High field and near zero field combined magnetic resonance system and detection method

Abstract

The invention provides a high-field and near-zero-field combined magnetic resonance system, which comprises a sample tube for placing a sample, a high-field measurement module for pre-polarization of the sample and high-field chemical shift spectrum measurement, and a near-zero-field magnetic resonance module for J coupling signal measurement of the sample in the near-zero field, the sample transmission module is used for driving a sample to move between a high field and a near-zero field and maintaining nuclear spin polarization of the sample in the moving process; the digital control and signal processing module is used for automatic control and synchronous signal acquisition of the high field measurement module and the near-zero field magnetic resonance module; the invention also provides a high field and near zero field combined magnetic resonance detection method and a measurement method. According to the invention, a high-field spectrogram and a near-zero-field spectrogram are obtained in one measurement cycle, and unified correspondence of chemical shift and J coupling is realized. Through combination of high-field pre-polarization and rapid shuttling, the signal-to-noise ratio of near-zero field measurement is improved by about one order of magnitude, and the spectral line width is significantly reduced.

Description

Technical Field

[0001] This invention belongs to the field of nuclear magnetic resonance (NMR) measurement technology, specifically relating to a magnetic resonance system combining high field and near-zero field, and a magnetic resonance detection method combining high field and near-zero field. It is applicable to applications such as near-zero field magnetic resonance measurement, shuttle magnetic resonance technology, non-destructive testing, biomedical imaging, relaxation spectrum measurement, biological metabolism detection, and magnetic resonance analysis of metal-containing samples. Background Technology

[0002] Traditional nuclear magnetic resonance (NMR) measurements are mostly performed under high-field (HF) conditions. Higher magnetic field strength generally leads to higher signal intensity and measurement sensitivity. With increasing static magnetic field strength, the sensitivity and spectral resolution of NMR have significantly improved, making high-field NMR a core direction for technological development in this field (J. Keeler, Understanding NMR Spectroscopy. (Wiley, 2010)). However, the cost of high-field systems increases dramatically with magnet strength; they are bulky, complex to install, and require extremely high-level shimming techniques. Furthermore, HF NMR still has several inherent limitations: 1. High-resolution spectroscopy is usually only applicable to homogeneous samples; 2. It is difficult to be compatible with metals or conductive containers; 3. It relies on shimming and locking systems, increasing operational complexity and maintenance costs. As the magnetic field strength increases, the absolute field homogeneity of the magnet decreases, often leading to spectral broadening and signal drift, making it unsuitable for long-term or large-scale measurements.

[0003] Near-zero field nuclear magnetic resonance (NMR) is an emerging magnetic resonance mode that performs measurements in the zero-field and ultra-low-field (ZULF) regions. This method obtains nuclear spin information without relying on high magnetic fields to generate chemical shift differences, thus avoiding several problems faced by traditional NMR in complex systems. Typical problems include: spectral line broadening caused by differences in magnetic susceptibility in complex materials, limited radio frequency penetration depth of conductive samples, and the adverse effects of metal containers on detection sensitivity. Progress in Nuclear Magnetic Resonance Spectroscopy 148-149, 101558(2025)). However, since the signal-to-noise ratio of magnetic resonance is approximately B0 of the magnetic field strength. 3 / 2 Due to the extremely low intrinsic signal strength under low magnetic fields, ZULF NMR typically requires external pre-polarization or hyperpolarization. Furthermore, the interaction between nuclear spin and the magnetic field is weak under extremely low magnetic fields, making it difficult to obtain chemical shift information. In addition, ZULF NMR signal frequencies are usually in the Hz range, where traditional induction coils have extremely low sensitivity, making effective detection difficult.

[0004] With the development of optically pumped magnetometer (OPM) technology, researchers can directly detect magnetic resonance signals in extremely low magnetic field environments, leading to the rapid advancement of ZULF NMR (Nature Physics 3, 227-234 (2007)). However, despite the significant improvement in low-field detection sensitivity by OPM, the overall ZULF NMR signal is still about two orders of magnitude lower than that of high-field NMR, limiting its application in naturally abundant or low-concentration biological samples. Currently, ZULF NMR is mostly limited to isotope-labeled systems, which constitutes a significant bottleneck in its application in biomedical detection.

[0005] In recent years, to overcome the limitations of high-field and near-zero-field magnetic resonance, researchers have proposed various shuttle or variable-field magnetic resonance techniques. For example, a type of rapid shuttle device based on a high-field NMR system can achieve rapid round-trip of the sample between the polarization region and the detection region in a high magnetic field region (Phys. Chem. Chem. Phys. 20, 12396–12405(2018)). Such systems typically use a high-field magnet as the sole detection field, mainly for enhancing polarization transfer or performing time-resolved measurements, but do not perform J-coupled spectroscopy measurements under near-zero-field conditions. Another type of shuttle system based on ZULF NMR (PNAS Nexus 4, (2025)) uses a higher magnetic field for sample pre-polarization, thereby significantly improving the signal-to-noise ratio, but its signal acquisition process is entirely carried out in a near-zero-field environment, making it impossible to obtain high-field characteristic information such as chemical shift. In addition, there is a class of variable-field NMR devices based on hyperpolarization technology (Analytical Chemistry 97, 17336–17344 (2025)), which achieves hyperpolarization through chemical or physical processes to replace magnets for sample prepolarization, enabling the simultaneous detection of ZULF and low-field spectral signals. However, this method is limited by the type and lifetime of the hyperpolarized substrate, and the magnetic field strength required for polarization transfer is relatively low, resulting in less pronounced high-field features such as chemical shift in the obtained signal.

[0006] Existing technologies indicate that although high-field shuttle systems and ZULF shuttle systems have made progress in their respective fields, they remain functionally independent: the former focuses on the resolution and polarization capability of high-field chemical shift spectra, while the latter emphasizes the sensitivity and structural resolution capability of near-zero-field J-coupled spectra. To date, no device can simultaneously perform high-field and near-zero-field measurements on the same platform, achieving direct correspondence and joint acquisition of chemical shift and J-coupled spectra. Therefore, there is an urgent need for a comprehensive device capable of rapid shuttle between high and near-zero fields, performing both magnetic resonance measurements within the same system. This would combine high-field sensitivity with low-field high resolution, thereby expanding the application range of magnetic resonance technology in complex samples and naturally abundant systems. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing high-field and near-zero-field NMR systems, which are independent and cannot achieve corresponding spectral signal measurements. This invention proposes a combined high-field and near-zero-field NMR system and detection method. By enabling rapid sample transport between the high-field and near-zero-field within the same device, the high-field chemical shift spectrum and the near-zero-field J-coupled spectrum can be acquired separately in a single measurement sequence, thereby achieving the correspondence and joint analysis of the two types of spectral information on a single platform.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A combined high-field and near-zero-field magnetic resonance system includes a sample tube for placing a sample, a high-field measurement module for pre-polarization and high-field chemical shift spectrum measurement of the sample, a near-zero-field magnetic resonance module for measuring the J-coupled signal of the sample in the near-zero field, a sample transport module for driving the sample to move between the high field and the near-zero field and maintaining the nuclear spin polarization of the sample during the movement, and a digital control and signal processing module for automated control and synchronous acquisition of signals from the high-field measurement module and the near-zero-field magnetic resonance module.

