机动车不同速度下外噪声变化与衰减关系研究

通过在机动车测试场进行单辆机动车行驶状况的实验,研究机动车车型大小、行驶速度快慢与噪声量大小的关系,同时研究不同距离下机动车行驶外噪声的衰减规律。数据结果显示,测试条件下,噪声量随着速度提升而增加,呈线性关系或对数关系;相同速度下,大型车的噪声量比小型车的高8.1～11.0dB;在一定距离范围内,距离每增加3.5m,机动车噪声量将衰减2.2～3.0dB。     

Municipalities’ ambitions and practices: At risk of hypocritical sustainability transitions?

In contemporary planning discourse and practice, different planning ideas co-exists. How this affects the transition towards a sustainable development is an important question for both research and practice. The aim of this study is to explore potential conflicts between planning goals caught between growth-led planning and sustainability commitments in a case study of Fredericia, Denmark. The paper discusses the underlying, framing and controlling conditions for transition dynamics. The analysis builds largely on the formulated policies, strategies or national goal achievements towards sustainable futures. These are put in the context of planning and political practices, which are interpreted from a sustainability rationale. Here this study introduces hypocrisy as a theoretical-analytical perspective to dispute actual sustainability practices to respond to continuous ambivalent planning measures. The author concludes that disregarding the inherently different internal logics of growths and sustainability leads to planning paradoxes and impedes sustainable transitions pursued.     

中国高速铁路运营的减碳及经济环境互馈影响研究

二氧化碳等温室气体排放备受世界关注,新形势下低碳发展成为中国发展路径的新选择,而高速铁路是长距离运输低碳化的具体体现。基于运营阶段的行车碳排放换算,综合考虑多种交通工具的实际运载能力、标准运行速度等指标,分析中国高速铁路行车运营的减碳效果及经济环境互馈影响。研究发现:(1)以单位运输能耗量及该能源的碳排放系数计算,中国高速铁路行车与其余交通运输方式相比具有显著减碳效果,其百公里人均碳排放量约为航空运输的1/5和高速公路运输的1/3,且随着中国能源结构的逐步优化,减碳效果将会愈发凸显。(2)结合中国旅客周转量比例进行折算,自2008年至2015年高速铁路运输累计减碳2 610万t,从空间上看,省域差距明显,高速铁路运输繁忙的京沪线及京广线沿线地区,成为2015年高速铁路行车运营减碳效果的高值区,亦由此呈现出带状聚邻的正空间自相关性。(3)高速铁路运营产生经济环境的良性互馈影响,一方面环境优化具有潜在经济效益,2008—2015年的减碳效果相当于降低碳交易成本逾10亿元,其绿色设计及应用也益于区域经济发展;另一方面高速铁路运营经济收益具有潜在环境补偿能力,2008—2015年累计对区域节能环保支出贡献逾30亿元,其中高值区以中国中部地区为主,空间分布呈斜T字型结构,其成因与地区节能环保支出占比、出行结构等因素相关。基于上述分析并结合中国发展的客观实际,提出合理增强高速铁路运输效能、继续优化能源供给结构等优化对策,以期从出行视角为中国低碳发展提供交通领域的理论支撑。     

桥梁-道路建设对西南山地城市扩展影响机制研究——以重庆嘉陵江两桥为例

交通因素对城市空间扩展的影响是一个研究热点,但国内外关于桥梁-道路建设对山地城市扩展影响机制的研究还不多见。基于桥梁-道路对城市待开发区域区位的影响,提出了点状辐射、线状辐射和环状辐射3种影响机制。以重庆嘉陵江大桥和黄花园大桥建设对嘉陵江北岸影响为例,将研究区划分为5个分区,基于Arc GIS软件提取各分区城市建成区与河岸的空间分布关系,并通过5个分区1940~2009年城市扩展差异比较印证3种影响机制。研究结果表明,桥梁和道路建设促进研究区建成区迅速扩张,但对不同分区的建成区扩展速度的影响有差异;第3分区城市扩展反映了桥梁-道路对城市扩展的点状辐射和线状辐射,而第4分区城市扩展反映了桥梁-道路对城市扩展的环状辐射。结论表明研究提出的点状辐射、线状辐射和环状辐射符合桥梁-道路建设对西南山地城市扩展的影响机制。     

Reconnecting Cities to the Biosphere: Stewardship of Green Infrastructure and Urban Ecosystem Services

Within-city green infrastructure can offer opportunities and new contexts for people to become stewards of ecosystem services. We analyze cities as social–ecological systems, synthesize the literature, and provide examples from more than 15 years of research in the Stockholm urban region, Sweden. The social–ecological approach spans from investigating ecosystem properties to the social frameworks and personal values that drive and shape human interactions with nature. Key findings demonstrate that urban ecosystem services are generated by social–ecological systems and that local stewards are critically important. However, land-use planning and management seldom account for their role in the generation of urban ecosystem services. While the small scale patchwork of land uses in cities stimulates intense interactions across borders much focus is still on individual patches. The results highlight the importance and complexity of stewardship of urban biodiversity and ecosystem services and of the planning and governance of urban green infrastructure.     

