Structural transitions in ice samples at low temperatures and pressures

Neutron Scattering on Impurity Nanoclusters in Gel Samples

“…On heating the icy sample to the temperature of up to 110 K (for heavy water up to 130 K), the amorphous phase was transformed to crystalline cubic phase and then we observed the transformation into the convenient hexagonal phase. As mentioned above, the sizes of initial cubic ice crystals were 6-10 nm [19]. In the case of ethanol samples, the transition from amorphous to monoclinic phase occurred at a temperature of ∼ 110 K and the sizes of crystallites were close to 30-40 nm.…”

“…We carried out a set of experiments to gain a better understanding of the properties and the behavior of IHG samples in He-II as a cold neutron moderator and UCN converter. The neutron studies are supported by X-ray investigations [19] of the structure and the phase transitions in the highly dispersed icy powder which are created following the decay of the water and ethanol gel samples on heating them above the temperature of 5 K in He gas atmosphere.…”

Investigation on methane hydrate formation in silica gel particles below the freezing point

“…59,61 So the metastable cubic ice was also formed because the reections at about 24.2 , 40.1 and 47.5 2q were also assigned to the (111), (220) and (311) crystal planes of cubic ice. [58][59][60][62][63][64] The ratio of the height of the reection peaks (Ic111) to the height of the reection peaks (Ih101) was near to 1 when there was only hexagonal ice. 9,13 Emov et al 60 had calculated that the mass percent range of cubic ice was 50-90 wt% when the ratio range of the height of the reection peaks (Ic111) to the height of the reection peaks (Ih101) was 4-6 by using the POWDER CELL program.…”

“…[58][59][60][62][63][64] The ratio of the height of the reection peaks (Ic111) to the height of the reection peaks (Ih101) was near to 1 when there was only hexagonal ice. 9,13 Emov et al 60 had calculated that the mass percent range of cubic ice was 50-90 wt% when the ratio range of the height of the reection peaks (Ic111) to the height of the reection peaks (Ih101) was 4-6 by using the POWDER CELL program. The ratio of the height of the reection peaks (Ic111) to the height of the reection peaks (Ih101) was about 9.3 in Fig.…”

“…112crystal planes of hexagonal ice, respectively. [58][59][60] We had to note that there was not only one ice structure of Ih formed on the silica gel surface but also ice of Ic. It is found from Fig.…”