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鸭河口水库流域高炮人工增雨试验效果评价 总被引:1,自引:0,他引:1
1998,1999年夏季在鸭河口水库流域进行了高炮人工增雨作业试验,结果表明,借助雷达引导,选择适当作业时机,高炮增雨作用一般可增雨20%-40%。 相似文献
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In recent years, an increasing number of local governments are recognizing the impact of climate change on different urban sectors. This has led many to pursue climate adaptation planning, seeking to achieve preparedness through reducing vulnerability and enhancing resilience of populations, assets, and municipal operations. Although cities typically share these common goals, many are electing to pursue different planning approaches. In this paper, we examine three climate adaptation planning approaches in the cities of Quito (Ecuador), Surat (India), and Durban (South Africa) and analyze the trade-offs associated with different planning pathways and different forms of stakeholder involvement. We assess the potentials and limitations of these different approaches, including their implications for enhancing government integration and coordination, promoting participation and adaptive capacity of vulnerable groups, and facilitating overall urban resilience. We find that, in order to gain widespread commitment on adaptation, sustained political leadership from the top, departmental engagement, and continued involvement from a variety of stakeholders are integral to effective decision-making and institutionalization of programs in the long run. When climate adaptation is advanced with a focus on learning, awareness, and capacity building, the process will likely lead to more sustained, legitimate, and comprehensive adaptation plans and policies that enhance the resilience of the most affected urban areas and residents. 相似文献
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Helena Valve 《Geoforum》2011,42(2):222-230
Identification of GM plants with their internal molecular-genetic qualities serves transformation of living organisms into identifiable commodities and objects of regulation. From molecular reductionist assumptions it also follows that scientific research is to be based on experiments that allow analysis of genetic influence in isolation. In this paper, I analyse molecular reductionism ‘in action’ by means of an ethnographic case study, focusing on the practices and transformations through which a field trial of transgenic trees created understanding of the risks or risklessness of the trees. The results show how the mobilisation of the field trial design, choosing of key analytical scales and formation of the research team stabilised the paths that experimentation was to follow. The scientists took the emerging inconsistencies and surprises calmly, indicating that unexpected events are an essential part of a scientific process. However, surprises could matter only in relation to the testing arrangements. Therefore, what could become visible and what could make a difference for the constitution of risk/risklessness were the fluctuations that the particular analytical assemblages defined as significant from the outset. Meanwhile, it was impossible to treat the trees and the field ecosystem as mutually constitutive. Nevertheless, there is no reason to think of knowledge production concerning transgenic organisms in deterministic terms. First, scientists are bound to be complexly engaged with the ecosystems that they are supposed to sort out. Second, consideration of the public lessons of experiments may elicit problems and limitations of molecular reductionism. 相似文献
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Sedimentologists recognize that development of a fine‐resolution, truly three‐dimensional analytical tool is essential if the internal structure of an opaque material is to be examined. This paper therefore seeks to: (i) test the viability of magnetic resonance imaging for sedimentological research; and (ii) investigate fine‐sediment infiltration into gravel beds. The results of six experiments are analysed quantitatively using Image J post‐processing software. Data indicate that magnetic resonance imaging‐based measurements of particle axes and volumes are comparable with standard laboratory techniques. Furthermore, the technique permits visualization and analysis of differences in the pattern of fine‐sediment infiltration (median particle diameter, d) into a framework of gravel (median particle diameter, D). Data clearly illustrate a siltation process for samples of D/d = 34 and a sealing process for samples of D/d = 7 where the seal is restricted to a depth equal to 2D. This pore‐scale visualization is valuable to the understanding of hydraulic–sediment–habitat interactions. 相似文献
