层次分析法在商场火灾风险评价中的应用研究

根据商场火灾的特点,并基于消防安全和系统安全的思想,从建筑、消防设施、商品、消防管理和外部环境5个方面建立了火灾风险评价指标体系;在此基础上通过层次分析法,计算得出各指标因子的权重值.并根据有关标准和规范,对各评价指标因子的风险分值进行划分.最后采用线性加权模型,计算商场的风险分值,得出火灾风险评价结果.     

Sustainable Development and Transition of Traditional Retailing Centers in Beijing from Consumers' Perspective

Based on the consumer questionnaires of the three traditional retailing centers,Qianmen,Wangfujing and Xidan in Beijing,this article analyzes the present features of consumer composition in the three retailing centers.What is more,the evolution course and function transition of traditional retailing centers is revealed based on the changing of consumer composition in different times.Lastly,the renewal method and development trends of traditional retailing centers are discussed based on the evaluation results in consumers' perspective.     

Ecological and economic impacts of green roofs and permeable pavements at the city level: the case of Corvallis,Oregon

A city's spatial footprint is covered by extensive impervious building roofs and paved surfaces, which contribute to greater storm-water runoff, more surface pollutants, and less carbon sequestration, hence, worse ecosystem services. This research conducts an empirical study on the ecological and economic impacts of a citywide adoption of green roofs and permeable pavements in Corvallis, OR. The effects on ecosystem services of using green roofs and pervious pavements for a low impact development are modelled using Integrated Value of Ecosystem Services Trade-offs and compared to those from the City's current conventional development without green roofs and pervious pavements. The differences are analysed for ecological impact by storm-water yield, storm-water purification, and carbon sequestration and economic impact by a cost-benefit comparison. The results indicate that low impact development, especially intensive green roofs on commercial/industrial buildings and permeable pavements for parking lots, plays a significant role, even with a higher initial implementation cost, for long-term urban sustainability.     

农药生产建设项目环境影响评价的探讨

分析了农药生产建设项目环境影响评价中存在的诸多问题。结合实际工作经验,就农药生产建设项目中的产业政策评价、环境影响的识别、环境风险评价、清洁生产评价和环保治理措施的确定进行了探讨。     

Accumulation and transportation of copper in different ecotypes of Leersia hexandra Swartz

ABSTRACT

This study used hydroponics with different copper (Cu) concentrations to assess metal accumulation and growth in two different populations of Leersia hexandra Swartz, one obtained from a contaminated area (CP) and the other from a non-contaminated area (NCP). Data demonstrated that Cu exerted a lesser effect on the biomass of CP than NCP. The root and shoot biomass measurements of CP were significantly higher than those noted at NCP. Copper concentration in the tissues of L. hexandra from CP increased markedly correlated with the concentration of metal in the culture solution, and this trend was stronger than that in NCP. Copper concentrations in roots and shoots were significantly higher in CP than NCP. As Cu stress levels in the culture solution rose, the transport coefficient of both populations decreased. Furthermore, the coefficient of CP was significantly higher than NCP. At a Cu concentration of 38.4 mg/L, the transfer factor value of CP is 40% higher than NCP. In summary, CP showed higher accumulation and resistance to Cu compared with NCP.     

起重机械作业人员职业适性检测指标研究

采用Ｄｅｌｐｈｉ法对起重机械作业人员职业适性指标进行了研究。咨询专家就各备择指标对工作重要性及发生事故的关系进行了评估。结果表明：专家积极程度与意见集中程度良好；事故重要性与工作重要性排序一致性良好，两者呈高度正相关。依据专家对“重要性”的排序，再通过专家会议与现场考证等方法，最终确定了起重机械作业人员职业适性检测指标体系。     

转轮式洗轮机对车轮带泥的冲洗效果

施工车辆车轮带泥是我国道路扬尘污染控制面临的共性和突出问题。为在国内推广使用洗轮机提供技术依据，通过检测工地出口外道路积尘负荷来估算转轮式洗轮机对车轮带泥的冲洗效率，并以该洗轮机作为车轮带泥检测设备，检测和统计北京市车轮带泥量。结果表明，（1）转轮式洗轮机可以将工地出口外100m道路积尘负荷增量由64．4g／m2降至5．9g／m2，转轮式洗轮机对车轮带泥的冲洗效率大于90％；（2）渣土车和混凝土车车轮带泥量的平均值分别为5．1和2．2kg／车；（3）北京市未来车轮带泥量将超过8．8万t／a，施工车辆全部经过转轮式洗轮机冲洗后，车轮带泥量可削减7．9万t／a。建议在相关法律法规中以强制性条款落实施工车辆车轮带泥机械化冲洗要求。     

CaCu3Ti4O12, an efficient catalyst for ibuprofen removal by activation of peroxymonosulfate under visible-light irradiation

Environmental Chemistry Letters - Contamination of waters by pharmaceuticals is a major health issue. Therefore, there is a need for efficient techniques to remove pharmaceutical pollutants. Here,...     

Electrodialytic soil remediation enhanced by low frequency pulse current – Overall chronopotentiometric measurement

The effect of low frequency pulse current on decreasing the polarization and energy consumption during the process of electrodialytic soil remediation was investigated in the present work. The results indicated that the transportation of cations through the cation exchange membrane was the rate controlling step both in constant and pulse current experiments, thus responsible for the major energy consumption. After 180 h, a decrease in both the initial ohmic resistance in each pulse cycle and the resistance caused by concentration polarization of the anion exchange membrane were seen in the pulse current experiment compared to the constant current experiment. At the cation exchange membrane, only the resistance caused by concentration polarization decreased. In the soil compartment, an average of +60 mV overpotential caused by the polarization of the electric double layer of the clay particles was obtained from the Nernstian behavior simulation of the relaxation process, which was significantly lower than the ohmic voltage drop induced by pore fluid resistance. Therefore, the ohmic polarization was the major contributor to the energy consumption in the soil compartment and diminished by pulse current.     

循环荷载作用下三明治形加筋土挡墙的模型试验与数值模拟∗

为研究循环荷载作用下三明治形加筋土挡墙的受力特性,进行了一系列砂土加筋土挡墙和三明治形加筋土挡墙的动加载室内模型试验.针对不同的加载特征,分析加筋土挡墙的变形和应力响应.采用FLAC3D建立三明治形加筋土挡墙的数值计算模型,通过与模型试验的对比,验证了计算模型的可靠性,分析了循环荷载下挡墙的变形、加速度和潜在破裂面.研究结果表明:三明治形加筋土挡墙变形与竖向土压力随荷载幅值、荷载频率和激振器个数的增加而增大;荷载对土压力的影响随距振源距离的增大而减小;相同加载条件下,三明治形挡墙的顶部沉降更大;随着挡墙高度的增加,土压力的振动幅值逐渐增大,土压力峰值减小;挡墙沉降并非成层均匀沉降,内部分层沉降出现双峰值;随墙高减小加速度衰减,加速度峰值在挡墙上部的平均衰减率最大;三明治形加筋土挡墙与砂土加筋土挡墙破裂面位置相近.地面交通荷载引起的振动对挡墙结构产生不利影响是加筋挡墙的研究重点.