[0009] The high-field measurement module includes a high-field detection coil and a high-field magnet. A high-field sample area is set on the central axis of the high-field magnet. The high-field detection coil is arranged around the high-field sample area and is connected to the high-field spectrometer.

[0010] The near-zero field magnetic resonance module includes a radio frequency excitation coil, an atomic magnetometer array, a magnetic shielding device, and an FPC triaxial shimming coil. The geometric center region inside the magnetic shielding device is the near-zero field sample region. The FPC triaxial shimming coil is installed on the inner wall of the magnetic shielding device. The radio frequency excitation coil is located in the near-zero field sample region. The atomic magnetometer array is installed inside the magnetic shielding device. The radio frequency excitation coil, the atomic magnetometer array, and the FPC triaxial shimming coil are all connected to the digital control and signal processing module.

[0011] The magnetic shielding device comprises multiple layers of magnetic shielding covers, the magnetic shielding covers being made of a high-permeability alloy, and the thickness of the magnetic shielding covers being... The spacing between adjacent magnetic shields is .

[0012] The radio frequency excitation coil includes a pair of Helmholtz coils and two pairs of saddle coils. The central axes of the three pairs of coils are orthogonal to each other and fixed on the coil frame, which is located in the near-zero field sample region.

[0013] The atomic magnetometer array contains multiple atomic magnetometers, which are arranged symmetrically and linearly along the central axis of the magnetic shielding device. The atomic magnetometers are miniaturized Rb atomic optically pumped magnetometers.

[0014] The sample transfer module includes a sample chamber, a solenoid, a slide rail, an active synchronous pulley, a driven synchronous pulley, a drive motor, and a synchronous belt. The first end of the solenoid passes through the near-zero field sample region along the central axis of the magnetic shielding device, and the second end of the solenoid is located on the central axis of the high-field magnet and within the high-field magnet. An atomic magnetometer array is installed on the outer wall of the solenoid, and a coil frame is fitted around the outer periphery of the solenoid. The slide rail passes through the tube hole of the solenoid, and the second end of the slide rail passes through the high-field sample region. A driven synchronous pulley is installed in the extension direction of the second end of the slide rail, and a drive motor is installed in the extension direction of the first end of the slide rail. An active synchronous pulley is installed on the drive shaft of the drive motor. The active synchronous pulley and the driven synchronous pulley are connected by a synchronous belt, which is an annular belt with racks on both the inner and outer ring surfaces. The synchronous belt has an inner ring surface as its transmission surface. The synchronous belt meshes with both the driving and driven synchronous pulleys via a rack on the transmission surface. The outer ring surface of the synchronous belt is its transmission surface. The synchronous belt is divided into a series of interconnected sections: a driving synchronous pulley engagement section, a first transmission section, a driven synchronous pulley engagement section, and a second transmission section. Both the first and second transmission sections are vertical straight sections. The rack on the transmission surface of either the first or second transmission section meshes with a rack on the sample chamber. A sample tube is fixedly mounted on the sample chamber. Driven by the synchronous belt, the sample chamber reciprocates along a slide rail, causing the sample in the sample tube to reciprocate between the high-field sample region and the near-zero-field sample region. The solenoid and drive motor are connected to the digital control and signal processing modules, respectively.

[0015] The sample chamber includes a sample holder, slide rails and slide bars, and a transmission rack. The sample tube is fixed on the sample holder. Slide rails and slide bars are provided at both ends of the sample holder. The slide rails and slide bars are adapted to the slide rails. A transmission rack is provided on the side of the sample holder. The transmission rack meshes with the rack of the transmission surface of the synchronous belt.

[0016] A magnetic resonance detection method combining high-field and near-zero-field, utilizing the aforementioned magnetic resonance system combining high-field and near-zero-field, includes the following steps: Step 1: Adjust the current input to the FPC triaxial shimming coil through the digital control and signal processing module to make the FPC triaxial shimming coil generate a compensation field opposite to the direction of the residual magnetic field in the environment, thereby establishing a near-zero field measurement environment. Step 2: Adjust the current of the solenoid through the digital control and signal processing module to form a stable guiding field along the sample transport direction; Step 3: Start the atomic magnetometer array and perform zero-point compensation and sensitivity calibration on each channel of the atomic magnetometer; Step 4: Control the drive motor to rotate through the digital control and signal processing module, move the sample in the sample tube to the high field sample area, and use the high field magnet to thermally polarize the sample. Step 5: After the sample is polarized, the high-field spectrometer controls the high-field detection coil to apply a conventional single-pulse or multi-pulse sequence to acquire the high-field nuclear magnetic resonance signal of the sample and obtain the high-field chemical shift spectrum of the sample. Step 6: After the high-field NMR signal acquisition is completed, wait for the set time to allow the sample to return to polarization equilibrium. Then, control the drive motor to rotate through the digital control and signal processing module, so that the sample leaves the high-field sample region and moves quickly along the slide rail to the near-zero field sample region. Step 7: After the sample reaches the near-zero field sample region, a pulse current is applied to the radio frequency excitation coil through the digital control and signal processing module. The intensity and duration of the pulse current are adjusted to achieve nuclear spin excitation of the sample. Step 8: Start the atomic magnetometer array, measure the magnetic resonance signal of the sample under near-zero field, and output the corresponding near-zero field J-coupled spectrum; Step 9: Perform corresponding analysis on the high-field chemical shift spectrum obtained in Step 5 and the near-zero field J-coupling spectrum obtained in Step 8 to achieve joint analysis of chemical shift information and spin coupling information, thereby obtaining the complete magnetic resonance characteristic spectrum of the sample.

