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钢结构磁性无损检测中的几个基本技术问题 被引量:6
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作者 王威 章红梅 +1 位作者 张富文 周颖 《结构工程师》 2008年第6期120-127,共8页
磁检测技术是一种有待发展的新技术。与其他各类有损和无损检测方法相比较,铁磁类材料的磁性变化更易于检测和实现在线实时监测。因此,基于磁效应的钢结构及构件无损检测技术凸显出它的优越性来。主要讨论了钢结构磁性无损检测中的几个... 磁检测技术是一种有待发展的新技术。与其他各类有损和无损检测方法相比较,铁磁类材料的磁性变化更易于检测和实现在线实时监测。因此,基于磁效应的钢结构及构件无损检测技术凸显出它的优越性来。主要讨论了钢结构磁性无损检测中的几个基本技术问题:磁化技术,磁信号测量技术,磁信号处理技术,磁信号的频域数字滤波,磁检测装置抗干扰技术,退磁技术等。 展开更多
关键词 磁信号测量 信号处理 信号的频域数字滤波 抗干扰 退
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A hybrid stepping motor system with dual CPU
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作者 高晗璎 赵克 孙力 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2004年第4期382-386,共5页
An indirect method of measuring the rotor position based on the magnetic reluctance variation is presented in the paper. A single-chip microprocessor 80C196KC is utilized to compensate the phase shift produced by the ... An indirect method of measuring the rotor position based on the magnetic reluctance variation is presented in the paper. A single-chip microprocessor 80C196KC is utilized to compensate the phase shift produced by the process of position signals. At the same time, a DSP (Data Signal Processor) unit is used to realize the speed and current closed-loops of the hybrid stepping motor system. At last, experimental results show the control system has excellent static and dynamic characteristics. 展开更多
关键词 closed-loop control indirect measurement hybrid stepping motor
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High-precision time and frequency measurement method combining time-space conversion and different frequency phase detection 被引量:4
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作者 DU BaoQiang WANG YanFeng +3 位作者 CUI GuangZhao GUO ShuTing DONG ShaoFeng LIU Dan 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第11期2110-2115,共6页
According to the time&space conversion relations and different frequency phase detection principle,an ultra-high precision time&frequency measurement method is proposed in this paper.The higher accuracy and st... According to the time&space conversion relations and different frequency phase detection principle,an ultra-high precision time&frequency measurement method is proposed in this paper.The higher accuracy and stability of the speed of light and electromagnetic signals during the transmission in space or a specific medium enable the measurement of short time interval which uses the coincidence detection of signal’s transmission delay in length.The measurement precision better than 10 picoseconds can be easily obtained.The method develops the length vernier utilizing the stability of signal’s transmission delay,minimizes the fuzzy region of phase coincidence between the standard frequency signal and the measured signal,approaches the best phase coincidences and therefore improves the measurement precision which is higher than the precision provided by the traditional methods based on frequency processing.Besides,the method costs less than the traditional methods and can also solve the problem of the measurement of super-high frequency.Experimental results show the method can improve the measurement precision to 10 12/s in the time&frequency domain. 展开更多
关键词 time and space conversion delay-time phase shift different phase coincidence detection group phase difference
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