19 results about "Longitudinal Relaxation Time" patented technology

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 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.

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 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 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.

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 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 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 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.

The invention discloses a method and a device for determining a flow velocity metering upper limit of a magnetic resonance flowmeter. The method comprises the following steps: acquiring field intensity distribution data of a plurality of measurement points of the magnetic resonance flowmeter from the starting position of a probe to the center of an antenna, and acquiring the maximum amplitude of an echo signal and the maximum amplitude of noise measured by putting the probe into static pure water; based on the field intensity distribution data and the maximum amplitude of the echo signal, determining a first magnetization vector when the fluid flows to the antenna according to the set flow velocity and the longitudinal relaxation time of the measured fluid; according to the first magnetization vector and the longitudinal relaxation time of the fluid, determining a second magnetization vector attenuating for a set time after the fluid reaches the antenna; whether the difference value between the second magnetization vector and the maximum amplitude of the double noise is smaller than a set difference value or not is judged; if yes, determining the current speed as the upper limit of the flow velocity measurement of the flow meter on the fluid; and if not, modifying the current speed. According to the method, the measurable flow velocity upper limit of the magnetic resonance flowmeter facing different working conditions can be conveniently determined.

The invention provides a methane occurrence state quantitative analysis method for accurate resource evaluation of deep coal bed gas, which comprises the following steps: firstly, collecting a two-dimensional nuclear magnetic resonance spectrogram of a coal sample adsorption test, carrying out gridding processing on two-dimensional nuclear magnetic resonance spectrogram data of the coal sample adsorption test, and establishing a two-dimensional signal matrix; then, according to the distribution characteristics of the longitudinal relaxation time T1 and the transverse relaxation time T2, dividing the spectrogram into four regions, namely a single-layer adsorption state, a filling adsorption state, an inter-pore free state and an inter-cavity free state; and finally, carrying out point-by-point summation on the signals of each region, and converting a value obtained after signal intensity summation into a gas content model so as to obtain the quantitative content of methane in different occurrence states. According to the method, clear distinguishing between single-layer adsorption and filling adsorption can be achieved, the law that the occurrence state of adsorption and free methane evolves along with pressure can be revealed, and the technical problem of accurately determining the in-situ occurrence state of deep coal bed gas, which puzzles the deep coal bed gas industry for a long time, is solved.

The invention relates to a longitudinal relaxation time constant acquisition method and device and a magnetic resonance imaging system. The method comprises the following steps: acquiring a plurality of amplitude images corresponding to a plurality of inversion recovery moments; adjusting the plurality of amplitude images according to a first deviation value of the amplitude in each amplitude image; and obtaining a longitudinal relaxation time constant of a target position point in the amplitude image according to the multiple adjusted amplitude images and the corresponding inversion recovery moments. By adopting the method, the problem of low accuracy of a longitudinal relaxation time constant fitting result can be solved.