理解随机过程分子动力学中的真实/虚拟动力学

Molecular dynamics with the stochastic process provides a convenient way to compute structural and thermodynamic properties of chemical, biological, and materials systems. It is demonstrated that the virtual dynamics case that we proposed for the Langevin equation[J. Chem. Phys. 147, 184104 (2017)] in principle exists in other types of stochastic thermostats as well. The recommended "middle" scheme[J. Chem. Phys. 147, 034109 (2017)] of the Andersen thermostat is investigated as an example. As shown by both analytic and numerical results, while the real and virtual dynamics cases approach the same plateau of the characteristic correlation time in the high collision frequency limit, the accuracy and efficiency of sampling are relatively insensitive to the value of the collision frequency in a broad range. After we compare the behaviors of the Andersen thermostat to those of Langevin dynamics, a heuristic schematic representation is proposed for understanding efficient stochastic thermostatting processes with molecular dynamics.     

甲醛和过氧化氢分子振动光谱的路径积分刘维尔动力学模拟

本文采用路径积分刘维尔动力学计算偶极矩时间导数的关联函数来得到红外光谱，通过与真实振动频率相比，发现路径积分刘维尔动力学可以比较忠实地描述振动动力学过程中的核量子效应，能够准确刻画系统温度变化和同位素取代效应引起的振动光谱变化.     

海洋减阻技术的研究现状

船舶、舰艇、鱼雷等海中航行体在海洋经济建设和海洋国防中发挥着重要作用.海中航行体的运行速度和能量消耗率是评价其性能的重要指标.利用减阻技术降低航行体在海水中的行驶阻力具有重要意义.按减阻机理对现今重要的海洋减阻技术进行分类和总结,并详细介绍其研究现状和减阻机理,主要包括仿生减阻、微气泡减阻和疏水/超疏水涂层减阻.通过对现有海洋减阻技术的总结和分析,展望了其今后的研究重点.