基于集约评价的城市开发区规模计量研究——以南京市省级以上开发区为例

随着开发区集约利用评价工作的全面开展,合理界定其用地规模成为研究的重点。本文以南京市为例,首先运用多目标决策法评价开发区集约利用等级,然后采用逐步回归法选取与集约利用相关度较大的因素作为预测依据,进而计量其合理的规模。研究结果表明:其一,A、B和C开发区集约等级为II级,可以适当扩大开发区规模;D、E、F和G开发区集约等级为III级,应该维持开发区规模;而H和I开发区集约等级为IV级,应适当缩小开发区规模。其二,当B开发区、A开发区和其他开发区地均工业总产值增长率分别达到23.10%、18.18%和15%时,可以充分发挥土地利用潜力。其三,即使实现土地集约利用,B开发区仍需扩充6.08 km2。最后,本文提出通过科学设定地均工业总产值增长率来提升开发区集约利用水平的政策建议。     

Approach of technical decision-making by element flow analysis and Monte-Carlo simulation of municipal solid waste stream

This paper deals with the procedure and methodology which can be used to select the optimal treatment and disposal technology of municipal solid waste （MSW）, and to provide practical and effective technical support to policy-making, on the basis of study on solid waste management status and development trend in China and abroad. Focusing on various treatment and disposal technologies and processes of MSW, this study established a Monte-Carlo mathematical model of cost minimization for MSW handling subjected to environmental constraints. A new method of element stream （such as C, H, O, N, S） analysis in combination with economic stream analysis of MSW was developed. By following the streams of different treatment processes consisting of various techniques from generation, separation, transfer, transport, treatment, recycling and disposal of the wastes, the element constitution as well as its economic distribution in terms of possibility functions was identified. Every technique step was evaluated economically. The Mont-Carlo method was then conducted for model calibration. Sensitivity analysis was also carried out to identify the most sensitive factors. Model calibration indicated that landfill with power generation of landfill gas was economically the optimal technology at the present stage under the condition of more than 58% of C, H, O, N, S going to landfill. Whether or not to generate electricity was the most sensitive factor. If landfilling cost increases, MSW separation treatment was recommended by screening first followed with incinerating partially and composting partially with residue landfilling. The possibility of incineration model selection as the optimal technology was affected by the city scale. For big cities and metropolitans with large MSW generation, possibility for constructing large-scale incineration facilities increases, whereas, for middle and small cities, the effectiveness of incinerating waste decreases.     

氙灯曝露试验中标准物质的用途及使用方法

本文介绍了氙灯曝露试验中应用的主要标准物质,它们的用途及使用方法,着重介绍了蓝色羊毛标准、聚苯乙烯标准塑料片的应用.     

反渗透阻垢剂YSW-21对硫酸钙的阻垢性能

以丙烯酸为主要单体合成了反渗透阻垢剂YSW-21。通过静态实验法研究了YSW-21对CaSO4的阻垢性能及影响因素。在Ca^2＋质量浓度为7067mg／L、SO4^2-质量浓度为7000mg/L、YSW-21加入量为8mG／L时．YSW-21对CaSO4的阻垢率达91％;在25℃、YSW-21加入量仅为4mg/L时的作用效果长达102h以上;在7500mg/L的高Ca^2＋质量浓度下,YSW-21的阻垢性能优于常用进口阻垢剂大湖135。     

PHB监测A2/O工艺除磷及负荷率耦合关系的研究

以上海市白龙港城市污水厂初沉池污水为进水,培养驯化污泥并构建A²/O试验系统,监测PHB消耗、生成的动态变化,并分析其与除磷和BOD₅负荷率的耦合关系.结果显示,曝气池中PHB的消耗与除磷呈现良好的正相关关系(p<0.05),平均消耗约140 mg左右的PHB可去除1 mg P;厌氧池中PHB的生成与释磷存在着极显著的正相关关系(p<0.01),平均释放1.17 mg的磷可生成约100 mg的PHB;厌氧池中PHB的含量与系统F/M的正相关性显著(p<0.05),负荷为0.176 g/(g·d)较负荷0.413 g/(g·d)下PHB的生成量平均减少约4　mg/g(以MLSS计);PHB的合成与厌氧池中BOD₅的去除量的相关性较差(p>0.05),但与温度呈极为显著的正相关关系(p<0.01),温度的升高有助于微生物合成PHB,最高温度(33.2℃)比最低温度(17.1℃)活性污泥中PHB含量约增加5　mg/g(以MLSS计),占总量的20%左右.     

