基于元胞自动机数学模型的瓦斯抽采管道漏点定位研究

为了解决普通数学模型难以准确描述瓦斯抽采管道内流体的流动状态问题，提出了以元胞自动机模型为基础的瓦斯抽采管道漏点定位模型。根据元胞自动机在空间和时间上离散化的特性来演化管道流体在时空上的连续变化，将管径变化、管壁粗糙度、管构异件种类和数量以及温度等参数沿管道进行离散化，利用元胞自动机理论以及管道两端的信号对管道沿线压力和流量等参数变化进行预测，以判断泄漏的发生和漏点定位。通过实验验证，该方法能提高漏点定位精度。     

Kinetic assessment of persistent halogenated xenobiotics in cell culture models: comparison of mono- and poly-halogenated compounds

We evaluated the suitability of single and multiple cell type cultures as model systems to characterise cellular kinetics of highly lipophilic compounds with potential ecotoxicological impact. Confluent mono-layers of human skin fibroblasts, rat astrocytoma C6 cells, non-differentiated and differentiated mouse 3T3 cells were kept in culture medium supplemented with 10% foetal calf serum. For competitive uptake experiments up to four different cell types, grown on glass sectors, were exposed for 3 h to ¹⁴C-labelled model compounds, dissolved either in organic solvents or incorporated into unilamellar lecithin liposomes. Bromo-, or chloro-benzenes, decabromodiphenylether (DBP), and dichlorodiphenyl ethylene (DDE) were tested in rather high concentration of 20 μM. Cellular toxicity was low. Compound levels were related to protein, DNA, and triglyceride contents. Cellular uptake was fast and dependent on physico-chemical properties of the compounds (lipophilicity, molecular size), formulation, and cell type. Mono-halogenated benzenes showed low and similar uptake levels (= low accumulation compounds). DBP and DDE showed much higher cellular accumulations (= high accumulation compounds) except for DBP in 3T3 cells. Uptake from liposomal formulations was mostly higher than if compounds were dissolved in organic solvents. The extent of uptake correlated with the cellular content of triglycerides, except for DBP. Uptake competition between different cell types was studied in a sectorial multi-cell culture model. For low accumulation compounds negligible differences were found among C6 cells and fibroblasts. Uptake of DDE was slightly and that of DBP highly increased in fibroblasts. Well-defined cell culture systems, especially the sectorial model, are appropriate to screen for bioaccumulation and cytotoxicity of (unknown) chemical entities in vitro.     

Towards automatic and robust adjustment of human behavioral parameters in a pedestrian stream model to measured data

People die or get injured at mass events when the crowd gets out of control. Urbanization and the increasing popularity of mass events, from soccer games to religious celebrations, enforce this trend. Thus, there is a strong need to better control crowd behavior. Here, simulation of pedestrian streams can be very helpful: Simulations allow a user to run through a number of scenarios in a critical situation and thereby to investigate adequate measures to improve security. In order to make realistic, reliable predictions, a model must be able to reproduce the data known from experiments quantitatively. Therefore, automatic and fast calibration methods are needed that can easily adapt model parameters to different scenarios. Also, the model must be robust. Small changes or measurement errors in the crucial input parameters must not lead to disproportionally large changes in the simulation outcome and thus potentially useless results. In this paper we present two methods to automatically calibrate pedestrian simulations to the socio-cultural parameters captured through measured fundamental diagrams. We then introduce a concept of robustness to compare the two methods. In particular, we propose a quantitative estimation of parameter quality and a method of parameter selection based on a criterion for robustness. We discuss the results of our test scenarios and, based on our experience, propose further steps.     

环鄱阳湖区分区土地利用景观格局变化模拟研究

依据水环境约束力的大小,将环鄱阳湖区划分为核心、边缘和外围3个影响区。以该地区2005~2010年间土地利用情况为基准,通过构建CA-Markov-Logistic模型模拟2015年该地区土地利用格局情景,并采用景观格局指数进一步分析3个影响区土地利用景观格局变化趋势。研究表明:(1)从土地利用类型变化来看,覆盖环鄱阳湖区约82%土地面积的耕地和林地将有较大幅度的减少,而城建用地所占比重将大幅上升,对环鄱阳湖区的开发在逐渐加快;(2)从土地利用影响力来看,地类分布概率与人口城市化率、生活城市化率以及经济城市化率的空间分布有着一定的相关关系;(3)从模拟结果来看,环鄱阳湖区核心区耕地范围将缩小而水体范围将扩大,边缘区其他建设用地和农村居民点面积增加,外围区水体范围将大幅缩减,土地景观破碎化程度依次从边缘区-外围区-核心区的顺序下降,表明对鄱阳湖保护的作用正在显现,整个土地利用景观格局取向更为合理。     

