石家庄市一次大气重污染过程的边界层特征和成因分析

针对石家庄市2015年12月5—14日出现的重污染过程,利用石家庄市逐日地基微波辐射计、风廓线雷达、地面气象观测资料以及同期的污染物观测资料,分析了重污染过程期间大气边界层温度、湿度、风变化特征及对PM_(2.5)的影响,采用Hysplit后向气团轨迹模式对污染来源进行分析。此次重污染以局地排放为主要形成源,期间冷空气势力弱,地面日平均风速均在1.5 m/s以下,日平均相对湿度均在70%以上,风速小、湿度大,稳定的大气环流形势为重污染提供了持续稳定的大气环境背景。逆温形成及快速增厚导致重污染开始,逆温层平均厚度为683 m,逆温层厚、强、不易消散,导致重污染持续时间长、污染重。近地面小风层厚(平均700 m左右),通风能力弱,导致污染物难以稀释扩散。同时近地层湿度大、厚度厚,使得PM_(2.5)更容易形成和积累,对重污染加重起到了促进作用。     

超材料在舰船电磁环境控制中的应用探索

首先阐述了国内外水面舰船电磁干扰控制技术和雷达波隐身技术的发展现状,然后介绍了近年来电磁超材料(Metamaterial)的研究进展,并对其可应用于水面舰船总体电磁环境控制方面的潜在应用进行挖掘与探索,最后对未来水面舰船的雷达波隐身性设计和电磁兼容性设计的一体化解决方案进行了展望。     

SAR影像洪水淹没范围深度学习提取方法

为提高洪涝灾害应急救援辅助决策能力,快速提取洪水淹没范围,提出一种基于深度学习的合成孔径雷达(SAR)影像洪水淹没范围提取方法。首先,基于DeepLab v3+模型,建立合成孔径雷达(SAR)影像洪水淹没范围提取模型;然后,针对SAR影像标注数据获取困难的问题,提出一种基于光学影像水体指数的半自动化标注样本制作方法,该方法大幅度减少标注工作的人工量和所需时间;最后,采用Sentinel-1卫星影像验证洪水淹没范围提取模型准确度。结果表明:提出的洪水淹没范围提取模型对复杂地表适应性较强;相比于自适应阈值方法,其识别精度更高,对遥感影像中的水体边缘、小面积水体、细长线状水体识别效果更优,该模型平均交并比为0.83。     

FCM下暴雨干扰地铁系统脆弱性演化分析

为预防暴雨干扰下地铁安全事故,提出一种基于模糊认知图（FCM）的根本原因分析方法,评估地铁系统脆弱性;利用文本挖掘和专家访谈,构建由人的行为、设备设施、安全管理、应急救援、环境及脆弱性6个概念组成的因果模型,在FCM框架内模拟地铁系统脆弱性。结果表明：5种因素均与地铁系统脆弱性存在强相关性,其相关性大小为：安全管理>人的行为>应急救援>设备设施>环境;设备设施是疑似影响地铁系统脆弱性最根本的原因,此外,应注意监测应急救援储备情况及地铁运行环境;地铁系统脆弱性对于安全管理、人员行为的变动最为敏感。该方法可运用于地铁安全事故的预防,从而提高地铁系统安全管理水平。     

围垦堤防探地雷达法检测仿真分析与应用

为精准判断围垦堤防架空隐患的位置和范围,结合探地雷达检测技术的优点,基于时域有限差分法(FDTD),对探地雷达电磁波的传播特征进行数值模拟分析。主要研究时域有限差分法的差分形式、二维空间内的时域差分方程、数值稳定性及吸收边界条件的设定等问题。对围垦堤防可能存在的几种隐患形式进行正演模拟,通过分析雷达电磁波幅值变化,讨论其相应的剖面图像特征,并通过开展室内模拟试验和现场检测工作研究对正演模拟结论进行验证。研究结果表明：正演模拟可实现探地雷达典型形状目标的识别,为提高现场检测图像解释的精度和准确性提供理论参考。     

Comparing Landslide Maps: A Case Study in the Upper Tiber River Basin, Central Italy

