Method for rapidly measuring liquid flow velocity based on SERF atom magnetometer

Abstract

The invention discloses a method for rapidly measuring the flow rate of liquid based on an SERF atom magnetometer. A laser system, a polarization maintaining optical fiber, a magnetic shielding barrel, a signal collecting and processing system, a signal transmission line, the SERF atom magnetometer, a silica gel hose, a peristaltic pump, a magnetic film and magnetic particles are included. A magnetic object is added into a silica gel hose and conveyed by liquid, and the liquid is pumped to pass through a detection area above the SERF atom magnetometer under the control of a peristaltic pump. The SERF atom magnetometer responds to a single magnetic field signal of a magnetic object in liquid, the attenuation time and the rotation frequency of the magnetic field signal of the magnetic object are obtained through signal processing, and after calibration is carried out according to the relation of the attenuation signal, the rotation frequency and the liquid flow velocity, rapid measurement of the liquid flow velocity is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of precise measurement of liquid flow rate, and in particular to a method for quickly measuring liquid flow rate based on a SERF atomic magnetometer. Background Art

[0002] Under the guidance of an external magnetic field, magnetic particles can carry drugs to perform directional movement and localized concentration, accurately complete targeted drug delivery, improve drug retention at the target site, and reduce toxic side effects on healthy tissues, opening up a new path for future cancer treatment. With the widespread and in-depth application of magnetic particles in the biomedical field, efficient and accurate monitoring of magnetic particles in fluids has become crucial to optimize the delivery strategy of magnetic particles and provide real-time and accurate feedback information for clinical decision-making.

[0003] Magnetic particles are micro-nano biocompatible spheres made of porous polymer materials as the skeleton, which have the characteristics of high drug loading and low toxicity. However, the magnetic field of a single micro-nano magnetic particle is below 500pT, which is only one hundred thousandth of the earth's magnetic field (50000nT), which makes the detection of magnetic particles extremely challenging. The atomic magnetometer based on spin exchange relaxation free (SERF) is currently the most sensitive magnetic field measurement method, and theoretically can achieve aT-level sensitivity. Miniaturized SERF atomic magnetometers have been successfully applied to the measurement of cardiac and brain magnetism, providing a key measurement technology for the quantitative study of magnetic particles.

[0004] Measuring magnetic particles in fluids can quickly obtain characteristic parameters such as particle magnetic field strength and liquid flow rate. The liquid flow rate will directly affect the targeting efficiency of magnetic particles and is one of the important parameters that determine targeted regulation. The current method of measuring liquid flow rate based on the detection of magnetic particles by SERF atomic magnetometers uses the response time interval of multi-channel magnetometers to magnetic particles. This method achieves contactless measurement of liquid flow rate, but still has the disadvantages of measurement delay and large number of occupied signal channels. In magnetic particle imaging based on SERF atomic magnetometers, the imaging time resolution and the utilization rate of the magnetometer signal channel will be further reduced. Summary of the invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a method for quickly measuring liquid flow rate based on SERF atomic magnetometer, which utilizes the SERF atomic magnetometer to respond to a single magnetic field signal of a magnetic object in the liquid, and obtains the magnetic field signal decay time and rotation frequency of the magnetic object through signal processing. After calibration according to the relationship between the attenuation signal, the rotation frequency and the liquid flow rate, the method can realize the rapid measurement of the liquid flow rate, thereby solving the problems of measurement delay and large number of channel occupancy in the current method.

[0006] The technical solution of the present invention is as follows:

[0007] A method for rapidly measuring liquid flow rate based on a SERF atomic magnetometer, characterized in that it comprises the following steps:

[0008] Step 1, installing a silicone hose on a peristaltic pump to form a circulation loop for pumping liquid, wherein a magnetic object that circulates with the liquid is added to the liquid in the silicone hose;

[0009] Step 2, using a SERF atomic magnetometer measurement system to measure the magnetic field signal of the magnetic object to obtain parameter characteristics of the magnetic field signal;

[0010] Step 3, calibrate and measure the liquid flow rate using the relationship between the magnetic field signal parameter characteristics and the liquid flow rate.

[0011] The magnetic object in step 1 is a magnetic film or magnetic particles.

[0012] The SERF atomic magnetometer measurement system in step 2 includes a SERF atomic magnetometer, which is connected to a laser system via a polarization-maintaining optical fiber, and is connected to a signal acquisition and processing system via a signal transmission line. The SERF atomic magnetometer is located in a magnetic shielding barrel, and the silicone hose passes through the magnetic shielding barrel along the x-axis direction from the through holes on both sides of the magnetic shielding barrel. The SERF atomic magnetometer is located directly below the silicone hose passage section, and the SERF atomic magnetometer measures the magnetic field in the y-axis direction.

