稳态条件下气溶胶粒子在口腔模型中的沉淀率

以实际人体解剖学数据为基础,利用流体力学软件构建了口腔模型。由于口腔形状不规则,流场中会有湍流产生,所以本文选用的是k-ω方程。在此基础上,假设吸入空气流量为一个常量,改变吸入气体、气溶胶粒子的物理参数,以调整St数的变化,模拟不同情况下气溶胶粒子运动情况。由模拟结果可知:气溶胶粒子在口腔中的沉淀率受粒子半径、密度、及流速的影响,并随这些量的增加而增加;沉淀率可以视作St数的函数,并随St数的增加而增加;气溶胶粒子在口腔中的沉淀分布受模型几何形状和湍流的影响,在喉部附近沉淀较为明显;粒子在口腔中将沿怎样的轨迹运动则取决于粒子在入口处的初始位置。     

Maintenance of cooperation induced by punishment in public goods games

In this paper, we study the public goods games with punishment by adopting the well-known approximate best response dynamics. It shows that the evolution of cooperation is affected by two aspects when other parameters are fixed. One is the punishment mechanism which can avoid the dilemma of lacking investment, and the other is the degree of rationality. Theoretical analysis and numerical results indicate that the existence of punishment mechanism and distribution of rationality are the keys to the enhancement of cooperation level. We also testify that they can heavily influence the payoffs of system as well. The findings in this paper may provide a deeper understanding of some social dilemmas.     

Punishment in optional public goods games

In this work,the optional public goods games with punishment are studied.By adopting the approximate best response dynamics,a micro model is given to explain the evolutionary process.Simultaneously,the magnitude of rationality is also considered.Under the condition of bounded rationality which provides a light to interpret phenomena in human society,the model leads to two types of equilibriums.One is the equilibrium without punishers and the other is the equilibrium including only punishers and cooperators.In addition,the effects of rationality on equilibriums are briefly investigated.