143 results about "Relaxation (NMR)" patented technology

The invention discloses an SERF atom magnetometer double-axis magnetic field detection method and device based on pulsed magnetic field modulation, relates to the technical field of magnetic field precision measurement, and compresses the action time of a modulation magnetic field additionally applied in the same unit period on a hot atom ensemble by replacing conventional continuous sinusoidal magnetic field modulation with pulsed magnetic field modulation. The pulse magnetic field with the duty ratio of d can reduce the spin exchange relaxation rate to 2d times of that of a conventional method under the same modulation amplitude and frequency, due to the fact that the spin exchange relaxation rate is effectively restrained, the collected polarizability response signal is obviously improved, and the polarizability response signal can be obtained through the pulse magnetic field with the duty ratio of d and the pulse magnetic field with the duty ratio of d. Low-relaxation-rate sensitivity-enhanced double-axis magnetic field measurement under a pulse modulation scheme is realized, the double-axis measurement sensitivity of a miniaturized SERF atom magnetometer is further improved, and the method has great significance in supporting leap-type development of a future array type extremely-weak magnetic imaging system and medical application thereof.

The invention discloses a magnetic source positioning method based on a spin-exchange relaxation-free atom magnetometer, and aims to provide a high-precision brand-new solution for magnetic source positioning in a near-zero magnetic environment by performing physical modeling and least square estimation on space magnetic field distribution of a target magnetic source. The magnetometer is enabled to be simultaneously sensitive to a three-axis magnetic field, a light absorption detection method is utilized to ensure that complete three-axis magnetic field information is obtained, and the sensitivity of the three axes reaches fT / Hz1 / 2 (1fT = 10 <-15 > T) magnitude. In the positioning process, the target magnetic source is abstracted into a physical model of the magnetic dipole, and the space magnetic field information generated by the target magnetic source is obtained through the atom magnetometer, so that the long-term stability of the magnetic source positioning process and the high precision of the positioning result can be ensured in the zero magnetic environment; therefore, a high-precision magnetic positioning technical means with great potential is provided for various application scenes such as paleomagnetic sample testing and magnetic source positioning in medical research, and technical progress and application expansion in related fields are expected to be promoted.

The invention belongs to the technical field related to nanometer material testing, and discloses a magnetic nanoparticle relaxation time detection method and an environmental parameter detection method, and the method comprises the following steps: applying an excitation magnetic field around a to-be-detected target mixed with magnetic nanoparticles; obtaining magnetization response generated by the magnetic nanoparticles in any direction of the magnetic field plane, and obtaining phase lag corresponding to any order harmonic term of the magnetization response; according to the function relationship between the phase lag corresponding to any harmonic term and the Brown relaxation time of the magnetic nanoparticles, solving and obtaining the Brown relaxation time of the magnetic nanoparticles; wherein the function relationship comprises a correction term introduced by magnetic dipole interaction of the magnetic nanoparticles. The magnetic dipole interaction among the magnetic nanoparticles is introduced, relaxation time detection of particle space distribution under an external magnetic field is corrected, the interference of the magnetic dipole interaction on the magnetic nanoparticle Brown relaxation time detection process can be effectively reduced, and accurate estimation of the magnetic nanoparticle Brown relaxation time is realized.

The present invention comprises a method for jointly processing data from the nuclear magnetic resonant (NMR) response of oil and rock samples in in natura condition, and its main product is the delimitation of the oil saturation (So) present in the rock samples, i.e., the determination of the range of admissible values of the volumetric fraction of the porous volume of the rock occupied by such fluid. The method requires a small volume of oil, originating from or of a composition similar to the oil present in the rock being tested, since it is based on both the measurement of the NMR response of the rock sample and the response of the fluid sample. These two sets of data feed a statistical inference scheme that (1) determines a range of admissible values for the So of the sample, delimited by the minimum and maximum oil saturation values compatible with the two sets of data presented; (2) produces, for each of these extreme values of admissible So, a decomposition of the rock relaxation time spectrum into two complementary spectra, the first highlighting the signatures relating to oil and the second comprising the distribution of the rock relaxometric signatures that cannot correspond to such fluid under the prescribed saturation condition.

