Device for researching ultrasonic radiation force driven particle motion and control method

Abstract

The invention relates to the technical field of ultrasonic radiation force, in particular to a device for researching particle motion driven by ultrasonic radiation force and a control method. The device comprises a flashboard lifting mechanism, a flashboard assembly, a feedback control module, a transparent container assembly, a probe, a microscope and a high-speed camera, the invention aims to observe the influence of ultrasonic radiation force on particle movement under a microscope through a container containing a medium and providing an observation window. The device can meet basic experiment requirements, has certain flexibility, is more convenient, and can be used for observing the particle motion track at low cost under different ultrasonic conditions. Through the simple design, how the ultrasonic radiation force affects the movement of the particles can be directly observed, and particularly, the movement change of the particles can be tracked in real time in an experiment. The device provides a basic platform for further research on ultrasonic radiation force, is simpler and easier to use in experimental setting, can remarkably reduce the cost burden of the test, and promotes scientific research.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic radiation force, and in particular to a device for studying ultrasonic radiation force driven particle motion and a control method. Background Art

[0002] At present, the technology for observing the influence of ultrasonic radiation force on particle motion mainly relies on several particle motion observation and measurement technologies. Microparticle image velocimetry (μPIV) technology is one of them. It uses a high-speed camera and microscope system to capture the motion trajectory of particles in the fluid in real time, and can accurately measure the velocity and acceleration of particles. It is particularly suitable for the study of particle motion under the action of ultrasound. Dynamic ultrasound scattering (DSS) technology is also a commonly used method. It uses the principle of ultrasonic scattering to monitor the motion of particles by analyzing the changes in the scattering signal of particles in the sound field. It is particularly suitable for high-concentration or turbid media, and does not rely on optical observation. Therefore, it has advantages in application in opaque media. In addition, ultrasonic mechanical measurement is also an effective method. By measuring the displacement data of particles and combining with ultrasonic radiation force theory (such as Gor'kov's theory), the size and distribution of acoustic radiation force on particles can be inferred. These technologies are usually combined with numerical simulation and experimental data analysis to accurately capture the dynamic behavior of particles in the ultrasonic field, help researchers understand the influence of different ultrasonic parameters (such as frequency, power density and duty cycle) on particle motion, and provide theoretical support and experimental basis for ultrasonic particle manipulation. The above-mentioned existing technologies are highly sensitive to ultrasonic parameters (frequency, power) and medium characteristics (density, viscosity), and require strict control of environmental variables; the dynamic response is insufficient, and it is difficult to provide real-time feedback and control of the ultrasonic field (such as quickly adjusting the acoustic tweezers array).

[0003] Ultrasound has radiation force and acoustic streaming effect, which can drive liquid or particles to achieve directional movement. It has important application value in drug delivery, particle manipulation and biophysical experiments. However, to accurately observe the influence of ultrasonic radiation force on particle motion, especially to quantitatively analyze this process, it is still necessary to design a set of precise and controllable experimental devices. At present, there is no special device on the market that can effectively observe the influence of ultrasonic radiation force on particle motion, especially a device that can provide dynamic observation of particles under real-time adjustment of ultrasonic parameters. Most of the existing equipment only provides static observation, or is limited to experiments under fixed ultrasonic parameters, and lacks flexible control of multiple parameters such as ultrasonic frequency and power density. At the same time, the existing devices also lack integrated design, and most experiments rely on multiple distributed systems, such as ultrasonic transducers, microscopes, data recorders, etc., which makes the experimental process more complicated and difficult to perform dynamic observation of multiple ultrasonic conditions on the same platform at the same time.

[0004] Based on the above problems, a portable device combining the complementary advantages of optics, acoustics, and mechanics is proposed to observe the influence of ultrasonic radiation force on particle motion under a microscope through a container that holds a medium and provides an observation window. This device can meet basic experimental needs and has a certain degree of flexibility. It is more convenient and can observe the trajectory of particle motion under different ultrasonic conditions at a low cost. Summary of the invention

[0005] The purpose of the present invention is to address the problems existing in the background technology and to propose a device and a control method for studying the motion of particles driven by ultrasonic radiation force.

