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81.
采用华丰矿1409工作面电磁辐射观测数据,应用相空间重构法计算了5次矿震前后系统混沌吸引子的关联维数D2。研究结果表明:电磁辐射时间序列具有混沌特征,混沌系统的自由度在2~26之间。矿震发生前,混沌吸引子的关联维数D2先升后降,矿震过程中系统有降维现象。研究结果对认识矿震过程中煤岩体产生的电磁辐射信号的非线性特征和进行矿震预报具有一定的参考价值。 相似文献
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赵学友 《铁路节能环保与安全卫生》2021,(1):32-35
针对某车站供暖成本升高和污染物排放等问题,从热源改造和建筑维护结构改造2个方面提出节能技术改造方案,通过对机组运行情况和围护结构改造情况的现场测试,得到节能技术改造效果良好的结论,并从节能效益、经济效益和环保效益3个方面对站区节能技术改造方案效果进行分析. 相似文献
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基于国内外灾害经济研究与管理实践的启示 总被引:1,自引:0,他引:1
中外学者从不同视域对灾害经济与管理问题进行了研究,形成了一些有代表性的观点。各国政府在防灾减灾、灾后重建等方面也积累了大量的经验。这些观点和经验为我们深入研究灾害管理机制奠定了基础,结合汶川8.0级地震导致的惨重损失及灾后重建出现的问题,阐述了构建我国以人为本的灾害管理机制和可持续重建地震灾区的基本对策。 相似文献
85.
Investigation of head injuries by reconstructions of real-world vehicle-versus-adult-pedestrian accidents 总被引:2,自引:0,他引:2
A sizeable proportion of adult pedestrians involved in vehicle-versus-pedestrian accidents suffer head injuries, some of which can lead to lifelong disability or even death. To understand head injury mechanisms, in-depth accident analyses and accident reconstructions were conducted. A total of 120 adult pedestrian accident cases from the GIDAS (German in-depth accident study) database were analyzed, from which 10 were selected for reconstruction. Accident reconstructions initially were performed using multi-body system (MBS) pedestrian and car models, so as to calculate head impact conditions, like head impact velocity, head position and head orientation. These impact conditions then were used to set the initial conditions in a simulation of a head striking a windshield, using finite element (FE) head and windshield models. The intracranial pressure and stress distributions of the FE head model were calculated and correlated with injury outcomes. Accident analysis revealed that the windshield and its surrounding frames were the main sources of head injury for adult pedestrians. Reconstruction results indicated that coup/contrecoup pressure, Von Mises and shear stress were important physical parameters to estimate brain injury risks. 相似文献
86.
Mac Nally R 《Journal of environmental management》2008,88(4):1202-1211
Many native bird species in production landscapes of south-eastern Australia demonstrably are declining, with loss of native vegetation as the major cause. Our biodiversity management objectives must be to increase the probabilities of persistence of birds that should occur in the landscape. To do so, there needs to be extensive amounts of new plantings. However, one must be conscious that: (1) new plantings in the impoverished soils and increasing aridity of southern Australia will take many decades to mature, and, also, will offer suitable habitats for a sequence of different species over the course of that maturation process; and (2) much existing vegetation is senescent or will be in a few decades' time. Recent landscape rebuilding models do not explicitly consider maturation time-lags. These hystereses in habitat maturation may create 'bottlenecks' at future times (e.g. in 50yr) that might prevent some species from persisting in whole landscapes even though such landscapes may be much more suitable in 100yr than now. There are several critical issues: (1) species differ in habitat needs and even one species may require different kinds of habitats for foraging and for breeding; (2) landscapes must be conceived, and managed, as spatial and temporal mosaics to allow for persistence of the full set of species that should occupy them, meaning that senescing and replanted habitats may need to be juxtaposed; and (3) in certain particularly problematic landscapes, some highly productive agricultural lands may need to be used for providing habitat because maturation can be fast-tracked in fertile, well-watered locations. The problem is a complex one of scheduling and placement, and its optimization presents major theoretical and analytical challenges. 相似文献
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Standardising and mapping open-source information for crisis regions: the case of post-conflict Iraq
Painting an accurate picture of the situation on the ground in countries in crisis is vital for the efficiency of humanitarian aid and reconstruction agencies. This study describes a method for standardising and mapping the plethora of open-source information. The test site for the study is post-conflict Iraq. Important information on aid distribution, reconstruction and security in Iraq can be derived from the reports of humanitarian aid agencies and the media, before being formatted, inserted into a database and mapped. The product is a visual, cartographic structure of otherwise random information, showing which organisations are working in the country, which thematic and geographic areas are being prioritized in the field, and which areas most frequently experience security events. This type of mapping not only highlights the overall working environment within different parts of the country, but it may also serve as a decision-making tool for donors and humanitarian aid agencies planning to deploy personnel. 相似文献
90.
我国北方地区冬季漫长而寒冷,夏季短暂而温暖,年平均气温低,气温年较差大,开展北方寒冷地区景观水体研究对完善生态系统保护体系及可持续发展具有重要意义。针对北方寒冷地区景观水体环境特征,以牡丹江市南湖水系为例,开展水体水质及水环境特征研究,进行北方寒冷地区景观水体的生态重建与景观修复技术、水资源管理技术、越冬策略研究,并根据工程实践结果,提出北方景观水体水质保障的对策和建议,对北方地区景观水体保护、流域可持续发展具有借鉴意义。 相似文献