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Effects on Rapid Cooling of Small Samples in Quenching a
Author(s) -
CAO QIAN,
HUA TSECHAO
Publication year - 1998
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1998.tb10160.x
Subject(s) - quenching (fluorescence) , radiochemistry , chemistry , physics , optics , fluorescence
Rapid cooling of small samples is necessary both to cryofixation for electron microscopy and to vitrification for cryopreservation. Several effects on the cooling rates of small samples quenched into liquid nitrogen were studied, including the diameter of samples, the subcooling of liquid nitrogen, the quenching speed, and the quenching distance. The heat flux is up to 1.4 × 10 6 W/m 2 ; the cooling rate is also up to 8200 K/s at the CHF point of boiling curves for sphere of diameter 0.287 mm quenching into subcooled liquid nitrogen. It is also found that if the time of sample moving inside the liquid nitrogen is not longer than the time required for forming stable vapor in the liquid, the quenching boiling heat transfer is not influenced by the quenching speed. Several equations for calculating heat flux of samples are also presented.