基于云模型的城轨信号系统安全保障能力评价方法*

为准确评价城轨信号系统安全保障能力及影响因素,基于云理论对定性与定量因素的良好融合优点,构建城轨信号系统安全保障能力评价云模型及评价指标体系,采用组合赋权法对各指标赋予权重,并基于专家意见,利用正向云发生器生成标准云。结果表明:该云模型具有一定稳定性和可靠性,可对城轨信号系统安全保障能力进行有效测评,同时能够发现安全运营中的缺陷,有助于协助管理方进行针对性改善,以提高城轨信号系统的安全保障能力。     

两种改良型A~2/O工艺处理城市污水的运行实例

以广东省佛山市甲、乙两间污水处理厂为例,从工艺特征、工艺参数、水质特点、存在问题及相应措施几个方面介绍了两种改良型A2/O工艺在不同进水条件下的运行情况。     

惠阳城区降雨径流重金属污染特征研究：Ⅰ.地表堆积物重金属含量分析

以惠阳城区为研究对象,选取4种具有代表性的典型城市功能区类型:工业区、商业区、住宅区、交通区,对其地表堆积物进行样品采集和实验分析.结果表明:地表堆积物细粒部分(粒径<149舯)所占比例为51%,粗粒部分(粒径>2 000um,)所占比例仅4.1%;重金属含量的粒径分级特性和质量分数相似,即粒径越细的部分重金属含量越高;Pb,Zn,Cu.Cr之间的相关系数较高;重金属的浸出浓度在不同的功能区基本遵循同样的规律,即细粒部分重金属浸出浓度最高,随粒径的增大浸出浓度逐减,细粒部分重金属的浸出浓度:w(Pb)为59.1 rag/kg/kg,w(Zn)为93.5 mg/kg,w(Cu)为37.7 ms/ks,w(Cr)为23.9 ms/kg,w(Cd)为0.07 mg,kg.     

城市生态系统承载机制初步研究

文章分析了城市生态系统组成、结构及功能流,立足于资源承载力、环境承载力的角度,探讨了城市生态系统内部资源、环境对人类社会经济活动的承载约束机制,从城市生态系统客观存在性、弹性与扩展性、递阶性及相对性等方面,总结了城市生态系统承载机制的特点,在建立承载机制评价指标框架的基础上,初步提出了承载机制的定量研究方法。     

发达国家城市环境治理的若干经验

发达国家城市环境治理的经验主要有:完善环境保护法律制度,保证治理措施的有效实施;健全环境管理体系,强化环境行政管理;注意推动自愿性行动来保护环境,积极推动公众参与环境治理;运用经济手段,制定激励奖惩措施,提高环境治理的效率;合理划分环境治理权限,建立权威性的管理机构;大量发展环境教育,通过民众环境保护意识,形成民族心理;加大科技投入,注重科技进步,发展环保产业。这些经验及其教训留给人们诸多启示,值得中国学习与借鉴。     

城市间空气污染控制的马氏链模型

根据城市间空气污染物相互扩散和无后效性的特点,应用马尔可夫随机过程理论,先建立各城市污染物浓度状态转移方程,再由城市间污染物浓度状态形成一个吸收链。建立城市间污染物排放控制的马氏链模型。通过模型求解,得出了城市间空气污染物浓度达到国家排放标准的条件,最后应用数值计算软件MAT-LAB,编写了一个城市间空气污染控制的通用程序,它能在保证城市空气质量的前提下,快速准确地计算出控制区内各污染源污染物的最大允许排放量,这对环保部门进行城市空气污染物排放量控制工作具有实际意义。     

城市绿地结构与鸟类栖息生境的营造

城市化对城市鸟类多样性产生了诸多不利影响。城市绿地结构是鸟类栖息生境选择的重要因素之一。在分析公园面积、连通性、岛屿化等影响城市鸟类多样性的城市绿地结构特征基础上,提出通过优化绿地结构营造鸟类栖息生境的原则,探讨了保护城市自然保留地、建设环城绿化带、构建河岸带与道路绿色廊道、复层植物群落配置、特殊空间绿化等途径作为鸟类生境营造的方法。     

