P-T phase diagram

Figure 5 P-T phase diagram of a linear PE fraction of 50,000 molecular weight. (From Ref. 85.)...

Figure 8 P-T phase diagrams of -paraffins and PE. shaded areas indicate the regions of the stable hexagonal (or rotator) phase. (From Ref. 86.)...

Figure 9 Schematic P-T phase diagrams (a) for PE including metastable and virtual phase boundaries. (From Refs. 98 and 99.) (b) For /i-paraffins including virtual boundaries.

Fig. 7-9 P-T phase diagram for bulk water. (Based on data of the Smithsonian Meteorological Tables.)...

The importance of temperature-controlled scanning calorimetry for measurements of heat capacity and of scanning transitiometry for simultaneous caloric and pVT analysis has been demonstrated for polymorphic systems [9]. This approach was used to study an enantiotropic system characterized by multiphase (and hindered) transitions, the role of heat capacity as a means to understand homogeneous nucleation, and the creation of (p, T) phase diagrams. The methodology was shown to possess distinct advantages over the more commonly used combination of characterization techniques. 

Table 2.2 clearly shows the strong differences between the two quantum liquids . It is worth noting that both isotopes have very low boiling and critical temperatures and a low density (the molar volume is more than the double than that corresponding to a classic liquid). Figure 2.4 shows the p-T phase diagrams besides the presence of a superfluid phases it is to be noted for both isotopes the missing of a triple point. 

Figure 5.12 (a) The p-T phase diagram of Si. The melting lines for the low-pressure polymorph of Si and the liquid-liquid phase transition are calculated by using the two-state model and the parameters given in Table 5.2. (b) Iso-concentration lines for species B in the p-T plane, (c)) The fraction of species B as a function of temperature at constant pressure p = 2 GPa. 

Figure 2.30. Typical one-component systems (a) Room temperature, room pressure region of the well-known PIT phase diagram of water (notice the logarithmic scale of pressure), (b) P-T phase diagram of elemental Fe. The fields of existence of the different forms of Fe are shown a (body-centred cubic Fe), (face-centred cubic), 6 (body-centred cubic, high-temperature form isostructural with a), e (hexagonal close packed), L (liquid Fe). The gas phase field, owing to the pressure scale and the not very high temperatures considered, should be represented by a very narrow region close to the T axis.

Experiments at high pressure have shown that the P-T phase diagram of butadiene is comparatively simple. The crystal phase I is separated from the liquid phase by an orientationally disordered phase II stable in a narrow range of pressure and temperature. The strucmre of phase I is not known, but the analyses of the infrared and Raman spectra have suggested a monoclinic structure with two molecules per unit cell as the most likely [428]. At room temperature, butadiene is stable in the liquid phase at pressures up to 0.7 GPa. At this pressure a reaction starts as revealed by the growth of new infrared bands (see the upper panel of Fig. 25). After several days a product is recovered, and the infrared spectrum identifies it as 4-vinylcyclohexene. No traces of the other dimers can be detected, and only traces of a polymer are present. If we increase the pressure to 1 GPa, the dimerization rate increases but the amount of polymer... 

R. Boehler, D. Errandonea, and M. Ross, The laser-heated diamond cell High P-T phase diagrams, in High Pressure Phenomena Proceedings of the International School of Physics Enrico Fermi, Course CXLVII, R. J. Hemley, G. L. Chiarotti, M. Bernasconi, and L. Ulivi, eds., lOS Press, Amsterdam, 2002, p. 55. 

AI is stable at lower temperature while A2 at higher temperature and the transition from A j to A 2 is accompanied by increase in molar volume. Both A j andA2 are denser than the liquid phase. If no metastable equilibria are observed, a P-T phase diagram for the system drawn. Each area of the P-T diagram labelled ... 

Fig. 1.1. Idealised p-T phase diagram, showing triple point O and critical point Q at temperature T., freezing temperature 7 and boiling point 7 at pressure and sublimation temperature 7 at pressure p. ...

Figure 17.3 (a) Single-component P-T phase diagram, (b) Phase diagram obtained... 

For the majority of metals the triple point lies far below atmospheric pressure and the critical point well above atmospheric pressure. The diagram given below is the P-T phase diagram of the metal M. Discuss the change of the vapour pressure when the metal is gradually heated from the solid state (a) to the temperature above the boiling point. 

Fig. 9.1. Hypothetical general p-T phase diagram for two-state cooperative protein folding, according to (9.1). The stability decreases with increasing or decreasing temperature from the AS = 0 line and with increasing or decreasing pressure from the AV = 0 line. The shape of the ellipse depends very strongly on A a and ACp...

Fig. 9.3. Temperature dependence of Snase high pressure unfolding, (a) Temperature dependence of the absolute value of the volume change of unfolding as measured by fluorescence (triangles) and FITR (squares) (b) p-T phase diagram of Snase stability by fluorescence (triangles), FITR (crosses) and SAXS (circles)...

We determined several years ago the temperature dependence of the pressure unfolding of Snase [14] using fluorescence, FTIR and SAXS to build the p-T phase diagram (Fig. 9.3). These studies showed a clear decrease in the absolute value of the volume change for unfolding as a function of temperature, although the uncertainty in the recovered values of AV did not allow us to conclude unequivocally in a linear dependence. Nonetheless, in the absence of any further information we assumed linearity and hence calculated from the slope the change in thermal expansivity between the folded and the unfolded state to be on the order of 1 ml mol-1 K-1. 

Fig. 6.6 (P,T) phase diagram of the TTF-CA system. Experimental points were obtained...

The P,T) phase diagram for the system has been prepared (Fig. 6.6) using a combination of data from neutron scattering, NQR, vibrational spectroscopy and conductivity measurements (Cailleau et al. 1997). The neutral phase is paraelectric, while the ionic phase has paraelectric and ferroelectric regions. The nature and mechanism of the phase transition has been reviewed and treated, as well as a number of other physical properties (Le Cointe et al. 1996 Cailleau et al. 1997). 

Let us first discuss the limitation of the LG phase boundary. For the bulk case this is one curve in the p, T phase diagram, describing the change of the boiling point with pressure. Such a curve starts at the triple point and runs till the critical point Its slope is determined by the heat of evaporation. In... 

Figure 6 Pressure effect on the temperature-induced and gas-assisted melting of tetracosane and PVDF (for more details and explanations, see refs. 26 and 29) (al) and (a2) heat rate evolution during fusion in the presence of supercritical CH and C 2 2 (VF), respectively (bl) fluid phase equilibria in the tetracosane/methane system and (b2) partial p—T phase diagram for the PVDF-VF and PVDF-N2 systems. Note the depression in the melting/crystallization temperatures in the pressure range up to 30 MPa for the tetracosane/CH and PVDF/VF systems...

Rios S, Quilichini M, Knorr K, Andre G (1999) Study of the (P,T) phase diagram in TID2PO4. Physica B 266 290-299... 

F, 87Rb and 119Sn NMR spectra were used to characterise the two-dimensional fluoride-ion conductor RbSn2F5 26 Proton NMR studies helped to construct the P-T phase diagram (95-300 K, 0-800, MPa) for Rb x(NH4)xI, where x = 0.29 or 0.77.27... 

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