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344.
基于数字流域的水文过程模拟研究 总被引:24,自引:0,他引:24
考虑流域下垫面空间变异性,基于数字高程模型构建了数字流域,并在此基础上对描述流域水文物理过程的数学方法进行了探讨,文章认为,数字水文模型是一种有物理基础的包含大容量信息的现代模拟灌河实例研究表明,数字水文模型可以十分方便地输出水文要素和状态变量的空间分布与时间序列,这对充分利用现有观测信息进行水文信息的深层挖掘创新了条件。 相似文献
345.
346.
物元理论在区域减灾中的应用 总被引:4,自引:0,他引:4
物元分析是解决矛盾问题的规律和方法,是系统科学,思维科学和数学的交叉学科,本文通过具体的事例分析说明自然灾害研究具有发散性,可扩性,相关性的共轭性的特点,鉴于自然灾害的特性,提出了减灾工作应在传统理论研究的基础上,应用物元理论采用可拓学的方法。 相似文献
347.
David Moncoulon Anne Probst Liisa Martinson 《Water, Air, & Soil Pollution: Focus》2007,7(1-3):307-316
To evaluate the acid deposition reduction negotiated for 2010 within the UNECE LRTAP Gothenburg Protocol, sulphur and nitrogen
deposition time-series (1880–2100) were compared to critical loads of acidity on five French ecosystems: Massif Central basalt
(site 1) and granite (2); Paris Bassin tertiary sands (3); Vosges mountains sandstone (4) and Landes eolian sands (5). The
SAFE model was used to estimate the response of soil solution pH and ratio to the deposition scenario. Among the five sites, critical loads were exceeded in the past at sites 3, 4 and 5. Sites
3 and 4 were still expected to exceed in 2010, the Protocol year. Further reduction of atmospheric deposition, mainly nitrogen,
would be needed to achieve recovery on these ecosystems. At sites 3, 4 and 5, the delay between the critical load exceedance
and the violation of the critical chemical criterion was estimated to be 10 to 30 years in the top soil and 50 to 90 years
in the deeper soil. At site 5, a recovery was expected in the top soil in 2010 with a time lag of 10 years. Unexpectedly,
soil pH continued to decrease after 1980 in the deeper soil at sites 2 and 5. This time lag indicated that acidification moved
down the soil profile as a consequence of slow base cation depletion by ion exchange. This delayed response of the soil solution
was the result of the combination of weathering rates and vegetation uptake but also of the relative ratio between base cation
deposition and acid compounds. 相似文献
348.
The present paper describes an effort for developing the total maximum daily load (TMDL) for phosphorus and a load reduction
strategy for the Feitsui Reservoir in Northern Taiwan. BASINS model was employed to estimate watershed pollutant loads from
nonpoint sources (NPS) in the Feitsui Reservoir watershed. The BASINS model was calibrated using field data collected during
a 2-year sampling period and then used to compute watershed pollutant loadings into the Feitsui Reservoir. The simulated results
indicate that the average annual total phosphorus (TP) loading into the reservoir is 18,910 kg/year, which consists of non-point
source loading of 16,003 kg/year, and point source loading of 2,907 kg/year. The Vollenweider mass balance model was used
next to determine the degree of eutrophication under current pollutant loading and the load reduction needed to keep the reservoir
from being eutrophic. It was estimated that Feitsui Reservoir can becoming of the oligotrophic state if the average annual
TP loading is reduced by 37% or more. The results provide the basis on which an integrated control action plan for both point
and nonpoint sources of pollution in the watershed can be developed. 相似文献
349.
Wen-Cheng Liu Jan-Tai Kuo Chih-Chieh Young Ming-Ching Wu 《Environmental Modeling and Assessment》2007,12(3):201-211
Numerical models are often used to evaluate the potential impact of human alternation of natural water bodies and to help
the design of the alternation to mitigate its impacts. In the past decade, three-dimensional hydrodynamic and reactive transport
modeling has matured from a research subject to a practical analysis technology. This paper presents a practical study in
which a three-dimensional hydrodynamic and water quality model [hydrodynamic eutrophication model (HEM-3D)] was applied to
determine the optimal location for treated wastewater discharged from marine outfall system in the Keelung harbor and the
adjacent coastal sea. First, model validation was conducted with respect to surface elevation, current, and water quality
variables measured in the Keelung harbor station and its coastal sea. The overall performance of the model was in qualitative
agreement with the available field data. The model was then used to evaluate several scenarios of the locations from marine
outfall system. Based on model simulation results, a location at the northeast of Ho-Ping Island was recommended for adoption
because the environmental impact is smaller than any other alternative.
相似文献
Wen-Cheng LiuEmail: |
350.
Glucose oxidase is a well-known enzyme that catalyzes the oxidation of β-d-glucose to produce gluconic acid and hydrogen peroxide. Fenton reaction is a powerful oxidation technology used for the oxidation of groundwater pollutants. For the application of Fenton reaction in groundwater remediation, successful operation of Fenton reaction near neutral pH, and on-site generation of both H2O2 and chelate will be beneficial. The focus of this experimental study was to couple the glucose oxidation reaction with chelate-based Fenton reaction. The idea was to use the hydrogen peroxide and chelate gluconic acid generated during glucose oxidation for the dechlorination of 2,4,6-trichlorophenol (TCP) by Fenton reaction. The oxidation of glucose was achieved using the enzyme in free and immobilized forms. The rate of production of hydrogen peroxide was determined for each system, and was used to estimate the time required for complete consumption of glucose during the process, thus avoiding any traces of glucose in the Fenton reaction. In the case of free enzyme reaction, separation of the enzyme was achieved using an ultrafiltration membrane before initiating the Fenton reaction. The oxidation of TCP by Fenton reaction was performed at varying ratios of gluconic acid/Fe, and its effect on the decomposition of TCP and H2O2 was studied. TCP degradation was studied both in terms of parent compound degradation and free chloride generation. 相似文献