排序方式: 共有41条查询结果,搜索用时 31 毫秒
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采用Fourier-Bessel波函数展开法,给出了半空间中地下夹塞物对平面SV波的散射解析解。借助大圆弧面近似模拟水平地表,由连续性边界条件和自由地表条件建立方程求解。通过参数分析,讨论了夹塞物本身及入射波特性对地表位移的影响规律。研究表明:夹塞物附近地表位移放大效应显著,地表位移对入射SV波频率和角度的变化比较敏感。当埋深较深时,夹塞物的散射效应可以忽略。 相似文献
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Randolph Haluza-DeLay 《Local Environment》2013,18(7):727-745
Some scholars and activists have suggested that discourses of environmental sustainability do not include sufficient attention to social issues or environmental justice. Since social inclusion is a prevalent masterframe among activists and in social policy circles in Canada and elsewhere, our research explored the extent that English-speaking Canadian environmental non-governmental organisations (ENGOs) incorporate discursive aspects of social inclusion into their website communication. Social inclusion includes such issues as multiculturalism, gender inequality, low income and racialisation. We analysed mission statements, programmes and policy analysis presented by a sample of ENGOs drawn from the membership of the Canadian Environmental Network for evidence of a variety of indicators of attention to social inclusion. We conclude that environmental groups remain locked into an “environmentalist” frame that often ignores such issues. This has major implications for partnerships with other Canadian social movements. 相似文献
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Trotta F Cravotto G Casile G 《Environmental science and pollution research international》2003,10(3):144-146
Chiral, atropisomeric 2,2'-dihydroxy-1,1'-binaphthyl has been extensively used to direct asymmetric processes. Its key role in asymmetric catalysis has spurred efforts to synthesize it in the optically pure form, but the reported synthetic routes have a significant environmental impact. In an aqueous peroxydase-cyclodextrin system the oxidative coupling of 2-naphthol took place very rapidly in almost quantitative yield and resulted in an enantiomeric excess. This one-pot synthesis do not require any organic solvents and oxidising metal cations. 相似文献
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在工程建设中,工地及邻近地区的断层活动性是工程设计的一项重要依据。在总结以往研究的基础上,介绍了显微构造分析法和包裹体方法在断层活动性评价中的国内外最新研究成果。事实表明,这两种方法在工程地质领域具有良好的应用前景。 相似文献
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E. Manuela Garrido Marcos Santos Paulo Silva Fernando Cagide Jorge Garrido Fernanda Borges 《Journal of environmental science and health. Part. B》2013,48(9):869-875
The chlorophenoxy herbicide MCPA (4-chloro-2-methylphenoxyacetic acid), widely used for the control of broad-leaf weeds primarily in cereal and grass seed crops, still remains one of the most often used herbicides in Portugal. As the formation of inclusion complexes with cyclodextrins can improve its solubility properties, the interaction between the herbicide MCPA and β-cyclodextrin was investigated. The stability constants describing the extent of formation of the complexes have been determined by phase-solubility studies. Different analytical techniques [ultraviolet-visible spectroscopy (UV-Vis), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR)] were employed for a thorough investigation of the structural characteristics of the obtained complexes, which exhibited distinct features and properties from both “guest” and “host” molecules. FTIR and 1H NMR data obtained for the MCPA/β-CD complexes gave information about the interaction between MCPA and the nonpolar cyclodextrin cavity. The dramatic change observed in band frequency and proton displacements of OCH2 group and H6 aromatic proton confirmed the inclusion of MCPA in β-CD. The formation of an inclusion complex between MCPA and β-CD increased the aqueous solubility of this herbicide which could be a particularly advantageous property for some specific applications, namely to improve commercial formulation and for environmental protection. 相似文献
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Local Environment has established a bit of a niche in local sustainability indicator studies. In 1997 it published the important debate between Jeb Brugman and Graham Pinfield, which highlighted that sustainability indicators and their role are contested issues (Vol. 2, Nos 1-3). In 1999 it produce a first special issue on the topic (Vol. 4, No. 2). As the editors identified, this special issue probed ‘deeper into aspects of indicator selection, methodology, theory and practice’. The papers presented there began to discuss a theme that is developed further in this special issue, that of the relationship between the objective and the subjective in indicator development and use. Our special issue brings together three full papers and a commentary presenting research and information from the USA, Sweden, France and Austria. In this editorial we are going to review the growth of interest in sustainability indicators and the changing way in which they are viewed and briefly comment on some recent indicator projects that we have been involved in. 相似文献
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Jutta Gutberlet Crystal Tremblay Emma Taylor Nandakumar Divakarannair 《Local Environment》2013,18(8):733-747
What is considered garbage embodies a recoverable economic value, and environmental cost if not recycled. Throughout the world, the often marginalised and impoverished population earns a living through informal recycling. This is also true for Victoria, British Columbia, one of the most affluent cities in Canada. This paper discusses results of a participatory socio-economic survey involving informal recyclers in Victoria, BC to determine their livelihood determinants. The findings reveal that “binning” is an important survival strategy to generate income. A new waste-management model that considers the social and environmental context is needed. Inclusive public policies can respond to the livelihood concerns outlined in this paper by facilitating access to recyclable materials, devising occupational safety improvements and educating about alternative strategies for resource recovery. This model can contribute to the overall sustainability of the community by reducing the waste of resources and people, empowering marginalised populations and reducing the environmental impacts of natural resource use and waste disposal. 相似文献
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目的 研究吊耳在岛礁环境下的腐蚀特征及其对疲劳性能的影响。方法 通过开展吊耳试验件的岛礁自然环境试验,测试其不同在试验周期的疲劳性能,分析断口形貌、元素含量变化,研究腐蚀对吊耳抗疲劳性能的影响。结果 在1 a的岛礁自然环境试验中,吊耳的腐蚀部位主要为表面镀层,并且呈非均匀腐蚀特征。随着试验时间的延长,吊耳平均疲劳断裂循环次数呈下降趋势,疲劳断口的韧性断裂特征减弱,并且氢含量有所增加。吊耳内部存在MnS夹杂物,位于韧窝底部。结论 吊耳表面点蚀坑、内部MnS夹杂物对疲劳载荷作用下裂纹的萌生和生长起到促进作用,降低了其抗疲劳性能,应加强腐蚀防护和质量控制。 相似文献
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为提高臭氧的稳定性,采用臭氧化Hp-β-环糊精溶液的方法对臭氧进行包络。考察了臭氧/Hp-β-环糊精包络物的氧化特性,臭氧化量和Hp-β-环糊精浓度对臭氧/Hp-β-环糊精包络物氧化能力的影响,并研究了臭氧/Hp-β-环糊精包络物对二级出水中添加的10种药品和个人护理用品(PPCPs)的去除效果。结果表明:臭氧/Hp-β-环糊精包络物具有持续的氧化能力,增加臭氧化量或Hp-β-环糊精浓度可显著提升臭氧/Hp-β-环糊精包络物的氧化能力。臭氧/Hp-β-环糊精包络物有较强的氧化性;向0.7 g/L的Hp-β-环糊精溶液中通入6 mg臭氧后,PPCPs的去除率为50%~70%,去除率受PPCPs分子结构影响。臭氧/Hp-β-环糊精包络物氧化可与其他氧化技术联合应用于污染物去除或用作臭氧化后的持续氧化。 相似文献