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密集型谐波检测的压缩采样方法 被引量:8
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作者 袁博 王莹 +3 位作者 邵华 王颖 贺春光 杨挺 《电力系统自动化》 EI CSCD 北大核心 2016年第20期54-61,167,共9页
压缩采样已成为电力系统中复杂谐波畸变信号实时采集和密集检测的发展趋势。文中针对谐波和间谐波检测,提出一种新型压缩采样检测方法。分析得到稀疏度的相关定理和推论,提出多重提取梯度追踪(MEGP)算法,提升谐波分量、特别是间谐波分... 压缩采样已成为电力系统中复杂谐波畸变信号实时采集和密集检测的发展趋势。文中针对谐波和间谐波检测,提出一种新型压缩采样检测方法。分析得到稀疏度的相关定理和推论,提出多重提取梯度追踪(MEGP)算法,提升谐波分量、特别是间谐波分量的检测精度。考虑频谱泄漏影响,构造窗稀疏测量(WSM)矩阵,生成简单且对所有分量有效。实验表明,MEGP算法至少可将频率、幅值、相位检测精度分别提升0.000 53Hz、0.011 2个百分点和0.071°,WSM矩阵则可将信噪比提升约30dB。所提压缩采样检测方法对频率、幅值和相位的检测误差在0.004 03 Hz、0.001 73%和0.037 221°以内,满足国家标准要求。 展开更多
关键词 压缩采样 谐波检测 多重提取梯度追踪算法 窗稀疏测量
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视频高压缩技术发展中的格式一览
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作者 解放 《实用影音技术》 2003年第9期70-75,共6页
当今社会正处于信息爆炸与计算机急速渗透各领域的新鼎盛时代,涵盖图像、声音、文本等的多媒体信息无间断地在人们的社会与家庭生活中穿梭往来.
关键词 视频高压缩技术 编码格式 megp WMV9 WM9 VP5 Divx5
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Mechanically exfoliated graphite paper with layered microstructures for enhancing flexible electrochemical energy storage
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作者 Haihan Zhou Yuqin Liu +1 位作者 Mengyao Ren Hua-Jin Zhai 《Inorganic Chemistry Frontiers》 2022年第9期1920-1930,共11页
Superior electrochemical properties and high flexibility are two crucial requirements and challenges for electrochemical capacitors(ECs)applied in flexible and wearable electronics.Here a low-cost and scalable method ... Superior electrochemical properties and high flexibility are two crucial requirements and challenges for electrochemical capacitors(ECs)applied in flexible and wearable electronics.Here a low-cost and scalable method is proposed for the fabrication of mechanically exfoliated graphite paper(MEGP),which shows unique layered microstructures.The MEGP is subsequently used as a current collector to directly load multi-walled carbon nanotube@polypyrrole(MWCNT@PPy)core–shell hybrids as active materials,by electro-codeposition.The resultant MEGP/MWCNT@PPy electrodes demonstrate substantially enhanced electrochemical properties compared to GP/MWCNT@PPy,owing to the 3D interface constructed between layered MEGP and MWCNT@PPy.The symmetrical EC assembled using MEGP/MWCNT@PPy electrodes achieves an areal capacitance of 101.5 mF cm^(−2) at a current density of 0.5 mA cm^(−2),and an ideal rate capability.It also shows an electrochemical stability of 87.1%after 10000 cycles,and retains 95.1%of the initial capacitance after enduring harsh mechanical deformation 400 times.These results indicate that the EC device has superior electrochemical properties and high flexibility with great potential for utilization in flexible and wearable electronic devices.The MEGP we have developed not only ensures the high flexibility of the device,but also boosts its electrochemical performance. 展开更多
关键词 active materialsby layered microstructuresthe mechanically exfoliated graphite paper layered microstructures electrochemical capacitors ecs applied mechanically exfoliated graphite paper megp which flexible wearable electronicshere current collector
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