共查询到20条相似文献，搜索用时 312 毫秒
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在正断层引起的地面永久性大变形作用下,埋地管线可能会发生拉伸、剪切等形式的强度破坏,亦可能在局部受压区发生屈曲破坏。利用ABAQUS有限元分析软件,建立穿越正断层埋地管线的空间有限元分析模型,采用非线性接触分析方法模拟正断层引起的地表永久性大变形作用下管线-土体间的相互作用,分析了不同管径、跨越角对管线破坏模式的影响。依据算例分析可知:小口径埋地管线易发生拉伸强度破坏,大口径薄壁管线易发生屈曲失效,口径0.65 m是管线从发生强度破坏到发生屈曲破坏的临界值;当跨越角大于90°时,角度越大越易发生屈曲失效,跨越角为100°是埋地管线发生强度破坏与屈曲失效的分界点。 相似文献
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谱聚类在给水管网分区优化中的应用 总被引：2，自引：0，他引：2
利用图划分技术和图论算法实现给水管网分区。根据给水管网分析,确定分区数量,建立权重邻接矩阵并计算图拉普拉斯矩阵及其特征向量,通过多路图划分对隐藏在特征向量中的聚类信息进行数据挖掘,采用遗传算法和K均值方法实现最佳节点聚类。利用PageRank和最短路径算法确定水表和阀门位置,最终实现给水管网优化分区。实际给水管网模型分区实例表明所提方法在给水管网分区的有效性。 相似文献
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近年来随着膜下滴灌技术的大面积推广,棉花灌溉管网模式已形成了各自不同的滴灌模式,人们都在探究最经济最便于管理的管网模式。目前北疆几乎有80%的团场还在延用最初的滴灌系统模式;而南疆则不同,逐渐发展成支管 毛管或双支管 毛管的灌溉管网模式。现对不同的管网模式进行对比和分析。 相似文献
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地膜糜子节水补灌技术研究 总被引：2，自引：0，他引：2
试验对地膜糜子的最佳供水时期、供水量和节水灌溉材料进行了比较分析，结果表明，地膜糜子的最佳供水时期为抽穗期，适宜供水量为30mm，供水材料以渗灌最为节水。 相似文献
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农村集中供水管理存在的问题及改革建议 总被引：3，自引：1，他引：2
对湖北省荆州市8个县市区农村集中供水厂抽样调查显示,乡镇集中供水厂设施不完善,出厂水和使用自来水农户的生活用水水样均有1-3项指标超过国家规定标准,集中供水管理十分混乱,饮水安全存在较大不确定性。制定农村集中供水管理的法规,明确农村安全饮水的公益事业性质,明确地方政府在农村饮水安全中的责任,明确供水工程折旧提留费用管理办法,明确农村饮水安全管理责任追究办法,才能确保农村集中供水安全长效发展。 相似文献
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不同育苗方式对烟株生长发育的影响 总被引：1，自引：0，他引：1
为探索烤烟最佳育苗模式，试验研究了不同育苗方式对烟株生长发育的影响，结果表明：水床供水有利于烟株生长，其烟苗根茎叶干物质结累均比从上往下供水的处理好；间断供水的漂浮苗移栽大田后，其初烤烟叶经济性状比连续供水的漂浮苗更高，喷淋方式的漂浮苗移栽后经济性状不如连续供水的漂浮苗，说明育苗过程中，适当控制水分有利于烟株生长发育。 相似文献
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Pressure-Dependent Analysis of Water Supply Network Damaged by Earthquake Based on Emitter Model 总被引：2，自引：0，他引：2
When the water supply network suffered earthquake damages, pipeline leaks and bursts may occur. In the period in post-earthquake emergency rescue and repair, the network is supplying water with additional outflow of damages (leaks and breaks), which result in pressure deficient. According to the frictional head loss along the break pipeline, a model with additional emitter at the endpoint of the disconnect pipeline was proposed to simulate the break, which simplifies the modeling of breaks. The pressure-dependent demand relationship was adopted in the process of pressure-deficient hydraulic simulation to avoid node negative pressure. Meanwhile a backtracking and line search procedure was utilized to control the iteration step of pipeline network nonlinear equations, which ensure the global convergence of the hydraulic simulation. The effectiveness of the proposed method was verified by a case study. 相似文献
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It is helpful for energy efftciency to use distributed pumps instead of valves to regulate hydraulic balance in a district heating system (DHS). A new scheme of distributed pump-system is presented based on performance comparison of hydraulic regime and power saving of single-heat-source dendritic pipeline networks with regulating valves and/or distributed pumps. Supposing that the new scheme was employed in multi-sources looped-pipe network, theoretical analysis and case study were carried out to evaluate off-design performances including hydraulic self-regulation, supply water temperature stability and power-saving potential. The results indicated that the proposed scheme would contribute to minimizing power consumption, retarding water temperature change, and would be convenient to adjust the quality and quantity independently in the looped-pipe heat supply networks. 相似文献
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Zhong Jingxiao 《保鲜与加工》1989,(4)
This paper introduces the metod of optimal design of municipal water distribution,The main points are the theory,mathematical model,program frame figure and example in practice of the optimal method of hydraulics.The
program is applicable to the design and calculation of the pipe network in a city. It gives a simple and convenient calculation method for multiple-scheme design and scheme cmparison of water supply system. 相似文献
