A multi-channel parallel broadband microwave modulation polarization enhancement device and enhancement method

Abstract

This invention discloses a multi-channel parallel broadband microwave modulation polarization enhancement device and method. The device includes a nuclear magnetic resonance (NMR) spectrometer, comprising a microwave source, an NMR probe, an RF power amplifier, and a control console. The microwave source includes a signal generation module, one or more parallel microwave output channels, and a combiner. The signal generation module is electrically connected to one or more microwave output channels. The outputs of one or more microwave channels are combined by the combiner and fed into the NMR probe. The RF power amplifier is electrically connected to the probe. The control console controls the microwave source and the RF power amplifier. The method is based on multi-channel parallel microwave pulses with wide spectral characteristics. Frequency modulation is used to optimize the combined microwave pulses to match free radical samples with a certain electron paramagnetic resonance linewidth, achieving efficient dynamic nuclear polarization. This invention can significantly improve the signal-to-noise ratio of the NMR signal while broadening the excitation bandwidth and improving polarization efficiency, effectively shortening the experimental time.

Description

Technical Field

[0001] This invention relates to the field of nuclear magnetic resonance technology, specifically to a multi-channel parallel broadband microwave modulation polarization enhancement device and method. Background Technology

[0002] Dynamic nuclear polarization (DNP) technology can significantly enhance nuclear magnetic resonance (NMR) signal intensity, greatly improve the NMR signal-to-noise ratio, and accelerate magnetic resonance imaging (MRI) efficiency. Traditional DNP technology often uses single-frequency microwave irradiation to obtain electron polarization. However, due to the inhomogeneity of the main magnetic field and the anisotropy of the free radical's g-factor, these factors cause non-uniform broadening of the electron excitation band, resulting in the dispersion of free electrons over a wide excitation frequency range. Therefore, for free radical samples with a certain electron paramagnetic resonance (EPR) linewidth, single-frequency microwaves suffer from low excitation efficiency and power redundancy.

[0003] In contrast, the DNP method, which can fully utilize the entire electronic spectrum, has significant advantages. Because it allows all electrons to directly participate in the hyperpolarization process, this type of method usually requires microwave scanning of a wide electronic linewidth. However, due to the limitation of adiabatic conditions, the scanning speed is slow, and the efficiency is often low. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a multi-channel parallel broadband microwave modulation polarization enhancement device and method. By using a multi-channel parallel approach to achieve broadband excitation within the EPR linewidth, it can improve excitation efficiency, shorten scan time, and further enhance the signal-to-noise ratio of nuclear magnetic resonance signals.

[0005] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0006] According to a first aspect of this application, a multi-channel parallel broadband microwave modulation polarization enhancement device is provided, comprising:

[0007] Nuclear magnetic resonance spectrometer, including microwave source, nuclear magnetic resonance probe, radio frequency power amplifier and control console;

[0008] The microwave source includes a signal generation module, one or more parallel microwave output channels, and a combiner. The signal generation module is electrically connected to the one or more parallel microwave output channels, and each of the one or more parallel microwave output channels is electrically connected to the combiner. The one or more parallel microwave output channels are used to output one or more microwave pulses respectively, and the combiner is used to combine the one or more microwave pulses to generate a combined microwave pulse.

[0009] The nuclear magnetic resonance probe is electrically connected to the combiner;

[0010] The radio frequency power amplifier is electrically connected to the nuclear magnetic resonance probe;

[0011] The control console is connected to the microwave source and the radio frequency power discharge respectively;

[0012] Through a dynamic nuclear polarization process, the nuclear magnetic resonance probe is used to irradiate a free radical sample with a combination of microwave pulses, thereby exciting the unpaired electrons in the free radical sample to resonate and transition. Through the coupling between electrons and nuclei, the high electron spin polarization is transferred to the target nucleus. The radio frequency power amplifier is used to amplify the radio frequency pulse power to excite the target nucleus. The control console acquires the nuclear magnetic resonance signal.

