基于卫星数据研究兰州市NO2时空分布特征以及冬季NOx排放通量

搭载在EOS AURA卫星上的OMI探测器由于其较高时空分辨率在大气痕量气体(O3,NO2,SO2)探测中得到广泛应用.利用2010~2012年OMI NO2柱浓度数据产品重构了兰州市以及周边地区NO2柱浓度分布,分析了其时空变化特征,并利用西南风场下NO2空间分布特征采用拟合方法研究了NOx冬季排放通量以及寿命.研究表明,NO2柱浓度空间分布呈现以兰州市为中心,浓度向四周扩散的特征;兰州市NO2柱浓度的年变化特征为12月达到最大浓度,8月达到最小浓度;2010~2012年NO2寿命分别为10.6,9.9,9.1h,NOx冬季排放通量分别为175.3, 183.7,179.9mol/s.其排放通量与兰州环境公报提供的氮氧化物排放通量数量级之间具有较好的一致性,说明利用卫星数据估算兰州的NOx通量方法的有效性.     

基于图像识别的建筑工人智能安全检查系统设计与实现

为提高建筑工人作业前安全检查的效率和效果,减少事故发生。以图像识别技术为核心支撑,提出了建筑工人智能安全检查系统的结构、功能及运行流程,并对系统运行效果进行了测试。研究和测试表明:该系统具备身份识别、安全装备检查、作业行为能力检查功能,能实现建筑工人作业前的自动、智能安全检查。该系统的身份识别正确率为83.75%、安全帽识别正确率为96.25%、安全带识别正确率为63.75%。该系统具有硬件投入低、检测速度快、准确性高、应用场景广泛的特点。     

Application of Remote Sensing in Detection of Ocean Oil Pollution

It is well known that the increase of surface tension due to the presence of oil slicks causes the surface wave motion is depressed or even disappeared, thus making the surface electromagnetically smoother. Therefore, the radar backscattered energy is correspondingly decreased. These damping effects is now well understood and such effects enables the oil slicks to be discernible from the radar image. in this paper, we are concerned with the digital technique that effectively delineates the oil slicks pattern from the SAR image. the detected pattern allows us to estimate the coverage of oil spillage. the technique is based on the fact that the oil slicks make a gray value surface in the image which is a concave area with a certain size. in order to identify correctly these oil slicks and suppress the speckle noise and other natural phenomena, an image pyramid with multi-resolution layers is generated sequentially from the original image. Then a top-down approach, which applies both first and second order derivative operators, the Difference of Gaussian (DoG) and the Laplace of Gaussian (LoG), to the image pyramid, is used to detect oil patches. Two ERS-1 SAR images acquired on August 5, 1994 and September 5, 1994, around Taiwan, were used for testing. Results indicate that the proposed method depresses the speckle noise and other sea noise signals, and enhances the oil slicks pattern clearly. the robustness to the empirical parameters introduced in this scheme was also demonstrated.     

卫星遥感监测近地表细颗粒物多元回归方法研究

对地基监测PM2.5和气象数据、MODISAOD卫星数据与NCEP FNL数据进行了处理分析,在与一元简单线性模型(模型1)进行对比的基础上,建立了适应于北京及其附近地区遥感监测近地面颗粒物(PM2.5)浓度的多元线性(模型2)和非线性(模型3)回归模型,并对模型进行了评价验证和遥感监测初步应用.结果表明:模型1,2,3分别能够解释PM2.5 32.5%,56.1%,62.7%的变异.反演的PM2.5浓度与站点监测值相关性分别为0.5488(R2=0.3012), 0.7449(R2=0.5549), 0.7431(R2=0.5523).对于站点监测PM2.5浓度63.1652μg/m3的均值,反演均方根误差RMSE分别为43.5562, 35.3321, 36.8450μg/m3.模型2和3中气象因子分别能够解释PM2.5 23.6%和12.6%的变异,说明了气象因子影响北京地区春季PM2.5-AOD关系的显著性.3种模型整体上都不同程度地存在着低值高估和高值低估的现象.     

