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161.
The Road to Rio+20 is the journey of countries in the world pursuing the sustainable development.As the first country to release the national Agenda 21,China’s experience and lessons are of great significance for both China itself and other countries.The paper reviews the progress made and problems remained in pursuing the sustainable development in China with regard to policy formulation,institutional arrangements,planning and management.In the past five years,the mandatory targets-driven approach,which focused on energy efficiency and key pollutants reduction,played a very important role and made China comprehensive outcomes for sustainability.In order to achieve the targets,China adopted an integrated policy package including legal,administrative,economic and technology instruments.During the 12th Five-Year Plan period(2011-2015),China will continue and strengthen the approach above and mainstream the transformation of economic development pattern through realizing the idea of green and low-carbon development.By summarizing policy trends in the world,the paper points out two directions,i.e.,integration approach and taking prioritized and concrete actions for a sustainable future beyond 2012.The paper also presents policy approaches and recommendations for sustainable development in the next 10 years in China.  相似文献   
162.
This study utilises the equivalent granular state parameter, ψ, as a key parameter for studying static and cyclic instability and their linkage. ψ can be considered as a generalisation of the state parameter as first proposed by Been and Jefferies so that the influence of fines content in addition to stress and density state can be captured. Test results presented in this study conclusively showed that ψ at the start of undrained shearing and ηIS, the stress ratio at onset of static instability, can be described by a single relationship irrespective of fines content for both compression and extension shearing. This single relationship is referred as instability curve. However, the instability curve in extension shearing is different from that of compression. In this paper, the capacity of the instability curve in predicting triggering of cyclic instability was evaluated experimentally. An extensive series of undrained one-way (compression) and non-symmetric two-way cyclic triaxial tests, in addition to monotonic triaxial tests in both compression and extension were conducted for this evaluation. Furthermore, a published database for Hokksund sand with fines was also used. Test results show that cyclic instability was triggered shortly after the cyclic effective stress path crossed the estimated ηIS-zone(s) as obtained from instability curve(s) irrespective of whether instability occurs in the compression or extension side.  相似文献   
163.
Numerous morphological changes can occur where two channels of distinct sediment and flow regimes meet, including abrupt shifts in channel slope, cross‐sectional area, planform style, and bed sediment size along the receiving channel. Along the Rio Chama between El Vado and Abiquiu Dams, northern New Mexico, arroyo tributaries intermittently deliver sediment from erodible sandstone and shale canyon walls to the mainstem channel. Much of the tributary activity occurs in flash floods and debris flows during summer thunderstorms, which often load the channel with sand and deposit coarser material at the mainstem confluence. In contrast, mainstem channel flow is dominated by snowmelt runoff. To examine tributary controls, we systematically collected cross‐section elevation and bed sediment data upstream and downstream of 26 tributary confluences along a 17 km reach. Data from 203 cross‐sections were used to build a one‐dimensional hydraulic model for comparing estimated channel parameters at bankfull and low‐flow conditions at these sites As compared to intermediate reaches, confluences primarily impact gradient and bed sediment size, reducing both parameters upstream of confluences and increasing them downstream. Cross‐section area is also slightly elevated above tributary confluences and reduced below. Major shifts in slope and bed sediment size at confluences appear to drive variations in sediment entrainment and transport capacity and the relative storage of sand along the channel bed. The data were analyzed and compared to models of channel organization based on lateral inputs, such as the Network Variance Model and the Sediment Link Concept. At a larger scale, hillslope ? channel coupling increases in the downstream third of the study reach, where the canyon narrows, resulting in steeper slopes and more continuous coarse bed material along the mainstem, and thus, limiting the contrast with tributary confluences. However, channel form and sediment characteristics are highly variable along the study reach, reflecting variations in the size and volume of sediment inputs related to the surface geology in tributary watersheds, morphology of the Rio Chama at the junction (i.e. bends, confinement), and the relative magnitude and location of past depositional events. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
164.
深水水道沉积构型及其演化一直是沉积学界研究的热点。基于Rio Muni盆地深水区470 km2高分辨率三维地震数据,在精细地震解释的基础上,对研究区发育的深水水道的沉积构型、演化进行探讨。主要取得4点认识:(1)深水水道的弯曲度主要受控于物源供给和海底坡度,研究区发育弯曲水道、顺直水道2类深水水道;(2)起源于陆架边缘的深水水道,物源供给相对充分,弯曲度高,其剖面往往不对称,水道壁发育滑塌或阶地,垂向演化具有侧向迁移特征,发育废弃水道;(3)而起源于中上陆坡的深水水道,其弯曲度低,剖面具有U形特征,水道壁光滑无滑塌或阶地, 主要以垂向加积为主。由于物源供给不足,顺直水道逐渐被深海泥质披覆沉积充填;(4)同一条深水水道,由上陆坡向下陆坡,随着海底坡度的降低,其弯曲度呈增大趋势。  相似文献   
165.
Mechanisms of democratic participation have been activated in Colombia since 2006 for the purpose of protecting water sources, hydrosocial territories and peasant livelihoods. A chronological perspective on the numerous and varied cases illustrates their cumulative, transformative effect on judicial decisions taken by the high courts, which have endorsed these mechanisms of direct democracy and expanded the scope of democratization to socioenvironmental issues. The process of environmental democratization in Colombia has been gradual, starting with the creation of opportunities for citizen participation in the Constitution of 1991; followed in the first decade of this century by the activation of the mechanisms of democratic participation created; and culminating with the watershed Constitutional Court ruling T-445 of 2016, which confirmed the right of municipalities to consult with their citizens about mining and oil extraction in their territories. The cases are analyzed here through the lens of democratization and transformative and judicialized politics. The paper argues that the reconfiguration of power through the use and contestation of participatory mechanisms reveals an ambiguous state-formation process characterized by repressed democratization. It also demonstrates that the process of environmental democratization that started with the activation of the democratic participation mechanisms introduced in the Constitution of 1991 has been one of transformative democratic politics, in which a dynamic array of political actors have consolidated democratic participation on environmental issues through constitutional lobbying and activism.  相似文献   
166.
