阅读说明：本技术 一种基于人工结构平板的新型声镊子 (Novel acoustic tweezers based on artificial structure is dull and stereotyped ) 是由 贾雨柔 吴大建 刘晓峻 于 2020-04-24 设计创作，主要内容包括：本发明公开了一种基于人工结构平板的新型声镊子,该技术依赖的操作系统包括三维平移装置、用于辐射超声波的超声波发射装置、人工结构平板和载物台,载物台用于放置待操控颗粒,人工结构平板具有特殊的几何设计,用于调制声场形成多种特殊构型的聚焦花瓣声束,并对不同大小的颗粒进行捕获,三维平移装置用于移动由人工结构平板生成的聚焦花瓣声束,从而实现颗粒的自由传递和运输。该新型声镊子主要利用人工结构平板调制声场产生多种聚焦花瓣声束,应用其声辐射力特性将不同大小的颗粒捕获在声束的中心区域,并通过移动聚焦花瓣声束实现颗粒的传递和运输,该技术在材料制备、细胞分离、药物运输以及生物工程等实际应用方面具有重要研究价值。(The invention discloses a novel acoustic tweezers based on an artificial structure flat plate, and an operating system which is depended by the technology comprises a three-dimensional translation device, an ultrasonic wave emitting device used for radiating ultrasonic waves, the artificial structure flat plate and an object stage, wherein the object stage is used for placing particles to be controlled, the artificial structure flat plate is provided with a special geometric design and is used for modulating a sound field to form focusing petal acoustic beams with various special configurations and capturing the particles with different sizes, and the three-dimensional translation device is used for moving the focusing petal acoustic beams generated by the artificial structure flat plate, so that the particles are freely transferred and transported. The novel acoustic tweezers mainly use an artificial structure flat plate to modulate a sound field to generate various focusing petal acoustic beams, use the acoustic radiation force characteristic to capture particles with different sizes in the central area of the acoustic beams, and realize the transfer and transportation of the particles by moving the focusing petal acoustic beams.)

1. A novel acoustic tweezers based on artificial structure flat plate, the operation system comprises:

a three-dimensional translation device (10) located at the uppermost part of the operation system and used for moving the ultrasonic transducer and the artificial structure flat plate (30);

an ultrasonic wave emitting device (20) located directly below the three-dimensional translation device (10) and including an ultrasonic transducer for radiating planar ultrasonic waves;

the artificial structure flat plate (30) is arranged right below the ultrasonic transducer and is used for modulating a transmission sound field to form focused petal sound beams with various configurations;

the object stage (40) is arranged right below the artificial structure flat plate (30) and is used for placing particles to be controlled;

the artificial structure flat plate (30) is provided with m uniform sectors, each sector is formed by two groups of discrete curve seams which are respectively marked as I and II; the radius of the initial curve seam of I and II is r₀And r₁The radial distance between adjacent seams is g, the width of the seams is d, and the number of the seams is L;

when m is 1, the curve seams of I and II are respectively expressed as: r is_I(θ)＝r₀G, theta is more than or equal to 0 and less than or equal to pi and r_II(θ)＝r₁+(L-1)g，π≤θ≤2π，L＝1,2,…,6；

When m is more than or equal to 2, the curve seams of I and II are respectively expressed as: r is_I(θ)＝r₀G,. pi. (2n-2)/m,. pi.,. theta.,. pi. (2n-2)/m and r_II(θ)＝r₁+(L-1)g，π(2n-1)/m≤θ≤π(2n)/m，L＝1,2,…,6，n＝1,2,…,m；1.5mm≤g≤1.8mm；0.3mm≤d≤0.6mm。

2. The acoustic tweezers of claim 1, wherein the curved slot L-6.

3. Novel acoustic tweezers according to claim 1 or 2, wherein the number of sectors, m-1 or m-5.

4. Novel acoustic tweezers according to any one of claims 1 to 3, characterised in that the initial radius r of the curvilinear slits I and II in said artificial structural plate (30)₀And r₁Certain conditions are met: r is₁＝r₀+g/2；

Preferably, the geometric parameter r₀、r₁G and d were set to 7, 7.85, 1.7 and 0.6mm, respectively.