The invention belongs to the technical field of oil and gas reservoir engineering and multiphase seepage dynamic monitoring, relates to a characterization method of seepage behaviors of multiphase fluid in a porous medium, and particularly provides a dynamic construction method of a multiphase displacement capillary pressure-saturation relationship based on nuclear magnetic resonance. Comprising the following steps: S1, acquiring a low-field nuclear magnetic resonance relaxation spectrum of a porous medium in a gas-water two-phase displacement process; s2, determining two-phase fluid interfacial tension, a wetting contact angle and a rock surface relaxation rate; s3, determining the dynamic cut-off relaxation time of the displacement stage; s4, calculating equivalent capillary pressure; the residual water saturation is calculated, and the equivalent capillary pressure is the capillary pressure corresponding to the current displacement stage and is used for constructing a capillary pressure-saturation curve. According to the method, the capillary pressure change in the porous medium can be obtained only through spectral analysis without a centrifugal or mercury injection experiment.

The invention relates to the technical field of nuclear magnetic resonance logging, aims to solve the problem that a method for jointly correcting a nuclear magnetic resonance logging T2 spectrum by integrating multiple factors does not exist at present, and provides a gas-containing shale nuclear magnetic resonance relaxation time spectrum correction method, a storage medium and a device. The method comprises the steps of obtaining target layer information; determining a T2 spectrum correction position; factors influencing the difference between the nuclear magnetic porosity and the conventional logging porosity are analyzed, and the influence of the factors on the nuclear magnetic resonance logging T2 spectrum is corrected according to the factors; respectively fitting each spectrum peak of the T2 spectrum through a Gaussian distribution curve, completing correction of each factor on the spectrum peak, and obtaining a final corrected nuclear magnetic offset T2 spectrum; superposing the porosity components of the corrected T2 spectrum Gaussian distributions of the fluid peaks at the corresponding distribution points to obtain corrected effective porosity and total porosity; according to the invention, automatic correction of the nuclear magnetic resonance logging T2 spectrum can be realized.

The invention belongs to the technical field of cerium-based rare earth oxide dispersibility testing, and particularly relates to a method for evaluating cerium-based rare earth oxide particle surface characteristics and slurry dispersion stability. Comprising the following steps: when cerium-based rare earth oxide particles are synthesized, adding a paramagnetic element as a probe, and mixing the synthesized particles with a dispersing agent and water to obtain mixed slurry; nuclear magnetic resonance scanning is adopted, the body water relaxation peak and the particle surface bound water and body water exchange dynamic relaxation peak of the mixed slurry in each stage of the process from uniform mixing to standing layering are measured, and the particle surface characteristics are evaluated based on the relaxation efficiency; meanwhile, a linear relation between the relaxation peak area proportion and the sedimentation time in the standing layering process is constructed, a fitting slope value is obtained, and the dispersion stability of the mixed slurry is evaluated. According to the method, non-intrusive in-situ detection of the dispersion stability of the cerium-based rare earth oxide particle slurry is realized by innovatively using a low-field nuclear magnetic resonance mode, and accurate comparison and evaluation of the dispersion stability can be realized.

The invention relates to a special device and method for calibrating a relaxation time measurement result of a medical magnetic resonance imaging (MRI) system. The special device comprises a relaxation time standard die body, an optical fiber temperature measurement system and a control computer. The relaxation time standard die body is composed of a die body shell, a sealing cover and a relaxation time standard unit. The relaxation time standard unit is composed of reagent bottles, and the optical fiber temperature measuring probe is inserted into the relaxation time standard die body. According to the method, T1 and T2 standard values of a relaxation time standard substance under different static magnetic field intensities are calibrated by using a magnetic resonance spectroscopy method, and a relaxation time measurement result of an MRI system is calibrated by using the calibrated relaxation time standard substance. And adopting a reversal recovery sequence to calibrate T1, and adopting a CPMG sequence to calibrate T2. The device and the method can be used for calibrating the relaxation time measurement result of the MRI system, so that the accuracy and the consistency can be improved, and the clinical application is promoted.