[0013] In some embodiments of this application, based on the foregoing scheme, the following further methods are also included:

[0014] The console controls the microwave source module via a first TTL signal, the console controls the radio frequency power amplifier via a second TTL signal, and the console acquires the nuclear magnetic resonance signal.

[0015] In some embodiments of this application, based on the foregoing scheme, the following further methods are also included:

[0016] A first isolator is disposed between the combiner and the nuclear magnetic resonance probe;

[0017] A second isolator is disposed between the radio frequency power amplifier and the nuclear magnetic resonance probe.

[0018] In some embodiments of this application, based on the aforementioned scheme, an EPR spectrometer is used to detect the EPR line shape of the free radical sample used to obtain the EPR line width;

[0019] The number of parallel microwave output channels to be used is determined based on the EPR linewidth.

[0020] Based on the number of microwave output channels and the EPR linewidth used, the microwave pulse parameters output by each microwave output channel are set respectively;

[0021] A specific frequency microwave pulse is generated by a signal generation module, and then the microwave pulses are output separately through each microwave output channel. All microwave pulses are combined by a combiner to generate a combined microwave pulse.

[0022] The combined microwave pulses are fed into the nuclear magnetic resonance probe. Through the dynamic nuclear polarization process, the nuclear magnetic resonance probe irradiates the free radical sample with the combined microwave pulses, exciting the unpaired electrons of the free radical sample to resonantly transition. Through the coupling between electrons and nuclei, the high electron spin polarization of the free radical sample is transferred to the target nucleus.

[0023] The target nucleus is excited by amplifying the power of the radio frequency pulse through a radio frequency power amplifier, and the nuclear magnetic resonance signal is acquired by the control console.

[0024] In some embodiments of this application, based on the foregoing scheme, the microwave pulse parameters include the interval between adjacent microwave output channels, microwave pulse spectral width, microwave pulse spectral amplitude, microwave pulse power, and microwave pulse delay time, wherein,

[0025] The formula for calculating the interval between adjacent microwave output channels is:

[0026]

[0027] in, The interval between adjacent microwave output channels For EPR line width, This refers to the number of microwave output channels. The spectral linewidth is mediated by hyperfine interactions;

[0028] The microwave pulse spectral width satisfies:

[0029] ,

[0030] in, For the first The microwave pulse spectrum width of each microwave output channel;

[0031] The formula for calculating the amplitude of the microwave pulse spectrum is as follows:

[0032]

[0033] in, This is the center frequency of the microwave spectrum currently output by this microwave output channel. The amplitude of the microwave pulse spectrum. The center frequency of the microwave spectrum EPR spectral amplitude at the location;

[0034] The formula for calculating the microwave pulse power is as follows:

[0035]

[0036] in, For the first Microwave pulse power of each microwave output channel This represents the channel power at the maximum value of the EPR spectral line. For the first EPR spectrum integral of the range covered by each microwave output channel The integral of the EPR spectrum is the range covered by the microwave output channel corresponding to the maximum value of the EPR spectral line.

[0037] In some embodiments of this application, based on the foregoing scheme, the microwave pulse parameters further include a scan rate, the calculation formula for which is:

[0038] ,

[0039] in, For the first The scan rate of each microwave output channel This refers to the scan time.

[0040] The scanning rate satisfies:

[0041]

[0042] in, For electron spin-lattice relaxation time, For scan rate;

[0043] At the same time, insulation conditions must be met:

[0044]

[0045] in, It is the electronic Rabi frequency.

[0046] In some embodiments of this application, based on the foregoing scheme, the following further methods are also included:

[0047] Obtain enhancement factor The calculation formula is:

[0048]

[0049] in, The intensity of the nuclear magnetic resonance signal after being irradiated by a combination of microwave pulses. The intensity of the nuclear magnetic resonance signal is in thermal equilibrium.

[0050] According to a third aspect of this application, a computer-readable storage medium is provided that stores a computer program thereon, the computer program including executable instructions that, when executed by a processor, implement the method described above.

