78. Study by differential thermal analysis (DTA) of the various phase transitions encountered in frozen aqueous solutions

Cryobiology ◽  
1967 ◽  
Vol 3 (5) ◽  
pp. 383 ◽  
1992 ◽  
Vol 47 (11) ◽  
pp. 1127-1134 ◽  
Author(s):  
H. G. Kreul ◽  
R. Waldinger ◽  
A. Würflinger

Abstract Differential thermal analysis (DTA) and dielectric measurements have been performed on 2,2-dimethyl- 1-propanol (neopentanol) up to 200 MPa. Neopentanol exhibits at least one orientationally disordered (ODIC) phase (solid I) that transforms at lower temperatures to a non-plastic phase (solid II). There is evidence of a further ODIC phase denoted as solid I'. The pressure dependence of the phase transitions and the dielectric behaviour up to frequencies of 13 MHz are described. Activation enthalpies and volumes are derived from the dielectric relaxation time and compared with results for other alcohols


2019 ◽  
Vol 33 (28) ◽  
pp. 1950339 ◽  
Author(s):  
Y. I. Aliyev ◽  
P. R. Khalilzade ◽  
Y. G. Asadov ◽  
T. M. Ilyasli ◽  
F. M. Mammadov ◽  
...  

AgCu[Formula: see text]Fe[Formula: see text]S compounds were synthesized by partial Cu[Formula: see text][Formula: see text][Formula: see text]Fe replacement in the AgCuS crystal at a concentration range of 0[Formula: see text][Formula: see text][Formula: see text]x[Formula: see text][Formula: see text][Formula: see text]0.03. In the differential thermal analysis spectrum obtained at a temperature range of 300 K[Formula: see text][Formula: see text][Formula: see text]T[Formula: see text][Formula: see text][Formula: see text]1300 K, endoeffect corresponding to the structural phase transition in the AgCuS compound was observed at the temperature T[Formula: see text]=[Formula: see text]938 K. It has been determined that this result is also observed in the AgCu[Formula: see text]Fe[Formula: see text]S compound obtained by partial replacement of Cu atoms by Fe atoms. However, in the compound of AgCu[Formula: see text]Fe[Formula: see text]S this effect was observed at higher temperatures. The thermal capacities and enthalpies of phase transitions were calculated for the given compounds.


2008 ◽  
Vol 20 (5) ◽  
pp. 055210 ◽  
Author(s):  
Manoj K Singh ◽  
Naba K Karan ◽  
Ram S Katiyar ◽  
J F Scott ◽  
H M Jang

1981 ◽  
Vol 36 (3) ◽  
pp. 222-225 ◽  
Author(s):  
Peter Brauer

The investigation of the order-disorder transitions of the ammonium-chlorides and -bromides, in which some of the NH4+ are replaced by Cs+, Rb+ or K+, is extended to the corresponding iodides using birefringence and differential thermal analysis. As the temperature range of the martensitic transition (Pm 3 m↔Fm 3 m) is now overlapping the temperature range of the orderdisorder transitions, the former must be included in the measurements. The results allowing an overlook are discussed using the work of Garland, Lushington, and Leung [5]


2021 ◽  
Vol 63 (6) ◽  
pp. 772
Author(s):  
С.В. Барышников ◽  
А.Ю. Милинский

The results of studies of phase transitions in mixtures of C6H16NCl (DIPAC) powders with PbTiO3 by the method of differential thermal analysis (DTA) are pre-sented. The measurements were carried out in the heating and cooling mode in the tem-perature range from 300 to 440 K. It was found that electrical interactions between ferroelectric particles lead to the appearance of additional phase transitions for DIPAC in powder mixtures.


1979 ◽  
Vol 34 (7) ◽  
pp. 862-866 ◽  
Author(s):  
Peter Brauer

Phase transitions in (NH4, M)Cl with M=Tl, Rb or Cs and (ND4, Tl)Cl as well as (NH4, M)Br and (ND4, M)Br are measured using birefringence or differential thermal analysis. The phase diagrams of the mixed systems with M=Tl having decreasing lattice constant with increasing amount of Tl are similar to the well known T(P) diagrams. Therefore the diagrams of the sys­tems with M=Rb or Cs having increasing lattice constants correspond to T(P) diagrams in the range of fictitious negative pressure P. Substitution of D for H produces an effect similar to reducing the lattice constant. The extraordinary large negative isotope effect of II-III transitions and the appearance of the birefringent phase III in the chlorides are now understood.


2010 ◽  
Vol 12 (8) ◽  
pp. 1347-1351 ◽  
Author(s):  
Hui–Yuan Wang ◽  
Min Zha ◽  
Si–Jie Lü ◽  
Cheng Wang ◽  
Qi–Chuan Jiang

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