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21.
Continuous visibility monitoring has been carried out inKwangju, Korea since May 1999. The total light extinctioncoefficient b
ext measured by a transmissometer andreveals seasonal trends in urban visual air quality,especially under hazy conditions with a visual range of lessthan 15 km. Seasonal atmospheric visibility under lowrelative humidity during the winter was observed to be betterthan during any other seasons. Summertime visibility wasseverely degraded due to highly increased light scattering byhygroscopic particles under high humidity atmosphericconditions. Visibility during spring and fall was alsomoderate. However, yellow sand in spring caused the lowestvisibility conditions over the measurement area for a fewdays. With continuous monitoring using the transmissometer,the daily average seasonal visual range was measured to be13.1, 9.2, 11.0, and 13.9 km in spring, summer, falland winter, respectively. Under the atmospheric humiditycondition less than 60%, visual range was observed tobe 16.1, 13.9, 15.1, and 16.6 km in spring, summer,fall, and winter, respectively. The mean light extinctionbudget by sulfate and nitrate aerosols was determined to bethe highest value of 63.71% during the summer and thelowest value of 27.08% during spring. During the `yellow sand dust' period, a mean light extinction budget by soil particles was estimated to be at an unusually high value of 44.22%. 相似文献
22.
Kalra N Jain MC Joshi HC Chaudhary R Kumar S Pathak H Sharma SK Kumar V Kumar R Harit RC Khan SA Hussain MZ 《Environmental monitoring and assessment》2003,87(1):93-109
Field experiments were carried out during 1996–97at Gulawathi, Muthiani and Salarpur Villages, IARI Farm, NewDelhi and NCPP Campus, Dadri to evaluate changes in soilcharacteristics and growth of wheat (Triticum aestivum L.),mustard (Brassica juncea L.), lentil (Lence esculentaMoench.), rice (Oryza sativa L.) and maize (Zea mays L.) byvarying amounts of flyash addition (up to 50t ha-1) in soils atsowing/transplanting time of crops. Flyash addition in areasadjoining NCPP Thermal Power Plant, Dadri, Ghaziabad, U.P.ranged from 5–12 t ha-1 yr-1 in 1995–96. Shoot and root growthand yield of test crops at different locations after flyashincorporation resulted in beneficial effects of flyashaddition in most cases. The silt dominant texture of flyashimproved loamy sand to sandy loam textures of the surfacesoils at the farmers' fields. The increased growth in yield ofcrops with flyash incorporation was possibly due tomodifications in soil moisture retention and transmissioncharacteristics, bulk density, physico-chemical characterssuch as pH and EC and organic carbon content. The response offlyash addition in the soil on soil health and cropproductivity needs to be evaluated on long-term sustainableaspects. 相似文献
23.
SBR法处理中药材有机废水工艺研究 总被引:2,自引:0,他引:2
应用SBR法对中药材有机废水进行了研究。考察了CODCR、BOD5、SS、NH3-H的处理效果,以及PH、水温、污泥负荷等条件对去除率的影响。运行结果表明,PHO 6.0-9.0、t为15-30℃、污沁荷0.3kgBOD5/kgMLSS.d,运行程序:进水0.5h(限制曝气)、曝气10h、脱氮1.5h,沉降0.5h,排水0.5h、闲置11h,周期时间24h时CODCR去除率88%、BOD594%、 相似文献
24.
利用两次金汞齐-冷原子荧光光谱法,对贵州省废弃汞矿山万山矿区地表水不同形态汞(活性态、溶解态、颗粒态)的含量进行测定。样品活性态汞为1.04~402 ng/L;溶解态汞为12.5~426 ng/L;颗粒态汞变化很大,最低只有1.38 ng/L,最高达4 427 ng/L。研究表明:(1)直接与矿山冶炼活动排放物炉渣接触的溪流水污染程度最高,总汞高达4.46μg/L;(2)与矿山开采活动排放的废石或贫矿石接触的溪流水污染程度较低;(3)远离汞矿开采、冶炼活动区的地表水总汞接近汞矿化带背景参考值。 相似文献
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GeochemicalcharacteristicsofrareearthelementsinWuhansectionoftheYangtzeRiverWangLijun;ZhangShen;ZhangChaosheng(InstituteofGeo... 相似文献
29.
The feasibility of decomplexation removal of typical contaminants in electroplating wastewater, complexed Cu(II) with 1-hydroxyethylidene-1,1-diphosphonic acid (Cu-HEDP), was first performed by a three-dimensional electric
reactor with activated biochar as particle electrodes. For the case of 50 mg/L Cu-HEDP, Cu(II) removal (90.7%) and PO
initial pH 7, acid-treated almond shell biochar (AASB) addition 20 g/L, and reaction time 180 min, with second-order rate constants of 1.10 × 10−3 and 1.94 × 10−5 min−1respectively. The growing chelating effect between Cu(II) and HEDP and the comprehensive actions of adsorptive accumulation, direct and indirect oxidation given by particle electrodes accounted for the enhanced removal of Cu-HEDP, even though the mineralization of HEDP was mainly dependent on anode oxidation. The performance attenuation of AASB particle electrodes was ascribed to the excessive consumption of oxygen-containing functionalities during the reaction, especially acidic carboxylic groups and quinones on particle electrodes, which decreased from 446.74 to 291.48 µmol/g, and 377.55 to 247.71 µmol/g, respectively. Based on the determination of adsorption behavior and indirect electrochemical oxidation mediated by in situ electrogenerated H2O2 and reactive oxygen species (e.g., •OH), a possible removal mechanism of Cu-HEDP by three-dimensional electrolysis was further proposed. 相似文献
30.
基于土地市场交易结构的视角,测算2000-2016年黄河流域104个地级以上城市一级土地市场化程度,综合利用Global Moran's I、G*i指数空间统计模型对其时空格局演变特征进行分析,运用灰色关联度分析模型探究土地市场化时空格局演变的主要驱动因素。研究发现:2000-2016年,黄河流域土地市场化水平表现出先持续上升后不断下降的阶段性变化特征,呈现了“东高西低”的空间分异格局。黄河流域土地市场化水平整体具有显著的空间自相关性,土地市场化热点区域以下游主要城市为核心,经历了先加速蔓延、后缓步收缩的时空演进历程。黄河流域土地市场化水平的时空格局演变主要由经济发展水平、产业结构升级、固定资产投资、政府财政收支比、外商直接投资以及区位条件等因素共同驱动,但受我国社会经济发展的阶段性影响,各因素在不同年份的影响程度存在显著的差异性。 相似文献