5. Novel acoustic tweezers according to any one of claims 1 to 4, characterised in that said artificial structural plate (30) has a cylindrical geometry, the diameter and thickness of said artificial structural plate (30) being D and t, respectively; wherein D is more than or equal to 35mm and less than or equal to 64mm, and t is more than or equal to 0.2mm and less than or equal to 3 mm.

Preferably, the initial radius r of the curved slits I and II of the artificial structural flat plate (30)₀And r₁Certain conditions are met: r is₁R0+ g/2; preferably, the geometric parameter r₀、r₁G, D, D and t are respectively set to be 7mm, 7.85mm, 1.7mm and 0.6mm, 35mm and 3 mm.

6. The new acoustic tweezers of any one of claims 1 to 5, wherein said artificial structural slab (30) presents a planar shape at both the entrance face and the exit face;

preferably, the artificial structural flat plate (30) has an acoustic impedance value of 3.5 × 10 or more⁷Ns/m³Is made of a hard material.

Preferably, the artificial structure flat plate (30) is made of stainless steel material, titanium alloy material or brass material; the density, the longitudinal wave velocity and the transverse wave velocity of the stainless steel material are 7900kg/m respectively³5240m/s and 2978 m/s.

7. Novel acoustic tweezers according to any one of claims 1 to 6, wherein said ultrasound emission means (20) comprise a signal generator (21), a power amplifier (22) and an ultrasound transducer (23); the signal generator (21) is used for controlling the waveform and frequency of an output electric signal, the power amplifier (22) is used for increasing incident electric power of the ultrasonic transducer (23), and the ultrasonic transducer (23) is used for radiating plane ultrasonic waves.

8. The new acoustic tweezers of any one of claims 1 to 7, wherein said handling system further comprises an electron microscope (50) and an acoustic absorber, said electron microscope (50) being used to capture and record the process of capturing and moving particles by focused petal acoustic beams; the sound absorber is placed at the bottom of the water tank to reduce the influence of reflected sound waves on a sound field.

Preferably, the sound absorber is a rubber sound absorber; more preferably, the sound absorber is a wedge-shaped rubber sound absorber.

9. Novel acoustic tweezers according to any one of claims 1 to 8, wherein said three-dimensional translation means (10) comprise a high precision electric stage and stage control box for controlling the spatial position of the ultrasound transducer and the artificial structure plate.

10. Acoustic tweezers according to any one of claims 1 to 9, characterised in that the stage (40) is made of a transparent polyethylene petri dish with a material density and sound velocity of 930kg/m, respectively³And 1950 m/s; preferably, the stage (40) has a thickness of 0.8 mm.

Preferably, the particles to be controlled are polystyrene microspheres, and the sound velocity of the polystyrene microspheres is 1050kg/m³The transverse wave velocity was 2170m/s and the longitudinal wave velocity was 1100 m/s.

Preferably, the size of the small-sized polystyrene microspheres is 0.1-2 mm; more preferably 0.1-0.24 mm; the size of the large-size polystyrene microsphere is 1.5-2 mm;

for example, polystyrene microspheres are much smaller in size than the acoustic wavelength, and have a diameter of 0.24 mm; or the size of the polystyrene microsphere reaches the order of wavelength and the diameter of the polystyrene microsphere is 1.5 mm.

Technical Field

The invention belongs to the technical field of sound wave control, and particularly relates to novel acoustic tweezers based on an artificial structure flat plate.

Background

The research and development of the micro-control technology have important significance in the fields of biology, physics, chemistry, medicine and pharmacy and the like. The micromanipulation technology not only provides an important research means for physical and biological characteristics of cells, particles and microorganisms, but also provides related technical support for development of various experimental instruments for manipulating tiny objects. How to design and prepare a control technology with accuracy, reliability, simplicity, convenience and low cost to realize flexible control of tiny objects has become one of the popular research directions.

