Density functional theory investigation of 14 N nuclear quadrupole coupling constants (NQCC) for HMX polymorphs was performed. During the calculation of NQCC and asymmetry parameter (η) of β-HMX, single molecule model is found to be worse than cluster model. The calculated results are more sensitive to the proper model than to the basis set. The calculation for β-HMX using cluster model at B3LYP/6-311＋＋G(d,p) level gives better agreement with experiment. This approach was subsequently applied to α, γ, and δ-HMXs. The difference of simulated 14 N NQR frequency was found. The NQR spectrum is useful for the study of explosive or propellant on their detection, phase transition, and aging process.

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We present a real-time wall-fountain simulation method based on the Smoothed Particle Hydrodynamics (SPH) framework. In our method, we use single layer particles projecting idea to deal with the characteristics of wallfountains such as "cling to the wall" and "sheet flow". For single layer particles, we derive the smoothing kernel functions in two-dimensional case. During the process of solving the particle density, the normalized density summation approach is used to improve the accuracy and incompressibility. To achieve more realistic motion, we also propose a wall-fluid interaction model. The achieved results show that our method can generate physically realistic wall-fountain animation in real-time on common PCs.