城市河网尺度的水体光谱指数适宜性分析研究

城市地表水是城市生态环境的重要组成部分，地表水环境高光谱遥感是高光谱遥感的重要应用方向，水体提取是地表水环境高光谱遥感的第一步，其主要任务是从高光谱遥感数据中提取地表水水体轮廓。基于光谱指数的水体提取方法充分利用光谱信息，计算简单，实现容易，提取效果优异。归一化植被指数(NDVI)、归一化水体指数(NDWI)、高光谱差异化水体指数(HDWI)和基于指数的水体指数(IWI)等光谱指数已经广泛应用于湖泊、大江大河等开阔水体提取。近些年来，随着成像光谱技术的发展，高光谱遥感数据的获取能力也突飞猛进，空间分辨率和光谱分辨率不断提高。与江河湖基本在流域内沿地形分布不同，城市地表水一般细小，纵横交错，形成河网。在高光谱遥感数据用于城市体表水提取时，其面临的图像空间分辨率、地物类型和地物复杂等，与江河湖水体提取有很大不同。因此，需要对这些常用的光谱指数在城市地表水提取中的适宜性进行评价。以此做为出发点和目标，以河网密布的江南水乡中国浙江省嘉兴市为研究对象，以应用型航空成像光谱仪(Airborne imaging spectrometer for applications, AISA)获取的高空间分辨率机载高光谱遥感数据为数据源，通过Youden指数确定最佳阈值，将总体分类精度、错分误差、漏分误差、Kappa系数作为衡量指标，分析评价了NDVI，NDWI，HDWI和IWI 4种光谱指数在城市河网提取中的适宜性。结果表明，阴影与水体光谱变化趋势类似，是造成水体提取过程中高错分误差的主要因素。四种指数都可以准确抑制落在植被中的阴影，但无法有效抑制落在建筑物中的阴影。HDWI虽然可以在一定程度上抑制建筑物中的阴影，但是无法有效地抑制亮建筑物背景。通过对不同类型水体和阴影（笼罩下地物）光谱的进一步分析，虽然水体和阴影光谱曲线变化趋势相似，均在560～600 nm附近存在波峰，但是水体和阴影波峰高度存在差异，水体波峰值较大而阴影波峰值较低。因此，通过充分挖掘水体和阴影在560～600 nm处光谱反射信息，有望进一步抑制建筑物阴影，提高城市河网水体提取精度。     

基于固有光学量的高光谱数据反演城市河网水质

水体辐射传输模型是水体光谱特性分析的理论基础，水体固有光学量由水体组成决定，与水体表面光场无关。基于统计的半经验算法虽然能获取指定区域水质参数反演结果，但是缺乏物理意义；基于生物光学模型的分析算法，针对城市河网内陆Ⅱ类水体光学特性复杂、空间分布异质性强、水体细小、流动性大等特点，利用高光谱数据，研究基于固有光学量的城市河网水质参数反演模型，对内陆城市浑浊水体光谱特性研究具有重大意义。提出了适用于内陆城市河网水体的改进QAA算法，以获取水体固有光学量，改进包括后向散射估计模型调整和参考波段优化两个方面；计算参考波段总吸收系数、颗粒物后向散射系数等固有光学量，得到浮游植物吸收系数和剔除纯水吸收系数；对浮游植物吸收系数最优波段比值与叶绿素a浓度进行线性回归分析，构建叶绿素a水质浓度反演模型，对剔除纯水吸收系数最优波段比值与悬浮物浓度线性回归分析，构建悬浮物水质浓度反演模型。针对内陆河网Ⅱ类水体，以典型的河网城市嘉兴市为研究区域，获取了研究区域航空高光谱数据，以及水质采样化验数据和水面以上光谱数据等地面准同步测量数据；利用QAA算法和IIMIW算法对实测水面以上光谱进行固有光学量反演，对比分析两个算法并结合城市河网水体特点，提出改进QAA算法；利用改进的QAA算法实现了研究区域水体的固有光学量反演，基于反演的水体固有光学量建立了叶绿素a浓度和悬浮物浓度两项水色参数定量反演模型，反演模型决定系数R2分别为0.64和0.71；并用航空高光谱数据同步区域的4个地面样点实测数据，对反演结果进行验证分析。通过水质参数浓度反演值与实测值的对比，叶绿素a和悬浮物水质浓度反演的平均相对误差分别为9.2%和9.4%，反演得到的叶绿素a和悬浮物浓度分布图，也与城市河网的特点和实际情况相符，为城市河网水质监测提供方法和模型参考。     

New low-cost tubular ceramic microfiltration membrane based on natural sand for tangential urban wastewater treatment

