High-sensitivity magnetic nanoparticle spectrometer and waveform signal conversion method thereof

Abstract

The present application belongs to the field of magnetic nanoparticle measurement, and particularly relates to a high-sensitivity magnetic nanoparticle spectrometer and a waveform signal conversion method thereof, and aims to solve the problem that the dynamic magnetic characteristics of low-concentration magnetic nanoparticles cannot be quantitatively evaluated in the prior art. The present application comprises a driving module, a switching module, a current sampling module, a band-pass filtering module, a rectifying module, a current control module, a voltage adjustment module, a coil matching module, a coil assembly, a receiving coil signal processing module, a signal acquisition analog block, and a main control calculation module. According to the target current demand, the coil matching module can be flexibly edited, and further, the control signal for driving the coil can be automatically generated according to the matched driving circuit and the target waveform, wherein the data acquisition-processing link can restore the waveform and obtain the original spectrum of the magnetic particles through the built-in calculation steps. At the same time, the current compensation loop contained in the present application can compensate the current error caused by factors such as coil temperature rise, parameter drift of the matching module, and change of the on-resistance of the switching module, so as to ensure the constant output of the target harmonic current.

Description

Technical Field

[0001] This invention belongs to the field of magnetic nanoparticle measurement, specifically relating to a high-sensitivity magnetic nanoparticle spectrometer and its waveform signal conversion method. Background Technology

[0002] Magnetic nanoparticles, as a novel imaging probe, possess high contrast and have been widely applied in magnetic nanoparticle imaging, magnetothermal therapy, nuclear magnetic resonance imaging, and photoacoustic imaging. Magnetic nanoparticle imaging, in particular, relies on the dynamic nonlinear magnetization response of magnetic nanoparticles for imaging and has already found applications in cell tracing, tumor labeling, and vascular imaging, among other biomedical fields. Currently, designing different types of magnetic nanoparticles, such as chain nanoparticles and iron-nickel-doped magnetic nanoparticles, to improve application performance is a hot research topic in the field of magnetic nanoparticles.

[0003] Currently, one of the challenges in the field of magnetic nanoparticle research is the lack of tools for quantitative analysis of the dynamic response of magnetic nanoparticles, making it impossible to evaluate their performance under the dynamic magnetic field of magnetic particle imaging devices. In medical applications, the dosage and concentration of magnetic nanoparticles used are very low, further increasing the difficulty of detection and analysis.

[0004] Therefore, this invention proposes a highly sensitive magnetic particle spectrometer that can quantitatively detect the dynamic magnetization response and magnetic characteristics of magnetic nanoparticles at low concentrations, facilitating the evaluation of the performance of magnetic particles in magnetic nanoparticle imaging applications and further promoting research on the application of magnetic nanoparticles. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, namely the lack of tools for quantitative analysis of the dynamic response of magnetic nanoparticles, the inability to evaluate the performance of magnetic nanoparticles under the dynamic magnetic field of magnetic particle imaging devices, and the problem that the dosage and concentration of magnetic nanoparticles used in medical applications are very low, further increasing the difficulty of detection and analysis, this invention provides a high-sensitivity magnetic nanoparticle spectrometer. The magnetic nanoparticle spectrometer includes a drive module, a switch module, a current sampling module, a current control module, a voltage adjustment module, a coil matching module, a coil assembly, a receiving signal processing module, a signal acquisition module, and a main control computing module.

[0006] The drive module is used to receive waveform data from the main control computing module and convert it into a switch control signal, as well as to monitor the working status of the switch module in real time.

[0007] Driven by the switch control signal, the switch module modulates the DC voltage output by the voltage adjustment module into a set voltage waveform. The set voltage waveform is then input to the excitation coil module of the coil assembly after passing through the current sampling module and the coil matching module.

[0008] The current control module is used to receive the current target command value from the main control calculation module, and perform error adjustment calculation in combination with the current sampling signal output by the current sampling module, and transmit the error adjustment signal to the voltage adjustment module.

[0009] The voltage adjustment module precisely corrects the DC voltage signal output by the voltage adjustment module based on the error adjustment signal, thereby maintaining a constant magnitude of the harmonic current in the working range of the magnetic nanoparticle spectrometer.

[0010] The receiving signal processing module receives the voltage signal from the receiving coil module of the coil assembly, and amplifies the voltage signal, as well as amplifies the higher harmonics generated by the excitation magnetic field to excite the particles.

