Impact Of Phase Transition Research Articles

Impact of Phase Transitions on Temperature Evolution of Absorption Spectra and Electron–Phonon Interactions in [N(C2H5)4]2CoCl2Br2 Crystals

Absorption spectra and structural parameters of [N(C2H5)4]2CoCl2Br2 (TEACCB-2) crystals were investigated. Absorption bands corresponding to internal electronic transitions of Co2+ were identified. The impact of phase transitions on the temperature evolution of absorption spectra was studied. The low-energy tail of the absorption edge formed by ligand–metal charge-transfer electronic transitions was shown to be exponential and obeyed the empirical Urbach rule in the two high-temperature crystal phases. The temperatures and types of phase transitions at T1 = 244 K and T2 = 228 K (in cooling mode) were refined by analyzing the temperature changes of the main characteristics of the obtained spectra. An anomaly at T3 = 200 K was detected for the first time in TEACCB-2 bulk crystals and appeared earlier in the absorption spectrum of TEACCB-2 nanocrystals. It could be attributed to a phase transition.

TiO2/Attapulgite Nanocomposite as Photocatalyst: Impact of Phase Transition

TiO₂/Attapulgite Nanocomposite as Photocatalyst: Impact of Phase Transition

Impact of phase transition on the mouse oocyte spindle during vitrification

During vitrification, the glass-like solidification is the phase-transition process from liquid to solid. Phase transition is one of the major factors suspected to affect the physiology of the oocyte, such as the structure of the meiotic spindle. Therefore, it is very important to investigate the systematic and morphological alterations of the metaphase-II spindle and chromosome arrangement during complete course of a vitrification and warming process. B6D2F1 (C57BL/6 X DBA/2) mouse oocytes were cryopreserved by minimum volume cooling (MVC) method of vitrification in a solution with 15% ethylene glycol, 15% dimethylsulphoxide and 0.5 mol/l sucrose. To examine the spindle, oocytes were fixed before, during and after vitrification and were analysed by immunocytochemistry and confocal microscopy. It was shown that spindles in all oocytes could be maintained through the vitrification and warming process, even though they were exposed to extreme temperature and two rounds of phase transition. According to the sequential observations, chromosome alignment was maintained throughout the complete course of vitrification, warming and post-warming stage. The impact of phase transition was barely detectable when the oocyte was exposed to the vitrification and warming process. The oocyte spindle was able to recover immediately after warming.

Impact of phase transitions on P wave velocities

In regions where a high pressure phase is in equilibrium with a low pressure phase, the bulk modulus defined by the P– V relationship is greatly reduced. Here we evaluate the effect of such transitions on the P wave velocity. A model, where cation diffusion is the rate limiting factor, is used to project laboratory data to the conditions of a seismic wave propagating in the two-phase region. We demonstrate that for the minimum expected effect there is a significant reduction of the seismic velocity, as large as 10% over a narrow depth range.

Dynamical cluster properties in the quantum statistical mechanics of phase transitions

Investigates the influence of spontaneous symmetry breaking on the dynamical cluster properties of correlation functions of a quantum statistical ensemble, that is clustering with respect to time and space-time. While the impact of phase transitions on pure space-like clustering, i.e. the static results, is well known, less seems to be known about the dynamical behaviour of response functions and susceptibilities. Precise statements are made which show that, contrary to the static case, the decay properties depend sensitively on the type of Goldstone excitation.