[0051] According to a fourth aspect of this application, an electronic device is provided, comprising:

[0052] One or more processors;

[0053] A memory for storing executable instructions of the processor, which, when executed by the one or more processors, cause the one or more processors to implement the method described above.

[0054] The beneficial effects of this application are as follows:

[0055] This application provides a multi-channel parallel broadband microwave modulation polarization enhancement device and method. A signal generation module generates microwave pulses of a specific frequency. One or more parallel microwave output channels are used to output one or more microwave pulses respectively. A combiner combines one or more microwave pulses to generate a combined microwave pulse, forming a multi-channel combined microwave pulse with broadband characteristics. During dynamic nuclear polarization, a nuclear magnetic resonance probe is used to irradiate a free radical sample with the combined microwave pulse, exciting the unpaired electrons of the free radical sample to resonantly transition. Through the coupling between electrons and nuclei, the high electron spin polarization of the free radical sample is transferred to the target nucleus. An RF power amplifier amplifies the RF pulse power to excite the target nucleus. The nuclear magnetic resonance signal is acquired through a control console. This addresses the problems of low electron excitation rate due to single-frequency excitation and slow scanning rate due to frequency sweep excitation in existing technologies, resulting in low excitation efficiency and power redundancy. Based on the multi-channel parallel microwave pulse with broadband characteristics, the combined microwave pulse is optimized through frequency modulation to match a free radical sample with a certain electron paramagnetic resonance linewidth, achieving efficient dynamic nuclear polarization. This invention can significantly improve the signal-to-noise ratio of nuclear magnetic resonance signals while broadening the excitation bandwidth and improving polarization efficiency, and effectively shorten the experimental scanning time.

[0056] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0057] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are intended to explain the invention, but do not constitute an undue limitation thereof. In the drawings:

[0058] Figure 1 This is a schematic diagram of the structure of the multi-channel parallel broadband microwave modulation polarization enhancement device of the present invention;

[0059] Figure 2 This is a schematic diagram of the multi-channel parallel broadband microwave modulation polarization enhancement method of the present invention;

[0060] Figure 3The system operating timing diagram of the multi-channel parallel broadband microwave modulation polarization enhancement device of the present invention;

[0061] Figure 4 This is a schematic diagram of the spectrum of the microwave frequency modulation combined pulse of the present invention. Detailed Implementation

[0062] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0063] It should be understood that the terms "comprising" and other similar expressions in the specification, claims, and accompanying drawings of this invention are intended to cover a non-exclusive inclusion, such as a process, method, system, or apparatus that includes a series of steps or units and is not limited to the listed steps or units. Furthermore, "first" and "second" are used to distinguish different objects and are not intended to describe a specific order.

[0064] Please see Figure 1 This paper presents a schematic diagram of a multi-channel parallel broadband microwave modulation polarization enhancement device. The multi-channel parallel broadband microwave modulation polarization enhancement device provided in this embodiment includes a nuclear magnetic resonance spectrometer, which includes a microwave source, a nuclear magnetic resonance probe, an RF power amplifier, and a control console.

[0065] The microwave source includes a signal generation module, one or more parallel microwave output channels, and a combiner. The signal generation module is electrically connected to one or more parallel microwave output channels, and each of the one or more parallel microwave output channels is electrically connected to the combiner. The one or more parallel microwave output channels are used to output one or more microwave pulses respectively, and the combiner is used to combine one or more microwave pulses to generate a combined microwave pulse.

[0066] The nuclear magnetic resonance probe is electrically connected to the combiner, the radio frequency power amplifier is electrically connected to the nuclear magnetic resonance probe, and the control console is connected to the microwave source and the radio frequency power amplifier respectively.

