Strengthened directivity with higher-order side lobes can be generated by the transducer with a larger radius at a higher frequency. The multi-annular pressure distributions are displayed in the cross-section of the a...Strengthened directivity with higher-order side lobes can be generated by the transducer with a larger radius at a higher frequency. The multi-annular pressure distributions are displayed in the cross-section of the acoustic vortices(AVs)which are formed by side lobes. In the near field, particles can be trapped in the valley region between the two annuli of the pressure peak, and cannot be moved to the vortex center. In this paper, a trapping method based on a sector transducer array is proposed, which is characterized by the continuously variable topological charge(CVTC). This acoustic field can not only enlarge the range of particle trapping but also improve the aggregation degree of the trapped particles. In the experiments, polyethylene particles with a diameter of 0.2 mm are trapped into the multi-annular valleys by the AV with a fixed topological charge. Nevertheless, by applying the CVTC, particles outside the radius of the AV can cross the pressure peak successfully and move to the vortex center. Theoretical studies are also verified by the experimental particles trapping using the AV with the continuous variation of three topological charges, and suggest the potential application of large-scale particle trapping in biomedical engineering.展开更多
Trapping and manipulating microscopic particles(micron or nano)in a liquid environment are of great significance for research and applications in nanoscience,engineering,and biomedicine.Although optical tweezers,magne...Trapping and manipulating microscopic particles(micron or nano)in a liquid environment are of great significance for research and applications in nanoscience,engineering,and biomedicine.Although optical tweezers,magnetic tweezers,acoustic tweezers,etc.have been successfully developed,it is still challenging to separate,select,and manipulate micron and submicron particles with comparable morphologies and sizes in trace amounts of liquids with high viscosity and extremely tiny concentrations.Herein,an electric tweezer with measurable force was introduced in an environmental transmission electron microscope(ETEM)for trapping a single submicron particle in high viscosity liquids.The critical voltages for trapping SiO_(2)and TiO_(2)spheres were determined to be 75 V and 25 V,respectively,due to their dielectric characteristics.As a result,although TiO_(2)particles exhibited a similar size and morphology,they were able to be successfully separated from a mixed suspension of SiO_(2)and TiO_(2).Moreover,by applying a reasonable bias voltage to the electric tweezer and customizing the size and shape of the tweezer tip,individual 500,750,and 1000 nm TiO_(2)spheres could be easily trapped from the corresponding TiO_(2)suspension.The displacements of atomic force microscope(AFM)cantilevers indicated that the forces to trapped a single particle gradually increased with the diameter of the particles.Additionally,the electric tweezer could precisely manipulate a single particle,and stack a specific structure on the top of the electric tweezer.When the electric tweezer was combined with an optical microscope,it could successfully transfer a 5μm SiO_(2)sphere to a HeLa cell.Precisely trapping and manipulating micron and submicron particles is the foundation for fabricating microdevices to achieve specific functions,and it also show great potential for use in biological applications.展开更多
Micro-manipulation,a cornerstone of structured light applications in biomedicine and microfluidics,necessitates beams adaptable to diverse operational demands.The double-ring Airy-Gaussian vortex beam(DRAGVB)provides ...Micro-manipulation,a cornerstone of structured light applications in biomedicine and microfluidics,necessitates beams adaptable to diverse operational demands.The double-ring Airy-Gaussian vortex beam(DRAGVB)provides an innovative solution,generating varied dynamical modes through tailored parameter selection.Notably,a continuous optical bottle structure,induced by uniform vortex interactions,facilitates the trapping and storage of multiple microparticles,with its spatial position and geometric properties adjustable via core parameter modulation to suit specific needs.Furthermore,a multi-point focusing structure,governed by the absolute difference in topological charges between inner and outer rings,enables precise microparticle capture at tunable focal plane positions,provided the charge difference exceeds one.Additionally,a distinctive structure driven by a single primary-secondary phase spiral produces photon helical convergence that spirals around the transmission axis,with its rotational direction and radius determined by the topological charge configuration,allowing for particle twisting and helical optical sieving.Micro-manipulation in the three modalities was experimentally realized,and their regulation mechanisms were deeply investigated.DRAGVB enables stronger trapping at lower powers,overcomes single-plane trapping and tunability limits of conventional structured light,and addresses the fixed-particle-count issue of annular beams,enabling flexible,controllable optical trapping and micro-manipulation.展开更多
