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71.
高瓦斯矿井孤岛综放采空区遗煤自燃综合防治技术   总被引:12,自引:2,他引:10  
针对国阳二矿高瓦斯自燃煤层综放开采的实际情况,分析了"U+Ⅱ"型孤岛综放面采空区遗煤自燃特点及危险性。利用单元法对孤岛面的漏风状况进行了实测,并通过数值模拟分析了综放采空区内的漏风流场,根据采空区自燃"三带"的渗流风速确定了可能自燃带的范围,表明采空区漏风是"U+Ⅱ"型孤岛综放面采空区遗煤自燃的主要危险因素。在此基础上,结合实际情况系统地制定了以有效控制采空区漏风和重点发火区域注胶为主的综合防灭火技术措施,为有效控制综放采空区遗煤自燃,实现矿井高产高效、安全生产提供技术保障。实践表明,运用控制工作面风量与高抽巷负压、均压堵漏、压注胶体防灭火材料及加快工作面推进速度等综合防灭火技术防治高瓦斯矿井"U+Ⅱ"型孤岛综放面采空区遗煤自燃是可行的。  相似文献   
72.
从我国沿海岛屿旅游十几年的发展历程来看,各沿海岛屿由于所处的地理位置、历史条件、气候条件及资源与文化丰度差异,决定了其旅游发展水平与发展方式存在明显不同。从旅游发展主要驱动力角度,探讨了那些依托其独特旅游资源开发带动经济发展的岛屿经济发展模式。  相似文献   
73.
城市化与北京增温的协整分析   总被引:1,自引:0,他引:1  
城市增温现象和城市热岛效应对人居环境的影响日益显著,而城市化是否是城市增温现象的一个主要影响因素,为此。利用协整分析等经济计量方法研究城市化对城市增温现象的影响。协整分析是近年来计量经济学发展的最新成果,能够揭示变量之间存在着的长期均衡变动关系。分析发现,城市化因子与城市气候因子之间存在着协整关系。长期看北京市的年平均最低温度与人口密度基本上处于同步增长状态;短期内城市气温的变动受人口和城市化因素的影响较大。为此可知,北京市70年代以来,城市气温的升高基本上与城市化的发展相一致。二者具有长期协同变动的均衡关系。这些发现对我们制定减缓城市热岛效应的城市规划以及合理人口规模的城市发展战略都有很大的帮助。  相似文献   
74.
Mosley LM  Sharp DS  Singh S 《Disasters》2004,28(4):405-417
The effect of a cyclone (Ami, January 2003) on drinking-water quality on the island of Vanua Levu, Fiji was investigated. Following the cyclone nearly three-quarters of the samples analysed did not conform to World Health Organisation (WHO) guideline values for safe drinking-water in terms of chlorine residual, total and faecal coliforms, and turbidity. Turbidity and total coliform levels significantly increased (up 56 and 62 per cent, respectively) from pre-cyclone levels, which was likely due to the large amounts of silt and debris entering water-supply sources during the cyclone. The utility found it difficult to maintain a reliable supply of treated water in the aftermath of the disaster. Communities were unaware they were drinking water that had not been adequately treated. Circumstances permitted this cyclone to be used as a case study to assess whether a simple paper-strip water-quality test (the hydrogen sulphide, H(2)S) kit could be distributed and used for community-based monitoring following such a disaster event to better protect public health. The H(2)S test results correlated well with faecal and total coliform results as found in previous studies. A small percentage of samples (about 10 per cent) tested positive for faecal and total coliforms but did not test positive in the H(2)S test. It was concluded that the H(2)S test would be well suited to wider use, especially in the absence of water-quality monitoring capabilities for outer island groups as it is inexpensive and easy to use, thus enabling communities and community health workers with minimal training to test their own water supplies without outside assistance. The importance of public education before and after natural disasters is also discussed.  相似文献   
75.
Environmental decision-making and policy-making at all levels refers necessarily to synthetic, approximate quantification of environmental properties such as vulnerability, conservation status, and ability to recover after perturbation. Knowledge of such properties is essential to informed decision-making, but their definition is controversial and their precise characterization requires investments in research, modeling, and data collection that are only possible in the most developed countries. Environmental agencies and governments worldwide have increasingly requested numerical quantification or semiquantitative ranking of such attributes at the ecosystem, landscape, and country level. We do not have a theory to guide their calculation, in general or specific contexts, particularly with the amount of resources usually available in such cases. As a result, these measures are often calculated with little scientific justification and high subjectivity, and such doubtful approximations are used for critical decision-making. This problem applies particularly to countries with weak economies, such as small island states, where the most precious environmental resources are often concentrated. This paper discusses frameworks for a “least disappointing,” approximate quantification of environmental vulnerability. After a review of recent research and recent attempts to quantify environmental vulnerability, we discuss models and theoretical frameworks for obtaining an approximate, standardizable vulnerability indicator of minimal subjectivity and maximum generality. We also discuss issues of empirical testing and comparability between indicators developed for different environments. To assess the state of the art, we describe an independent ongoing project developed in the South Pacific area and aimed to the comparative evaluation of the vulnerability of arbitrary countries.  相似文献   
76.