[0067] Through a dynamic nuclear polarization process, the nuclear magnetic resonance probe is used to irradiate a free radical sample with combined microwave pulses, exciting the unpaired electrons of the free radicals to resonantly transition. The high electron spin polarization of the free radical sample is transferred to the target nucleus through coupling between electrons and the nucleus. The radio frequency power amplifier amplifies the radio frequency pulse power to excite the target nucleus, and the nuclear magnetic resonance signal is acquired by the control console.

[0068] This embodiment provides a multi-channel parallel broadband microwave modulation polarization enhancement device. A signal generation module generates microwave pulses of a specific frequency. One or more parallel microwave output channels are used to output one or more microwave pulses respectively. A combiner combines one or more microwave pulses to generate a combined microwave pulse, forming a multi-channel combined microwave pulse with broadband characteristics. During dynamic nuclear polarization, a nuclear magnetic resonance probe irradiates a free radical sample with the combined microwave pulse, exciting the unpaired electrons of the free radical sample to resonantly transition. Through the coupling between electrons and nuclei, the high electron spin polarization of the free radical sample is transferred to the target nucleus. An RF power amplifier amplifies the RF pulse power to excite the target nucleus. The NMR signal is acquired by a control console. This solution addresses the problems of low electron excitation rate due to single-frequency excitation and slow scanning rate due to frequency sweep excitation in existing technologies, resulting in low excitation efficiency and power redundancy. Based on the multi-channel parallel microwave pulse with broadband characteristics, the combined microwave pulse is optimized through frequency modulation to match a free radical sample with a certain electron paramagnetic resonance linewidth, achieving efficient dynamic nuclear polarization. This invention can significantly improve the signal-to-noise ratio of nuclear magnetic resonance signals while broadening the excitation bandwidth and improving polarization efficiency, and effectively shorten the experimental scanning time.

[0069] In some embodiments of this example, the console can realize hardware control, data acquisition and signal processing functions by using TTL signals (Transistor-Transistor Logic Signal) and the conduction (low impedance state) and cutoff (high impedance state) characteristics of transistors.

[0070] Specifically, the control console controls the microwave source module via a first TTL signal. The output of one or more microwave pulses is controlled by the timing of the control console. The adjustable parameters of each channel's microwave pulse include, but are not limited to: the interval between adjacent microwave output channels, microwave pulse spectral width, microwave pulse spectral amplitude, microwave pulse power, and microwave pulse delay time. The control console controls the RF power amplifier via a second TTL signal. In addition, the control console can also be used to acquire nuclear magnetic resonance signals.

[0071] In some embodiments of this example, a first isolator is also included, which is disposed between the combiner and the MRI probe.

[0072] In some embodiments of this example, a second isolator is also included. The second isolator is disposed between the radio frequency power amplifier and the nuclear magnetic resonance probe to prevent signal reflection from damaging the instrument due to poor matching of the nuclear magnetic resonance probe.

[0073] In some embodiments of this example, an EPR spectrometer (electron paramagnetic resonance spectrometer) is also included. The EPR spectrometer is used to detect the EPR line shape of the free radical electron sample used to obtain the EPR linewidth. Based on the EPR linewidth, adjustable parameters of the microwave pulse for each channel are obtained. The adjustable parameters of the microwave pulse for each channel include the interval between adjacent microwave output channels, the microwave pulse spectral width, the microwave pulse spectral amplitude, the microwave pulse power, and the microwave pulse delay time.

[0074] According to the second aspect of this application, such as Figure 2 and Figure 3 As shown, this embodiment provides a multi-channel parallel broadband microwave modulation polarization enhancement method, including:

[0075] Step S1: Use an EPR spectrometer (Electron Paramagnetic Resonance Spectrometer) to detect the EPR line shape of the free radical electron sample used and obtain the EPR line width;

[0076] Step S2: Determine the number of parallel microwave output channels to be used based on the EPR linewidth;

[0077] Step S3: Based on the number of microwave output channels and EPR linewidth used, set the microwave pulse parameters output by each microwave output channel respectively;

[0078] Step S4: Generate microwave pulses of a specific frequency through the signal generation module, then output microwave pulses through each microwave output channel, and combine all microwave pulses through a combiner to generate a combined microwave pulse;

[0079] Step S5: Feed the combined microwave pulse into the nuclear magnetic resonance probe. Through the dynamic nuclear polarization process, the unpaired electron resonant transition of the free radical sample is excited. Through the coupling between electrons and nuclei, the high electron spin polarization of the free radical sample is transferred to the target nucleus.

