PREFACE 'Microtechnology' has been on a rapid technological advancement since the invention of the planar Integrated Circuit (IC) components more t h a n four decades ago. Its advancement has truly revolutionized the way we live, communicate, socialize, do business, and perform research. Imaging a world without the Internet, Email, mobile phones, and personal computers, all of which owe their existence to the commercial realization of IC technology, terms such as 'Global Village' and 'Global Economy' would still just be fanciful words. IC technology has also enabled the spawning of a new technology about two decades ago MEMS (Microelectromechanical Systems) which has already proved itself as a foundation technology, i.e., MEMS has already revolutionized the way we direct optical waves, transport biological entities, and sense physical parameters. MEMS is slowly finding its ways into the commercial world, and without a doubt, it will someday affect the way we live, communicate, and socialize just as IC has done for us. Interestingly, by merging IC and MEMS technologies, i.e., highly sophisticated control circuit systems and Silicon tips, 'Nanotechnology' has become a reality. Imaging a world without an Atomic Force Microscope, which allows us now to see the ~nano-world', then researchers would still be in the 'Dark Ages' in terms of dealing with nano entities. T h a t is, very few experimental validation would be available to complement our advanced simulation and theoretical results in predicting molecular interactions. Nanotechnology is another fundamental technology t h a t will surely revolutionize the way we live and interact. It has already created sensors t h a t performed far better than existing MEMS sensors, and it has allowed us to detect and interact with bio-molecules that were previously inaccessible by MEMS technologies. Hence, Nanotechnology can potentially provide greater revolution to h u m a n living conditions t h a n IC and MEMS combined. Through this Special Issue, the Acta Mechanica Sinica has selected a few excellent papers from the International Conference on Micro and Nano Systems (ICMNS 2002, August 11~14, 2002, Kunnfing, China) related to MEMS and Nanotechnology to highlight the most recent developments in these two exciting research disciplines. These papers will provide the readers to gain an understanding of the vast unknowns and research challenges that are faced by global engineers and scientists who are devoted in exploring the frontier of knowledge in these fields. We hope these papers will invigorate more researchers to participate in the humanity's march towards the micro and nano worlds. Best Regards,

Zhemin Zheng Chairman International Scientific Advisory Board of ICMNS 2002 April 5, 2004