[0011] The signal acquisition module is used to synchronously sample the excitation coil current signal and the receiving coil voltage signal of the current sampling module and the receiving signal processing module, and then convert them into digital signals and transmit them to the main control computing module.

[0012] In some preferred embodiments, when the working state of the switch module is abnormal, the switch control signal output by the drive module is a cut-off signal, which is used to control the switch module to cut off its operation.

[0013] In some preferred embodiments, the switching module is a switch array composed of thyristor devices.

[0014] In some preferred embodiments, the magnetic nanoparticle spectrometer further includes a bandpass filter module and a rectification module;

[0015] The bandpass filter module and the rectifier module sequentially filter and rectify the current sampling signal from the current sampling module to obtain the filtered and rectified current sampling signal.

[0016] In some preferred embodiments, the precise correction is performed by:

[0017] Based on the error adjustment signal and the DC voltage signal output by the voltage adjustment module, the switching module adjusts the DC voltage output by the voltage adjustment module to a set voltage waveform within a set range;

[0018] The set voltage waveform controls the target harmonic current magnitude of the coil assembly, and the drive module, the switch module, the current sampling module, the current control module, and the voltage adjustment module form a closed-loop current control.

[0019] The closed-loop current control is used to achieve precise correction of current errors.

[0020] In some preferred embodiments, the current error is caused by factors including: coil temperature rise of the coil assembly, parameter drift of the coil matching module, and change in the on-resistance of the switching module.

[0021] In some preferred embodiments, the coil matching module is constructed based on a set voltage waveform and forms a resonant-filter circuit with the excitation coil module of the coil assembly to allow the desired harmonic current to pass through the excitation coil and suppress harmonic currents outside the passband frequency.

[0022] In some preferred embodiments, the coil assembly includes an excitation coil module, a receiving coil module, and a coil frame;

[0023] The coil frame is made of a non-magnetic and non-conductive material, with a through hole for the particle to be detected in the middle. The excitation coil module and the receiving coil module are wound around the coil frame.

[0024] In some preferred embodiments, the excitation coil module is formed by sequentially winding multiple layers of densely wound Litz wire, with the number of coil turns being N1, the number of layers being A1, the thickness being H1 mm, the height being W1 mm, and the inner diameter being R1 mm;

[0025] The receiving coil module is made of multiple layers of tightly wound Litz wire or enameled wire wound sequentially. The number of coil turns is N2, the number of layers is A2, the thickness is H2 mm, the height is W2 mm, and the inner diameter is R2 mm.

[0026] Wherein, N1, N2, A1, A2, H1, H2, W1, W2, R1, R2 are parameters preset by the coil matching module during the construction process based on the set voltage waveform.

[0027] In another aspect, the present invention proposes a method for converting high-sensitivity magnetic nanoparticle waveform signals in a high-sensitivity magnetic nanoparticle spectrometer, the method comprising:

[0028] Step S10: The voltage signal of the receiving coil module output by the receiving signal processing module is transformed to the frequency domain through Fourier transform;

[0029] Step S20: Process the frequency domain signal based on the transfer function of the received signal processing module, and obtain the particle magnetization response signal by inverse Fourier transform to the time domain.

[0030] Step S30: Construct the correspondence between the excitation magnetic field of the excitation coil module of the coil assembly and the magnetization response signal of the particle to obtain the dynamic magnetization curve of the magnetic nanoparticle; transform the particle magnetization response signal to the frequency domain through Fourier transform, and select a set octave point amplitude to obtain the frequency domain response of the magnetic nanoparticle.

[0031] The beneficial effects of this invention are:

[0032] (1) The present invention provides a highly sensitive magnetic particle spectrometer capable of quantitatively evaluating the dynamic magnetic properties of low-concentration magnetic nanoparticles. The system can flexibly edit the coil matching module according to the target current requirement, and further automatically generate control signals to drive the coil based on the matched drive circuit and the target waveform.

[0033] (2) The highly sensitive magnetic particle spectrometer of the present invention includes a current compensation circuit that can compensate for current errors caused by factors such as coil temperature rise, matching module parameter drift, and changes in the on-resistance of the switching module, ensuring a constant target harmonic current output. The included data acquisition and processing stage can reconstruct the waveform and obtain the original spectrum of the magnetic particles through built-in calculation steps.

