A combined DFTB nanoreactor and reaction network generator approach for mechanism of hydrocarbon combustion

We explored the mechanism of ethylene combustion by combining density functional tight-binding based nanoreactor molecular dynamic method (DFTB-NMD) and a hidden Markov model (HMM) based reaction network generator approach. The...

Molecular dynamic simulation of performance of modified BAMO/AMMO copolymers and their effects on mechanical properties of energetic materials

Based on molecular dynamic method, densities, mechanical behavior and mechanical performance of P(BAMO/ AMMO) (Polymer 1) and two novel modified P(BAMO/AMMO) (Polymer 2: containing amino group, Polymer 3: containing nitro group), and their effects on mechanical properties of four energetic materials are investigated, the main results are as follow: Polymer 2 (1.235 g/cm3, 240 ± 5 K) and Polymer 3: 1.281 g/cm3, 181 ± 3 K) possess higher densities and lower glass transition temperatures than Polymer 1 (1.229 g/cm3, 247 ± 4 K). The modification makes Polymer 1 difficult to expand, improves its mechanical properties, but has few effect on its diffusion coefficient at same temperature and state. In addition, three binders are compatible with TNT, HMX and CL-20, and may react with DNTF. All polymers particularly improve rigidity of four energetic materials, and enhance their ductility except Polymer 2 on TNT. The ability of Polymer 2 and Polymer 3 improving rigidity (except Polymer 3 on HMX) and ductility of TNT and HMX is inferior to that of Polymer 1, but it is contrary for CL-20 and DNTF (except Polymer 2 on rigidity of DNTF). Moreover, Polymer 2-based interfacial crystals exhibit higher rigidity than Polymer 3-based interfacial crystals.

Structural Simulation of Mg2SiO4 under Compression

The microstructure in Mg2SiO4 glass under high compression is studied by molecular dynamic method. This work revealed the correlation between pair radial distribution functions (PRDF) of Si-Si pair and bond angle distribution (BAD) of Si-O-Si and focus on clarifying the split peak of Si-Si PRDF. Moreover, visualizing the bonds of Si-Si at different pressures show changing of Si-Si bonds with pressure. In particularly, as increasing pressure, it forms corner-sharing, edge-sharing and face-sharing bond between SiOx coordination units results in the first peak splitting of Si-Si PRDF at high pressure. The results of Si-Si’s PRDF have also been analyzed and explained in detail.

Computer Modeling of the Formation Process of Core-Shell Nanoparticles Cu@Si

The process of nanoparticle Cu@Si formation by the molecular dynamic method using MEAM-potentials was studied. Modeling the droplet behavior demonstrates that a core-shell structure with a copper core and a silicon shell can be formed if the drop is in the liquid state, until the material is finally redistributed. The parameters of thermal stability of Cu@Si composite nanoparticles of different sizes have been determined. It is concluded that as the temperature increases, the diffusion of copper atoms to the surface begins, which leads to a change in the structure and the formation of particles with a core of the Cu@Si type.