Three-dimensional fluorescence spectral characterization of soil dissolved organic matters in the fluctuating water-level zone of Kai County, Three Gorges Reservoir

Three-dimensional fluorescence spectroscopy was used to investigate the fluorescent properties of soil dissolved organic matter (DOM) in the water-level-fluctuation zone (WLFZ) of Kai County, Three Gorges Reservoir (TGR). Most of the soil DOM analyzed in this study was found to contain four fluorescence peaks. Peaks A and C represent humic-like fluorescence, whereas peaks B and D represent tryptophan-like fluorescence. Peaks E and F, which represent tyrosine-like fluorescence, only appeared in certain soils. Soil humus was the main source of DOM in soil, and higher concentration of soil DOM was found in the exposed soil than submerged soil. Compared to the peaks A and B, the fluorescence intensities of peaks C and D were strongly influenced by the fluctuating water level. Analysis of fluorescence intensities of different peaks in soil DOM showed that WLFZ soil was not contaminated significantly. Soil DOM contained at least two types of humic-like fluorescence groups and two types of protein-like fluorescence groups. The proportion of the content of peak A in soil organic matter was quite stable. The soil DOM in exposed soil had relatively high humification and aromaticity, and periodic submerging and exposure of soil had an impact on the humification of soil DOM.     

基于改进微库仑法的海水可吸附有机卤素测定

对可吸附有机卤素(adsorable organic halogens,AOX)测定方法的研究主要集中在河流湖泊等饮用水相关的领域,而海水中的测定方法关注较少.受海水中高浓度的无机卤素离子的影响,传统的微库仑法在测定海水中AOX时精密度会下降并产生较大的正偏差.通过对传统的微库仑法进行改进,采用活性炭振荡吸附法-玻璃棒...     

地理信息系统支持下的区域环境质量现状评价

针对我国区域环境现状评价工作中的实际问题,在地理信息系统PURSIS的支持下,作者设计了一种离散点插值或趋势面拟合扩展的方法,将以往侧重于监测点逐点评价扩展为在整个空间区域上进行评价,即通过扩展模型获得评价因于浓度空间分布图,在此基础上进行环境因子单项或综合评价。在福建湄洲湾环境质量现状评价中,用这种方法,可以统计出污染物的超标面积及分布区域,并进行年际比较,取得了更为科学、实用的评价结果。     

耐候钢-砼组合加劲梁悬索桥极限承载力退化规律研究∗

为制定预防性维护方案提供支撑,探究了悬索桥极限承载力随时间长期退化规律。以我国某公路耐候钢砼组合加劲梁悬索桥为工程背景,建立了考虑钢梁、主缆和吊索三类主要钢构件截面特性与力学性能随时间退化模型;利用梁格法,采用 Mises 屈服准则,考虑几何非线性和材料非线性,基于 U.L. 列式编制杆系有限元计算程序, 计算分析了 3 种最不利荷载工况下的悬索桥的弹塑性极限承载力。结果表明：耐候钢梁的截面积损失 4.5%~ 11.7%,吊索截面积损失 6.8%,主缆截面积损失 1.1%,钢梁退化较快,随着荷载的增大,钢梁塑性区不断扩大使得主缆应力还未达到屈服应力,悬索桥就不能继续承载;荷载‐位移曲线随着桥龄增加表现形式不同,在 20 年以前有明显的拐点;极限承载力呈现缓慢下降的趋势,100 年下降 27.2%~32.4%。     

液态水氢键结构的拉曼光谱研究进展

总结了近年来将拉曼光谱应用于液态水氢键结构的研究进展,分析了温度、压强和电解质对于水团簇氢键网络结构的影响。改变水的温度和压强或加入不同电解质,将会对水的氢键作用产生影响,并改变水分子团簇结构。通过拉曼光谱可以观察到水分子间振动频率的变化,从而推断液态水氢键结构的变化。     

饮用水源水无机金属污染的应急处理

根据密云水库供水现状,针对突发性无机金属污染事件,采用聚合氯化铝辅助化学沉淀法进行应急处理。选用Cu2＋、Fe2＋、Zn2＋和Cd2＋ 4种金属离子为目标污染物,首先通过小试实验确立了最佳混凝处理条件。结果表明,调节pH值为8．0左右,可使初始浓度为5mg／L和10mg／L的Cu2＋浓度降至0．96mg／L和0．67mg／L;初始浓度为1．5mg／L和3mg／L的Fe2＋浓度降至0．27mg／L和0．24mg／L;初始浓度为0．05mg／L和0．1mg／L的Cd2＋浓度降为0．0089mg／L和0．0078mg／L;调节pH值为9．0时,可使初始浓度为5mg／L和10mg／L的Zn2＋浓度降至0．57mg／L和0．48mg／L。4种污染物出水浓度均低于国家饮用水标准。在小试基础上,在北京第九水厂开展无机金属污染处理的中试实验,结果表明所选用的聚合氯化铝辅助化学沉淀法简便易行,可实现污染物快速、有效去除。     

CTMAB／SDS改性沸石对水中痕量邻苯二甲酸酯吸附机制

以季铵盐阳离子表面活性剂CTMAB及阴离子表面活性剂SDS对粉末状天然沸石进行复合改性,制备得到了CTMAB／SDS改性沸石。对改性沸石及天然沸石进行红外吸收光谱及XRD衍射表征,并研究了PAEs在天然沸石和CT-MAB／SDS改性沸石上的吸附机制。结果表明,阴阳离子表面活性剂没有对层状结构的键型造成较大的影响;PAEs在天然沸石和CTMAB／SDS改性沸石上的吸附更符合表面吸附一分配作用复合模型;PAEs的表面吸附和分配作用对吸附作用的贡献主要受吸附剂中有机质含量及吸附物质大小、极性及溶解度的影响。     

Land Degradation Evaluation in North Hebei Province Based on Remote Sensing and GIS

Abstract

Land degradation is one of the serious environmental problems that can lead to poverty, and is especially prominent in eco-fragile areas in developing countries and increases the risk of environmental safety. North Hebei Province belongs to an ecologically fragile region in North China, which has great impact on the eco-safety of Beijing and Tianjin. Using Landsat TM data and GIS, this paper evaluates land degradation in North Hebei province of China from the the 1960's to 1987 and 2000. Land use/cover change pattern from 1987 to 2000, its regional difference and forest change characteristics will also be analyzed; soil erosion intensity and arable land suitability were also evaluated. Results revealed that land use/cover pattern in this study area did not change greatly from 1987 to 2000. The structure and function of regional land ecosystem was at a level of local improvement and integral deterioration. Land above medium soil erosion intensity reached 21 percent, which was also the area with a serious soil erosion and land degradation problem. Soil erosion and land degradation intensity of grassland was the biggest. For the present arable land, the proportion of high suitability was 13 percent.     

软水作为连铸机净环水水质稳定研究

本文对软水作为连铸机净环水的循环冷却水系统水质稳定问题进行研究和探讨。     

水资源水质评价方法分析与进展

对国内外众多的水质评价方法的特点进行了归类分析和比较研究，指出各方法的适用条件和适用范围，提出了设计合理的水质评价模式的特征要求以及今后的研究方向和发展趋势。