The correction of buoyancy effects is tackled for particles moving close to a singular corner in creeping flow conditions.A few density-mismatched particle trajectories are used to reconstruct the dynamics of a neutra...The correction of buoyancy effects is tackled for particles moving close to a singular corner in creeping flow conditions.A few density-mismatched particle trajectories are used to reconstruct the dynamics of a neutrally-buoyant particle all over the target domain.We propose to take advantage of the dissipative dynamics of density-mismatched particles in order to probe the target domain.Thereafter,we retrieve the neutrally-buoyant particle flow all over the domain by reconstructing the phase space of the density-mismatched particulate flow and taking the limit of the particle-to-fluid density ratio tending to one.The robustness of such an approach is demonstrated by deliberately ill-conditioning the reconstruction operator.In fact,we show that our algorithm well performs even when we rely on qualitatively-different density-mismatched orbit topologies or on bundles of close trajectories rather than homogeneously distributed orbits.Potential applications to microfluidics and improvements of the proposed algorithm are finally discussed.展开更多
Since their advent in the 1980s,optical tweezers have attracted more and more attention due to their unique non-contact and non-invasion characteristics and their wide applications in physics,biology,chemistry,medical...Since their advent in the 1980s,optical tweezers have attracted more and more attention due to their unique non-contact and non-invasion characteristics and their wide applications in physics,biology,chemistry,medical science and nanoscience.In this paper,we introduce the basic principle,the history and typical applications of optical tweezers and review our recent experimental works on the development and application of optical tweezers technique.We will discuss in detail several technological issues,including high precision displacement and force measurement in single-trap and dual-trap optical tweezers,multi-trap optical tweezers with each trap independently and freely controlled by means of space light modulator,and incorporation of cylindrical vector optical beams to build diversified optical tweezers beyond the conventional Gaussian-beam optical tweezers.We will address the application of these optical tweezers techniques to study biophysical problems such as mechanical deformation of cell membrane and binding energy between plant microtubule and microtubule associated proteins.Finally we present application of the optical tweezers technique for trapping,transporting,and patterning of metallic nanoparticles,which can be harnessed to manipulate surface plasmon resonance properties of these nanoparticles.展开更多
文摘The correction of buoyancy effects is tackled for particles moving close to a singular corner in creeping flow conditions.A few density-mismatched particle trajectories are used to reconstruct the dynamics of a neutrally-buoyant particle all over the target domain.We propose to take advantage of the dissipative dynamics of density-mismatched particles in order to probe the target domain.Thereafter,we retrieve the neutrally-buoyant particle flow all over the domain by reconstructing the phase space of the density-mismatched particulate flow and taking the limit of the particle-to-fluid density ratio tending to one.The robustness of such an approach is demonstrated by deliberately ill-conditioning the reconstruction operator.In fact,we show that our algorithm well performs even when we rely on qualitatively-different density-mismatched orbit topologies or on bundles of close trajectories rather than homogeneously distributed orbits.Potential applications to microfluidics and improvements of the proposed algorithm are finally discussed.
文摘Since their advent in the 1980s,optical tweezers have attracted more and more attention due to their unique non-contact and non-invasion characteristics and their wide applications in physics,biology,chemistry,medical science and nanoscience.In this paper,we introduce the basic principle,the history and typical applications of optical tweezers and review our recent experimental works on the development and application of optical tweezers technique.We will discuss in detail several technological issues,including high precision displacement and force measurement in single-trap and dual-trap optical tweezers,multi-trap optical tweezers with each trap independently and freely controlled by means of space light modulator,and incorporation of cylindrical vector optical beams to build diversified optical tweezers beyond the conventional Gaussian-beam optical tweezers.We will address the application of these optical tweezers techniques to study biophysical problems such as mechanical deformation of cell membrane and binding energy between plant microtubule and microtubule associated proteins.Finally we present application of the optical tweezers technique for trapping,transporting,and patterning of metallic nanoparticles,which can be harnessed to manipulate surface plasmon resonance properties of these nanoparticles.