充电参数对聚丙烯蜂窝膜驻极体压电性的影响

通过接触法充电、恒压电晕充电，以及开路热刺激放电技术，对充电参数(例如充电电压，充电时间和充电温度等)对聚丙烯蜂窝膜(PP cellular)驻极体的压电性及其热稳定性的影响的研究，并从孔洞型薄膜压电体的材料结构和理论模型出发，讨论了这些参数对其影响的原因，分析了与压电活性密切相关的空间电荷的动态特性.结果表明，合理地优化充电参数，能使这类呈闭合孔洞的聚合物蜂窝膜驻极体的压电性及其稳定性得以改善，为拓宽这类新型压电功能膜应用领域，推动其产业化进程提供了一定的理论和技术依据. 关键词： 聚丙烯蜂窝膜 压电性 充电参数 电荷输运     

一种基于元胞自动机的自适应网络病毒传播模型

自适应网络是节点动力学和网络动力学相互作用和反馈的演化网络. 基于元胞自动机建立自适应网络中易感-感染-易感(susceptible-infected-susceptible)的病毒传播模型,研究节点为了规避病毒传播所采取的多种网络重连规则对病毒传播及网络统计特征的影响. 结果表明:自适应网络中的重连规则可以有效减缓病毒传播速度,降低病毒传播规模;随机重连规则使得网络统计特征趋于随机网络;基于元胞自动机建立的传播模型清晰地表达了病毒在传播过程中的双稳态现象. 关键词： 自适应网络 传播动力学 网络动力学 元胞自动机     

多速混合车辆单车道元胞自动机交通流模型的研究

在交通流NS模型的基础上，建立了多速混合车辆单车道元胞自动机交通流模型， 通过计算机数值模拟，得到了混合车辆在不同参数下交通流模型的基本图，并对混合交通的 特性进行了分析和讨论. 关键词： 元胞自动机 混合交通流模型 计算机模拟     

Advances in the Biological Application of Force-Induced Remnant Magnetization Spectroscopy

Biomolecules participate in various physiological and pathological processes through intermolecular interactions generally driven by non-covalent forces. In the present review, the force-induced remnant magnetization spectroscopy (FIRMS) is described and illustrated as a novel method to measure non-covalent forces. During the FIRMS measurement, the molecular magnetic probes are magnetized to produce an overall magnetization signal. The dissociation under the interference of external force yields a decrease in the magnetic signal, which is recorded and collected by atomic magnetometer in a spectrum to study the biological interactions. Furthermore, the recent FIRMS development with various external mechanical forces and magnetic probes is summarized.     

Traffic Modelling for Moving-Block Train Control System

This paper presents a new cellular automaton （CA） model for train control system simulation. In the proposed CA model, the driver reactions to train movements are captured by some updated rules. The space-time diagram of traffic flow and the trajectory of train movement is used to obtain insight into the characteristic behavior of railway traffic flow. A number of simulation results demonstrate that the proposed CA model can be successfully used for the simulations of railway traffic. Not only the characteristic behavior of railway traffic flow can be reproduced, but also the simulation values of the minimum time headway are close to the theoretical values.     

Modeling and Simulation for Urban Rail Traffic Problem Based on Cellular Automata

Based on the Nagel-Schreckenberg model, we propose a new cellular automata model to simulate the urban rail traffic flow under moving block system and present a new minimum instantaneous distance formula under pure moving block. We also analyze the characteristics of the urban rail traffic flow under the influence of train density, station dwell times, the length of train, and the train velocity. Train delays can be decreased effectively through flexible departure intervals according to the preceding train type before its departure. The results demonstrate that a suitable adjustment of the current train velocity based on the following train velocity can greatly shorten the minimum departure intervals and then increase the capacity of rail transit.     

气相爆轰物理的若干研究进展

爆轰现象的研究已经有一百多年的历史了,爆轰物理的研究取得了许多重要进展.本文从爆轰波的经典理论、胞格爆轰波的多波结构、气相爆轰波形成机理、气相爆轰波传播机制等方面综述了相关的若干研究进展,评述了这些进展的科学性与局限性,并探讨了将来可能的研究方向.这些研究进展主要包括:CJ(Chapman-Jouguet)理论和ZND(Zel'dovich,von Neumann,D?ring)模型、爆轰波多波结构、爆轰胞格特征、直接起爆和爆燃转爆轰过程、热点起爆机制、爆轰波稳定性、扰动爆轰波的传播等.爆轰波是以超声速传播的自持燃烧现象,涉及了激波相互作用、燃烧化学反应、湍流扩散和流动不稳定性等复杂的气动物理过程,相关研究具有重要的学科理论意义.另外,爆轰燃烧具有高效的热化学能释放特点,在先进的热力推进技术方面有着重要的应用背景,因此相关研究也具有重要的工程应用价值.      

Simulation of pedestrian evacuation based on an improved dynamic parameter model

An improved dynamic parameter model is presented based on cellular automata. The dynamic parameters, including direction parameter, empty parameter, and cognition parameter, are formulated to simplify tactically the process of making decisions for pedestrians. The improved model reflects the judgement of pedestrians on surrounding conditions and the action of choosing or decision. According to the two-dimensional cellular automaton Moore neighborhood we establish the pedestrian moving rule, and carry out corresponding simulations of pedestrian evacuation. The improved model considers the impact of pedestrian density near exits on the evacuation process. Simulated and experimental results demonstrate that the improvement makes sense due to the fact that except for the spatial distance to exits, people also choose an exit according to the pedestrian density around exits. The impact factors α, β, and γ are introduced to describe transition payoff, and their optimal values are determined through simulation. Moreover, the effects of pedestrian distribution, pedestrian density, and the width of exits on the evacuation time are discussed. The optimal exit layout, i.e., the optimal position and width, is offered. The comparison between the simulated results obtained with the improved model and that from a previous model and experiments indicates that the improved model can reproduce experimental results well. Thus, it has great significance for further study, and important instructional meaning for pedestrian evacuation so as to reduce the number of casualties.     

Analysis of Phase Transition in Traffic Flow based on a New Model of Driving Decision

Different driving decisions will cause different processes of phase transition in traffic flow.To reveal the inner mechanism, this paper built a new cellular automaton (CA) model,based on the driving decision (DD). In the DD model, a driver's decision is divided intothree stages: decision-making, action, and result. The acceleration is taken as a decisionvariable and three core factors, i.e. distance between adjacent vehicles, their own velocity,and the preceding vehicle's velocity, are considered. Simulation results show that the DDmodel can simulate the synchronized flow effectively and describe the phase transitionin traffic flow well. Further analyses illustrate that various density will cause the phasetransition and the random probability will impact the process. Compared with the traditional NaSch model, the DD model considered the preceding vehicle's velocity, the deceleration limitation, and a safe
distance, so it can depict closer to the driver preferences on pursuing safety, stability and fuel-saving and has strong theoreticalinnovation for future studies.     

Cellular Automaton Simulations for Target Waves in Excitable Media

Using the Greenberg-Hasting cellular automata model, we study the properties of target waves in excitable media under the no-flux boundary conditions. For the system has only one excited state, the computer simulation and analysis lead to the conclusions that, the number of refractory states does not influence the wave-front speed; the wave- front speed decreases as the excitation threshold increases and increases as the neighbor radius increases; the period of target waves is equal to the number of cell states; the excitation condition for target waves is that the wave-front speed must be bigger than half of the neighbor radius.