35 results about "Nuclear magnetic resonance" patented technology

This invention relates to crack resonance whorl testing method, which belongs to iron magnetic material lossless electro-magnetic testing field. This invention uses resonance circuit to generate pulse resonance signals to excite sensor ring to get whorl field to judge the crack existence through test ring. The advantage lies in improving extracting highness and overcomes the rough surface impact to realize spot test to fulfill traditional testing rough crack.

A magnetic recording medium includes a first magnetic layer; and a second magnetic layer formed on the first magnetic layer. The first magnetic layer and the second magnetic layer make exchange coupling therebetween and also, have their magnetizing direction in anti-parallel to one another. A net residual area magnetization of the first magnetic layer and the second magnetic layer is expressed by the following formula: |Mr1×t1−Mr2×t2| where Mr1 and Mr2 denote respective residual magnetizations of the first magnetic layer and the second magnetic layer, and t1 and t2 denote respective film thicknesses of them; and the net area magnetization at a first temperature is larger than the net area magnetization at a second temperature lower than the first temperature.

The invention discloses a magnetic nano particle magnetic-induction thermal focusing system based on a complex magnetic field, comprising a device for generating an alternating magnetic field and magnetic nano particles, wherein the device for generating the alternating magnetic field generates the alternating magnetic field; the magnetic nano particles are dispersed in the alternating magnetic field; the magnetic nano particle magnetic-induction thermal focusing system also comprises at least two permanent magnets which are distributed at the two sides of the device for generating the alternating magnetic field, and the same poles are opposite; and the distances from the permanent magnets to the central line of the device generating the alternating magnetic field are approximately equal. In the magnetic nano particle magnetic-induction thermal focusing system, the accurate control of the magnetic nano particle heat effect and selective temperature increasing of local positions in areas dispersed with magnetic nano particles are realized, the cost is lower, and the selective heating on tumor areas can be realized, so that the damage of thermal therapy to the normal tissues is relieved. The magnetic nano particle magnetic-induction thermal focusing system also can be applied in selective heating to areas of chemical reaction systems, so that the purpose of controlling the chemical reaction rate is achieved.

In a method and a magnetic resonance imaging system to generate magnetic resonance image data of an object, during the acquisition of magnetic resonance raw data, different transverse magnetizations are excited in multiple sub-volumes to be depicted and used for imaging. These different transverse magnetizations are simultaneously present in at least one time interval of the measurement. Image data are reconstructed from the acquired raw data.

The invention relates to a method for detecting the skin burn depth based on unilateral nuclear magnetic resonance sensing equipment, and belongs to the field of nuclear magnetic resonance detection. The structure of the unilateral nuclear magnetic resonance sensing equipment mainly comprises a permanent magnet structure, a radio-frequency coil, a gradient coil and a radio-frequency shielding device. The gradient coil conducts spatial encoding; a natural gradient perpendicular to the surfaces of magnets is taken as a selective layer gradient according to the characteristics of a magnetostatic field formed by the unilateral magnets, bi-phase encoding is conducted instead of frequency encoding, and according to the difference of the skin longitudinal relaxation time T1, the skin transverse relaxation time T2 and the diffusion coefficient D measured through obtained magnetic resonance signals, the skin burn depth can be detected. According to the method, the characteristic that the magnetostatic field formed by the unilateral magnets has a longitudinal gradient is fully utilized, and thus the loss of radio frequency energy is reduced; the defect that the signal-to-noise ratio is low is overcome with an accumulation method, signals are constantly restored with a series of 180-degree refocused pulses, and the signal-to-noise ratio can be increased after the signals are superposed and averaged.

A magnetic field generator includes a power source and a segmented or un-segmented coil connected to the power source to generate a time-varying magnetic field. Energy is applied to the coil so that the coil generates a time-varying magnetic field gradient with a magnitude of at least 1 milliTesla per meter and a rise-time of less than 10 microseconds. The coil may be comprised of overlapping, non-overlapping or partially overlapping coil segments that may individually energized to further improve the operating characteristics of the coil to further decrease bio-effects in magnetic resonance imaging through the use of reduced pulse lengths and multi-phasic magnetic gradient pulses.