[0080] Step S6: The radio frequency pulse power is amplified by the radio frequency power amplifier to excite the target nucleus, and then the nuclear magnetic resonance signal is acquired by the control console.

[0081] In some embodiments of this example, the EPR line shape refers to the shape characteristics of the signal peaks in the electron paramagnetic resonance (EPR) spectrum, which are manifested in the symmetry, width, splitting mode, etc. of the peaks. The EPR line width (usually referring to full width at half maximum, FWHM) is then obtained based on the EPR line shape.

[0082] In some embodiments of this example, the number of parallel microwave output channels used is selected according to the actual situation; this example does not limit this. After selecting the number of microwave output channels, the microwave pulse parameters output by each microwave output channel are set based on the number of microwave output channels used and the EPR linewidth.

[0083] In some embodiments of this example, the microwave pulse parameters include the interval between adjacent microwave output channels, the microwave pulse spectral width, the microwave pulse spectral amplitude, the microwave pulse power, and the microwave pulse delay time. By continuously optimizing the above parameters, a higher signal-to-noise ratio nuclear magnetic resonance signal can be obtained.

[0084] In some embodiments of this example, the spacing between adjacent microwave output channels is defined as the difference between the center frequencies of the microwave outputs from two adjacent channels. DNP enhancement increases linearly with the number of microwave spectra. However, system complexity and the actual number of channels need to be considered, while also being affected by the EPR linewidth. Spectral linewidth mediated by hyperfine interactions Due to limitations, the spacing between adjacent microwave output channels must meet the following requirements:

[0085] (1)

[0086] in, The interval between adjacent microwave output channels For EPR line width, This refers to the number of microwave output channels. The spectral width is mediated by hyperfine interactions.

[0087] In some embodiments of this example, the microwave pulse spectral width is defined as the spectral width of the microwave output from the microwave output channel. No frequency mixing should occur between the outputs of different microwave output channels, and the settings of the microwave output channels should meet the following requirements:

[0088] , (2)

[0089] in, For the first The microwave pulse spectrum width of each microwave output channel.

[0090] In some embodiments of this example, the microwave pulse spectrum amplitude is defined as the center frequency of the channel output microwave spectrum. Signal amplitude at that location. Microwave pulse spectral amplitude. Set to the center frequency of the microwave spectrum output by this microwave output channel. The formula for calculating the EPR signal amplitude at a given location and the microwave pulse spectrum amplitude is as follows:

[0091] (3)

[0092] in, The center frequency of the microwave spectrum The amplitude of the EPR spectrum signal at the location.

[0093] In some embodiments of this example, the microwave pulse power is defined as the microwave power value output by each channel. The channel power at the maximum value of the EPR spectral line is used as an example. For accuracy, the EPR spectrum integral of the range covered by its corresponding microwave output channel is denoted as... The output power of each channel is integrally calculated based on the EPR spectrum covering the range of each channel. and The microwave pulse power is allocated proportionally, and the formula for calculating the microwave pulse power is:

[0094] (4)

[0095] in, For the first Microwave pulse power of each microwave output channel This represents the channel power at the maximum value of the EPR spectral line. For the first EPR spectrum integral of the range covered by each microwave output channel The integral of the EPR spectrum is the range covered by the microwave output channel corresponding to the maximum value of the EPR spectral line.

[0096] In some embodiments of this example, the microwave pulse delay time of the microwave pulses output by each microwave output channel can be controlled via a control console. and ,according to Figure 3 First, set an initial one. Then, subtract the microwave pulse width from the single pulse repetition time. Subtract You can get . The following constraints must be met: .

