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121.
地表水COD浓度灰色预测的GPPM(1)模型   总被引:2,自引:0,他引:2  
王国平 《干旱环境监测》2000,14(1):39-42,49
根据地表水中COD浓度的时序数据,建立了GPPM(1)预测模型,结果表明GPPM(1)模型的预测精度优于常规灰色GM(1,1)模型,它为环境系统的拟合,预测和决策提供了新的方法途径。  相似文献   
122.
建立了水和气样中1-甲基-2-吡咯烷酮的高效液相色谱-串连四极杆质谱测定方法。水样经0.45μm滤膜可直接进样,气样中的1-甲基-2-吡咯烷酮经活性炭吸附后,经30%乙腈水溶液洗脱后进样,最低检出质量达0.012ng;线性范围在0.001~2mg/L;方法灵敏度高,干扰小,定性能力强,快速简单,回收率良好。  相似文献   
123.
CBERS-2B数据提取平原区细小地物系数的方法探讨   总被引:1,自引:0,他引:1  
利用Landsat TM等中等分辨率影像对区域生态环境进行监测与评价时,由于影像分辨率的局限性,仍有许多地物无法解译出来,如农田中的道路、水渠等,文章主要研究了利用图像融合增强和人机交互式解译等技术方法,对CBERS-2B的CCD影像和HR影像进行处理,提取平原区农田中道路面积比系数,从而将农田中未解译的地物扣除。结果表明,CCD影像与HR影像经过融合增强处理后,可以进行平原地区村级及以上道路的提取。  相似文献   
124.
Wang X  Liu X  Wang H  Dong Q 《Chemosphere》2007,67(11):2156-2162
A species of bacteria that is capable of utilizing imazaquin as the sole carbon source was isolated from soil with repeated imazaquin applications, and was identified as Arthrobacter crystallopoietes (designated as strain “WWX-1”). This isolate degrades imazaquin as high as 200 μg ml−1, and the estimated dissipation half-lives increased from 1.51 d for the treatment at 50 μg ml−1 to 4.75 d for 200 μg ml−1. Optimal growth of WWX-1 in mineral salt medium with 50 μg ml−1 imazaquin was obtained at 35 °C and a pH of 5.0. Growth of WWX-1 was also observed in mineral salt medium with the addition of other imidazolinone herbicides such as imazethapyr and imazapyr, but not with different classes of herbicides such as metsulfuron-methyl. Two imazaquin metabolites were detected, and spectral analysis with HPLC–MS, 1H NMR, and IR revealed one metabolite with a molecular weight (MW) of 199 as quinoline-2,3-dicarboxylic anhydride. We propose that A. crystallopoietes (WWX-1) could serve as an efficient biodegradation system for remediation of water and soils that are heavily contaminated with imazaquin or other structurally similar chemicals.  相似文献   
125.
The potential contamination of groundwater by herbicides is often controlled by processes in the vadose zone, through which herbicides travel before entering groundwater. In the vadose zone, both physical and chemical processes affect the fate and transport of herbicides, therefore it is important to represent these processes by mathematical models to predict contaminant movement. To simulate the movement of simazine, a herbicide commonly used in Chilean vineyards, batch and miscible displacement column experiments were performed on a disturbed sandy soil to quantify the primary parameters and processes of simazine transport. Chloride (Cl(-)) was used as a non-reactive tracer, and simazine as the reactive tracer. The Hydrus-1D model was used to estimate the parameters by inversion from the breakthrough curves of the columns and to evaluate the potential groundwater contamination in a sandy soil from the Casablanca Valley, Chile. The two-site, chemical non-equilibrium model was observed to best represent the experimental results of the miscible displacement experiments in laboratory soil columns. Predictions of transport under hypothetical field conditions using the same soil from the column experiments were made for 40 years by applying herbicide during the first 20 years, and then halting the application and considering different rates of groundwater recharge. For recharge rates smaller than 84 mm year(-1), the predicted concentration of simazine at a depth of 1 m is below the U.S. EPA's maximum contaminant levels (4 microg L(-1)). After eight years of application at a groundwater recharge rate of 180 mm year(-1) (approximately 50% of the annual rainfall), simazine was found to reach the groundwater (located at 1 m depth) at a higher concentration (more than 40 microg L(-1)) than the existing guidelines in the USA and Europe.  相似文献   
126.
