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端部效应对长初级双边直线感应电机影响研究
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作者 刘希军 魏麟 +1 位作者 朱新宇 高丽霞 《机电工程》 CAS 北大核心 2018年第2期170-174,共5页
针对变极矩直线感应电机极矩的变化,对端部效应亦产生影响,致使合成磁场畸变这一问题,分别采用电磁场理论分析方法和等效电路两种分析方法,根据直线感应电机磁场气隙磁通密度,以及直线感应电机等效电路,推导出了场理论及路理论直线感应... 针对变极矩直线感应电机极矩的变化,对端部效应亦产生影响,致使合成磁场畸变这一问题,分别采用电磁场理论分析方法和等效电路两种分析方法,根据直线感应电机磁场气隙磁通密度,以及直线感应电机等效电路,推导出了场理论及路理论直线感应电机端部效应参数方程,分析了入端衰减参数、出端衰减参数、行波波长等端部效应参数对电机气隙磁场的影响;对极矩变化型长初级双边直线感应电机进行了建模分析,分析了极矩变化对端部效应参数、电机气隙磁场影响。研究结果表明:极矩的变化对直线电机横向端部效应影响较小,对纵向端部效应影响较大,且随着极矩的增加,纵向端部效应影响逐渐减小。 展开更多
关键词 长初级双边直线感应电机 行波磁场 端部效应 极矩变化
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Ground roll attenuation using a time-frequency dependent polarization filter based on the S transform 被引量:6
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作者 谭玉阳 何川 +1 位作者 王艳冬 赵忠 《Applied Geophysics》 SCIE CSCD 2013年第3期279-294,358,共17页
The ground roll and body wave usually show significant differences in arrival time, frequency content, and polarization characteristics, and conventional polarization filters that operate in either the time or frequen... The ground roll and body wave usually show significant differences in arrival time, frequency content, and polarization characteristics, and conventional polarization filters that operate in either the time or frequency domain cannot consider all these elements. Therefore, we have developed a time-frequency dependent polarization filter based on the S transform to attenuate the ground roll in seismic records. Our approach adopts the complex coefficients of the S transform of the multi-component seismic data to estimate the local polarization attributes and utilizes the estimated attributes to construct the filter function. In this study, we select the S transform to design this polarization filter because its scalable window length can ensure the same number of cycles of a Fourier sinusoid, thereby rendering more precise estimation of local polarization attributes. The results of applying our approach in synthetic and real data examples demonstrate that the proposed polarization filter can effectively attenuate the ground roll and successfully preserve the body wave. 展开更多
关键词 Ground roll S transform spectral matrix polarization attributes polarization filter
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