[0006] The technical solution of the present invention, the first aspect of the present invention provides a device for studying ultrasonic radiation force driven particle motion, comprising a gate lifting mechanism, a gate assembly, a feedback control module, a transparent container assembly, a probe, a microscope and a high-speed camera; The gate lifting mechanism is used to control the lifting and lowering of the gate assembly; The transparent container assembly is used to contain the particle suspension and form a viewing area for conveniently observing the movement of the particles; The probe is used to transmit ultrasonic waves to the transparent container component, and can adjust the propagation direction and intensity of the ultrasonic waves to provide different ultrasonic conditions; A microscope and a high-speed camera are combined to form an image acquisition system, which is installed at the microscope observation platform of the particle motion device to capture the motion trajectory of particles in the transparent container assembly through a transparent observation window; The feedback control module is used to control the synchronous operation between the gate lifting mechanism, the probe and the high-speed camera; By observing the particle's motion trajectory and based on the particle's motion time and liquid resistance, the radiation force on the particle can be calculated.

[0007] Furthermore, the feedback control module, the transparent container assembly, the microscope and the high-speed camera are all directly mounted on the frame of the particle motion device, the gate assembly is first mounted on the screw of the gate lifting mechanism, and then the gate lifting mechanism is fixed to the transparent container assembly, and the screw is adjusted to ensure that the gate is at the lower limit position.

[0008] Furthermore, the gate lifting mechanism includes a bracket, a limit switch, a motor and a screw rod; The bracket is configured in an L shape, with one end thereof pointing vertically downward being fixed to the frame, and one end thereof extending laterally being located directly above the transparent container assembly; The bracket is provided with holes for fastening and installing the limit switch and the motor in cooperation with the fasteners, and the output shaft of the motor is connected to the lead screw.

[0009] Further, the gate assembly includes a gate, a light shield and a guide rod; Holes are provided on the gate plate for positioning and installing the light baffle and the guide rod.

[0010] Furthermore, the gate lifting mechanism drives the screw rod to move up and down by controlling the forward and reverse rotation of the motor, thereby driving the gate to move up and down; During the movement of the gate, the guide rod passes through the hole reserved on the bracket to guide the gate to prevent displacement; the bottom of the gate is inserted into the cavity of the container of the transparent container assembly; The light shield follows the gate assembly to move up and down, and cooperates with the limit switch to achieve limit at the upper and lower ends.

[0011] Furthermore, the transparent container assembly includes a transparent container, a sound absorbing layer, and a sound-transmitting membrane; a chamber for installing the probe assembly is formed on one side of the container, and the other side is used to contain the particle suspension; a probe fixing rod is provided on one side of the probe assembly, and a hole is reserved on the chamber; the probe fixing rod passes through the hole to position and install the probe assembly; Sound-absorbing layers are arranged all around the container, and a sound-transmitting membrane is arranged on the side facing the installation of the probe assembly; transparent observation windows are reserved on both the upper and lower sides of the container.

[0012] Furthermore, the particle suspension is a mixed solution of 75% water + 25% glycerol.

[0013] Furthermore, the feedback control module calculates the particle response delay and fine-tunes the probe power according to real-time data; the specific feedback control module issues a control instruction to control the gate lifting mechanism to start, and then controls the gate assembly to move up and down. When it reaches the limit switch, it synchronously controls the probe and the high-speed camera to start, and then calculates the particle response delay and calculates the radiation force of the ultrasonic wave; if the calculated radiation force is lower than the threshold, the probe power is increased accordingly to meet the needs of the next experiment.

[0014] A second aspect of the present invention provides a control method for studying an ultrasonic radiation force driven particle motion device, which is used to control the above-mentioned particle motion device, and includes the following specific steps: S1, prepare a particle suspension and add it to the area between the sound-permeable membrane and the gate; S2. Add coupling agent to the other side of the gate, apply coupling agent to the probe, and adjust the probe fixing rod to make the probe close to the sound-transmitting membrane; S3, start the gate lifting mechanism to control the gate to move upward; S4, when reaching the limit switch, the probe and the high-speed camera receive feedback at the same time and start working, and the high-speed camera captures the movement trajectory of the particles; S5. Calculate the ultrasonic radiation force according to the motion trajectory of the captured particles.