[0034] (3) The high-sensitivity magnetic nanoparticle spectrometer and its waveform signal conversion method of the present invention make up for the lack of tools for quantitative analysis of the dynamic response of magnetic nanoparticles in the current field of magnetic nanoparticle research, and the inability to evaluate the performance of magnetic nanoparticles under the dynamic magnetic field of magnetic particle imaging equipment.

[0035] (4) The high-sensitivity magnetic nanoparticle spectrometer and its waveform signal conversion method of the present invention can quantitatively evaluate the dynamic magnetization response of magnetic nanoparticles at low concentrations, which facilitates the evaluation of the performance of magnetic particles in magnetic nanoparticle imaging applications and further promotes the research on magnetic nanoparticle applications. Attached Figure Description

[0036] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0037] Figure 1 This is a schematic diagram of the components and signal cross-linking relationships of a high-sensitivity magnetic nanoparticle spectrometer according to the present invention;

[0038] Figure 2 This is a schematic diagram of the coil assembly structure of a high-sensitivity magnetic nanoparticle spectrometer according to the present invention;

[0039] Figure 3 This is a flowchart illustrating a highly sensitive magnetic nanoparticle waveform signal conversion method according to the present invention. Detailed Implementation

[0040] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0042] The present invention provides a high-sensitivity magnetic nanoparticle spectrometer, which includes a driving module, a switching module, a current sampling module, a current control module, a voltage adjustment module, a coil matching module, a coil assembly, a receiving signal processing module, a signal acquisition module, and a main control computing module.

[0043] The drive module is used to receive waveform data from the main control computing module and convert it into a switch control signal, as well as to monitor the working status of the switch module in real time.

[0044] Driven by the switch control signal, the switch module modulates the DC voltage output by the voltage adjustment module into a set voltage waveform. The set voltage waveform is then input to the excitation coil module of the coil assembly after passing through the current sampling module and the coil matching module.

[0045] The current control module is used to receive the current target command value from the main control calculation module, and perform error adjustment calculation in combination with the current sampling signal output by the current sampling module, and transmit the error adjustment signal to the voltage adjustment module.

[0046] The voltage adjustment module precisely corrects the DC voltage signal output by the voltage adjustment module based on the error adjustment signal, thereby maintaining a constant magnitude of the harmonic current in the working range of the magnetic nanoparticle spectrometer.

[0047] The receiving signal processing module receives the voltage signal from the receiving coil module of the coil assembly, and amplifies the voltage signal, as well as amplifies the higher harmonics generated by the excitation magnetic field to excite the particles.

[0048] The signal acquisition module is used to synchronously sample the excitation coil current signal and the receiving coil voltage signal of the current sampling module and the receiving signal processing module, and then convert them into digital signals and transmit them to the main control computing module.

[0049] To more clearly illustrate the high-sensitivity magnetic nanoparticle spectrometer of the present invention, the following description is provided in conjunction with... Figure 1 The modules in the embodiments of the present invention will be described in detail below.

[0050] A high-sensitivity magnetic nanoparticle spectrometer according to a first embodiment of the present invention includes a driving module 1, a switching module 2, a current sampling module 3, a bandpass filtering module 4, a rectification module 5, a current control module 6, a voltage adjustment module 7, a coil matching module 8, a coil assembly 9, a receiving signal processing module 10, a signal acquisition module 11, and a main control computing module 12. Detailed descriptions of each module are as follows:

[0051] The drive module 1 is used to receive waveform data from the main control computing module 12 and convert it into switch control signals, as well as to monitor the working status of the switch module 2 in real time.

[0052] Driven by the switch control signal, the switch module 2 modulates the DC voltage output by the voltage adjustment module 7 into a set voltage waveform. After passing through the current sampling module 3 and the coil matching module 8, the set voltage waveform is input to the excitation coil module 91 of the coil assembly 9.

[0053] The current control module 6 is used to receive the current target command value from the main control calculation module 12, and perform error adjustment calculation in combination with the current sampling signal output by the current sampling module 3, and transmit the error adjustment signal to the voltage adjustment module 7.

[0054] The voltage adjustment module 7 accurately corrects the DC voltage signal output by the voltage adjustment module 7 based on the error adjustment signal, so as to maintain the constant magnitude of the harmonic current in the working range of the magnetic nanoparticle spectrometer.

[0055] The receiving signal processing module 10 receives the voltage signal from the receiving coil module 92 of the coil assembly 9, and amplifies the voltage signal, as well as amplifies the high-order harmonics generated by the excitation magnetic field to excite the particles.

