月尘静电浮扬现象的理论模拟

对月球上的月尘静电浮扬现象进行了理论研究,对比分析了影响月球表面静电浮扬强弱的主要因素．研究过程分为两个步骤:首先采用一维PIC（particle in cell）模拟计算了月尘和月球表面的充电过程,然后基于这一结果引进试验粒子,对月尘的静电浮扬现象进行了分析研究．结果表明月尘的静电浮扬主要受两个因素的影响:太阳角和月尘颗粒的大小．月尘静电浮扬现象在日出日落时分更容易发生,即太阳角越小越容易引起剧烈的月尘浮扬现象;并且月尘粒径越小,其浮扬高度越高．     

某些幂等元半环拟簇中成员的结构

用V1,V2,V3和V4表示正规带的4个给定的拟簇.利用幂等元半环上的同余关系分别给出了.V1,.V2,.V3和.V4中成员的次直积分解和这些拟簇的M al’cev积分解,并借助Zhao X Z的"(2,2)型代数的坚固构架"理论揭示了.V1∩N.B,.V3∩中.NB成员的次直积分解与坚固构架之间的密切联系。     

Effect of Growing Size of Interaction Neighbors on the Evolution of Cooperation in Spatial Snowdrift Game

In this paper,we study the influence of the size of interaction neighbors(k) on the evolution of cooperation in the spatial snowdrift game.At first,we consider the effects of noise K and cost-to-benefit ratio r,the simulation results indicate that the evolution of cooperation depends on the combined action of noise and cost-to-benefit ratio.For a lower r,the cooperators are multitudinous and the cooperation frequency ultimately increases to 1 as the increase of noise.However,for a higher r,the defectors account for the majority of the game and dominate the game if the noise is large enough.Then we mainly investigate how k influences the evolution of cooperation by varying the noise in detail.We find that the frequency of cooperators is closely related to the size of neighborhood and cost-to-benefit ratio r.In the case of lower r,the augmentation of k plays no positive role in promoting the cooperation as compared with that of k = 4,while for higher r the cooperation is improved for a growing size of neighborhood.At last,based on the above discussions,we explore the cluster-forming mechanism among the cooperators.The current results are beneficial to further understand the evolution of cooperation in many natural,social and biological systems.