Выходит 4 номеров в год
ISSN Печать: 2169-2785
ISSN Онлайн: 2167-857X
Indexed in
PHASE STABILITY OF LOW-TEMPERATURE AMORPHOUS CONDENSATES OF WATER AND WATER–GAS MIXTURES
Краткое описание
The thermal regime of the growth of crystalline nuclei in amorphous layers has been investigated. There is the possibility of growth of two types of crystallization centers: cold, growing at a temperature of the amorphous phase, and hot, whose temperature is much higher than the temperature of the amorphous phase. Estimation of the conditions of appearance and growth of hot crystallization centers in amorphous layers of water has been made. Experiments on layers of amorphous ice prepared by low-temperature condensation of molecular beams with crystallization centers artificially introduced into the condensates showed the instability of a nonequilibrium system with respect to a local thermal action. The presence of water crystalline clusters in nonequilibrium layers ensured conditions for the initiation of hot centers and a transition to an explosive regime of crystallization in an amorphous medium. No fewer than three exothermal signals on the differential thermal analysis thermograms were observed that point out the development of crystallization from different "hot" centers and the random character of their distribution in the body of an amorphous sample. The crystallization of layers of amorphous ice saturated with methane in conditions of deep metastability resulted in the formation of crystal hydrates. At atmospheric pressure in a liquid n-pentane medium the retention of the gas hydrate was observed up to temperatures close to 273 K.