检索结果-南通市图书馆

Detection of subcritical crack propagation for concrete dams

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2009年第12期52卷 3654-3660页

作者： bao tengfei1 ,2.yu hong 1,2.1college of water conservancy&hydropower engineering,{3.,nanjing 2.0098,China 2National engineering Research Center of water Resources Efficient Utilization and engineering Safety,nanjing 2.0098,China college of water conservancy & {3. engineering Hohai University Nanjing China National engineering Research Center of water Resources Efficient Utilization and engineering Safety Nanjing China

Subcritical propagation of cracks is a warning sign of *** such propagation is detected at an early stage,timely maintenance measures can be taken to prevent the failure of *** detect the subcritical propagation of a crack,the crack needs to be monitored continuously in a long term, which is not realistic under certain ***,cracks in concrete dams can be monitored continuously by dam monitoring to offer possible detection for subcritical *** this paper, with measured crack openings from dam monitoring,a state equation for characterizing crack development is established based on the grey system *** relation between the stability of the equation and the subcritical crack propagation is investigated,then a criterion is proposed for detecting subcritical *** example demonstrates the validity of the criterion and its potential for practical application.

关键词： crack subcritical propagation criterion concrete

Back analysis of mechanical parameters of roller compacted concrete dam

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2010年第3期53卷 848-853页

作者： GU ChongShi 1,2,3.LI Bo 1,XU GuangLei 4 &yu hong 1,2,3.1 State Key Laboratory of Hydrology-{3. Resources and Hydraulic {3.,hohai university,nanjing 2.0098,China 2college of {3. conservancy hydropower,hohai university,nanjing 2.0098,China 3.ational {3. Research Center of {3. Resources {3. Safety,Efficient Utilization and nanjing 2.0098,China 4 nanjing Hydraulic Research Institute,nanjing 210029,China State Key Laboratory of Hydrology-water Resources and Hydraulic engineering Hohai University Nanjing China college of water conservancy {3. Hohai University Nanjing China National engineering Research Center of water Resources engineering Safety Efficient Utilization and Nanjing Nanjing China nanjing Hydraulic Research Institute Nanjing China

In view of the diversity and complexity of mechanical parameters of roller compacted concrete dam(RCCD),the uniform design method,partial least-squares regression(PLS)and least squares support vector machine(LSSVM)were applied to the back analysis of RCCD with the use of the complex nonlinear relationship between dam mechanical parameters and dam *** the process of back analysis,the initial samples of parameters were designed with uniform design ***,a transversely isotropic model of RCCD was established by *** *** this model,training samples of LSSVM model could be *** then,the complex nonlinear relationship between relative values of hydraulic components of dam displacements and mechanical parameters was ***,actual relative values of dam hydraulic components are isolated from the measured data of dam displacements by using *** inputting the isolated relative values into LSSVM model,the back analysis values of RCCD mechanical parameters can be *** example analysis showed that mechanical parameters obtained by the above-mentioned back analysis method are reasonable,and the back analysis method is feasible.

关键词： roller compacted concrete dam mechanical parameters back analysis

NEW METHOD OF SIMULATING CONCENTRATED DRAIN HOLES IN SEEPAGE CONTROL ANALYSIS

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 1999年第3期11卷 27-35页

作者： Zhan Mei li, Su bao yu , Liu Jun yong, Shen Zhen zhong {3. of water {3. and hydropower engineering, hohai university, nanjing 2.0098, P.R.China (Received Aug.1, 1998)

In this paper, based upon the basic solution of sink, the approximate solution of single drain hole in finite elements is derived by use of the superposition principle. Then, the theoretical solution is extended to the case of some drain holes in one finite element, and the method is used in seepage control analysis with quick convergence and high accuracy. On the other hand, if the positions of the drain holes are changed, only some control factors of drain holes are changed, but the finite element grid need not to be reformed. Therefore, the method is more suitable in optimal research of seepage control.

关键词： concentrated drain hole approximate solution seepage control optimal research

EXPERIMENTAL STUDY AND NUMERICAL SIMULATION OF FLUORIDE IN SAND

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2006年第6期18卷 748-751页

作者： ZHANG hong-mei SU bao-yu School of Resources and Safety engineering China University of Mining and Technology Beijing 100083China college Of water conservancy and {3. engineering Hohai University Nanjing 210098China

The transport and transformation of fluoride in sand were studied by using soil tank test under the condition of saturated water in this article. Based on the analysis of the laboratory experiments, the rules of fluorine transportation and transformation were simulated in sand by solving the advection-diffusion equation. Through comparison between computed results and observed data , it is shown that the established model and determined parameters could be used to simulate the fluoride transport in sand.