The invention discloses a magnetothermal effect-based magnetic field measurement method. The method is mainly characterized in that magnetic energy is absorbed in an alternating magnetic field to generate heat by using ferroferric oxide nanoparticles, and the total effective refractive index of a waveguide is changed, so that an output resonance peak of a magnetothermal effect-based silicon micro-ring magnetic field sensor shifts to achieve magnetic field measurement. The method has the advantage that the magnetic field measurement range is improved. Meanwhile, the invention provides a magnetic field sensor based on the method; the size of a traditional magnetic field sensor is reduced by using the advantages of a high quality factor of the magnetic field sensor and the magnetothermal effect of the magnetic nanoparticles; a solid foundation is laid for integration, intelligentization and miniaturization of the magnetic field sensor; meanwhile, the structure is simple; the sensitivity of the sensor can be changed through optimizing the size design of the sensor and the properties of the magnetic nanoparticles; and the magnetic field sensor is flexibly applicable to various scenarios. Meanwhile, the invention provides a magnetic field sensor-based preparation method, and the preparation method has the advantage that the manufacturing efficiency is improved.

The invention provides a two-stage superconducting quantum interference device amplification device, a method and an SQUID magnetic sensor. The amplification device comprises a modulation module which converts a square wave modulation signal of fixed frequency into modulation magnetic flux, a first-stage superconducting quantum interference device which detects an external magnetic flux signal to acquire measured magnetic flux, and at the same time modulates the voltage output of the measured magnetic flux into a modulated voltage signal through coupled modulation magnetic flux, a shaping conversion module which converts and shapes the modulated voltage signal to output an adjustment magnetic flux signal, a second SQUID magnetic flux-voltage conversion module with self-resetting and transmission characteristic hysteresis, and a demodulation module. The second SQUID magnetic flux-voltage conversion module comprises a second-stage superconducting quantum interference device which is coupled to the shaping conversion module, responds to the adjustment magnetic flux signal, and outputs an adjustment voltage signal corresponding to the amplification. The demodulation module uses the square wave modulation signal to demodulate the adjustment voltage signal, and outputs a two-stage amplified detection voltage signal corresponding to the measured magnetic flux. According to the invention, the problems of work point multi valuedness and work stability of a two-stage SQUID amplification technology are solved.

The invention discloses a nuclear magnetic resonance image automatic classification method and device based on an MDCLSTM-LdenseNet network, and belongs to the field of medical image processing. The method comprises the following steps: obtaining nuclear magnetic resonance images of different types of subjects; preprocessing the nuclear magnetic resonance image to obtain a training data set, a verification data set and a test data set; training is carried out on the constructed MDCLSTM-LDenseNet network model, so that the MDCLSTM-LDenseNet network model can be obtained; inputting the test dataset into the trained MDCLSTM-LDenseNet network model to carry out a test; obtaining classification results of the nuclear magnetic resonance images of the three types of subjects with normal cognition, mild cognitive impairment and Alzheimer's disease and classification accuracy of the MDCLSTM-LdenseNet network model; according to the method and the device, used data sets are strictly divided; data leakage is avoided; the method is advantaged in that the training data set, the verification data set and the test data set are not intersected, reliability of classification results of normal cognition, mild cognitive impairment and Alzheimer's disease is guaranteed, classification accuracy is higher, the missed diagnosis rate and the misdiagnosis rate are lower, and doctors can be more effectively and reliably assisted to diagnose Alzheimer's disease.

Magnetic members of a high-sensitivity magnetoimpedance element and a low-sensitivity magnetoimpedance element are connected to each other in series, and the strength and direction of an external magnetic field is detected on the basis of an impedance variation of this series circuit. The output of a magnetic field detection sensor mainly reflects an impedance variation of the high-sensitivity magnetoimpedance element in a weak magnetic field range, and mainly reflects an impedance variation of the low-sensitivity magnetoimpedance element in a strong magnetic field range, whereby continuous detection is enabled in a wide range from a weak magnetic field to a strong magnetic field.

A wireless magnetic resonance imaging scanner has one or more local coils, a microwave antenna array, and a local oscillator, and an upconverter. The local oscillator signal from the local oscillator is transmitted from the microwave antenna array to illuminate the local coils. The local coils generate magnetic resonance signals at a first frequency and the magnetic resonance signals at the first frequency are upconverted in the upconverter to microwave frequencies. The local oscillator operates at a frequency within an unlicensed band, chosen such that desired sidebands for reception of the upconverted local coil magnetic resonance signals fall outside the unlicensed band.

For the purpose of providing an RF coil apparatus capable of forming an arbitrary FOV, a A magnetic resonance imaging apparatus is provided for collecting magnetic resonance signals while applying a static magnetic field, a gradient magnetic field and an RF magnetic field to a subject to be imaged, and producing an image based on the magnetic resonance signals, the apparatus comprising: an RF coil (108) for conducting at least one of the application of the RF magnetic field and reception of the magnetic resonance signals, in which RF coil, ratios of the electric currents flowing through a plurality of coil elements connected in parallel are adjusted by adjusting device (110, 160, 170).

