Results 31 to 40 of about 1,009,107 (167)
Gaoya dianqi, 2019 文中提出了一种气体绝缘组合电器（gas insulated switchgear,GIS）超声波检测异常信号的时频特征计算与诊断方法。首先运用希尔伯特—黄变换（Hilbert-Huang transform,HHT）得到描述超声波信号包络线的时频特征的Hilbert幅值谱。在此基础上,给出了离散条件下Hilbert边际谱与平稳性指数的计算方法,分别表示信号中各频率成分的总强度和平稳性。然后将Hilbert边际谱与平稳性指数结合起来分析,可以直观读取信号的时频特征,进而推断出异常气室的故障原因 ...
管敏渊 +7 more
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Genomic responses to increased temperature and pollinator selection in Brassica rapa L.
New Phytologist, Volume 250, Issue 2, Page 1231-1247, April 2026.Summary Rapid environmental change reshapes both abiotic stress and biotic interactions, yet it remains unclear how these combined forces structure plants' genomic adaptation. In particular, the joint influence of temperature and pollinator identity, two ecological axes undergoing simultaneous global shifts, has rarely been quantified at genomic ...
Yanqian Ding, Florian P. Schiestl
wiley +1 more source
Auto-focus technology and its application based on image processing
, 2009 Auto-focusing technique is an important method to improve the precision,intelligentization,automatization for the indentation diameter measurement.The paper introduces an auto-focus method of indentation diameter measurement based on image processing ...
Chen, Xiaomei, Yang, Tao, Zuo, Yong
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Gaoya dianqi, 2001 应用小波均方谱对仿真局放信号进行了分析 ,得到了一个二维的时间—尺度等能量分布图。计算仿真结果与FFT频谱图相比较 ,表明小波均方谱具有良好的时频特性 ,即有多分辨率分析的能力 ...
赵中原, 邱毓昌, 王建生
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European Policy Analysis, Volume 12, Issue 2, Spring 2026.ABSTRACT This article explains why the European Union Wildfire Risk Management instruments have evolved since the 1980s, even though the underlying patterns of wildfire events have remained largely unchanged. It argues that these changes stem from competing institutional actors promoting distinct policy frames within the European Union's (EU ...
Damien Ballereau, Sabine Saurugger
wiley +1 more source
, 2017 随着社会经济和科学技术的高速发展，对时间频率传递和同步的需求越来越高，特别是在基础科学、深空探测、现代高科技装备和系统中，时间的精确性及稳定性至关重要。基于光纤的时间频率传递成为未来高精度地面时间同步网络的主要发展趋势。该研究以INSPEC数据库为数据源，采用专业数据分析工具Thomson Data Analyzer（TDA）对光纤时间频率传递研究论文进行数据挖掘和定量分析，探讨该领域的研究现状、主要研究力量、研究热点及发展趋势，以期为时间频率科研工作者、决策者以及我国时间频率系统的发展 ...
瞿海燕, 黄鸾鸾, 潘慧玲
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Gaoya dianqi, 2019 为更有效在现场开展GIS局部放电检测,及时准确发现设备内部缺陷,特别是盆式绝缘子局部放电缺陷,文中研究了基于特高频时频定位分析的GIS局部放电综合定位方法。将多通道时延定位法和多通道小波时频分析法联合应用,通过局部放电特高频信号的时域和频谱变化特征,结合设备内部结构、装配工艺等情况,实现GIS局部放电综合精确定位。该方法在某500kV变电站220kV GIS带电检测中进行了应用,精确定位一处盆式绝缘子表面放电缺陷 ...
廖新征 +5 more
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
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Finding floral and faunal species richness optima among active fire regimes
Conservation Biology, Volume 39, Issue 6, December 2025.Abstract Changing fire regimes have important implications for biodiversity and challenge traditional conservation approaches that rely on historical conditions as proxies for ecological integrity. This historical‐centric approach becomes increasingly tenuous under climate change, necessitating direct tests of environmental impacts on biodiversity.
Zachary L. Steel +8 more
wiley +1 more source
, 1991 本文从能量平衡的原理出发，分析了垂直管中脉动多相流动体系的各宏观能量及其表达形式，并作了能量总衡算，导出了压降同相含率的关系式：-Δp = ε_s(ρ_s - ρ_1)Hsg + ρ_1Hsg - ε_g(ρ_1 - ρ_g)Hsg - 0.5ρ _f(rω_m)_2 + 0.5ξε_1ρ_1(U_1/ε_1)~2 (3.4) 基于脉动增大气泡表面能、导致气泡失稳而破裂的设想，导出了脉动分裂气泡直径的关系式：d_(Bn) = 2~(-n/3)d_(BO) (3.15) 式中，n = 3Ln(1 ...
罗建军
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