納米問題[20分]

圖片參考：http://hk.yimg.com/i/icon/16/1.gif
納米技術 .....http://hk.geocities.com/s6aa09/
科大製成世界最細單壁納米碳管
http://www.ust.hk/~webopa/news/2000_News/news1102b_C.html
納米科技的現在與將來
http://www.bhkaec.org.hk/bookman/cn1.htm
納米世界(香港)有限公司--專業保健產品
http://www.nanoworld.com.hk/tech.htm

Nanotechnology refers broadly to a field of applied science and technology whose unifying theme is the control of matter on the atomic and molecular scale, normally 1 to 100 nanometers, and the fabrication of devices with critical dimensions that lie within that size range.

It is a highly multidisciplinary field, drawing from fields such as applied physics, materials science, interface and colloid science, device physics, supramolecular chemistry (which refers to the area of chemistry that focuses on the noncovalent bonding interactions of molecules), self-replicating machines and robotics, chemical engineering, mechanical engineering, biological engineering, and electrical engineering. Much speculation exists as to what may result from these lines of research. Nanotechnology can be seen as an extension of existing sciences into the nanoscale, or as a recasting of existing sciences using a newer, more modern term.

Two main approaches are used in nanotechnology. In the "bottom-up" approach, materials and devices are built from molecular components which assemble themselves chemically by principles of molecular recognition. In the "top-down" approach, nano-objects are constructed from larger entities without atomic-level control. The impetus for nanotechnology comes from a renewed interest in Interface and Colloid Science, coupled with a new generation of analytical tools such as the atomic force microscope (AFM), and the scanning tunneling microscope (STM). Combined with refined processes such as electron beam lithography and molecular beam epitaxy, these instruments allow the deliberate manipulation of nanostructures, and led to the observation of novel phenomena.

Examples of nanotechnology in modern use are the manufacture of polymers based on molecular structure, and the design of computer chip layouts based on surface science. Despite the great promise of numerous nanotechnologies such as quantum dots and nanotubes, real commercial applications have mainly used the advantages of colloidal nanoparticles in bulk form, such as suntan lotion, cosmetics, protective coatings, drug delivery, and stain resistant clothing.

2008-02-20 21:12:30 補充：
納米碳管實現了在分子水平上操控物質，令它在高科技領域的應用眾彩紛呈。例如，納米碳管令氫能燃料電池汽車的發展變得現實。雖然氫氣成本低廉、效率極高，可是氣體液化昂貴，高壓儲存亦相當危險，給實際應用帶來很多難題。由於納米碳管的直徑與氫分子相近，越細小的碳管可以儲存越高密度的氫，可望成為氫氣的最佳儲存器。加熱時，氫氣從碳管中釋放出來，燃燒並驅動車輛。納米碳管也可以用來製作納米尺度的半導體元件和導線，大大提高電腦的集成度，製成新型的微型電腦。它亦可以作場發射元件，代替目前的材料製作超薄型顯示器，我們家中的電視機將變得更薄更清晰。