关键词： sand fluoride dynamic test numerical simulation

在线全文

学校读者我要写书评

暂无评论

南方典型灌区节水灌溉的减污效应

节水灌溉 2011年第8期 1-4页

作者：余金凤洪林江洪珊武汉大学水资源与水电工程科学国家重点实验室湖北武汉430072 广西水利水电职业技术学院广西南宁530023 武汉大学湖北武汉430027

由于其污染的严重性和控制的难度,农田氮磷流失造成的农业面源污染问题已经引起全球的关注。与传统灌溉相比,节水灌溉在减少农田氮磷流失方面具有一定优势。对湖北省漳河灌区2007-2008年试验资料进行分析,结果显示与传统灌溉相比较,节... 详细信息

由于其污染的严重性和控制的难度,农田氮磷流失造成的农业面源污染问题已经引起全球的关注。与传统灌溉相比,节水灌溉在减少农田氮磷流失方面具有一定优势。对湖北省漳河灌区2007-2008年试验资料进行分析,结果显示与传统灌溉相比较,节水灌溉能够节灌25%以上;排水量水稻减少45.0%,玉米减少11.6%,渗漏量水稻减少3..7%;氮肥利用率增加3.～5%,说明该地区实行节水灌溉可以在节水的同时,提高化肥利用率,降低氮磷流失量,减少对水环境的污染。

关键词：节水灌溉农田排水渗漏氮磷流失污染

在线全文

学校读者我要写书评

暂无评论

南水北调中线渠首前馈控制方案快速计算分析

中国农村水利水电 2024年第2期 129-137页

作者：张保航张召雷晓辉魏宏郁河北工程大学水利水电学院河北邯郸056038 河北工程大学河北省智慧水利重点实验室河北邯郸056038 中国水利水电科学研究院北京100038

明渠调水工程中为适时适量的满足下游用水需求,需要提前制定控制方案。前馈控制方案的设计往往较为复杂,且影响因素众多,调度人员难以快速做出决策。基于蓄量补偿法对南水北调中线工程刁河节制闸至十二里河节制闸段作前馈控制,基于蓄量... 详细信息

明渠调水工程中为适时适量的满足下游用水需求,需要提前制定控制方案。前馈控制方案的设计往往较为复杂,且影响因素众多,调度人员难以快速做出决策。基于蓄量补偿法对南水北调中线工程刁河节制闸至十二里河节制闸段作前馈控制,基于蓄量补偿计算结果,分析了初始流量、分水流量与前馈控制时间的关系,构建了单、双变量的前馈控制时间快速计算公式。探究了不同因素对蓄量补偿控制下游水位偏差的影响,得到初始流量、分水流量与下游水位最大偏差之间的函数关系式。针对工程运行中的极端工况,原蓄量补偿控制的下游水位偏差过大的问题,采用二次蓄量补偿规则对渠池进行前馈控制,有效减小了下游水位偏差。

关键词：明渠调水蓄量补偿法前馈控制快速计算公式二次蓄量补偿规则

双组分玻色-爱因斯坦凝聚体中PT对称势下的异步量子Kármán涡街

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

物理学报 2024年第11期73卷 37-45页

作者：邵凯花席忠红席保龙涂朴王青青马金萍赵茜石玉仁西北师范大学物理与电子工程学院兰州730070 甘肃民族师范学院物理与水电工程系合作747000 四川文理学院智能制造学院达州635000

数值研究了相混合态双组分玻色-爱因斯坦凝聚体(Bose-Einstein condensate,BEC)中PT (parity-time)对称势下的动力学.在障碍势不同的宽度和速度下发现了异步量子Kármán涡街、斜向漂移涡旋偶极子、V字形涡旋对、无规则量子湍流以及各... 详细信息

数值研究了相混合态双组分玻色-爱因斯坦凝聚体(Bose-Einstein condensate,BEC)中PT (parity-time)对称势下的动力学.在障碍势不同的宽度和速度下发现了异步量子Kármán涡街、斜向漂移涡旋偶极子、V字形涡旋对、无规则量子湍流以及各种尾迹的组合模式.研究了作用在移动障碍势上的拖拽力,分析了涡旋对产生的力学机理.在不同障碍势宽度和速度下,系统地模拟了异步量子Kármán涡街和其他尾迹模式的参数区域.同样分析了PT对称势中具有增益-损耗强度的虚部对异步量子Kármán涡街稳定性的影响.最后,提供了一个实现异步量子Kármán涡街的实验方案.

