Invasive species change detection using artificial neural networks and CASI hyperspectral imagery

For monitoring and controlling the extent and intensity of an invasive species, a direct multi-date image classification method was applied in invasive species (salt cedar) change detection in the study area of Lovelock, Nevada. With multidate Compact Airborne Spectrographic Imager (CASI) hyperspectral data sets, two types of hyperspectral CASI input data and two classifiers have been examined and compared for mapping and monitoring the salt cedar change. The two types of input data are all two-date original CASI bands and 12 principal component images (PCs) derived from the two-date CASI images. The two classifiers are an artificial neural network (ANN) and linear discriminant analysis (LDA). The experimental results indicate that (1) the direct multitemporal image classification method applied in land cover change detection is feasible either with original CASI bands or PCs, but a better accuracy was obtained from the CASI PCA transformed data; (2) with the same inputs of 12 PCs, the ANN outperforms the LDA due to the ANN’s non-linear property and ability of handling data without a prerequisite of a certain distribution of the analysis data.     

The research of air pollution based on spectral features in leaf surface of Ficus microcarpa in Guangzhou, China

Nowadays development of industry and traffic are the main contributor to city air pollution in the city of GuangZhou, China. Conventional methods for investigating atmosphere potentially harmful element pollution based on sampling and chemical analysis are time and labor consuming and relatively expensive. Reflectance spectroscopy within the visible-near-infrared region of vegetation in city has been widely used to predict atmosphere constituents due to its rapidity, convenience and accuracy. The objective of this study was to examine the possibility of using leaves reflectance spectra of vegetation as a rapid method to simultaneously assess pollutant (S, Cd, Cu, Hg, Pb, XCl, XF) in the atmosphere of the Guangzhou area. This article has studied the spectral features of polluted leaf surface of Ficus microcarpa in 1985 and 1998. According to the analysis, comprehensive assessment for the change of atmospheric condition and degrees of pollution were given. This conclusion was confirmed by the monitored data got from chemical analysis. Future study with real remote sensing data and field measurements were strongly recommended.     

大气预浓缩仪-GC/FPD测定环境空气中的痕量硫化物

采用大气预浓缩仪-GC/FPD建立了环境空气中7种含硫化合物的测定方法。结果表明,经惰性化改造后的大气预浓缩仪-GC/FPD测定系统的基线低,对硫化物无残留。7种化合物的线性回归方程的相关系数均在0.995以上,高、中、低3种浓度的空白加标回收率分别为98.6%~105.3%、99.1%~103.7%、85.7%~99.7%,除硫化氢的相对标准偏差为10.9%外,其余6种含硫化合物的相对标准偏差可控制在6.9%以内。当进样体积为400 m L时,方法的检出限在0.10~1.1 ng/m3。CO2、H2O对实际样品的测定无干扰。因此,该方法能够满足目前监测工作的要求,更加适用于环境空气中痕量含硫化合物的测定。     

超声提取-气相色谱质谱法测定大气PM2.5中正构烷烃

建立了超声提取-气相色谱质谱法测定大气PM2.5中32种正构烷烃方法,经离子温度优化、前处理比较、空白滤膜考察等获得了最佳的实验条件。研究发现,高、中、低3种浓度标准曲线的相关系数均在0.995以上,3种浓度的空白样品加标回收率分别为72.2%~117.8%、73.5%~104.4%、73.8%~109.5%,精密度均小于10%,实际样品加标回收率为75.7%~108.9%。当采样体积为24 m3时,各目标化合物的方法检出限为0.046~2.6 ng/m~3;经正构烷烃浓度范围为0.17~64.3 ng/m~3的1月及浓度范围为0.53~7.67 ng/m~3的6月的实际样品验证,该方法的检出限和测量范围也可较好的满足实际样品的测定。     

