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91.
清朝,闽台已经成为自然灾害的多发地区,常见的灾害有洪水、干旱、台风、地震与瘟疫等.对福建危害最大的是水灾,对台湾危害最大的则是风灾.两岸人民为抗击自然灾害而共同努力,清地方政府采取多项救灾措施如蠲免、赈粮、捐赀及赋予台湾官员独断财权以应付突发灾情等,并取得了一定成效.  相似文献   
92.
This study documents the event chronology and causes of land-use change in a deltaic region of the Philippines since the beginnings of aquaculture in the late nineteenth century. Satellite images and topographic maps spanning the period 1972–2013 were processed to map fishponds and the natural habitats over which they have encroached. Historical archives were consulted and interviews were conducted to understand the historical exploitation of local natural resources and the reasons behind the recorded land changes. Results showed that aquaculture developed in the late nineteenth century and expanded subsequently across the landscape under a succession of forcing factors. The global market, for example, played an early role but a number of land-use changes were also a direct response to changing environmental constraints and natural hazards. These cumulative events have promoted continuous gain in favor of aquaculture, to the detriment of other land-use options.  相似文献   
93.
ABSTRACT

Small and medium-sized enterprises (SMEs) have a substantial role in the economy and job creation, but they are a remarkable source of environmental impacts. SMEs often lack skills and resources to compile environmental impact assessments; Streamlined Life Cycle Analysis (LCA) can provide efficient tools for this. An application of streamlined LCA relying heavily on database data, LCA clinic, was developed and tested on 23 SMEs in Finland. The climate change impacts were mainly caused by the production of raw materials, electricity and heating, whereas packaging and transportation were not influential. A significant amount of emissions were indirect, i.e. caused by production of raw materials. Thus, decreasing emissions from raw material production or selecting raw materials with a smaller environmental load could be a more efficient way to decrease emissions than reducing direct emissions such as those from electricity use. Lack of data in the LCA-databases was considered a challenge. An access to regionally customised datasets is important for the implementation of LCA clinics. Company feedback indicated that LCA clinics were useful in climate-friendly product design and increased environmental awareness, but did not lead to immediate actions to reduce emissions because of inadequate investment capabilities. Company managers had limited possibilities to use the results in marketing as comparative assessments would require a full LCA. Many company managers were willing to pay a fee sufficient to cover the costs of an LCA clinic, but some considered that the costs should be covered by external funding sources.  相似文献   
94.
饮用水中的消毒副产物及其控制策略   总被引:1,自引:1,他引:0  
楚文海  肖融  丁顺克  张瑞华 《环境科学》2021,42(11):5059-5074
消毒副产物(disinfection by-products,DBPs)是在饮用水消毒时由消毒剂与有机或无机前体物反应生成的一类次生污染物,其由于具有致癌、致畸和致突变的三致特性在全球范围内广受关注.聚焦于饮用水中的DBPs,介绍了DBPs的主要分类和研究历程,汇总了多地饮用水中常见DBPs的浓度水平以及全球饮用水水质标准对DBP指标的管控要求.随后系统介绍了饮用水中DBPs的控制策略,包括源头控制、过程控制、末端控制以及协同控制这4大类,并对各类控制方法的优缺点进行了分析.评述了中国的DBPs研究的现有水平和未来趋势,并展望了未来有关DBPs控制方法的研究方向.一方面,在评价某种工艺或技术对DBPs的控制效果时需要考虑DBPs浓度和水质综合毒性的变化,另一方面,建议关注耦合源头、过程和末端控制技术的协同控制方法,兼顾从源头到龙头每个节点,实现对饮用水中各类DBPs的高效控制.  相似文献   
95.
Anil Baral 《Ecological modelling》2010,221(15):1807-1818
A commonly encountered challenge in emergy analysis is the lack of transformity data for many economic products and services. To overcome this challenge, emergy analysts approximate the emergy input from the economy via a single emergy/money ratio for the country and the monetary price of economic inputs. This amounts to assuming homogeneity in the entire economy, and can introduce serious uncertainties in the results. This paper proposes and demonstrates the use of a thermodynamically augmented economic input-output model of the US economy for obtaining sector-specific emergy to money ratios that can be used instead of a single ratio. These ratios at the economy scale are more accurate than a single economy-wide emergy/money ratio, and can be obtained quickly for hundreds of economic products and services. Comparing sector-specific emergy/money ratios with those from conventional emergy studies indicates that the input-output model can provide reasonable estimates of transformities at least as a stop-gap measure until more detailed analysis is completed. A hybrid approach to emergy analysis is introduced and compared with conventional emergy analysis using life cycles of corn ethanol and gasoline as examples. Emergy and transformity data from the hybrid approach are similar to those from conventional emergy analysis, indicating the usefulness of the proposed approach. In addition, this work proposes the metric of return on emergy investment for assessing product alternatives with the same utility such as transportation fuels. The proposed approach and data may be used easily via web-based software.  相似文献   
96.
