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液压挖掘机合流工况多路阀内流阻力的分析 被引量:3
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作者 冀宏 秦娟娟 +1 位作者 刘新强 陆海娇 《液压与气动》 北大核心 2013年第9期41-45,共5页
分析了挖掘机负流量变量系统的工作原理,建立了负流量-恒功率变量控制的动臂回路液压系统AMESim模型,获得了双泵合流系统动态特性,进而利用FLUENT计算多路阀内流场。结果表明:快速提臂双泵合流时多路阀内流动阻力达2.6 MPa,阻力主要发... 分析了挖掘机负流量变量系统的工作原理,建立了负流量-恒功率变量控制的动臂回路液压系统AMESim模型,获得了双泵合流系统动态特性,进而利用FLUENT计算多路阀内流场。结果表明:快速提臂双泵合流时多路阀内流动阻力达2.6 MPa,阻力主要发生在合流窗口、节流口、直弯流道处。发现合流窗口处高速液流冲击其后阀芯及阀腔,高速液流交汇增大了流动阻力,改变了阀腔内压力分布使阀芯受到较大侧向力的情况。 展开更多
关键词 液压挖掘机 多路阀 流量-恒功率控制 双泵合流 流动阻力
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无人值守的电加热监测换热器的设计与实现
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作者 梅英杰 宁媛 《内蒙古科技与经济》 2019年第11期80-81,共2页
本次设计的系统是采用西门子Smart700触摸屏,加热方式为电加热式的监测换热系统。本系统能够对现场数据进行实时有效采集,并能保留历史数据,在控制结构上采用分布式控制,使得测量更加合理。流量和功率的控制采用模糊PID控制,保证控制的... 本次设计的系统是采用西门子Smart700触摸屏,加热方式为电加热式的监测换热系统。本系统能够对现场数据进行实时有效采集,并能保留历史数据,在控制结构上采用分布式控制,使得测量更加合理。流量和功率的控制采用模糊PID控制,保证控制的稳定精确。整体上而言,良好的自动控制,以及较好的人机交互和较强的抗干扰能力,使得该监测换热器的特点鲜明。同时本系统还实现了无线远程通讯,使得换热器的使用更加人性化。 展开更多
关键词 电加热 流量功率控制 模糊PID 远程通讯
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The New Architecture with Time-Spatial Consistency for 5G Networks 被引量:3
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作者 SUN Zhennian XU Xu +3 位作者 CHAI Xiaomeng ZHANG Tianyu TIAN Lin ZHANG Zhongshan 《China Communications》 SCIE CSCD 2016年第1期68-79,共12页
While operators have started deploying fourth generation(4G) wireless communication systems,which could provide up to1 Gbps downlink peak data rate,the improved system capacity is still insufficient to meet the drasti... While operators have started deploying fourth generation(4G) wireless communication systems,which could provide up to1 Gbps downlink peak data rate,the improved system capacity is still insufficient to meet the drastically increasing demand of mobile users over the next decade.The main causes of the above-mentioned phenomenon include the following two aspects:1) the growth rate of the network capacity is far below that of user's demand,and 2) the relatively deterministic wireless access network(WAN) architecture in the existing systems cannot accommodate the prominent increase of mobile traffic with space-time domain dynamics.In order to address the above-mentioned challenges,we investigate the time-spatial consistency architecture for the future WAN,whilst emphasizing the critical roles of some spectral-efficient techniques such as Massive multiple-input multiple-output(MIMO),full-duplex(FD)operation and heterogeneous networks(HetNets).Furthermore,the energy efficiency(EE)of the HetNets under the proposed architecture is also evaluated,showing that the proposed user-selected uplink power control algorithm outperforms the traditional stochastic-scheduling strategy in terms of both capacity and EE in a two-tier HetNet.The other critical issues,including the tidal effect,the temporal failure owing to the instantaneously increased traffic,and the network wide load-balancing problem,etc.,are also anticipated to be addressed in the proposed architecture.(Abstract) 展开更多
关键词 wireless access network spectral efficiency energy efficiency super base station heterogeneous network
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