[0013] The parameter characteristic in step 2 is the magnetic field signal decay time t of the magnetic film d , or the rotational frequency ω of the magnetic particles.

[0014] Decay time t d It is the time it takes for the magnetic field to decay from its peak value to 1 / e, where e is a natural constant.

[0015] Step 3 includes the following relations:

[0016] Q∝1 / t d

[0017] Where Q is the liquid flow rate.

[0018] Step 3 includes the following relations:

[0019] ω=2Q / πr 3

[0020] Where Q is the liquid flow rate and r is the inner radius of the silicone hose.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The liquid flow rate measurement method implemented by the present invention only needs to use one measurement channel of a miniaturized SERF atomic magnetometer, thereby improving the channel information utilization rate of the SERF atomic magnetometer.

[0023] (2) The liquid flow rate measurement method implemented by the present invention only requires a single response measurement of the magnetic object, and there is no need to arrange the magnetometer array along the motion trajectory, so a flexible and free array design can be performed; the single response time is shorter, and a rapid measurement of the liquid flow rate is achieved.

[0024] (3) The liquid flow rate measurement method implemented by the present invention is compatible with objects that perform translational motion and rotation in the liquid, has good versatility in the measurement, improves the adaptability of the measurement method, and can be applied to different demand scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a schematic diagram of the structure of a SERF atomic magnetometer measurement system involved in a method for rapidly measuring liquid flow rate based on a SERF atomic magnetometer.

[0026] Figure 2 include Figure 2 (a) and Figure 2 (b). Figure 2 (a) is a schematic diagram of the translational motion of a magnetic film in a silicone hose involved in a method for rapidly measuring liquid flow rate based on a SERF atomic magnetometer according to the present invention. Figure 2 (b) is based on Figure 2 (a) Schematic diagram of the measurement results of the magnetic field signal of the magnetic film obtained by the magnetometer using the method of the present invention for quickly measuring the liquid flow rate based on the SERF atomic magnetometer. Figure 2 The horizontal axis of (b) is time (s, scale values ​​are 0, 0.25, 0.5, 0.75, 1), and the vertical axis is the magnetic field magnitude (nT, scale values ​​are -4, -2, 0, 2, 4).

[0027] Figure 3 include Figure 3 (a) and Figure 3 (b). Figure 3 (a) is a schematic diagram of the rotational motion of magnetic particles in a fluid involved in the method for rapidly measuring liquid flow rate based on a SERF atomic magnetometer according to the present invention. Figure 3 (b) is based on Figure 3 (a) Schematic diagram of the measurement results of the magnetic field signal of magnetic particles obtained by the magnetometer using the method of the present invention for quickly measuring the liquid flow rate based on the SERF atomic magnetometer. Figure 3The horizontal axis of (b) is time (s, scale value is 0, 1, 2, 3), and the vertical axis is the magnetic field magnitude (pT, scale value is -10, -5, 0, 5, 10).

[0028] The description of the accompanying drawings is as follows: 1-laser system; 2-polarization-maintaining optical fiber; 3-magnetic shielding barrel; 4-signal acquisition and processing system; 5-signal transmission line; 6-SERF atomic magnetometer (SERF, Spin-Exchange Relaxation-Free, no spin exchange relaxation); 7-silicone hose; 8-peristaltic pump; 9-magnetic film; 10-magnetic particles. DETAILED DESCRIPTION

[0029] Below is the attached figure ( Figure 1-Figure 3 ) and Examples illustrate the present invention.

[0030] Figure 1 The present invention is a schematic diagram of the structure of a SERF atomic magnetometer measurement system involved in a method for rapidly measuring liquid flow rate based on a SERF atomic magnetometer. Figure 2 (a) is a schematic diagram of the translational motion of a magnetic film in a silicone hose involved in a method for rapidly measuring liquid flow rate based on a SERF atomic magnetometer according to the present invention. Figure 2 (b) is based on Figure 2 (a) Schematic diagram of the measurement results of the magnetic field signal of the magnetic film obtained by the magnetometer using the method of the present invention for quickly measuring the liquid flow rate based on the SERF atomic magnetometer. Figure 3 (a) is a schematic diagram of the rotational motion of magnetic particles in a fluid involved in the method for rapidly measuring liquid flow rate based on a SERF atomic magnetometer according to the present invention. Figure 3 (b) is based on Figure 3 (a) Schematic diagram of the measurement result of the magnetic field signal of magnetic particles obtained by the method of the present invention for rapid measurement of liquid flow rate based on SERF atomic magnetometer. Figures 1 to 3 As shown, a method for quickly measuring liquid flow rate based on SERF atomic magnetometer includes the following steps: Step 1, installing a silicone hose 7 on a peristaltic pump 8 to form a circulation loop for pumping liquid, and a magnetic object that circulates with the liquid is added to the liquid in the silicone hose 7; Step 2, using the SERF atomic magnetometer measurement system to measure the magnetic field signal of the magnetic object to obtain the parameter characteristics of the magnetic field signal; Step 3, calibrating and measuring the liquid flow rate using the relationship between the magnetic field signal parameter characteristics and the liquid flow rate.