[0015] Furthermore, the ultrasonic radiation force is calculated according to the following formula:

[0016] in: is the radius of the particle; is the density of the particle; is the density of the liquid medium; is the acceleration due to gravity; is the viscosity of the liquid; is the velocity of the particle; The relationship between fluid resistance and particle motion: The resistance of the fluid to the particle motion can be calculated by Stokes' law. Given the radius of the particle and the viscosity of the fluid , the resistance of the particle for:

[0017] in, is the velocity of the particle.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects: 1. Real-time dynamic observation capability: Most existing ultrasound experiments are limited to static observation, or can only be performed under fixed ultrasound parameters, lacking continuous observation of particle motion. This scheme designs a set of ultrasonic radiation force driven particle device with a microscope + high-speed camera system, which can capture the particle's motion trajectory, velocity and acceleration in real time at a high frame rate (≥1000 fps), thereby achieving high-time resolution dynamic observation of the impact of ultrasonic radiation force on particle motion.

[0019] 2. Accurate ultrasonic radiation force back-calculation method: Traditional ultrasonic radiation force research usually relies on indirect speculation, while this scheme can combine fluid dynamics models and ultrasonic radiation force calculation formulas to accurately calculate the ultrasonic radiation force on particles by measuring particle velocity, acceleration and liquid resistance, providing quantitative data support for the research on ultrasonic manipulation of microparticles.

[0020] 3. Comprehensive fluid mechanics analysis: This solution not only takes into account the influence of ultrasonic radiation force, but also combines the analysis of fluid viscosity resistance, calculates the force of liquid on particles through the Stokes resistance model, and uses Newtonian mechanics formula to inversely calculate the ultrasonic radiation force, thereby ensuring the accuracy of the calculation. The choice of liquid medium (75% water + 25% glycerol) provides a suitable viscosity, making the force of particles in the sound field closer to the real physiological environment, which is suitable for research in the field of biomedicine.

[0021] 4. Adjustable ultrasonic parameters to meet different experimental needs: This device supports precise adjustment of ultrasonic frequency (1 MHz-3 MHz), power density (0.5-3 W / cm²), and duty cycle (10%-100%). Experimenters can adjust the ultrasonic action conditions according to different research needs, optimize the control and observation of particle motion, and make the experiment more adaptable.

[0022] 5. Integrated experimental platform to improve experimental efficiency: Existing research usually requires the cooperation of multiple independent devices (ultrasonic transducers, microscopes, data acquisition systems), which is cumbersome to operate and difficult to synchronize data. This solution integrates ultrasonic generation, particle motion observation, and data analysis into the same experimental device, and uses a synchronous trigger system to ensure that ultrasonic emission, high-speed camera shooting, and gate opening are carried out simultaneously, reducing data errors and improving the accuracy and repeatability of the experiment.

[0023] 6. The experimental device is simple in structure and easy to operate: This scheme adopts a transparent liquid container + ultrasonic probe + observation window structure design. Compared with the traditional complex experimental platform, it simplifies the operation process, making the experimental device more compact and low-cost, suitable for basic research and experimental teaching. Although the device design is relatively simple, it can provide accurate and reliable ultrasonic radiation force measurement results to meet the needs of basic research, and can be expanded for more complex ultrasonic particle manipulation research. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the overall structure of a particle motion device in an embodiment of the present invention; Figure 2 It is a schematic diagram of the exploded structure of the particle motion device in an embodiment of the present invention; Figure 3 is one of the cross-sectional views of the particle motion device according to an embodiment of the present invention; Figure 4 This is the second cross-sectional view of the particle motion device in the embodiment of the present invention; Figure 5 is a flow chart of a process method in an embodiment of the present invention; Figure 6 It is a particle motion trajectory diagram under the action of high-frequency ultrasound in an embodiment of the present invention; Figure 7 It is a particle motion trajectory diagram under the action of low-frequency ultrasound in an embodiment of the present invention; Figure 8 This is a diagram of particle motion trajectories under the action of dual-frequency ultrasound in an embodiment of the present invention.