Multispectral image analysis method to determine dynamic fluid saturation distribution in two-dimensional three-fluid phase flow laboratory experiments

The need for measuring dynamic fluid saturation distribution in multi-dimensional three-fluid phase flow experiments is hampered by lack of appropriate techniques to monitor full field transient flow phenomena. There is no conventional technique able to measure dynamic three-fluid phase saturation at several array points of the flow field at the same time. A multispectral image analysis technique was developed to determine dynamic NAPL, water and air saturation distribution in two-dimensional three-fluid phase laboratory experiments. Using a digital near-infrared camera, images of sand samples with various degrees of NAPL, water and air saturation were taken, under constant lighting conditions and within three narrow spectral bands of the visible and near-infrared spectrum. It was shown that the optical density defined for the reflected luminous intensity was a linear function of the NAPL and the water saturation for each spectral band and for any two and three-fluid phase systems. This allowed the definition of dimensionless lump reflection coefficients for the NAPL and the water phase within each spectral band. Consequently, at any given time, two images taken within two different spectral bands provided two linear equations which could be solved for the water and the NAPL saturation. The method was applied to two-dimensional three-phase flow experiments, which were conducted to investigate the migration and the distribution of LNAPL in the vadose zone. The method was used to obtain continuous, quantitative and dynamic full field mapping of the NAPL saturation as well as the variation of the water and the air saturation during NAPL flow. The method provides a non-destructive and non-intrusive tool for studying multiphase flow for which rapid changes in fluid saturation in the entire flow domain is difficult to measure using conventional techniques.     

基于DEM的SAR图像洪水水体的提取

星载雷达遥感已广泛应用于洪水灾害的监测和评估中。但是由于其阴影与水体严重混淆 ,使得从雷达图像中提取洪水水体较为困难。为此 ,本文探讨了在地形数据的支持下 ,实现星载SAR图像洪水水体半自动提取的方法。主要包括以下几步 :首先 ,对雷达图像进行滤波处理 ,并将其与地形数据匹配 ,从雷达图像中提取出初步的洪水水体范围 ;其次 ,利用地形数据生成DEM ,并根据雷达图像的成像参数和DEM生成相应的模拟雷达图像 ;最后 ,利用模拟雷达图像上的阴影 ,剔除被误提为洪水水体的阴影 ,从而实现洪水水体的准确提取。研究表明 ,该方法能有效地、半自动地将星载雷达图像上的洪水水体提取出来 ;同时 ,该方法可以用于多种星载多模式的雷达图像的洪水水体的识别提取 ,尤其对含山区的大范围洪水水体的半自动提取 ,更为适用。     

Comparing the Use of Indigenous Knowledge with Classification and Ordination Techniques for Assessing the Species Composition and Structure of Vegetation in a Tropical Forest

dentification of groups that are similar in their floristic composition and structure (habitat types) is essential for conservation and forest managers to allocate high priority areas and to designate areas for reserves, refuges, and other protected areas. In this study, the use of indigenous knowledge for the identification of habitat types in the field was compared against an ecological characterization of habitat types, including their species composition obtained by using classification and ordination techniques for a tropical landscape mosaic in a rural Mayan area of Quintana Roo, Mexico. Plant diversity data calculated from 141 sampled sites chosen randomly on a vegetation class’s thematic map obtained by multispectral satellite image classification were used for this propose. Results indicated high similarity in the categorization of vegetation types between the Mayan classification and those obtained by cluster and detrended correspondence analysis. This suggests that indigenous knowledge has a practical use and can be comparable to that obtained by using science-based methods. Finally, identification and mapping of vegetation classes (habitat types) using satellite image classification allowed us to discriminate significantly different species compositions, in such a way that they can provide a useful mechanism for interpolating diversity values over the entire landscape.     

聚硅酸金属盐复合絮凝剂的形貌研究

用扫描电镜(SEM)对聚硅酸金属盐复合絮凝剂进行了形貌观察,并用能谱仪(EDS)测定其组成,发现硼、铝和铁元素的加入能改变聚硅酸的形貌,提高其稳定性,并且增大了聚合物的聚合度;聚硅酸金属盐复合絮凝剂是其中各种元素之间相互作用所形成的结构、形貌均一的聚合物,而不是各自均聚物的混合物;硼、铝、硅和铁四种元素靠吸附、键合、配位等作用复合。     

烟气湍流效应对火灾图像探测的影响

烟气是火灾过程的重要物理现象,烟气的湍流效应是火灾图像探测的重要影响因素,分析了烟气湍流反应对火灾图像探测的影响,得出了一些烟气湍流效应的图像特征,为多参数特征的火灾探测提供了理论依据。     

中国火灾探测技术的现状及其发展趋势

对我国火灾探测技术进行讨论。随着社会的进步,建筑物结构的复杂化程度越来越高。对于高可靠性、智能化、快速响应的新型火灾探测技术的研究是火灾探测领域的研究热点和发展趋势。