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61.
环境工程地质质量综合评价是一个复杂的系统工程。影响质量评价的因素众多而又十分复杂,且各因素的影响程度也不相同,质量优劣的分级界线亦是模糊的。本文仅就采用多级模糊综合评判的方法,考虑多个因素的综合作用,对环境工程地质质量进行评价的基本思想途径与步骤方法,作一初步论述。此方法清晰、易用,能使更多影响质量评价的因素真实参与评判。这是一条环境工程地质质量评价由定性走向定量的有效途径,值得探索。 相似文献
62.
Samuel Nunn 《Geographical review》2007,97(1):89-111
ABSTRACT. The geography of terrorism remains underexplored. By focusing on the spatial patterns of terrorist attacks, the settings and land uses in which attacks occur, and the methods used to perpetrate violence, this analysis helps build a theory of terrorism geography. Between 1 January 1997 and 11 September 2005, 178 terrorist incidents occurred in the United States. Analysis of these incidents suggests three insights. At the national scale, terrorism in the United States clustered in large urban areas, with regional differentiation of terrorist motives and targets. At the scale of individual attack sites, terrorist motivations pinpointed offices, clinics, and public spaces; right‐wing violence, military, government, and infrastructural targets; and religious terrorism, commercial and special land uses. At the scale of individual interactions, terrorists crossed paths with victims in various ways. For example, the 2001 anthrax‐attack letters and lone‐wolf terrorism created alternative intersections of perpetrators with victims. 相似文献
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The Sarcheshmeh copper deposit is one of the world's largest Oligo-Miocene porphyry copper deposits in a continental arc setting with a well developed supergene sulfide zone, covered mainly by a hematitic gossan. Supergene oxidation and leaching, have developed a chalcocite enrichment blanket averaging 1.99% Cu, more than twice that of hypogene zone (0.89% Cu). The mature gossans overlying the Sarcheshmeh porphyry copper ores contain abundant hematite with variable amounts of goethite and jarosite, whereas immature gossans consist of iron-oxides, malachite, azurite and chrysocolla. In mature gossans, Au, Mo and Ag give significant anomalies much higher than the background concentrations. However, Cu has been leached in mature gossans and gives values close or even less than the normal or crustal content (< 36.7 ppm). Immature gossans are enriched in Cu (160.3 ppm), Zn (826.7 ppm), and Pb (88.6 ppm). Jarosite- and goethite-bearing gossans may have developed over the pyritic shell of most Iranian porphyry copper deposits with pyrite–chalcopyrite ratios greater than 10 and therefore, do not necessarily indicate a promising sulfide-enriched ore (Kader and Ijo). Hematite-bearing gossans overlying nonreactive alteration halos with pyrite–chalcopyrite ratios about 1.5 and quartz stringers have significant supergene sulfide ores (Sarcheshmeh and Miduk). The copper grade in supergene sulfide zone of Sarcheshmeh copper deposit ranges from 0.78% in propylitized rocks to 3.4% in sericitized volcanic rocks, corresponding to the increasing chalcopyrite–pyrite or chalcocite–pyrite ratios from 0.3 to 3, respectively. Immature gossans with dominant malachite and chrysocolla associated with jarosite and goethite give the most weakly developed enrichment zone, as at God-e-Kolvari. The average anomalous values of Au (59.6 ppb), Mo (42.5 ppm) and Ag (2.6 ppm) in mature gossans associated with the Sarcheshmeh copper mine may be a criterion that provides a significant exploration target for regional metallogenic blind porphyry ore districts in central Iranian volcano–plutonic continental arc settings. Drilling for new porphyry ores should be targeted where hematitic gossans are well developed. The ongoing gossan formation may result in natural acidic rock drainage (ARD). 相似文献
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主要发达国家提交UNFCCC的1990-2006年排放清单数据显示,部分发达国家已采取了确实的减排措施完成《京都议定书》规定的温室气体减排目标,其中,德、英、法、荷和瑞典是履行《京都议定书》温室气体目标效果最好的国家,分析各国所采取的减排政策/措施发现,这些国家完成《京都议定书》目标的实际路径大多是“避重就轻”的,其做法对于我国处于工业化中期的地区,采取非关键领域减排的策略可以为我国经济高速重化工发展腾出一定的排放空间,减少温室气体减排对经济发展的制约。 相似文献
67.
