云南省旅游资源与生态安全协调发展的时空演化特征及障碍因子分析

自然、经济和社会构成的复合生态系统为旅游资源的赋存和开发提供条件,而丰富的旅游资源不仅能够促进旅游业发展,也为推动社会经济发展和自然环境保护提供了重要力量.运用线性加权法、耦合协调度模型和趋势分析等方法探究了云南省16个州市旅游资源与生态安全耦合协调发展现状及其障碍因子,研究发现:①尽管云南87.50％的州市旅游资源与...     

“一带一路”沿线国家气象服务的供需协调度分析

基于2011—2020年“一带一路”沿线国家气候风险、灾损情况、经济水平,以及市场环境等方面数据资料,从气象服务供需视角,构建气象服务供需协调度指标体系,采用熵值法和协调度耦合模型量化分析沿线国家气象服务的需求、供给及供需均衡水平。结果表明,灾情指标和人口密度指标能较好地表征需求和供给水平;南亚的印度、巴基斯坦、孟加拉和东南亚的菲律宾等国家的气象服务需求相对较高;供给指数相较需求指数更加稳定;均衡指数在研究期内的波动范围变化不大,但是空间分布格局变化较大;沿线印度、新加坡和孟加拉三国的均衡性上升趋势最为显著。     

1957—2017年厦门市马銮湾国土开发动态规律

以厦门市马銮湾为研究区,从规模、速度和结构3方面全面分析了1957—2017年马銮湾陆域和海域土地利用的演变特征.结果表明:(1)60年间马銮湾从半农半渔的农村地区发展到现在高度城市化的城区,经历了"滩涂大开发-养殖和工业快速扩张-城镇扩张"的国土开发过程,土地利用变化速度呈加快趋势,后30年为前30年的2.1倍,近1...     

铝硅酸盐矿物和玻璃中Al的配位与局部结构

利用同步辐射的AlK边X射线吸收近进结构（XANES）谱研究了刚玉和铝硅酸盐矿物（蓝晶石,红柱石,夕线石和钠长石）中Al的配位与局部结构,证明该方法可以作为新的结构探针研究结构未知体系中Al的配位与局部结构。例如,Al的K边XANES谱证明在室温压条件,钠长石玻璃中的Al保持为四面体配位（AlIV）,局部结构与钠长石晶体中的Al相似;尽管硬玉晶体中的Al为八面体配位,但硬玉玻璃中的Al变为四面体配位（AlIV）。而在相同的高温压条件（4．4GPa,1575C）下制备的硬玉-钠长石玻璃系列中,压力引起四面体配位的Al变成五次（Alv）和六次配位（AlVl）,且五次和六次配位Al的比例随玻璃中硬玉含量的增加而增大。     

托换桩-土钉墙组合支护结构的工作机制初探

针对新型托换桩-土钉墙组合支护结构,假定沉降大于托换桩沉降范围内的坡顶建筑物荷载全部转移至托换桩,阐述托换桩-土钉墙组合支护的工作机制,对支护结构的变形协调机制和荷载传递路径进行探讨,提出支护结构侧向变形、坡顶沉降以及托换桩沉降及内力的计算方法。参数及对比分析表明,相对传统的复合土钉墙支护,新型托换桩-土钉墙组合支护结构可以很明显地减小支护结构的变形和内力,随坡顶荷载的增加托换支护法中支护结构的内力和变形的增速明显小于复合土钉墙的内力和变形增速,随微型桩水平间距的增加支护结构的变形和内力都增加,微型桩嵌固深度的增加对支护结构的内力和变形影响较小。     

柔性基础下群桩复合地基荷载传递规律及计算

复合地基沉降及荷载传递规律的研究是复合地基理论中一项非常重要的研究内容,然而对群桩复合地基的沉降及荷载传递规律的研究,在理论上很不成熟。在采用文[1]推荐的竖向变形模式及文[2]推荐的径向变形模式的基础上,利用弹性理论及桩-土位移协调条件建立了桩及桩周土的控制微分方程,并由此推导出了柔性基础下群桩复合地基加固区内桩及桩周土压缩量计算的解析式,同时得出了桩、桩周土中竖向应力及桩侧剪应力计算的解析式。通过算例将该方法所得结果与有限元结果进行了对比,同时也与模型实验结果进行了比较。算例及模型实验结果均表明：该方法对分析柔性基础下群桩复合地基的荷载传递规律及加固区的变形具有足够的精度,且该法计算工作量小,便于工程应用。     

