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111.
土壤中氯苯类化合物的迁移行为 总被引:8,自引:3,他引:8
为了污染土壤的恢复 ,应用土壤污染实时模拟系统 ,研究土壤中氯苯类化合物的迁移行为 .结果表明 ,氯苯类化合物主要滞留在土壤相中 ,在气、液 2相中的含量随着其蒸汽压和水溶性的增大而增大 ;15cm以上土壤中的氯苯类化合物由最初的均匀分布 ,变为从上至下浓度逐渐增大的分布 .渗滤液中的氯苯类化合物随渗滤水量变化为 2个阶段 ,渗滤水量 <1000 ml时 ,浓度随水量逐渐下降 ;而渗滤水量 >1000 ml后 ,浓度变化不大 ,趋于某一稳定的浓度值 .氯苯类化合物在土壤层和渗滤水中浓度的变化可较好地用吸附模型来解释 .不同氯苯类化合物的挥发速率随时间延长而降低 ,挥发速率与氯苯施加量的对数和蒸汽压呈良好线性关系 . 相似文献
112.
113.
Soon Thiam Khu Shie‐Yui Liong Vladan Babovic Henrik Madsen Nitin Muttil 《Journal of the American Water Resources Association》2001,37(2):439-451
ABSTRACT: Genetic programming (GP), a relatively new evolutionary technique, is demonstrated in this study to evolve codes for the solution of problems. First, a simple example in the area of symbolic regression is considered. GP is then applied to real‐time runoff forecasting for the Orgeval catchment in France. In this study, GP functions as an error updating scheme to complement a rainfall‐runoff model, MIKE11/NAM. Hourly runoff forecasts of different updating intervals are performed for forecast horizons of up to nine hours. The results show that the proposed updating scheme is able to predict the runoff quite accurately for all updating intervals considered and particularly for updating intervals not exceeding the time of concentration of the catchment. The results are also compared with those of an earlier study, by the World Meteorological Organization, in which autoregression and Kalman filter were used as the updating methods. Comparisons show that GP is a better updating tool for real‐time flow forecasting. Another important finding from this study is that nondimensionalizing the variables enhances the symbolic regression process significantly. 相似文献
114.
刘嗣明 《中国人口.资源与环境》2001,11(3):57-61
要劳动力密集型产业就是大量使用劳动力的产业,中国一般地要大力发展劳动力密集型产业的认识已太简单,过时了,所谓劳动力密集型产业,是在世界范围内仍无法用非劳动力要素替代或替代成本过高,仍必须大量使用劳动力要素的产业,这就既要求我们不要把已不是劳动力密集型产业的产业继续人为地搞成劳动力密集型产业;也要求我们去努力寻找并发展真正的劳动力密集型产业,从而为我国众多的劳动力提供就业机会,并使其等量劳动创造等量价值和获得等量收益。 相似文献
115.
为实现以厌氧/好氧方式处理生活污水常低温同时脱氮除磷好氧颗粒污泥(AGS)工艺的实时控制,研究了冬季低温条件下磷负荷变化对系统同时脱氮除磷的影响及DO、pH值和ORP的变化规律;并通过静态实验研究了同时脱氮除磷AGS中聚磷菌(PAO)的组成.结果表明,DO、pH值和ORP的特征点对应反硝化结束、厌氧放磷结束、吸磷结束以及硝化结束等阶段,可以作为AGS同时脱氮除磷的实时控制参数.同时脱氮除磷AGS中,以氧作为电子受体的PAO能够去除总磷酸盐的14.19%;以氧和NO3--N作为电子受体的PAO能够去除总磷酸盐的74.32%;以氧、NO3--N和NO2--N作为电子受体的PAO能够去除总磷酸盐的11.47%.在好氧条件下AGS可以实现同时硝化、反硝化、好氧吸磷和反硝化吸磷. 相似文献
116.
Crystal Pragg 《Chemistry and Ecology》2018,34(7):624-639
Road dust in an industrial estate could potentially contain toxic heavy metals as a result of various anthropogenic sources. This study investigated sixteen samples from various locations throughout the Point Lisas Industrial Estate in Trinidad, West Indies. Samples were acid-digested and analysed by Flame Atomic Absorption Spectroscopy, which revealed that concentrations for Cd, Cr, Cu, Mn, Ni, Pb and Zn ranged from 2.48–5.45?μg/g, 14.2–70.5?μg/g, 15.3–130?μg/g, 219–1330?μg/g, 20.0–62.1?μg/g, 43.5–113?μg/g and 105–1154?μg/g, respectively. Different methods (Geoaccumulation index, pollution index, integrated pollution index, enrichment factor and ecological risk assessment) of assessing heavy metal contamination in road dust indicated negligible to moderate degrees of pollution, in which the associated potential ecological risk was considered low. Principal component analysis (PCA) and Cluster analysis (CA) grouped the heavy metals according to potential sources and indicated that the accumulation of heavy metals in the road dust of the Estate were influenced mainly by vehicular and industrial processes. 相似文献
117.