建立煤矿安全生产状况预测的非线性回归模型、混沌动力学模型、灰色模型和灰色残差模型,用4种模型对我国百万吨煤矿死亡率进行预测分析,其结果表明:混沌动力学预测模型和非线性回归模型使用参数较少、计算简单,易于推广,但预测精度尚不高,误差较大;使用灰色残差模型进行预测,虽然计算复杂,但预测精度较高,验证2007年度百万吨死亡率相对误差仅为0.96%,煤炭生产的安全性指标百万吨死亡率宜采用残差模型进行预测。笔者认为,灰色残差模型在对煤矿安全生产的宏观管理领域有广泛的应用前景。  相似文献   
127.
Photocatalytic degradation of disperse blue 1 using UV/TiO2/H2O2 process   总被引:1,自引:1,他引:0  
The photocatalytic degradation of a dye derivative, C.I. disperse blue 1 (1), has been investigated under UV light irradiation in the presence of TiO2 and H2O2 under a variety of conditions. The degradation was studied by monitoring the change in substrate concentration employing UV spectroscopic technique as a function of irradiation time. The degradation was studied under different conditions such as different types of TiO2, reaction pH, catalyst and substrate concentration containing hydrogen peroxide (H2O2), besides molecular oxygen in the presence of TiO2. The degradation of dye was also investigated under sunlight and the efficiency of degradation was compared with that of the artificial light source. The degradation rates were found to be strongly influenced by all the above parameters. The photocatalyst Degussa P25 was found to be more efficient for the degradation of the dye.  相似文献   
128.
王秀芳  刘国荣  朱珈 《环境技术》2008,26(1):22-24,45
本文简述电气领域如何评定测量不确定度过程,并结合CNAS T0346低温试验能力验证计划,识别和具体分析低温试验中各测量不确定度的来源,对各种影响因素进行评价,论述人、机、料、法、环、测各环节对测量结果的影响,给出了低温试验测量结果不确定度的评估过程。  相似文献   
129.
Over three million dry metric tons of biosolids produced in the United States are land applied as Class B. Lime stabilization is employed for biosolids treatment at approximately 20% of the wastewater treatment plants because it is a simple and inexpensive process. During lime stabilization, the pH of sewage sludge is raised above 12 for pathogen inactivation and odor reduction. Lime dose and mixing have been found to greatly reduce odor generation from lime stabilized biosolids. A better quality biosolids product is less likely to create public opposition to land application programs. In this study, land application tests using Class B biosolids were conducted in order to determine whether better mixing can reduce odor generation during the land application of lime stabilized biosolids. The mixing quality of a treatment plant’s lime stabilized biosolids was improved by relocating the lime addition point, which prolonged the mixing time and produced a better mixed biosolids product. Based on field observations of land application, the poorly mixed biosolids were more odorous and offensive prior to incorporation. However, once incorporated into the soil, there was no appreciable odor difference between the biosolids. Another land application study was conducted to assess the odor of unincorporated Class A biosolids and compare it with incorporated Class A biosolids with the soil.  相似文献   
130.
雷州半岛桉林-砖红壤水分动态变化特征研究   总被引:1,自引:0,他引:1  
根据定位观测数据,对雷州半岛浅海沉积物发育的桉林地砖红壤水分状况及其动态变化进行了初步探讨.结果表明,受水分蒸发量大等因素的影响,0~100 cm土层月均贮水量较低;主要受降雨分布的影响,土壤水分呈明显的季节性变化特征且季节性干旱时间较长,8~  相似文献   
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