Sensitivity of the DERMA long-range Gaussian dispersion model to meteorological input and diffusion parameters

The Danish Emergency Response Model of the Atmosphere (DERMA) is described and applied to the first ETEX experiment. By using analysed low-resolution numerical weather-prediction data from the global model of the European Centre for Medium-range Weather Forecast (ECMWF) as well as higher-resolution data from two versions of the High Resolution Limited Area Model (HIRLAM), which are operational at the Danish Meteorological Institute (DMI), the sensitivity of DERMA to the resolution of meteorological data is analysed by comparing DERMA results with concentration measurements. Furthermore, the sensitivity to boundary-layer height and diffusion parameters is studied. These parameters include the critical bulk Richardson number, which is used to estimate the atmospheric boundary-layer height, the horizontal eddy diffusivity and the Lagrangian turbulence time scale. The parameters, which provide the best performance of DERMA, are 0.25 for the critical bulk Richardson number, 6×10³ m² s^-1 for the horizontal eddy diffusivity, and 3 h for the Lagrangian time scale. DERMA is much more sensitive to boundary-layer parameters when using high-resolution DMI-HIRLAM data than when using data of lower resolution from the ECMWF. Finally, the bulk Richardson number method of boundary-layer height calculation applied to DMI-HIRLAM data is verified directly against routine radiosondes released under the tracer gas plume. The boundary-layer height estimates based on analysed NWP model data agree well with observations, and the agreement deteriorates as a function of forecast length.     

基于实验与仿真的三维水下气体泄漏预测与安全评估研究

水下气体羽流特性是海底气体泄漏风险评估的重要基础。为准确预测水下气体羽流行为,基于计算流体动力学(CFD)方法,建立1种考虑气体卷吸湍流特性的三维水下气体羽流数值预测模型;采用欧拉-欧拉流体体积模型捕捉气液作用界面,以大涡模拟(LES)方式预测羽流上浮及卷吸过程中的湍流特性,从而实现对水下气体羽流行为的预测;搭建小尺度实验平台,对比仿真与实验条件下的气体羽流形态,验证数值模型的可行性及预测精度;应用建立的数值模型对工程条件下的水下气体泄漏事故进行预测和评估,以某浅层气井喷事故为例,评估水下气体羽流上浮时间、海面影响范围和涌流高度。结果表明:基于欧拉多相流与大涡模拟的数值模型对水下气体羽流预测结果与实验具有较好的吻合度,该模型能够较好捕捉羽流的湍流特性,可为水下气体泄漏羽流行为评估提供参考。     

林业生产性服务能促进农户林地规模经营吗?--基于林地流入视角的实证分析

厘清林业生产性服务对农户林地规模经营的影响,可为盘活集体林区林地资源、促进家庭林业发展提供决策参考。为考察林业生产性服务对林地规模经营的影响,首先构建了考虑林业生产性服务及林地规模的农户生产模型,通过理论分析后提出假设:林业生产性服务投入增加,将促进农户增加林地要素投入,即林业生产性服务对农户林地规模经营有正向影响。其次,基于福建500份经营商品林农户调查数据,利用Double-Hurdle模型及工具变量处理选择性偏差、遗漏变量及联立因果等引起的内生性问题,实证分析林业生产性服务对农户林地规模经营的影响。结果发现:不同类型的林业生产性服务对农户林地规模经营影响存在差异。其中,林业信贷服务对农户林地规模经营有正向影响,正规信贷与非正规信贷分别使农户林地流入概率提升19.6%、15.9%,使农户林地流入规模分别扩大66.8%、38.5%。林业物资与技术服务仅在是否流入林地阶段对农户林地规模经营有正向影响,使农户林地流入概率提升8.9%。林业劳动力服务仅在林地流入规模阶段对农户林地规模经营有正向影响,使得农户林地流入规模扩大66.9%。林业销售服务由于买方垄断特征对农户林地规模经营有负向影响,使农户林地流入概率降低12.3%,使农户林地流入规模缩减73.2%。因而,政府应有针对地激励和规范各类林业生产性服务发展,以更好地服务于集体林区家庭林业发展。     

A spatially explicit framework for quantifying downstream hydrologic conditions

Continued improvements in spatial datasets and hydrological modeling algorithms within Geographic Information Systems (GISs) have enhanced opportunities for watershed analysis. With more detailed hydrology layers and watershed delineation techniques, we can now better represent and model landscape to water quality relationships. Two challenges in modeling these relationships are selecting the appropriate spatial scale of watersheds for the receiving stream segment, and handling the network or pass-through issues of connected watersheds. This paper addresses these two important issues for enhancing cumulative watershed capabilities in GIS. Our modeling framework focuses on the delineation of stream-segment-level watershed boundaries for 1:24 000 scale hydrology, in combination with a topological network model. The result is a spatially explicit, vector-based, spatially cumulative watershed modeling framework for quantifying watershed conditions to aid in restoration. We demonstrate the new insights available from this modeling framework in a cumulative mining index for the management of aquatic resources in a West Virginia watershed.     

适用于移动平台的河流突发污染溯源算法研究

提出了一种适用于小型移动水质检测平台的一维均一地表水单点源污染物溯源新算法,即通过计算污染物在时间域和空间域的质量浓度导数来反推污染物初始排放点的位置、排放时间及污染物总量.首先,通过算例仿真研究表明,此方法具有较高的溯源精度(与理论距离偏差在10％以内).其次,结合目前移动检测的实际限制(平台长度、取样时间等),对算法中涉及的采样时间、距离等因素的选择进行分析,对移动平台的溯源操作给出了优化建议,以确保有较高的溯源精度.最后,通过实验室水槽缩尺模型试验验证了算法有较高溯源精度(最大偏差在30％以内),从而在原理上证明了该算法适用于特定流域下的移动水质污染溯源.