X-Message-Number: 1110 From: Ralph Merkle <> Subject: Low temperature operation of nanomachines Date: Thu, 6 Aug 1992 17:16:24 PDT Most of the proposed devices in "Nanosystems: Molecular Machinery, Manufacturing, and Computation" are intended to function at around 300 K (room temperature). The atomically precise basically mechanical devices designed to function in a vacuum would, for the most part, also function at lower temperatures. Levers, gears, bearings, rotating shafts, springs, rod logic, etc. would all function at arbitrarily low temperatures. Devices designed to operate in liquids (such as water) would presumably cease to function when the liquid froze. At low temperatures, thermal activation of chemical reactions would be less effective. This can be compensated for by using either mechanical forms of energy (pushing, pulling) to provide the activation energy required, or by using highly reactive compounds (radicals, carbenes, etc.) which have very low activation energy. Synthesis of structures in vacuum using highly reactive compounds and mechanical sources for activation energy could be done at arbitrarily low temperatures. Reactions which require thermal activation energy could not be used at lower temperatures. There seem to be no fundamental problem in designing systems that would function at low temperature. Many design techniques are temperature insensitive. In the long run, it is likely that the design costs for most feasible devices that we can envision today (including devices that operate at low temperature) will be quite low. However, it seems likely there will be a period during which some types of devices will be easier and less costly to design and build than other types of devices. It is difficult for me to tell exactly which devices will be cheap and easy to design during this interim period. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=1110