[0017] A magnetic resonance measurement method combining high-field and near-zero-field, utilizing the aforementioned magnetic resonance system combining high-field and near-zero-field, includes the following steps: Step 1: Adjust the current input to the FPC triaxial shimming coil through the digital control and signal processing module to make the FPC triaxial shimming coil generate a compensation field opposite to the direction of the residual magnetic field in the environment, thereby establishing a near-zero field measurement environment. Step 2: Adjust the current of the solenoid through the digital control and signal processing module to form a stable guiding field along the sample transport direction; Step 3: Start the atomic magnetometer array and perform zero-point compensation and sensitivity calibration on each channel of the atomic magnetometer; Step 4: Control the drive motor to rotate through the digital control and signal processing module, move the sample in the sample tube to the high field sample area, and use the high field magnet to thermally polarize the sample. Step 5: After the sample is polarized, the high-field spectrometer controls the high-field detection coil to apply radio frequency pulses, converting the longitudinal magnetization of the sample into transverse coherence; the sample then evolves freely in the static magnetic field of the high-field magnet to perform the first step of phase correlation analysis on the chemical shift. The second indirect dimension encoding, the first Secondary indirect dimension coding evolution time , Indirect dimension encoding sequence number, The preset step time is used; the high-field detection coil applies a radio frequency pulse to convert the encoded transverse coherence into longitudinal magnetization, thereby realizing the storage of phase information and completing one indirect 3D encoding. Step 6: After completing the indirect dimension encoding, the drive motor is rotated by the digital control and signal processing module, so that the sample leaves the high field sample area and moves quickly along the slide rail to the near zero field sample area. Step 7: After the sample reaches the near-zero field sample region, a pulsed current is applied to the radio frequency excitation coil through the digital control and signal processing module. This converts the longitudinal magnetization of the phase information stored in the sample into a near-zero field observable coherent signal, and generates a direct-dimensional time-dependent spin evolution process dominated by near-zero field J-coupling. Related magnetic field signals, atomic magnetometer array pairs and direct dimension time The relevant magnetic field signals were acquired in the time domain to obtain the first... Secondary indirect dimension coding evolution time Corresponding direct-dimensional time-domain signal ; Step 8: Repeat steps 4 to 7 to obtain a set of random numbers. Secondary indirect dimension coding evolution time Changes in direct-dimensional time-domain signals ,in, , The numbers are natural numbers, thus forming a two-dimensional dataset, which is then processed along the direct dimension of time. Performing a Fourier transform yields the near-zero field J-coupled spectrum dimension. Then, along the indirect dimension encoding evolution time Performing a Fourier transform yields the high-field chemical shift correlation spectrum dimension. Finally, a two-dimensional correlation spectrum was obtained. .

[0018] Compared with the prior art, the present invention has the following advantages: 1. This invention utilizes a high-field magnet as a pre-polarization source and combines it with a rapid shuttle mechanism to transfer the sample from the high-field magnet to the near-zero field region in a very short time, thereby achieving polarization preservation and high signal-to-noise ratio detection. This significantly improves the sensitivity and spectral resolution of ZULF NMR and expands its application range in the detection of naturally abundant samples. 2. By arranging a multi-channel miniaturized Rb atomic magnetometer array, the system can achieve parallel detection of multi-nucleus signals, improving spatial resolution and overall detection sensitivity; 3. The solenoid design effectively maintains the stability of the sample's spin polarization direction during sample movement; 4. This invention can achieve joint spectral acquisition of high-field and near-zero-field in a single measurement sequence, completing two-dimensional or multi-dimensional correlation measurements of chemical shift spectra and J-coupled spectra. Since the Larmor frequencies of different nuclear spins tend to be consistent under near-zero field conditions, this invention can simultaneously detect multinuclear signals, providing a new means for multinuclear correlation spectroscopy and structural analysis. Attached Figure Description

[0019] Figure 1 A schematic diagram of a magnetic resonance system combining high and near-zero fields; Figure 2 This is a schematic diagram of the sample chamber structure; Figure 3 for J-coupling spectrum under near-zero field; This figure shows a typical J-coupled spectrum signal of the sample measured by an atomic magnetometer array under near-zero magnetic field conditions. The spectrum exhibits a single-peak structure, corresponding to... spin pairs The spectral peaks indicate that the present invention can obtain a high-resolution J spectrum; Figure 4 for High-field chemical shift spectra under a 9.4T magnet; (a) is the carbon spectrum, (b) is the proton spectrum; this figure shows the chemical shift spectra of the same sample measured in a high-field NMR system, with the peaks corresponding to the carbonyl group of formic acid. and Its splitting distance and Figure 3 The peak frequencies of the J spectrum in the spectrum are completely consistent, proving that the present invention can realize the integrated joint measurement of high-field chemical shift spectrum and near-zero field J coupling spectrum; Among them: 1-High field detection coil, 2-Sample tube, 3-Driven synchronous belt pulley, 4-Sample chamber, 5-Slide rail, 6-High field magnet, 7-Solenoid, 8-RF excitation coil, 9-Atomic magnetometer array, 10-Magnetic shielding device, 11-FPC triaxial shimming coil, 12-Drive motor, 13-Digital control and signal processing module, 14-Slide rail and slider, 15-Transmission rack, 16-Sample holder, 17-Synchronous belt, 18-High field sample area. Detailed Implementation

[0020] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0021] Example 1: This invention provides a magnetic resonance system that combines high-field and near-zero-field magnetic fields, enabling rapid shuttle of the sample between high magnetic fields and near-zero magnetic fields, thereby obtaining the high-field chemical shift spectrum and the near-zero-field J-coupled spectrum of the sample, and realizing the joint analysis of the two types of spectral information.

[0022] like Figure 1As shown, a magnetic resonance system combining high-field and near-zero-field measurements includes a sample tube 2, a high-field measurement module, a digital control and signal processing module 13, a near-zero-field magnetic resonance module, and a sample transfer module. The high-field measurement module is used for sample pre-polarization and high-field chemical shift spectrum measurement. The digital control and signal processing module 13 is used to realize the automated control of the entire system and the synchronous acquisition of signals from the high-field measurement module and the near-zero-field magnetic resonance module. The near-zero-field magnetic resonance module is used for measuring the J-coupled signal of the sample (placed in the sample tube 2) in the near-zero field. The sample transfer module is used to drive the sample to move back and forth between the high field and the near-zero field and to maintain the nuclear spin polarization of the sample during the movement, thereby realizing sequential measurement of the two field (high field and near-zero field) regions.