[0025] Figure numerals: 1. gate lifting mechanism; 11. motor; 12. bracket; 13. screw rod; 14. limit switch; 2. gate assembly; 21. guide rod; 22. light shield; 23. gate; 3. feedback control module; 4. transparent container assembly; 41. transparent observation window; 42. sound absorbing layer; 43. container; 44. sound-transmitting membrane; 5. microscope; 6. high-speed camera; 7. microscope observation platform; 8. probe assembly; 81. probe fixing rod; 9. particle suspension; 10. coupling agent. DETAILED DESCRIPTION Example 1

[0026] like Figure 1-4 As shown, this embodiment provides a device for studying the motion of particles driven by ultrasonic radiation force, such as Figure 2 As shown, it includes a gate lifting mechanism 1, a gate assembly 2, a feedback control module 3, a transparent container assembly 4, a probe 8, a microscope 5 and a high-speed camera 6; The gate lifting mechanism 1 is used to control the lifting of the gate assembly 2; The transparent container assembly 4 is used to contain the particle suspension 9, forming a viewing area for conveniently observing the movement of the particles; The probe 8 is used to transmit ultrasonic waves to the transparent container assembly 4, and the propagation direction and intensity of the ultrasonic waves can be adjusted to provide different ultrasonic conditions; the probe 8 adopts an ultrasonic transmission system with a frequency range of 1 MHz to 3 MHz, and has an adjustable angle function, which can change the propagation direction and intensity of the ultrasonic waves. The output power range of the probe is 0.5W / cm² to 3W / cm², ensuring that the size of the radiation force can be adjusted according to the experimental requirements.

[0027] The microscope 5 and the high-speed camera 6 are combined to form an image acquisition system, which is installed at the microscope observation platform 7 of the particle motion device, and captures the motion trajectory of the particles in the transparent container assembly 4 through the transparent observation window 41; the transparent observation window 41 ensures the precise installation of the microscope 5 and the high-speed camera, so that the experimenter can observe the motion trajectory of the particles under the action of ultrasound in real time. The frame rate of the high-speed camera is at least 1000 fps, which can capture the subtle motion changes of the particles and facilitate subsequent data analysis.

[0028] The feedback control module 3 is used to control the synchronous operation between the gate lifting mechanism 1, the probe 8 and the high-speed camera 6; the ultrasonic emission is completely synchronized with the trigger system of the high-speed camera to ensure that the action of the ultrasonic wave and the observation of the particle motion are carried out synchronously, so as to obtain accurate experimental data.

[0029] By observing the particle motion trajectory, the radiation force on the particle can be calculated based on the particle motion time and liquid resistance; in this embodiment, the liquid medium is a mixed solution of 75% water + 25% glycerol, and the particles are PS particles with a diameter of 10 μm. The liquid medium has a suitable viscosity and can keep the particles uniformly suspended under the action of ultrasound. The viscosity of the liquid has a certain resistance to the movement of the particles.

[0030] In this embodiment, if Figure 1 As shown, the feedback control module 3, the transparent container assembly 4, the microscope 5 and the high-speed camera 6 are all directly installed on the frame of the particle motion device, the gate assembly 2 is first installed on the screw rod 13 of the gate lifting mechanism 1, and then the gate lifting mechanism 1 is fixed on the transparent container assembly 4, and the screw rod 13 is adjusted to ensure that the gate 23 is at the lower limit position.

[0031] In this embodiment, if Figure 3 As shown, the gate lifting mechanism 1 includes a bracket 12, a limit switch 14, a motor 11 and a screw rod 13; the bracket 12 is arranged in an L shape, and its vertically downward end is fixed on the frame, and its laterally extending end is located directly above the transparent container assembly 4; holes are opened on the bracket 12 for fastening and installing the limit switch 14 and the motor 11 in cooperation with fasteners, and the output shaft of the motor 11 is connected to the screw rod 13.

[0032] In this embodiment, if Figure 3 As shown, the gate assembly 2 includes a gate 23, a light shielding plate 22 and a guide rod 21; the gate 23 is provided with holes for positioning and installing the light shielding plate 22 and the guide rod 21. The gate lifting mechanism 1 drives the screw rod 13 to move up and down by controlling the forward and reverse rotation of the motor 11, and drives the gate 23 to move up and down; during the movement of the gate 23, the guide rod 21 passes through the reserved hole on the bracket 12 to guide the gate 23 to prevent displacement; the bottom of the gate 23 is inserted into the cavity of the container 43 of the transparent container assembly 4; the light shielding plate 22 moves up and down with the gate assembly 2, and cooperates with the limit switch 14 to achieve limit at the upper and lower ends; when the light shielding plate 22 moves to the highest point, it is stuck in the limit switch 14, the laser emitted by the limit switch 14 is blocked, and the limit switch 14 at the bottom cannot receive the laser, that is, it moves to the position, that is, it remains stopped.