Two simplified versions of a numerical life cycle model for diazotrophic cyanobacteria (of the order Nostocales) are developed and evaluated. Both consider two-life cycle stages, one growing, nitrogen-fixing stage and one stage that combines the resting, germinating and vegetative stages. The versions differ in the vertical resolution of the non-diazotrophic stage: version 1 collects the biomass in one layer at the bottom, version 2 considers sinking and rising of biomass explicitly. The results of the two versions are compared with a complex cyanobacteria life cycle model which describes four different life cycle stages each with two internal quotas for energy and nitrogen. The two simplified approaches show a good agreement with respect to the main characteristics of cyanobacteria dynamics (timing and duration of blooms, magnitude of nitrogen fixation, interannual variability). Our model study shows that both simplified approaches are suitable to be implemented into three-dimensional coastal or lake models.  相似文献   
97.
亚热带常绿阔叶林下分布着可塑性强的耐荫植物,其叶片应对外界干扰的防御对策至少有物理性防御和化学性防御两种,这两种防御代价在一定的昆虫取食压力下在理论上应该存在权衡.为检验这种权衡是否普遍存在,分别测定了重庆缙云山4个常绿物种——光叶山矾(Symplocos lancifolia)、四川山矾(S.setchuensis)、四川毛蕊茶(Camellialawii)和细枝柃(Eurya loquaiana)在林窗和林下两种对照光环境下个体叶片的光饱和下的净光合速率、叶面积干重和部分化学防御物质含量.结果表明,4个物种生活在林窗的个体单位叶面积干重、叶片氮含量和单位面积净光合速率通常高于林下的个体,但是单位质量和单位面积的总酚含量和C/N值却低于林下的个体.蛋白质和非结构性碳水化合物含量在不同生境中没有显著差异.因为不同物种叶片对光照条件的响应不同,不同参数的变化在两种生境间的差异并不完全一致.本研究结果在一定程度上暗示了物种在林窗和林下分别倾向于采取物理和化学性防御对策,并初步证实了两种防御强度之间存在权衡关系.图4参40  相似文献   
98.
通过对1996~2005年渤海湾近岸海域海水镉、汞、铅和石油烃浓度变化的分析,发现海水中镉浓度呈明显上升趋势,汞、铅和石油烃则无明显变化趋势.加速生命试验法模型(Accelerated Life Testing model)的研究显示,1996~2005年渤海湾近岸海域海水镉、汞和铅平均浓度均已超过其对渤海湾常见渔业资源生物的安全浓度.镉、汞、铅和石油烃对生物的长期致死率鱼类分别为4.5%、16.3%、0.0%和12.0%,甲壳类为0.4%、7.9%、0.3%和6.6%,双壳类为10.5%、0.2%、0.2%和2.3%.效应加和模型(Independence Action model)的估算表明,在镉、汞、铅和石油烃组成的复合污染条件下,渤海湾常见鱼类、甲壳类和双壳类的长期死亡率分别为29.7%、14.6%和12.9%,其种群增长率分别降低约6.4%、14.6%和12.9%.与镉、汞、铅和石油烃单种污染物暴露相比,其复合污染导致的渤海湾常见渔业资源生物种群(鱼类、甲壳类和双壳类)增长率的降低更明显.因此,复合污染是导致渤海湾渔业资源衰退的重要因素。  相似文献   
99.
This study presents the contributions of materials, earth engineering machines and construction techniques to potential environmental impacts from the main items of typical road earthworks. To achieve this goal, the overall activity at a 1.9-km long French earthworks project site for a heavily trafficked highway was surveyed during its 2007–2009 construction period. Using data collected and a numerical model of road life cycle assessment (LCA), i.e. ECORCE, six indicators could be evaluated, namely: energy consumption, global warming potential, acidification, eutrophication, photochemical ozone creation, and human chronic toxicity. When available, several life cycle inventories were implemented in order to appraise indicator sensitivity with respect to the considered panel of pollutants. Results also allowed estimating from an LCA point of view: (i) the conservation of both aggregates and soil as induced by quicklime treatment and (ii) the duration necessary for projected traffic levels to offset the potential environmental impacts of the earthworks stage.  相似文献   
100.
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