[0097] like Figure 3 As shown, the microwave source module includes N parallel microwave output channels, each of which can have its microwave pulse parameters adjusted independently. Taking channel 1 as an example, under the timing control of the nuclear magnetic resonance spectrometer control console, after... After the delay time, the output duration is The microwave pulse width. The duty cycle of the microwave pulse width is determined by... , , It is confirmed that the microwave frequency modulation pulses of each channel can wait for different delay times before being output.

[0098] Specifically, .

[0099] In some embodiments of this example, the microwave pulse parameters also include the scan rate, which is defined as the ratio of the microwave pulse spectral width to the scan time in each channel:

[0100] , (5)

[0101] in, For the first The scan rate of each microwave output channel This refers to the scan time.

[0102] In some embodiments of this example, the scan rate of all microwave output channels should be completed within the electron spin-lattice relaxation time.

[0103] (6)

[0104] in, For electron spin-lattice relaxation time, This refers to the scan rate.

[0105] In some implementations of this embodiment, the scan rate of all microwave output channels needs to meet the thermal adiabatic condition:

[0106] (7)

[0107] in, It is the electronic Rabi frequency.

[0108] Thus, broadband excitation is achieved within the EPR linewidth through multi-channel parallel processing. By optimizing microwave pulse parameters such as the spacing between adjacent microwave output channels, microwave pulse spectral width, microwave pulse spectral amplitude, microwave pulse power, microwave pulse delay time, and scan rate, the excitation efficiency can be improved and the scan time shortened, while further enhancing the NMR signal-to-noise ratio.

[0109] In some embodiments of this example, a combined microwave pulse generated by a combiner is fed into the nuclear magnetic resonance probe through a first isolator. Subsequently, an RF pulse amplified by an RF power amplifier is applied to excite the target nucleus. The nuclear magnetic resonance signal (NMR) is acquired via a control console, and the enhancement factor is calculated according to constraint formula (8). By continuously optimizing microwave pulse parameters, we can obtain nuclear magnetic resonance (NMR) signals with higher signal-to-noise ratios.

[0110] Enhancer Defined as the ratio of the nuclear magnetic resonance signal intensity after combined microwave pulse irradiation to the nuclear magnetic resonance signal intensity in thermal equilibrium:

[0111] (8)

[0112] in, The intensity of the nuclear magnetic resonance signal after being irradiated by a combination of microwave pulses. The intensity of the nuclear magnetic resonance signal is in thermal equilibrium.

[0113] In summary, dynamic nuclear polarization can transfer highly polarized electrons to the target nucleus, significantly enhancing the nuclear magnetic resonance (NMR) signal and improving its signal-to-noise ratio. One method for obtaining highly polarized electrons is through microwave irradiation at frequencies matching electron energy level transitions. Free radicals, as carriers of electron spin, can provide a large number of unpaired electrons, resulting in resonant transitions after microwave irradiation at a specific frequency. However, due to potential inhomogeneities in the main magnetic field and the anisotropy of the free radical's g-factor, its EPR spectrum typically exhibits non-uniform broadening. Theoretically, electron spins across the entire EPR spectrum can participate in the polarization process; however, using a single-frequency microwave irradiation can only excite resonant transitions near that frequency, resulting in low excitation efficiency and a tendency for electron spin polarization to saturate, leading to severe microwave power redundancy.

[0114] Microwave modulation pulses were designed based on testing requirements. Frequency modulation pulses have a certain spectral width. Compared with single-frequency microwave pulses, a certain excitation bandwidth can excite more electron resonant transitions. Although this can further improve excitation efficiency and increase the signal-to-noise ratio of nuclear magnetic resonance (NMR) signals, the frequency scan rate cannot be too fast due to the limitation of adiabatic conditions. Therefore, it inevitably prolongs the single experiment time, and it is difficult to excite all electron spins in a single scan. The utilization rate of electron spins within the EPR spectral width is still not high.