The embodiment of the invention discloses a method and device for testing foam seepage characteristics of a heterogeneous porous medium, electronic equipment and a storage medium, and relates to the technical field of fluid mechanics and nuclear magnetic resonance. The method comprises the steps that a heterogeneous porous medium sample with a clear permeability level difference is prepared, and the permeability level difference of the heterogeneous porous medium sample is determined; setting test parameters according to the permeability level difference of the sample, calibrating imaging parameters of the low-field nuclear magnetic resonance equipment, and setting a weighting mode; performing foam flooding treatment on the sample according to the set injection parameters, acquiring a spectrum of the sample according to the test parameters when foam is injected into a set amount, and acquiring nuclear magnetic imaging of the sample through low-field nuclear magnetic resonance equipment according to imaging parameters and a weighting mode; according to the relaxation characteristic of the spectrum, the main peak endpoint value is used for dividing the pore channel, the foam sweep degree is calculated according to the spectrum peak area of the spectrum, and the foam plugging strength is calculated according to the signal amplitude of nuclear magnetic imaging. According to the method, the problems of poor visualization adaptability and lack of evaluation systems in the prior art are solved.

The application discloses a raw coal pore detection method, device, system and medium based on nuclear magnetic resonance. The method comprises the following steps: obtaining relaxation time distribution data of each coal sample based on nuclear magnetic resonance T2 test; obtaining total integral areas of a plurality of nuclear magnetic resonance T2 spectra corresponding to each coal sample based on the relaxation time distribution data of each coal sample; performing statistical analysis on the relative standard deviation of the total integral areas of each coal sample to obtain the relative standard deviation corresponding to each coal sample; and determining the coal sample parameters of a target coal sample for detecting the pore structure of the raw coal according to the coal sample parameters of the coal sample corresponding to the relative standard deviation satisfying the preset condition. The raw coal pore detection method provided by the application can determine the target coal sample by selecting the coal sample parameters of the coal sample satisfying the preset condition, so that the result of the nuclear magnetic resonance T2 test for detecting the pore structure of the raw coal is more accurate and stable.

The invention relates to the field of detection, in particular to a food detection method based on low-field nuclear magnetic resonance, which can monitor the fluctuation of an applied pulse so as to determine the deviation of the overturning angle of a hydrogen atom nucleus in a sample caused by the fluctuation of the pulse and further determine the actual overturning angle. Furthermore, the interference of pulse fluctuation on an external magnetic field is also considered, and the influence of the pulse fluctuation on the relaxation duration is fully eliminated according to the actual relaxation duration determined by the actual overturning angle and the interference of the external magnetic field, so that the performance of the hydrogen nucleus in the sample can be accurately represented; further, the substance state of the sample can be accurately determined.

The invention belongs to the technical field of reservoir pore structure characterization, and relates to a nuclear magnetic resonance T2 spectrum pore diameter conversion method based on a least square method and mercury injection data. The method comprises the following steps: interpolating and fitting cumulative distribution frequency of nuclear magnetic resonance about relaxation time to obtain a relationship between the cumulative distribution frequency of the relaxation time and the radius of a mercury injection pore; interpolation and fitting are carried out on the cumulative distribution frequency of the high-pressure mercury injection relative to the pore radius, and the relation between the cumulative distribution frequency of the pore radius and the mercury injection pore radius is obtained; establishing an error function based on the relationship between the cumulative distribution frequency of the relaxation time and the mercury injection pore radius and the relationship between the cumulative distribution frequency of the pore radius and the mercury injection pore radius; establishing a conversion function for converting the cumulative distribution curve of the nuclear magnetic resonance T2 relaxation time into a cumulative distribution curve of a high-pressure mercury injection pore throat radius; and substituting the error function into a conversion function to solve a conversion coefficient in the conversion function, and completing nuclear magnetic resonance T2 spectrum aperture conversion.

