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针对幅相交织变化信号的过零点检测算法
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作者 王贺磊 李猷民 +2 位作者 姜建平 王尊贤 武守远 《电工技术》 2021年第3期24-26,30,共4页
为应对电气量在暂态过程中相位和幅值交织突变现象,提高过零点检测的准确性,提出了快速过零点检测算法。该算法在电气量通过窄带滤波器前进行归一化计算,通过检测算法和域值判断计算过零时刻并消除零点偏移和抖动现象,得到正负过零时刻... 为应对电气量在暂态过程中相位和幅值交织突变现象,提高过零点检测的准确性,提出了快速过零点检测算法。该算法在电气量通过窄带滤波器前进行归一化计算,通过检测算法和域值判断计算过零时刻并消除零点偏移和抖动现象,得到正负过零时刻及其相位信息。仿真结果表明,该算法在有较高响应速度的同时提高了跟踪准确度,且算法实现简单,满足电容器等设备投切控制的要求。 展开更多
关键词 交织变化 窄带滤波 归一化计算 过零点检测
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微波前向散射法研究出血性脑中风 被引量:4
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作者 姜兴 安虹瑾 +2 位作者 彭麟 李小明 王璟珂 《微波学报》 CSCD 北大核心 2019年第4期92-96,共5页
用微波前向散射法探究出血性脑中风的出血量。该法利用脑出血状态及正常大脑状态下收发天线之间传输系数的幅度S21和相位φS21差值变化、以及大脑的电场分布数值的变化来检测脑中风出血位置。文中用三维人体组织电磁仿真软件Sim4Life提... 用微波前向散射法探究出血性脑中风的出血量。该法利用脑出血状态及正常大脑状态下收发天线之间传输系数的幅度S21和相位φS21差值变化、以及大脑的电场分布数值的变化来检测脑中风出血位置。文中用三维人体组织电磁仿真软件Sim4Life提供精细的大脑模型,在大脑中植入直径为10 mm、20 mm、30 mm的血球模型,并将三个血球模型置于大脑同一位置,然后搭建模拟脑出血的实验平台进行实测,由不同规格的试管模拟不同规格的出血量,最终验证了仿真结果与实验结果一致。实验证明,大脑出血量越大对收发天线间传输系数以及电场强度的影响越大。 展开更多
关键词 前向散射法 脑中风 出血量探究 幅相变化 电场分布
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Selective excitation of resonances in gammadion metamaterials for terahertz wave manipulation 被引量:2
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作者 WANG DaCheng HUANG Qin +1 位作者 QIU ChengWei HONG MingHui 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2015年第8期43-48,共6页
A gammadion terahertz(THz) metamaterial embedded with a pair of splits is experimentally investigated. By introducing the pair of splits at different arms, the transmitted amplitude at the resonance frequency can be m... A gammadion terahertz(THz) metamaterial embedded with a pair of splits is experimentally investigated. By introducing the pair of splits at different arms, the transmitted amplitude at the resonance frequency can be manipulated from 61% to 24%. Broadband static resonance tunability from 1.11 to 1.51 THz is also demonstrated via varying the relative split positions at certain arms. The amplitude change and static resonance tunability are attributed to the introduced split pairs, which enable selective excitation of different resonance modes in the gammadion metamaterials. This work promises a new approach to design THz functional devices. 展开更多
关键词 TERAHERTZ gammadion metamaterials TRANSMISSION
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Single-trial ERP evidence for the three-stage scheme of facial expression processing 被引量:4
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作者 ZHANG DanDan LUO WenBo LUO YueJia 《Science China(Life Sciences)》 SCIE CAS 2013年第9期835-847,共13页
Using a rapid serial visual presentation paradigm, we previously showed that the average amplitudes of six event-related potential (ERP) components were affected by different categories of emotional faces. In the curr... Using a rapid serial visual presentation paradigm, we previously showed that the average amplitudes of six event-related potential (ERP) components were affected by different categories of emotional faces. In the current study, we investigated the six discriminating components on a single-trial level to clarify whether the amplitude difference between experimental conditions results from a difference in the real variability of single-trial amplitudes or from latency jitter across trials. It is found that there were consistent amplitude differences in the single-trial P1, N170, VPP, N3, and P3 components, demonstrating that a substantial proportion of the average amplitude differences can be explained by the pure variability in amplitudes on a single-trial basis between experimental conditions. These single-trial results verified the three-stage scheme of facial expression processing beyond multitrial ERP averaging, and showed the three processing stages of "fear popup", "emotional/unemotional discrimination", and "complete separation" based on the single-trial ERP dynamics. 展开更多
关键词 facial expression single trial event-related potential (ERP) three stages
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