[0115] The multi-channel parallel broadband microwave modulation polarization enhancement method developed in this embodiment effectively solves the problems of long scan time and low excitation efficiency. By using multi-channel parallel broadband microwave frequency modulation pulses and appropriately adjusting the microwave pulse parameters, theoretically, electron spins throughout the entire EPR spectrum can participate in the polarization process, achieving full electron spin polarization within a single scan time. This improves excitation efficiency, shortens experimental time, and significantly enhances the NMR signal-to-noise ratio.

[0116] According to a third aspect of this application, this embodiment provides a computer-readable storage medium having a computer program stored thereon, the computer program including executable instructions that, when executed by a processor, implement the method described above.

[0117] The present invention can implement all or part of the processes in the above methods, or it can be accomplished by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content contained in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0118] According to a fourth aspect of this application, an electronic device is provided, comprising:

[0119] One or more processors;

[0120] Memory is used to store executable instructions for the processor, which, when executed by one or more processors, cause one or more processors to implement the methods described above.

[0121] Electronic devices are manifested in the form of general-purpose computing devices. Components of an electronic device may include, but are not limited to: at least one processor, at least one memory, and a bus connecting different device components (including memory and processor).

[0122] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the computer device, connecting all parts of the computer device through various interfaces and lines.

[0123] Memory can be used to store computer programs and / or modules. The processor implements various functions of the computer device by running or executing the computer programs and / or modules stored in the memory, and by accessing data stored in the memory. Memory can primarily include a program storage area and a data storage area. The program storage area stores application programs required for operating the device and at least one function (e.g., sound playback, image playback, etc.); the data storage area stores data created based on the use of the mobile phone (e.g., audio data, video data, etc.). Furthermore, memory can include high-speed random access memory, and can also include non-volatile memory, such as hard disks, RAM, plug-in hard disks, SmartMedia Cards (SMC), Secure Digital (SD) cards, Flash Cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0124] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus, servers, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and memory) containing computer-usable program code.

[0125] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (devices), servers, and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0126] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0127] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0128] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0129] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0130] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-channel parallel broadband microwave modulation polarization enhancement device, characterized in that, include: Nuclear magnetic resonance spectrometer, including microwave source, nuclear magnetic resonance probe, radio frequency power amplifier and control console; The EPR spectrometer is used to detect the EPR line shape of the free radical sample and obtain the EPR linewidth. Based on the EPR linewidth, the number of parallel microwave output channels to be used is determined. Based on the number of microwave output channels and the EPR linewidth, the microwave pulse parameters output by each microwave output channel are set respectively. The microwave pulse parameters include the interval between adjacent microwave output channels, microwave pulse spectral width, microwave pulse spectral amplitude, microwave pulse power, and microwave pulse delay time. The microwave source includes a signal generation module, multiple parallel microwave output channels, and a combiner. The signal generation module is electrically connected to the multiple parallel microwave output channels, and each of the multiple parallel microwave output channels is electrically connected to the combiner. The multiple parallel microwave output channels are used to output one or more microwave pulses respectively, and the combiner is used to combine one or more microwave pulses to generate a combined microwave pulse with wide spectrum characteristics. The nuclear magnetic resonance probe is electrically connected to the combiner; The radio frequency power amplifier is electrically connected to the nuclear magnetic resonance probe; The control console is connected to the microwave source and the radio frequency power discharge respectively; Through a dynamic nuclear polarization process, the nuclear magnetic resonance probe is used to irradiate the free radical sample with combined microwave pulses, thereby exciting the unpaired electrons in the free radical sample to resonate and transition. The high electron spin polarization is transferred to the target nucleus through the coupling between electrons and nuclei. The radio frequency power amplifier is used to amplify the radio frequency pulse power to excite the target nucleus. The control console acquires the nuclear magnetic resonance signal.

2. The multi-channel parallel broadband microwave modulation polarization enhancement device according to claim 1, characterized in that: The console controls the microwave source module via a first TTL signal, the console controls the radio frequency power amplifier via a second TTL signal, and the console acquires the nuclear magnetic resonance signal.

