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(305) Production(s) de KOB W.
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Computer simulations of glasses
Auteur(s): Kob W.
(Séminaires)
Penn State (Penn State, US), 2009-04-22 |
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Computer simulations of glasses
Auteur(s): Kob W.
(Séminaires)
Lehigh (Lehigh, US), 2009-04-21 |
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When gel and glass meet: A mechanism for multistep relaxation 
Auteur(s): Chaudhuri Pinaki, Berthier L., Hurtado Pablo, Kob W.
(Article) Publié:
Physical Review E: Statistical, Nonlinear, And Soft Matter Physics, vol. 81 p.040502 (2010)
Texte intégral en Openaccess : 
PMID 20481669
Ref Arxiv: 0911.5269
DOI: 10.1103/PhysRevE.81.040502
WoS: 000277265700007
Ref. & Cit.: NASA ADS
25 Citations
Résumé: We use computer simulations to study the dynamics of a physical gel at high densities where gelation and the glass transition interfere. We report and provide detailed physical understanding of complex relaxation patterns for time correlation functions which generically decay in a three-step process. For certain combinations of parameters we find logarithmic decays of the correlators and subdiffusive particle motion.
Commentaires: 4 pages, 5 figures
Journal: Phys. Rev. E 81, 040502 (2010)
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Aging Dynamics of a Fractal Model Gel
Auteur(s): Suárez-ledo Miguel-angel, Kern N., Pitard E., Kob W.
(Article) Publié:
Chemical Physics, vol. Submitted p._ (2009)
Texte intégral en Openaccess :
Ref HAL: hal-00364561_v1
Ref Arxiv: 0812.3559
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: Using molecular dynamics computer simulations we investigate the agingdynamics of a gel. We start from a fractal structure generated by the DLCA-DEFalgorithm, onto which we then impose an interaction potential consisting of ashort-range attraction as well as a long-range repulsion. After relaxing thesystem at T=0, we let it evolve at a fixed finite temperature. Depending on thetemperature T we find different scenarios for the aging behavior. For T>0.2 thefractal structure is unstable and breaks up into small clusters which relax toequilibrium. For T<0.2 the structure is stable and the dynamics slows down withincreasing waiting time. At intermediate and low T the mean squareddisplacement scales as t^{2/3} and we discuss several mechanisms for thisanomalous time dependence. For intermediate T, the self-intermediate scatteringfunction is given by a compressed exponential at small wave-vectors and by astretched exponential at large wave-vectors. In contrast, for low T it is astretched exponential for all wave-vectors. This behavior can be traced back toa subtle interplay between elastic rearrangements, fluctuations of chain-likefilaments, and heterogeneity.
Commentaires: 30 pages, 25 figures
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Glass transitions in 1, 2, 3, and 4 dimensional binary Lennard-Jones systems
Auteur(s): Brüning Ralf, St-Onge Denis A., Patterson Steve, Kob W.
(Article) Publié:
Journal Of Physics: Condensed Matter, vol. 21 p.035117 (2009)
Texte intégral en Openaccess :
Ref HAL: hal-00365282_v1
PMID 21817275
Ref Arxiv: 0811.2995
DOI: 10.1088/0953-8984/21/3/035117
WoS: 000261833600034
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
70 Citations
Résumé: We investigate the calorimetric liquid-glass transition by performingsimulations of a binary Lennard-Jones mixture in one through four dimensions.Starting at a high temperature, the systems are cooled to T=0 and heated backto the ergodic liquid state at constant rates. Glass transitions are observedin two, three and four dimensions as a hysteresis between the cooling andheating curves. This hysteresis appears in the energy and pressure diagrams,and the scanning-rate dependence of the area and height of the hysteresis canbe described by power laws. The one dimensional system does not experience aglass transition but its specific heat curve resembles the shape of the $D\geq2$ results in the supercooled liquid regime above the glass transition. As $D$increases, the radial distribution functions reflect reduced geometricconstraints. Nearest-neighbor distances become smaller with increasing $D$ dueto interactions between nearest and next-nearest neighbors. Simulation data forthe glasses are compared with crystal and melting data obtained with aLennard-Jones system with only one type of particle and we find that withincreasing $D$ crystallization becomes increasingly more difficult.
Commentaires: 26 pages, 13 figures.
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Static and Dynamic Properties of Telechelic Gels
Auteur(s): Kob W.
Conférence invité: 7th Liquid Matter Conference (Lund, CH, 2008-06-27)
Résumé: Résumé (à complèter)
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On computer simulations of glassy materials
Auteur(s): Kob W.
Conférence invité: 10th Granada seminar on compututional and statistics physics (Granada, ES, 2008-09-14)
Résumé: Résumé (à compléter)
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