title: Theoretical analysis of specimen cooling rate during impact freezing and liquid-jet freezing of freeze-etch specimens.
abstract: We have carried out a theoretical analysis of specimen cooling rate under ideal conditions during impact freezing and liquid-jet freezing. The analysis shows that use of liquid helium instead of liquid nitrogen as cooling medium during impact freezing results in an increase in a specimen cooling rate of no more than 30-40%. We have further shown that when both impact freezing and liquid-jet freezing are conducted at liquid nitrogen temperature, the two methods give approximately the same specimen cooling rate under ideal conditions except for a thin outer layer of the specimen. In this region impact freezing yields the highest cooling rate.
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005614:Freeze Fracturing / Q000379:methods*; D008433:Mathematics; D008956:Models, Chemical