Journal ArticleDOI
Glass Formation and Polyamorphism in Rare‐Earth Oxide–Aluminum Oxide Compositions
TLDR
In this article, the formation of single and two-phase glasses from rare-earth oxide-alumina materials was reported, which were attributed to nucleation and growth of the second liquid at a temperature below the equilibrium liquid-liquid transition temperature.Abstract:
We report formation of single- and two-phase glasses from rare-earth oxide–alumina materials. Liquids with the Y3Al5O12 and Er3Al5O12 compositions underwent a liquid–liquid phase transition which resulted in glasses with a cloudy appearance due to spheroids of one glass in a matrix of a second glass. The two glasses were isocompositional within the limits of experimental error. Clear, brilliant, single-phase glasses were obtained from La3Al5O12, ErLaYAl5O12, and compositions containing ≥5 mol% La2O3 substituted for the other rare-earth oxides. Formation of two glasses is attributed to nucleation and growth of the second liquid at a temperature below the equilibrium liquid–liquid transition temperature. Addition of lanthanum depresses the phase transition temperature below the glass transition temperature and the liquid–liquid phase transition is not observed. The results are discussed in the context of first-order liquid–liquid phase transitions (polyamorphism) and formation of single-phase glass from liquids that contain a high proportion of 4-coordinate aluminum ions.read more
Citations
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Self-assembly of amphiphilic dendritic dipeptides into helical pores
Virgil Percec,Andrés E. Dulcey,Venkatachalapathy S. K. Balagurusamy,Yoshiko Miura,Jan Smidrkal,Mihai Peterca,Sami Nummelin,Ulrica Edlund,Steven D. Hudson,Paul A. Heiney,H. Duan,Sergei Magonov,Sergei A. Vinogradov +12 more
TL;DR: A library of amphiphilic dendritic dipeptides that self-assemble in solution and in bulk through a complex recognition process into helical pores is described, finding that the molecular recognition and self-assembly process is sufficiently robust to tolerate a range of modifications to the amphiphile structure.
Journal ArticleDOI
Bulk glasses and ultrahard nanoceramics based on alumina and rare-earth oxides
TL;DR: This method avoids the impracticably high applied pressures that have been required in most cases to prepare nanocrystalline ceramics by sintering, owing to the concurrent nature of densification and grain growth under pressureless conditions.
Journal ArticleDOI
Amorphous ices: experiments and numerical simulations
TL;DR: In this paper, the authors review the recent studies concerning VHDA and its nature, and discuss the main open questions relating to the phase diagram of glassy water, which is necessary if one also wants to understand the anomalous behaviour of supercooled liquid water.
Journal ArticleDOI
Detection of First-Order Liquid/Liquid Phase Transitions in Yttrium Oxide-Aluminum Oxide Melts
G. N. Greaves,Martin Wilding,S. Fearn,D. P. Langstaff,Florian Kargl,Simon Cox,Q. Vu Van,Odile Majérus,Chris J. Benmore,Richard Weber,Christopher M. Martin,Louis Hennet +11 more
TL;DR: At very high temperatures, yttria-alumina melts show a first-order transition, previously inferred from phase separation in quenched glasses, which is shown how the transition coincides with a narrow and reversible maximum in SAXS indicative of liquid unmixing on the nanoscale, combined with an abrupt realignment in WAXS features related to reversible shifts in polyhedral packing on the atomic scale.
References
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Journal ArticleDOI
Formation of glasses from liquids and biopolymers.
TL;DR: The onset of a sharp change in ddT( is the Debye-Waller factor and T is temperature) in proteins, which is controversially indentified with the glass transition in liquids, is shown to be general for glass formers and observable in computer simulations of strong and fragile ionic liquids, where it proves to be close to the experimental glass transition temperature.
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The Nature of the Glassy State and the Behavior of Liquids at Low Temperatures.
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Phase behaviour of metastable water
TL;DR: In this article, the authors present a comprehensive series of molecular dynamics simulations which suggest that the supercooling anomalies are caused by a newly identified critical point above which the two metastable amorphous phases of ice (previously shown to be separated by a line of first-order transitions) become indistinguishable.