Compared with micro-control technologies such as an optical field, a magnetic field, electrophoresis, microfluid and the like, the acoustic tweezers have the advantages of low energy loss, small biological damage, deep penetration depth and the like, and have wide application prospects in the aspects of material preparation, cell separation, drug transportation, bioengineering and the like. At present, the implementation method of acoustic tweezers mainly focuses on an active transducer array, that is, a specific phase distribution is obtained by independently controlling the phase delay of each transducer, so as to construct various complex acoustic fields and generate various micro-manipulation modes, such as focusing, separating, clearing, capturing, rotating and the like. However, such transducer array design requires complex circuit regulation and precise phase control; meanwhile, a single transducer has a certain volume size, which will severely limit the effective generation of high-frequency sound field and the manipulation of high-frequency sound waves to tiny objects.

Recently, acoustic tweezers using passive type acoustic artificial structures have attracted extensive attention from researchers. The realization method comprises the steps of designing an artificial structural unit with special properties, flexibly regulating and controlling a sound field by adjusting the configuration and arrangement mode of the structural unit, and further realizing the high-precision micro-control technology by utilizing the sound radiation force characteristic of the sound field. For example, the periodic artificial structure flat plate is used for inducing the enhancement effect of the local sound field, and the particles can be captured, screened, ordered and the like; designing a structural plate with a quasi-periodic acoustic grating engraved on the surface, and realizing the movement and transportation of particles by modulating the working frequency of incident sound waves; recording sound field phase information on the acoustic hologram, and constructing a complex sound field to force particles to move according to a preset track; an acoustic super-surface array is constructed to generate a plurality of special sound beams, so that stable capture and rotary control of tiny objects are realized. The acoustic tweezers based on the artificial structure have the advantages of simple structural design, capability of freely modulating an acoustic field and the like, and provide a new method and thought for controlling particles and biological cells. At present, the method mainly focuses on controlling a tiny object with the size far smaller than the wavelength of sound waves, and the control research on a larger object with the size reaching the magnitude order of the wavelength is not reported yet.

Disclosure of Invention

The invention aims to provide novel acoustic tweezers based on an artificial structure flat plate, which are characterized in that a sound field is modulated by the artificial structure flat plate to form a plurality of focusing petal acoustic beams with special configurations, and the acoustic radiation force characteristics of the acoustic tweezers are used for controlling the capture, transmission, transportation and the like of particles with different sizes.

In order to achieve the above object, according to one aspect of the present invention, there is provided a novel acoustic tweezer based on an artificial structural plate, the operating system of which comprises: the three-dimensional translation device is positioned at the uppermost part of the operating system and is used for moving the ultrasonic transducer and the artificial structure flat plate; the ultrasonic transmitting device is positioned right below the three-dimensional translation device and comprises an ultrasonic transducer for radiating plane ultrasonic waves; the artificial structure flat plate is arranged right below the ultrasonic transducer and used for modulating a transmission sound field to form focused petal sound beams with various configurations; the object stage is arranged right below the artificial structure flat plate and used for placing particles to be controlled; the artificial structure flat plate is provided with m uniform sectors, each sector is formed by two groups of discrete curve seams which are respectively marked as I and II; the radius of the initial curve seam of I and II is r₀And r₁The radial distance between adjacent seams is g, the width of the seams is d, and the number of the seams is L; when m is 1, the curve seams of I and II are respectively expressed as: r is_I(θ)＝r₀G, theta is more than or equal to 0 and less than or equal to pi and r_II(θ)＝r₁G, phi is not more than theta and not more than 2 pi, and L is 1,2, …, 6; when m is more than or equal to 2, the curve seams of I and II are respectively expressed as: r is_I(θ)＝r₀G,. pi. (2n-2)/m,. pi.,. theta.,. pi. (2n-2)/m and r_II(θ)＝r₁+(L-1)g，π(2n-1)/m≤θ≤π(2n)/m，L＝1,2,…,6，n＝1,2,…,m；1.5mm≤g≤1.8mm；0.3mm≤d≤0.6mm。

According to the invention, in the novel acoustic tweezers based on the artificial structural flat plate, the curve slit L is 6.

According to the novel acoustic tweezers based on the artificial structure flat plate, the number m of the sectors is 1 or 5.

