Magnetic levitation is a recent research hot spot; however, most of the extant configurations use two magnets with like poles facing each other. This paper proposes a novel magnetic levitation configuration that is based on a single ring magnet, and this configuration opens a wide operational space that enables object manipulation and density-based measurement. We develop a mathematical model to calculate the magnetic field around the magnet and to numerically correlate the levitation height and density of the object. Experimental results prove that this novel configuration can achieve a high accuracy (±0.0005 to ±0.0078 g/cm³) in density measurement for small-sized (∼5 μL) samples. It can manipulate particles, powders, and oil droplets effectively without any direct contact, and it has high sensitivity in the separation of multiple diamagnetic objects with slight differences in densities as well. The accuracy and sensitivity of the proposed configuration are both higher than those of the extant configurations. All of these results are expected to promote deeper study and applications of the magnetic levitation configuration in the field of density-based characterizations and manipulations.

中文翻译：

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单环磁悬浮配置，用于物体操纵和基于密度的测量

磁悬浮是最近的研究热点。但是，大多数现存配置都使用两个磁体，它们的磁极彼此面对。本文提出了一种基于单个环形磁体的新型磁悬浮配置，该配置打开了广阔的操作空间，可进行物体操纵和基于密度的测量。我们开发了一个数学模型来计算磁体周围的磁场，并在数字上关联物体的悬浮高度和密度。实验结果证明，这种新颖的配置可以实现高精度（±0.0005至±0.0078 g / cm ³）（对于小尺寸（〜5μL）样品）它可以有效地控制颗粒，粉末和油滴，而无需任何直接接触，并且它在分离多个反磁性物体（密度也有微小差异）时具有很高的灵敏度。所提出的配置的精度和灵敏度均高于现有配置的精度和灵敏度。所有这些结果有望促进基于密度的表征和操纵领域中磁悬浮结构的更深入研究和应用。