最小生成树法在环境背景值识别中的应用

本文用最小生成树法解决环境中的聚类分析问题。该法用x~2距离系数矩阵描述样本变量间的相似关系,同时用Kruskal法构造最小生成树,最后以分类图的形式给出分类结果。     

苏州沿江生态城市群建设与景观生态整合

基于苏州沿江生态城市群建设的背景和景观生态条件分析,提出了建设有江南特色的苏州沿江景观生态格局的思路,即通过以水为核心,以"一江十道、五线、廿环"生态廊道和九大斑块为主的建设,构筑以农山郊野为背景的多等级网络式的沿江景观生态格局,从而整合区域生态景观,推动苏州沿江生态城市群建设。     

Development of a cloud condensation nuclei (CCN) counter using a laser and charge-coupled device (CCD) camera

A continuous flow streamwise thermal gradient cloud condensation nuclei (CCN) counter with an aerosol focusing and a laser-charge-coupled device (CCD) camera detector system was developed here. The counting performance of the laser-CCD camera detector system was evaluated by comparing its measured number concentrations with those measured with a condensation particle counter (CPC) using polystyrene latex (PSL) and NaCl particles of varying sizes. The CCD camera parameters (e.g. brightness, gain, gamma, and exposure time) were optimized to detect moving particles in the sensing volume and to provide the best image to count them. The CCN counter worked well in the particle number concentration range of 0.6–8000 #·cm^-3 and the minimum detectable size was found to be 0.5 μm. The supersaturation in the CCN counter with varying temperature difference was determined by using size-selected sodium chloride particles based on K?hler equation. The developed CCN counter was applied to investigate CCN activity of atmospheric ultrafine particles at 0.5% supersaturation. Data showed that CCN activity increased with increasing particle size and that the higher CCN activation for ultrafine particles occurred in the afternoon, suggesting the significant existence of hygroscopic or soluble species in photochemically-produced ultrafine particles.     

基于PSR和云理论的农用地生态环境评价——以广东省新兴县为例

论文采用PSR框架构建评价指标体系,利用云理论分别构建定量指标与定性指标的云模型,对农用地生态环境进行评价。以广东省新兴县为例,得出新兴县农用地生态环境分值为0.75,农用地生态环境良好。并将云理论与模糊规则进行对比,得出新兴县农用地生态环境分值分别为0.75和0.70,两者结果差异不大,但是结果表明云理论能完整表达评价问题中的不确定性,避免模糊规则中隶属度函数确定繁琐的问题。     

Using cluster analysis to explore mortality patterns associated with tropical cyclones

Understanding the circumstances and conditions surrounding disaster‐attributed deaths may contribute to designing and implementing emergency preparedness and response programmes. This paper introduces a three‐step cluster analysis of multiple binary variables to investigate mortality patterns related to tropical cyclones. It is designed to overcome the difficulties of performing cluster analysis in a disaster database that is composed in part of nominal variables and is unavoidably incomplete owing to missing information. The first step in the process codes all variables as binary data in order to accommodate the nominal variables. The second step calculates Spearman's rank correlation coefficients for pairs of variables. And the third step subjects the correlation coefficients to cluster analysis. Data related to 1,575 deaths attributed to tropical cyclones (also known as typhoons) that struck Taiwan between 2000 and 2015 are used to illustrate the method. The results yield two distinct groups of variables that are worthy of further exploration.     

Predicting the flammable region reach of propane vapor clouds

Liquified gas fuels are widely used around the world, and the growth of LNG and LPG consumption continues to increase. However, using these fuels can lead to accidents if they are released to the environment. Consequently, the challenge to control and predict such hazards has become an objective in emergency planning and risk analysis. In a previous article the “Dispersion Safety Factor” (DSF) was proposed, defined as the ratio between the distance at which the lower flammability limit concentration occurs and that corresponding to the visible contour of a vapor cloud. Its interest was demonstrated by applying it to the specific case of an LNG spill. With the appropriate modifications, this factor may be applied to the dispersion of other substances; in this communication it is applied to the atmospheric dispersion of propane, and two expressions are proposed to estimate it. Due to the similarity between the properties of both gases, these expressions could probably be applied as well to the dispersion of propylene.     