[0056] The signal acquisition module 11 is used to synchronously sample the excitation coil current signal and the receiving coil voltage signal of the current sampling module 3 and the receiving signal processing module 10, and convert them into digital signals before transmitting them to the main control calculation module 12. The signal from the current sampling module 3 is filtered and rectified by the bandpass filter module 4 and the rectifier module 5.

[0057] See Figure 1 and Figure 2 The connection relationships of the components of the high-sensitivity magnetic nanoparticle spectrometer of the present invention are as follows:

[0058] The drive module 1, switch module 2, current sampling module 3, coil matching module 8, coil assembly 9, receiving signal processing module 10, signal acquisition module 11, main control calculation module 12, current control module 6, and voltage adjustment module 7 are connected in sequence. The signal output of the previous module is sent to the input terminal of the next module. Among them, the current sampling module 3 also outputs a signal to the signal acquisition module 11, the main control calculation module 12 also outputs a signal to the drive module 1, the voltage adjustment module 7 also outputs a signal to the switch module 2, the current sampling module 3 also outputs a signal to the bandpass filter module 4, the bandpass filter module 4 outputs a signal to the rectifier module 5, and finally the rectifier module 5 outputs a signal to the current control module 6.

[0059] The high-sensitivity magnetic nanoparticle spectrometer of the present invention also includes a bandpass filter module 5 and a rectification module 5.

[0060] The output signal of the current sampling module 3 is filtered by the bandpass filter module 5, rectified by the rectifier module 5, and then output to the current control module 6.

[0061] The drive module 2 receives waveform data from the main control computing module 12 and converts the waveform data into a switch control signal for controlling the switch module 2 through the internal calculation logic of the main control computing module 12. The drive module 2 is also used to monitor the working status of the switch module 2 in real time.

[0062] When the working state of the switch module 2 is detected to be abnormal, the switch control signal output by the drive module 2 is a cut-off signal. This cut-off signal is used to cut off the output of the switch module 2 to protect the downstream circuit.

[0063] Preferred, see Figure 1 and Figure 2 The switching module 2 is a switching array composed of thyristor devices. Its function is to receive the switching control signal of the driving module 2 and modulate the DC voltage output by the voltage adjustment module 7 into a set voltage waveform. This voltage waveform is a power voltage signal with target harmonics. After the power voltage signal with target harmonics is processed by the current sampling module 3 and the coil matching module 8, it is input to the excitation coil module 91 of the coil assembly 9.

[0064] The current sampling module 3 is connected in series in the excitation coil module 91 of the coil assembly 9. It collects the current value flowing through the excitation coil module 91, converts it into a voltage value, and inputs it into the bandpass filter module 4 and the signal acquisition module 11.

[0065] The bandpass filter module 4 performs bandpass filtering on the voltage signal transmitted by the current sampling module 3. The selection of its passband frequency value depends on the harmonic frequency band of the current that needs to be precisely controlled when the high-sensitivity magnetic nanoparticle spectrometer is working. The filtered voltage signal is then transmitted to the rectifier module 5.

[0066] The rectifier module 5 further rectifies and filters the AC voltage signal from the bandpass filter module 4 to convert it into a DC signal. The magnitude of the DC signal is proportional to the effective value of the harmonic voltage.

[0067] The current control module 6 simultaneously receives the target current command value output by the main control calculation module 12 and the filtered and rectified current sample value output by the rectifier module 5. Through internal error calculation, it transmits the error adjustment signal to the voltage adjustment module 7.

[0068] The voltage adjustment module 7 receives the error adjustment signal output by the current control module 6 and precisely corrects its own output DC voltage signal to maintain a constant magnitude of harmonic current in the working range of the magnetic nanoparticle spectrometer.

[0069] The specific method for precise correction is as follows:

[0070] The magnitude of the target harmonic current of the coil is adjusted by changing the magnitude of the DC voltage supplied to the switching module 2. The drive module 1, switching module 2, current sampling module 3, current control module 6 and voltage adjustment module 7 form a closed-loop current control (when the bandpass filter module 4 and rectifier module 5 are included, these two modules are also included in the closed-loop control). This closed-loop current control is used to achieve accurate correction of current error.

[0071] Factors inducing current errors include the temperature rise of the coil in coil assembly 9, parameter drift of coil matching module 8, and changes in the on-resistance of switching module 2.

