区域科学领域中的集群动力学研究综述

集群动力学及集群行为研究空间上的集群现象及其动力原理,是当前区域科学领域的研究热点和前沿视角。文章综述国外关于集群动力学及集群行为的研究起源,梳理在区域科学领域中的集群相关概念、研究历程、指标测度、形成分类与演化动力原理等相关研究,总结提炼最新研究进展和发展方向,以期对我国学者进一步研究和公共部门政策制定提供有益借鉴。

复杂动态网络传播动力学

病毒、谣言、舆论等在现实社会中各种复杂网络系统上的传播现象与人们现代社会经济生活息息相关,对复杂网络上各种传播现象的动力学行为研究是复杂网络理论的一个重要命题.从流行病学的角度,针对复杂网络传播行为中存在的动态过程,从自适应躲避、响应时滞、离散采样、开放式系统增长等方面综述了复杂网络传播动力学研究的若干进展.

基于漩涡特性的行人流自动扶梯拥堵形成分析

我国地铁客运量极大,早晚高峰期常出现短时特大客流聚集的情况。地铁建设形态特殊,大部分地铁站口采用自动扶梯进行上下客流的运输,但自动扶梯运输能力有限,其上下行口处常出现行人排队拥挤的情况,导致大量乘客聚集,极易造成安全隐患。针对该问题,文中通过分析水利工程中典型的水流漩涡特性,利用映射关系提出一种基于漩涡特性的行人流在自动扶梯前形成拥堵的分析方法;然后,利用集群动力学理论推导出行人流疏散时间模型,并采用消涡理论进行行人流拥堵消涡研究;最后,使用Matlab仿真软件对未采用消涡设计和采用消涡设计两种情况进行对比分析。结果表明,采用消涡原理设计的行人流拥堵所用疏散时间较短,能有效降低拥堵时间并减少安全隐患。

Cluster Growth Through Monomer Adsorption Processes

We propose a monomer adsorption model, in which only the monomers are allowed to diffuse and adsorb onto other clusters. By means of the generalized rate equation we investigate the kinetic behavior of the system with a special rate kernel. For the system without monomer input, the concentration aj（t） of the Aj clusters （j 〉 1） asymptotically retains a nonzero quantity, while for the system with monomer input, it decays with time and vanishes finally. We also investigate the kinetics of an interesting model with fixed-rate monomer adsorption. For the ease without monomer source, the evolution of the system will halt at a finite time; while the system evolves infinitely in time in the case with monomer source. Finally, we also suggest a connection between the fixed-rate monomer adsorption systems and growing networks.

Dynamics and Control of Infectious Diseases in Stochastic Metapopulation Models

The research on spatial epidemic models is a topic of considerable recent interest. In another hand, the advances in computer technology have stimulated the development of stochastic models. Metapopulation models are spatial designs that involve movements of individuals between distinct subpopulations. The purpose of the present work has been to develop stochastic models in order to study the transmission dynamics and control of infectious diseases in metapopulations. The authors studied Susceptible-Infected-Susceptible （SIS） and Susceptible-lnfected-Recovered （SIR） epidemic schemes, using the Gillespie algorithm, Computational numerical simulations were carried in order to explore the models. The results obtained show how the dynamics of transmission and the application of control measures within each subpopulation may affect all subpopulations of the system. They also show how the distribution of control measures among subpopulations affects the efficacy of these strategies. The dynamics of the stochastic models developed in the current study follow the trends observed in the classic deterministic designs. Also, the present models exhibit fluctuating behavior. This work highlights the importance of the spatial distribution of the population in spread and control of infectious diseases. In addition, it shows how chance could play an important role in these scenarios.

Study of Cold Fusion Reactions Using Collective Clusterization Approach

Within the framework of the dynamical cluster decay model （DCM）, the in evaporation cross-sections （σ1n） of cold fusion reactions （Pb and Bi targets） are calculated for ZCN = 104-113 superheavy nuclei. The calculations are carried out in the fixed range of excitation energy ECN = 15 ± 1 MeV, so that the comparative analysis of reaction dynamics can be worked out. First of all, the fission barriers （Bf ） and neutron separation energies （S1n） are estimated to account the decreasing cross-sections of cold fusion reactions. In addition to this, the importance of hot optimum orientations of β24-deformed nuclei over cold one is explored at fixed angular momentum and neck-length parameters. The hot optimum orientations support all the target-projectile （t,p） combinations, which are explored experimentally in the cold fusion reactions. Some new target-projectile combinations are also predicted for future exploration. Further, the In cross-sections are addressed for ZCN = 104-113 superheavy nuclei at comparable excitation energies which show the decent agrement with experimental data upto ZCN = 109 nuclei. Finally, to understand the dynamics of higher-Z superheavy nuclei, the cross-sections are also calculated at maximum available energies around the Coulomb barrier and the effect of non-sticking moment of inertia （INS） is also investigated at these energies.

Simulating ion clustering in potassium thiocyanate aqueous solutions with various ion-water models

Using a molecular dynamics simulation technique,we compared several commonly used ion-water models to describe the microscopic structures and dynamics in KSCN aqueous solutions.Results are compared with observations of femtosecond infrared vibrational-energy transfer and anisotropy measurements.The Jorgensen/TIP4P model is found to provide the best reproduction of clustering properties such as percentage of clustered ions,cluster-size distribution,concentration dependence of the water,and ion-rotation time constants.