33 results about "Longitudinal Relaxation Time" patented technology

In a method for quantitative detection of parameters in MRI, first and second spoiled gradient echo images and at least one multi-echo steady-state first / second magnetization image are acquired; based on the extended phase graph theory, signal equations are obtained corresponding to the first and second spoiled gradient echo images, the at least one multi-echo steady-state first magnetization image and the at least one multi-echo steady-state second magnetization image; based on the signal equations of the first and second spoiled gradient echo images, the signal equation of the at least one multi-echo steady-state first magnetization image and the signal equation of the at least one multi-echo steady-state second magnetization image, a spoiled gradient echo proton density map, a multi-echo steady-state proton density map, a longitudinal relaxation time map and a transverse relaxation time map of the target tissue are obtained.

The invention provides a relaxation time measuring method and system. The relaxation time measuring method comprises the following steps: heating an atomic gas chamber to be measured to a set working temperature, and applying a static magnetic field in a z direction to the atomic gas chamber to be measured; starting the pumping laser light source and the detection laser light source, and performing light path alignment adjustment; the pumping laser light source is used for polarizing alkali metal atoms in the atomic gas chamber to be measured; determining a relaxation time measurement mode according to a relaxation time measurement requirement, triggering a corresponding operation, and collecting a corresponding relaxation signal; the measurement mode comprises at least one of the following modes: an alkali metal electron spin transverse relaxation mode, an alkali metal electron spin longitudinal relaxation mode, an inert gas nucleon spin transverse relaxation mode and an inert gas nucleon spin longitudinal relaxation mode; and fitting the relaxation signal corresponding to the mode to obtain a corresponding relaxation time value. According to the invention, the transverse and longitudinal relaxation time of alkali metal electrons and the transverse and longitudinal relaxation time of inert gas nucleons can be measured on the same machine.

The invention belongs to the technical field of geophysical exploration, and relates to an underground water magnetic resonance longitudinal relaxation time detection method, which comprises the following steps: laying a magnetic resonance detection coil on the ground, fixing a short emission time, changing a current amplitude, emitting a plurality of short pulses, and collecting a short pulse observation signal generated by each short pulse; fixing a long emission time, re-emitting a series of long pulses with different current amplitudes, and collecting a long pulse observation signal generated by each long pulse; inverting the short pulse observation signal to obtain water content and transverse relaxation time distribution of underground water at different depths; and taking the water content and the transverse relaxation time distribution of the underground water at different depths as prior data of Bayesian inversion, and analyzing the long pulse observation signal by adopting Bayesian inversion to obtain longitudinal relaxation time distribution. According to the invention, a complex excitation sequence form is not needed, and a longitudinal relaxation signal of a short relaxation sample with a fast attenuation speed can be captured. The method is suitable for a high-power scene of field ground magnetic resonance detection.

A method, CRM and system for determining a cardiomyocyte manganese ion uptake rate constant in one or more regions of interest in a heart of a subject comprising: a providing step comprising: providing a left ventricular myocardial image slice covering one or more regions of interest taken during a first time period; providing one or more longitudinal relaxation time weighted images of the left ventricular blood pool taken during the first time period to measure an average signal intensity in blood during the first time period; providing a hematocrit measurement; providing an extracellular volume measurement for each of the one or more regions of interest; an administration step comprising administering a contrast agent comprising manganese 2+ ions; an image acquisition step comprising: performing image acquisition of the left ventricular blood pool using a longitudinal relaxation time weighted pulse sequence at a plurality of time intervals during a second time period to measure respective signal intensities in blood at the plurality of time intervals; performing a longitudinal relaxation time map image acquisition of a left ventricular myocardial image slice covering the one or more regions of interest during a third time period; a measurement step comprising measuring a signal intensity in blood at each of the plurality of time intervals using an image taken at a time point within said corresponding time interval; and a calculation step comprising: calculating a change in a myocardial longitudinal relaxation rate for each region of interest from a baseline myocardial longitudinal relaxation rate extracted from the myocardial image slice taken during the first time period and a myocardial longitudinal relaxation rate at an end time point of an MRI examination extracted from the myocardial image slice during the third time period; calculating a blood longitudinal relaxation rate for each of the plurality of time intervals using respective signal intensities in blood at the plurality of time intervals and a relationship between signal intensity and said plurality of relaxation rates using the integral over all the changes in blood longitudinal relaxation rate in conjunction with the myocardial longitudinal relaxation rate at the end time point in a proportionality relationship with a cardiomyocyte Mn2+ uptake rate constant to estimate the cardiomyocyte Mn2+ uptake rate constant for each of the one or more regions of interest; wherein said first time period is before an administration of the contrast agent, said second time period is during and after an administration of the contrast agent, and said third time period encompasses the end timepoint of an MRI examination.

