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SUMMARY:Detection of First Order Liquid-Liquid Phase Transitions - Profess
 or Neville Greaves\, Aberystwyth University
DTSTART:20081024T103000Z
DTEND:20081024T113000Z
UID:TALK14031@talks.cam.ac.uk
CONTACT:Dr. Z Chen
DESCRIPTION:Combining small angle and wide angle x-ray scattering with aer
 odynamic levitation techniques has enabled in situ detection of phase tran
 sitions in the liquid state under contactless conditions1. At very high te
 mperatures yttria-alumina melts show a first order transition\, previously
  inferred from phase separation in quenched glasses.  We show how the tran
 sition coincides with a narrow and reversible maximum in SAXS indicative o
 f liquid unmixing on the nanoscale combined with an abrupt realignment in 
 WAXS features related to reversible shifts in polyhedral packing on the at
 omic scale.  We also observed a rotary action in the suspended supercooled
  drop driven by repetitive transitions – a polyamorphic rotor – from w
 hich the reversible changes in molar volume and entropy can be estimated. 
  These results have important implications for the nature of phase transit
 ions in other liquids and glasses.\n\n1 Detection of First Order Liquid-Li
 quid Phase Transitions in Yttrium Oxide – Aluminium Oxide Melts. G.N. Gr
 eaves\, M.C. Wilding\, S. Fearn\, D. Langstaff\, F. Kargl\, S. Cox\, O. Ma
 jérus\, Q. Vu Van\, C.J. Benmore\, R. Weber\, C.M. Martin\, L. Hennet\, S
 cience in press 2008. \n\n\n
LOCATION:Kapitza Building Seminar Room\, Cavendish Laboratory\, Department
  of Physics
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