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SUMMARY:Graduate Student  Seminar - Mr Iman Mohaghegian CUED  - Mr Wojciec
 h Szlachta CUED
DTSTART:20120518T130000Z
DTEND:20120518T140000Z
UID:TALK37814@talks.cam.ac.uk
CONTACT:Ms Helen Gardner
DESCRIPTION:Iman Mohagheghian : Impact response of polymer-metal laminates
 \n____________________\nWojciech Szlachta : Gaussian approximation potenti
 al for tungsten\nwjs31@cam.ac.uk\n\nAbstract:\n\nWe construct an interatom
 ic potential for tungsten by applying Gaussian process regression to augme
 nt an underlying Finnis-Sinclair potential with the missing quantum-mechan
 ical (QM) information. The QM information is computed directly using densi
 ty functional theory (DFT)\, and the difference between the potential ener
 gy surfaces is interpolated by the Gaussian process. As a result\, we obta
 in an interatomic potential which is no longer constrained by a fixed func
 tional form\, and is therefore capable of representing the complex potenti
 al energy landscape with high accuracy.\n\nWe represent atomic environment
 s using a set of rotationally and permutationally invariant parameters\, w
 hich act as independent variables in our regression equations. Our trainin
 g data consists of the most common crystal phases over a range of volumes 
 and strains\, as well as simple lattice defects\, such as stacking faults 
 / gamma surfaces\, vacancies and surfaces.\n\nWe find that the properties 
 of our new potential are in agreement with the DFT data\, and that the for
 ce and energy errors of the underlying Finnis-Sinclair potential are signi
 ficantly reduced. Our new potential\ncan also reproduce the structure of t
 he screw dislocation correctly\, even though it was not included in our tr
 aining data set.
LOCATION:Oatley Seminar Room\, Department of Engineering
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