Soil enzyme activities and their indication for fertility of urban forest soil

To reveal the biological characteristics of urban forest soil and the effects of soil enzyme on soil fertility as well as the correlation between physicochemical properties and enzyme activities, 44 urban forest soil profiles in Nanjing were investigated. Basic soil physicochemical properties and enzyme activities were analyzed in the laboratory. Hydrogen peroxidase, dehydrogenase, alkaline phosphatase, and cellulase were determined by potassium permanganate titration, TTC (C₁₉H₁₅N₄·Cl) colorimetry, phenyl phosphate dinatrium colorimetry, and anthrone colorimetry, respectively. The result showed that soil pH, organic carbon (C), and total nitrogen (N) had great effects on hydrogen peroxidase, dehydrogenase, and alkaline phosphatase activities in 0–20 cm thick soil. However, pH only had great effect on hydrogen peroxidase, dehydrogenase, and alkaline phosphatase activities in 20–40 cm thick soil. Hydrogen peroxidase, dehydrogenase, and alkaline phosphatase were important biological indicators for the fertility of urban forest soil. Both in 0–20 cmand 20–40 cmsoil, soil enzyme system (hydrogen peroxidase, dehydrogenase, alkaline phosphatase, and cellulase) had a close relationship with a combination of physicochemical indicators (pH, organic C, total N, available K, available P, cation exchange capacity (CEC), and microbial biomass carbon (C_mic)). The more soil enzyme activities there were, the higher the fertility of urban forest soil. __________ Translated from Urban Environment & Urban Ecology, 2007, 20(4): 4–6, 9 [译自: 城市环境与城市生态]     

An integrated assessment method of urban drainage system:A case study in Shenzhen City,China

In recent years, the urban drainage system in China is facing the dual pressure of renovation and construction. This requires that the integrated assessment for the planning and operation of the urban drainage system is obligatory. To evaluate the urban drainage system, an integrated assessment methodology based on the analytic hierarchy process (AHP), integrated simulation, and fuzzy assessment is established. This method is a multi-criteria decision adding app roach to the assessment of the urban drainage system comprehensively. Through the integration of the Storm Water Management Model (SWMM), a simple wastewater treatment plant model, and a surface water quality model, an integrated modelling system for the urban drainage system is developed and applied as a key tool for assessment. Using the established method, a case study in Shenzhen City has been implemented to evaluate and compare two urban drainage system reno vation plans, the distributed plan and the centralized plan. Because of the particularity of this case study, the established method is not applied entirely. Considering the water environ mental impact, ecological impact, technological feasibility, and economic cost, the integrated performance of the distri buted plan is better. As shown in this case study, the proposed method is found to be both effective and practical.     

生态足迹在城市规划环境评价中的应用——以苏州市域城镇体系规划为例

以苏州市域城镇体系规划为例,探讨运用生态足迹进行融合型规划环境影响评价的方法,为规划环评较早地介入规划编制过程进行了有益的探索：在规划编制初期,确定规划的生态底限,农业用地、非农建设用地和水域的面积不低于3 728、1 016和2 019 km2;在规划编制过程中,根据现状评价的结果提出耕地是苏州城市发展的限制因子,水资源是优势因子,并估算了规划实施前后苏州市的生态足迹和生态承载力的变化情况。结果表明：规划实施后,苏州市的人均生态赤字有加大的趋势,耕地的赤字是最主要的贡献者,草地和能源用地的生态盈亏无变化,林地的生态赤字将减少,建设用地和水域的生态盈余将增加。依据该结果提出了减缓生态赤字的措施以及调整规划的意见：优化城镇发展空间,提高中心城市的容积率,置换出一定面积的生态用地,降低耕地的生态赤字;发展大运量的轨道交通和水路运输,减少交通能耗和机动车尾气的排放,降低能源用地的生态赤字。