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Water supply in small towns is one of the important components of the small towns' economy and society development.Based on the actual condition of water supply system,this paper analyzes the problems existed in water supply system of small towns,such as gradually polluted sources,imperfect water supply facilities,smaller scales,unreasonable quantity and so on.In addition,the corresponding measures are put forward to guarantee water supply system develop speed in small towns.Those countermeasures are launching sources protection work to guarantee the drinking water safety according to the character of the small town,then adopts reasonable water supply style,chooses economy water processing method,optimizes water network system construction;selects reasonable quantity consumption quota,and carries out gradually the regional water supply mode in conditional small towns. 相似文献
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According to the analysis of technology and economy about the gas supply with the medium pressure in gas pipeline network of urban gas transmission and distribution system,a more economical and feasible pressure value is obtained. 相似文献
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A quantum self organizing feature map neural network (QSOM) method is introduced for water quality prediction in activated sludge wastewater treatment processes which includes uncertainty of microbial activity and complexity of biochemical reactions and strong lagging of parameters. This approach quantizes the inlet water quality data corresponding outlet water in abnormal state and makes the quantized data sample as the input of QSOM. The correlation coefficient of the quantum inputs and its weights are calculated as the best inputs matching of network by using quantum gates to update the weights in learning the rules. The experiments illustrate the efficiency of this prediction approach by using operational data of Chongqing Jiguanshi wastewater treatment plant. 相似文献
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The authors definitely make out the concept of loop main pipeline, supplying main pipeline and ramiform branch line, as well as the order of their hydraulic calculation. Then they puts forward the principia of how to study out the direction of loop main pipeline and presents the method of making flux initial distribution. The matrix of loop main pipeline hydraulic square dispersion is set up. The node referenced pressure is defined and the equation of how to calculate it is deduced. A software is developed to calculate the loop main pipeline hydraulic square dispersion. The method of calculating ramiform branch margin impetus is given. 相似文献
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Based on the reactive surplus of Chongqing 220 kV main electric power network under low water and low load, and on state of higher system voltage, a thorough research is done on voltage and reactive power of the system power network by means of calculation,analysis and experiments. A main network calculating equivalence model of power network in Chongqing is constructed. And reactive power optimizing calculation is figured out on the Chongqing power network on condition that the loss minimum of the active power network is object function. Several optimizing compensatory schemes are put forward. Based on the calculation result and the analysis of all schemes, the most reasonable and feasible optimizing scheme could be achieved. Meanwhile, the feasibility that the system voltage could be adjusted when generator operating under excitation was demonstrated. According to the experience of under-excitation operation of the same type units , it decreases the system voltage, improves Chongqing power network running performance, and strengthens the coordination and stabilization of system. 相似文献
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A Comparison of Four Methods of Water Quality Assessment 总被引：2，自引：0，他引：2
In this paper, a back propagation network, a Hopfield network, Fuzzy comprehensive index method and classification of gray are compared in application for water quality assessment. The comparison result shows that the BP network is the best one of these four methods. 相似文献