关键词: electroosmotic, micro-vortex, particle separation, Kähler manifold, tangent and cotangent bundle, fiber, Connection, tensor product, exterior product, exterior Differential, absolute differential, symplectic form, Lagrangian Form, Hamiltonian vector field, Lagrangian vector field, dynamical group, infinitesimal generator, dielectrophoretic

Abstract: A field-modulated electroosmotic flow (FMEOF) in a microchannel can be obtained by applying modulating electric fields in a direction perpendicular to the channel wall. Micro-vortexes are generated around the electrodes along with an EOF due to the surface charge on the modulated wall. When polarizable particles are suspended near the electrodes, they experience dielectrophoretic forces due to a non-uniform electric field. In this paper, micro-vortexes and dielectrophoretic forces are combined to achieve separation and trap different sized particles in a continuous flow. Numerical results indicate that by adjusting the driving electric field parallel to the channel wall and the modulating electric field, the ratio of dielectrophoretic and hydrodynamic forces can be altered. One type of particles can be trapped by micro-vortexes (negative dielectrophoresis (DEP)), and the other particles are transported to the downstream so that the particles are separated. The influence of the electrode length and the channel height on the trapping rate is investigated.

Key words: electroosmotic, particle separation, Kähler manifold, tangent and cotangent bundle, fiber, Connection, tensor product, exterior product, exterior Differential, absolute differential, symplectic form, Lagrangian Form, Hamiltonian vector field, Lagrangian vector field, dynamical group, infinitesimal generator, micro-vortex, dielectrophoretic