As for the Domino effect dv/dt and electromagnetic interference during the rapid switching course of single-chip switching power supply,this article firstly analyzes electromagnetic interference source,and then diagno...As for the Domino effect dv/dt and electromagnetic interference during the rapid switching course of single-chip switching power supply,this article firstly analyzes electromagnetic interference source,and then diagnoses the essential interaction relationship between interference and switching activity based on the timely and area measured waveform,analyzes and studies the production mechanism and coupling path of interference mode,and sets up circuit model according to the features of transverse mode interference and common mode interference.Put forward different suppression methods finally.展开更多
When measuring the surface subsidence of unstable areas such as railroad beds and large construction fields, it is not practical to always find stable positions to install measurement instruments. Yet installing those...When measuring the surface subsidence of unstable areas such as railroad beds and large construction fields, it is not practical to always find stable positions to install measurement instruments. Yet installing those instruments in unstable positions will cause measurement errors or even the complete failure of long-term subsidence surveillance. In this paper, the innovative concept and its method of "displacement-relay videometrics" are proposed. With the method, a double-headed camera is designed, and two constraints, the "fixation constraint" and the "homologous constraint", are established to construct the displacement-relay measurement equations, which can concurrently give the subsidence of the points to be measured and the positions where the cameras are fixed. The method and its measurement system are thus capable of automatically measuring the surface subsidence under the condition that the cameras are mounted on unstable locations over long durations. Therefore, the method has the broad prospect of undertaking automatic, long-term and continuous measurement for surface subsidence in engineering projects such as railroad beds, bridges and the ground beds of tall buildings. The proposed method opens a new area that cameras can be mounted on unstable platform to make high accuracy measurements, which is of great significance for applications.展开更多
基金Tianjin Natunal science Foundation of China(No:05YFSYSF033)
文摘As for the Domino effect dv/dt and electromagnetic interference during the rapid switching course of single-chip switching power supply,this article firstly analyzes electromagnetic interference source,and then diagnoses the essential interaction relationship between interference and switching activity based on the timely and area measured waveform,analyzes and studies the production mechanism and coupling path of interference mode,and sets up circuit model according to the features of transverse mode interference and common mode interference.Put forward different suppression methods finally.
基金supported by the National Natural Science Foundation of China(Grant Nos.11332012 and 11172323)
文摘When measuring the surface subsidence of unstable areas such as railroad beds and large construction fields, it is not practical to always find stable positions to install measurement instruments. Yet installing those instruments in unstable positions will cause measurement errors or even the complete failure of long-term subsidence surveillance. In this paper, the innovative concept and its method of "displacement-relay videometrics" are proposed. With the method, a double-headed camera is designed, and two constraints, the "fixation constraint" and the "homologous constraint", are established to construct the displacement-relay measurement equations, which can concurrently give the subsidence of the points to be measured and the positions where the cameras are fixed. The method and its measurement system are thus capable of automatically measuring the surface subsidence under the condition that the cameras are mounted on unstable locations over long durations. Therefore, the method has the broad prospect of undertaking automatic, long-term and continuous measurement for surface subsidence in engineering projects such as railroad beds, bridges and the ground beds of tall buildings. The proposed method opens a new area that cameras can be mounted on unstable platform to make high accuracy measurements, which is of great significance for applications.
