Adaptive resolution molecular dynamics simulation through coupling to an   internal particle reservoir
  For simulation studies of (macro) molecular liquids it would be of significant interest to be able to adjust or increase the level of resolution within one region of space, while allowing for the free exchange of molecules between open regions of different resolution or representation. We generalize the adaptive resolution idea and suggest an interpretation in terms of an effective generalized grand canonical approach. The method is applied to liquid water at ambient conditions. 
Sebastian Fritsch, Simon Poblete, Christoph Junghans, Giovanni   Ciccotti, Luigi Delle Site, and Kurt Kremer
physics.comp-ph cond-mat.soft