掺硼金刚石膜电极降解水中全氟辛酸

采用掺硼金刚石膜电极(Boron-doped diamond,BDD)为阳极的电化学氧化法降解全氟辛酸(Perfluorooctanoic acid,PFOA);对比不同电解质体系中PFOA的脱氟效果,考察初始pH、流速、电流密度、初始浓度和电解质浓度对PFOA脱氟率的影响,估算体系能耗;以甲醇(MeOH)和叔丁醇(TBA)为淬灭剂进行自由基淬灭实验,分析PFOA的降解机理。结果表明:Na2SO4电解质体系中,PFOA具有良好的降解效果;酸性条件下(pH为3~4.2)PFOA脱氟效果较佳,中性条件下较差,脱氟效果随初始浓度的增加而降低,随电流密度的增大先提升后趋于稳定。初始pH为3、电流密度30 mA·cm^-2、流速32.5 mL·min^-1、初始浓度100 mg·L^-1、Na2SO4浓度0.05 mol·L^-1条件下,电解180 min,PFOA脱氟率达53.45%,能耗约为1.13 kWh·(g F)-1;硫酸盐体系产生的·OH、SO-4·两种自由基均能氧化降解PFOA。     

离子选择电极法测定土壤中水溶性氟提取液温度的控制方式

采用超声提取法对样品进行预处理,利用离子选择电极法测定土壤中的水溶性氟,超声空化热效应会造成提取液温度升高,检测结果不稳定,不能如实反映土壤中水溶性氟含量,对土壤环境中氟的监测造成困扰.因此,选择有效的控制提取液温度方式至关重要.本文通过记录直接超声、加冰袋、加冰水、冷却循环水四种温度控制方式提取液温度变化确定出最佳温...     

燃烧水解-离子选择电极法测定植物样品中氟含量的方法改进

对燃烧水解-离子选择电极法测定氟离子含量的方法进行改进。采用标准溶液添加法绘制标准曲线,用去离子水吸收,操作简单,减少了误差,适用于低氟植物样品的测定。方法检测限为0.45μg/g,回收率为90.2%~109.7%。将改进的电极法应用于低氟植物试样的检测,结果与离子色谱法测定值相符。     

巴黎城市规划布局规律及特点研究

本文在对巴黎城市布局实地考察的基础上,对城市布局规律及特点进行了较为系统和深入的研究。得出巴黎城市布局的主要特点：（1）选择数个（一般为3个）或在高度或在体量上具有一定特点的建筑物作为整个建筑群的主体性建筑统领全区,使该区内其他的建筑物围绕着这些主体标志规则布局。这就使得上述建筑群的布局大多呈现出“三段式”的典型形式。（2）各区内的建筑物多依其地形、道路的走向规则布局。各建筑物间的组合形式既有方形．长方形,也有梯形、三角形以及不规则的四边形等形状。且各组间多呈闭合状态。（3）在建筑群的中心轴线地带内,均为绿化园林区（带）,各建筑群的布局均主题突出、清晰明确。（4）城市的各交通枢纽（交叉路口）均以城市广场作为其基本的布局形式。各交通枢纽间均以宽阔、笔直的林荫大道相连,且每条大街都通向一处纪念性的建筑物。     

基于水环境约束分区的产业布局引导研究——以江苏省为例(英文)

Along with the highly speedy development of economy and society in the developed area in China,with the sharp increase in the quantity of pollutant discharge such as agricultural fertilizers,industrial wastewater and domestic sewage,the water environment has been deteriorated continuously and then become a restricting factor to regional development.For harmonizing the relationship between economic development and water environment,many countries have been attempting water environmental function zoning so as to provide a scientific basis for the basin management.However,focusing mainly on water body,these researches ignored the spatial relation between water and land as well as the restricted function of water environment on regional industrial layout.So previous index system adapted only to the environmental genes but excluded the stress genes of socio-economic development.This paper,thus,taking both the sensitivity and pressure of water environment into consideration,discusses the methods of constraint regionalization of water environment,including how to divide the assessed units,choose and manage the assessed elements.Then,as a case study,Jiangsu Province is divided into four types of areas by the method of quadrant analysis,i.e.,high-pressure and high-sensitivity area (HP-HS Area),high-pressure and low-sensitivity area (HP-LS Area),low-pressure and high-sensitivity area (LP-HS Area) and low-pressure and low-sensitivity area (LP-LS Area).Finally,this paper presents the schemes of industrial layout and the policy of industrial development direction respectively,which are very important bases for harmonizing the industrial development and the bearing capacity of water environment.     

缬氨霉素铷离子选择电极的制备和应用

缬氨霉素为中性载体的PVC膜铷离子选择电极有较好的选择性,KpRotb,K=0.35。该电极已用于铷的分析测定和含Rb+的水和醇水体系的热力学性质的研究。     

水平电极撒样法光谱定量分析硼

以SiO2(天然)∶C∶NaF=100∶50∶9为缓冲剂,Ge作为内标,水平电极撒样法光谱测定B.方法的测定范围为w(B)/10-6=3～200,检出限为3×10-6.方法经国家一级标准物验证,测定结果与标准值相符.     

倾斜摄影设备选型及像控点布设对高精度实景三维模型重建的影响

在高精度实景三维模型生产中,无人机平台与载荷的选择及像控点布设十分重要,对航摄效率、模型精度、效果均有影响。本文以我国北部某城镇村为研究区域,利用不同的无人机倾斜摄影测量设备分别获取同分辨率倾斜影像,并结合不同的像控点布设方案重建实景三维模型。通过同等分辨率原始影像的不同装备及像控点布设的组合方案构建对照试验组,对比验证并分析飞行效率、模型精度及模型效果,选取满足高精度实景三维模型重建要求的设备类型及经济合理的像控点布设方案,为实际的生产作业提供指导。     

电导电极比测实验及其误差分析

260型电导电极能满足日常地震观测要求,但其精度在观测高和低电导率水样时有所不同;电导池常数的标定对电导率的日常观测是非常关键的,准备一支备用电导电极以确保电导观测的精度,提高观测数据的质量。     

Stability analysis of a fire-loaded shallow tunnel by means of a thermo-hydro-chemo-mechanical model and discontinuity layout optimization

When subjected to fire loading, shallow tunnels may experience loss of stability. This may result in large deformations and ultimately in local collapse of such structures. High temperature has a great negative influence on tunnels, not only because of thermal-induced mechanical degradation of the heated lining but also because of thermal spalling in consequence of the build-up of pore pressure. Thermal spalling causes quick loss of lining sections. Mechanical degradation sole can be simulated by thermo-mechanical models, while consideration of mechanical degradation and spalling requires thermo-hydro-chemo-mechanical (THCM) models and a spalling criterion. After simulation of both processes, the stability of a tunnel structure can be assessed by means of limit analysis. In this work, at first, a fully coupled THCM model is developed. Then, by using a “stress vs strength” criterion and a boundary shifting strategy, the coupled mechanical degradation and thermal spalling processes are captured, providing time-dependent and space-dependent information of the heated lining. Finally, a novel numerical approach, termed discontinuity layout optimization (DLO), is applied to quantify the stability of the tunnel structure with the help of a factor of safety. The proposed numerical procedure is used to conduct numerical studies with, as well as without, consideration of spalling. The results show that spalling has a great impact on the stability of the tunnel. It reduces the thickness of the lining section and accelerates the heating process of the inner concrete.