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Langevin Simulation of Non-Uniform Granular Gases   总被引:1,自引:0,他引:1       下载免费PDF全文
We present and study a fractal model of a non-uniform granular system for the first time, based on which wenumerically solve the dynamics actions in the system successfully in one-dimensional case. The multi-mixture is composed of N different particles, whose granularity distribution has the fractal characteristic. The particles are subject to inelastic mutual collisions and obey to Langevin equation between collisions. Far from the equilibrium,i.e. the given typical relaxation time τ of the driving Brownian process is much larger than the mean collision time τc, the results of simulation indicate that the degree of inhomogeneity in the granularity distribution signed by the fractal dimension D of size distribution has great influence on the dynamics actions of the system. The velocity distribution deviates obviously from the Gaussian distribution and the particles cluster more pronouncedly with the larger value of D in the system. The velocity distribution and spatial clnsterization change with D are presented.  相似文献   
2.
We numerical simulate the propagation behaviour and people distribution trait of epidemic spreading in mobile individuals by using cellular automaton method. The simulation results show that there exists a critical value of infected rate fluctuating amplitude, above which the epidemic can spread in whole population. Moreover, with the value of infected rate fluctuating amplitude increasing, the spatial distribution of infected population exhibits the spontaneous formation of irregular spiral waves and convergence phenomena, at the same time, the density of different populations will oscillate automatically with time. What is more, the traits of dynamic grow clearly and stably when the time and the value of infected rate fluctuating amplitude increasing. It is also found that the maximal proportion of infected individuals is independent of the value of fluctuating amplitude rate, but increases linearly with the population density.  相似文献   
3.
We study the stochastic four-state sandpile model on the square lattice. The static and dynamical properties of the model are investigated and compared with the deterministic sandpile model of Bak, Tang, and Wiesenfeld [Phys. Rev. Lett. 59 (1987) 381]. The numerical results show that the stochastic model defines a new universality class with respect to the deterministic sandpile. We also find that the waves in an avalanche are uncorrelated in the stochastic model (in the BTW model, the waves in an avalanche are correlated). The physical origin of the critical behaviour of the stochastic model being different from that of the BTW model is ascribed to the ordering and deterministic property of the toppling law in the BTW model.  相似文献   
4.
We introduce a sandpile model driven by degree on scale-free networks, where the perturbation is triggered at nodes with the same degree. We numerically investigate the avalanche behaviour of sandpile driven by different degrees on scale-free networks. It is observed that the avalanche area has the same behaviour with avalanche size. When the sandpile is driven at nodes with the minimal degree, the avalanches of our model behave similarly to those of the original Bak-Tang-Wiesenfeld (BTW) model on scale-free networks. As the degree of driven nodes increases from the minimal value to the maximal value, the avalanche distribution gradually changes from a clean power law, then a mixture of Poissonian and power laws, finally to a Poisson-like distribution. The average avalanche area is found to increase with the degree of driven nodes so that perturbation triggered on higher-degree nodes will result in broader spreading of avalanche propagation.  相似文献   
5.
以不同方法将微分同胚约束(D约束)对扩展圈表象抽象波函数的作用特殊化到圈表象上.以Chern–Simons两点传播子乘积项为量子引力态基本片段,构造出了满足齐次D约束作用的扩展knot不变量引力态(*φG)n.对其中n=1,2之引力态分别进行了满足齐次D约束的具体证明;对n>2之引力态给出了一般证明.  相似文献   
6.
利用将代数约束展开的方法,计算了真空哈密顿约束(H0约束)对微分同胚不变的扩展knot态(φG)2,(φG)3,φGJ2的作用.结果表明,它们在H0约束下均具有非齐次性质.给出了态(φG)2非齐次性的消除方法 关键词:  相似文献   
7.
We numerically investigate the quenched random directed sandpile models which are local, conservative and Abelian. A local flow balance between the outflow of grains during a single toppling at a site and the total number of grains flowing into the same site plays an important role when all the nearest-neighbouring sites of the above-mentioned site topple for once. The quenched model has the same critical exponents with the Abelian deterministic directed sandpile model when the local flow balance exists, otherwise the critical exponents of this quenched model and the annealed Abelian random directed sandpile model are the same. These results indicate that the presence or absence of this local flow balance determines the universality class of the Abelian directed sandpile model.  相似文献   
8.
We numerically investigate the effect of four kinds of partial attacks of multiple targets on the Barabási Albert (BA) scale-free network and the Erdos-Rényi (ER) random network. Comparing with the effect of single target complete knockout we find that partial attacks of multiple targets may produce an effect higher than the complete knockout of a single target on both BA scale-free network and ER random network. We also find that the BA scale-free network seems to be more susceptible to multi-target partial attacks than the ER random network.  相似文献   
9.
给出了微分同胚群的表示.以扩展的Gauss不变量φG和Jones多项式第二个系数J2为基本片段,构造了满足齐次微分同胚约束(D约束)的扩展knot不变量引力态φGJ2,(J2)2和(φG)2J2.得到了它们的具体表式,并通过具体计算,给出了它们满足齐次D约束的证明. 关键词: 微分同胚约束 扩展knot不变量 量子引力态  相似文献   
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