洪涝灾害条件下疏散交通生成预测方法

为有助于有关部门更准确预测洪涝灾害受灾民众的疏散量,结合非集计数据和集计数据的优点,提出分区集计数据的概念,设计了受灾区域分区方法,并通过意向偏好(SP)调查法对我国居民在洪涝条件下疏散交通需求数据进行调查。在此基础上,引入BP神经网络建立基于分区集计数据的疏散交通生成预测模型。利用调查数据进行实证分析发现,所设计方法取得了较好的预测效果,鲁棒性较好,平均相对预测误差仅为1.8%,其预测效果明显优于现有的非集计和整集计模型。     

Linking Land Cover and Water Quality in New York City’S Water Supply Watersheds

The Catskill/Delaware reservoirs supply 90% of New York City’s drinking water. The City has implemented a series of watershed protection measures, including land acquisition, aimed at preserving water quality in the Catskill/Delaware watersheds. The objective of this study was to examine how relationships between landscape and surface water measurements change between years. Thirty-two drainage areas delineated from surface water sample points (total nitrogen, total phosphorus, and fecal coliform bacteria concentrations) were used in step-wise regression analyses to test landscape and surface-water quality relationships. Two measurements of land use, percent agriculture and percent urban development, were positively related to water quality and consistently present in all regression models. Together these two land uses explained 25 to 75% of the regression model variation. However, the contribution of agriculture to water quality condition showed a decreasing trend with time as overall agricultural land cover decreased. Results from this study demonstrate that relationships between land cover and surface water concentrations of total nitrogen, total phosphorus, and fecal coliform bacteria counts over a large area can be evaluated using a relatively simple geographic information system method. Land managers may find this method useful for targeting resources in relation to a particular water quality concern, focusing best management efforts, and maximizing benefits to water quality with minimal costs.The United States Environmental Protection Agency through its Office of Research and Development funded and managed the research described here. It has been subjected to Agency’s administrative review and approved for publication as an EPA document.     

长白山西坡风灾干扰区的恢复和保护

长白山西坡发生的灾害性风灾干扰,一方面给长白山自然保护区的森林资源造成巨大损失,同时也提出了如何加强保护和加速恢复的新课题。文中分析了风灾干扰区的更新格局和过程以及干扰后处理的有关问题,提出了从立地和景观水平促进更新恢复的保护措施     

黄土洞穴的环境灾害效应

黄土洞穴本身是一种地质灾害,对黄土地区的运输、管道、拦蓄水工程、厂房、民居等各类工业与民用建筑构成不同程度威胁;还可促发其它地质灾害的发生和发展,恶化黄土高原地区的生态环境和地质环境。文章根据野外和室内研究所积累的资料,对黄土洞穴的地质灾害效应以及环境变化效应进行了初步研究。其研究成果不仅为黄土洞穴工程灾害的防治提供科学依据,而且还可进一步了解黄土地区水土流失的发育规律及其第四纪以来的地质环境变化状况。     

提高高职院校学生竞争力的途径

为了应对国际挑战，为了促进高职学生就业及构建和谐社会，高职院校应在专业设置，课程安排，职业教育与培养人文精神并重等几方面着眼来对学生进行全面塑造。     

地震灾害与地震预报——写在邢台地震40周年之际

本文分析了我国的地震灾害，阐述了近代地震灾害的特点和发展趋势，指出地震预报既是强烈的社会需求，也是全球性的科学难题，最后较为全面地介绍了我国地震预报的主要进展。     

小城镇的生态环境保护

在城镇化不断发展的进程中，小城镇的生态环境日益恶化。分析了小城镇生态环境存在的问题，提出了应采取的生态环境保护规划与对策。     

编制滇池流域水污染防治"十一五"规划的初步设想

从回顾滇池流域水污染防治“九五”计划和“十五”计划的编制入手,分析了1995、2000、2005年滇池流域的水污染变化趋势,提出了编制“十一五”规划的初步设想。     

合成氨装置重点部位的安全管理及防范措施

对安庆分公司化肥厂合成氨装置 4年以来的运行及安全管理情况作了综述 . 对装置的重点 监督部位加强技术型管理 , 并实行了一系列行之有效的安全防范措施 , 使之达到了国内同类 型装置先进水平 .     

Yellow River Valley flood and drought disaster:spatial-temporal distribution predictionand early-warning

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