磁悬浮车辆中人员紧急疏散的仿真研究

为了对研制的八达岭低速磁浮试验列车人员疏散安全性进行评估,考虑从磁浮车辆的空间布局和人员紧急疏散的特点,在现有的元胞自动机模型和行人流模型基础上,通过人员动态调整自身速度、动态修正人员行为等技术,建立了一种基于车辆环境约束以及人员行为特性的元胞自动机模型。该模型具有人员速度可变、能以自组织现象修正人员行为的特点,经过比较验证,模型的仿真过程更加接近真实情况,仿真结果与一般经验公式得到结果相吻合。以我国正在研制的八达岭低速磁浮试验列车为仿真对象,对车辆布局对其人员的安全疏散的影响进行了计算机仿真和分析,找出了影响人员疏散效率和时间的关键因素,为设计改进提供了依据。     

A vaccination game based on public health actions and personal decisions

Susceptible-infective-removed (SIR) models are commonly used for representing the spread of contagious diseases. A SIR model can be described in terms of a probabilistic cellular automaton (PCA), where each individual (corresponding to a cell of the PCA lattice) is connected to others by a random network favoring local contacts. Here, this framework is employed for investigating the consequences of applying vaccine against the propagation of a contagious infection, by considering vaccination as a game, in the sense of game theory. In this game, the players are the government and the susceptible newborns. In order to maximize their own payoffs, the government attempts to reduce the costs for combating the epidemic, and the newborns may be vaccinated only when infective individuals are found in their neighborhoods and/or the government promotes an immunization program. As a consequence of these strategies supported by cost-benefit analysis and perceived risk, numerical simulations show that the disease is not fully eliminated and the government implements quasi-periodic vaccination campaigns.     

基于CA-气团模型的市内重气扩散模拟与研究

针对市区内的固定地点出现重气泄露,并在街区内近地扩散的事实,构造了基于细胞自动机(Cellular automata)-气团模型,用以进行上述情况模拟.将气体的宏观扩散等效视为多个气团,使用细胞自动机生成气团的运动模型.将气团的特征表示为Qi(→V0i,xi,yi),参考高斯模型确定影响半径D用以区分浓度梯度扩散Sd和自由扩散Sf,并构造了边界接触条件.假设了模拟的市内环境,使用该模型在大气稳定状态下模拟氨气扩散.结果表明:气团的扩散符合实际情况,其在某区域的个数可以代表该区域重气浓度.模拟过程中也表现出了传统模型不具备的扩散特征,这些特征与重气的实际扩散过程更为相近,从而便于逃生和灾害控制.     

基于模糊规则和BFS算法的行人疏散模型研究*

为建立更加真实的行人疏散模型,基于模糊规则和广度优先搜索（BFS）算法,利用元胞自动机,提出1种优化的行人疏散模型。引入动态模糊速度规则,建立移动速度与周边环境的模糊对应关系,从而模拟行人在不同环境下的运动速度;通过设定危险度规则,使用基于双端队列的BFS算法快速计算每个格子距离安全出口的“静态危险度”,并与出口处人群密度的“动态危险度”耦合,使元胞自发地向“总危险度”更低的方向移动;结合动态速度规则建立1种基于排队理论的出口疏散机制。结果表明:所建模型能够再现行人流自组织现象,真实地反应行人不同的移动方式以及疏散的具体过程;模型考虑了出口排队疏散机制对疏散时间的影响,使疏散效率得到提高,为行人疏散模型的建立以及公共场所的设施布局等应急疏散预案提供有效参考。     

考虑从众阈值和主体特征的人群疏散元胞自动机模型*

为研究从众行为对人群疏散效率的影响,建立考虑从众阈值和主体特征的人群疏散元胞自动机模型,通过引入从众阈值反映人群中不同个体的从众选择程度,耦合每个主体不同特征属性、不同人员认知能力导致的疏散从众选择差异,利用元胞自动机模拟人群运动状态及动态演化过程,探究从众行为对人群疏散过程的作用规律。结果表明:人群疏散中选择从众行为的人员比例与整体疏散效率存在对应关系,本模型原始工况下,当人群中约60%的人员做出从众选择时,疏散效率相对最优。     

分形与元胞自动机耦合技术应用于厦门城市生态规划

利用2002、2007年的两期TM影像数据,基于分形方法研究了厦门的城市形态特征。首先,利用网格计数分维法得出,自2002年以来分形维数从1.804增至2007年的1.847。由于其分形维数1.847已经超越了城市理想形态维数(1.71±0.02)。结合城市形态发展规律,今后厦门岛的分形维数递增速率减缓后会逐渐回归到城市理想形态维数值。其次,通过集聚分形方法确定了以厦门市政府为圆心半径6 200 m的一个范围,在此范围内合理规划生态用地,不仅会取得较大生态效益,而且会缩短整个城市的分形维数值回归的过程。最后,文章利用元胞自动机的方法,在集聚区域内对厦门岛分形回归进行了模拟分析,提出应在集聚区内转化30%的建设用地为生态用地。此集聚区不仅是城市生态规划工作的重点区域,而且也是改善厦门市整体环境质量的最佳范围。     