Microflow driven by AC electrothermal pumping electrolytes with high conductivity fluid （ACET） effect is explored in order to seek new methods for （more than 0. 02 S/m） at microscale. Based on the ACET theory, a p...Microflow driven by AC electrothermal pumping electrolytes with high conductivity fluid （ACET） effect is explored in order to seek new methods for （more than 0. 02 S/m） at microscale. Based on the ACET theory, a physical model for particle trapping is established by a set of electrostatics, heat transfer and fluid dynamic equations. Further, fluid velocity fields are predicted using the software FEMLAB. Experiments are performed which verify the numerical results. The experimental results show that with appropriate electrode design, ACET effect can work on fluids with conductivity up to I. 53 S/m and trap particles at a low voltage. ACET devices can be readily integrated on chip into a microsystem. This offers insight into designing ACET lab-chips.展开更多
Geodesic acoustic modes（GAMs）are oscillating zonal mode structures unique to toroidal plasmas and are capable of regulating microscopic turbulence and associated transports.Inthispaper,three important aspects of GAM...Geodesic acoustic modes（GAMs）are oscillating zonal mode structures unique to toroidal plasmas and are capable of regulating microscopic turbulence and associated transports.Inthispaper,three important aspects of GAM dynamics are investigated,namely（1） GAM continuous spectrum and its mode conversion to kinetic GAM （KGAM）;（2） 1inear excitation of energetic particle induced GAM （EGAM） and its coupling to the GAM continuum, and （3） nonlinear saturationofEGAMviawaveparticletrapping.TheanalogybetweentheGAM展开更多
Nonlinear screening of a test charge in plasma by electrons trapped or untrapped is studied. The obtained results are in rigorous estimations mathematically in comparison with the corresponding Debye screening forms.M...Nonlinear screening of a test charge in plasma by electrons trapped or untrapped is studied. The obtained results are in rigorous estimations mathematically in comparison with the corresponding Debye screening forms.Meanwhile their validity is physically discussed and some confusions in literature are clarified.展开更多
A recent study demonstrated advancements in quantum computing by applying it to address a non-Hermitian optical manipulation problem.The emergence of exceptional points and the dynamics of optically trapped single or ...A recent study demonstrated advancements in quantum computing by applying it to address a non-Hermitian optical manipulation problem.The emergence of exceptional points and the dynamics of optically trapped single or multiple particles were simulated using a quantum computing approach.展开更多
基金Project supported by the National Key R&D Program of China(Grant No.2023YFE0201900)。
文摘Strengthened directivity with higher-order side lobes can be generated by the transducer with a larger radius at a higher frequency. The multi-annular pressure distributions are displayed in the cross-section of the acoustic vortices(AVs)which are formed by side lobes. In the near field, particles can be trapped in the valley region between the two annuli of the pressure peak, and cannot be moved to the vortex center. In this paper, a trapping method based on a sector transducer array is proposed, which is characterized by the continuously variable topological charge(CVTC). This acoustic field can not only enlarge the range of particle trapping but also improve the aggregation degree of the trapped particles. In the experiments, polyethylene particles with a diameter of 0.2 mm are trapped into the multi-annular valleys by the AV with a fixed topological charge. Nevertheless, by applying the CVTC, particles outside the radius of the AV can cross the pressure peak successfully and move to the vortex center. Theoretical studies are also verified by the experimental particles trapping using the AV with the continuous variation of three topological charges, and suggest the potential application of large-scale particle trapping in biomedical engineering.