[0072] The coil matching module 8 can be flexibly constructed according to the set waveform requirements. That is, its structure can be flexibly adjusted according to the waveform required by the application, without being strictly limited by the application scenario. In practical applications, whatever waveform is needed, that waveform is preset. This waveform can be a sine wave, a square wave, etc., and this invention does not limit it. The coil matching module 8 and the excitation coil module 91 in the coil assembly 9 together form a resonant-filter circuit, thereby ensuring that the required harmonic current can pass through the excitation coil to the maximum extent and suppressing harmonic currents outside the passband frequency.

[0073] Coil assembly 9 includes excitation coil module 91, receiving coil module 92, and coil frame 93.

[0074] The coil frame 93 is made of non-magnetic and non-conductive material, with a through hole for the particle to be detected in the middle. The size of the wire groove of the coil frame 93 is the same as that of the excitation coil module 91 and the receiving coil module 92. The excitation coil module 91 and the receiving coil module 92 are wound on the coil frame 93.

[0075] The excitation coil module 91 is made of multiple layers of tightly wound Litz wire wound sequentially. The number of coil turns of the excitation coil module 91 is N1, the number of layers is A1, the thickness is H1 mm, the height is W1 mm, and the inner diameter is R1 mm.

[0076] The receiving coil module 92 is made of multiple layers of tightly wound Litz wire or enameled wire wound sequentially. The receiving coil module 92 has N2 turns, A2 layers, H2 mm thickness, W2 mm height, and R2 mm inner diameter.

[0077] In actual use, the excitation coil module 91 and the receiving coil module 92 need to be placed coaxially, vertically, and spaced D millimeters apart. The excitation coils of the excitation coil module 91 and the receiving coil module 92 are connected in series with the receiving coil, ensuring that:

[0078] The excitation coils of excitation coil module 91 and receiving coil module 92 have the same winding direction, and after being connected in series, the axial component of the current in the magnetic field generated by the two excitation coils has the same direction.

[0079] The receiving coils of the excitation coil module 91 and the receiving coil module 92 are wound in opposite directions, and after being connected in series, the axial components of the magnetic field generated by the current in the two receiving coils are in opposite directions.

[0080] In the above structure, parameters N1, N2, A1, A2, H1, H2, W1, W2, R1, R2, and D are parameters preset by the coil matching module 8 during the construction process based on the set voltage waveform. These parameters are preset by the coil assembly to achieve a higher received signal. The selection of these parameters affects the magnitude of the received signal generated by the receiving coil, and in this invention, a larger signal is preferred.

[0081] In one embodiment of the present invention, N1 = 100, A1 = 10, H1 = 35mm, W1 = 40mm, R1 = 13mm, N2 = 100, A2 = 10, H2 = 7mm, W2 = 10mm, R2 = 6mm, and D = 10cm.

[0082] The receiving signal processing module 10 acquires the voltage signal from the receiving coil module 92 and amplifies the voltage signal generated by the coil through a low-noise amplifier circuit. The receiving signal processing module 10 has a sufficiently high common-mode rejection ratio, thereby suppressing the common-mode voltage and amplifying the differential-mode voltage.

[0083] Meanwhile, the magnetic field receiving circuit composed of the signal processing module 10 and the receiving coil module 92 can bandpass amplify the high-order harmonics generated by the particles excited by the excitation magnetic field, and can attenuate the low-frequency 50Hz power frequency signal and its harmonics, as well as the high-frequency harmonics generated by the operation of the switching circuit.

[0084] The signal acquisition module 11 synchronously samples the excitation coil current signal and the receiving coil voltage signal of the current sampling module 3 and the receiving signal processing module 10, and converts them into digital signals before transmitting them to the main control calculation module 12.

[0085] The main control calculation module 12 outputs the current setpoint and waveform data to the current control module 6 and the drive module 2 respectively, so as to generate the desired waveform in the coil. Here, the desired waveform can be any waveform, which can be selected according to the actual application scenario. This invention does not impose specific waveform restrictions.

