2 Physics in the Micro and Nano Worlds
Micro/Nano Scale Physics
Surface Force Domination
- For conventional macro manipulation, gravitational force is dominate over surface forces, i.e., we can pick and place objects as desired
- For micro/nano manipulations, surfaces forces are dominate over gravity or inertia forces, i.e., adhesion force is a problem.
In micro/nano scales:
- Electrostatic / 静电力
- Surface Tension (capillary) 表面张力（毛细管）
- van der Waals / 范德华力
Why Make Things Small?
- Higher Frequency Response
- Faster time response
- Faster diffusion times
Quiz
- Q: In the micro world, which force is more important: body force or surface force? Why? A: surface force.
- Q: Do you know which forces we should pay much more attention to in the micro world (i.e., we normally neglect these forces in the macro world)? A: - Electrostatic, Surface Tension, van der Waals
- Q: Allometric or Isometric scaling? A: In biology, allometric. In engineering, both.
- Q: Why do we want to make things small? A: - Higher Frequency Response
- Faster time response
- Faster diffusion times
Introduction
Definition: sensors
A device which provides a usable output in response to a specified measurand
- A sensor acquires a physical parameter and converts it into a signal suitable for processing (e.g.,xs optical, electrical, mechanical)
- A transducer
- Microphone, Loud Speaker, Biological Senses (e.g., touch, sight,…etc.)