POSS solid solutions exhibiting orientationally disordered phase transitions

2017 ◽  
Vol 53 (66) ◽  
pp. 9273-9276 ◽  
Author(s):  
Satoshi Morimoto ◽  
Hiroaki Imoto ◽  
Kensuke Naka
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Solid Solutions ◽  
Single Phase ◽  
Disordered Phase

A mixture of two different monofunctionalized heptaisobutyl-substituted octasilsesquioxanes formed solid solutions showing a single phase-transition temperature, which exhibited orientationally disordered (OD) phases.

scholarly journals The Effect of Selected Anions on Dipalmitoylphosphatidylcholine Phase Transitions

2002 ◽  
Vol 57 (7-8) ◽  
pp. 712-716 ◽  
Author(s):  
Adriana Przyczyna ◽  
Bożenna Różycka-Roszk ◽  
Marek Langner
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Salt Concentration ◽  
Half Width ◽  
Main Phase ◽  
Interface Properties ◽  
Transition Enthalpy ◽  
Peak Half Width

The effect of three anions, Cl-, Br- and I-, on the phase transitions of dipalmitoylphosphatidylcholine (DPPC) was measured. Main phase transition was modestly affected by these anions in the salt concentration range 0.2 M. For Cl- and Br- the temperature of main phase transition was lower (by about 0.5 °C), its half-width modestly larger and enthalpy practically unchanged, all three parameters were altered to a much larger degree. Main phase transition temperature was 1.5 °C lower and the peak half-width significantly smaller. These changes were not accompanied by any alteration in main phase transition enthalpy. Iodide shifted the pretransition temperature toward lower values and increased its half-width to such an extent that at concentrations above 100 mm it was practically undetectable. Besides cations, the presence of anions also has a distinct effect on lipid bilayer interface properties.

Ions substitution effect on the magnetic phase transition temperature of 0.5BiFeO3-0.5Pb1-xSrxTiO3 multiferroic solid solutions

2021 ◽  
Vol 576 (1) ◽  
pp. 19-28
Author(s):  
S. I. Raevskaya ◽  
S. P. Kubrin ◽  
J. Zhuang ◽  
I. P. Raevski ◽  
E. A. Bikyashev ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Solid Solutions ◽  
Magnetic Phase Transition ◽  
Magnetic Phase ◽  
Substitution Effect

scholarly journals Stabilization of model membranes during drying by compatible solutes involved in the stress tolerance of plants and microorganisms

2004 ◽  
Vol 383 (2) ◽  
pp. 277-283 ◽  
Author(s):  
Dirk K. HINCHA ◽  
Martin HAGEMANN
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Membrane Lipids ◽  
Compatible Solutes ◽  
Stress Conditions ◽  
Lipid Phase ◽  
Cellular Protection ◽  
Solute Leakage

Many organisms accumulate compatible solutes under environmental stress conditions. Cyanobacteria accumulate compatible solutes in response to increased external salinity, with tolerance increasing from Suc (sucrose) or trehalose to 2-O-(α-D-glucopyranosyl)-glycerol and glycinebetaine accumulating species. It is not clear how these different solutes influence salt tolerance. One possible explanation may be a differential ability of these solutes to stabilize membranes under stress conditions. We therefore performed drying experiments with liposomes in the presence of compatible solutes. Suc, trehalose and sorbitol protected liposomes from leakage of a soluble marker and from membrane fusion during drying and rehydration. 2-O-(α-D-glucopyranosyl)-glycerol was less effective and glycinebetaine showed hardly any effect. In combination with Suc, the latter two solutes showed improved protection. Lipid-phase transitions are known to contribute to solute leakage from liposomes. We determined phase transitions in dry membranes in the absence or presence of the solutes, using Fourier-transform infrared spectroscopy. The ability of the solutes to decrease the phase transition temperature corresponded closely to their ability to protect the liposomes against solute leakage. All solutes interacted with the phosphate in the lipid headgroups. The magnitude of the shift in the asymmetric P=O stretching vibration correlated closely with the lipid-phase transition temperature. This indicates that the degree of membrane protection afforded by the solutes is mainly determined by their ability to interact with the membrane lipids. However, this is not a determinant of cellular protection against salt stress, as the solutes show a reverse order when ranked with regard to protection against these stresses.

Phase transition metal–crown ether coordination compounds tuned by metal ions

2016 ◽  
Vol 45 (3) ◽  
pp. 1000-1006 ◽  
Author(s):  
Qiong Ye ◽  
Hui-Ting Wang ◽  
Lin Zhou ◽  
Li-Hui Kong ◽  
Heng-Yun Ye ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Transition Temperature ◽  
Transition Metal ◽  
Crown Ether ◽  
Metal Ions ◽  
Phase Transition Temperature ◽  
Coordination Compounds ◽  
Room Temperature ◽  
Metal Center

(15-Crown-5)(BiCl3) and (15-crown-5)(SbCl3) are discovered to show phase transitions above room temperature, where the phase transition temperature relates to the metal center.

Electrochemical Properties of Ag5Te2Cl0.8Br0.2, a Representative of the Solid Solutions Ag5Te2Cl1–xBrx

2008 ◽  
Vol 63 (9) ◽  
pp. 1083-1086 ◽  
Author(s):  
Melanie Bawohl ◽  
Tom Nilges
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Space ◽  
Ionic Conductivity ◽  
Phase Transition Temperature ◽  
Solid Solutions ◽  
Electronic Conductivity ◽  
Space Group ◽  
Disorder Phase Transition ◽  
Wide Range

Impedance spectroscopic investigations of Ag5Te2Cl0.8Br0.2, a selected representative of the solid solutions Ag5Te2Cl1−xBrx with x = 0 - 1, proved the mixed-conducting property of this class of materials. Two polymorphs are realized in the temperature range of 309 to 410 K, the monoclinic β - phase (space group P21/n) and the tetragonal α-phase (space group I4/mcm) with an order-disorder phase transition temperature of 336 K (DSC). A sharp increase of the total and ionic conductivity can be observed at 337 K, in good accordance with the phase transition temperature. The electronic conductivity exceeds the ionic conductivity by approximately one order of magnitude over a wide range of temperature. Conductivities are σion = 6.9×10−5 (309 K) and σtot = 4.80×10−4 Ω−1 cm−1 (310 K) for β -Ag5Te2Cl0.8Br0.2 and σion = 1.6×10−2 (395 K) and σtot = 1.73×10−1 Ω−1 cm−1 (394 K) for α-Ag5Te2Cl0.8Br0.2.

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