Density-Based High-Sensitivity Measurement and Separation via Axial Magnetic Levitation

The axial magnetic levitation has attracted attention due to its outstanding performance in operability and observability. However, the sensitivity via this levitation configuration is unsatisfactory, limiting its wide applications. To solve this issue, a new functional region with high sensitivity of the axial magnetic levitation has been discovered for the first time in this work, which can be used to realize both linear and nonlinear density-based analysis. When performing linear measurements, the new functional region can enable a significant improvement in the sensitivity up to more than 100-fold over the conventional functional region within the same levitation system, and it has a longer working distance. Meanwhile, both numerical and experimental studies have demonstrated that the new functional region can be well applied to high-sensitivity measurement and separation of diamagnetic beads with small changes in density. This work has greatly improved the functionality of the axial magnetic levitation and could significantly enhance its application capabilities in many fields, such as density measurement, object separation, biomedical diagnosis and quality control of manufactured objects.