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Geophysical methods for the study of sedimentary cycles 被引量:10
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作者 Xu Jingling Liu Luofu +2 位作者 Wang Guiwen Shen Jinsong Zhang Chunhua 《Petroleum Science》 SCIE CAS CSCD 2009年第3期259-265,共7页
We present the wavelet depth-frequency analysis and variable-scale frequency cycle analysis methods to study sedimentary cycles. The spectrum analysis, variable-scale frequency cycle analysis, and wavelet depth-freque... We present the wavelet depth-frequency analysis and variable-scale frequency cycle analysis methods to study sedimentary cycles. The spectrum analysis, variable-scale frequency cycle analysis, and wavelet depth-frequency analysis methods are mainly discussed to distinguish sedimentary cycles of different levels. The spectrum analysis method established the relationship between the spectrum characteristics and the thickness and number of sedimentary cycles. Both the variable-scale frequency cycle analysis and the wavelet depth-frequency analysis are based on the wavelet transform. The variable-scale frequency cycle analysis is used to obtain the relationship between the periodic changes of frequency in different scales and sedimentary cycles, and the wavelet depth-frequency analysis is used to obtain the relationship between migration changes of frequency energy clusters and sedimentary cycles. We designed a soft-ware system to process actual logging data from the Changqing Oilfield to analyze the sedimentary cycles, which verified the effectiveness of the three methods, and good results were obtained. 展开更多
关键词 Sedimentary cycles spectrum analysis wavelet depth-frequency analysis variable-scale frequency cycle analysis
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Study on fuzzy control of dynamic equalization based on state prediction
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作者 程树康 Tian +2 位作者 Likun Kong Zhiguo 《High Technology Letters》 EI CAS 2008年第4期399-404,共6页
A new method of using dynamic equalization technology to realize the maximum energy storage utilization was presented to overcome the influence of the disaccord among units of series super capacitor (SC) bank and en... A new method of using dynamic equalization technology to realize the maximum energy storage utilization was presented to overcome the influence of the disaccord among units of series super capacitor (SC) bank and ensure that the units could work safely. By considering in combination with the high specific power, low working voltage, wide voltage working range and noulinear external characteristics, we present constant duty ratio pulse frequency modulation mode and fuzzy control method based on state prediction in the active equalization circuit and accomplish the software and hardware design for the equalization system. The simulation analysis and experiment results of constant current muhi-cycle and variable current multi-cycle charge-discharge process verify the validity of the design. 展开更多
关键词 dynamic equalization series supercapacitor bank fuzzy control pulse frequency modulation with constant cycle ratio state prediction
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