Well, I want the water solution in the upper layer of the model to apply a pressure gradient through the graphene oxide film in the middle,like P1 (the graphene structure wants to hold it still), I want to do a molecular dynamics simulation of a nonequilibrium state, with a vacuum layer underneath. I don't know what module to use for molecular dynamics simulation now, but I just used it Forcite NVT(P2) and NPT(P3) of the module I ran and felt that the effect was not particularly ideal.