[0023] The high-field measurement module includes a high-field detection coil 1 and a high-field magnet 6. A high-field sample region 18 is positioned on the central axis of the high-field magnet 6, and the high-field detection coil 1 is arranged around the high-field sample region 18. The high-field sample region 18 is located in the geometric center region inside the high-field magnet 6. The high-field detection coil 1 is connected to a high-field spectrometer. When the sample tube 2 is transferred to the center of the high-field magnet 6, the high-field spectrometer controls the high-field detection coil 1 to emit a standard pulse sequence and acquire high-field chemical shift spectra. The high field of the high-field magnet 6 serves as the pre-polarization field of the sample, providing high nuclear spin polarization for subsequent near-zero field measurements of the sample. The high-field measurement module and the high-field spectrometer, as a high-field nuclear magnetic resonance spectrometer system, can employ a commercially available high-field nuclear magnetic resonance spectrometer system (e.g., 9.4 T Bruker NMR).

[0024] Furthermore, the high-field detection coil 1 is a hydrogen nucleus. With carbon nucleus The detection coil.

[0025] The near-zero field magnetic resonance module includes a radio frequency excitation coil 8, an atomic magnetometer array 9, a magnetic shielding device 10, and an FPC triaxial shim coil 11. The FPC triaxial shim coil 11 is disposed on the inner wall of the magnetic shielding device 10. The FPC triaxial shim coil 11 is used to actively compensate for the residual environmental magnetic field inside the magnetic shielding device 10, thereby achieving a near-zero magnetic field environment inside the magnetic shielding device 10. The geometric center region inside the magnetic shielding device 10 is the near-zero field sample region. The radio frequency excitation coil 8 surrounds the near-zero field sample region and is used to generate radio frequency excitation pulses in the near-zero field sample region to excite and manipulate the sample nuclei spin. The atomic magnetometer array 9 is disposed inside the magnetic shielding device 10 and is used for non-contact detection of the sample magnetic resonance signal.

[0026] Furthermore, the magnetic shielding device 10 includes multiple layers of magnetic shielding cover, the material of which is a high magnetic permeability alloy, and the thickness of the magnetic shielding cover is [missing information]. The spacing between adjacent magnetic shields is In this embodiment, the magnetic shielding cover is made of permalloy, and the magnetic shielding device 10 has a shielding factor better than [missing information]. The FPC triaxial shimming coil 11 is set on the inner wall of the innermost magnetic shield.

[0027] Furthermore, the radio frequency excitation coil 8 includes a pair of Helmholtz coils and two pairs of saddle coils. The central axes of the three pairs of coils are orthogonal to each other (each pair of coils is treated as a whole) and fixed on the coil frame, which is located in the near-zero field sample region. The radio frequency excitation coil 8 can generate radio frequency pulse magnetic fields in any direction in a near-zero field environment, enabling selective excitation and flipping of the nuclear spins of different samples.

[0028] Furthermore, the atomic magnetometer array 9 comprises multiple atomic magnetometers, which are miniaturized Rb atom optically pumped magnetometers. Each atomic magnetometer achieves high-sensitivity magnetic field measurement through optical pumping and probe light. The operating bandwidth of the atomic magnetometer is within [missing information]. Within the range, the magnetic field sensitivity of the atomic magnetometer is better than... The atomic magnetometers are installed inside the magnetic shielding device 10 and arranged symmetrically and linearly along the central axis of the magnetic shielding device 10. The array layout of the atomic magnetometers can significantly improve the detection sensitivity and spatial resolution of the magnetic resonance signal and enable multi-channel parallel acquisition.

[0029] The sample transfer module includes a sample chamber 4, a solenoid 7, a slide rail 5, an active synchronous pulley, a driven synchronous pulley 3, a drive motor 12, and a synchronous belt 17.

[0030] The first end of the solenoid 7 passes through the near-zero field sample region of the magnetic shielding device 10 along the central axis of the magnetic shielding device 10, and the tail end of the solenoid 7 is located on the central axis of the high field magnet 6 and is located in the high field magnet 6. The high field sample region 18 is located at the extension of the tail end of the solenoid 7. The tube hole of the solenoid 7 is the channel for the sample to shuttle between the high field and the near-zero field. The solenoid 7 generates a uniform guiding field in the direction of its central axis (i.e., the direction of sample movement) to maintain the nuclear spin polarization of the sample during the shuttle process between the high field and the near-zero field. An atomic magnetometer array 9 is provided on the outer wall of the solenoid 7, and a coil frame is sleeved on the outer periphery of the solenoid 7.

[0031] Furthermore, the coil of the solenoid 7 is wound in a double-layer, unidirectional spiral, with the two layers of coils wound in the same direction and connected in series. This ensures that the current direction of the two layers of coils is consistent, resulting in superimposed magnetic fields. This structure can form a highly uniform guiding field inside the solenoid 7, with a large internal-external field strength ratio. This allows the atomic magnetometer array 9 to operate stably under a higher background field and maintain the consistency of polarization direction of the sample during its shuttle process between high and near-zero fields.

[0032] The slide rail 5 passes through the bore of the solenoid 7, and its tail end passes through the high-field sample region 18 at the center of the high-field magnet 6. A driven synchronous pulley 3 is provided in the extending direction of the tail end of the slide rail 5 (the driven synchronous pulley 3 is fixed on a non-metallic bearing, which is fixed in the extending direction of the tail end of the slide rail 5). A drive motor 12 is provided in the extending direction of the head end of the slide rail 5. A drive synchronous pulley is provided on the drive shaft of the drive motor 12. The drive synchronous pulley and the driven synchronous pulley 3 are connected by a synchronous belt 17. The synchronous belt 17 is an annular belt with racks on both the inner and outer ring surfaces. The inner ring surface of the synchronous belt 17 is the transmission surface. The synchronous belt 17 meshes with the driving synchronous pulley and the driven synchronous pulley 3 respectively through the rack on the transmission surface. The outer ring surface of the synchronous belt 17 is the transmission surface, and the rack is provided on the transmission surface. The synchronous belt 17 is divided into a driving synchronous pulley engagement section, a first transmission section, a driven synchronous pulley engagement section, and a second transmission section, which are connected end to end in a ring. The first transmission section and the second transmission section are both vertical straight sections. The racks on the transmission surfaces of the first transmission section and the second transmission section can both mesh with the racks provided on the sample chamber 4. In this embodiment, the rack of the first transmission section meshes with the rack provided on the sample chamber 4. The drive motor 12, the active synchronous pulley, the driven synchronous pulley 3, and the synchronous belt 17 constitute a synchronous belt transmission system. When the drive shaft of the drive motor 12 rotates, the active synchronous pulley rotates synchronously with the drive shaft of the drive motor 12. The active synchronous pulley drives the synchronous belt 17 to move, and the synchronous belt 17 drives the sample chamber 4 to move up and down reciprocally. A sample tube 2 is fixedly installed on the sample chamber 4. The slide rail 14 of the sample chamber 4 is adapted to be connected to the slide rail 5. The sample chamber 4 moves reciprocally along the slide rail 5 under the drive of the synchronous belt 17, so that the sample in the sample tube 2 moves back and forth between the high field sample region 18 and the near zero field sample region.