The invention relates to a longitudinal relaxation time calculation method, nuclear magnetic resonance imaging equipment and a storage medium, and the method comprises the steps: executing a pulse sequence, and collecting a first multi-echo signal; the pulse sequence comprises a radio frequency pulse and a readout gradient, and the radio frequency pulse comprises a first excitation pulse and a plurality of second excitation pulses in a repetition time of the pulse sequence; the first multi-echo signal is a multi-echo signal acquired after executing a second excitation pulse; performing image reconstruction on the first multi-echo signal to obtain a multi-echo image; calculating target signal intensity according to a signal attenuation function and the information of the multi-echo image; and calculating the longitudinal relaxation time according to the target signal intensities of the plurality of repetition times. According to the invention, after a small number of first excitation pulses are applied, accurate longitudinal relaxation time distribution is obtained, and the problem of low calculation efficiency in the prior art is solved.

A method for generating a characteristic representation of a substance is described. The method comprises: obtaining one or more portions of nuclear magnetic resonance (NMR) data of the substance, wherein each NMR data portion comprises one or more NMR data sets each comprising intensity data and relaxation data, processing each NMR data portion(s) into a multidimensional distribution of fitted data sets by performing multiple fittings to a function, wherein the function comprises at least 3 fitting parameter(s), and generating the characteristic representation of the substance from the fitted data sets. The processing comprises applying at least one start guess. Each fitted data set comprises data embedding at least one fitted data subset comprising an apparent longitudinal relaxation time (T1*), an associated apparent transverse relaxation time (T2*), and an associated intensity (M0), preferably the function is a function which represents a model of the obtained NMR data portion(s).

The present application relates to a kind of cardiac magnetic resonance longitudinal relaxation time measurement method, medium and equipment.The measurement method includes the following steps: S1 uses MOLLI sequence respectively before and after scanning contrast;Specifically, in the before and after scanning contrast, by setting different initial inversion time TI, setting 3 groups of LL experiment LL1, LL2, LL3 triggered by continuous ECG, enough relaxation curve sampling points are obtained after fusion;And data is collected at the end of diastole of cardiac cycle, and 1 image is obtained per heartbeat;S2 image processing.This measurement method can realize single-pixel high-resolution T1 mapping under the breath holding of selection data acquisition and multi-LL experiment data fusion, give consideration to high accuracy, high resolution and high efficiency, and have good compatibility and practicality, provide new scheme for early diagnosis of heart disease, lesion quantification and prognosis evaluation, have wide clinical application prospect.

The invention provides a multiphase flow phase volume fraction detection method, system and device, and belongs to the technical field of multiphase flow metering. The multiphase flow phase volume fraction detection method comprises the following steps: acquiring the flow velocity of a fluid in a flowing state, the real-time fluid liquid phase moisture content and the fluid liquid phase oil content; based on preset scale information, the flowing speed and the real-time fluid liquid-phase water content, the multiphase flow gas volume content is obtained through calculation; wherein the preset scale information comprises the magnetization vector of the pure oil fluid, the magnetization vector of the pure water fluid, the longitudinal relaxation time of the pure oil fluid and the longitudinal relaxation time of the pure water fluid; and obtaining a multiphase flow phase volume fraction detection result based on the multiphase flow gas volume content, the real-time fluid liquid phase moisture content and the fluid liquid phase oil content. The three-phase volume fraction of oil, gas and water in the fluid can be detected in real time, so that the requirement of an oil well on real-time on-line metering of the flow of each phase of the fluid is met. And the detection accuracy of the phase volume fraction of the multiphase flow is improved.