Islands present a unique scenario in conservation biology, offering refuge yet imposing limitations on insular populations. The Kimberley region of northwestern Australia has more than 2500 islands that have recently come into focus as substantial conservation resources. It is therefore of great interest for managers to understand the driving forces of genetic structure of species within these island archipelagos. We used the ubiquitous bar‐shouldered skink (Ctenotus inornatus) as a model species to represent the influence of landscape factors on genetic structure across the Kimberley islands. On 41 islands and 4 mainland locations in a remote area of Australia, we genotyped individuals across 18 nuclear (microsatellite) markers. Measures of genetic differentiation and diversity were used in two complementary analyses. We used circuit theory and Mantel tests to examine the influence of the landscape matrix on population connectivity and linear regression and model selection based on Akaike's information criterion to investigate landscape controls on genetic diversity. Genetic differentiation between islands was best predicted with circuit‐theory models that accounted for the large difference in resistance to dispersal between land and ocean. In contrast, straight‐line distances were unrelated to either resistance distances or genetic differentiation. Instead, connectivity was determined by island‐hopping routes that allow organisms to minimize the distance of difficult ocean passages. Island populations of C. inornatus retained varying degrees of genetic diversity (NA = 1.83 – 7.39), but it was greatest on islands closer to the mainland, in terms of resistance‐distance units. In contrast, genetic diversity was unrelated to island size. Our results highlight the potential for islands to contribute to both theoretical and applied conservation, provide strong evidence of the driving forces of population structure within undisturbed landscapes, and identify the islands most valuable for conservation based on their contributions to gene flow and genetic diversity.  相似文献   
77.
Seabirds are the most threatened group of marine animals; 29% of species are at some risk of extinction. Significant threats to seabirds occur on islands where they breed, but in many cases, effective island conservation can mitigate these threats. To guide island‐based seabird conservation actions, we identified all islands with extant or extirpated populations of the 98 globally threatened seabird species, as recognized on the International Union for Conservation of Nature Red List, and quantified the presence of threatening invasive species, protected areas, and human populations. We matched these results with island attributes to highlight feasible island conservation opportunities. We identified 1362 threatened breeding seabird populations on 968 islands. On 803 (83%) of these islands, we identified threatening invasive species (20%), incomplete protected area coverage (23%), or both (40%). Most islands with threatened seabirds are amenable to island‐wide conservation action because they are small (57% were <1 km2), uninhabited (74%), and occur in high‐ or middle‐income countries (96%). Collectively these attributes make islands with threatened seabirds a rare opportunity for effective conservation at scale. La Biogeografía de Aves Marinas Amenazadas Globalmente y las Oportunidades de Conservación en Islas  相似文献   
78.
The taxonomic uniqueness of island populations is often uncertain which hinders effective prioritization for conservation. The Christmas Island shrew (Crocidura attenuata trichura) is the only member of the highly speciose eutherian family Soricidae recorded from Australia. It is currently classified as a subspecies of the Asian gray or long‐tailed shrew (C. attenuata), although it was originally described as a subspecies of the southeast Asian white‐toothed shrew (C. fuliginosa). The Christmas Island shrew is currently listed as endangered and has not been recorded in the wild since 1984–1985, when 2 specimens were collected after an 80‐year absence. We aimed to obtain DNA sequence data for cytochrome b (cytb) from Christmas Island shrew museum specimens to determine their taxonomic affinities and to confirm the identity of the 1980s specimens. The Cytb sequences from 5, 1898 specimens and a 1985 specimen were identical. In addition, the Christmas Island shrew cytb sequence was divergent at the species level from all available Crocidura cytb sequences. Rather than a population of a widespread species, current evidence suggests the Christmas Island shrew is a critically endangered endemic species, C. trichura, and a high priority for conservation. As the decisions typically required to save declining species can be delayed or deferred if the taxonomic status of the population in question is uncertain, it is hoped that the history of the Christmas Island shrew will encourage the clarification of taxonomy to be seen as an important first step in initiating informed and effective conservation action.  相似文献   
79.
城市地表形态对热环境的影响——以上海市为例   总被引:1,自引:0,他引:1  
基于遥感与GIS技术,利用Landsat7-ETM+影像反演地表温度,用社会经济统计数据、土地利用现状数据和道路交通网络数据计算城市景观形态参数以表征地表特征,从行政区(县)、5km间距同心环带和局部区块3个水平上划分空间单元建立数据样本,分析城市地表形态对热环境空间分布格局的影响。结果表明:(1)景观混合度和景观分裂度对地表温度有恒定的负向影响,区块连通性与地表温度负相关;(2)景观分裂度对热环境的影响取决于地类属性:分裂度大的增温地类,地表增温效应弱;分裂度大的降温地类,地表降温效应强;(3)人口密度和经济密度可对地表温度产生恒定正向影响;(4)人口密度、建设用地比例和房屋建筑比例是分布在区(县)尺度、同心圆环尺度和典型区块尺度上影响地表热环境最显著的地表形态要素。  相似文献   
80.
详细综述了南沙岛礁环境下装备的腐蚀特点以及耐蚀高熵合金的研究进展,着重分析了合金化元素及热处理工艺对耐蚀高熵合金腐蚀性能的影响规律.最终,归纳了耐蚀高熵合金在岛礁装备中的潜在应用领域,为全面提升我国关键装备在南沙岛礁环境中的服役能力提供了理论指导.  相似文献   
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