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881.
基于改进的SFA模型对长江经济带108个城市2004—2016年的绿色创新效率与生态治理绩效值进行测度,借助耦合协调模型及探索性空间数据分析法对两系统的耦合协调度和时空分异特征进行分析,进而运用PVAR模型考察其响应关系。结果表明:①2004—2016年两系统整体处于初级协调阶段,未来仍有较大提升空间;空间上自东向西梯度递减,高协调区集中在东部城市;②两系统的耦合协调度具有空间正关联性,低-低集聚城市数多于高-高集聚,协调发展领先城市对周边城市的辐射带动作用较弱;③生态治理绩效对绿色创新效率响应较弱,而绿色创新效率对生态治理绩效响应则较强,且二者均对自身依赖较强,未来优化其互动机制应是长江经济带高质量发展的重点。  相似文献   
882.
自新型冠状病毒肺炎疫情肆虐以来,全球国际移民流动按下暂停键。我国也面临着同样的情况,部分城市内部聚集着因疫情难以回国的国际移民,这对于地方政府的移民管治提出了巨大挑战。通过结合运用地理学与人类学的跨学科视角,在福柯的权力与异端辩证关系框架的基础上,加入了“管治-响应”的逻辑思路进行重组,并采用该分析框架,以广西阳朔为例,讨论后疫情时代国际移民管治与个体生存策略。通过结合参与式观察法与网络民族志法,结果发现:首先,为避免疫情防控中政治尺度跃迁引发的国际舆论事件,地方政府在国际移民群体中寻找权力代理人,并与之形成权力联盟,对移民个体进行管治,包括“规训/照料”“医治/隔离”“监控/放任。这种转换将原本权力关系中的地方政府与移民个体之间的矛盾转化为权力代理人与移民个体之间的矛盾,有效地规避了尺度跃迁问题。其次,移民个体结合自身的社会资本,采用特有的响应策略,包括“权力代理人”“顺从/搭便车”“治疗/自我管治”“不合作/破坏”。这些发现有利于加深对国际移民社会融合的理解,为地方政府的移民管治提供新思路。  相似文献   
883.
主观幸福感是目前国内外研究热点,与提升居民生活质量和建设宜居城市密切相关。已有大部分文献侧重单一空间尺度的研究,分析社会经济属性和地理环境要素(包括建成环境、社会环境、环境污染)对主观幸福感的影响;也有部分研究关注居民日常出行属性和活动特征对主观幸福感的作用机制,探讨长期幸福感与短期幸福感的内在关系。论文对上述研究进行较为系统的梳理与评价,综合考虑地理环境、时空行为与主观幸福感的复杂关系,构建主观幸福感的理论研究框架,总结时空行为视角下多尺度、多维度地理环境要素对主观幸福感的影响机制以及作用路径,并探讨主观幸福感的时空动态规律以及微观行为机制,为改善城市人居环境、优化居民行为模式提供科学依据和政策建议。  相似文献   
884.
相对辐射定标是获得各类光学遥感卫星传感器的高精度观测产品的必备条件,由于受发射震动、在轨空间环境变化等因素以及传感器自身衰减的影响,传感器在轨响应状态会随时间发生衰减和漂移,单一相对辐射定标方法无法保障卫星传感器在特定时间的探元响应一致性。本文以光学卫星传感器全生命周期影像辐射质量保障为目标,主要研究了光学卫星传感器在轨生命周期内高频率、高定标精度的常态化相对辐射定标方法,并总结了当前常用的相对辐射定标精度评估方法,评估了各定标方法的指标以及应用场景。利用珞珈一号01星(LJ1-01)夜光传感器获取的影像进行在轨暗电流、和在轨均匀场地定标实验和验证,珠海一号02组高光谱卫星影像被用来实施和验证统计定标和偏航辐射定标方法,并耦合多种定标方法实现常态化辐射定标。实验结果表明:各种定标方法处理后影像的条纹系数小于0.25%,图像相对标准差均优于3.00%;多种定标方法相互结合的常态化辐射定标方法实现了多种定标方法的优势最大化,完成常见传感器的高精度在轨标定。  相似文献   
885.