[0033] In this embodiment, if Figure 3 As shown, the transparent container assembly 4 includes a transparent container 43, a sound absorbing layer 42, and a sound-transmitting membrane 44; one side of the container 43 forms a chamber for installing the probe assembly 8, and the other side is used to contain the particle suspension 9; a probe fixing rod 81 is provided on one side of the probe assembly 8, and a hole is reserved on the chamber; the probe fixing rod 81 passes through the hole to position and install the probe assembly 8; like Figure 4As shown, sound absorbing layers 42 are arranged around the container 43, and a sound-transmitting membrane 44 is arranged on the side facing the probe assembly 8; transparent observation windows 41 are reserved on the upper and lower sides of the container 43; the transparent observation window 41 at the bottom is used to provide light source for the microscope 5 and the high-speed camera 6.

[0034] Furthermore, the particle suspension 9 is a mixed solution of 75% water + 25% glycerol.

[0035] In this embodiment, a simple container for holding the medium is used, the border is added for sound absorption, and a microscope observation window is reserved, so that liquid media of different concentrations can be held. The container design ensures that the liquid medium can stably suspend particles and provides sufficient optical conditions for particle motion observation under the microscope, avoiding light interference and ensuring clear imaging of particle motion.

[0036] This device uses a synchronous trigger system of an ultrasonic probe and a high-speed camera. The ultrasonic probe is used to generate radiation force to drive the suspended particles; the high-speed camera 6 records the movement trajectory of the particles under the action of ultrasound in real time. Through the synchronous control circuit, the precise coordination of the ultrasonic probe emission, camera operation and gate 23 opening in time is ensured to avoid the influence of delay on the experimental data.

[0037] In the prior art, the scale difference between spatial resolution and theoretical assumptions is specifically: the observation resolution of μPIV is limited by the optical system, particle density and image processing accuracy, and can usually reach the order of several microns; Gor'kov theory assumes that the particle size is much smaller than the wavelength of sound waves (Rayleigh scattering conditions), but the particles actually used in the experiment (such as 10μm) are still "non-minimal" compared to the MHz-level sound wavelength (about 1.5 mm); the scale between the two is not completely matched, resulting in deviations between theoretical and experimental results, especially for non-spherical particles. The fitting problem is more complicated. To address this problem, this embodiment uses a multi-parameter ultrasonic control system: to achieve real-time adjustment of frequency, power density and duty cycle → It helps to optimize the particle response under different experimental conditions, avoid nonlinear effects caused by "too strong sound field", and facilitate the connection between theory and experiment.

[0038] In the prior art, there are problems with the stability and quantitative error of particle tracking. Specifically: in μPIV, if the particles move quickly or aggregate or defocus in the observation window, it is easy to cause the distortion of the velocity vector field; the Gor'kov force field is a time-averaged field, and μPIV measures the instantaneous velocity. How to infer the average force from the instantaneous dynamics requires the introduction of filtering or fitting methods, otherwise there will be a problem of "unstable data". To address this problem, this embodiment uses a synchronous trigger system to achieve "precise time coordination" of the ultrasonic probe, high-speed camera, and gate → It can ensure the consistency of the initial state of the particles and high image time accuracy, which is conducive to the repeatability of PIV data.

[0039] In the prior art, the separation and fitting difficulties under the action of multiple forces are addressed. Specifically, when the actual particles are acted upon by multiple forces simultaneously (such as ultrasonic radiation force, Brownian motion, gravity, fluid resistance, etc.), good control variables (liquid viscosity, temperature, background flow rate) are required to "separately extract" the ultrasonic radiation force component from the μPIV observation; the Gor'kov model does not include fluid viscosity, so it needs to be coupled with the Stokes resistance model. This embodiment uses liquid viscosity design and Stokes resistance correction: a 75% water + 25% glycerol mixture is used to simulate the physiological environment, and the resistance is stable and predictable → the fluid mechanics correction term can be added to the Gor'kov model to improve the accuracy of force inversion.