This application discloses a downhole nuclear magnetic resonance (NMR) inversion method, apparatus, equipment, and storage medium based on pruned Bayesian methods, relating to the field of NMR data processing technology. The method includes: constructing a forward dataset based on fluid relaxation time and acquisition parameters, and adding Gaussian white noise to obtain the inversion input signal; initializing prior parameters, posterior mean, and variance; constructing a kernel matrix based on relaxation time points; constructing a kernel-dictionary matrix using Gaussian functions; updating the fitted echo data and fitting residuals using hierarchical Bayesian methods, thereby updating the prior parameters; updating the posterior mean through evidence maximization and calculating the proportion of each fluid component; pruning the kernel-dictionary matrix according to a preset pruning threshold and proportion, iterating until a termination condition is met, and finally mapping to obtain a two-dimensional NMR relaxation spectrum. This method solves the problem of waiting time and loss of diffusion relaxation dimension information caused by improved logging efficiency, which makes accurate multidimensional NMR logging inversion difficult.

A traceable multi-mode extremely weak magnetic field measuring device and method, comprising helium-3 atoms and an atomic magnetometer in a spin-exchange relaxation-free state, the helium-3 atoms polarized by metastable exchange optical pumping under an extremely weak magnetic field provide a traceable magnetic field value for the atomic magnetometer, the value is compared with the output response of the atomic magnetometer to obtain a calibrated scale factor of the atomic magnetometer, so that the measurement values of the atomic magnetometer are traceable. The atomic magnetometer meter head comprises four independent detection channels, the four detection channels are obtained by beam splitting of two detection lasers with different frequency detuning amounts, and the channels have high consistency. The method proposed by the application is compatible with the cooperative use of multiple probes, and can realize single-meter-head multi-channel measurement, meter-head internal magnetic field gradient measurement and meter-head inter-magnetic field gradient measurement three measurement modes, each mode has high consistency and high sensitivity.

Provided are a photon up-conversion film, a photon up-conversion body, a laminate, and an energy conversion device, which are capable of high-efficiency up-conversion, and methods of producing the same. The photon up-conversion film according to an embodiment of the present invention includes a color-forming portion containing at least: a sensitizing component capable of absorbing light in a first wavelength region λ1; and a light-emitting component capable of radiating light in a second wavelength region λ2 including wavelengths shorter than those of the first wavelength region λ1. A relaxation time of the photon up-conversion film measured by a spin-echo method through use of time-domain nuclear magnetic resonance (pulse NMR) at 298 K is less than 210 ms.

This invention discloses a method and system for testing rock pore size distribution curves based on nuclear magnetic resonance (NMR) technology. The method includes: preprocessing the rock sample to be tested and obtaining the porosity and transverse relaxation time curves of the sample at room temperature and low temperature; obtaining the measured value of unfrozen water content by the ratio of low-temperature to room-temperature porosity, serving as an objective benchmark for verifying theoretical results; converting the room-temperature relaxation curve into a cumulative pore size distribution curve, fitting and extracting pore characteristic parameters, and substituting relevant characteristic parameters into a theoretical model to calculate the theoretical value of unfrozen water content; iteratively optimizing the transverse surface relaxation rate to ensure the deviation between the theoretical and measured values ​​meets accuracy requirements; establishing a precise correspondence between relaxation time and pore radius; and outputting the final pore size distribution curve. Each step is interconnected and mutually supportive, forming a complete logical closed loop. This provides reliable technical support for characterizing rock pore structure.

