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排序方式: 共有341条查询结果,搜索用时 31 毫秒
91.
Peng Gao Pengfei Li Baili Zhao Ruirui Xu Guangju Zhao Wenyi Sun Xingmin Mu 《水文研究》2017,31(26):4639-4646
Environmental change resulting from intensified human interventions and climate change has impacted the hydrological function of many large river systems, largely altering the production and transport of run‐off and sediment. It is thus vital to quantitatively evaluate the influence of climate change and human activities on streamflow and sediment discharge. Water balance equations, hydrological models, and comparative analyses are commonly used to fulfil this need. Double mass curves (DMCs), being one useful method for comparative analyses, are characterized by low data requirements and high transferability, and thus more practical than water balance equations and hydrological models for hydrologic benefit evaluations. However, the detailed derivation procedure of the DMC has, to date, yet been described in literature. Moreover, in previous studies, changing points of the DMC were determined either rather empirically or as the changing point of streamflow or sediment discharge (i.e., precipitation was not considered). Hence, the changing point detected may be subject to inaccuracies. This paper, for the first time, comprehensively detailed the derivation procedure of the DMC; a new way was proposed to quantitatively examine the changing point of the DMC; an example was also given to demonstrate the use of the DMC in the hydrologic benefit evaluation. It is hopeful that the method given in our paper will be widely adopted by future studies as a standard procedure to derive and use the DMC. 相似文献
92.
勘探效益法预测油气资源的原理及应用 总被引:3,自引:0,他引:3
随着油气勘探的深入、勘探程度的不断提高,未发现的剩余油气资源不断降低.如何准确预测高勘探程度-成熟探区的剩余油气资源,成为石油投资者和油气资源评价工作者关注的焦点.在详细探讨勘探效益法预测油气资源的原理、方法、操作流程及存在的问题的基础上,运用勘探效益法对苏北盆地高邮凹陷的剩余可探明储量进行了预测.研究表明,高邮凹陷的剩余可探明储量约为6 773×104 t,仍具有一定的勘探潜力;实践证明,由于勘探效益法合理回避了油气成因的机理问题,减少了资源评价工作中人为因素的影响,使资源评价的结果更为客观. 相似文献
93.
94.
非法演绎作品保护新论 总被引:1,自引:0,他引:1
董慧娟 《广东海洋大学学报》2008,28(2):29-32
总结世界各国立法和我国学者的观点,并结合著作权法的立法价值,提出:非法演绎作品应受著作权法保护,而不宜以民法的不当得利制度进行保护。 相似文献
95.
1999年在四川省德阳市绵竹县发生了两次5.0级地震.其中1999年11月30日绵竹汉旺5.0级地震前,德阳市地震局对该次地震的时问、地区、震级三要素做出了准确的短临预报.该项预报在人口稠密经济发达的四川德阳地区成功实现,取得了良好的社会和经济效益,得到了中国地震局,德阳市人民政府的充分肯定,并予以表彰和奖励. 相似文献
96.
97.
洞庭湖湿地资源退化的生态经济损益评估 总被引:21,自引:2,他引:19
洞庭湖湿地是中国最大的淡水湿地生态系统之一,湿地资源十分丰富,但由于人类不合理的开发利用,导致湿地生态系统严重退化,湿地生态服务功能价值受损,制约了湖区经济的可持续发展。在实地调查和试验的基础上,依据生态经济学的理论和方法,对洞庭湖湿地因资源退化引起的一系列自然灾害和生态灾害所造成的湿地生态功能损失进行了价值损益评估,由此得出湿地资源退化对湖区经济可持续发展所造成的损失;并指出只有恢复洞庭湖区湿地生态环境,保护好洞庭湖区湿地资源,才能实现洞庭湖区湿地资源的可持续利用,保证湖区经济的可持续发展。 相似文献
98.
Recent destructive flood events and projected increases in flood risks as a result of climate change in many regions around the world demonstrate the importance of improving flood risk management. Flood-proofing of buildings is often advocated as an effective strategy for limiting damage caused by floods. However, few empirical studies have estimated the damage that can be avoided by implementing such flood damage mitigation measures. This study estimates potential damage savings and the cost-effectiveness of specific flood damage mitigation measures that were implemented by households during major flood events in France. For this purpose, data about flood damage experienced and household flood preparedness were collected using a survey of 885 French households in three flood-prone regions that face different flood hazards. Four main conclusions can be drawn from this study. First, using regression analysis results in improved estimates of the effectiveness of mitigation measures than methods used by earlier studies that compare mean damage suffered between households who have, and who have not, taken these measures. Second, this study has provided empirical insights showing that some mitigation measures can substantially reduce damage during floods. Third, the effectiveness of the mitigation measures is very regional dependent, which can be explained by the different characteristics of the flood hazard in our sample areas that experience either slow onset river flooding or more rapid flash and coastal flooding. Fourth, the cost-efficiency of the flood damage mitigation measures depends strongly on the flood probability faced by households. 相似文献
99.
100.
基于行为与结果的土地整治项目绩效评价研究 总被引:6,自引:0,他引:6
目前我国土地整治项目绩效评价研究多基于项目实施评价或项目效益评价,缺乏可操作性。该文将实施者的行为过程与实施结果相结合,对土地整治项目绩效评价的内涵及内容进行界定,分别从土地整治项目的实施绩效(包括资金使用、管理规范、工程实施等情况)及效益绩效(包括经济效益、社会效益和生态效益)构建了土地整治项目绩效评价体系,并以河南省两个典型土地整治项目为例进行实证研究。将土地整治项目的实施评价与效益评价相结合,便于较全面地对项目进行绩效评价,所构建的指标体系基本合理。 相似文献