[0040] In the prior art, there are problems with particle concentration and scattering interference. Specifically, at high particle concentrations, μPIV will cause particle overlap and enhanced light scattering, which will reduce image clarity. Gor'kov force field calculations require that there is no strong interaction between particles, and too dense a density will cause the theory to fail. In this embodiment, real-time high frame rate μPIV capture + force inversion calculation is used: the ultrasonic radiation force can be inferred based on the particle acceleration + fluid resistance model → compared to the traditional "mean displacement method", it has higher accuracy and can be used to verify the theoretical force field distribution. Example 2

[0041] This embodiment provides a control method for studying an ultrasonic radiation force driven particle motion device, and its flow chart is as follows: Figure 5 As shown, the device for controlling the movement of particles in Example 1 includes the following specific steps: S1. Initialize the experimental device and start the self-test; check the device status, and at the same time, the feedback control module 3 detects the status of the probe 8 and records the initial ultrasonic parameters; S2, prepare a particle suspension 9 and add it to the area between the sound-transmitting membrane 44 and the gate plate 23; in step S2, prepare a mixed liquid medium of 75% water + 25% glycerol, add PS particles with a diameter of 10um, mix well and pour into a transparent container 43 to make the particles evenly suspended; and measure the liquid temperature through a sensor to correct the ultrasonic propagation parameters; S3. Add coupling agent 10 to the other side of the gate 23, apply coupling agent 10 on the probe 8, adjust the probe fixing rod 81 to make the probe 8 close to the sound-transmitting membrane 44; synchronously adjust the screw rod to make the gate at the lowest position, and wait for the experiment to start.

[0042] S4, start the gate lifting mechanism 1 to control the gate 23 to move upward; the feedback control module detects the gate position in real time and calculates the movement trajectory; S5, when the limit switch is triggered, the probe and the high-speed camera receive feedback at the same time and start working. The high-speed camera captures the movement trajectory of the particle; the feedback control module calculates the particle response delay and adjusts the probe parameters for the next experiment according to the specific results; S6. Calculate the ultrasonic radiation force according to the motion trajectory of the captured particles.

[0043] Furthermore, the ultrasonic radiation force is calculated according to the following formula:

[0044] in: is the radius of the particle; is the density of the particle; is the density of the liquid medium; is the acceleration due to gravity; is the viscosity of the liquid; is the velocity of the particle; The relationship between fluid resistance and particle motion: The resistance of the fluid to the particle motion can be calculated by Stokes' law. Given the radius of the particle and the viscosity of the fluid , the resistance of the particle for:

[0045] in, is the velocity of the particle.

[0046] Back-calculated radiation force from particle motion: Based on the particle motion data (such as position, velocity, acceleration) and combined with the fluid resistance formula, the ultrasonic radiation force can be back-calculated. The movement of particles in the sound field occurs under the combined force of ultrasonic radiation force and fluid resistance. By measuring the particle's motion trajectory and velocity change, the magnitude of the radiation force on the particle can be inferred, and the distribution of the radiation force can be further calculated.

[0047] After the experiment, the ultrasonic emission is turned off and the motor drives the gate to descend to the initial position. The particle motion data is recorded, and the ultrasonic parameters and experimental conditions are stored. The feedback control module analyzes the experimental error and provides optimization construction.

[0048] In this embodiment, the suspension is prepared by adjusting the size and density of the particles and the density of the liquid medium. The physical properties of the particles (such as size and density) and the viscosity and density of the liquid are accurately calculated to ensure that the particles can be evenly suspended under the action of ultrasound and move stably in the liquid, ensuring the repeatability and reliability of the experimental data.

[0049] The particle's motion trajectory is captured by a high-speed camera, and the ultrasonic radiation force on the particle is calculated by combining the viscosity of the liquid, particle size and other parameters. The radiation force on the particle is calculated by measuring the particle's motion time and liquid resistance, providing data support for further research on the impact of ultrasonic parameters on particle motion.

[0050] By capturing the trajectory and velocity changes of particles, the kinetic model is used to reversely calculate the size of the ultrasonic radiation force. The standard calculation formula of the ultrasonic radiation force is used, combined with experimental data for optimization and adjustment, to ensure accurate quantification of the ultrasonic radiation force under different experimental conditions, and further provide a theoretical basis for the application of ultrasound in physics and medicine. Example 3