The present invention belongs to the field of geophysical exploration technology and is a method for detecting the longitudinal relaxation time of groundwater using magnetic resonance. The method comprises: laying a magnetic resonance detection coil on the ground, fixing a short emission time, varying the current amplitude to emit multiple short pulses, and collecting the short pulse observation signal generated by each short pulse; fixing a long emission time, re-emitting a series of long pulses with different current amplitudes, and collecting the long pulse observation signal generated by each long pulse; inverting the short pulse observation signal to obtain the water content and transverse relaxation time distribution of groundwater at different depths; using the water content and transverse relaxation time distribution of groundwater at different depths as prior data for Bayesian inversion, and employing Bayesian inversion to analyze the long pulse observation signal to obtain the longitudinal relaxation time distribution. The present invention can capture the longitudinal relaxation signal of samples with fast decay rates and short relaxation without the need for complex excitation sequences. The method is suitable for high-power scenarios in field ground magnetic resonance detection.

The invention discloses a low-field NMR relaxation time rapid measurement method, and the method comprises the steps: designing an IR-bSSFP pulse sequence which comprises a 180-degree reversal pulse and an excitation pulse sequence, and enabling the flip angle of a radio frequency excitation pulse in the excitation pulse sequence to be a pseudo-random flip angle; the radio-frequency phases of the adjacent radio-frequency excitation pulses are linearly changed by a fixed phase increment; based on the IR-bSSFP pulse sequence, obtaining a component MRF signal sequence of a measured object, and simulating a magnetization vector evolution process to obtain a dictionary matrix; matching the component MRF signal with a dictionary matrix pattern in combination with a smooth constraint term to obtain corresponding longitudinal relaxation time and transverse relaxation time; the invention also discloses low-field NMR relaxation time rapid measurement equipment, which comprises a pulse sequence construction module, a dictionary generation module and a mode matching module. Multi-parameter information can be obtained through single scanning, the measurement time is remarkably shortened, the experiment complexity is reduced, and the precision and repeatability of a measurement result are improved.

The invention relates to the technical field of geological exploration, in particular to a dessert interval determination method and device, a storage medium and a computer program.The method comprises the steps that distribution information of one-dimensional nuclear magnetic transverse relaxation time T2 and distribution information of longitudinal relaxation time T1 of rock samples of different depths of a continental facies shale oil and gas reservoir are obtained, sorting the distribution information of the transverse relaxation time T2 and the distribution information of the longitudinal relaxation time T1 of each rock sample along the corresponding depth of each rock sample to obtain pore size distribution information and oil-water distribution information of the continental facies shale oil and gas reservoir; and determining the sweet spot interval of the continental facies shale oil and gas reservoir according to the pore size distribution information and the oil-water distribution information. According to the method and the device, the oil content conditions of the reservoirs can be compared more visually, and the dividing efficiency and accuracy of the dessert layer sections are improved.

A method for generating a property representation of a substance is described. The method comprises: obtaining portions of one or more nuclear magnetic resonance (NMR) data of the substance, where each NMR data portion comprises one or more NMR datasets, each NMR dataset comprising intensity data and relaxation data; processing each NMR data portion into a multi-dimensional distribution of a fitting data set by performing a plurality of fits of a function, where the function includes at least 3 fitting parameters; and generating a characteristic representation of the substance from the fitting data set. The processing includes applying at least one initial guess value. Each set of fitting data comprises data embedded with at least one subset of fitting data comprising an apparent longitudinal relaxation time (T1 *), an associated apparent transverse relaxation time (T2 *) and an associated intensity (M0), preferably said function being a function of a model representing the obtained NMR data portion.