Jeong-Ha Yoo Sung-Woo Shin Jong Soo Kim Chang-Bae Kim Jong-Sung Kim Sung-Cheol Koh 《Journal of environmental science and health. Part. B》2013,48(4):373-379
A new differential display-polymerase chain reaction (PCR) method based on annealing control primers was used to screen and identify potential biomarkers from differentially expressed genes (DEGs) in medaka exposed to sub-lethal concentration of diazinon (100 ppb). Among the differentially expressed genes identified, the majority were in functional categories of protein biosynthesis, transport and metabolism according to the gene ontology classification. The differential expression of ribosomal protein genes was quantified by real time PCR. The genes encoding ribosomal proteins including L3 and S17 were selected as potential biomarkers for diazinon exposure in medaka fish. 相似文献
118.
Removal of heavy metals using waste eggshell 总被引:2,自引:0,他引:2
PARK Heung Jai JEONG Seong Wook YANG Jae Kyu KIM Boo Gil LEE Seung Mok 《环境科学学报(英文版)》2007,19(12):1436-1441
The removal capacity of toxic heavy metals by the reused eggshell was studied.As a pretreatment process for the preparation of reused material from waste eggshell,calcination was performed in the furnace at 800℃for 2 h after crushing the dried waste eggshell.Calcination behavior,qualitative and quantitative elemental information,mineral type and surface characteristics before and after calcination of eggshell were examined by thermal gravimetric analysis(TGA),X-ray fluorescence (XRF),X-ray diffraction(XRD) and scanning electron microscopy(SEM),respectively.After calcination,the major inorganic composition was identified as Ca(lime, 99.63%)and K,P and Sr were identified as minor components.When calcined eggshell was applied in the treatment of synthetic wastewater containing heavy metals,a complete removal of Cd as well as above 99% removal of Cr was observed after 10 min. Although the natural eggshell had some removal capacity of Cd and Cr,a complete removal was not accomplished even after 60 min due to quite slower removal rate.However,in contrast to Cd and Cr,an efficient removal of Pb was observed with the natural eggshell rather than the calcined eggshell.From the application of the calcined eggshell in the treatment of real electroplating wastewater, the calcined eggshell showed a promising removal capacity of heavy metal ions as well as had a good neutralization capacity in the treatment of strong acidic wastewater. 相似文献
119.
房地产开发建设项目的环境保护验收工作 总被引:1,自引:0,他引:1
本文根据房地产开发项目的特点,总结归纳了此类项目环境保护验收工作的重点内容和法规依据,并提出了相应的污染防治措施. 相似文献
120.
Li Chen 《Journal of the American Water Resources Association》2003,39(5):1157-1165
ABSTRACT: An optimization and simulation model holds promise as an efficient and robust method for long term reservoir operation, an increasingly important facet of managing water resources. Recently, genetic algorithms have been demonstrated to be highly effective optimization methods. According to previous studies, a real coded genetic algorithm (RGA) has many advantages over a binary coded genetic algorithm. Accordingly, this work applies an RGA to obtain the 10‐day (the traditional period of reservoir operation in Taiwan) operating rule curves for the proposed reservoir system. The RGA is combined with an effective and flexible scheme for coding the reservoir rule curves and applied to an important reservoir in Taiwan, considering a water reservoir development scenario to the year 2021. Each rule curve is evaluated using a complex simulation model to determine a performance index for a given flow series. The process of generating and evaluating decision parameters is repeated until no further improvement in performance is obtained. Many experiments were performed to determine the suitable RGA components, including macro evolutionary (ME) selection and blend‐α crossover. Macro evolution (ME) can be applied to prevent the premature problem of the conventional selection scheme of genetic algorithm. The purpose of adjusting a of a crossover scheme is to determine the exploratory or exploitative degree of various subpopulations. The appropriate rule curve searched by an RGA can minimize the water deficit and maintain the high water level of the reservoir. The results also show that the most promising RGA for this problem consists of these revised operators significantly improves the performance of a system. It is also very efficient for optimizing other highly nonlinear systems. 相似文献