A-y phase transition

Fig. 11.2 Temperature dependence of the chemical isomer shift in metallic Fe. The shift is arbitrarily set at zero at 0 K. The Curie temperature and the temperature of the a-y phase transition are designated Tc and Ty and the insert shows a magnified view in the vicinity of Tc. [Ref. 1, Fig. 9]...

Var] Mossbauer spectroscopy. X-ray diffraction Kinetics of a-y phase transition, Cri2Feg4Nii4, 500, 550, 600, 650°C... 

Var] Varga, I., Kuzmann, E., Vertes, A., Kinetics of a--y Phase Transition of Fe-12Cr-4Ni Alloy Aged between 500-650°C , Hyperfine Interact., 112, 169-173 (1998) (Experimental, Phase... 

For 7=1 the Hamiltonian reduces to the Ising model and for y = 0 to the XY model. For the pure homogeneous case, /,, +i = / and = B, the system exhibits a quantum phase transition at a dimensionless coupling constant... 

Fig. 7A—C. Biochemo-mechanical function of NIPA gel with immobilized concanavalin A (A) Schematic illustration of saccharide-responsive, reversible swelling of a NIPA gel loaded with concanavalin A. Na DS"- is dextran sulfate sodium (DSS). (B) Temperature dependence for equilibrated volume of NIPA gel including the Con A-DSS complex (DSS-gel, O), MP (MP-gel, ), and free of both DSS and MP (A). The latter was prepared as a control sample as described in the text except for the use of an aqueous Con A solution instead of the Con A-DSS solution. Hysteresis was observed in the volume changes of the MP-gel and free-Con A gel on heating and cooling, indicating a discontinuous phase transition. The diameter of each gel in the collapsed state, determined at 50 °C, was d0 = 0.074 mm the volume of this gel is denoted Vp. The concentration of dry matter in the collapsed state was estimated from the preparation recipe to be 90 wt%. (C) Repeated swelling/shrinking control at 34.5 °C by alternate binding of DSS and MP to gel-entrapped Con A. (E. Kokufuta, Y.-Q. Zhang and T. Tanaka [78])...

The a - P — y phase transitions involving (Mg,Fe)2Si04 are isochemical. However, below 670 km where the Lower Mantle begins, disproportionation... 

Y. Suzuki, N. Suzuki, Y. Takasu, and I. Nishio, A study on the structure of water in an aqueous solution by solvent effect on a volume phase transition of N-isopropylacrylamide gel and low-frequency Raman spectroscopy, J. Chem. Phys. 107(15), 5890-5897 (1997). 

To demonstrate this, in Section 9.2.2 we have studied a stochastic model for an extended ZGB-model including diffusion, desorption and energetic interactions as additional steps. We have used different values of the diffusion and the desorption rates and different values for the energetic parameters. In the case of repulsive interactions the system s behaviour is strongly influenced by aa for large values of co and by ab for small values of Ico-The former parameter leads to a smooth phase transition at 1/2 and the latter to a sharp transition at y. The sharpness and the location of the phase transitions depend also on the diffusion and desorption rate of the A particles. The A-diffusion leads to an increase of the value of j/2 due to the higher reactivity of the A particles. At lower values of Ico tho system behaviour is nearly not influenced by the diffusion. The A-desorption increases the values of the critical points and smoothes the phase transition at j/2- This effect becomes very important if C is large. 

Iron behaves similarly there is a sudden increase in the uptake of hydrogen at about 900°, just the transition temperature of the a-y phase change, followed by an equally sudden release of hydrogen at about 1400°, the y-d transition temperature. Both the a and d phases are body-centred cubic. The y phase is face-centred so presumably there is greater interstitial space in that phase. 

Brace AD, Cowley RA (1980). Stractnral Phase Transitions. Taylor Francis, London Cai Y, Thorpe MF (1989) Floppy modes in network glasses. Phys Rev B 40 10535-10542 Carpenter MA, Salje EKH, Graeme-Batber A, Wrack B, Dove MT, Knight KS (1998) Cahbration of excess thermodynamic properties and elastic corrstant variatiorts dne to the a-p phase transition in quartz. Am Mineral 83 2-22... 

Liu X, Wang Y, Liebermann RC, Maniar PD, Navrotsky A. (1991) Phase transition in CaGeOs perovskite evidence from X-ray powder diffraction, thermal expansion and heat capacity. Phys Chem Minerals 18 224-230... 

On approaching the transition point of a continuous-phase transition, a critical slowing down of the fluctuations occurs (t [a(T—Tc) + Dq2] x) and the amplitudes of the fluctuations increase (< q y [a(T— Tc) + Dq2] x) at wave vector q (Fig. 7a). It can be proved that apparent pseudodivergences of the relaxation rate (]/Tr)c (T Tc) 7 (with y = 1/2 in mean field theories) can be observed near a phase transition if Tqm <3 1 where cop is the probing frequency. In that case, the associated spectral density... 

Differential scanning calorimetry (DSC) curves of levofloxacin hemihydrate measured under various conditions showed different thermograms. This behavior was attributed to the dehydration process that resulted in a multiple-phase transition. Dehydration at higher temperatures (above 70° C) gave a sharp endothermic peak in the DSC thermogram due to the melting of the y-form, and at a lower temperature (50°C) it led to the observation of a sharp endothermic peak due to the... 

The strong chemical interaction alumina-rare earth sesquioxide is considered to play a key role in the textural stabilization of the transition aluminas [142,145,170,171,184-187]. In the presence of the supported rare earth oxide, the y-AI2O3 a-AkOs phase transition, and inherently the sintering mechanism, is inhibited. 

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