The invention provides a magnetic resonance parameter determination method and device, electronic equipment and a computer program product, and the method comprises the steps: scanning a scanning object through employing a plurality of gradient echo sequences of different repetition times, and obtaining a magnetic resonance image corresponding to the gradient echo sequence of each repetition time; the radio frequency flip angles set by the plurality of gradient echo sequences are the same; performing nonlinear fitting according to a plurality of different repetition times, a radio frequency flip angle set by the gradient echo sequence, the signal intensity of each magnetic resonance image and a preset signal model to determine a longitudinal relaxation time constant, the independent variables of the signal model including the repetition time and the longitudinal relaxation time constant, the dependent variable of the signal model is the signal intensity of the magnetic resonance image. Therefore, the gradient echo sequences with the same flip angle and different repetition times are adopted for scanning, and nonlinear fitting is performed based on the steady-state signal model, so that the longitudinal relaxation time constant can be quickly and accurately determined without long waiting time.

The invention belongs to the technical field of nuclear magnetic resonance gyroscopes, and relates to a device and a method for measuring longitudinal relaxation time of a miniaturized atomic air chamber. The measuring device comprises: a miniaturized atomic gas cell; the pumping light and light path structure comprises a pumping light laser, a pumping light polarizer, a quarter-wave plate and a light absorption black body which are sequentially arranged along the Z axis; the detection light and light path structure comprises a detection light laser, a detection light polarizer, a half-wave plate, a first right-angle prism reflector, a second right-angle prism reflector, a polarization splitting prism, a first photoelectric detector and a second photoelectric detector which are sequentially arranged along a detection light path; the temperature control system comprises non-magnetic heating devices arranged on the two sides of the miniaturized atomic gas chamber and a temperature control circuit; the magnetic field control system comprises a double-layer magnetic shielding cover, a three-axis magnetic field coil arranged on the outer side of the miniaturized atomic gas chamber, and a magnetic field control circuit; and the signal processing system performs fitting calculation on the longitudinal relaxation time.

The invention relates to a magnetic resonance longitudinal relaxation time measuring method and system. The method comprises the following steps: acquiring minimum magnetic resonance signal values and other magnetic resonance signal values at each pixel position in magnetic resonance images at a plurality of acquisition moments; fitting the minimum magnetic resonance signal value at each pixel position and other magnetic resonance signal values to obtain a first fitting result of each pixel position; and fitting the opposite number of the minimum magnetic resonance signal value at each pixel position and other magnetic resonance signal values to obtain a second fitting result of each pixel position, and determining a magnetic resonance longitudinal relaxation time measurement result according to the first fitting result and the second fitting result of each pixel position. By adopting the method, the measurement result of the magnetic resonance longitudinal relaxation time can be accurately obtained.

The invention provides a shale oil reservoir pore structure correction method and device, equipment and a medium. The method comprises the following steps: performing nuclear magnetic resonance test on first shale to obtain a one-dimensional nuclear magnetic T2 spectrum and a two-dimensional nuclear magnetic T1-T2 spectrum of the first shale; t1 represents longitudinal relaxation time, and T2 represents transverse relaxation time; identifying the one-dimensional nuclear magnetic T2 spectrum to obtain a first signal amplitude of the first shale; identifying the two-dimensional nuclear magnetic T1-T2 spectrum to obtain a second signal amplitude of the first shale; establishing an incidence relation between the first signal amplitude and the second signal amplitude; the association relationship is used for determining an amplitude conversion relationship between a one-dimensional nuclear magnetic T2 spectrum and a two-dimensional nuclear magnetic T1-T2 spectrum corresponding to the skeleton signal of the first shale; and correcting the pore structure of the target to-be-corrected shale based on the amplitude conversion relation and the one-dimensional nuclear magnetic T2 spectrum and the two-dimensional nuclear magnetic T1-T2 spectrum of the target to-be-corrected shale in the saturated state. Therefore, the nuclear magnetic porosity and pore size distribution of the shale oil reservoir can be accurately determined.

