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91.
陕西关中地区城市灾害评价   总被引:8,自引:2,他引:8  
杜兴信  李博 《灾害学》1994,9(3):46-52
本文在详细分析关中地区六个大中城市的主要自然灾害和城市地质灾害的基础上,分别评价了各种灾害造成的经济损失,各个城市的灾害危险性、易损性和抗灾能力,并结合防灾对策对城市进行了综合分类。  相似文献   
92.
我国北方稻区稻飞虱的成灾机制:一个假说   总被引:6,自引:0,他引:6  
翟保平 《灾害学》1995,10(3):23-28
本文通过对大量文献资料的综合分析,从飞虱的飞行特性和北迁运载气流入手,以东亚大气低层环流为背景审视飞虱在有限时间内远迁北方致灾的成因机制,提出了以北上低空急流的时空变化与南方大发生虫源迁出期(区)相吻合、其前沿所至与北方迁入区相一致作为北方稻虱成灾的启动因子的假说.并提出了验证该假说的研究方法和技术路线,为揭示北方稻虱成灾的奥秘,完善灾变监测技术和预警系统奠定了基础。  相似文献   
93.
Results of breeding bird censuses in 1979 and 1980 were used to compare the relationships of both species and guilds to forest habitats in the White Mountains of New Hampshire. Several age classes of 11 forest cover types were studied: northern hard-woods (Fagus-Betula-Acer), spruce (Picea), spruce-fir (Picea-Abies), birth (Betula), swamp hardwoods (Acer-Pinus-Tsuga), pine (Pinus strobus andP. resinosa), balsam fir (Abies), aspen (Populus tremuloides andP. grandidentata), northern red oak (Quercus), oak-pine (Quercus-Pinus), and hemlock (Tsuga). All types were even-aged; only northern hardwoods had an additional uneven-aged condition. Forest cover types were also pooled to consider generalized habitats: hardwoods, mixed forest, or softwoods. Results of ordinations based on censuses of 74 bird species indicate that foraging guilds are more related to general cover types than are nesting substrate guilds, but bird species reflect habitat differences to a greater degree than do either guild scheme. Also, considerable overlap occurs in bird species distribution between hardwoods and mixed forests; softwoods show little overlap with other types. Discriminant function and classification analyses revealed that bird species composition can be used to correctly classify general forest habitats more accurately (83.8%) than either foraging (63.2%) or nesting substrate guilds (58.4%). These results indicate that, of the habitats studied, avian species compositions are more characteristic than are foraging or nesting substrate guild composition, which tend to be similar across forest habitats.  相似文献   
94.
以地市州为基本经济单元,以1999年主要相对指标为依据,通过综合值测算法,将全省划分为四类经济发展水平不同的地区,对四类地区平均总量指标、相对指标进行了对比分析,并揭示了其空间分布特征,简要分析了各类地区经济发展的条件和方向;以1999年、1978年各地市州GDP为例,对比分析了四川省区域经济不平衡发展的动态性特征。  相似文献   
95.
三论灾害研究的理论与实践   总被引:150,自引:35,他引:150  
在作者分别于 1991年发表的《论灾害研究的理论与实践》和 1996年发表的《再论灾害研究的理论与实践》的基础上 ,评述了最近 6年来灾害科学研究的进展 ,提出了灾害科学的基本框架 ,进一步完善了“区域灾害系统论”的理论体系 ,提出了当前灾害科学的主要学术前沿问题。文章并就资源开发与灾情形成机理与动态变化过程进行了综合分析 ,阐述了区域灾害的形成过程 ,进一步从区域可持续发展的角度 ,就建设安全社区 (区域 )提出了“允许灾害风险水平”的区域发展对策。  相似文献   
96.
ABSTRACT: River Environment Classification (REC) is a new system for classifying river environments that is based on climate, topography, geology, and land cover factors that control spatial patterns in river ecosystems. REC builds on existing principles for environmental regionalization and introduces three specific additions to the “ecoregion” approach. First, the REC assumes that ecological patterns are dependent on a range of factors and associated landscape scale processes, some of which may show significant variation within an ecoregion. REC arranges the controlling factors in a hierarchy with each level defining the cause of ecological variation at a given characteristic scale. Second, REC assumes that ecological characteristics of rivers are responses to fluvial (i.e., hydrological and hydraulic) processes. Thus, REC uses a network of channels and associated watersheds to classify specific sections of river. When mapped, REC has the form of a linear mosaic in which classes change in the downstream direction as the integrated characteristics of the watershed change, producing longitudinal spatial patterns that are typical of river ecosystems. Third, REC assigns individual river sections to a class independently and objectively according to criteria that result in a geographically independent framework in which classes may show wide geographic dispersion rather than the geographically dependent schemes that result from the ecoregion approach. REC has been developed to provide a multiscale spatial framework for river management and has been used to map the rivers of New Zealand at a 1:50,000 mapping scale.  相似文献   
97.
杨桂山 《灾害学》1993,8(2):53-58
本文在总结长江口地区现状盐水入侵时空变化规律的基础上,着重分析了在未来海平面上升、长江东线南水北调和三峡水利枢纽工程以及长江口北支综合整治等因素影响下,南支河段盐水入侵强度的变化趋势。  相似文献   
98.
99.
广东沿海地区海平面上升影响综合评估   总被引:3,自引:0,他引:3  
从系统的角度出发,建立了海平面灾害综合评估因子指标体系,引入了抗灾能力指数的概念,提出了一个综合评估模型,并以广东省沿海地区为例进行了海平面上升影响综合评估,结果表明,由于模型中考虑了抗灾能力指数,变被支评估为主动评估,使海岸灾害风险等级的评估结果更符合实际,评估结构可用于指导宏观抗灾,救灾,减灾等活动,该模型已用于广东海平面的地理信息系统(光盘)。  相似文献   
100.
ABSTRACT

This paper solves an optimal generation scheduling problem of hybrid power system considering the risk factor due to uncertain/intermittent nature of renewable energy resources (RERs) and electric vehicles (EVs). The hybrid power system considered in this work includes thermal generating units, RERs such as wind and solar photovoltaic (PV) units, battery energy storage systems (BESSs) and electric vehicles (EVs). Here, the two objective functions are formulated, i.e., minimization of operating cost and system risk, to develop an optimum scheduling strategy of hybrid power system. The objective of proposed approach is to minimize operating cost and system risk levels simultaneously. The operating cost minimization objective consists of costs due to thermal generators, wind farms, solar PV units, EVs, BESSs, and adjustment cost due to uncertainties in RERs and EVs. In this work, Conditional Value at Risk (CVaR) is considered as the risk index, and it is used to quantify the risk due to intermittent nature of RERs and EVs. The main contribution of this paper lies in its ability to determine the optimal generation schedules by optimizing operating cost and risk. These two objectives are solved by using a multiobjective-based nondominated sorting genetic algorithm-II (NSGA-II) algorithm, and it is used to develop a Pareto optimal front. A best-compromised solution is obtained by using fuzzy min-max approach. The proposed approach has been implemented on modified IEEE 30 bus and practical Indian 75 bus test systems. The obtained results show the best-compromised solution between operating cost and system risk level, and the suitability of CVaR for the management of risk associated with the uncertainties due to RERs and EVs.  相似文献   
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