白腐真菌对活性艳红染料X-3B的脱色实验研究

探讨了白腐真菌对活性艳红染料X-3B废水的脱色效果。实验结果表明白腐真菌可以有效地对染料废水进行脱色。白腐真菌在空气曝气培养条件下,比在空气静置培养状态下具有更强的脱色降解能力;而且当在染料废水中加入一定量的碳源物质(葡萄糖)能提高白腐真菌脱色能力。最后,通过考察细胞外液对染料废水的脱色效果,表明白腐真菌对染料进行脱色的核心体系位于细胞体外。实验结果对白腐真菌在环境工程中的直接应用具有一定的价值。     

基于元胞自动机的复杂建筑物中人员逃生模型研究

针对复杂建筑物中人群安全疏散问题,在原有的元胞自动机行人流模型基础上,利用不同人员行进速度、不同方向行进速度的差异以及疏散连续性等特征优化该模型,使其在模拟逃生规律和疏散时间方面更加合理、可靠。通过多组人群行进速度测定试验,利用曲线拟合方法,获取不同属性人群向不同高度的台阶行进的速度,并制定台阶等级划分规则,优化人员速度计算方法,结合累积位移量,构建复杂建筑元胞自动机模型。利用Matlab软件建立原有疏散模型及复杂建筑元胞自动机模型,分别模拟某海豚表演馆疏散情况。结果表明,复杂建筑元胞自动机模型的模拟数据与实际演习数据相比,在疏散总时间方面存在5%~8%相对偏差,相比原有疏散模型,在模拟复杂建筑疏散问题中更具说服力。     

河岸材料对河流有机污染物降解能力的影响

研究了干砌石、浆砌石、蜂巢格宾和生态砖等河岸材料对河流有机污染物降解能力的影响.4种材料中,以生态砖为河岸的河流中总有机碳(TOC)沿程降解率分别是蜂巢格宾和浆砌石的6.14和3.15倍(p<0.05);生态砖、干砌石和蜂巢格宾河段中溶解性有机碳(DOC)沿程降解率分别是浆砌石的10.68、6.60和6.08倍(p<0...     

Coupling a settlement growth model with an agro-economic land allocation model for securing ecosystem services provision

Mountain landscapes are undergoing rapid land-use changes. Settlement expansion, the intensification of agricultural land-use practices, and farmland abandonment result in a decline of natural and semi-natural habitats and the related ecosystem services (ES). In this context, spatial planning has emerged as a key instrument for the management of ES provision. To better understand trade-offs and interactions between settlement growth and ES provision in a spatially explicit manner, we present a new modeling framework coupling an agent-based, agro-economic optimization model and a cellular-automata-based settlement growth model. The framework is applied in an inner alpine valley in the Valais, Switzerland, which experienced rapid settlement growth in recent years. Results demonstrate how the model framework allows support of local planning processes. Particularly cooperation among municipalities and an explicit consideration of ES can inform spatially explicit ES trade-off decisions under increasing demand for land. We conclude that better informed spatial planning processes support ES provision.     

天津市滨海新区城市形态演化模拟及驱动力分析

基于TM遥感影像、城市规划图等数据,利用logistic CA模型,模拟了2005~2010年天津市滨海新区城市形态演化,经过模拟面积和Lee Sallle指数两个指标的精度评价后,定量分析了新版总规实施后城市形态演化的驱动力。实证研究表明：滨海新区城市形态扩展迅速,驱动力大小依次是自然环境、经济发展、交通带动、城市规划引导;其中交通驱动力中,影响最强烈的依次是火车站、城市的道路、高速出入口、县乡道、航道、省道。因此提出：城市规划必须顺应城市形态发展的规律,把握好可控的关键驱动力,科学预测城市形态发展和提出城市规划方案,做到积极有效的引导城市形态发展     

In vitro evaluation of cellular influences induced by stable fullerene C70 medium dispersion: Induction of cellular oxidative stress

Fullerene is one of the nanocarbons that is expected to have applications to life science, such as nanomedicines. An understanding of the cellular influences of fullerene is essential for its application to life science. Although C₆₀ and C₇₀ are both known as major fullerenes, most previous reports about the cellular influences of fullerene are about C₆₀. Thus we evaluated the cellular influences caused by C₇₀. A stable and uniform C₇₀-medium dispersion was prepared. The dispersion was stable for the experimental period. Mitochondrial activity (MTT assay), colony forming ability (clonogenic assay), induction of oxidative stress (intracellular ROS and lipid peroxidation levels) and cellular uptake (TEM observation) in human keratinocyte HaCaT and lung carcinoma A549 cells exposed to C₇₀ were examined. C₇₀ did not influence mitochondrial activity. On the other hand, C₇₀ dispersion inhibited colony formation at the concentration of 25.2 μg mL⁻¹. Exposure to C₇₀ dispersion caused an increase in intracellular ROS and lipid peroxidation levels. The induction of intracellular ROS level was inhibited by pre-treatment of the cells by antioxidants. TEM observations of C₇₀ exposed cells showed cellular uptake of C₇₀. These results were similar to the cellular influences caused by C₆₀ which were reported by us previously. Although C₇₀ did not cause cell death, it caused the induction of intracellular oxidative stress.