[0033] Furthermore, the slide rail 5 is provided with blocking blocks at its front and rear ends, which can prevent the sample chamber 4 from falling off the slide rail 5.

[0034] In this embodiment, sample tube 2 is a standard nuclear magnetic resonance tube (outer diameter...). This is used to hold liquid or solution samples. The drive motor 12 is a non-magnetic servo motor, which reduces the typical transfer time for the sample to move from the high-field sample region 18 to the near-zero-field sample region to less than [time missing]. It can achieve repeatability accuracy better than .

[0035] Furthermore, such as Figure 2As shown, the sample chamber 4 includes a sample holder 16, a slide rail 14, and a transmission rack 15. The sample tube 2 is fixed on the sample holder 16, which is made of non-magnetic engineering plastic. The sample holder 16 has a sample tube through hole in the center for inserting the sample tube. The sample holder 16 can also fix the sample tube by engaging with the clip at the upper end of the sample tube. Slide rails 14 are provided at both ends of the sample holder 16. The slide rails 14 are adapted to and connected to the slide rail 5. The slide rails 14 can reciprocate relative to the slide rail 5. The transmission rack 15 is provided on the side of the sample holder 16. The transmission rack 15 meshes with the rack of the transmission surface of the synchronous belt 17. When the transmission surface of the synchronous belt 17 moves back and forth, the transmission rack 15 on the side of the sample holder 16 meshes with the rack of the transmission surface of the synchronous belt 17, driving the sample holder 16 to reciprocate along the slide rail 5, thereby realizing the rapid reciprocating movement of the sample in the sample tube 2 between the high-field sample region 18 and the near-zero-field sample region.

[0036] The digital control and signal processing module 13 is connected to the two layers of coils of the solenoid 7 for adjusting the guiding field; the digital control and signal processing module 13 is connected to the FPC triaxial shimming coil 11 for compensating for the residual magnetic field inside the magnetic shielding device 10; the digital control and signal processing module 13 is electrically connected to the radio frequency excitation coil 8 for outputting excitation pulses; the digital control and signal processing module 13 is connected to the atomic magnetometer array 9 for acquiring, amplifying, and digitizing low-field magnetic resonance signals, as well as synchronizing and automatically triggering the data after signal digitization. The digital control and signal processing module 13 is connected to the high-field spectrometer to share the timing trigger signals between the near-zero field and the high field, ensuring time synchronization between high-field and near-zero field measurements; the digital control and signal processing module 13 is connected to the drive motor 12 for controlling the forward and reverse rotation of the drive motor 12 to achieve the lifting and positioning of the sample along the slide rail 5.

[0037] In this invention, the sample shuttles back and forth along the same axis between the high field and the low field; both the high field measurement module and the near-zero field magnetic resonance module can provide a stable magnetic field environment; the atomic magnetometer array 9 and the high field spectrometer are synchronized in time under the same control platform, thereby completing the joint magnetic resonance measurement of the high field and the near-zero field.

[0038] Example 2: The present invention also provides a magnetic resonance detection method combining high field and near-zero field, utilizing the magnetic resonance system combining high field and near-zero field as described in embodiment 1, comprising the following steps: Step 1, Magnetic Field Compensation: The current input to the FPC triaxial shimming coil 11 is adjusted by the digital control and signal processing module 13, so that the FPC triaxial shimming coil 11 generates a compensation field opposite to the direction of the residual magnetic field in the environment, thereby weakening the net magnetic field in the central region inside the magnetic shielding device 10 to near zero, and realizing the establishment of a near-zero field measurement environment.

[0039] Step 2, Guide Field Adjustment: The current of the solenoid 7 is adjusted by the digital control and signal processing module 13 to form a stable guide field along the sample transport direction. This guide field remains constant during the rapid reciprocating motion of the sample between the high-field sample region 18 and the near-zero-field sample region, and is used to maintain the nuclear spin polarization direction from flipping.

[0040] Step 3, Atomic Magnetometer Calibration: Start the atomic magnetometer array 9 and perform zero-point compensation and sensitivity calibration on each channel of the atomic magnetometer to ensure accurate acquisition of the subsequent near-zero field signal.

[0041] Step 4, Sample Polarization: The digital control and signal processing module 13 controls the drive motor 12 to rotate, moving the sample in the sample tube 2 (the sample tube 2 is fixed on the sample holder 16) to the high field sample area 18. The high field magnet 6 is used to thermally polarize the sample, providing high nuclear polarization for subsequent measurements (including high field measurements and near-zero field measurements).

[0042] Step 5, High-field measurement: After the sample is polarized, the high-field spectrometer controls the high-field detection coil 1 to apply a single pulse or multi-pulse sequence to acquire the high-field nuclear magnetic resonance signal of the sample and obtain the high-field chemical shift spectrum of the sample.

[0043] Step Six: Sample Transfer: After the high-field NMR signal acquisition is completed, wait for a period of time to allow the sample to return to polarization equilibrium (usually the longitudinal relaxation time of the sample). More than twice the size of the sample in the sample tube 2), and then the digital control and signal processing module 13 controls the drive motor 12 to rotate, thereby moving the sample in the sample tube 2 away from the high field sample area 18 and quickly moving it along the slide rail 5 to the near zero field sample area.

[0044] Step 7, Low-field excitation: After the sample reaches the near-zero field sample region, a pulse current is applied to the radio frequency excitation coil 8 through the digital control and signal processing module 13. The intensity and duration of the pulse current are adjusted to achieve nuclear spin excitation of the sample.

[0045] Step 8, Signal Acquisition: Start the atomic magnetometer array 9, measure the magnetic resonance signal of the sample under near-zero field, and output the corresponding near-zero field J coupling spectrum.