鲁北平原因超量开采地下水而引发了诸多水环境问题.本文对其分布规律和演化趋势进行了分析,并提出了对策建议.  相似文献   
886.
The conventional piecemeal approach to environmental treaty-making has resulted in a ‘maze’ of international agreements. However, little is known empirically about its overall structure and evolutionary dynamics. This study reveals and characterizes the evolving structure of the web of international environmental treaty law. The structure was approximated using 1001 cross-references among 747 multilateral environmental agreements concluded from 1857 to 2012. Known network analysis measures were used to answer the following questions: has a complex system of international environmental treaty law emerged? If so when, and what does it look like? What are its topological properties? To what extent is the institutional complex fragmented? The network analysis suggested that multilateral environmental agreements have self-organized into an interlocking system with a complex network structure. Furthermore, the system has defragmented as it coevolved with the increasing complexity and interconnectivity of global environmental challenges. This study demonstrates the need to approach multilateral environmental agreements in the context of a complex networked system, and recommends against assuming the overall institutional structure is fragmented. Proposals for global environmental governance reform should pay attention to this network's emergent polycentric order and complexity and to the implications of these features for the functioning of the multilateral environmental agreement system.  相似文献   
887.
Severe hydrological droughts in the Amazon have generally been associated with strong El Niño events. More than 100 years of stage record at Manaus harbour confirms that minimum water levels generally coincide with intense warming in the tropical Pacific sea waters. During 2005, however, the Amazon experienced a severe drought which was not associated with an El Niño event. Unless what usually occurs during strong El Niño events, when negative rainfall anomalies usually affect central and eastern Amazon drainage basin; rainfall deficiencies in the drought of 2005 were spatially constrained to the west and southwest of the basin. In spite of this, discharge stations at the main‐stem recorded minimum water levels as low as those observed during the basin‐wide 1996–1997 El Niño‐related drought. The analysis of river discharges along the main‐stem and major tributaries during the drought of 2004–2005 revealed that the recession on major tributaries began almost simultaneously. This was not the case in the 1996–1997 drought, when above‐normal contribution of some tributaries for a short period during high water was crucial to partially counterbalance high discharge deficits of the other tributaries. Since time‐lagged contributions of major tributaries are fundamental to damp the extremes in the main‐stem, an almost coincident recession in almost all tributaries caused a rapid decrease in water discharges during the 2005 event. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
888.
Vegetation changes can significantly affect catchment water balance. It is important to evaluate the effects of vegetation cover change on streamflow as changes in streamflow relate to water security. This study focuses on the use of statistical methods to determine responses in streamflow at seven paired catchments in Australia, New Zealand, and South Africa to vegetation change. The non‐parametric Mann–Kendall test and Pettitt's test were used to identify trends and change points in the annual streamflow records. Statistically significant trends in annual streamflow were detected for most of the treated catchments. It took between 3 and 10 years for a change in vegetation cover to result in significant change in annual streamflow. Presence of the change points in streamflow was associated with changes in the mean, variance, and distribution of annual streamflow. The streamflow in the deforestation catchments increased after the change points, whereas reduction in streamflow was observed in the afforestation catchments. The streamflow response is mainly affected by the climate and underlying vegetation change. Daily flow duration curves (FDCs) for the whole period and pre‐change and post‐change point periods also were analysed to investigate the changes in flow regime. Three types of vegetation change effects on the flow regime have been identified. The relative reductions in most percentile flows are constant in the afforestation catchments. The comparison of trend, change point, and FDC in the annual streamflow from the paired experiments reflects the important role of the vegetation change. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
889.
Two formulations for calculating dynamic response of a cylindrical cavity in cross‐anisotropic porous media based on complex functions theory are presented. The basis of the method is the solution of Biot's consolidation equations in the complex plane. Employing two groups of potential functions for solid skeleton and pore fluid (each group includes three functions), the uw formulation of Biot's equations are solved. Difference of these two solutions refers to use of two various potential functions. Equations for calculating stress, displacement and pore pressure fields of the medium are mentioned based on each two formulations. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
890.
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