28 research outputs found
Explaining why simple liquids are quasi-universal
It has been known for a long time that many simple liquids have surprisingly
similar structure as quantified, e.g., by the radial distribution function. A
much more recent realization is that the dynamics are also very similar for a
number of systems with quite different pair potentials. Systems with such
non-trivial similarities are generally referred to as "quasi-universal". From
the fact that the exponentially repulsive pair potential has strong virial
potential-energy correlations in the low-temperature part of its thermodynamic
phase diagram, we here show that a liquid is quasi-universal if its pair
potential can be written approximately as a sum of exponential terms with
numerically large prefactors. Based on evidence from the literature we moreover
conjecture the converse, i.e., that quasi-universality only applies for systems
with this property
Silicon coordination changes from 4-fold to 6-fold on devitrification of silicon phosphate glass
Les marchés publics par l'analyse de cas : n°11 à 13
support écrit des travaux pratiques sous forme de casus et de propositions de résolutio