共查询到20条相似文献,搜索用时 203 毫秒
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以某多层框架商业建筑为例,该建筑结构上存在扭转不规则、平面凹凸不规则、楼板局部不连续、穿层柱、平面超长等多项超限不规则,属于超限多层结构。对薄弱部位及超限项进行了楼板应力分析、穿层柱屈曲稳定性分析及整体模型弹性时程分析,并通过采取多项结构加强措施,解决了结构薄弱问题,保证了结构的安全性。 相似文献
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对液压多斗挖土机液压系统的原理进行介绍,详细阐述了液压泵、液压阀和液压缸的结构及常见故障,介绍了多斗挖土机液压系统的故障处理方法,以便多斗挖土机在维修后尽量少出故障。 相似文献
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地下工程超长结构抗裂防渗混凝土施工 总被引:3,自引:0,他引:3
北京西客站主站房及综合楼基础类型多、埋深差异大、地基承载力不均匀、区段平均超长,为解决不均匀沉降及控制温度收缩变形,防止混凝土开裂而采取了多项措施,设置后浇带及工艺缝,根据现场不同施工条件,进行多配比UEA补偿收缩混凝土施工;重点抓好变形缝的施工等,取得了良好效果。/ 相似文献
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本文介绍了多层多跨有粘结部分预应力框架的设计构思,应变协调分析,抗裂及挠度试验算等内容,首次提出多跨预应力框架分段锚固新方法,同时也提出了预应力框架设计的某些构造措施。 相似文献
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多联式空调机组在高速公路服务区工程中应用 总被引:1,自引:0,他引:1
简单介绍了多联式空调机组(VRF)的组成及工作原理,结合高速公路服务区的功能特点,分析了VRF空调系统比传统集中空调系统的优越性,通过一个高速公路服务区多联式空调系统的应用实例,介绍了VRF系统的工程设计方法及注意事项。 相似文献
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利用单片机的多路远距离遥控开关装置来制作水位显示,它由遥控器(发射器件)和开关盒(接收器)两部分组成,该遥控器可控制多路开关盒实现水位显示。 相似文献
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The independent metering system is an alternative to the conventional valve control system by decoupling the meter-in and meter-out orifices. With a number of features such as flow recuperation or regeneration, and simultaneous control of speed and pressure, the energy saving performance can be improved. Nevertheless, independent metering systems make the control more complex. The current control design focused on the two-level controller: mode switch in upper level, and velocity and pressure control in lower level. However, pump control is seldom considered and the coordinate control of pump and valves briefly couples electronic load sensing (ELS) with the two-level controller. The contribution of this paper is to design a three-level controller to improve the energy efficiency. The upper level determines the operating mode in terms of the current system states and desired motion trajectory. The lower level contains the meter-out flow/pressure valve control and the open-loop displacement pump control. A coordinate level is added to incorporate the pump control into the valve control. By the coordinate control of the pump and valves, the meter-in valve opens maximally and the pressure losses across the valves can be minimized. The problems caused by the maximal opening of the meter-in valve are described and then solved by three parts: pressure matching, configuration of flow/pressure valve control and damping compensator. The proposed controller is applied to a mini-excavator. The experimental results of boom and arm motions show that the three-level controller is able to address dual objectives of energy saving and control performance improvement. 相似文献
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在项目建设过程中普遍存在项目前期工作薄弱、项目管理水平尚待提高.项目投资控制必须贯穿于项目建设全过程,工程造价才能得到合理确定和有效控制. 相似文献
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现在城市排水系统的规划和运营管理一般不考虑城市下游受纳水体变化的影响,这也是国内城市内涝频发的原因之一。目前,越来越多的城市应用模型来应对城市内涝,模型中受纳水体的水位一直以来都是利用经验设定一个恒定值。本文利用ANN(人工神经网络)技术,以城市上游观测站的实测水位为输入,以城市未来某时段的水位为目标选择合理的参数,建立了预测河流水位模型。利用更准确的动态预测值代替恒定值,可以提高城市排水系统水力模型的精度。选择某地区水位站的资料,对预报模型进行了检验,结果表明,在合理选择输入层数据和预测时间段的条件下,可以取得很好的预报结果。 相似文献
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现有工程项目交易方式的选择通常考虑项目管理层面的因素,而忽略了项目治理层面相关因素的影响,这导致BT 模式下工程项目交易效率较低,成为制约BT 模式在我国城市轨道交通项目中推行的关键因素之一。为此,本文引入项目治理理论,提出应根据BT 项目契约中的项目控制权强弱及与之匹配的风险分担的有效性划分出强BT、标准BT、弱BT 三种项目交易模式,给出了按照项目控制权与风险分担相匹配的BT 模式选择过程,并通过案例研究分析了这三种模式的运行效果,为城市轨道交通项目BT 模式创新和优化提供了依据。 相似文献
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详述了如何通过VB编程、Access数据库技术以及局域网在成本材料控制中的结合使用,得以对大量数据信息的自动查询处理,实现了项目施工在成本管理上的实时有效控制,从而提高成本控制水平。 相似文献
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E vry WATER DISTRIBUTION system has an economic optimum level of leakage. To maintain that optimum level of leakage there is a corresponding optimum level of leakage control activity.
Despite much work on this subject, particularly in recent years with publication of DoE Report No. 261 , many undertakers remain unclear about their economic optimum leakage level and how much effort is required to maintain that level.
This paper describes development of an economic model which attempts to quantify optimum leakage through measurement of parameters which should be readily available or obtainable.
The model was originally developed specifically for routine sounding. However, extension of the basic principles allows development of a general optimization theory. The paper then shows how the theory can be applied to optimization of district metering 相似文献
Despite much work on this subject, particularly in recent years with publication of DoE Report No. 26
This paper describes development of an economic model which attempts to quantify optimum leakage through measurement of parameters which should be readily available or obtainable.
The model was originally developed specifically for routine sounding. However, extension of the basic principles allows development of a general optimization theory. The paper then shows how the theory can be applied to optimization of district metering 相似文献