In wastewater treatment, the development of low-cost separation methods is of significant importance. Low-cost membranes based on natural materials have become a highly active research topic in recent years. Herein, using low-cost natural Moroccan sand, new ceramic supports have been developed and characterized using different techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA), along with scanning electron microscope (SEM). Plastic paste (average particle size ≤125 µm) was blended with organic additives and water, then the obtained paste was extruded into porous tubular supports. The support had a porosity of 43%, water permeability of 1928 L/h m² bar, excellent chemical and mechanical properties and an average pore diameter in the range of 8–15 µm after firing at 950 °C/2 h. As per SEM analysis, the tubular supports had a smooth and crack-free surface. The slip casting process was used to create a microfiltration layer from the same natural sand powder (average particle size ≤63 µm) using a mixture of powder sand, water, and polyvinyl alcohol solution. The water permeability of the microfiltration membrane sintered at 950 °C/2 h was 1052 L/h m² bar, the average pore size diameter was about 0.90 µm and 82% of pores had a diameter ≤1.00 µm. The obtained microfiltration membrane was tested for the treatment of urban wastewater. The membrane showed excellent separation performance in turbidity removal and chemical oxygen demand.     

湖南大湘西地区城市经济竞争力比较研究

在现有城市经济竞争力分析的国内外研究成果的基础上,依据城市竞争力相关理论,借鉴国内外评价机构的评价模型和分析体系,构建出湖南省大湘西地区城市经济竞争力的评价指标体系,并利用因子分析法对大湘西地区城市经济竞争力进行综合评价,并对各个城市的经济竞争力进行比较研究.在此基础上,有针对性地提出了促进大湘西地区城市经济竞争力提升的对策建议.     

中国战略性新兴产业国际竞争力评价

以"新钻石模型"为基础,从产业环境、产业支撑和产业创新等3个维度构建战略性新兴产业国际竞争力评价指标体系.运用2005~2014年的面板数据对战略性新兴产业进行因子分析.评价结果显示,电子及通信设备制造业与医药制造业国际竞争力明显高于计算机及办公设备制造业与医疗仪器设备及仪器仪表制造业.航空航天器及设备制造业国际竞争力有很大提升潜力.电子及通信设备制造业创新能力表现突出,但战略性新兴产业整体创新能力较低.     

城市环境与地质问题研究现状与发展

本文对本次会议的专题城市环境地质问题进行了综述,对城市地质环境研究进行了展望。     

基于实际路网情境的配送车辆调度优化

在实际路网情境下结合车道数、车道宽度、路口信号灯设置等路网物理特性,构建了考虑综合交通阻抗的多车型车辆调度模型,提出了两阶段求解策略:第1阶段设计了改进A-star精确解算法用于计算客户时间距离矩阵;第2阶段针对实际路网的特征设计了混合模拟退火算法求解调度方案。以大连市某配送中心运营实例进行路网情境仿真试验,结果表明:改进A-star算法较改进Dijkstra算法具有更短的路径搜索时间;混合模拟退火算法求解结果较实际调度方案优化了13.1% 的综合成本;路网增流、区域拥堵和路段禁行三类路网情境均能对配送方案的车辆配置、路径选择、客户服务次序、作业时间和违约费用等5方面内容产生干扰,调度计划的制定需要详细考虑这些因素的变化。     

Taxonomy of batch queueing models in manufacturing systems

Batching plays an important role in performance evaluation of manufacturing systems. Three types of batching are commonly seen: transfer batches, parallel batches and serial batches. To model the batching behavior correctly, a comprehensive classification of batching is proposed. Eight types of batching behavior are classified and corresponding queueing models are given. The newly proposed models are validated by simulation.     

Methodology for Bioassay-Directed Fractionation Studies of Air Particulate Material and Other Complex Environmental Matrices

Abstract

A normal phase HPLC methodology using a semi-preparative polyaminocyano column in conjunction with a selection of short-term genotoxicity assays has been developed for bioassay-directed fractionation studies of complex environmental mixtures. To illustrate the effectiveness of this methodology, an organic extract prepared from respirable air particulate samples collected in Hamilton, Canada was separated into a non-polar aromatic fraction and a polar aromatic fraction using a combination of alumina and Sephadex LH20 chromatography. These fractions were evaluated for their genotoxic potential using the Salmonella/microsome (Ames) assay with six different strains of Salmonella.

The non-polar aromatic fraction was analyzed by normal phase HPLC and the eluent was collected in one-minute subfractions; these subtractions were bioassayed in three different Salmonella strains (YG1021 -S9, YG1024 -S9 and YG1029 +S9) to afford three different mutation profiles of this sample. Some subfractions which exhibited high mutagenic responses were subjected to further chemical analyses using GC/MS in order to identify those compounds responsible for the genotoxic responses. The nitroarene compounds 2-nitrofluoranthene, 1-nitropyrene and 2-nitropyrene and higher molecular weight polycyclic aromatic hydrocarbons such as benzo[a]pyrene and indeno[l,2,3-cd]pyrene were identified and quantified in some of the biologically active subfractions. The normal phase gradient conditions afforded very reproducible retention times for a series of polycyclic aromatic standards with a broad range of compound polarities. In addition, polycyclic aromatic hydrocarbons (PAH) were observed to elute from the normal phase HPLC column in a series of peaks; successive peaks contained PAH of increasing molecular weight while any individual peak was shown to contain PAH of the same molecular weight.