The invention discloses a deep learning magnetic resonance spectrum reconstruction method based on matrix decomposition, and relates to a magnetic resonance spectrum reconstruction method. The methodcomprises the following steps: 1) generating a time domain signal of a magnetic resonance spectrum by utilizing an exponential function; 2) establishing a training set containing full-sampling time domain signals and under-sampling time domain signals; 3) designing a deep learning network structure based on matrix decomposition; 4) designing a data verification layer of the deep learning network based on matrix decomposition; 5) designing a feedback function of the deep learning network based on matrix decomposition; 6) generating a spectrum reconstruction model of the deep learning network based on matrix decomposition; 7) training relative optimal parameters of the network; 8) reconstructing a magnetic resonance signal needing undersampling reconstruction, and 9) performing Fourier transform on the reconstructed time domain signal to obtain a reconstructed spectrum. the magnetic resonance signal reconstruction method has the advantages that the magnetic resonance signal reconstruction method not only has excellent time performance of a deep learning method, but also has relatively reliable theoretical support on the basis of a traditional reconstruction method, and the magnetic resonance signals can be rapidly reconstructed in a high-quality manner.

The invention discloses a split-type magnetic resonance imaging system, which comprises a body, a supporting table and a sliding table, wherein the upper end surface of the sliding table is provided with a noise reduction device; the noise reduction device comprises a noise reduction box and an upper cover body; a headrest is arranged in the noise reduction device; two sides of the headrest are symmetrically provided with a noise reduction earphone; the inner wall of the upper cover body is provided with an audio and video screen; noise reduction composite plates are embedded into the noise reduction box; two sides of the sliding table are symmetrically provided with sliding chutes; and a sound-proof plate is clamped in the sliding chutes in a sliding way. By use of the split-type magneticresonance imaging system, the sliding table is provided with the noise reduction box, multiple layers of noise reduction composite plates are embedded into the noise reduction box so as to realize multilevel absorption of noise, the noise reduction earphones and the audio and video screen are configured in the box body, while noise is isolated, multimedia audio and video service is provided for apatient, the attention of the patient is distracted, and the irritable emotion of the patient is lowered. The split-type magnetic resonance imaging system is also provided with the push-and-pull sound-proof plate, the sound-proof plate is for plugging the empty cavity of the body so as to further prevent noise from spreading, and through multiple noise reduction processing, a harmful degree of noise borne by the patient is greatly lowered.

The invention discloses a magnetic resonance fixing device. The magnetic resonance fixing device comprises a mounting plate and is characterized in that a supporting frame is arranged on the mountingplate; a U-shaped connecting seat is arranged at the top of the supporting frame; a screw rod is rotatably connected inside the U-shaped connecting seat; a screw rod sleeve sleeves the screw rod; thescrew rod sleeve is in threaded connection with the screw rod; one end of the screw rod penetrates through the top of the supporting frame and is fixedly connected with a hand ring; two side walls ofthe screw rod sleeve are symmetrically hinged with connecting rods; and the other ends of the connecting rods are respectively hinged with a left arc-shaped block and a right arc-shaped block. The magnetic resonance fixing device has a simple structure and is convenient to operate. The hand ring is rotated to drive the screw rod to rotate, and the screw rod drives the screw rod sleeve to move up and down, so as to drive the connecting rod to open or close the left arc-shaped block and the right arc-shaped block, so that the problem of unstable head fixation in a nuclear magnetic resonance process is solved, ghosting of nuclear magnetic resonance imaging due to head movement is prevented, and accuracy of judgment on patients by doctors is improved.

The invention discloses a magnetic tunnel junction forming method comprising the steps of providing a substrate on which a bottom electrode is formed; and forming a magnetic tunnel junction on the bottom electrode, wherein the magnetic tunnel junction is composed of a first magnetic layer, a tunneling layer and a second magnetic layer sequentially stacked from the bottom up, both the first magnetic layer and the second magnetic layer have vertical anisotropy, when a current from the second magnetic layer to the first magnetic layer exists, the magnetic moment direction of the second magnetic layer is the same as that of the first magnetic layer, and when the direction of the current is opposite, the magnetic moment direction of the second magnetic layer is opposite to that of the first magnetic layer; ferromagnetic particles are injected into the junction of the tunneling layer and the first magnetic layer; and the magnetic moment direction of the ferromagnetic particles is the same asthat of the first magnetic layer. According to the method, the tunneling resistance ratio of the magnetic tunnel junction is improved, the property of the magnetic layer is not changed, and thus thenegative effects are not generated on the other magnetoelectric parameters of the tunnel junction. The invention also discloses a magnetic resistance random access memory.

