▎ 摘　　要

NOVELTY - The apparatus has a first coil which provides a direct current (DC) magnetic field. A second coil provides an alternating current (AC) magnetic field. A conductive substantially two-dimensional lattice structure proximates the first coil and the second coil and being biased with a voltage. The first coil, and second coil, and the conductive substantially two-dimensional lattice structure are separated by dielectric layers. A first set of contacts are disposed in contact with the conductive substantially two-dimensional lattice structure. USE - Graphene-based magnetic hall sensor apparatus for fluid flow analysis at nanoscale level. ADVANTAGE - Improves detectability of a magnetic nanoparticle using the sensor, since a small AC magnetic field of a millitesla operating at a frequency of hundreds of Hertz is used to induce an in-phase AC magnetization in the nanoparticle. Obtains two-dimensional flow velocity field of the surrounding fluid using only the magnetic character of the tracers by allying the two-dimensional positional information with the cross-correlation of the time-shifted signals received from different positions along the channel. DESCRIPTION OF DRAWING(S) - The drawing shows the schematic diagram of the determination of two-dimensional flow fields using multiple sensors. Sensor (100) Dimensional lattice structure (130) Nanoparticle (250) Channel (410)