A method for generating magnetic resonance (MR) images of a subject includes performing, using a magnetic resonance imaging (MRI) system, a steady-state pulse sequence to acquire MR data from a region of interest in the subject. The steady-state pulse sequence includes a contrast-modifying (CM) radio frequency (RF) pulse applied periodically at a predetermined time interval followed by a gradient spoiler pulse. The CM RF pulse has a flip angle with a value determined based on a minimum Ernst angle for a set of one or more background tissues in the region of interest that the CM RF pulse is configured to suppress with respect to a tissue of interest. The method further includes generating an image with Ti contrast based on the acquired MR data.

Disclosed is a method for characterising a sample (E), said method comprising magnetically coupling the sample to a microwave resonator (RHS) such that the coupling dominates the relaxation dynamics of an electron spin (SEL) of a paramagnetic centre of the sample, and determining, by nuclear-magnetic-resonance spectroscopy, coefficients Cij of coupling between a nuclear spin of the sample, called the probe nuclear spin (SNi), and other nuclear spins (SNj, SNk) of the sample, said method employing indirect detection of a state of said probe nuclear spin (SNi), through counting of microwave photons, of respective noise signals (SBS) produced by the return to equilibrium of said electron spin (SEL). An apparatus for implementing such a method is also disclosed.

The application discloses a method for predicting the limited mass transfer efficiency of a two-dimensional separation membrane by using dielectric spectrum, comprising the following steps: S1, respectively measuring the dielectric spectrum of water in the two-dimensional separation membrane and a reference membrane in the range of 10 ‑3 ~ 10 3 Hz, calculating the dielectric relaxation time after obtaining the dielectric relaxation frequency; S2, judging the limited mass transfer efficiency of water in the two-dimensional separation membrane according to the dielectric relaxation time ratio τ / τ0 of the dielectric relaxation time τ of water in the two-dimensional separation membrane and the dielectric relaxation time τ0 of the reference membrane; when the τ / τ0 is less than 1, it is judged that the limited mass transfer efficiency of water in the two-dimensional separation membrane is higher than that of the reference membrane; when the τ / τ0 is greater than 1, it is judged that the limited mass transfer efficiency of water in the two-dimensional separation membrane is lower than that of the reference membrane. The method can accurately predict the limited mass transfer efficiency of different types of two-dimensional separation membranes, effectively reflect the state and relative transmission rate of water in the interlayer of the two-dimensional separation membrane, and provide technical support for the research on the high-efficiency separation two-dimensional membrane.

Methods and systems herein may perform nuclear magnetic resonance measurements, and nuclear magnetic resonance tools, the method and systems comprising: acquiring, using an NMR sensor a first NMR signal from a volume in a subterranean region, wherein the first NMR signal is acquired using a first acquisition window. Further, acquiring, using the NMR sensor a second NMR signal from a volume in the subterranean region, wherein the second NMR signal is acquired using a second acquisition window different from the first acquisition window, wherein the first NMR signal and the second NMR signal form an NMR relaxation data; determining, using the first NMR signal and the second NMR signal, a correction term. Finally, the correction term may be used to acquire a corrected relaxation data set.

Method for obtaining a high-quality, purely chemical NMR shift spectrum, characterized in that it comprises the following steps: 1) Using the Matlab program to simulate a free induction attenuation signal and thus generate a purely chemical shift spectrum dataset for random NMR waves, and performing a Fourier transform of the FID signal to obtain a purely chemical NMR shift spectrum dataset and a corresponding labeling dataset; 2) Simulating the real-time ZS spectra as input data for a neural network by generating different chemical shift values, different signal-to-noise ratios, different spectrum peak intensities, different lateral relaxations, and different coupling strengths, and simultaneously simulating an ideal pure shift spectrum whose chemical shift, spectrum peak intensity, and lateral relaxation correspond to the simulated real-time ZS spectra, without coupling intensity information, without noise, and without data splice pseudopeaks as label data; creating a dataset with the input data and the label dataset, and dividing the dataset into a training set and a test set, which contains test data; 3) Perform preprocessing of data normalization for all datasets, including training set and test set; 4) Designing a structure of a neural network model of high-quality, purely chemical shift spectra that can achieve effects such as noise reduction, pseudopeak removal, linewidth reduction, and other effects; 5) Using the test data to test the neural network model, inputting the test data after preprocessing into the neural network model to obtain high-quality pure chemical shift spectra in order to output a high-quality pure chemical NMR shift spectrum that corresponds to the real-time ZS spectrum.