[0031] The magnetic object in step 1 is a magnetic film 9 or a magnetic particle 10. The SERF atomic magnetometer measurement system in step 2 includes a SERF atomic magnetometer 6, the SERF atomic magnetometer 6 is connected to the laser system 1 through a polarization-maintaining optical fiber 2, the SERF atomic magnetometer 6 is connected to the signal acquisition and processing system 4 through a signal transmission line 5, the SERF atomic magnetometer 6 is located in the magnetic shielding barrel 3, the silicone hose 7 passes through the magnetic shielding barrel 3 along the x-axis direction from the through holes on both sides of the magnetic shielding barrel 3, the SERF atomic magnetometer 6 is located directly below the silicone hose passage section, and the SERF atomic magnetometer 6 measures the magnetic field in the y-axis direction.

[0032] The parameter characteristic in step 2 is the magnetic field signal decay time t of the magnetic film 9 d , or the rotation frequency ω of the magnetic particle 10. t d It is the time it takes for the magnetic field to decay from its peak value to 1 / e, where e is a natural constant.

[0033] Step 3 includes the following relationship: Q∝1 / t d , where Q is the liquid flow rate.

[0034] Step 3 includes the following relationship: ω = 2Q / πr 3 , where Q is the liquid flow rate and r is the inner diameter of the silicone hose.

[0035] The invention discloses a method for rapidly measuring liquid flow rate based on a spin-exchange relaxation-free (SERF) atomic magnetometer, comprising a laser system, a polarization-maintaining optical fiber, a magnetic shielding barrel, a signal acquisition and processing system, a signal transmission line, a SERF atomic magnetometer, a silicone hose, a peristaltic pump, a magnetic film, and magnetic particles. A magnetic object is added to the silicone hose and transmitted by the liquid, and the liquid is pumped through a detection area above the SERF atomic magnetometer under the control of the peristaltic pump. The SERF atomic magnetometer is used to respond to a single magnetic field signal of a magnetic object in the liquid, and the magnetic field signal attenuation time and rotation frequency of the magnetic object are obtained through signal processing. After calibration according to the relationship between the attenuation signal, the rotation frequency and the liquid flow rate, rapid measurement of the liquid flow rate is achieved.

[0036] A method for quickly measuring liquid flow rate based on a SERF atomic magnetometer comprises a laser system, a polarization-maintaining optical fiber, a magnetic shielding barrel, a signal acquisition and processing system, a signal transmission line, a spin-exchange relaxation-free (SERF) atomic magnetometer, a silicone hose, a peristaltic pump, a magnetic film, and magnetic particles.

[0037] The magnetic shielding barrel is a cylinder composed of three layers of Permalloy and one layer of aluminum alloy, which is used to reduce the interference of the earth's magnetic field and the laboratory magnetic field to below 10nT; there is a through hole with a diameter of 25mm on both sides and the central axis of the magnetic shielding barrel.

[0038] The SERF atomic magnetometer is placed at the center of a magnetic shielding barrel; the SERF atomic magnetometer is connected to an external laser system via a polarization-maintaining optical fiber to introduce laser into the SERF atomic magnetometer; the SERF atomic magnetometer is connected to an external signal acquisition and processing system via a signal transmission line to transmit electrical signals, including a heating current, a magnetic field coil current, and an output current of a photodetector of the SERF atomic magnetometer; temperature control and magnetic field compensation of the SERF atomic magnetometer are realized by the signal acquisition and processing system; the SERF atomic magnetometer converts the detected magnetic field changes into electrical signals, and the output electrical signals are acquired by the signal acquisition and processing system.

[0039] The silicone hose is a non-magnetic material, temperature resistant to 200°C, and has an inner diameter at the millimeter level; the silicone hose is installed on a peristaltic pump to form a circulation loop for pumping liquid; the silicone hose passes through the magnetic shielding barrel from the through holes on both sides of the magnetic shielding barrel, and the SERF atomic magnetometer is located directly below the silicone hose.