基金financially supported by the National Natural Science Foundation of China(Nos.52372293,52471018)the S&T Program of Hebei(Nos.B2023203037,B2024203054)+1 种基金the Science Research Project of Hebei Education Department(No.JZX2024022)Central Guidance Fund for Local Science and Technology Development Project(No.246Z1101G)。
文摘Trapping and manipulating microscopic particles(micron or nano)in a liquid environment are of great significance for research and applications in nanoscience,engineering,and biomedicine.Although optical tweezers,magnetic tweezers,acoustic tweezers,etc.have been successfully developed,it is still challenging to separate,select,and manipulate micron and submicron particles with comparable morphologies and sizes in trace amounts of liquids with high viscosity and extremely tiny concentrations.Herein,an electric tweezer with measurable force was introduced in an environmental transmission electron microscope(ETEM)for trapping a single submicron particle in high viscosity liquids.The critical voltages for trapping SiO_(2)and TiO_(2)spheres were determined to be 75 V and 25 V,respectively,due to their dielectric characteristics.As a result,although TiO_(2)particles exhibited a similar size and morphology,they were able to be successfully separated from a mixed suspension of SiO_(2)and TiO_(2).Moreover,by applying a reasonable bias voltage to the electric tweezer and customizing the size and shape of the tweezer tip,individual 500,750,and 1000 nm TiO_(2)spheres could be easily trapped from the corresponding TiO_(2)suspension.The displacements of atomic force microscope(AFM)cantilevers indicated that the forces to trapped a single particle gradually increased with the diameter of the particles.Additionally,the electric tweezer could precisely manipulate a single particle,and stack a specific structure on the top of the electric tweezer.When the electric tweezer was combined with an optical microscope,it could successfully transfer a 5μm SiO_(2)sphere to a HeLa cell.Precisely trapping and manipulating micron and submicron particles is the foundation for fabricating microdevices to achieve specific functions,and it also show great potential for use in biological applications.
基金National Natural Science Foundation of China(12374281,12274311)。
文摘Micro-manipulation,a cornerstone of structured light applications in biomedicine and microfluidics,necessitates beams adaptable to diverse operational demands.The double-ring Airy-Gaussian vortex beam(DRAGVB)provides an innovative solution,generating varied dynamical modes through tailored parameter selection.Notably,a continuous optical bottle structure,induced by uniform vortex interactions,facilitates the trapping and storage of multiple microparticles,with its spatial position and geometric properties adjustable via core parameter modulation to suit specific needs.Furthermore,a multi-point focusing structure,governed by the absolute difference in topological charges between inner and outer rings,enables precise microparticle capture at tunable focal plane positions,provided the charge difference exceeds one.Additionally,a distinctive structure driven by a single primary-secondary phase spiral produces photon helical convergence that spirals around the transmission axis,with its rotational direction and radius determined by the topological charge configuration,allowing for particle twisting and helical optical sieving.Micro-manipulation in the three modalities was experimentally realized,and their regulation mechanisms were deeply investigated.DRAGVB enables stronger trapping at lower powers,overcomes single-plane trapping and tunability limits of conventional structured light,and addresses the fixed-particle-count issue of annular beams,enabling flexible,controllable optical trapping and micro-manipulation.
基金US National Science Foundation ( No ECS-0448896)Tennessee Science Alliance Award
文摘Microflow driven by AC electrothermal pumping electrolytes with high conductivity fluid （ACET） effect is explored in order to seek new methods for （more than 0. 02 S/m） at microscale. Based on the ACET theory, a physical model for particle trapping is established by a set of electrostatics, heat transfer and fluid dynamic equations. Further, fluid velocity fields are predicted using the software FEMLAB. Experiments are performed which verify the numerical results. The experimental results show that with appropriate electrode design, ACET effect can work on fluids with conductivity up to I. 53 S/m and trap particles at a low voltage. ACET devices can be readily integrated on chip into a microsystem. This offers insight into designing ACET lab-chips.
文摘Geodesic acoustic modes（GAMs）are oscillating zonal mode structures unique to toroidal plasmas and are capable of regulating microscopic turbulence and associated transports.Inthispaper,three important aspects of GAM dynamics are investigated,namely（1） GAM continuous spectrum and its mode conversion to kinetic GAM （KGAM）;（2） 1inear excitation of energetic particle induced GAM （EGAM） and its coupling to the GAM continuum, and （3） nonlinear saturationofEGAMviawaveparticletrapping.TheanalogybetweentheGAM
文摘Nonlinear screening of a test charge in plasma by electrons trapped or untrapped is studied. The obtained results are in rigorous estimations mathematically in comparison with the corresponding Debye screening forms.Meanwhile their validity is physically discussed and some confusions in literature are clarified.
文摘A recent study demonstrated advancements in quantum computing by applying it to address a non-Hermitian optical manipulation problem.The emergence of exceptional points and the dynamics of optically trapped single or multiple particles were simulated using a quantum computing approach.