A holistic life cycle analysis of waste management scenarios at increasing source segregation intensity: The case of an Italian urban area

Life cycle analysis of several waste management scenarios for an Italian urban area was performed on the basis of different source segregation collection (SS) intensities from 0% up to 52%. Source segregated waste was recycled and or/recovered by composting. Residual waste management options were by landfilling, incineration with energy recovery or solid recovered fuel (SRF) production to substitute for coal. The increase in fuel and materials consumption due to increase in SS had negligible influence on the environmental impact of the system. Recycling operations such as incineration and SRF were always advantageous for impact reduction. There was lower impact for an SS of 52% even though the difference with the SS intensity of 35% was quite limited, about 15%. In all the configurations analyzed, the best environmental performance was achieved for the management system producing SRF by the biodrying process.     

The Dynamics of Urban Ecosystem Governance in Rotterdam,The Netherlands

We explore whether Rotterdam city has the governance capacity in terms of processes at place, and the attention in terms of vision and strategy to take up an integrated approach toward urban resilience. We adopt an interpretative policy analysis approach to assess the dynamics of urban ecosystem governance considering interviews, gray literature, and facilitated dialogues with policy practitioners. We show the inner workings of local government across strategic, operational, tactical, and reflective governance processes about the way urban ecosystems are regulated. Despite the existing capacity to steer such processes, a number of underlying challenges exist: need for coordination between planning departments; need to ease the integration of new policy objectives into established adaptive policy cycles; and need to assess the lessons learnt from pilots and emerging green initiatives. Regulating and provisioning ecosystem services receive heightened policy attention. Focus on regulating services is maintained by a policy renewal cycle that limits and delays consideration of other ecosystem services in policy and planning.     

北京地区大气氨时空变化特征

在北京城区和上甸子本底地区分别开展了为期3a和1a的NH₃在线观测,并结合风向、风速、温度、相对湿度等气象因素的变化特征,分析了北京地区NH₃浓度水平、年季特征及影响因素.结果发现,北京城区和本底地区的NH₃年均浓度分别为（32.5±20.8）×10^-9V/V和（11.6±10.3）×10^-9V/V,北京城区的NH₃浓度高于大多数国内外主要城市和地区的NH₃浓度水平.城区和本底地区NH₃浓度年变化特征为夏季高,分别为（34.1±6.8）×10^-9V/V和（11.1±2.2）×10^-9V/V,冬季低,分别为（19.7±9.3）×10^-9V/V和（2.4±0.6）×10^-9V/V.NH₃的日变化特征受气象因素影响明显,其结果表明,春季城区NH₃浓度峰值出现在15：00,而本底地区受西南风影响在20：00达到峰值;夏季城区NH₃浓度最高值在7：00出现,本底地区则呈现双峰值（分别在09：00和22：00）;秋季城区和本底地区的日变化规律一致,均在22：00出现峰值;冬季城区的峰值出现时间晚于本底地区,峰值分别出现在23：00和20：00.西南风是造成本底地区NH₃浓度升高的主要原因,春季和夏季,随着西南向风速的增大,NH₃浓度显著升高.城区的NH₃浓度则主要受到局地排放的影响.浓度权重轨迹法的研究结果发现,北京、天津、河北及河南北部地区是影响北京地区大气NH₃的主要源区.     

片岩隧道变形规律分析与预测方法研究*

为准确掌握片岩隧道变形规律,基于隧道变形监测结果,利用核极限学习机构建隧道变形初步预测模型,通过遗传算法和蚁群算法进行优化处理,以保证模型参数的最优性,采用混沌理论对预测误差进行修正处理,利用M-K分析判断隧道变形趋势,并将趋势判断结果与预测结果对比。结果表明:通过递进优化处理,能逐步提高预测精度,且预测结果的相对误差均值介于1.77%~1.83%,均小于2%,具有较高的预测精度;隧道变形虽呈增加趋势,但随时间增长其增长趋势逐渐减弱,总体趋于稳定方向发展。     

城市轨道交通噪声测试分析

采取1/3倍距法布设测点,使用多通道噪声分析系统,对城市轨道交通噪声进行地面和轨面上的水平测试及垂向测试,取得其距离衰减规律、声级垂向分布等特性,新的测试点位布设方案取得了比传统测试方案更详细的测试结果。研究结果对于城市轨道交通噪声特性的研究及其控制方法的确定具有重要的学术意义和工程价值,同时对城市轨道交通噪声的测试方案进行了有益的探索。