From impacts assessment to adaptation priorities: the shaping of adaptation policy

Abstract

Under the United Nations Framework Convention on Climate Change (UNFCCC), adaptation has recently gained importance, yet adaptation is much less developed than mitigation as a policy response. Adaptation research has been used to help answer to related but distinct questions. (1) To what extent can adaptation reduce impacts of climate change? (2) What adaptation policies are needed, and how can they best be developed, applied and funded? For the first question, the emphasis is on the aggregate value of adaptation so that this may be used to estimate net impacts. An important purpose is to compare net impacts with the costs of mitigation. In the second question, the emphasis is on the design and prioritisation of adaptation policies and measures. While both types of research are conducted in a policy context, they differ in their character, application, and purpose. The impacts/mitigation research is orientated towards the physical and biological science of impacts and adaptation, while research on the ways and means of adaptation is focussed on the social and economic determinants of vulnerability in a development context. The main purpose of this paper is to demonstrate how the national adaptation studies carried under the UNFCCC are broadening the paradigm, from the impacts/mitigation to vulnerability/adaptation. For this to occur, new policy research is needed. While the broad new directions of both research and policy can now be discerned, there remain a number of outstanding issues to be considered.     

城市更新过程中流动人口居住-就业变动的协同机制研究——以北京为例

城市更新过程中流动人口面临居住与就业的不稳定.本文构建流动人口居住与就业协同变动的理论分析框架,使用北京大样本问卷调研数据,基于双层级双变量离散选择模型,分析城市更新背景下流动人口居住-就业变动协同性及其与背景环境的关系.结果发现:流动人口的居住/就业变动概率远高于本地人口,城市更新对流动人口居住和就业的不稳定性影响更...     

Socioeconomics effects on global hotspots of common debris items on land and the seafloor

Pollution of coastal environments by anthropogenic debris is a global problem that is increasingly in the public eye. We evaluated the influence of socioeconomic and geographic factors on common debris items at a global scale. We compared debris density and socioeconomic drivers of the ten most common items reported on land and the seafloor, analyzing data from 22,508 land-based and 7,290 seafloor clean-ups and surveys across 116 and 118 countries, respectively. We found debris hotspots for different items span numerous countries across all continents. This demonstrates that the debris problem is global and heterogeneous, pointing to the transboundary nature of the issue and necessitating sub-national approaches to implementing effective solutions. Food and beverage packaging items, predominantly made from single-use plastics, accounted for much of the debris. Hotspots of individual debris items were differentially driven by socioeconomic factors. In general, total debris counts increased with the value of infrastructure, and decreased with national wealth. Highly polluted sites occurred in high-infrastructure, low-wealth locations such as Athens, Greece; Tunis, Tunisia and Lima, Peru. Based on these findings, we identify specific opportunities for policy makers and citizens alike to focus efforts aimed at reducing debris entering the environment.     

中国气候变化南南合作对《巴黎协定》后适应谈判的影响

适应气候变化是发展中国家的重要谈判议题。《联合国气候变化框架公约》2015年达成《巴黎协定》后如何落实适应议题实施细则成为关注焦点。发达国家以温室气体排放总量大为理由,施压中国等发展中大国出资全球适应气候变化行动;发展中国家内部对适应气候变化受害方和出资方的划分存在较大分歧,造成适应议题下发展中国家集团难以形成合力,《巴黎协定》实施细则谈判进展缓慢。中国气候变化南南合作作为中国与其他发展中国家之间重要的气候变化领域合作形式,能否通过寻找发展中国家契合点,依据合理机制,对适应谈判发挥一定作用,须及早进行利弊分析及顶层设计。文章通过分析美欧日对外援助的机制、梳理非洲小岛国等主要发展中国家集团在应对气候变化不利影响方面的需求、总结以往中国适应项目对外援助情况的基础上,提出了今后中国气候变化南南合作与适应谈判中需要注意的问题,包括区分适应援助和减缓援助、避免中国气候变化南南合作的属性被误读等问题,为争取广阔外交利益、合理构建南南合作机制提供政策建议。