关键词：玻色-爱因斯坦凝聚体 Kármán涡街 PT对称势

维普期刊数据库博看期刊

Experimental Study of Fluorine Transport Rules in Unsaturated Stratified Soil

在线全文

学校读者我要写书评

暂无评论

Journal of China university of Mining and Technology 2007年第3期17卷 382-386页

作者： ZHANG hong-mei SU bao-yu LIU Peng-hua ZHANG Wei School of Resources ＆ Safety engineering China university of Mining ＆ Technology Beijing 100083 China college of water conservancy and {3. engineering hohai university nanjing Jiangsu 2.0098 China

With the aid of soil column test models,the transport rules of fluorine contaminants in unsaturated stratified soils are discussed. Curves of F-concentrations at different times and sites in the unsaturated stratified soil were ob-tained under conditions of continuous injection of fluoride contaminants and water. Based on the analysis of the actual observation data,the values between computed results and observed data were compared. It is shown that the chemical properties of fluorine ions are active. The migration process of fluorine ions in soils is complex. Because of the effect of adsorption and desorption,the curve of the fluorine ion breakthrough curve is not symmetric. Its concentration peak value at each measuring point gradually decays. The tail of the breakthrough curve is long and the process of leaching and purifying using water requires considerable time. Along with the release of OHˉ in the process of fluorine absorp-tion,the pH value of the soil solution changed from neutral to alkalinity during the test process. The first part of the breakthrough curve fitted better than the second part. The main reason is that fluorine does not always exist in the form of fluorinions in groundwater. Given the long test time,fluorinions possibly react with other ions in the soil solution to form complex water-soluble fluorine compounds. Only the retardation factor and source-sink term have been considered in our numerical model,which may leads to errors of computed values. But as a whole the migration rules of fluorine ions are basically correct,which indicates that the established numerical model can be used to simulate the transport rules of fluorine contaminants in unsaturated stratified soils.

关键词： fluorine unsaturated soil transport rules soil column test numerical simulation

土壤CO_(2)排放对微咸水与淡水交替灌溉的响应

在线全文

学校读者我要写书评

暂无评论

节水灌溉 2024年第8期 102-109页

作者：陈艺伟管瑶贺兴宏李会文王剑王育强范德宝塔里木大学水利与建筑工程学院新疆阿拉尔843300

为揭示微咸水与淡水交替灌溉模式对土壤CO_(2)排放通量变化规律的影响,研究极端干旱区棉田3.灌溉水质(矿化度分别为2、3.5 g/L)和3.不同配比咸淡水交替[微咸水∶淡水=1∶1(W1);微咸水∶淡水=1∶4(W2);微咸水∶淡水=1∶0(W3.]灌溉对土... 详细信息

为揭示微咸水与淡水交替灌溉模式对土壤CO_(2)排放通量变化规律的影响,研究极端干旱区棉田3.灌溉水质(矿化度分别为2、3.5 g/L)和3.不同配比咸淡水交替[微咸水∶淡水=1∶1(W1);微咸水∶淡水=1∶4(W2);微咸水∶淡水=1∶0(W3.]灌溉对土壤CO_(2)排放通量的影响。结果表明:①以2 g/L为对照,3.g/L微咸水与淡水交替灌溉处理CO_(2)累积排放通量减少了6.03.~7.19%;5 g/L微咸水与淡水交替灌溉处理CO_(2)累积排放通量减少了9.83.~10.15%;②在相同矿化度条件下,土壤CO_(2)累积排放通量为W2处理>W1处理>W3.理,淡水灌水量多的处理CO_(2)排放通量较大。③以2 g/L为对照,3.g/L和5 g/L处理产量平均提高了1.25%和3.64%,W1处理产量相较于W2、W3.理平均提高了24.02%和14.12%。随着灌溉水矿化度的增大,土壤CO_(2)排放通量减小,所有不同配比下矿化度为5 g/L的处理CO_(2)排放量均小于2、3.g/L的处理;在微咸水与淡水交替灌溉条件下,矿化度为3.g/L且微咸水∶淡水=1∶1的灌水处理,土壤CO_(2)排放通量降低且棉花产量最大,能够为合理利用微咸水及保护干旱区灌区农田生态环境提供理论依据。

关键词：咸淡水交替灌溉土壤CO_(2)排放通量

维普期刊数据库博看期刊