The application discloses a method for determining the lower limit of movable fluid in water drive gas reservoirs and a preparation method thereof, and belongs to the technical field of oilfield development. T 2The conversion relationship between the relaxation time and the pore throat radius is derived and established by considering the bound water film thickness, the bound water film thickness, the maximum pore throat radius and the minimum pore throat radius of the rock sample are calculated and obtained; the change characteristics of the nuclear magnetic resonance T 2The residual gas saturation of the rock sample after water drive gas is calculated and obtained by using the fractal theory, the theoretical expression of the lower limit of the movable fluid pore diameter, the lower limit of the movable fluid porosity and the lower limit of the movable fluid permeability considering the bound water film thickness is respectively derived and established; the lower limits of the movable fluid pore diameter, the porosity and the permeability in the water drive gas process are respectively calculated and evaluated by using the Newton iteration algorithm and the numerical integration algorithm in combination with the theoretical expression and the related parameters.

A contrast agent for magnetic resonance imaging (MRI) is proposed, comprising a polarizable agent (tracer) possessing a nuclear spin, wherein tracer molecules can be brought into a polarized state by polarizing their nuclear spins, and a retarder, wherein a molecular interaction of retarder molecules with the tracer molecules results in a prolongation of the T1 relaxation time of the tracer. Furthermore, a method for the production of a hyperpolarized contrast agent, a retarder for use in a contrast agent for MRI, a contrast agent for use in a diagnostic procedure in vivo and / or in vitro, and the use of a retarder in a contrast agent for MRI to prolong the T1 relaxation time of the tracer are proposed.

Provided are a photonic up-conversion film, a photonic up-conversion body, a laminate, and an energy conversion device capable of high-efficiency up-conversion, and a method for manufacturing the same. The photonic up-conversion film of an embodiment of the present application has a color development portion that contains at least a sensitizing component capable of absorbing light in a first wavelength range λ1 and a luminescent component capable of emitting light in a second wavelength range λ2 shorter in wavelength than the first wavelength range λ1. With respect to the photonic up-conversion film, the relaxation time measured by the spin echo method using the time-domain nuclear magnetic resonance method (pulse NMR) at 298 K is less than 210 ms.

The application is based on a SERF gyroscope multi-parameter measurement method of magnetic field phase frequency response, first measuring B y The phase frequency characteristic curve of the alternating magnetic field response is obtained through a lock-in amplifier y The response phase of the SERF atomic spin gyroscope under the alternating magnetic field is zero; different amplitude direct current magnetic fields are applied to the z axis respectively, the above process is repeated, and then B y The linear fitting of the zero-phase frequency value of the alternating magnetic field response can obtain the accurate values of the electronic magnetic field and the slowing-down factor. The method can realize the accurate measurement of the electronic magnetic field, the nuclear spin magnetic field, the slowing-down factor and the alkali metal atom density of the SERF atomic spin gyroscope in a very short time without causing the relaxation of the SERF atomic spin gyroscope.

