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11.
突发性水污染事故的应急处理 总被引:9,自引:1,他引:9
近年来,我国城市水源地突发性污染事件日益增加,如何保护水源地生态环境安全和城市供水系统安全,以及如何快速、有效地处理突发性水污染事故已成为亟需解决的问题。介绍了突发性水污染事故应急处理的一般程序,重点讨论了应急措施、处理技术及区域污染物的处理方法。对于危及城市自来水厂区域的突发性污染事故,若在其处理能力范围内,可采用强化混凝、三级处理、备用水源地取水、开启与邻近城市间的备用供水管网等应急处理方法向城市供水;对于自来水厂取水口等遭受污染的水域,可采用吸附、化学沉淀、化学氧化、强化消毒等方法对不同污染物进行治理或隔离。 相似文献
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Effect of different size of planer joint enlargement as a noninvasive and practical strategy for seismic retrofit of gravity load designed external reinforced concrete beam‐column connections was experimentally investigated. The joint region was enlarged using steel angles that are mounted using prestressed cross‐ties. Reverse cyclic load tests on five half‐scale control and retrofitted external RC beam‐column connections were conducted. Three different size of planer joint enlargement being 180, 140, and 90 mm were considered for retrofitted specimens. The performance of the retrofitted specimens is compared with that of the control gravity load designed beam‐column connections, in terms of load–displacement hysteresis curve, energy dissipation and ductility capacities, and global strength and stiffness degradation behavior. The experimental results showed that increasing the size of planer joint enlargement significantly enhances the seismic capacity of the retrofitted connections, in terms of strength, stiffness, energy dissipation, and ductility capacity and also planer joint enlargement can relocate beam plastic hinges to outside the joint panel. 相似文献
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The relationship between heart failure (HF), sleep-disordered breathing and cardiac arrhythmias is complex and poorly understood. Whereas the frequency of predominantly obstructive sleep apnea in HF patients is low and similar or moderately higher to that observed in the general population, central sleep apnea (CSA) has been observed in approximately 50% of HF patients, depending on the methods used to detect CSA and patient selection. Despite this high prevalence, it is still unclear whether CSA is merely a marker or an independent risk factor for an adverse prognosis in HF patients and whether CSA is associated with an increased risk for supraventricular as well as ventricular arrhythmias in HF patients. The current review focuses on the relationship between CSA and atrial fibrillation as the most common atrial arrhythmia in HF patients, and on the relationship between CSA and ventricular tachycardia and ventricular fibrillation as the most frequent cause of sudden cardiac death in HF patients. 相似文献
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从机动车行车过程的舒适性角度出发,介绍了车辆行驶舒适性概念,通过分析单个车辆的行驶状态突变特征,构建了面向车辆行驶过程的适用于城市道路的舒适性评价指标体系。 相似文献
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Hiroshige Kumamaru 《Journal of Nuclear Science and Technology》2017,54(2):242-252
Three-dimensional numerical calculations have been performed on the magnetohydrodynamic (MHD) flows through a rectangular channel with sudden expansion, particularly in order to estimate the pressure drop through the sudden expansion. The sudden expansion is in the directions both perpendicular and parallel to the applied magnetic field. The Hartmann number, the Reynolds number and the magnetic Reynolds number are set to ~100, ~1000 and ~0.001, respectively, in simulating laboratory conditions. The continuity equation, the momentum equation and the induction equation were solved numerically by the finite difference method as discretization following the MAC method as solution procedure. On the whole, in the sudden expansion in the direction perpendicular to applied magnetic field, the loss coefficient is estimated to be nearly zero or small. In particular, the loss coefficient becomes negative for small aspect ratios. The reason of negative loss coefficient is attributable to decrease in the induced current just upstream of the expansion. On the other hand, in the sudden expansion in the direction of applied magnetic field, all the cases give positive and large loss coefficients, meaning that the pressure drop through the expansion becomes large. In particular, the loss coefficient becomes considerably large when the Hartmann number increases. 相似文献
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腔耦合双J-C模型中原子纠缠的猝灭和猝生 总被引:2,自引:2,他引:0
研究了腔间有耦合的双J-C模型中原子纠缠的动力学, 分析了腔间耦合系数A和原子的初态对原子纠缠的猝灭(ESD)和猝生(ESB)的影响. 通过对原子间共生纠缠度的数值分析发现, 当原子初态为第一类类Bell态时, 不会出现ESD和ESB, 腔间的耦合可使原子的纠缠加大, 并能使初态为分离态的原子产生纠缠. 当原子初态为第二类类Bell态时, A的大小可改变出现ESD与ESB的时间间隔, 或决定是否出现ESD, 但腔间的耦合不能使初态不纠缠的原子产生纠缠. 相似文献
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突变环境下的人体热反应是由许多主客观因素所决定的,利用神经网络具有通过学习最佳逼近非线性映射的能力,将其应用于突变环境下人体热反应的研究,具有一定的可行性。本文通过局部非均匀环境与背景均匀环境之间的过渡实验,利用Matlab工具,分别建立了向热环境过渡和向冷环境过渡的整体热感觉以及头部执感觉的BP(Back Propagation)神经网络热舒适评判模型。经验证,该模型对不同工况过渡后的逐时热感觉预测较为准确,从而为非均匀环境与均匀环境之间过渡的热舒适模型的建立提供了一种可借鉴的方法。 相似文献