The invention discloses a high-precision rapid in-situ measurement device and method for polarization parameters of an atomic common magnetometer, and belongs to the technical field of quantum precision measurement and ultrahigh-sensitivity inertial measurement. Based on an atom manipulation technology, a transverse modulation magnetic field is applied to an atom ensemble through a three-axis magnetic field coil, a lock-in amplifier is adopted to extract device output phase frequency response, a longitudinal axis magnetic field is gradually scanned until the minimum phase frequency response is obtained, and therefore a nuclear spin polarization equivalent magnetic field and an electron spin polarization equivalent magnetic field are obtained. And further obtaining the electron spin polarizability, the nuclear spin polarizability and the nuclear spin longitudinal relaxation time. According to the invention, the rapid in-situ measurement of the atom ensemble polarization parameters of the SERF gyroscope is realized, and the measurement precision is improved.

The application provides a shale oil reservoir pore structure correction method, device, equipment and medium; relates to the pore structure correction technical field, and the method comprises the steps of: carrying out nuclear magnetic resonance test on the first shale to obtain one-dimensional nuclear magnetic T2 spectrum and two-dimensional nuclear magnetic T1-T2 spectrum of the first shale; T1 represents longitudinal relaxation time, and T2 represents transverse relaxation time; identifying the one-dimensional nuclear magnetic T2 spectrum to obtain the first signal amplitude of the first shale; identifying the two-dimensional nuclear magnetic T1-T2 spectrum to obtain the second signal amplitude of the first shale; the correlation between the first signal amplitude and the second signal amplitude is established; the correlation is used to determine the amplitude conversion relationship of the one-dimensional nuclear magnetic T2 spectrum and the two-dimensional nuclear magnetic T1-T2 spectrum corresponding to the skeleton signal of the first shale; based on the amplitude conversion relationship, the one-dimensional nuclear magnetic T2 spectrum and the two-dimensional nuclear magnetic T1-T2 spectrum of the target shale under the saturated state, the pore structure of the target shale to be corrected is corrected. In this way, the nuclear magnetic porosity and pore size distribution of the shale oil reservoir can be accurately determined.

To provide a highly polarized object containing a molecule, the target of high polarization by triplet DNP, to which a polarization source can be added and in which a sufficient longitudinal relaxation time can be achieved, and a manufacturing method thereof, a high polarization method and a high polarization device.SOLUTION: A highly polarized object 100 includes a first molecule 102, a second molecule 104, and a polarization source 108, where at least one of the first molecule and the second molecule is a target molecule whose nuclear spin is to be highly polarized by triplet DNP, a molecule that is not the target molecule out of the first molecule and the second molecule is a coformer molecule, the first molecule and the second molecule comprise a co-crystalline crystal structure including a binding part 106, the supramolecular synthon with a hexagonal structure, and the polarization source is arranged at a position to displace a part of the crystal structure.SELECTED DRAWING: Figure 1

The invention relates to a longitudinal relaxation time constant determination method and device and magnetic resonance imaging equipment, and the method comprises the steps: obtaining a plurality of first amplitude images corresponding to a plurality of inversion recovery moments; wherein the sizes of the plurality of first amplitude images are the same; determining an amplitude image with the minimum amplitude at a preset target position point in the plurality of first amplitude images as a target amplitude image; selecting an image except the target amplitude image in the plurality of first amplitude images as a second amplitude image; and determining a longitudinal relaxation time constant of the target position point according to the second amplitude image. According to the invention, the problem of inaccurate calculation of the longitudinal relaxation time constant in the prior art is solved.

Systems and method for nuclear magnetic resonance (NMR) well logging use an inversion pulse sequence with a Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence to improve spin magnetization calculations. Improved Bloch equation-based calculations consider conditions where a longitudinal relaxation time and a transverse relaxation time of the hydrogen nuclei (e.g., of a subterranean hydrocarbon pool and / or water) are within an order of magnitude of pulse durations for the inversion pulse sequence and the CPMG pulse sequence. Accordingly, an NMR response to the inversion pulse sequence and the CPMG pulse can be detected and used to calculate one or more spin magnetization values with higher accuracy amplitudes. Reservoir characteristics are determined based on the one or more spin magnetization values. As such, improved well operations (e.g., selecting a drilling site, determining a drilling depth, and the like) can be performed.

