We used computational fluid dynamics(CFD) and mode superposition method instead of the energy balance method to compute transmission line aeolian vibrations induced by the Karman vortex.Firstly,we obtained the wind po...We used computational fluid dynamics(CFD) and mode superposition method instead of the energy balance method to compute transmission line aeolian vibrations induced by the Karman vortex.Firstly,we obtained the wind power inputs using CFD theory.The result is effective for aeolian vibration analyses compared with the power which were measured in wind tunnel tests.Then a new aeolian excitation was derived using the wind power equivalent principle,and the aeolian vibration distribution along transmission lines and the wind power input obtained by CFD can be account.Secondly,we formulated the motion equation of a conductor-damper system and derived a semi-analytial solution using the mode superposition method.The Stockbridge-type dampers attached were simplified to the forces transmitted by the clamps.Finally,the semi-analytical solution can be solved by iterative methods.Taking a 1 000 kV Ultra High Voltage transmission line as an example,we analyzed the line with and without dampers by the semi-analytical solution.Compared with the results which were computed by the energy balance method,the semi-analytical solution is precise enogh for aeolian vibration analyses.Besides,we also analyzed the influence of damper position and quantity.展开更多
We propose a simple scheme to generate x-type four-charge entangled states by using SQUID-based charge qubits capacitively coupled to a transmission line resonator （TLR）. The coupling between the superconducting qub...We propose a simple scheme to generate x-type four-charge entangled states by using SQUID-based charge qubits capacitively coupled to a transmission line resonator （TLR）. The coupling between the superconducting qubit and the TLR can be effectively controlled by properly adjusting the control parameters of the charge qubit. The experimental feasibility of our scheme is also shown.展开更多
格库铁路青海段大部分处于偏远无人区,且区间无轨道电路,为检测断轨与减轻维护压力,设计了基于轨道电路原理的实时断轨检测系统。利用远距离无线电(Long Range Radio,LoRa)设计链式通信系统来传输报文,并进行理论指标验证;又在均匀传输...格库铁路青海段大部分处于偏远无人区,且区间无轨道电路,为检测断轨与减轻维护压力,设计了基于轨道电路原理的实时断轨检测系统。利用远距离无线电(Long Range Radio,LoRa)设计链式通信系统来传输报文,并进行理论指标验证;又在均匀传输线基础上得到轨道电路功率估计算式;随后,搭建信号发送系统,在室内利用模拟钢轨盘验证了使用功率估计区分断轨的可行性;最后,结合室内实验和链式通信系统搭建样机,现场测试验证了轨道电路功率估计算式的准确性。实验表明:利用轨道电路功率估计可有效、准确地完成断轨检测,室内和室外功率计算最小误差分别达1.06%和5.2%。相较于传统钢轨探伤方式,更适合在无人区非集中区段部署。展开更多
基金Funded by the National Natural Science Foundation of China (No.50878093)the State Grid Company of China under Grant No. [2007]413. This support is greatly appreciated.
文摘We used computational fluid dynamics(CFD) and mode superposition method instead of the energy balance method to compute transmission line aeolian vibrations induced by the Karman vortex.Firstly,we obtained the wind power inputs using CFD theory.The result is effective for aeolian vibration analyses compared with the power which were measured in wind tunnel tests.Then a new aeolian excitation was derived using the wind power equivalent principle,and the aeolian vibration distribution along transmission lines and the wind power input obtained by CFD can be account.Secondly,we formulated the motion equation of a conductor-damper system and derived a semi-analytial solution using the mode superposition method.The Stockbridge-type dampers attached were simplified to the forces transmitted by the clamps.Finally,the semi-analytical solution can be solved by iterative methods.Taking a 1 000 kV Ultra High Voltage transmission line as an example,we analyzed the line with and without dampers by the semi-analytical solution.Compared with the results which were computed by the energy balance method,the semi-analytical solution is precise enogh for aeolian vibration analyses.Besides,we also analyzed the influence of damper position and quantity.
基金supported by the National Natural Science Foundations of China (Grant Nos. 10947017/A05 and 11074190)the Science Foundation of the Key Laboratory of Novel Thin Film Solar Cells, China (Grant No. KF200912)the Graduates' Innovative Scientific Research Project of Zhejiang Province, China (Grant No. 2011831)
文摘We propose a simple scheme to generate x-type four-charge entangled states by using SQUID-based charge qubits capacitively coupled to a transmission line resonator （TLR）. The coupling between the superconducting qubit and the TLR can be effectively controlled by properly adjusting the control parameters of the charge qubit. The experimental feasibility of our scheme is also shown.
文摘格库铁路青海段大部分处于偏远无人区,且区间无轨道电路,为检测断轨与减轻维护压力,设计了基于轨道电路原理的实时断轨检测系统。利用远距离无线电(Long Range Radio,LoRa)设计链式通信系统来传输报文,并进行理论指标验证;又在均匀传输线基础上得到轨道电路功率估计算式;随后,搭建信号发送系统,在室内利用模拟钢轨盘验证了使用功率估计区分断轨的可行性;最后,结合室内实验和链式通信系统搭建样机,现场测试验证了轨道电路功率估计算式的准确性。实验表明:利用轨道电路功率估计可有效、准确地完成断轨检测,室内和室外功率计算最小误差分别达1.06%和5.2%。相较于传统钢轨探伤方式,更适合在无人区非集中区段部署。