云计算在核安全分析中的应用研究

在进行核安全分析时,需要考虑核反应堆设计、运行、管理及计算评估等诸多方面的复杂问题。而人员进行风险评估会在很大程度上影响核电站的正常运行时间,并带来人因失误的不确定性增大。利用云计算,可以有效地解决核安全分析面临的资料繁杂,模型构造麻烦和信息不共通等缺点。提出核安全云的概念,将云计算与核安全分析结合起来,借助计算机平台对核电厂的选址定点、建造、调试、运行及退役过程中可能产生的风险进行分析计算,更全面的分析各种不利条件,及时地做出决策,可以有效的降低风险发生的概率以及降低计算成本,可更准确地实现核电站安全分析的目标。     

针对NPP VIIRS数据的云检测方法研究

为了获得新型红外成像辐射仪套件(Visible Infrared Imager Radiometer Suite, VIIRS)传感器准确的云掩码数据,克服当前VIIRS云检测算法在中国区域存在的部分缺陷.本研究通过分析当前较为成熟的中分辨率光谱成像仪(Moderate Resolution Imaging Spectroradiometer,MODIS)云掩码算法,结合VIIRS传感器的波段特性,提出了适合中国区域的云检测算法.针对1.38μm高(卷)云检测算法在高海拔区域存在的限制,本研究使用亮温进行辅助检测,降低因低水汽含量造成的误报;针对当前VIIRS M12-M13云检测阈值在我国存在误报的问题,对M12-M13差值云检测在我国适用范围和阈值进行了分析讨论,并使用亮温辅助M12-M13进一步克服地表二项性反射造成的干扰.使用中国区域的两景数据进行应用分析表明:亮温辅助1.38um高(卷)云检测能够较好的抑制地表污染,亮温辅助M12-M13差值云检测比当前VIIRS M12-M13云检测能更好的抑制误报.通过人工解译,将检测结果和解译结果做了对比分析,实例数据检测精度均高于85%,能够满足当前云检测精度要求.     

绿色经济发展总体评价与区域差异分析

依据联合国环境规划署提出的绿色经济指标框架,即“经济转型有效性”“资源利用绿色度”“进步和福祉实现度”3个方面,结合我国实际情况,建立了一套三级指标体系,并采用主成分分析、聚类分析、多元线性回归等方法,从横向和纵向2个维度分析了我国绿色经济发展状况. 结果表明:①我国30个地区绿色经济发展不均衡,绿色经济综合指标得分最高相差4.52,其中5个发展水平最低的地区均位于西部;②各地区内部3个指标也同样存在不平衡的问题;③1997—2011年,我国绿色经济发展的总体水平呈良好上升态势,绿色经济综合指标的年均增幅为42%,但某些经济总量发展领先的东部地区,在过去的15 a间绿色经济发展甚至出现倒退;④资源利用和环境保护是影响我国绿色经济发展的主要因素,其中“有效灌溉面积占耕地比重”指标的影响最大,其标准回归系数达到0.553.      

理论毒理学研究进展

毒理学是近代发展起来的科学,由于工农业生产的迅速发展,化学物质剧增,迄今登记在册的化学物质已超过2 600万种,每年还新增2 000多种,因此传统的毒性鉴定已远远不能满足时代的要求,针对各种化学物质的细致的毒理学研究更是难以实现。因此毒理学必须在理论层面实现突破,缩短研究时间,减少研究经费及人力、物力的消耗,同时可使化学物质得到更安全的应用。另外,动物保护已列入议事日程,不再允许大量使用动物做毒理方面的实验,这些促进了理论毒理学的发展。