[0046] Step 9, Data Analysis: The high-field chemical shift spectrum obtained in Step 5 is compared with the near-zero field J-coupling spectrum obtained in Step 8 to achieve joint analysis of chemical shift information and spin coupling information, thereby obtaining the complete magnetic resonance characteristic spectrum of the sample.

[0047] This system can acquire both high-field and near-zero-field spectra in a single measurement cycle, achieving a unified correspondence between chemical shift and J-coupling. Through a combination of high-field pre-polarization and rapid shuttle, the signal-to-noise ratio of near-zero-field measurements is improved by approximately one order of magnitude, and the spectral linewidth is significantly reduced. The system is compact and precisely controlled, and can be widely applied in fields such as natural abundance sample detection, biological metabolic analysis, and relaxation spectroscopy measurements.

[0048] Example 3: To verify the feasibility and detection performance of the device of the present invention, naturally abundant formic acid (HCOOH) was selected as a sample, and the high-field chemical shift spectrum and the near-zero field J-coupled spectrum were measured in the combined high-field and near-zero-field magnetic resonance system described in Example 1.

[0049] 1. Experimental conditions Sample mounted on outer diameter In a standard MRI tube, the total volume The experimental steps are as follows: First, in the high-field measurement module ( Thermal polarization is performed in the magnet, and data is acquired using a conventional single-pulse sequence. Chemical shift spectroscopy; subsequently, the digital control and signal processing module 13 controls the drive motor 12 to rotate, and the sample is in... Internal transfer to the interior of near-magnetic shielding device 10 (residual field) After a radio frequency pulse is applied in the near-zero field (inside the magnetic shielding device 10), the signal is detected and acquired by the atomic magnetometer array 9.

[0050] 2. Detection Results like Figure 3 As shown, this is the near-zero field J-coupled spectrum of formic acid obtained in this invention, with the horizontal axis representing frequency and the unit being... The vertical axis represents the signal amplitude. The spectrum exhibits a typical J-spectral peak, which is... Spectral linewidth is less than The signal-to-noise ratio is significantly higher than that of the traditional ZULF system. This result demonstrates that the present invention can achieve efficient detection of high-resolution J-coupled signals in naturally abundant samples. Figure 4 (a) and Figure 4 (b) shows the high-field chemical shift spectrum of the same sample (formic acid) obtained in this invention, measured in a 9.4 T magnet. Figure 4 (a) is the carbon spectrum. Figure 4 (b) is the proton spectrum, with the horizontal axis representing chemical shifts, in units of... The vertical axis represents the normalized signal intensity, where it can be seen that... Resonance and The resonant signal. The peak splitting spacing of this signal corresponds perfectly to the near-zero field J-peak frequency, indicating that a one-to-one mapping can be achieved between high-field and low-field signals (near-zero field in this embodiment) in this invention.

[0051] 3. Results Analysis The experimental results above demonstrate that this invention can achieve sequential acquisition of both high-field and near-zero-field spectra in a single experimental cycle, and the obtained J-coupling constant perfectly matches that obtained from the high-field chemical shift spectrum, proving that the system can achieve a unified correlation between the two magnetic resonance dimensions. Furthermore, due to the combination of high-field prepolarization and rapid shuttle, the signal-to-noise ratio of ZULF measurements is improved by approximately one order of magnitude, and the spectral linewidth is significantly reduced.

[0052] This embodiment fully verifies the feasibility and effectiveness of the system of the present invention in achieving joint magnetic resonance measurement under multiple field strength conditions, indicating that the system has good stability and broad scientific research and application prospects.

[0053] Example 4: To achieve two-dimensional correlation measurement of high-field chemical shift information and near-zero field J coupling information of the same sample, this invention also provides a magnetic resonance measurement method combining high-field and near-zero fields, utilizing the magnetic resonance system combining high-field and near-zero fields described in Embodiment 1, including the following steps: Step 1, Magnetic Field Compensation: The current input to the FPC triaxial shimming coil 11 is adjusted by the digital control and signal processing module 13, so that the FPC triaxial shimming coil 11 generates a compensation field opposite to the direction of the residual magnetic field in the environment, thereby weakening the net magnetic field in the central region inside the magnetic shielding device 10 to near zero, and realizing the establishment of a near-zero field measurement environment.

[0054] Step 2, Guide Field Adjustment: The current of the solenoid 7 is adjusted by the digital control and signal processing module 13 to form a stable guide field along the sample transport direction. This guide field remains constant during the rapid reciprocating motion of the sample between the high-field sample region 18 and the near-zero-field sample region, and is used to maintain the nuclear spin polarization direction from flipping.

[0055] Step 3, Atomic Magnetometer Calibration: Start the atomic magnetometer array 9 and perform zero-point compensation and sensitivity calibration on each channel of the atomic magnetometer to ensure accurate acquisition of the subsequent near-zero field signal.

[0056] Step 4, Sample Polarization: The digital control and signal processing module 13 controls the drive motor 12 to rotate, moving the sample in the sample tube 2 to the high-field sample region 18. The high-field magnet 6 is used to thermally polarize the sample, providing high nuclear polarization for subsequent measurements (including high-field measurements and near-zero-field measurements). At this time, the magnetization direction of the sample is longitudinal magnetization.

[0057] Step 5: High-field indirect dimension coding ( After the sample is polarized, a "high-field coding sequence" for two-dimensional spectral indirection is executed within the high-field measurement module. Specifically, the high-field spectrometer controls the high-field detection coil 1 to apply radio frequency pulses, converting the longitudinal magnetization of the sample into transverse coherence; subsequently, the sample freely evolves in the static magnetic field of the high-field magnet 6 to perform the first step of chemical shift-related phase analysis. The second indirect dimension encoding (indirect dimension encoding is implemented through free evolution), the third Secondary indirect dimension coding evolution time , Indirect dimension encoding sequence number, The preset step time is used. Then, an radio frequency pulse is applied to the high-field detection coil 1 to convert the encoded transverse coherence into longitudinal magnetization, thereby storing the phase information and completing one indirect 3D encoding.

[0058] Step 6, Sample Transfer: After completing the indirect dimension encoding, the drive motor 12 is rotated by the digital control and signal processing module 13, thereby moving the sample in the sample tube 2 away from the high field sample region 18 and quickly moving it along the slide rail 5 to the near zero field sample region, thus maintaining the stability of the nuclear spin polarization direction and the stored longitudinal magnetization state during the shuttle process.