Voluntary associations are at the heart of Swedish rural policy and strategies for governance as partners in bringing about ‘development from below.’ Examining the implications of this new responsibility being placed on the civil society in new modes of multilevel governance, I ask: do these changes presage greater political space for individuals vis à vis the state or is Swedish rural policy premised on ideas about an institutional context that might be disappearing? In comparative research in rural Sweden, I discuss state and civil-society relations at the macro level in light of the gendered micro-politics of associational life on the ground. Through ethnographic research with people involved in development work of different kinds, I examine how ideas about community associations are used to mobilize rural policy. I analyze its’ political implications and argue for the importance of analyzing macro in relation to the micropolitics on the ground for a better theoretical understanding of democracy and power in rural governance, in particular its gendered implications. I argue that past collaborative relations between the civil society and the state’s administrative apparatuses as well as the current focus of rural policy have enabled the state to hand over service functions to the civil society and diluted their ‘voice,’ incongrously endangering the institutional basis of rural policy itself. Further, attention to the gendered micropolitics of associational life makes apparent cleavages within civil society and its underlying relations of gender and power that challenge current conceptualizations on the neoliberalization of rural policy.  相似文献   
167.
This paper examines the spatial dynamics of urbanism in Rio de Janeiro during the early nineteenth century. Conventional narratives of modernisation fail to capture the complexities of this moment, between 1808 and 1821, when the city replaced Lisbon as the capital of the Portuguese empire. The position of colony and metropolis were inverted, Portuguese absolutism was bolstered by British liberalism, and a market-economy arose alongside the expansion of slavery. As the newly-created imperial capital, Rio felt the effects of these various transformations: the physical boundaries of the city rapidly expanded, its economy diversified and the cultural life of the city was re-shaped. Our aim in this paper is to understand this particular moment of urban transformation as a product of the intersection of global networks of trade, slavery and industrial capitalism. Rather than depicting the historical geography of the city as a passive space for European conquest and expansion, we consider the extent to which its urban dynamics were shaped by a distinct local geography of globalisation. In particular, we examine the interrelated spatialities that are part and parcel of the modernising process.  相似文献   
168.
This study examines spatial variations in natural levee deposits within the lower reaches of a large coastal plain drainage system. The Pánuco basin (98,227 km2) drains east-central Mexico, and is an excellent setting to examine the influence of watershed and local controls on the morphology and sedimentology of natural levees. Although many fluvial systems in the U.S. Gulf Coastal Plain have been investigated, the rivers in the Mexican Gulf Coastal Plain have received comparatively little attention. Lateral and downstream characteristics of natural levee morphology and sediment texture are considered within the context of meandering river floodplain deposits. Data sources include total-stations surveying, sediment samples of surficial levee deposits, topographic maps (1:50,000), and aerial photographs (1:40,000). The slope of natural levees average 0.0049 m/m, whereas the texture (D84) of levee deposits averages 0.12 mm. Natural levee characteristics vary due to local- and watershed-scale controls. The lateral reduction in levee height displays a curvilinear pattern that coincides with an abrupt change in sediment texture. The downstream pattern of natural levee texture exhibits the influence of local-scale perturbations superimposed upon a larger watershed-scale trend. Disruption to the fining trend, either by tributary inputs of sediment or reworking of Tertiary valley deposits, is retained for a limited distance. The influence of the channel planform geometry on levee morphology is examined by consideration of the radius of curvature (Rc) of meander bends, and is inversely related to natural levee width. This suggests that the planform geometry of river channels exerts a control on the dispersal of flood sediments, and is responsible for considerable local variability in the floodplain topography. The average width of natural levees increases with drainage area, from an average of 747 m in the Moctezuma to an average of 894 m in the Pánuco. However, in the lower reaches of the Pánuco valley the width of natural levees rapidly decreases, which is associated with fining of the suspended sediment load. Thus, the reduction in natural levee width signifies an abrupt change in the directionality of cause–effect relationships at the watershed-scale. Findings from this study elucidate linkages between meandering river channels and floodplains for a large lowland alluvial valley.  相似文献   
169.
天然金刚石结构中氢的赋存状态   总被引:4,自引:0,他引:4  
利用振动光谱(IR、RAMAM)研究金刚石结构中的含氢物相,发现金刚石结构中存在晶格氢和间隙氢两种。其中HF的存在为首次提出。同时不同的含氢物相在金刚石结构中的赋存状态不尽相同。  相似文献   
170.
This paper presents the multiaxial formulation of a plasticity model for sand under cyclic shearing. The model adopts a kinematic hardening circular cone as the yield surface and three non-circular conical surfaces corresponding to the deviatoric stress ratios at phase transformation, peak strength and critical state. The shape of the non-circular surfaces is formulated in accordance with the experimentally established failure criteria, while their size is related to the value of the state parameter ψ. To simulate cyclic response under small and large shear strain amplitudes without a change in model parameters, it was found necessary to introduce: (a) a non-linear hysteretic (Ramberg–Osgood type) formulation for the strain rate of elastic states and (b) an empirical index of the effect of fabric evolution during shearing which scales the plastic modulus. This index is estimated in terms of a macroscopic second-order fabric tensor, which develops as a function of the plastic volumetric strain increment and the loading direction in the deviatoric plane. Comparison of simulations to pertinent data from 27 resonant column, cyclic triaxial and cyclic direct simple shear tests provide a measure for the overall accuracy of the model.  相似文献   
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