According to the invention, the initial radius r of the curved slits I and II in the plate of the artificial structure₀And r₁Certain conditions are met: r is₁＝r₀+ g/2; preferably, the geometric parameter r₀、r₁G and d were set to 7, 7.85, 1.7 and 0.6mm, respectively.

According to the invention, the artificial structural slab has a cylindrical geometry, the diameter and thickness of which are D and t, respectively; wherein D is more than or equal to 35mm and less than or equal to 64mm, and t is more than or equal to 0.2mm and less than or equal to 3 mm. Preferably, the initial radius r of the curved slits I and II in the plate of the artificial structure₀And r₁Certain conditions are met: r is₁R0+ g/2; preferably, the geometric parameter r₀、r₁G, D, D and t are set to 7mm, 7.85mm, 1.7mm, 0.6mm, 35mm and 3mm, respectively.

According to the invention, the artificial structural flat plate has an acoustic impedance value of 3.5 × 10⁷Ns/m³Is made of a hard material. Preferably, the artificial structure flat plate is made of stainless steel materials, titanium alloy materials or brass materials; the density, the longitudinal wave velocity and the transverse wave velocity of the stainless steel material are 7900kg/m respectively³5240m/s and 2978 m/s.

According to the invention, the ultrasonic transmitting device comprises a signal generator, a power amplifier and an ultrasonic transducer; the signal generator is used for controlling the waveform and frequency of an output electric signal, the power amplifier is used for increasing incident electric power of the ultrasonic transducer, and the ultrasonic transducer is used for radiating plane ultrasonic waves.

According to the invention, the operating system also comprises an electron microscope and a sound absorber, wherein the electron microscope is used for shooting and recording the process of capturing and moving particles by the focused petal sound beams; the sound absorber is placed at the bottom of the water tank to reduce the influence of reflected sound waves on a sound field. Preferably, the sound absorber is a rubber sound absorber; more preferably, the sound absorber is a wedge-shaped rubber sound absorber.

According to the invention, the three-dimensional translation device comprises a high-precision electric transfer table and an electric transfer table control box, and is used for controlling the spatial positions of the ultrasonic transducer and the artificial structure flat plate.

According to the invention, the stage is made of a polyethylene transparent culture dish, the material density and the sound velocity of which are 930kg/m respectively³And 1950 m/s; preferably, the thickness of the stage is 0.8 mm.

Preferably, the particles to be controlled are polystyrene microspheres, and the sound velocity of the polystyrene microspheres is 1050kg/m³The transverse wave velocity was 2170m/s and the longitudinal wave velocity was 1100 m/s.

Preferably, the size of the small-sized polystyrene microspheres is 0.1-2 mm; more preferably 0.1-0.24 mm; the size of the large-size polystyrene microsphere is 1.5-2 mm. For example, polystyrene microspheres are much smaller in size than the acoustic wavelength, and have a diameter of 0.24 mm; or the size of the polystyrene microsphere reaches the order of wavelength and the diameter of the polystyrene microsphere is 1.5 mm.

The invention has the beneficial effects that:

1) the invention utilizes an artificial structure flat plate with special design to modulate a sound field to form a plurality of focusing petal sound beams with special configurations, respectively captures particles with different sizes at the mechanical balance position of the petal sound beams, and freely transmits and transports the particles with corresponding sizes by moving the focusing petal sound beams. The control mode can realize the control of tiny objects with the size far smaller than the wavelength of the sound wave, and can also be used for controlling larger objects with the size reaching the magnitude order of the wavelength.

2) The artificial structure flat plate designed by the invention is in a plane shape on the incident surface and the emergent surface, the thickness of the artificial structure flat plate along the propagation direction is not limited, the artificial structure flat plate can be made into an ultrathin circular sheet shape according to the actual requirement, and can also be made into a cylinder shape with a certain thickness, and the artificial structure flat plate has unique advantages in the design and preparation of integrated acoustic devices. In conclusion, the invention provides the novel acoustic tweezers based on the artificial structure flat plate, which are simple to operate, low in cost, accurate and reliable.

