ABSTRACT

The conventional atomic force microscope (AFM) comprises a single cantilever with piezoelectric base excitation and optical read-out. The micro-electromechanical system is raster scanned over a sample surface to generate topographic measures as well as information on selected material properties. For some large sample surfaces and biological processes, a single cantilever scan may render insufficient scan speeds. We therefore consider developing small-size AFM array technology to improve scan rates by parallel processing scanned information. As a first step we investigate the collective and interactive fluid dynamics between members in an array away from any sample surface. Our analysis is based on Stokes equation for incompressible flow and the two-dimensional boundary integral method. We first formulate the generalized equations and then focus on three- and five-beam configurations. The fluid dynamic behaviour of these small-size arrays are investigated for different gaps between members, Reynolds numbers and actuation modes. Special emphasis is laid on the effect of non-neighbouring members, which often, if not always, has been neglected in the existing literature. One of our findings reveals a Reynolds number dependent concave/convex hydrodynamic loading profile across the array that is introduced by non-neighbouring members in the array.

摘要

常规原子力显微镜（AFM）包括具有压电基激发和光学读数的单个悬臂。微机电系统在样品表面上进行光栅扫描，以生成形貌度量以及有关所选材料特性的信息。对于某些较大的样品表面和生物学过程，单悬臂扫描可能会导致扫描速度不足。因此，我们考虑开发小型AFM阵列技术，以通过并行处理扫描的信息来提高扫描速度。第一步，我们研究远离任何样品表面的阵列中成员之间的集体和交互式流体动力学。我们的分析基于不可压缩流的斯托克斯方程和二维边界积分法。我们首先公式化广义方程，然后集中讨论三束和五束配置。研究了这些小型阵列的流体动力学行为，以了解构件之间的间隙，雷诺数和致动模式之间的不同间隙。特别强调非邻居成员的影响，在现有文献中经常（甚至并非总是）忽略了非邻居成员的影响。我们的发现之一揭示了阵列中非邻居成员引入的，贯穿阵列的雷诺数依赖性凹/凸流体动力载荷曲线。在现有文献中已被忽略。我们的发现之一揭示了阵列中非邻居成员引入的，贯穿阵列的雷诺数依赖性凹/凸流体动力载荷曲线。在现有文献中已被忽略。我们的发现之一揭示了阵列中非邻居成员引入的，贯穿阵列的雷诺数依赖性凹/凸流体动力载荷曲线。