Dynamic responses of a carriage under excitation with the German high-speed low-interference track spectrum together with the air pressure pulse generated as high-speed trains passing each other are investigated with ...Dynamic responses of a carriage under excitation with the German high-speed low-interference track spectrum together with the air pressure pulse generated as high-speed trains passing each other are investigated with a multi-body dynamics method.The variations of degrees of freedom（DOFs：horizontal movement,roll angle,and yaw angle）,the lateral wheel-rail force,the derailment coefficient and the rate of wheel load reduction with time when two carriages meet in open air are obtained and compared with the results of a single train travelling at specifie speeds.Results show that the rate of wheel load reduction increases with the increase of train speed and meets some safety standard at a certain speed,but exceeding the value of the rate of wheel load reduction does not necessarily mean derailment.The evaluation standard of the rate of wheel load reduction is somewhat conservative and may be loosened.The pressure pulse has significan effects on the train DOFs,and the evaluations of these safety indexes are strongly suggested in practice.The pressure pulse has a limited effect on the derailment coefficien and the lateral wheel-rail force,and,thus,their further evaluations may be not necessary.展开更多
A hardware platform using broadband antenna,oscilloscope,and spectrum analyzer is designed to receive radio frequency(RF)signals from electromagnetic radiation leakage of computers in the office environment.The proces...A hardware platform using broadband antenna,oscilloscope,and spectrum analyzer is designed to receive radio frequency(RF)signals from electromagnetic radiation leakage of computers in the office environment.The process of receiving and the processing techniques have also been given.Then,the software radio-based computing models and software algorithms are proposed to demodulate and decode the RF signals.An experimental result shows that the text information can be recovered from electromagnetic(EM)leakage wave of computer by this interception system.This architecture not only reduces the cost of the system’s hardware but also makes interception more flexible.The innovation points of this paper are recovering the video information in EM leakage wave of computers in an ordinary office environment based on public equipments and proposing the process of receiving processing techniques that only use the software radiobased computing models and software algorithms.展开更多
基金the National Basic Research Program of China (973 program,Grant 2011CB711100)the National Natural Science Foundation of China (Project No.11372307)the Chinese Academy of Sciences (Grant KJCX2-EW-L03)
文摘Dynamic responses of a carriage under excitation with the German high-speed low-interference track spectrum together with the air pressure pulse generated as high-speed trains passing each other are investigated with a multi-body dynamics method.The variations of degrees of freedom（DOFs：horizontal movement,roll angle,and yaw angle）,the lateral wheel-rail force,the derailment coefficient and the rate of wheel load reduction with time when two carriages meet in open air are obtained and compared with the results of a single train travelling at specifie speeds.Results show that the rate of wheel load reduction increases with the increase of train speed and meets some safety standard at a certain speed,but exceeding the value of the rate of wheel load reduction does not necessarily mean derailment.The evaluation standard of the rate of wheel load reduction is somewhat conservative and may be loosened.The pressure pulse has significan effects on the train DOFs,and the evaluations of these safety indexes are strongly suggested in practice.The pressure pulse has a limited effect on the derailment coefficien and the lateral wheel-rail force,and,thus,their further evaluations may be not necessary.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.60871081,60671055,and 60771060)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Nos.20070013002 and 20070013004).
文摘A hardware platform using broadband antenna,oscilloscope,and spectrum analyzer is designed to receive radio frequency(RF)signals from electromagnetic radiation leakage of computers in the office environment.The process of receiving and the processing techniques have also been given.Then,the software radio-based computing models and software algorithms are proposed to demodulate and decode the RF signals.An experimental result shows that the text information can be recovered from electromagnetic(EM)leakage wave of computer by this interception system.This architecture not only reduces the cost of the system’s hardware but also makes interception more flexible.The innovation points of this paper are recovering the video information in EM leakage wave of computers in an ordinary office environment based on public equipments and proposing the process of receiving processing techniques that only use the software radiobased computing models and software algorithms.
