We investigate the Hugoniot curve, shock-particle velocity relations, and Chapman-Jouguet conditions of the hot dense system through molecular dynamics （MD） simulations. The detailed pathways from crystal nitrometha...We investigate the Hugoniot curve, shock-particle velocity relations, and Chapman-Jouguet conditions of the hot dense system through molecular dynamics （MD） simulations. The detailed pathways from crystal nitromethane to reacted state by shock compression are simulated. The phase transition of N2 and CO mixture is found at about 10 GPa, and the main reason is that the dissociation of the C-O bond and the formation of C-C bond start at 10.0-11.0 GPa. The unreacted state simulations of nitromethane are consistent with shock Hugoniot data. The complete pathway from unreacted to reacted state is discussed. Through chemical species analysis, we find that the C-N bond breaking is the main event of the shock-induced nitromethane decomposition.展开更多
Understanding of metal oxidation is very critical to corrosion control,catalysis synthesis,and advanced materials engineering.Metal oxidation is a very complex phenomenon,with many different processes which are couple...Understanding of metal oxidation is very critical to corrosion control,catalysis synthesis,and advanced materials engineering.Metal oxidation is a very complex phenomenon,with many different processes which are coupled and involved from the onset of reaction.In this work,the initial stage of oxidation on titanium surface was investigated in atomic scale by molecular dynamics(MD)simulations using a reactive force field(ReaxFF).We show that oxygen transport is the dominant process during the initial oxidation.Our simulation also demonstrate that a compressive stress was generated in the oxide layer which blocked the oxygen transport perpendicular to the Titanium(0001)surface and further prevented oxidation in the deeper layers.The mechanism of initial oxidation observed in this work can be also applicable to other self-limiting oxidation.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11374217)the Shandong Provincial Natural Science Foundation,China(Grant No.ZR2014BQ008)
文摘We investigate the Hugoniot curve, shock-particle velocity relations, and Chapman-Jouguet conditions of the hot dense system through molecular dynamics （MD） simulations. The detailed pathways from crystal nitromethane to reacted state by shock compression are simulated. The phase transition of N2 and CO mixture is found at about 10 GPa, and the main reason is that the dissociation of the C-O bond and the formation of C-C bond start at 10.0-11.0 GPa. The unreacted state simulations of nitromethane are consistent with shock Hugoniot data. The complete pathway from unreacted to reacted state is discussed. Through chemical species analysis, we find that the C-N bond breaking is the main event of the shock-induced nitromethane decomposition.
基金Support of this work from the National Natural Science Foundation of China(Grant No.51361009)Work at Ames Laboratory was supported by the US Department of Energy,Basic Energy Sciences,Division of Materials Science and Engineering under Contract No.DE-AC02-07CH11358,including a grant of computer time at the National Energy Research Scientific Computing Centre(NERSC)in Berkeley,CA.
文摘Understanding of metal oxidation is very critical to corrosion control,catalysis synthesis,and advanced materials engineering.Metal oxidation is a very complex phenomenon,with many different processes which are coupled and involved from the onset of reaction.In this work,the initial stage of oxidation on titanium surface was investigated in atomic scale by molecular dynamics(MD)simulations using a reactive force field(ReaxFF).We show that oxygen transport is the dominant process during the initial oxidation.Our simulation also demonstrate that a compressive stress was generated in the oxide layer which blocked the oxygen transport perpendicular to the Titanium(0001)surface and further prevented oxidation in the deeper layers.The mechanism of initial oxidation observed in this work can be also applicable to other self-limiting oxidation.