[0086] See Figure 3 The second embodiment of the present invention provides a method for converting high-sensitivity magnetic nanoparticle waveform signals in a high-sensitivity magnetic nanoparticle spectrometer, the method comprising:

[0087] Step S10, Data Transformation: The voltage signal of the receiving coil module output by the receiving signal processing module is transformed to the frequency domain through Fourier transform;

[0088] Step S20, Data Correction: Based on the transfer function of the received signal processing module, the frequency domain signal is processed and then converted to the time domain through inverse Fourier transform to obtain the particle magnetization response signal;

[0089] Step S30, Time-domain analysis of magnetization curve: Construct the correspondence between the excitation magnetic field of the excitation coil module of the coil assembly and the magnetization response signal of the particle to obtain the dynamic magnetization curve of the magnetic nanoparticle; Frequency-domain analysis of frequency response: Transform the particle magnetization response signal to the frequency domain through Fourier transform, and select a set octave amplitude to obtain the frequency response of the magnetic nanoparticle.

[0090] The dynamic magnetization curve of magnetic nanoparticles is an indicator of the dynamic magnetization response of magnetic particles. This curve can be used to assess whether magnetic particles are suitable for MPI magnetic nanoparticle imaging and whether they are suitable for fields such as magnetothermal therapy.

[0091] After the Fourier transform, each frequency has an amplitude. This invention only selects the amplitude at frequencies that are multiples of the excitation coil current frequency. For example, if the excitation coil current frequency is 1kHz, then only the amplitude at integer multiples of the frequency, such as 2kHz, 3kHz, 4kHz, etc., is selected. This is the octave amplitude.

[0092] The frequency domain response of magnetic nanoparticles refers to the amplitude at different octave points, which is also an indicator used to evaluate the ability of magnetic particles to generate signals. The higher the octave point amplitude, the stronger the frequency domain response and the better the performance of the magnetic particles in applications.

[0093] The mountain rat waveform conversion method converts the time-domain voltage signal waveform into two indicators: dynamic magnetization curve and frequency domain response, which are used to evaluate the performance of magnetic particles.

[0094] This invention allows for flexible editing of the coil matching module based on target current requirements, and further automatically generates control signals to drive the coil based on the matched drive circuit and the target waveform. Simultaneously, the current compensation circuit included in this invention can compensate for current errors caused by factors such as coil temperature rise, matching module parameter drift, and changes in the switching module's on-resistance, ensuring a constant target harmonic current output. Furthermore, the data acquisition and processing stage included in this invention can reconstruct the waveform and obtain the original spectrum of the magnetic particles through built-in calculation steps.

[0095] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process and related explanations of the methods described above can be found in the corresponding processes in the foregoing system embodiments, and will not be repeated here.

[0096] It should be noted that the high-sensitivity magnetic nanoparticle spectrometer and its waveform signal conversion method provided in the above embodiments are only illustrative examples of the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be further decomposed or combined. For example, the modules in the above embodiments can be merged into one module, or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the various modules or steps and are not considered as an improper limitation of the present invention.

[0097] A device according to a third embodiment of the present invention includes:

[0098] At least one processor;

[0099] and a memory communicatively connected to at least one of the processors;

[0100] The memory stores instructions that can be executed by the processor to implement the above-described method for converting high-sensitivity magnetic nanoparticle waveform signals in a high-sensitivity magnetic nanoparticle spectrometer.

[0101] A computer-readable storage medium according to a fourth embodiment of the present invention stores computer instructions, which are executed by the computer to implement the above-described method for converting high-sensitivity magnetic nanoparticle waveform signals for a high-sensitivity magnetic nanoparticle spectrometer.

[0102] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process and related descriptions of the storage device and processing device described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0103] Those skilled in the art will recognize that the modules and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. The programs corresponding to the software modules and method steps can be placed in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art. To clearly illustrate the interchangeability of electronic hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the invention.

[0104] The terms “first”, “second”, etc., are used to distinguish similar objects, not to describe or indicate a specific order or sequence.

[0105] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such process, method, article, or apparatus / device.