Brigitte Wolkinger Andrea Damm Stefan Schleicher Andreas Tuerk Wolf Grossman 《Climate Policy》2013,13(6):667-689
Having agreed upon a binding emissions reduction path by 2020, the EU plays a leading role in international climate policy. The EU currently pursues a dual approach through an Emissions Trading Scheme (ETS) at the EU level and also via national targets in sectors not covered by the ETS. The latter include the buildings sector, transportation, agriculture, and waste. Emissions from these sectors are mainly subject to policies at provincial and local levels. A method is presented for elaborating and implementing a long-term climate policy process up to 2030 for the regional (provincial) level. Building on regional GHG inventory data, a set of indicators for each sector is developed in order to arrive at a target path consistent with the deduced regional GHG reduction requirement. Policy measures and their implementation are then settled subsequent to this process. Quantitative regional targets are found to be a prerequisite for the formation of regional climate policy as they increase participant responsibility and commitment. A five-step process of stakeholder participation ensures effective implementation of regional climate action plans. Insights from an exemplary European region are drawn upon, and policy issues are discussed in both quantitative and institutional terms. 相似文献
68.
International negotiations under the UN Framework Convention on Climate Change could take several different approaches to advance future mitigation commitments. Options range from trying to reach consensus on specific long-term atmospheric concentration targets (e.g. 550 ppmv) to simply ignoring this contentious issue and focusing instead on what can be done in the nearer term. This paper argues for a strategy that lies between these two extremes. Internationally agreed threshold levels for certain categories of impacts or of risks posed by climate change could be translated into acceptable levels of atmospheric concentrations. This could help to establish a range of upper limits for global emissions in the medium term that could set the ambition level for negotiations on expanded GHG mitigation commitments. The paper thus considers how physical and socio-economic indicators of climate change impacts might be used to guide the setting of such targets. In an effort to explore the feasibility and implications of low levels of stabilisation, it also quantifies an intermediate global emission target for 2020 that keeps open the option to stabilise at 450 ppmv CO2 If new efforts to reduce emissions are not forthcoming (e.g. the Kyoto Protocol or similar mitigation efforts fail), there is a significant chance that the option of 450 ppmv CO2 is out of reach as of 2020. Regardless of the preferred approach to shaping new international commitments on climate change, progress will require improved information on the avoided impacts climate change at different levels of mitigation and careful assessment of mitigation costs. 相似文献
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贵州镇远地区钾镁煌斑岩产出控制因素浅析 总被引:6,自引:0,他引:6
贵州镇远马坪钾镁煌斑岩为我国发现的第一个含原生金刚石的钾镁煌斑岩,其时代为加里东中期。根据区内当时沉积建造的特点,结合钾镁煌斑岩常包含早期捕虏体的情况,尤其是区内钾镁煌斑岩主要产于加里东期北东向背斜构造翼部拐点范围的事实,认为区内钾镁煌斑岩的侵位应发生在加里东期沉积建造结束褶皱构造开始时刻。加里东构造运动先是沉积建造的塑性变形褶皱造山,岩层能干化后才开始发育大量断裂构造。纵弯褶皱在挤压作用背景下,因褶皱拐点存在拉伸和剪切的应力而构成透入性构造软弱部位,被深部岩浆热力所突破而成为上涌侵位及喷发通道。区域上,四堡期东西向基底断裂构造控制区内钾镁煌斑岩东西向带状分布,而加里东期褶皱及其拐点控制钾镁煌斑岩体(群)的产出,因此金刚石的找矿勘查应主要在有金刚石找矿信息的褶皱构造拐点范围开展。 相似文献