The invention relates to the technical field of magnetic resonance imaging, and provides an ASL perfusion imaging method, device and system based on multi-parameter magnetic resonance measurement, and the method comprises the steps: determining a first parameter based on first magnetic resonance measurement data, determining a second parameter based on second magnetic resonance measurement data, and determining a third parameter based on third magnetic resonance measurement data, and determining mark delay time of ASL perfusion imaging based on the first parameter, the second parameter and the third parameter, and performing ASL perfusion imaging based on the mark delay time. Wherein the first parameter comprises blood vessel path length information, the second parameter comprises blood flow velocity information, and the third parameter comprises blood longitudinal relaxation time. Examination time does not need to be prolonged, and more appropriate marking delay time can be matched for different subjects so as to improve the accuracy of examination results.

The application discloses an optimization method, device, equipment and medium for magnetic resonance imaging, and relates to the field of magnetic resonance imaging. The method comprises the following steps: acquiring a reference longitudinal relaxation time of an imaging magnetic resonance device with a preset main magnetic field strength; constructing a linkage fitting function between TR and TI parameters based on the reference longitudinal relaxation time, taking the maximum difference value between an image signal of a hemorrhagic focus and an image signal of healthy brain parenchyma as a target; determining a target TI according to a target TR and the linkage fitting function; optimizing scanning parameters of the magnetic resonance device by using a minimum effective echo time, the target TR and the target TI; acquiring an initial magnetic resonance image, which is obtained by scanning a stroke patient by using the magnetic resonance device with the optimized parameters; and enhancing the initial magnetic resonance image by using a nonlinear stretching function to obtain a stroke triage enhanced inversion recovery image. The application can improve the image contrast of the magnetic resonance imaging.

The invention discloses an extraocular muscle extracellular volume measurement system and method based on magnetic resonance imaging, and relates to the technical field of medical image processing and quantitative measurement, and the technical key points are as follows: obtaining enhanced T1mapping sequence horizontal axial image data comprising extraocular muscle after plain scanning and 10 minutes delay through MRI equipment; a region of interest used for calculating a T1 value is obtained on the extraocular muscle T1mapping image; calculating the longitudinal relaxation time (T1 value) of each pixel of the extraocular muscle based on the T1mapping sequence; the extracellular volume (ECV) is calculated through a formula according to the blood T1 value and the hematocrit parameter; and constructing an extraocular muscle three-dimensional model and visualizing ECV distribution. The method has the effects of breaking through the invasive limitation of traditional biopsy, accurately quantifying the extracellular volume of the extraocular muscle, and providing an important basis for diagnosing ocular muscle fibrosis, inflammatory pseudotumor, thyroid-related eye diseases and the like.

The application relates to the technical field of magnetic resonance imaging, and provides an ASL perfusion imaging method, device and system based on multi-parameter magnetic resonance measurement, which comprises the following steps: determining a first parameter based on first magnetic resonance measurement data; determining a second parameter based on second magnetic resonance measurement data; determining a third parameter based on third magnetic resonance measurement data; determining a labeling delay time of ASL perfusion imaging based on the first parameter, the second parameter and the third parameter; and performing ASL perfusion imaging based on the labeling delay time. The first parameter comprises blood vessel path length information, the second parameter comprises blood flow velocity information, and the third parameter comprises blood longitudinal relaxation time. The application does not need to prolong the examination time, can match more suitable labeling delay time for different subjects, and improves the accuracy of the examination result.

Provided in embodiments of the present invention are a body mold, a magnetic resonance imaging system, and a main magnetic field evaluation method and a gradient field evaluation method therefor. The body mold comprises a plurality of substrates, wherein the plurality of substrates are sequentially arranged to form a multi-layer structure in a three-dimensional space. Each substrate is provided with a plurality of first accommodation bodies for accommodating first resonant volumes and a plurality of second accommodation bodies for accommodating second resonant volumes. The plurality of first accommodation bodies and the plurality of second accommodation bodies are arranged at intervals. The first resonant volumes and the second resonant volumes have different longitudinal relaxation times T1.