[0106] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A high-sensitivity magnetic nanoparticle spectrometer, characterized in that, The magnetic nanoparticle spectrometer includes a drive module, a switch module, a current sampling module, a current control module, a voltage adjustment module, a coil matching module, a coil assembly, a receiving signal processing module, a signal acquisition module, and a main control computing module. The drive module is used to receive waveform data from the main control computing module and convert it into a switch control signal, as well as to monitor the working status of the switch module in real time. Driven by the switch control signal, the switch module modulates the DC voltage output by the voltage adjustment module into a set voltage waveform. The set voltage waveform is then input to the excitation coil module of the coil assembly after passing through the current sampling module and the coil matching module. The current control module is used to receive the current target command value from the main control calculation module, and perform error adjustment calculation in combination with the current sampling signal output by the current sampling module, and transmit the error adjustment signal to the voltage adjustment module. The voltage adjustment module precisely corrects the DC voltage signal output by the voltage adjustment module based on the error adjustment signal, thereby maintaining a constant magnitude of the harmonic current in the working range of the magnetic nanoparticle spectrometer. The receiving signal processing module receives the voltage signal from the receiving coil module of the coil assembly, and amplifies the voltage signal, as well as amplifies the higher harmonics generated by the excitation magnetic field to excite the particles. The signal acquisition module is used to synchronously sample the excitation coil current signal and the receiving coil voltage signal of the current sampling module and the receiving signal processing module, and then convert them into digital signals and transmit them to the main control computing module. The precise correction includes: Based on the error adjustment signal and the DC voltage signal output by the voltage adjustment module, the switching module adjusts the DC voltage output by the voltage adjustment module to a set voltage waveform within a set range; The set voltage waveform controls the target harmonic current magnitude of the coil assembly, and the drive module, the switch module, the current sampling module, the current control module, and the voltage adjustment module form a closed-loop current control. The closed-loop current control is used to achieve precise correction of current errors.

2. The high-sensitivity magnetic nanoparticle spectrometer according to claim 1, characterized in that, When the working state of the switch module is abnormal, the switch control signal output by the drive module is a cut-off signal, which is used to control the switch module to cut off its operation.

3. The high-sensitivity magnetic nanoparticle spectrometer according to claim 1 or 2, characterized in that, The switching module is a switch array composed of thyristor devices.

4. The high-sensitivity magnetic nanoparticle spectrometer according to claim 1, characterized in that, The magnetic nanoparticle spectrometer also includes a bandpass filter module and a rectifier module; The bandpass filter module and the rectifier module sequentially filter and rectify the current sampling signal from the current sampling module to obtain the filtered and rectified current sampling signal.

5. The high-sensitivity magnetic nanoparticle spectrometer according to claim 1, characterized in that, The current error is caused by factors including: coil temperature rise of the coil assembly, parameter drift of the coil matching module, and change in the on-resistance of the switching module.

6. The high-sensitivity magnetic nanoparticle spectrometer according to claim 1, characterized in that, The coil matching module is constructed based on a set voltage waveform and forms a resonant-filter circuit with the excitation coil module of the coil assembly. This circuit allows the required harmonic current to pass through the excitation coil and suppresses harmonic currents outside the passband frequency.

7. The high-sensitivity magnetic nanoparticle spectrometer according to claim 1, characterized in that, The coil assembly includes an excitation coil module, a receiving coil module, and a coil frame; The coil frame is made of a non-magnetic and non-conductive material, with a through hole for the particle to be detected in the middle. The excitation coil module and the receiving coil module are wound around the coil frame.

8. The high-sensitivity magnetic nanoparticle spectrometer according to claim 7, characterized in that, The excitation coil module is made of multiple layers of tightly wound Litz wire wound sequentially. The number of coil turns is N1, the number of layers is A1, the thickness is H1 mm, the height is W1 mm, and the inner diameter is R1 mm. The receiving coil module is made of multiple layers of tightly wound Litz wire or enameled wire wound sequentially. The number of coil turns is N2, the number of layers is A2, the thickness is H2 mm, the height is W2 mm, and the inner diameter is R2 mm. Wherein, N1, N2, A1, A2, H1, H2, W1, W2, R1, R2 are parameters preset by the coil matching module during the construction process based on the set voltage waveform.

9. A method for converting high-sensitivity magnetic nanoparticle waveform signals in a high-sensitivity magnetic nanoparticle spectrometer, using the high-sensitivity magnetic nanoparticle spectrometer according to any one of claims 1-8, characterized in that, include: Step S10: The voltage signal of the receiving coil module output by the receiving signal processing module is transformed to the frequency domain through Fourier transform; Step S20: Process the frequency domain signal based on the transfer function of the received signal processing module, and obtain the particle magnetization response signal by inverse Fourier transform to the time domain. Step S30: Construct the correspondence between the excitation magnetic field of the excitation coil module of the coil assembly and the magnetization response signal of the particle to obtain the dynamic magnetization curve of the magnetic nanoparticle; transform the particle magnetization response signal to the frequency domain through Fourier transform, and select a set octave point amplitude to obtain the frequency domain response of the magnetic nanoparticle.

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