The invention relates to the field of diagnostic reagents, in particular to a dual-marker dual-mode quantitative detection probe, a preparation method thereof and application of the dual-marker dual-mode quantitative detection probe in aortic dissection diagnosis. Compared with a traditional probe, the dual-marker dual-mode quantitative detection probe has the advantages that fluorescence-magnetic resonance relaxation dual-mode signals do not interfere with one another, and synchronous quantification can be achieved. The application advantage in aortic dissection diagnosis is that the detection rate of the aortic dissection can be remarkably improved by simultaneous detection of the double markers, and misdiagnosis generated during detection of a single marker is avoided. Meanwhile, double indexes can be obtained through single detection, repeated sampling is avoided, and the detection time is effectively shortened.

Provided in the present invention is a relaxation exchange magnetic resonance imaging (REXI) sequence, comprising: a filtering module, consisting of a 90° excitation radio frequency pulse and a 180° refocusing radio frequency pulse; an exchange module, consisting of a 90° excitation radio frequency pulse and an exchange delay; and a detection module, consisting of a 90° excitation radio frequency pulse and a plurality of 180° refocusing radio frequency pulses. Paired crusher gradient pulses are applied to the filtering module and the detection module, and a spoiler gradient pulse is applied to the exchange module. Further disclosed in the present invention is an acquisition and analysis method for the REXI sequence: during REXI acquisition, the echo time of the filtering module is fixed, and only the exchange delay time of the exchange module and the echo time of the detection module are changed; and during REXI analysis, a dual-chamber exchange model is used for fitting data. Further disclosed in the present invention is the use of the REXI sequence and the acquisition and analysis method thereof in measuring transmembrane transport of cerebrospinal fluid by magnetic resonance imaging, which is especially suitable for magnetic resonance imaging for rapidly measuring the speed of molecular exchange between a short T2 component and a long T2 component in a dual-component system.

The invention relates to the technical field of tobacco leaf detection, in particular to a tobacco leaf oil content quantitative characterization method. The method comprises the following steps: measuring state information of protons in a tobacco leaf sample by using low-field nuclear magnetic resonance to obtain a spin-spin relaxation time T2 spectrum and a spin-lattice relaxation time T1 spectrum, and generating a T1-T2 two-dimensional spectrogram; determining peak positions of low-activity protons and medium-activity protons in the T1-T2 two-dimensional spectrogram to obtain T2 values of the low-activity protons and the medium-activity protons, and solving an average T2 value of the low-activity protons and the medium-activity protons of the plurality of groups of tobacco leaf samples; on the spin-spin relaxation time T2 spectrum of the tobacco leaf sample to be detected, the low-activity proton peak intensity and the medium-activity proton peak intensity of the tobacco leaf sample to be detected at the average T2 value are obtained, and the ratio of the low-activity proton peak intensity to the medium-activity proton peak intensity serves as the oil content quantitative value of the tobacco leaf sample to be detected. According to the method, nondestructive testing of the tobacco leaf raw material oil content is realized by utilizing a low-field nuclear magnetic technology, and quantitative characterization of the tobacco leaf raw material oil content is realized by combining the T1-T2 two-dimensional spectrogram.

The invention discloses a nuclear magnetic resonance signal noise suppression method and device based on a convolutional neural network. The method comprises the following steps: configuring a CPMG pulse sequence in nuclear magnetic resonance equipment; carrying out nuclear magnetic resonance testing on the shale sample based on the CPMG pulse sequence, setting a plurality of groups of echo intervals by utilizing a multi-time micro-variation echo interval technology, and generating a time-aligned multi-dimensional data set; segmenting a multi-dimensional data set by using a sliding window technology, performing segmented data processing through a pre-trained CNN network, removing noise components and performing signal reconstruction; a reinforcement learning mechanism is introduced, and according to the quality of de-noised echo signals, pulse sequence configuration parameters and a sliding window segmentation strategy are reversely optimized, so that the continuous and stable noise suppression effect is ensured. According to the method, the signal acquisition and processing process is optimized, the interference of noise on the fast relaxation component signal is reduced by using the convolutional neural network, the recognition accuracy of the signal is improved, and technical support is provided for accurate representation of the reservoir.