Drawings

FIG. 1 is a schematic diagram of an embodiment of the novel acoustic tweezers based on an artificial structural flat plate according to the present invention;

FIG. 2 is a schematic diagram of an experimental device of the novel acoustic tweezers based on the artificial structure flat plate provided by the invention;

FIG. 3 is a schematic structural view of an artificial structural flat plate used in the present invention;

FIG. 4 is an acoustic field diagram of a focused petal acoustic beam with m 1 generated by the artificial structural plate of the present invention;

FIG. 5 is an acoustic field diagram of a focused petal acoustic beam with m-5 produced by the artificial structural plate of the present invention;

FIG. 6 is a diagram of experimental samples, experimental tests and simulated acoustic fields for specific generation of focused petal acoustic beams provided by the present invention;

FIG. 7 is a graph showing the effect of capturing and moving smaller polystyrene microspheres using the novel acoustic tweezers of the present invention;

FIG. 8 is a graph showing the effect of using the novel acoustic tweezers of the present invention to capture and move larger polystyrene microspheres.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings and embodiments. It should be emphasized that the specific embodiments described herein are merely illustrative of the invention, are some, not all, and therefore do not limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

As shown in fig. 1-3, the present invention provides a novel acoustic tweezers based on artificial structure flat plate, the operation system of which comprises a three-dimensional translation device 10, an ultrasonic wave emitting device 20, an artificial structure flat plate 30 and an object stage 40. Wherein, the three-dimensional translation device 10 is located at the top of the operation system and used for moving the ultrasonic transducer and the artificial structure flat plate 30, and the three-dimensional translation device is used for moving the focused petal sound beam generated by the artificial structure flat plate, thereby flexibly moving and transporting particles with different sizes and realizing the free transfer and transportation of the particles. The ultrasonic wave emitting device 20 is located directly below the three-dimensional translation device 10, and includes an ultrasonic transducer for radiating planar ultrasonic waves. The artificial structure flat plate 30 is arranged right below the ultrasonic transducer, has a special geometric design, and is used for modulating a transmission sound field to form a plurality of focusing petal sound beams with special configurations and capturing particles to be controlled in different sizes. The stage 40 is disposed directly below the artificial structure plate 30 for placing particles to be manipulated.

According to the invention, the artificial structural slab has a cylindrical geometry with a diameter and thickness D and t, respectively. Preferably, D is more than or equal to 35mm and less than or equal to 64mm, and t is more than or equal to 0.2mm and less than or equal to 3 mm. The artificial structure flat plate is uniformly divided into m sectors, each sector is formed by two groups of discrete curve seams which are respectively marked as I and II; the radius of the initial curve seam of I and II is r0 and r1 respectively, the radial distance between adjacent seams is g, and the width of the seam is d; when m is 1, the curve seams of I and II are respectively expressed as: r is_I(theta) ═ r0+ (L-1) g, 0. ltoreq. theta.ltoreq.pi and r_II(θ)＝r₁G, phi is not more than theta and not more than 2 pi, and L is 1,2, …, 6; when m is more than or equal to 2, the curve seams of I and II are respectively expressed as: r is_I(θ)＝r₀G,. pi. (2n-2)/m,. pi.,. theta.,. pi. (2n-2)/m and r_II(θ)＝r₁+(L-1)g，π(2n-1)/m≤θ≤π(2n)/m，L＝1,2,…,6，n＝1,2,…,m。

The novel acoustic tweezers based on the artificial structure flat plate are based on the principle of acoustic wave diffraction action and the initial radius r of the curve seams of the I curve and the II curve₀And r₁Certain conditions are met: r is₁＝r₀+ g/2; its geometric parameter r₀、r₁G and d were set to 7, 7.85, 1.7 and 0.6mm, respectively.

In the novel acoustic tweezers based on the artificial structure flat plate, the artificial structure flat plate 30 is in a planar shape on the incident surface and the emergent surface. The thickness t of the film along the propagation direction is not limited, and the film can be made into an ultrathin disc shape according to actual requirements and also can be made into a cylinder shape with a certain thickness.