[0059] Step 7: Near-zero field direct readout ( After the sample reaches the near-zero field sample region, a pulse is applied to the radio frequency excitation coil 8 via the digital control and signal processing module 13. This converts the longitudinal magnetization of the phase information stored in the sample into a near-zero field observable coherent signal, and generates a direct-dimensional time-dependent spin evolution process dominated by near-zero field J coupling. The associated magnetic field signal was then analyzed by a nine-pair atomic magnetometer array and compared with the direct dimension time. The relevant magnetic field signals were acquired in the time domain to obtain the first... Secondary indirect dimension coding evolution time Corresponding direct-dimensional time-domain signal .

[0060] Step 8, Repeated Acquisition and Two-Dimensional Fourier Transform: Repeat steps 4 to 7 to obtain a set of data. Secondary indirect dimension coding evolution time Changes in direct-dimensional time-domain signals ,in, , For natural numbers, the first... The direct-dimensional time-domain signal is obtained through indirect 3D encoding. As the second two-dimensional dataset This allows us to obtain a two-dimensional dataset by dividing the dataset into columns along the direct dimension of time. (The near-zero field J-coupled spectrum dimension is obtained by performing a Fourier transform on the column direction of the two-dimensional dataset) ; and then along the indirect dimension encoding evolution time (The high-field chemical shift correlation spectrum dimension is obtained by performing a Fourier transform on the horizontal direction of the two-dimensional dataset.) Finally, a two-dimensional correlation spectrum was obtained. This enables a two-dimensional correlation characterization of the chemical shift information and J-coupling information of the same sample. It should be noted that the direct dimension time corresponds to the direct dimension sampling time axis of each ZULF readout. During the two-dimensional Fourier transform, this is achieved along the direct dimension time... The object of the Fourier transform is the evolution time of each indirect dimension code. Direct time-domain signals acquired Indirect dimensional encoding evolution time Corresponding to the artificially increased "indirect evolution time" in high-field coding, it is not directly sampled as an electrical signal, but rather, through a chain of "encoding-storage-transfer-readout," it ultimately manifests as the evolution time of the two-dimensional dataset with the indirect dimension coding. The changes, during the two-dimensional Fourier transform, occur along the indirect dimension encoding evolution time. The object is a two-dimensional dataset. Discrete sequences on the indirect dimension.

[0061] Effect Description: Compared to obtaining single-dimensional spectra under only a single magnetic field condition, this embodiment unifies high-field chemical shift resolution and near-zero field J-coupling high-resolution characteristics into a two-dimensional spectrum within the same platform; wherein, the digital control and signal processing module 13 is used to realize the evolution time The incremental scanning, sample shuttle triggering, radio frequency excitation, and atomic magnetometer array acquisition timing synchronization are all achieved. The solenoid guiding field is used to improve polarization maintenance and repeatability during the shuttle process, thereby enhancing the stability and spectral line resolution of two-dimensional spectral measurements.

[0062] It should be noted that the specific embodiments described in this invention are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains can make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A magnetic resonance system combining high-field and near-zero-field, comprising a sample tube (2) for placing a sample, characterized in that, It also includes a high-field measurement module for pre-polarization and high-field chemical shift spectrum measurement of the sample, a near-zero field magnetic resonance module for J-coupled signal measurement of the sample in the near-zero field, a sample transport module for driving the sample to move between the high field and the near-zero field and maintaining the nuclear spin polarization of the sample during the movement, and a digital control and signal processing module (13) for automated control and for synchronous acquisition of signals between the high-field measurement module and the near-zero field magnetic resonance module.

2. The magnetic resonance system combining high field and near-zero field according to claim 1, characterized in that, The high field measurement module includes a high field detection coil (1) and a high field magnet (6). A high field sample area (18) is set on the central axis of the high field magnet (6). The high field detection coil (1) is set around the high field sample area (18) and located in the geometric center region inside the high field magnet (6). The high field detection coil (1) is connected to the high field spectrometer.

3. A magnetic resonance system combining high field and near-zero field according to claim 2, characterized in that, The near-zero field magnetic resonance module includes a radio frequency excitation coil (8), an atomic magnetometer array (9), a magnetic shielding device (10), and an FPC triaxial shimming coil (11). The geometric center region inside the magnetic shielding device (10) is the near-zero field sample region. The inner wall of the magnetic shielding device (10) is provided with an FPC triaxial shimming coil (11). The radio frequency excitation coil (8) is located in the near-zero field sample region. The magnetic shielding device (10) is provided with an atomic magnetometer array (9). The radio frequency excitation coil (8), the atomic magnetometer array (9), and the FPC triaxial shimming coil (11) are all connected to the digital control and signal processing module (13).

4. A magnetic resonance system combining high field and near-zero field according to claim 2, characterized in that, The magnetic shielding device (10) comprises a multi-layer magnetic shielding cover, the material of which is a high-permeability alloy, and the thickness of which is [missing information]. The spacing between adjacent magnetic shields is .

5. A magnetic resonance system combining high field and near-zero field according to claim 2, characterized in that, The radio frequency excitation coil (8) includes a pair of Helmholtz coils and two pairs of saddle coils. The central axes of the three pairs of coils are orthogonal to each other and fixed on the coil frame. The coil frame is located in the near-zero field sample region.

6. A magnetic resonance system combining high field and near-zero field according to claim 2, characterized in that, The atomic magnetometer array (9) contains multiple atomic magnetometers, which are arranged symmetrically and linearly along the central axis of the magnetic shielding device (10). The atomic magnetometers are miniaturized Rb atomic optical pump magnetometers.

7. A magnetic resonance system combining high field and near-zero field according to claim 3, characterized in that, The sample transfer module includes a sample chamber (4), a solenoid (7), a slide rail (5), an active synchronous pulley, a driven synchronous pulley (3), a drive motor (12), and a synchronous belt (17). The first end of the solenoid (7) runs through the near-zero field sample area along the central axis of the magnetic shielding device (10), and the tail end of the solenoid (7) is located on the central axis of the high-field magnet (6) and is located in the high-field magnet (6). An atomic magnetometer array (9) is provided on the outer wall of the solenoid (7). A coil frame is fitted around the outer periphery of the tube (7). The slide rail (5) passes through the tube hole of the solenoid (7) and the tail end of the slide rail (5) passes through the high field sample area (18). A driven synchronous pulley (3) is provided in the extension direction of the tail end of the slide rail (5). A drive motor (12) is provided in the extension direction of the head end of the slide rail (5). An active synchronous pulley is provided on the drive shaft of the drive motor (12). The active synchronous pulley and the driven synchronous pulley (3) are connected by a synchronous belt (17). The synchronous belt (17) is an annular belt with racks on both its inner and outer ring surfaces. The inner ring surface of the synchronous belt (17) is the transmission surface. The synchronous belt (17) meshes with the active synchronous pulley and the driven synchronous pulley (3) respectively through the racks on the transmission surface. The outer ring surface of the synchronous belt (17) is the transmission surface. The synchronous belt (17) is divided into an active synchronous pulley engagement section, a first transmission section, a driven synchronous pulley engagement section, and a second transmission section, which are connected end to end in an annular shape. The first transmission section and the second transmission section are both vertical straight sections. The racks on the transmission surface of the first transmission section or the second transmission section mesh with the racks on the sample chamber (4). The sample chamber (4) is fixedly provided with a sample tube (2). The sample chamber (4) moves back and forth along the slide rail (5) under the drive of the synchronous belt (17), so that the sample in the sample tube (2) moves back and forth between the high field sample area (18) and the near zero field sample area. The solenoid (7) and the drive motor (12) are connected to the digital control and signal processing module (13) respectively.

