浅析虹吸滤池的运行故障

虹吸滤池是一种不需专用冲洗设备,利用滤池本身的出水水头进行反冲洗的滤池,和一般滤池相比,具有操作管理简单方便、易于自动控制、无需大型阀门和专用反冲洗设备的优点,在供水行业得到广泛的应用。宣城供水总公司在1996年鳌峰水厂扩建时,兴建了一座虹吸滤池,共分6格,产水量1800m3/h,滤速10m/h,冲洗强度15L/(s·m2)。在长期运行管理过程中,遇到一些常见故障浅析如下:1单池进水量小,几乎不工作(1)检查进水虹吸管、阀门、接头是否漏气。虹吸滤池系水力自动反冲洗,整个管道为真空系统,如果管道系统存在漏气现象,将影响虹吸的形成,造成进水量小…     

V型滤池的运行与维护

本文介绍了河口净化站在原有虹吸滤池基础上改造后的V型滤池在设计施工及生产运行维护过程中出现的问题及解决办法。并就V型滤池运行一年来的实践经验提出对此种滤池自动化技术改造的一些体会。     

水厂配水系统与配水均匀度合理性的探讨

水厂滤池极限穿透深度与配水板水头损失之间存在一定的关系,通过对虹吸滤池小阻力配水系统的探讨,推导出了在一定条件下,配水板水头损失越大．配水均匀度越好。     

虹吸滤池高度与设计滤速关系的分析

本文试图通过对虹吸滤池高度(着重在最大过滤水头)与滤速之间关系的分析,对几种滤速概念的阐述,以及对设计滤速选择问题的讨论,以探讨虹吸滤池设计高度(最大过滤水头)校核的目的、内容和方法,同时对现行的一些经验数据或参数(如设计滤速、冲洗水头、最大过滤水头等)之间的内在关系进行了阐述和论证。     

医院污水处理设施的分析与探讨

根据环境保护总体发展的要求，医院污水必须经治理达标后，才能排入环境水体．为了节省能源和避免二次环境污染，实践证明，采用生物膜滤池与双虹吸同步定量加氯法相结合的污水处理设施，是一种设施简单，操作方便，结果可靠，很有实用价值和技术推广价值的医院污水处理设施。     

基于π定理的虹吸式出水管原型和模型虹吸形成时间的相似分析

基于π定理的量纲分析方法,对大型泵站虹吸式出水管虹吸形成过程中水力驱气阶段、水力挟气阶段和虹吸稳定流阶段水流特征量进行了量纲分析,分析了原、模型虹吸形成各阶段所应遵循的流体力学相似准则。结果表明:在重力相似条件下建立物理模型时,在虹吸形成过程的水力挟气阶段和虹吸稳定流阶段,模型的历时与原型相似;在水力驱气阶段,虹吸形成时间除受到Froude数影响,还受到Weber数和Euler数的影响。在进行虹吸式出水管模型试验研究时,仅保持重力相似的模型装置而不考虑Weber数及Euler数的影响,会引起原、模型间比尺效应问题,通过模型预测的虹吸形成时间将比原型的虹吸形成时间偏小。     

船坞虹吸灌水廊道驼峰压强计算及最优半径的确定

针对近年来广泛应用的虹吸灌水廊道中的驼峰负压和虹吸段半径.通过在柱坐标系下建立虹吸段水流运动方程,推导出了驼峰断面流速和压强的解析表达式,并用水力模型试验结果验证了压强表达式的准确性.在此基础上提出了廊道虹吸段最优半径的确定方法,对比分析了已有方法得出的最优半径下的断面压强分布,并对某廊道的虹吸段半径进行了优化试验,均验证了最优半径确定方法的有效性.     

同步去除氨氮和铁、锰的滤池中细菌群落解析

针对以黄河沿岸地下水为水源的东周水厂生产性砂滤池,利用克隆文库的方法解析了滤池内细菌群落结构.研究结果表明,锰砂滤池内细菌群落多样性较低,而硝化螺旋菌门是优势菌,证实了该滤池实际已经成为硝化生物滤池.硝化螺旋菌属和生丝微菌属的共存解释了硝化滤池内生物除锰的可行性.为今后同步去除氨氮和锰的地下水滤池的设计和管理提供了一些微生物学基础信息.     

虹吸法排除滑坡体中的深层地下水

本文通过虹吸法排除滑坡深层地下水的具体实例,介绍了虹吸法排除滑坡深层地下水的施工工艺,探讨了该排水方法中虹吸井点的数量及其排列的理论计算方法,提出了应该特别注意的问题,供滑坡排水工程实践参考。     

港口岸坡采用虹吸排水技术的实验室效果模拟

以三峡库区奉节某货运码头为原型,于实验室模拟了港口岸坡虹吸排水技术。结果表明：对于渗透性较大的岩土体,岸坡虹吸排水效果不明显．而对于渗透性较小的岩土体．岸坡虹吸排水效果明显。港口岸坡虹吸排水系统中汲水井的间距越小或控制排水面积越小,则越能提高岸坡的虹吸排水效果。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has