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401.
Amounts of readily soluble nutrients on asphalt parking lot surfaceswere measured at four locations in metropolitan Phoenix, Arizona, U.S.A. Using a rainfall simulator, short intense rainfall events were generated to simulate `first flush' runoff. Samples were collected from 0.3 m2 sections of asphalt at 8 to 10 sites on each of four parkinglots, during the pre-monsoon season in June-July 1998 and analyzed for dissolved NO3 --N, NH4 +-N, soluble reactive phosphate (SRP), and dissolved organic carbon (DOC). Runoff concentrations varied considerably for NO3 --N and NH4 +-N (between 0.1 and 115.8 mg L-1) and DOC (26.1 to 295.7 mg L-1), but less so for SRP (0.1 to 1.0 mg L-1), representing average surface loadings of 191.3, 532.2, and 1.8 mg m-2 respectively. Compared with similar data collected from undeveloped desert soil surfaces outside the city, loadings of NO3 --N and NH4 +-N on asphalt surfaces were greater by factors of 91 and 13, respectively. In contrast, SRP loads showed little difference between asphalt and desert surfaces. Nutrient fluxes in runoff from a storm that occurred shortly after the experiments were used to estimate input-output budgets for 3 of the lots under study. Measured outputs of DOC and SRP were similar to those predicted using rainfall and experimentally determined surface loadings, but for NH4 +-N and particularly for NO3 --N, estimated rainfall inputs and surface runoff were significantly higher than exports in runoff. This suggests that parking lots may be important sites for nutrient accumulation and temporary storage in arid urban catchments.  相似文献   
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香港住宅室内环境及污染暴露量研究   总被引:3,自引:0,他引:3  
对选定的14间香港住宅的PM10、CO、NO2等主要室内污染物浓度进行监测,通过建立多元线性回归模型,分析了室内.外PM10浓度与居民室内各种活动等其它有关因素之间的相关关系.结合香港居民日常时间安排调查的结果,计算出各种室内污染物的暴露量,对住宅室内环境污染对居民健康的影响进行了初步评估,提出了改善住宅室内环境的一些建议。  相似文献   
403.
With proximal and distal obstruction to the lacrimal drainage system, mucus accumulates forming a cyst. In order to diagnose a nasolacrimal duct cyst antenatally, the sonographer must image the region adjacent to the orbits.  相似文献   
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Ever since the concept of metabolism was extended from biological science by social scientists to analyze human systems, socio-economic metabolism has been extensively applied to explore resource consumption, asset accumulation, waste emissions, and complex processes of land use change in a socio-economic system. Current research in socio-economic metabolism and land use change has used accounting approaches for macroscopic comparisons of countries and regions. However, socio-economic metabolism has seldom been applied to the analysis of land use change. To simulate the spatial-temporal dynamics of socio-economic metabolism and land use change, this study adopts a spatial system modeling method to develop a Socio-Economic Metabolism and Land Use Change (SEMLUC) model for the Taipei Metropolitan Region. The simulation results illustrate that the Taipei Metropolitan Region is highly dependent on inflows of non-renewable energy and exhibits a spatial hierarchy of non-renewable energy consumption centering on Taipei's Main station. Additionally, urban assets provide feedback to natural and agricultural systems to extract additional resource inflows which, driven by the maximum power principle, accelerate the convergence of energy flows toward urban assets. Accumulating urban assets also facilitates inflows of non-renewable material to nearby cells thereby enhancing land use conversion to urban areas. This work also demonstrates the capability of ArcGIS software in simulating socio-economic metabolism and land use change in an urban system.  相似文献   
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