[0040] The size of the magnetic film is in the millimeter range, and its width is smaller than the inner diameter of the silicone hose. The magnetic film is placed in the silicone hose and transported by liquid. The magnetic film moves in translation through the detection area above the SERF atomic magnetometer to collect the changes in the magnetic field signal responded by the SERF atomic magnetometer.

[0041] The SERF atomic magnetometer detects the change in the magnetic field signal of the translational magnetic film, and uses an algorithm to obtain the time for the signal to decay from a peak value to a size of 1 / e (e is a natural constant), which is used as the magnetic field signal decay time of the magnetic film. The inverse proportional relationship between the decay time and the flow rate is used to calibrate and measure the liquid flow rate.

[0042] The magnetic particles are spherical and have a diameter of micrometers. The magnetic particles rotate in the fluid under the shear force, and the rotation frequency ω of the magnetic particles satisfies the linear relationship ω=2Q / πr 3 , where ω is the rotation frequency of the magnetic particles and r is the inner diameter of the silicone hose.

[0043] The SERF atomic magnetometer measures the change of the magnetic field signal of the magnetic particles; firstly, the signal measured by the SERF atomic magnetometer is detrended to remove the offset generated during the measurement process of the SERF atomic magnetometer; then, the signal is processed by continuous wavelet transform to obtain a wavelet transform time-frequency distribution diagram; the frequency component with the largest wavelet coefficient on the time-frequency distribution diagram is extracted, and the frequency component is used as the measured magnetic particle rotation frequency ω; the linear relationship between the rotation frequency and the flow velocity is used to calibrate and measure the liquid flow velocity.

[0044] refer to Figure 1 As shown, the liquid flow rate measurement system based on SERF atomic magnetometer to detect a single magnetic object includes a laser system 1, a polarization-maintaining optical fiber 2, a magnetic shielding barrel 3, a signal acquisition and processing system 4, a signal transmission line 5, a SERF atomic magnetometer 6, a silicone hose 7, and a peristaltic pump 8.

[0045] The magnetic shielding barrel 3 is a cylinder composed of three layers of permalloy and one layer of aluminum alloy, and is used to reduce the interference of the earth's magnetic field and the laboratory magnetic field to below 10nT. There is a through hole with a diameter of 25mm on both sides and the central axis of the magnetic shielding barrel 3.

[0046] The SERF atomic magnetometer 6 is placed at the center of the magnetic shielding barrel 3. The SERF atomic magnetometer 6 is connected to the external laser system 1 through the polarization-maintaining optical fiber 2 to introduce the laser into the SERF atomic magnetometer 6; the SERF atomic magnetometer 6 is connected to the external signal acquisition and processing system 4 through the signal transmission line 5 to transmit electrical signals, which include the heating current, magnetic field coil current, and photodetector output current of the SERF atomic magnetometer 6. The temperature control and magnetic field compensation of the SERF atomic magnetometer 6 are realized by the signal acquisition and processing system 4, which is an electronic system composed of a computer, a hardware circuit, and a test instrument.

[0047] The SERF atomic magnetometer 6 adopts a pump-detect optical path structure and can achieve better than 10fT / Hz. 1 / 2 The SERF atomic magnetometer 6 converts the detected magnetic field changes into electrical signals, and the signal acquisition and processing system 4 collects the output electrical signals.

[0048] When the SERF atomic magnetometer 6 works in the measurement system, it measures the magnetic field in the y-axis direction.

[0049] The silicone hose 7 is made of non-magnetic material, can withstand a temperature of 200° C., and has an inner diameter of millimeters.

[0050] The silicone hose 7 is installed on the peristaltic pump 8 to form a circulation loop for pumping liquid; the silicone hose 7 passes through the magnetic shielding barrel 3 along the x-axis direction from the through holes on both sides of the magnetic shielding barrel 3, and the SERF atomic magnetometer 6 is located directly below the silicone hose 7.

[0051] The peristaltic pump 8 adjusts the flow rate of the pumped liquid by setting the rotation speed of the pump head.

[0052] The size of the magnetic film 9 is in the order of millimeters.

[0053] The magnetic film 9 is placed in the silicone hose 7. The width of the magnetic film 9 is smaller than the inner diameter of the silicone hose 7 and is transported by the liquid. The magnetic film 9 moves in translation through the detection area above the SERF atomic magnetometer 6, and the collected data are as follows: Figure 2 The magnetic field signal changes shown.

