude immune pedestrian double-magnetic speed measurement method and device, and belongs to the technical field of indoor pedestrian positioning. According to the method, a static attitude projection method is adopted, and the problems of pedestrian attitude change, magnetometer zero offset and magnetometer installation inconsistency are solved; a double-window weighted dynamic time warping algorithm is adopted, the capacity of capturing the change trend of the magnetic field is improved, the capacity of dynamically adjusting the magnetic field intensity and the contribution degree of the change trend in a cost function is improved, meanwhile, the influence of transient disappearance of the magnetic field gradient on a matching result is reduced, and the matching speed and the matching precision are improved; therefore, the pedestrian movement speed can be accurately estimated.

The invention discloses a magnetic circuit structure for adjusting the gradient of a magnetic field in a Hall thruster channel, relates to the technical field of Hall thrusters, and solves the problems that a krypton working medium Hall thruster is insufficient in krypton working medium ionization and low in thruster efficiency. The device comprises magnetic poles, an inner iron core, a bottom plate, a magnetic screen, an outer magnetic conductive cover, a coil and an annular channel, the inner iron core is arranged at one end of the upper surface of the bottom plate, the outer magnetic conductive cover is arranged at the other end of the upper surface of the bottom plate, and the magnetic poles are arranged at the upper ends of the inner iron core and the outer magnetic conductive cover; a magnetic screen is arranged on the bottom plate and comprises an inner magnetic screen and an outer magnetic screen, and an annular channel is arranged between the inner magnetic screen and the outer magnetic screen; a coil is arranged between the inner magnetic screen and the inner iron core, and a coil is arranged between the outer magnetic screen and the outer magnetic conductive cover; and grooves are formed in the inner magnetic screen and the outer magnetic screen. By adjusting the thicknesses of different positions of the magnetic screen, the magnetic flux density is saturated, so that the magnetic field distribution in the channel is changed, the magnetic field gradient is reduced, the length of an ionization area is increased, and the krypton working medium is ionized more sufficiently in the channel.

The invention discloses a nuclear magnetism safety interval confirmation device, and the device comprises a quantum noise suppression module which is used for eliminating radar signal noise caused by the quantum tunneling effect on the surface of a metal object in an ultrahigh field intensity environment; the multi-sensor fusion center is used for integrating the radar cleaning signal, the real-time magnetic field intensity data and the terahertz penetrability detection result to generate fused object position information; the dynamic magnetic field reconstruction engine is used for calculating a magnetic field distortion gradient by analyzing Hall sensor array data and a magnetohydrodynamic model in real time; the nonlinear danger scoring module is used for receiving object distance, magnetic field gradient, existence time and object classification data; the hierarchical response system is used for triggering a corresponding response according to the danger score; and the cesium atomic clock synchronization module is used for eliminating a timing error caused by a time crystal effect through a block chain timestamp verification mechanism. According to the invention, risk closed-loop control in a high-field-intensity MRI environment is truly realized.

The invention belongs to the field of magnetic particle imaging, particularly relates to a zero-inertia magnetism gathering ring magnetic-field-free line magnetic particle imaging system and method, and aims to solve the problems of low magnetic field gradient, high magnetic field control complexity and limited imaging space. The current of a gradient magnetic field coil group is generated by a magnetic field control and imaging module, is output by a signal acquisition and output module, and is amplified and provided by a gradient power amplifier module. The current of the axial excitation magnetic field coil is generated by the magnetic field control and imaging module, is output by the signal acquisition and output module and is amplified and provided by the excitation power amplifier module, and a signal received by the multi-axis detection coil is filtered and amplified by the signal processing unit and then is input to the imaging module by the magnetic field control and imaging module for algorithm reconstruction. According to the invention, the magnetic field gradient and the control precision are obviously improved, and the imaging space of the axial fault plane is realized.

The invention discloses a copper wire tinning method for tinned copper stranded wire production, which relates to the technical field of metal surface treatment, and comprises the following steps: releasing a copper wire to an ionic liquid electrophoresis tank, applying an electric field to strip surface oxides, and then carrying out three-stage countercurrent rinsing to generate a clean copper wire; putting the clean copper wire into a composite plating tank, monitoring the tin liquid viscosity and the copper wire linear speed in real time, calculating the magnetic field gradient, and controlling tin crystal oriented growth according to the magnetic field gradient to generate an oriented crystallization tinned copper wire; the surface temperature of the directionally crystallized tinned copper wire is monitored in real time and compared with a preset temperature threshold value, a temperature permission trigger signal is generated, the annular array spray gun is triggered to work according to the temperature permission trigger signal, and a densified tinned copper wire is generated; and the densified tinned copper wire is scanned through a micro-focus CT scanner, a gap three-dimensional point cloud picture is generated, the gap size and the normal angle of the gap three-dimensional point cloud picture are analyzed, the optimal spraying parameters are recognized, and the passivation film tinned copper wire is generated.

The invention discloses liquid dressing production equipment, and relates to the technical field of medical instrument production equipment.The liquid dressing production equipment is characterized in that firstly, neodymium iron boron magnets of a driving rotary disc and a driven rotary disc are in coupling transmission, and a middle isolation sleeve is matched, so that complete physical isolation inside and outside a kettle is achieved; a uniform magnetic field generated by Helmholtz coils is used for weakening attraction force among particles, a dynamic magnetic field gradient formed by rotation of a permanent magnet arranged in a stirring paddle can cooperate with mechanical shearing, so that the internal structure of an aggregate is deeply destroyed, meanwhile, the Helmholtz coils in three orthogonal directions provide a global uniform static magnetic field, and the aggregate is fully dispersed. The stability of the magnetic background in the kettle can be ensured, the global effect of the dynamic magnetic field gradient is matched, the local defect caused by purely depending on mechanical shearing is avoided, the dispersion uniformity is remarkably improved, the influence of the concentration gradient on the physical and chemical properties is reduced, and the influence of initial agglomeration on the subsequent process can be reduced by utilizing the efficient dispersion capacity of the magnetic mixing assembly.