Early life environment and developmental immunotoxicity in inflammatory dysfunction and disease

Components of the innate immune system such as macrophages and dendritic cells are instrumental in determining the fate of immune responses and are, also, among the most sensitive targets of early life environmental alterations including developmental immunotoxicity (DIT). DIT can impede innate immune cell maturation, disrupt tissue microenvironment, alter immune responses to infectious challenges, and disrupt regulatory responses. Dysregulation of inflammation, such as that observed with DIT, has been linked with an increased risk of chronic inflammatory diseases in both children and adults. In this review, we discuss the relationship between early-life risk factors for innate immune modulation and promotion of dysregulated inflammation associated with chronic inflammatory disease. The health risks from DIT-associated inflammation may extend beyond primary immune dysfunction to include an elevated risk of several later-life, inflammatory-mediated diseases that target a wide range of physiological systems and organs. For this reason, determination of innate immune status should be an integral part of drug and chemical safety evaluation.     

Sorption,cellular distribution,and cytotoxicity of imidazolium ionic liquids in mammalian cells – influence of lipophilicity

In order to assist an integrated development of ionic liquids (ILs), a study on the sorption, distribution, and cytotoxicity of a series of 1-alkyl-3-methyl imidazolium tetrafluoroborates with C6 rat glioma cells has been performed. Cellular sorption and distribution among three cellular fractions (cytosol, nuclei, and membranes) were analysed by reversed-phase HPLC (RP-HPLC). Compounds with longer 1-alkyl substituents were sorbed with higher enrichment factors and sorption coefficients per protein than those with shorter 1-alkyl chains. The 1-octyl-3-methyl imidazolium cation (C₈MIM) was enriched 17-folds whereas C₆MIM and C₄MIM were enriched by factors of 3.5 and 2.3, respectively. After fractionation of cells by centrifugation, about 8% of C₈MIM was found in the nuclear fractions. The cytotoxicity as estimated by the tetrazolium reductase assay was increasing with the lengths of the 1-alkyl chains from C₄MIM to C₁₀MIM. Consistently, cell proliferation rates were decreasing with increasing lengths of the 1-alkyl chains. The results reveal the correlations between lipophilicity, cellular sorption, and cytotoxicity.     

体育场馆内PM2.5的环境行为与急性毒理效应对运动大鼠免疫指标的影响

通过气管滴注法建立运动大鼠非暴露式损伤模型,以研究体育场馆内不同浓度PM_(2.5)污染对运动大鼠免疫指标的影响。实验选取32只雄性Wistar SPF(specific pathogen free, SPF)大鼠,随机分为运动对照组(EC)、高剂量运动组(30 mg·kg~(-1))(HPE)、中剂量运动组(15 mg·kg~(-1))(MPE)、低剂量运动组(7.5 mg·kg~(-1))(LPE),采用一次性气管滴注染毒后进行递增负荷跑台训练,通过酶联免疫法(ELISA)测定大鼠血清和肺泡灌洗液(BALF)中克拉拉细胞蛋白(CC16)、超敏C反应蛋白(hs-CRP)、大鼠单核细胞趋化蛋白-1(MCP-1)、大鼠巨噬细胞炎症蛋白1α(MIP-1α)和中性粒细胞弹性蛋白酶(NE)的表达水平。与EC相比,LPE、MPE和HPE中MCP-1、MIP-1α和hs-CRP表现出剂量相关性升高,NE和CC16则呈剂量相关性降低,差异均有统学意义。研究表明,PM_(2.5)气管滴注可以对急性运动大鼠的免疫系统功能造成一定程度的损伤。     

考虑行人跨越障碍物能力的元胞自动机模型

为深入研究不同类型的行人跨越障碍物行为,建立改进的元胞自动机模型,利用Dijkstra算法计算静态场,根据跨越障碍物能力不同将行人分为强跨越能力、弱跨越能力和无跨越能力3类,通过调查大型商场出入口相关尺寸参数和障碍物分布情况,构建商场疏散通道的疏散场景,分析可跨越障碍物的摆放方式与长度、行人密度和在障碍物可跨越条件下出口大小等因素对疏散过程的影响。研究结果表明：考虑跨越障碍物行为更符合疏散实际情况,且具有不同跨越能力的行人达到一定比例时最有利于疏散;行人密度越小,可跨越障碍物的位置对疏散影响越明显;出口在一定大小时就已经满足疏散要求,增大出口对疏散促进作用较小。