[0051] The following uses a specific case to introduce the solution of the present invention in detail: The particle motion observation experiment was carried out using the particle motion device in Example 1 and the control scheme in Example 2: Three frequencies were used, the particle suspension was 22.8g glycerol + 77.3g water + 0.13g Tween-20, the particle concentration was 50mg / ml, the diameter was 10um, and the density was 1.05g / cm 3 The experimental parameters are shown in Table 1. The ultrasonic parameters used were fixed sound intensity of 0.15 W / cm 2 The high frequency part is 2.5M, and the effective radiation area is 7.7cm 2 , duty cycle 10%, current 10A, cycle 10ms, transmission time 8min; low frequency part has a frequency of 0.838M, and an effective radiation area of ​​1.2cm 2 , duty cycle 10%, current 10A, cycle 10ms, emission time 8min; dual frequency means two frequencies are emitted together, each emitting 8min, after the particles are injected and relatively stable for 20s, ultrasonic wave is started. The level meter measures that all the tables are level. The particle movement speed is shown in Table 2-4 below, and the particle movement trajectory is as follows Figure 6-8 shown.

[0052] Table 1 Experimental parameters

[0053] Table 2 Particle movement speed under high-frequency ultrasound

[0054] Table 3 Particle movement speed under low-frequency ultrasound

[0055] Table 4 Particle movement velocity under dual-frequency ultrasound

[0056] The ultrasonic radiation force was calculated using the above observation data according to the steps in Example 2, and the results are shown in the following table: Table 5 Results of radiation force calculated by average velocity at different frequencies

[0057] Through the above experimental analysis, the device and control method can be used to collect particle motion data at low, high and dual ultrasonic frequencies, and by capturing the motion trajectory and velocity changes of the particles, the size of the ultrasonic radiation force can be reversely calculated using a dynamic model. The standard calculation formula for ultrasonic radiation force is used, combined with experimental data for optimization and adjustment, to ensure accurate quantification of ultrasonic radiation force under different experimental conditions, and further provide a theoretical basis for the application of ultrasound in physics and medicine.

[0058] The above embodiments achieve technical innovation in the following aspects: 1. Real-time observation device for particle motion: This device adopts a portable design to accommodate different media and particles. The boundary is treated with sound absorption to reduce the sound wave reflection and echo caused by the hard boundary, thereby avoiding the interference of external or internal noise on the particle motion observation. At the same time, the observation window of the microscope and the particle release gate are reserved. The movement trajectory of particles under the action of ultrasound is accurately recorded with a microscope and a high-speed camera system. The high frame rate of the high-speed camera ensures the fine capture of particle motion, and can accurately obtain the velocity, acceleration and movement path of the particles, thereby providing real-time data support for analyzing the influence of ultrasonic radiation force on particle motion.

[0059] 2. Quantification of ultrasonic radiation force: By processing the experimental data of particle motion, this device can inversely calculate the size and distribution of ultrasonic radiation force. Based on information such as particle acceleration, velocity, and liquid resistance, and using known ultrasonic radiation force calculation formulas, the force exerted by ultrasound on particles can be accurately quantified, providing an accurate experimental basis for the study of ultrasonic radiation force.

[0060] 3. Fluid resistance analysis function: This technical solution combines the characteristics of liquid media to quantitatively analyze the effect of fluid viscosity on particle movement. By measuring the viscosity of the liquid, the size and shape of the particles, the resistance of the fluid to the particles is calculated, thus providing more accurate calculation and analysis of the effect of ultrasonic radiation force.

[0061] 4. Multi-parameter adjustment function: This device supports multi-parameter adjustment of ultrasound, including frequency, power density and duty cycle. This flexible adjustment function allows the experimenter to adjust the working state of ultrasound according to different experimental requirements, optimize the control and observation of particle movement, and adapt to different particle types and experimental conditions.

[0062] 5. The present invention combines the technical means of real-time observation of particle motion, quantification of ultrasonic radiation force, fluid resistance analysis and multi-parameter adjustment, and through precise experimental control and data analysis, realizes the precise observation and quantification of particle motion under the action of ultrasonic radiation force, providing strong technical support for application research in the fields of ultrasonic particle manipulation, drug delivery, etc.

[0063] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto, and various changes can be made within the knowledge scope of technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A device for studying the motion of particles driven by ultrasonic radiation force, characterized in that: It includes a gate lifting mechanism, a gate assembly, a feedback control module, a transparent container assembly, a probe, a microscope and a high-speed camera; The gate lifting mechanism is used to control the lifting and lowering of the gate assembly; The transparent container assembly is used to contain the particle suspension and form a viewing area for conveniently observing the movement of the particles; The probe is used to transmit ultrasonic waves to the transparent container component, and can adjust the propagation direction and intensity of the ultrasonic waves to provide different ultrasonic conditions; A microscope and a high-speed camera are combined to form an image acquisition system, which is installed at the microscope observation platform of the particle motion device to capture the motion trajectory of particles in the transparent container assembly through a transparent observation window; The feedback control module is used to control the synchronous operation between the gate lifting mechanism, the probe and the high-speed camera; By observing the particle's motion trajectory and based on the particle's motion time and liquid resistance, the radiation force on the particle can be calculated.