The invention relates to the technical field of electromagnetic measurement, and discloses a measurement unit stabilization method and system, electronic equipment and a storage medium, and the method comprises the steps: obtaining three-dimensional displacement trajectory data in real time, and building a motion error compensation model containing a mechanical vibration direction vector and a phase offset; on the basis of asymmetric magnetic pole distribution, combined with phase difference calculation of a magnetic circuit gradient direction vector and a mechanical vibration direction vector, a closed loop current orthogonal to the mechanical vibration direction vector is generated on an interface to realize gradient isolation; based on a multi-branch common-mode suppression mechanism, an interference signal reaches a preset attenuation amplitude before a loop is closed through combination of a magnetic core impedance matching characteristic and an eddy current effect; and performing dynamic matching based on the displacement parameter and an electromagnetic interference attenuation result, adjusting a magnetic pole inclination angle in real time, and forming a closed-loop control path of magnetic field gradient compensation and mechanical vibration suppression. According to the invention, the stability and anti-interference capability of the measuring unit under severe working conditions can be improved.

The invention relates to the field of control valve positioning, and discloses a high-precision positioning system of a water treatment multi-path control valve based on magnetic induction. Through rigid linkage of the magnet and the valve element driving unit, accurate mapping of magnet rotation / linear motion and valve element stations is achieved. A sensing device array is adopted to detect the gradient change of a three-dimensional magnetic field in a non-contact manner along the movement track of a magnet, and the sensor array is arranged in a circumferential annular or axial linear manner. A pre-calibrated magnetic field intensity-spatial position multi-dimensional database and a two-stage matching strategy are adopted. For long-stroke application, a sensor relay detection technology is adopted. The method has the advantages of high precision, high reliability and low cost, and is suitable for the fields of water treatment, industrial automation and the like.

The embodiment of the invention provides a current magnetic source inversion positioning method and device based on a unidirectional magnetic field gradient, and the method comprises the steps: determining a fluxgate probe, and determining an auxiliary testing tool based on the fluxgate probe; wherein the auxiliary test tool comprises a two-dimensional grid; acquiring magnetic field data through a fluxgate probe based on the two-dimensional grid; determining magnetic field gradient data based on the magnetic field data, and determining a current density distribution based on the magnetic field gradient data; and determining current magnetic source position information based on the current density distribution. The method comprises the following steps: acquiring magnetic field data through a fluxgate probe based on a two-dimensional grid; determining magnetic field gradient data based on the magnetic field data, and determining a current density distribution based on the magnetic field gradient data; the current magnetic source position information is determined based on the current density distribution, and the diagnosis of the current state in the equipment and the judgment of the abnormal current value can be realized.

The invention relates to the technical field of magnetic field measurement error compensation, in particular to a single-axis Hall surface magnetic rapid imaging analysis system, which is characterized in that a magnetic field gradient real-time analysis unit calculates a magnetic field gradient change rate through a sliding window weighted difference algorithm, identifies a magnetic pole transition region and analyzes the magnetic field gradient change rate. The multi-source error coupling modeling unit synchronizes Hall probe spacing fluctuation, inclination angle and magnetic field gradient data and constructs a composite compensation function, the adaptive compensation unit corrects and counteracts spacing attenuation and projection errors through two-stage assembly lines, and the nonlinear trigger control unit generates an adaptive encryption trigger signal, so that the sampling spacing decreases progressively along with the gradient change rate, and the error compensation is realized. And the magnetic field distribution reconstruction unit fuses the compensation data and the sampling sequence, reconstructs a continuous magnetic field distribution curve by adopting gradient constraint cubic spline interpolation, accurately outputs a magnetic pole boundary position and a surface magnetic field intensity quantification result, and improves the surface magnetic imaging precision and efficiency.

The present invention concern a method and a device for the isolation of non-magnetic cells from a heterogeneous sample solution containing biological material including desired and undesired cells. The method comprises the steps of: —adding magnetic or magnetizable particles to the sample, wherein said particles have sizes in a range from 100 nm to 4 μm and exhibit surface components which support specific association with target cells, wherein said target cells comprise are either said desired or said undesired cells; —decreasing said external magnetic field gradient; —incubating said sample solution with said magnetic particles to obtain a magnetized cell fraction; —washing said magnetized cell fraction using a washing solution to reduce non-specific binding; —increasing said external magnetic field gradient; —separating said magnetized cell fractionation of target cells from said sample; wherein said sample solution is subjected to an external magnetic field gradient throughout said adding, incubating, washing and separating steps, and wherein said sample solution is rotated at least during said adding, incubating and washing steps.

A magnetic resonance imaging apparatus according to an exemplary embodiment includes a magnet, a gradient magnetic field coil, a sequence controller, and a plurality of metal shims. The magnet generates a static magnetic field. The gradient magnetic field coil applies a gradient magnetic field to a subject. The sequence controller applies a current to the gradient magnetic field coil by executing a first pulse sequence. The plurality of metal shims is used for passive shimming in which the plurality of metal shims is arranged based on the static magnetic field distribution in a state where a temperature of the gradient magnetic field coil is increased by execution of the first pulse sequence. The sequence controller executes a second pulse sequence for imaging the subject after completion of the passive shimming.