DYNAMIC CHARACTERISTICS OF MICROMACHINE COMPONENTS IN BIONIC LIQUID

为了研究仿生液体的动态特性，典型地研究了微悬臂梁的静态和动态行为。主要研究结果如下：(1)利用氮化硅薄膜在空气中的共振特性，提取了薄膜的杨氏模数。为了研究三维静电场中微悬臂梁的大挠度问题，基于薄膜大挠度弹性理论和静电场理论，建立了微悬臂梁大挠度的计算机分析系统。得到了多晶硅悬臂梁的杨氏模数与施加在悬臂梁和衬底之间的电压之间的关系。(3)提出了基于力平衡方法的原子力显微镜(AFM)力曲线测量系统的控制模型。在此基础上，设计了AFM Prove的PID控制系统，使其在1/100秒内接近快速测量周期。(4)利用激光激励的光杠杆测量了微悬臂梁在水中的共振特性。在水中的共振频率比在空气中低约1/10。利用串珠模型估算粘性流体的阻力，在串珠模型的基础上从理论上推导了其共振特性，并与实验结果进行了比较，吻合较好。

For investigation of dynamic characteristics in bionic liquid, static and dynamic behaviors of micro cantilever are typically studied. The main results were as follows.(1)Young's modulus of thin Si_3N_4 films are extracted from the resonance characteristics in air. The cantilevers are excited by Laser beams and the amplitudes are measured by optical methods.(2)To study large deflection of micro cantilever in 3-dimensional static electric field, computer analysis system is developed based on large deflection elastic theory in thin films and electrostatic field theory. Relations between the Young's modulus of the poly-Si cantilever and the applied voltages, which is applied between the cantilever and the substrate, are obtained.(3)Analytical model is proposed to control the force curve measurement system for AFM (Atomic Force Microscopy) proves based on the force balanced method. Based on this method, PID control system for AFM prove is designed to approach quick measurement period within 1/100 seconds.(4)Resonance characteristics in water are measured for micro cantilevers by optical lever, which is excited by Laser beam. The resonance frequency in water shows around 1/10 times lower than that of in air. Using the string of beads model for estimating the drag force by viscous fluids, the resonance characteristics are theoretically derived based on the strings of beads model and the results show good agreements with the experimental results.