共查询到19条相似文献,搜索用时 109 毫秒
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基于非平衡态分子动力学模拟方法,研究了自由分子区内纳米颗粒的热泳特性.理论研究表明,纳米颗粒与周围气体分子之间的非刚体碰撞效应会明显地改变其热泳特性,经典的Waldmann热泳理论并不适用,但尚未有定量的直接验证.模拟计算结果表明:对于纳米颗粒而言,当气-固相互作用势能较弱或气体温度较高时,气体分子与纳米颗粒之间的非刚体碰撞效应可以忽略,Waldmann热泳理论与分子动力学模拟结果吻合较好;当气-固相互作用势能较强或气体温度较低时,非刚体碰撞效应较为明显,Waldmann热泳理论与模拟结果存在较大误差.基于分子动力学模拟结果,对纳米颗粒的等效粒径进行了修正,并考虑了气体分子与纳米颗粒之间的非刚体碰撞效应,理论计算结果与分子动力学模拟结果吻合较好. 相似文献
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粗粒化模型通过简化原子性质以及原子间的相互作用实现生物大分子长时间尺度的分子动力学模拟. 深度学习通过模拟人类的认知过程实现海量数据的准确分类和回归过程. 本论文将这两种技术进行融合,利用基于深度学习的粗粒化分子动力学模拟技术研究分子在不同状态之间的变化过程,并提出基于TorchMD的分子动力学模拟的分析框架. 在本工作中,MFDP聚类算法被用于在三维的CV变量空间中进行聚类,并确定分子的若干主要状态,在完成聚类的同时,给出各类中的代表分子构象,并给出类之间的分子构象. 这为后续利用String算法分析分子在不同状态间的转换路径打下基础. 通过String算法,迭代搜索得到分子在不同状态之间的变化路径以及对应的势能变化曲线. 通过与已有文献的结果进行对比,验证了基于TorchMD的粗粒化分子动力学模拟的理论框架可以在相对较短的时间尺度里研究分子的变化过程. 相似文献
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提高液晶波前校正器的响应速度是增加液晶自适应光学系统校正带宽的关键, 而研究设计低旋转黏度的液晶分子是提高液晶波前校正器响应速度的根本方法. 利用原子水平上的分子动力学方法获得了目标分子的液相、向列相以及近晶相, 给出了理论计算液晶分子序参数以及旋转黏度的方法. 与此同时, 结合实验方法, 提出利用混合液晶分子动力学模拟来比较液晶分子旋转黏度的大小, 通过多次模拟、多起始点数据处理最大限度消除了因边界尺寸效应带来的数据波动, 最后给出了两种高性能液晶分子的具体比较结果. 这种分子动力学模拟方法能够探查分子结构细微差别对液晶相态以及旋转黏度的影响, 为设计低旋转黏度的液晶分子提供了理论支持, 必将为快速响应液晶材料的设计提供帮助. 相似文献
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使用分子动力学方法,研究过热水系统均质沸腾核化过程.采用Langevin 动力学方法控制体积可变系统的温度与压力,更好地模拟了沸腾实际物理过程.得到了液相系统体积连续膨胀、分子间距逐渐增大,最终稳定在汽相的现象学规律.当过热温度较高时,亚稳态液相系统可能在局部形成不同大小的近球形区域:气核,这些气核是不稳定的,处于不断演化之中.通过分析分子所受引力与斥力的共同作用,得到了气核形成与消亡以及多个气核融合的机理.比较了模拟结果与经典沸腾理论的差异,提出了气核生长是比气泡生长更为微观过程的认识.通过研究不同过热
关键词:
过热水系统
分子动力学
气核
临界过热度 相似文献
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E. V. Duda G. V. Kornich 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2017,11(4):762-766
Hyperdynamics is the method of accelerated molecular dynamics simulation based on lowering energy barriers while performing the dynamic simulation of a nano/atomic system. A system with reduced energy barriers between different states is obtained by changing the potential of interaction, namely, by constructing the so-called bias potential. An approach allowing a bias potential to be obtained is considered. To demonstrate this method, the hyperdynamics simulation of the diffusion of an atom, adsorbed on a 2D crystal surface, and a vacancy, located in its bulk, is carried out. The results are compared with relevant results obtained by molecular dynamics. It is shown that the hyperdynamics approach makes it possible to obtain statistical results, similar to those provided by molecular dynamics. This allows the accelerated simulation of atomic systems to be conducted with minor losses in the accuracy of results. 相似文献
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A new multiscale simulation method is formulated for the study of shocked materials. The method combines molecular dynamics and the Euler equations for compressible flow. Treatment of the difficult problem of the spontaneous formation of multiple shock waves due to material instabilities is enabled with this approach. The method allows the molecular dynamics simulation of the system under dynamical shock conditions for orders of magnitude longer time periods than is possible using the popular nonequilibrium molecular dynamics approach. An example calculation is given for a model potential for silicon in which a computational speedup of 10(5) is demonstrated. Results of these simulations are consistent with the recent experimental observation of an anomalously large elastic precursor on the nanosecond time scale. 相似文献
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M. Benoit S. Ispas P. Jund R. Jullien 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(4):631-636
A Car-Parrinello (CP) molecular dynamics simulation of vitreous silica, combined with classical molecular dynamics, is presented.
The equilibration of the liquid, quench and relaxation of the glass are performed classically using the van Beest, Kramer
and van Santen (BKS) potential [12] and the resulting configuration (coordinates and velocities) is used as input for the
CP simulation. A remarkable stability of the CP dynamics is observed justifying this procedure and validating the BKS potential.
Several structural and electronic properties are calculated and compared with experiments.
Received 23 March 1999 and Received in final form 15 July 1999 相似文献
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A path-integral Car-Parrinello molecular dynamics simulation of liquid water and ice is performed. It is found that the inclusion of nuclear quantum effects systematically improves the agreement of first-principles simulations of liquid water with experiment. In addition, the proton momentum distribution is computed utilizing a recently developed open path-integral molecular dynamics methodology. It is shown that these results are in good agreement with experimental data. 相似文献
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