[0054] When the liquid passes over the SERF atomic magnetometer 6 at different flow rates, the decay time detected by the SERF atomic magnetometer 6 is different. The greater the flow rate, the shorter the time it takes for the magnetic film 9 to pass through the detection area above the SERF atomic magnetometer 6, and the smaller the decay time. The flow rate and decay time are inversely proportional. Q∝1 / t d , where Q is the liquid flow rate, t d is the decay time of the detection signal.

[0055] Figure 2 The data acquisition result of the present invention is shown in Figure 2. The SERF atomic magnetometer 6 detects the change of the magnetic field signal of the translational magnetic film, and uses an algorithm to obtain the time for the signal to decay from the peak value to 1 / e, which is used as the magnetic field signal decay time of the magnetic film 9. The results show that the present invention can use the decay time to calibrate and measure the liquid flow rate.

[0056] The magnetic particles 10 are spherical and have a diameter in the micrometer range.

[0057] When the magnetic particles 10 are added to the liquid, the magnetic particles 10 rotate under the shear force in the flow, and the rotation frequency ω of the magnetic particles 10 and the liquid flow rate satisfy the linear relationship ω=2Q / πr 3 , where ω is the rotation frequency of the magnetic particles 10 and r is the inner diameter of the silicone hose 7.

[0058] The magnetic field generated by the magnetic particles 10 also rotates and changes at the same frequency in space. The SERF atomic magnetometer 6 is used to measure the change of the magnetic field signal and collect the following information: Figure 3 signal.

[0059] First, the signal measured by the SERF atomic magnetometer 6 is detrended to remove the offset generated during the magnetometer measurement process. Then, the signal is processed using a continuous wavelet transform to obtain a wavelet transform time-frequency distribution diagram; the frequency component with the largest wavelet coefficient on the time-frequency distribution diagram is extracted and used as the measured rotation frequency ω of the magnetic particle 10.

[0060] By changing the liquid flow rate through the peristaltic pump 8, different rotation frequencies of the magnetic particles 10 are measured. The results show that the present invention can calibrate and measure the liquid flow rate by using the rotation frequency.

[0061] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in the field. It is pointed out here that the above description helps those skilled in the art to understand the invention, but does not limit the protection scope of the invention. Any equivalent replacement, modification and / or simplification of the above description without departing from the essence of the invention falls within the protection scope of the invention.

Claims

1. A method for rapidly measuring liquid flow rate based on SERF atomic magnetometer, characterized in that: The following steps are involved: Step 1, installing a silicone hose on a peristaltic pump to form a circulation loop for pumping liquid, wherein a magnetic object that circulates with the liquid is added to the liquid in the silicone hose; Step 2, using a SERF atomic magnetometer measurement system to measure the magnetic field signal of the magnetic object to obtain parameter characteristics of the magnetic field signal; Step 3, calibrate and measure the liquid flow rate using the relationship between the magnetic field signal parameter characteristics and the liquid flow rate.

2. The method for rapidly measuring liquid flow rate based on SERF atomic magnetometer according to claim 1, characterized in that: The magnetic object in step 1 is a magnetic film or magnetic particles.

3. The method for rapidly measuring liquid flow rate based on SERF atomic magnetometer according to claim 1, characterized in that: The SERF atomic magnetometer measurement system in step 2 includes a SERF atomic magnetometer, which is connected to a laser system via a polarization-maintaining optical fiber, and is connected to a signal acquisition and processing system via a signal transmission line. The SERF atomic magnetometer is located in a magnetic shielding barrel, and the silicone hose passes through the magnetic shielding barrel along the x-axis direction from the through holes on both sides of the magnetic shielding barrel. The SERF atomic magnetometer is located directly below the silicone hose passage section, and the SERF atomic magnetometer measures the magnetic field in the y-axis direction.

4. The method for rapidly measuring liquid flow rate based on SERF atomic magnetometer according to claim 1, characterized in that: The parameter characteristic in step 2 is the magnetic field signal decay time t of the magnetic film d , or the rotational frequency ω of the magnetic particles.

5. The method for rapidly measuring liquid flow rate based on SERF atomic magnetometer according to claim 4, characterized in that: t d It is the time it takes for the magnetic field to decay from its peak value to 1 / e, where e is a natural constant.

6. The method for rapidly measuring liquid flow rate based on SERF atomic magnetometer according to claim 4, characterized in that: Step 3 includes the following relations: Q∝1 / t d Where Q is the liquid flow rate.

7. The method for rapidly measuring liquid flow rate based on SERF atomic magnetometer according to claim 4, characterized in that: Step 3 includes the following relations: ω=2Q / πr 3 Where Q is the liquid flow rate and r is the inner diameter of the silicone hose.

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