A data storage system includes a magnetic storage medium and a write head configured to be positioned adjacent the storage medium and. The write head includes a magnetic field source configured to apply a magnetic field to the storage medium and an optical near field coupling structure configured to locally heat the magnetic storage medium with an optical near field proximate the magnetic field applied by the magnetic field source. An overcoat layer on the magnetic storage medium enhances absorption of the optical near field.

A magnetic detector arrangement includes two equally polarised magnets positioned next to each other with the polarisation in the same direction, and a magnetic detector element, wherein the magnets are arranged at a predefined distance apart such that the magnetic field from the magnets will superimpose. A magnetic detector arrangement with an improved tolerance towards deviations in the magnetic field of the comprised permanent magnets can be provided.

The invention relates to a magnetic resonance spectrometer system for realizing clock synchronization of a magnetic resonance spectrometer. The system comprises a clock source module and one or more function modules connected with the clock source module; the clock source module is used for supplying a synchronous clock signal to each function module; and each function module comprises a work clock synchronization sub-module which is used for receiving a synchronous clock signal corresponding to the function module and acquiring one or more work clock signals which are synchronous with the clock source module and have low clock jitter based on the synchronous clock signal. The invention provides a package of solutions for the whole clock synchronization for the spectrometer system, the clock synchronization among the constituent units of the spectrometer system is realized, and the requirement that the constituent units of the spectrometer acquire the clock which is synchronous with the clock signal of the spectrometer clock source unit and has low jitter is met, so that a solid foundation is laid for a spectrometer system to serve magnetic resonance high-quality scanning imaging.

The application discloses a liquid metal sliding bearing, an X-ray tube and a CT scanning device. The liquid metal sliding bearing comprises a rotating core (100), a rotating member (200) capable of rotating relative to the rotating core (100), and liquid metal arranged between the rotating core (100) and the rotating member (200), wherein the rotating member (200) comprises a rotating housing (210) and a rotating flange (220) connected with the rotating housing (210), the rotating housing (210) and the rotating flange (220) are arranged along the axis of the liquid metal sliding bearing, a first sealing structure is formed between the rotating housing (210) and the rotating flange (220), and the first sealing structure comprises a first annular boss (241) formed around the axis of the liquid metal sliding bearing.

In order to accurately measure a gradient magnetic field, a pre-encoding pulse Pk is applied, data S(k, 1)-S(k, T) are collected from an FID signal while applying an encoding pulse Ge having a gradient waveform to be measured, and the above steps are repeated K times with the magnitude of the pre-encoding pulse Pk varied; data D(1,1)-D(1, T-1), D(2, 1)-D(2, T-1), . . . , D(K, 1)-D(K, T-1) having a phase difference DELTAphi as an angle are obtained from the collected data S(1,1)-S(1, T), S(2, 1)-S(2, T), . . . , S(K, 1)-S(K, T); data having corresponding magnitudes of the encoding pulse Ge are added to obtain added data d(1)-d(T-1); gradient magnetic field differences DELTAG(1)-DELTAG(T-1) are obtained from the added data d(1)-d(T-1); and the gradient magnetic field differences DELTAG(1)-DELTAG(T-1) are integrated to obtain a gradient magnetic field G(1)-G(T-1).

The invention provides a control method and a control device of a magnetic resonance system. The control method comprises the following steps: measuring and recording radio frequency field data; obtaining an amplitude estimation value of the radio frequency field based on the radio frequency field data and a particle swarm algorithm; setting an amplitude control parameter of the radio frequency pulse based on the amplitude estimation value; acquiring a setting instruction of the sequence mode of the radio frequency pulse; and outputting a control signal based on the amplitude control parameter and the setting instruction. According to the configuration, on one hand, actual data of the radio frequency field can be found through measurement, on the other hand, the amplitude estimation value of the radio frequency field can be obtained based on the particle swarm optimization, the influence of noise errors is reduced, and the radio frequency amplitude calibration precision and speed are improved. Therefore, the problem that in the prior art, due to the fact that the field intensity of the radio frequency field is affected by various factors, the expected field intensity is changed, and the imaging effect is affected is solved.