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51.
深圳河湾污水截排工程投资超过人民币5亿元。工程方案坚持以科学的发展观为指导,将节水与防污相结合,将发展循环经济作为方案研究的出发点与落脚点,对深圳河湾流域的污水处理尾水排海、污水资源化、水体生态修复等作出了长远规划。  相似文献   
52.
Modification of rainfall-runoff processes by urban infrastructure and anthropogenic activities impacts receiving waters and the surrounding terrestrial environment. Infiltration–exfiltration systems such as a partial exfiltration reactor (PER) when loaded by transient sheet flow have the potential to attenuate the impact of both the quantity and quality of urban runoff. These in situ systems are subject to highly variable water quality and quantity while functioning under variably saturated flow conditions. To improve the understanding of field-scale PER performance as a rainfall-runoff unit operation and process, a two-dimensional (2D) numerical model was used to simulate the effluent hydrograph and water content profiles under transient hydraulic loadings. Richard’s equation was applied in the 2D model using parameters estimated from laboratory experiments and hydrographs measured for an in situ PER. The temporal dynamics of the water content illustrated the ability of the PER to lower peak flow, redistribute volume, and attenuate temporal aspects of the inflow hydrograph. Results demonstrated the role of the PER to attenuate runoff water quantity, while also providing water quality improvements, as illustrated for suspended solids and dissolved Cu. Simulation of historical events for different surrounding soils illustrated the critical role of surrounding soil conditions on PER performance. While the PER demonstrated water quantity attenuation benefits for design storms (1, 2, 5?year return periods), results also illustrate how a given PER design for clayey soils conditions can be limiting for intense events. Evaporation was a dominant mechanism for the drying process in the PER upper layer; with a residual moisture content in the porous pavement layer achieved in less than 2?days in summer for Cincinnati, Ohio.  相似文献   
53.
Pollution Buildup on Road Surfaces   总被引:1,自引:0,他引:1  
Samples of sediment found on an urban road in Aberdeen (Scotland) were collected by washing designated surfaces. This method, called the “wet” method, was capable of collecting sediment of the smallest particle size range that is normally left behind by traditional sampling techniques using dry vacuuming. Over 17 months (mainly on a weekly basis), 66 samples were collected and analyzed for sediment loading, particle size distribution, concentration of heavy metals (Zn, Cu, Pb, Cd) in four sediment size fractions, and several dissolved pollutants in the effluent collected from washing (NO3?,?SO42?,?PO43?,?Cl?,?F?,?NH4+, total organic carbon, total carbon). Standard statistical methods, including multiple regressions, were used to determine relationships amongst different sediment characteristics. It was found that sediment loading, as well as concentrations of Cl? and SO42?, were highest in the winter months, especially when snow was present on the road surface. It was observed that 66% of total road sediment loading was found within a 0.5 m strip next to the curb. The average sediment particle sizes found were smaller than those previously recorded in the literature. As expected, the concentrations of heavy metals were highest in the smallest particle size fraction analyzed (<63?μm), and this occurred during the summer months when less sediment was available on the street surface. The antecedent dry weather period had a very weak and negative influence on the loading rate of the smallest particle size fraction next to the curb.  相似文献   
54.
司马昶 《铜业工程》2005,(4):59-60,69
本文针对刚性防水屋面渗漏的原因进行了分析,并提出了处理措施,旨在控制刚性防水屋面渗漏的产 生,保证屋面质量,满足使用要求。  相似文献   
55.
A new analytical method is proposed for the analysis of boundary effect in a pipe bend portion loaded by bending moment combined with internal pressure. The proposed method is based on the simplifying hypotheses, which make possible to represent all deformation- and force-related parameters in terms of the tangential displacement assumed in the form of the Fourier series expansion by the circumferential coordinate. A set of quadric differential equations by axial coordinate containing unknown displacement expansion coefficients is derived. We obtained an analytical approximate solution for a pipe bend portion and precise solution for a straight pipe, which are expressed via Krylov functions. We formulate the application procedure for the method of initial parameter, where the values of tangential and longitudinal displacements, axial and tangential forces are used as boundary conditions. We present the equations relating the above-mentioned parameters in the initial and end sections of the pipe bend portion. The results obtained are compared with the available published data. __________ Translated from Problemy Prochnosti, No. 4, pp. 64 – 94, July – August, 2005.  相似文献   
56.
飞行时间质谱峰形分析   总被引:1,自引:1,他引:1  
从离子运动方程出发,用峰形分析方法离子的质谱峰进行数据再处理,首次从飞行时间质谱峰峰形中获得离子产生时的空间分布信息。这种峰形分析方法可以广泛应用于分析飞行时间质谱的各种离子源中离子的分布。  相似文献   
57.
将初参数法与优化方法相结合,提出了阶梯主轴部件刚度的计算方法.这一方法很适合在计算机上对多支承主轴的刚度作精确计算.  相似文献   
58.
本文运用语言学理论对印欧语系的原始词根进行了全新的分析和综合,揭示了词根字母排列组合的内在规律、首位字母的宏观倾向性语义及词根语义的相互关系。这有助于加深对印欧语系原始母语的了解,促进对其所派生的现代相关语言的研究。  相似文献   
59.
预烧淬火速度对NiCuZn铁氧体性能的影响   总被引:1,自引:0,他引:1  
采用传统的氧化物法制备NiCuZn铁氧体,预烧保温后采用了三种不同方式冷却,研究了冷却速度对材料微观结构和磁性能的影响。发现随着冷却速度的加快,可获得更好微观结构、更高起始磁导率、更低损耗、更高烧结密度之低温共烧材料。  相似文献   
60.
The analysis of root-mean-square simulation of the initial boundary-value problems of the dynamics of distributed-parameter systems is continued. The authors formulate and solve minimization problems for the simulation errors by optimizing observations of the initial and boundary conditions and by selecting reference points for simulation functions.Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 45–57, September–October 2004.  相似文献   
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