According to the present invention, the artificial structural flat plate 30 may be made of a stainless material, a titanium alloy material, or a brass material. Preferably, the artificial structural flat plate 30 is prepared from a stainless steel materialThe density, the longitudinal wave velocity and the transverse wave velocity are 7900kg/m respectively³5240m/s and 2978m/s, with acoustic impedances approximately 20 times that of the background medium the present invention is preferably, but not limited to, stainless steel, other rigid materials with sufficient acoustic impedance may also be used to form the artificial structural panel, preferably, the material used for the artificial structural panel 30 has an acoustic impedance value generally equal to or greater than 3.5 × 10⁷Ns/m³。

As shown in fig. 2, the ultrasonic wave emitting device 20 of the novel acoustic tweezers based on the artificial structural flat plate comprises a signal generator 21, a power amplifier 22 and an ultrasonic transducer 23. The signal generator 21 is used to control the waveform and frequency of the output electrical signal, the power amplifier 22 is used to increase the incident electrical power of the ultrasonic transducer 23, which is used to emit planar ultrasonic waves. The ultrasonic transducer 23(DYG-1M, Dayu Electric, China) has a diameter of 6.4cm and a center frequency of 1 MHz; the transmission signal of the signal generator 21(AFG3021, Tectronix) is a continuous sinusoidal signal with an operating frequency of 1 MHz; the continuous sinusoidal signal passes through the power amplifier 22(325LA, ENI) and excites the ultrasonic transducer 23 to generate a planar ultrasonic wave. The signal generator 21 is used for generating a sinusoidal electric signal with the frequency of 1MHz, the electric signal is input into the power amplifier 22 through a cable, the amplification factor of the power amplifier 22 is modulated to effectively improve the output electric power of the electric signal, and the electric signal is further input into the ultrasonic transducer 23 to generate a plane wave with the frequency of 1 MHz.

In the above operating system, the three-dimensional translation device 10 is mainly a three-dimensional manual fine adjustment high precision displacement table. The ultrasonic transducer 23 and the artificial structure flat plate 30 are fixed on the displacement table by utilizing the support rod, and the three-dimensional space positions of the ultrasonic transducer 23 and the artificial structure flat plate 30 can be freely controlled by manually rotating the knob of the displacement table according to the actual displacement requirement.

According to the invention, the stage 40 has a thickness of about 0.8mm, and may be made of a polyethylene transparent petri dish, with a material density and a sound velocity of 930kg/m, respectively³And 1950 m/s. The background medium is water, and the density and the sound velocity of the water are respectively 1000kg/m³And 1490 m/s. The acoustic impedance of polyethylene is similar to that of water, so that the stage 40 may be submergedTo be viewed as an acoustically transparent material that reflects sound waves with little effect on the overall distribution of the sound field.

According to the invention, the particles to be manipulated can be polystyrene microspheres with an acoustic velocity of 1050kg/m³The transverse wave velocity was 2170m/s and the longitudinal wave velocity was 1100 m/s. Preferably, the polystyrene microspheres are monodisperse polystyrene microspheres (produced by Tianjin BeisLei chromatography development center). The invention selects two polystyrene microspheres: one is polystyrene microsphere with size much smaller than the wavelength of sound wave, and the diameter is 0.24 mm; one is polystyrene microspheres of size up to the order of magnitude of the wavelength, with a diameter of 1.5 mm.

According to the invention, the operating system also comprises an electron microscope 50 for photographing and recording the process of capturing and moving the particles by the focused petal acoustic beams, and an acoustic absorber. Preferably, the electron microscope imaging system consists of a high-definition zoom lens, a microscope support, a high-definition industrial camera and related video processing software. The sound absorber is placed at the bottom of the water tank to effectively reduce the influence of reflected sound waves on a sound field. The sound absorber may be a rubber sound absorber, preferably a wedge-shaped rubber sound absorber 60, which is placed at the bottom of the water tank to more effectively reduce the influence of the reflected sound waves on the sound field. The present invention is preferably the above sound absorber, but is not limited thereto as long as the influence of the reflected sound wave on the sound field can be reduced.

