Results 41 to 50 of about 7,537 (169)
Gaoya dianqi, 2010 系统地以参函数的角度介绍了6种典型的Cohen类时频分布。从理论和应用效果上分析了各分布的交叉干扰项衰减和时频分辨率性能。针对局部放电信号的非平稳性,展现了各分布在处理仿真和实际脉冲信号的应用效果。试验结果表明,平滑伪Choi-Williams分布（SPCWD）对局放脉冲非平稳信号引发的短时变化具有高度的敏感性,更为适合表征局放脉冲信号的时变信息。据此,可提取单个脉冲波形的时频特征参数、分析多个连续放电脉冲的时频变化,从而用于放电类型的模式识别以及深入研究绝缘系统中的局部放电机理。
何平 +5 more
doaj
Research on Propagation Law of Radar Signal in Tunnel Segment and Analysis of Radar Signal from the Void [PDF]
, 2017 目前我国隧道建设发展迅速，探地雷达以其高分辨率、快速、无损等优点在隧道工程质量隐患检测方面已被广泛应用。本文针对隧道检测中两个热点问题地铁盾构隧道注浆层分布检测、隧道衬砌背后空洞的识别进行了相关研究工作，取得了一些研究成果： 1、采用时域反射计对某地铁站附近典型土样及壁后注浆浆液的电性参数进行测试，结果表明：泥岩土样电性参数测量结较为稳定，泥岩土样的含水量在27%~42%间，相对介电参数介于14.3-27.7。介电常数随着土层含水率增大而增大。浆液随龄期的变化介电常数变化较大 ...
田博
core
Application of Split-frequency AVO Technology in the Evaluation of Middle-depth Thin Reservoirs in the Xihu Depression [PDF]
Owing to the combination of factors such as the thin layer structure, thickness, and fluid, the wave field characteristics of the thin layer are relatively complex, which results in large uncertainties in the thin layer AVO analysis.
Bingying LI +4 more
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Journal of Linguistic Anthropology, Volume 35, Issue 2, August 2025.Abstract This article argues that social actors' media ideologies about digital interfaces are key to the enregisterment of online activities. Focusing on an online register emergent from user activities around Year, Hare, Affair (YHA)—a state‐aligned Chinese animation—I explore how different metadiscourses evaluate this register by entextualizing ...
Jiarui Sun
wiley +1 more source
Gaoya dianqi, 2015 笔者以800 kV GIS（gas insulated switchgear）高压开关设备的抗震性能为研究对象,采用模态分析理论对设备进行动力特性分析,得到了结构自振频率和振型。分别利用反应谱理论和时程分析理论对结构进行地震动特性分析。通过反应谱分析和输入天津波、EI-Centro波、taft波的动力时程分析,讨论了这两种分析方法结果上的一致性与局限性。并根据几种不同地震波对高压开关设备的不同影响,得出相对于taft波振幅和持时较小的天津波对设备产生破坏作用最大;经过对频率调整,具有相同幅值的两种EI ...
林莘, 李丹, 徐建源
doaj
Gaoya dianqi, 2021 由断路器和合成试验标准规定的工频恢复电压(PFRV)推导出合成试验时PFRV的衰减时间常数,分析了PFRV的严酷度,给出了工频恢复电压电抗器的正确定值方法,以及它的衰减时间常数的解析计算式。
庄稼人, 张玲, 郑占锋
doaj
Multiband FMCW Radar LSS-target Detection Dataset (LSS-FMCWR-1.0) and High-resolution Micromotion Feature Extraction Method [PDF]
Detection of small, slow-moving targets, such as drones using Unmanned Aerial Vehicles (UAVs) poses considerable challenges to radar target detection and recognition technology.
Gang Yu +6 more
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Ultrasound in Obstetrics &Gynecology, Volume 65, Issue 4, Page 456-461, April 2025.Abstract Objective To investigate the ongoing parvovirus B19 (B19V) outbreak among pregnant women in Germany and its connection to the coronavirus disease 2019 (COVID‐19) pandemic. Methods This retrospective cohort study analyzed anonymous data regarding serologically confirmed B19V infections during pregnancy between January 2014 and April 2024 across
J. Jiménez Cruz +14 more
wiley +1 more source
Gaoya dianqi, 2005 提出了一种基于高斯线调频小波变换诊断电机故障的新方法。线调频小波变换是信号的时间-频率-尺度变换, 具有比小波变换及其它时频分析更强的非平稳信号分析功能。利用高斯线调频小波变换作电机故障信号的能量谱估计,可提取电机故障信号的频率成份。试验结果表明,这种方法比Fourier变换和小波变换频率分布的能量更集中。
胡国胜, 朱锋峰, 任震, 涂用军
doaj
Role of low‐impact‐factor journals in conservation implementation
Conservation Biology, Volume 39, Issue 2, April 2025.Abstract Academic review, promotion, and tenure processes place a premium on frequent publication in high‐impact factor (IF) journals. However, conservation often relies on species‐specific information that is unlikely to have the broad appeal needed for high‐IF journals.
Jonathan J. Choi +8 more
wiley +1 more source