This paper,using the rule of condensation proposed by Botet and Jullien in 1985,investigates a diffusion-limited aggregation model,which shows that the fractal dimension is bigger than used by Witten-Sander model.And ...This paper,using the rule of condensation proposed by Botet and Jullien in 1985,investigates a diffusion-limited aggregation model,which shows that the fractal dimension is bigger than used by Witten-Sander model.And also,by using the statistical method to 100 clusters,calculates the growth probability of each layer of a cluster.Futhermore,a growth probability model equivalent to the statistical average state of diffusion-limited aggregation is proposed.展开更多
The K-V beam through a hackle periodic-focusing magnetic field is studied using the particle-core model. The beam halo-chaos is found, and a power function controller is proposed based on mechanism of halo formation a...The K-V beam through a hackle periodic-focusing magnetic field is studied using the particle-core model. The beam halo-chaos is found, and a power function controller is proposed based on mechanism of halo formation and strategy of controlling halo-chaos. Multiparticle simulation was performed to control the halo by using the power function control method. The results show that the halo-chaos and its regeneration can be eliminated effectively. We also find that the radial particle density evolvement is of uniformity at the beam’s centre as long as appropriate parameters are chosen.展开更多
文摘This paper,using the rule of condensation proposed by Botet and Jullien in 1985,investigates a diffusion-limited aggregation model,which shows that the fractal dimension is bigger than used by Witten-Sander model.And also,by using the statistical method to 100 clusters,calculates the growth probability of each layer of a cluster.Futhermore,a growth probability model equivalent to the statistical average state of diffusion-limited aggregation is proposed.
基金Supported by the National Natural Science Foundation of China (Grant No. 10247005)the Natural Science Foundation of the Anhui Higher Education Bureau (Grant No. KJ2007B187)the Scientific Research Foundation of China University of Mining and Technology for the Young (Grant No. OK060119).
文摘The K-V beam through a hackle periodic-focusing magnetic field is studied using the particle-core model. The beam halo-chaos is found, and a power function controller is proposed based on mechanism of halo formation and strategy of controlling halo-chaos. Multiparticle simulation was performed to control the halo by using the power function control method. The results show that the halo-chaos and its regeneration can be eliminated effectively. We also find that the radial particle density evolvement is of uniformity at the beam’s centre as long as appropriate parameters are chosen.