The invention designs a complex sound field constructed by a manual structure flat plate, and overcomes the limitations of complex circuit regulation and control and accurate phase control of a transducer array. The artificial structural flat plate is used for generating a high-frequency sound field, and the influence of the volume size of a single transducer on the generation of the high-frequency sound field is solved. The special sound field is generated by modulating the artificial structure flat plate, so that the manipulation of a tiny object with the size far smaller than the wavelength of the sound wave is realized, and a larger object with the size reaching the magnitude order of the wavelength can be manipulated. In summary, the invention utilizes the artificial structure flat plate to modulate the sound field to form a plurality of focusing petal sound beams with special configurations, respectively captures particles with different sizes at the mechanical balance position of the petal sound beams, and freely transmits and transports the particles with corresponding sizes by moving the focusing petal sound beams.

The novel acoustic tweezers of the present invention are used as follows: s1, fixing the artificial structure flat plate 30 under the ultrasonic transducer through a clamp; s2, amplifying the sinusoidal electric signal generated by the signal generator through a power amplifier and inputting the amplified sinusoidal electric signal into an ultrasonic transducer, and radiating plane ultrasonic waves by using the ultrasonic transducer; s3, generating a focused petal sound field by the planar ultrasonic wave through the artificial structure flat plate 30; s4, capturing the polystyrene microspheres on the object stage 40 to the central area of the acoustic beam by using the acoustic radiation force characteristic of the focused petal acoustic beam; s5, moving the focused petal sound beams generated by the ultrasonic transducer and the artificial structure flat plate 30 by controlling the three-dimensional translation device 10, and transporting the polystyrene microspheres to any position on a culture dish; s6, shooting and recording the process of controlling the polystyrene microspheres by focusing the petal sound beams by using an electron microscope, and post-processing the video by using video processing software of a computer.

According to the present invention, when a plane acoustic wave is incident on the artificial structural flat plate 30, the transmission sound field depends on the distribution of the curved slits on the structural flat plate. Therefore, on the basis of ensuring the distribution characteristics of the curved slits on the structural flat plate, the artificial structural flat plate can be square or in any other shape. Preferably, the artificial structural flat plate has a cylindrical geometry with a diameter and thickness D and t, respectively.

According to the invention, the artificial structure slab is uniformly divided into m sectors, each sector being constituted by two groups of discrete curvilinear slits, respectively marked I and II. The radius of the initial curve seam of I and II is r₀And r₁The radial distance between adjacent slits is g, the width of the slits is d, and the number of the slits is L. As shown in fig. 3(a), when m is 1, the curved slits of I and II are respectively expressed as: r is_I(θ)＝r₀G, theta is more than or equal to 0 and less than or equal to pi and r_II(θ)＝r₁G, phi ≦ theta ≦ 2 pi, L ═ 1,2, …, 6. As shown in fig. 3(b), when m is 5, the curved slits of I and II are respectively expressed as: r is_I(θ)＝r₀G,. pi. (2 n-2)/5. ltoreq. theta. ltoreq.p. (2n-1)/5 and r_II(θ)＝r₁+(L-1)g，π(2n-1)/5≤θ≤π(2n)/5，L＝1,2,…,6，n＝1,2,…,5。

In the system, I and I are on the artificial structure plateInitial radius r of curve I seam₀And r₁Certain conditions are met: r is₁＝r₀+ g/2. Preferably, the geometric parameter r₀、r₁G, D, D and t may be set to 7mm, 7.85mm, 1.7mm, 0.6mm, 35mm and 3mm, respectively.

The artificial structure flat plate generates a focused petal sound beam based on the sound wave diffraction action principle, and particularly, the corresponding transmission sound field distribution can be calculated according to a Rayleigh-Sophia diffraction integral formula:

where ρ andrespectively corresponding to the polar diameter and polar angle of the observation plane of the sound field, z represents the distance from the artificial structure flat plate to the observation plane,from a source point (r, theta, z) to an observation pointDistance of (p) ()₀Density of the background medium.