The invention discloses a living cell carried multi-nuclear magnetic resonance probe delivery system as well as preparation and application thereof, a multi-nuclear magnetic resonance probe is of a core-shell structure, a polylactic acid-glycolic acid copolymer is taken as a shell, and a compound formed by perfluorocrown ether, paramagnetic metal ions and a fluorine chelating agent is taken as a core. The preparation process of the nanoprobe is simple and convenient, the nanoprobe has good biological safety and 19F magnetic resonance imaging (19F MRI) effect, meanwhile, the nanoprobe has short longitudinal relaxation time T1, and the 19F MRI sensitivity in unit sampling time can be improved. The probe is coupled to a macrophage membrane, and active targeting enrichment of a tumor part is realized by utilizing the homing ability of macrophages to tumors, so that the probe can be used as a living cell 19F MRI probe and has good medical research and application prospects.

The invention discloses a method for determining diffusion speed control steps of sodium ions in hard carbon and optimizing a microstructure. According to the method, longitudinal relaxation time T1 values of 23Na are measured under different potentials (0.3, 0.1, 0.05 and 0 V), migration behaviors of adsorbed sodium and intercalated sodium (NaCx) are distinguished, a diffusion coefficient curve is obtained by combining GITT, and dominant steps of limiting overall diffusion are judged; and dynamic collaborative optimization under the conditions of low temperature and large current is realized by selecting a cross-linking agent and adjusting a carbonization system and pore engineering. The reversible capacity of the optimized hard carbon at 25 DEG C and 5 DEG C can be greater than or equal to 297 mAh g <-1 >, and the capacity retention rate at-40 DEG C and 30 mA g <-1 > is greater than or equal to 86%. The method is suitable for various carbon sources, and a closed-loop path of NMR dynamic recognition, speed control judgment, structural regulation and electrochemical verification can be formed.

The embodiment of the present invention discloses a method, device, electronic device and medium for determining the closing time of the blood-brain barrier, wherein the method comprises: in the process of opening the blood-brain barrier of the target brain area of ​​the target object by magnetic resonance-guided ultrasound, respectively obtaining the magnetic resonance longitudinal relaxation time spectrum corresponding to multiple contrast agent injection moments of the target brain area, determining the blood-brain barrier opening area of ​​the target brain area, the muscle tissue area corresponding to the blood-brain barrier opening area and the blood-brain barrier closing area; for each magnetic resonance longitudinal relaxation time spectrum, respectively determining the magnetic resonance longitudinal relaxation time of the blood-brain barrier opening area, the muscle tissue area and the blood-brain barrier closing area; determining the contrast agent concentration of each area based on the magnetic resonance longitudinal relaxation time of each area; determining the closing time of the blood-brain barrier opening area according to the contrast agent concentration of each area corresponding to multiple injection moments. The prediction of the blood-brain barrier opening recovery time is realized.

The invention relates to a transformer oil relaxation self-adaptive detection method and system based on nuclear magnetic resonance, and the method comprises the steps: carrying out the optimization measurement process of transverse relaxation time T2: carrying out the measurement of the transverse relaxation time T2 through employing a CPMG pulse sequence based on a low-field nuclear magnetic resonance system, and collecting a CPMG echo signal in the T2 measurement process; performing Laplace inversion to obtain transverse relaxation time T2 distribution and a maximum T2 component of the transformer oil, and optimizing the number of echoes on the basis of the maximum T2 component; and an optimized measurement process of longitudinal relaxation time T1: based on a low-field nuclear magnetic resonance system, carrying out longitudinal relaxation time T1 measurement by adopting an inversion recovery sequence, carrying out Laplace inversion on multiple groups of collected inversion recovery signals to obtain a maximum T1 component, determining optimal waiting time by taking the maximum T1 component as a reference value, and finally determining an optimal pulse sequence parameter. Compared with the prior art, the method has the advantages of improving the detection precision and efficiency and the like.