测量土壤中多溴联苯和多溴联苯醚含量不确定度评定

通过对气相色谱-质谱联用法测定土壤中多溴联苯和多溴联苯醚类化合物含量的不确定度进行评定,分析了测量过程中引入的不确定度来源,求出各不确定度分量,最后合成标准不确定度并计算相对扩展不确定度。结果表明,各化合物最大的不确定度分量是方法回收率,约占50%~90%,方法相对扩展不确定度为0.12~0.20。     

采用微电极测定溶解氧有效扩散系数的研究

生物载体内部溶解氧的传质是影响载体同步硝化反硝化性能的重要因素.介绍了一种以溶解氧微电极为测试工具,获得球形生物载体内部溶解氧扩散系数的方法.采用自制的溶解氧微电极检测沿载体半径方向上的溶解氧分布,结合扩散-反应方程拟合获得载体内部的溶解氧有效扩散系数.结果表明,在载体填充率为25%的情况下,连续流球形载体反应器可实现同步硝化反硝化,对有机物的去除负荷达到5.6 kg/(m³·d).沿载体半径方向里层1/2区域范围内溶解氧消耗为零,载体内能够形成明显的缺氧/厌氧区.溶解氧分布曲线的拟合结果表明,载体内部溶解氧有效扩散系数为0.017?2　m²/d,传质过程以紊动传质为主.     

渗流式生物床处理污染河水性能的研究

渗流式生物床是受严重污染小型河流强化治理的适宜技术,在中国北方河流污染的治理中有良好的应用前景。冬季由于水温较低带来的去除效果下降是北方河流污染治理的关键问题,本研究在现场中试基础上,考察了一年四季不同水温条件下渗流式生物床处理污染河水的性能。研究表明:渗流式生物床对河水中的CODCr、NH3-N、浊度有较好的去除效果。去除效果和去除负荷受水温影响较大。     

棉浆黑液生物处理工程改造及运行

介绍了某化纤厂黑液生物处理系统的工艺改造及运行情况。通过采取对废水进行清污分流,提高进水CODCr,延长废水水力停留时间,并将原“厌氧→好氧”工艺改为“好氧→厌氧”工艺等改造措施,实现了黑液生物处理系统的稳定运行;厌氧池由半瘫痪状态转入正常运行,并有大量沼气产出,CODCr总去除率达55%;取消无轴锥筛,停止硫酸、尿素和磷酸的投入,使运行费用降至原来的1/3。系统改造取得了较好的效果。     

A/DAT-IAT生物脱氮工艺短程硝化反硝化

研究了A/DAT-IAT生物脱氮工艺在低溶解氧浓度下,处理高氨氮、低碳氮比工业废水时,去除氨氮过程中亚硝酸盐积累的情况。结果表明,系统在低DO浓度下有效去除氨氮的同时,能够实现长期稳定的亚硝酸盐积累,并且没有发生污泥膨胀。在试验的稳定运行阶段,当系统运行正常,DO=1·0mg/L时,DAT池亚硝化率(NO2--N/NOX--N)平均可达82·1%,氨氮去除率>95%,污泥的沉降性能一直良好,SVI值处于90~125mL/g范围内。     

升流式污泥床对无机废水中氮硫转化及相互影响

采用无机含氨和硫酸盐(SO₄^2-)废水作为升流式污泥床(USB)反应器进水,研究了其对铵(NH₄⁺)和SO₄^2-的去除以及不同高度污泥层含氮、硫元素的转化途径.结果表明在反应器进水口处由于进水自含氧(外源性氧)和兼性厌氧菌受到氧化应激产生过氧化氢(内源性氧),两种“氧”共同存在下,反应器内生物脱氨量(以氮计)最高达40mg/L左右,且在USB反应器不同高度污泥层含氮化合物和含硫化合物的转化途径不同.在反应器底部污泥层,颗粒污泥表面氨氧化菌利用O₂将氨(NH₄⁺)氧化成亚硝酸盐(NO₂^-),在颗粒污泥内部厌氧氨氧化菌利用NH₄⁺和NO₂^-生成氮气(N₂)和硝酸盐(NO₃^-);同时,O₂