8. A magnetic resonance system combining high field and near-zero field according to claim 7, characterized in that, The sample chamber (4) includes a sample holder (16), a slide rail (14), and a transmission rack (15). The sample tube (2) is fixed on the sample holder (16). Slide rails (14) are provided at both ends of the sample holder (16). The slide rails (14) are adapted to the slide rail (5). The side of the sample holder (16) is provided with a transmission rack (15). The transmission rack (15) meshes with the rack of the transmission surface of the synchronous belt (17).

9. A magnetic resonance detection method combining high field and near-zero field, utilizing the magnetic resonance system combining high field and near-zero field as described in claim 7, comprising the following steps: Step 1: Adjust the current input to the FPC triaxial shimming coil (11) through the digital control and signal processing module (13) so that the FPC triaxial shimming coil (11) generates a compensation field opposite to the direction of the residual magnetic field in the environment, thereby establishing a near-zero field measurement environment; Step 2: Adjust the current of the solenoid (7) through the digital control and signal processing module (13) to form a stable guiding field along the sample transport direction; Step 3: Start the atomic magnetometer array (9) and perform zero-point compensation and sensitivity calibration on each channel atomic magnetometer; Step 4: Control the drive motor (12) to rotate through the digital control and signal processing module (13) to move the sample in the sample tube (2) to the high field sample area (18) and use the high field magnet (6) to thermally polarize the sample; Step 5: After the sample is polarized, the high-field spectrometer controls the high-field detection coil (1) to apply a conventional single pulse or multi-pulse sequence to acquire the high-field nuclear magnetic resonance signal of the sample and obtain the high-field chemical shift spectrum of the sample. Step 6: After the high-field nuclear magnetic resonance signal acquisition is completed, wait for a set time to allow the sample to return to polarization equilibrium. Then, control the drive motor (12) to rotate through the digital control and signal processing module (13) so that the sample leaves the high-field sample area (18) and moves quickly along the slide rail (5) to the near-zero field sample area. Step 7: After the sample reaches the near-zero field sample region, a pulse current is applied to the radio frequency excitation coil (8) through the digital control and signal processing module (13). The intensity and duration of the pulse current are adjusted to achieve nuclear spin excitation of the sample. Step 8: Start the atomic magnetometer array (9), measure the magnetic resonance signal of the sample under near-zero field, and output the corresponding near-zero field J coupling spectrum; Step 9: Perform corresponding analysis on the high-field chemical shift spectrum obtained in Step 5 and the near-zero field J-coupling spectrum obtained in Step 8 to achieve joint analysis of chemical shift information and spin coupling information, thereby obtaining the complete magnetic resonance characteristic spectrum of the sample.

10. A method for magnetic resonance measurement combining high field and near-zero field, utilizing the magnetic resonance system combining high field and near-zero field as described in claim 7, comprising the following steps: Step 1: Adjust the current input to the FPC triaxial shimming coil (11) through the digital control and signal processing module (13) so that the FPC triaxial shimming coil (11) generates a compensation field opposite to the direction of the residual magnetic field in the environment, thereby establishing a near-zero field measurement environment; Step 2: Adjust the current of the solenoid (7) through the digital control and signal processing module (13) to form a stable guiding field along the sample transport direction; Step 3: Start the atomic magnetometer array (9) and perform zero-point compensation and sensitivity calibration on each channel atomic magnetometer; Step 4: Control the drive motor (12) to rotate through the digital control and signal processing module (13) to move the sample in the sample tube (2) to the high field sample area (18) and use the high field magnet (6) to thermally polarize the sample; Step 5: After the sample is polarized, the high-field spectrometer controls the high-field detection coil (1) to apply a radio frequency pulse, converting the longitudinal magnetization of the sample into transverse coherence; the sample evolves freely in the static magnetic field of the high-field magnet (6) to perform the first phase correlation analysis on the chemical shift. The second indirect dimension encoding, the first Secondary indirect dimension coding evolution time , Indirect dimension encoding sequence number, The preset step time is used; the high field detection coil (1) applies a radio frequency pulse to convert the encoded transverse coherence into longitudinal magnetization, realizes the storage of phase information, and thus completes one indirect 3D encoding; Step 6: After completing the indirect dimension encoding, the drive motor (12) is controlled to rotate by the digital control and signal processing module (13), so that the sample leaves the high field sample area (18) and moves quickly along the slide rail (5) to the near zero field sample area. Step 7: After the sample reaches the near-zero field sample region, a pulsed current is applied to the radio frequency excitation coil (8) through the digital control and signal processing module (13). This converts the longitudinal magnetization of the phase information stored in the sample into a near-zero field observable coherent signal, and generates a direct-dimensional time-dependent spin evolution process dominated by near-zero field J-coupling. The relevant magnetic field signal, atomic magnetometer array (9) versus direct dimension time The relevant magnetic field signals were acquired in the time domain to obtain the first... Secondary indirect dimension coding evolution time Corresponding direct-dimensional time-domain signal ; Step 8: Repeat steps 4 to 7 to obtain a set of random numbers. Secondary indirect dimension coding evolution time Changes in direct-dimensional time-domain signals ,in, , The numbers are natural numbers, thus forming a two-dimensional dataset, which is then processed along the direct dimension of time. Performing a Fourier transform yields the near-zero field J-coupled spectrum dimension. Then, along the indirect dimension encoding evolution time Performing a Fourier transform yields the high-field chemical shift correlation spectrum dimension. Finally, a two-dimensional correlation spectrum was obtained. .

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