Fig. 4 and 5 correspond to theoretical results of focused petal sound field intensity and phase distribution with m 1 and m 5, respectively. The working frequency of the plane incident ultrasonic wave is 1MHz, the background medium is water, and the density and the sound velocity are respectively 1000kg/m³And 1490 m/s. For a focused petal sound beam with m being 1, a zero sound intensity area appears along a central axis, the intensity distribution of a sound field is divided into a left part and a right part, and a sound intensity bright spot exists on the left side and the right side; the central axis of the phase distribution has a phase dislocation line, the phase distribution is divided into a left part and a right part, and the left side and the right side have a phase difference of pi. For a focused petal sound beam with m being 5, five zero sound intensity areas evenly divide the intensity distribution into ten parts, which causes ten sound intensity bright spots to appear in the center of the intensity distribution; meanwhile, five phase dislocation lines divide the phase distribution into ten sectors, and pi exists between adjacent sectorsThe phase difference of (1). As m increases, the petal-shaped pattern increases, which in turn causes the central zero sound intensity area of the petal sound beam to gradually increase. These characteristics are consistent with the properties of the associated petal sound beams, indicating that the artificial structural plate is designed to perfectly produce the desired focused petal sound beams.

Fig. 6(a) corresponds to a stainless steel artificial structure experimental sample producing a focused petal acoustic beam with m-1, which is prepared by laser engraving technique. The signal generator generates a continuous sinusoidal signal with the frequency of 1MHz, and the sinusoidal signal enters the ultrasonic transducer through the power amplifier to generate plane ultrasonic waves. When the plane ultrasonic wave with the frequency of 1MHz is incident to the artificial structure flat plate, the sound wave passing through the curve slit forms a focusing petal sound beam with a special configuration due to the coherent diffraction effect. Fig. 6(b) and (c) show experimental measurement results and numerical simulation results of sound field distribution of focused petal sound beam with m-1 at z-4 λ, respectively. Fig. 6(d) corresponds to a stainless steel artificial structure experimental sample producing a focused petal acoustic beam with m-5. Fig. 6(e) and (f) show experimental measurement results and numerical simulation results of sound field distribution of the focused petal sound beam with m-5 at z-4 λ, respectively. The consistency of the experimental results and the simulation results proves that the two prepared stainless steel artificial structure samples can well generate the focused petal sound beams with m being 1 and 5.

Figure 7 shows the results of the capture and movement of smaller polystyrene microspheres by focused petal acoustic beams with m-1. The signal generator generates a continuous sinusoidal signal with the frequency of 1MHz, the incident electric power of the ultrasonic transducer is about 14W through the power amplifier, the planar ultrasonic waves emitted by the ultrasonic transducer generate focused petal acoustic beams through the stainless steel artificial structure flat plate, and the polystyrene microspheres are freely controlled by utilizing the acoustic radiation force characteristic of a sound field. As shown in fig. 7(a), polystyrene microspheres of about 0.24mm (0.16 λ) in diameter were placed in close proximity to the focused petal acoustic beam at m-1. When the plane ultrasonic waves are incident to the corresponding stainless steel artificial structure flat plate, the polystyrene microspheres rapidly move to the central position of the focused petal sound beam. As shown in fig. 7(b), when the focused petal acoustic beam with m-1 moves a relatively large distance, the polystyrene microsphere moves along with the focused petal acoustic beam. The experimental results prove that the focusing petal sound beam with m-1 based on the stainless steel structural plate can flexibly capture and transport the smaller polystyrene microspheres.

Figure 8 shows the results of the manipulation of larger Mie particles by a focused petal beam with m-5. As shown in fig. 8(a), polystyrene microspheres of about 1.5mm (1 λ) in diameter were placed in close proximity to the focused petal acoustic beam at m-5. When the plane ultrasonic waves are incident to the corresponding stainless steel artificial structure flat plate, the polystyrene microspheres are quickly captured to the central position of the focused petal sound beam. As shown in fig. 8(b), when the focused petal acoustic beam with m-5 moves a relatively large distance, the polystyrene microparticles move together with the focused petal acoustic beam. The experimental results prove that the focused petal sound beam with the m-5 based on the stainless steel structural plate can capture and transport the larger polystyrene microspheres.

The foregoing is only a preferred application of the present invention, and it should be noted that, for those skilled in the art, various modifications and improvements can be made without departing from the technical principle of the present invention, and these modifications and improvements should also be considered as the protection scope of the present invention.