2. The device for studying ultrasonic radiation force driven particle motion according to claim 1, characterized in that: The feedback control module, transparent container assembly, microscope and high-speed camera are all directly mounted on the frame of the particle motion device. The gate assembly is first mounted on the screw of the gate lifting mechanism, and then the gate lifting mechanism is fixed to the transparent container assembly, and the screw is adjusted to ensure that the gate is at the lower limit position.

3. The device for studying ultrasonic radiation force driven particle motion according to claim 2, characterized in that: The gate lifting mechanism includes a bracket, a limit switch, a motor and a screw rod; The bracket is configured in an L shape, with one end thereof pointing vertically downward being fixed to the frame, and one end thereof extending laterally being located directly above the transparent container assembly; The bracket is provided with holes for fastening and installing the limit switch and the motor in cooperation with the fasteners, and the output shaft of the motor is connected to the lead screw.

4. The device for studying ultrasonic radiation force driven particle motion according to claim 2, characterized in that: The gate assembly includes a gate, a light baffle and a guide rod; Holes are provided on the gate plate for positioning and installing the light baffle and the guide rod.

5. The device for studying ultrasonic radiation force driven particle motion according to claim 3 or 4, characterized in that: The gate lifting mechanism drives the screw rod to move up and down by controlling the forward and reverse rotation of the motor, thereby driving the gate to move up and down; During the movement of the gate, the guide rod passes through the hole reserved on the bracket to guide the gate to prevent displacement; the bottom of the gate is inserted into the cavity of the container of the transparent container assembly; The light shield follows the gate assembly to move up and down, and cooperates with the limit switch to achieve limit at the upper and lower ends.

6. The device for studying ultrasonic radiation force driven particle motion according to claim 1, characterized in that: The transparent container assembly includes a transparent container, a sound absorbing layer, and a sound-transmitting membrane; a chamber for installing the probe assembly is formed on one side of the container, and the other side is used to contain a particle suspension; a probe fixing rod is arranged on one side of the probe assembly, and a hole is reserved on the chamber; the probe fixing rod passes through the hole to position and install the probe assembly; Sound-absorbing layers are arranged all around the container, and a sound-transmitting membrane is arranged on the side facing the installation of the probe assembly; transparent observation windows are reserved on both the upper and lower sides of the container.

7. The device for studying ultrasonic radiation force driven particle motion according to claim 1, characterized in that: The particle suspension is a mixed solution of 75% water + 25% glycerol.

8. The device for studying ultrasonic radiation force driven particle motion according to claim 1, characterized in that: The feedback control module calculates the particle response delay and fine-tunes the probe power based on real-time data.

9. A control method for studying an ultrasonic radiation force driven particle motion device, used to control the particle motion device according to any one of claims 1 to 8, characterized in that: The specific steps include: S1, prepare a particle suspension and add it to the area between the sound-permeable membrane and the gate; S2. Add coupling agent to the other side of the gate, apply coupling agent to the probe, and adjust the probe fixing rod to make the probe close to the sound-transmitting membrane; S3, start the gate lifting mechanism to control the gate to move upward; S4, when reaching the limit switch, the probe and the high-speed camera receive feedback at the same time and start working, and the high-speed camera captures the movement trajectory of the particles; S5. Calculate the ultrasonic radiation force according to the motion trajectory of the captured particles.

10. The control method for studying the ultrasonic radiation force driven particle motion device according to claim 9, characterized in that: The ultrasonic radiation force is calculated according to the following formula: in: is the radius of the particle; is the density of the particle; is the density of the liquid medium; is the acceleration due to gravity; is the viscosity of the liquid; is the velocity of the particle; the relationship between fluid resistance and particle motion: the resistance of the fluid to the particle motion can be calculated by Stokes' law, given the radius of the particle and the viscosity of the fluid , the resistance of the particle for: in, is the velocity of the particle.

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