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Recent attempts to conduct experiments in climate ‘geoengineering’ have demonstrated the deeply controversial nature of this field of scientific research. Social scientists have begun to explore public perceptions of geoengineering, and have documented a significant degree of concern over the effective governance of research and experimentation in this area. Yet, public perception on what constitutes a legitimate geoengineering experiment and how it should be governed remains under-researched. In this article we report on a series of experimental deliberative workshops with members of the public designed to elicit and explicate diverse understandings of geoengineering experiments and their governance. In contrast to previous methods of invited public deliberation, which privilege egalitarian-consensual models of discourse and decision-making, we test a novel approach that places majoritarian, individualistic, and consensual forms of public deliberation on an equal footing. Our study suggests that the perceived controllability of experimental interventions is central to public views on their acceptability, but that controllability is itself a complex, multifaceted quality, drawing together a set of heterogeneous concerns about the purpose and repercussions of scientific work. The citizens who participated in our workshops employed four criteria to adjudicate the acceptability of geoengineering experiments: (1) the degree of containment; (2) the uncertainty surrounding experimental outcomes; (3) the reversibility of impacts; and (4) the scientific purity of the enterprise. We theorize that the public legitimacy of geoengineering experiments depends on variable, context-specific combinations of these criteria, and that technical determinations of the proper ‘scale’ or ‘location’ for geoengineering research will be poor predictors of the sorts of public concerns that will be triggered by further experimentation in this area. 相似文献
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我国地理信息系统建设及进展(1) 总被引:3,自引:0,他引:3
GIS的基础背景和发展阶段与GIS业务化应用系统的建设两个部分,着重叙述了GIS建设的探索过程和发展思路,指出GIS建设从初步发展时期的研究实验、局部应用向着实用化、集成化和产业化方向发展,成为国民经济和社会发展普遍使用的工具,在各行各业发挥着重要的作用。同时用实例说明GIS业务化应用系统,在我国大体经历的四个发展阶段。 相似文献
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To further our knowledge of the coupling between the hydraulic and mechanical behaviours of the swelling soils, this paper presents an experimental study on a bentonite/silt mixture using an osmotic odometer. A loading/unloading cycle was applied to samples with different initial dry densities (1.27, 1.48, and 1.55 Mg m− 3) at different constant suctions (0, 2, and 8 MPa). We noted that the initial state of the soils after compaction significantly influenced the values of the apparent preconsolidation stress p0(s), the virgin compression index λ(s), and the elastic compression index κ.These experimental results provided a sufficient database to interpret the mechanical behaviour of the swelling soil and define three yielding surfaces:
- – the suction limit between micro- and macrostructure (sm/M) and the suction limit between nano- and microstructure (sn/m), which depend completely on the soil fabrics and the diameter separating the nano-, micro-, and macrostructure,
- – the Loading Collapse (LC) curve, representing the preconsolidation stress variation as a function of suction,
- – the Saturation Curve (SC), representing the variation of the saturation stress (Psat) as a function of suction.
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Pinnaduwa H. S. W. Kulatilake Jeong-Gi Um 《Geotechnical and Geological Engineering》2003,21(2):149-165
The cone tip resistance data available for the clay site at Texas A&M University, USA (one of the National Geotechnical Experimentation Sites) are used to show how the spatial variation of a soil property can be quantified. It is suggested that the first step in quantifying the spatial variation of a soil property should be the identification or selection of the statistically homogeneous soil layers. A new simple procedure is suggested to identify statistically homogeneous layers in a soil profile. Through examples it is shown that the procedure works extremely well in identifying the statistically homogeneous layers. For the chosen statistically homogeneous layers, the spatial variation of cone tip resistance with depth is quantified in terms of a constant mean or a mean trend, variance/standard deviation/coefficient of variation or a variance around the mean trend, and a correlation or variogram function. Correlation distances in the depth direction were found to be between 0.1 and 0.5m for the two soil layers investigated. It was shown that the correlation distance decreases in the presence of a global mean trend for the soil property. In such cases, it is important to note that a part of the correlation is automatically included in the mean trend function. 相似文献
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