/ The preparation of landslide maps is an important step in any landslide hazard assessment. Landslides maps are prepared around the world, but little effort is made to assess their reliability, outline their main characteristics, and pinpoint their limitations. In order to redress this imbalance, the results of a long-term research project in the Upper Tiber River basin in central Italy are used to compare reconnaissance and detailed landslide inventory maps, statistical and geomorphologically based density maps, and landslide hazard maps obtained by multivariate statistical modeling. An attempt is made to discuss advantages and limitations of the available maps, outlining possible applications for decision-makers, land developers, and environmental and civil defence agencies. The Tiber experiment has confirmed that landslides can be cost-effectively mapped by interpreting aerial photographs coupled with field surveys and that errors and uncertainties associated with the inventory can be quantified. The experiment has shown that GIS makes it easy to prepare landslide density maps and facilitates the production of statistically based landslide hazard models. The former supply an overview of the distribution of landslides that is easily comprehended but do not provide insight on the causes of instability. The latter, giving insight into the causes of instability, are diagnostically powerful, but are difficult to prepare and exploit.     

Twenty years of salt marsh succession on a Dutch coastal barrier island

After a formerly grazed salt marsh was released from cattle grazing, changes in plant species composition were monitored for 20 yr, using vegetation maps and permanent plots. Three areas, differing in age and nutrient status were compared. The number of plant species and plant communities decreased.Elymus athericus (Elytrigia pungens) became dominant in most plant communities after 5–20 yr on the oldest and most productive salt marsh. In younger areas it took more time forE. athericus to become dominant. At least 7 cm of clay seemed to be a prerequisite for this plant species to increase in dominance. The results from monitoring over decades are discussed in view of the knowledge on succession over centuries as derived from a chronosequence.     

全国大气润湿时间分布分析软件开发

软件以小方块在地图上标注全国195个地区的实际位置,按ISO 9223标准对各地区的年润湿时间进行分级,并以不同的颜色对应不同的等级。使用软件可查询1991年至2000年全国195个地区大气润湿时间的分布状况;不同临界相对湿度的润湿时间;各年润湿时间的变化规律情况,包括10年润湿时间的平均值和标准差;年润湿时间在各温度段所占的比例。     

城市安全生产画像构建与应用探讨

为使城市安全生产监管部门及时掌控安全生产状态,实现监管资源的合理调配与工作部署,本文针对城市安全生产领域监管系统多、数据量庞大、数据分析不深入等问题,利用城市安全生产画像的表现形式,对城市安全生产画像构建的各个环节进行针对性探讨;以某地安全监管部门为例,整合该地下属8个区域的执法检查和处罚数据,构建辅助当地安全生产监管力量部署的多维画像,并通过脸谱聚类图这种可视化形式来表征此地区监管力量的局部与总体特征。结果表明:城市安全生产画像,是一种有效的大数据分析手段,有助于监管部门迅速掌握城市整体及局部安全状况,预判安全趋势,合理部署监管资源,降低事故风险概率,显著提高城市安全生产管理水平。     

A new multiple-risk map approach to solve process plant layout considering safety and economic aspects

Mathematical models used to optimize the process plant layout (PPL) with risk reduction have four primary objectives, which are related to the minimization of land, pumping (pipe system), protection system devices, and risk costs. Moreover, these models are of two types: continuous plane models (CPM) and grid-based models (GBM); however, the nonconvexity of the CPM models makes difficult to achieve the global optimum, because it is formulated as Mixed-Integer Nonlinear Programming (MINLP). Thus, the risk map approach has been implemented with the grid-based models to solve problems of process plant layout focused on finding the best possible solution. However, these risk map formulations present important limitations, mainly related with the use of protection devices and the occupied area. Therefore, a new GBM-MILP formulation is proposed to optimize the selection of protection devices and minimize the occupied area. The risk is reduced through the investment on safety devices instead of considering the increase of separation distances. The proposed model was used to solve the layout problem of an ethylene oxide process, and the results was compared with a process layout reported in the literature. The results show that the model can provide the best possible solution; however, the time spent in the calculation is considerably greater than that reported for continuous plane models. Finally, the model can be used by decision-makers to evaluate different layout options for several explosion scenarios, during the early stages of the plant design.