3. The multi-channel parallel broadband microwave modulation polarization enhancement device according to claim 2, characterized in that, Also includes: A first isolator is disposed between the combiner and the nuclear magnetic resonance probe; A second isolator is disposed between the radio frequency power amplifier and the nuclear magnetic resonance probe.

4. A multi-channel parallel broadband microwave modulation polarization enhancement method, characterized in that, include: The EPR line shape of the free radical sample used was detected using an EPR spectrometer, and the EPR linewidth was obtained. The number of parallel microwave output channels to be used is determined based on the EPR linewidth. Based on the number of microwave output channels and the EPR linewidth used, the microwave pulse parameters output by each microwave output channel are set respectively. The microwave pulse parameters include the interval between adjacent microwave output channels, microwave pulse spectrum width, microwave pulse spectrum amplitude, microwave pulse power, and microwave pulse delay time. A specific frequency microwave pulse is generated by a signal generation module, and then the microwave pulses are output separately through each microwave output channel. All microwave pulses are combined by a combiner to generate a combined microwave pulse with wide spectrum characteristics. The combined microwave pulses are fed into the nuclear magnetic resonance probe. Through a dynamic nuclear polarization process, the nuclear magnetic resonance probe irradiates the free radical sample with the combined microwave pulses, exciting the unpaired electrons of the free radical sample to resonantly transition. Through the coupling between electrons and nuclei, the high electron spin polarization of the free radical sample is transferred to the target nucleus. The target nucleus is excited by amplifying the power of the radio frequency pulse through a radio frequency power amplifier, and the nuclear magnetic resonance signal is collected by the control console.

5. The multi-channel parallel broadband microwave modulation polarization enhancement method according to claim 4, characterized in that: The microwave pulse parameters include the interval between adjacent microwave output channels, microwave pulse spectral width, microwave pulse spectral amplitude, microwave pulse power, and microwave pulse delay time, wherein... The formula for calculating the interval between adjacent microwave output channels is: in, The interval between adjacent microwave output channels For EPR line width, This refers to the number of microwave output channels. The spectral linewidth is mediated by hyperfine interactions; The microwave pulse spectral width satisfies: ， in, For the first The microwave pulse spectrum width of each microwave output channel; The formula for calculating the amplitude of the microwave pulse spectrum is as follows: in, This is the center frequency of the microwave spectrum currently output by this microwave output channel. The amplitude of the microwave pulse spectrum. The center frequency of the microwave spectrum EPR spectral amplitude at the location; The formula for calculating the microwave pulse power is as follows: in, For the first Microwave pulse power of each microwave output channel This represents the channel power at the maximum value of the EPR spectral line. For the first EPR spectrum integral of the range covered by each microwave output channel The integral of the EPR spectrum is the range covered by the microwave output channel corresponding to the maximum value of the EPR spectral line.

6. The multi-channel parallel broadband microwave modulation polarization enhancement method according to claim 4, characterized in that: The microwave pulse parameters also include the scan rate, which is calculated using the following formula: ， in, For the first The scan rate of each microwave output channel This refers to the scan time. The scanning rate satisfies: in, For electron spin-lattice relaxation time, For scan rate; At the same time, insulation conditions must be met: in, It is the electronic Rabi frequency.

7. The multi-channel parallel broadband microwave modulation polarization enhancement method according to claim 4, characterized in that, Also includes: Obtain enhancement factor The calculation formula is: in, The intensity of the nuclear magnetic resonance signal after being irradiated by a combination of microwave pulses. The intensity of the nuclear magnetic resonance signal is in thermal equilibrium.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, The computer program includes executable instructions that, when executed by a processor, implement the method described in any one of claims 4-7.

9. An electronic device, characterized in that, include: One or more processors; A memory for storing executable instructions of the processor, which, when executed by the one or more processors, cause the one or more processors to perform the method of any one of claims 4-7.

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