Results 41 to 50 of about 469,077 (150)

接线方式对配电变压器绕组频率响应影响

open access: yesGaoya dianqi, 2017
通过对1台容量为200 kVA的S11-M-200/10型三相变压器的试验,分析比较了不同接线方式对频率响应曲线测量的影响。特别是对变压器外壳是否接地、注入电压的方向、非测试绕组的状态等的影响进行了深入的研究。研究表明:接线方式的不同可能导致频率响应曲线的巨大差异,某些情况下这些差异比绕组变形、变压器故障导致的差异更大。因此,笔者建议在进行变压器绕组频率响应曲线测量时应该保持各实验条件的一致。
王珊珊   +3 more
doaj  

Bifunctional Competitive Structure of Biomass Carbon‐Derived Metacomposites for Tunable ε′‐Near‐Zero and ε′‐Negative Responses

open access: yesRare Metals, Volume 45, Issue 2, February 2026.
ABSTRACT Regulating negative parameters of metacomposites is mainly limited by their unclear mechanisms, which affects their practical applications in new sensing, communication, electromagnetic (EM) protection and other fields. This work proposes a dual‐functional competitive design strategy based on the waste corncob‐derived carbon/polyaniline ...
Qiuyun Yang   +4 more
wiley   +1 more source

Finding floral and faunal species richness optima among active fire regimes

open access: yesConservation 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

综合考虑偏压和温度因素实现光探测器本征频率响应的提取

open access: yes, 2010
频率响应是探测器的重要特性之一,本征频率响应决定了探测器的响应带宽.在前人使用扣除法提取探测器本征频率响应工作的基础上,综合考虑反向偏置电压和温度等两种影响频率响应的因素,分别进行基于反向偏置电压和温度的实验.结合物理模型对实验及拟合结果进行分析讨论 ...
王礼贤   +7 more
core  

诸葛菜下胚轴高频率植株再生因素研究

open access: yes四川大学学报. 自然科学版, 2000
诸葛菜外植体再生力较强 ,可以作植物体细胞遗传学的实验材料 .以生长于两种不同MS培养基 (含或不含激素 )上的诸葛菜无菌苗下胚轴为外植体 ,研究不同外植体 ,不同激素组合和硝酸银对下胚轴高频率再生的影响效应 .结果如下 :激素的影响效应最显著 ,最适激素组合为MB1N ,植株再生频率高达 92 .51% .硝酸银对再生频率较高 ,激素组合 (6 BA +NAA)作用效应不明显 ,激素组合 (6 BA +2 ,4 D)只提高下胚轴再生频率 .不同外植体作用效应的差异只表现于培养基MB1N和MB2N中 ...
徐怀亮, 罗鹏, 陈艳红
doaj  

地震载荷下圆柱型储罐内晃荡响应的数值模拟

open access: yesDizhen xuebao
为了研究地震载荷下圆柱型储罐内液体的晃荡特性,选用15种典型的地震信号,采用计算流体力学软件Fluent进行数值仿真,以探究地震的频率、频率成分、峰值速度以及峰值加速度对晃荡波高和水动压的作用规律。结果表明:① 地震主频是影响自由液面响应的主要因素之一,当其接近储液的一阶固有频率时,会激发强烈的非线性晃荡现象,工程中应添加减晃装置;② 波高与地震峰值速度呈较强的正相关,并且低频成分的地震信号激发的波浪较其它频率成分的地震信号更为剧烈;③ 水动压在储罐上部呈对流模式分布,主要受地震主频和频率成分的影响 ...
Xin Jin   +7 more
doaj   +1 more source

Threshold responses of floating meadow fish communities to floodplain forest cover in the lower Amazon River

open access: yesConservation Biology, Volume 39, Issue 6, December 2025.
Abstract Forest cover is positively associated with fish biomass and fisheries yield in the Amazon River floodplain, and many species enter flooded forests to feed, spawn, or seek refuge from predation. Floating macrophyte beds, known as floating meadows, in Amazon floodplains support high fish diversity and serve as nursery habitat for many fishes of ...
Sam Grinstead   +6 more
wiley   +1 more source

直接扣除法测量半导体光放大器频率响应

open access: yes, 2007
在光电子器件散射参量定义的基础上建立了基于直接扣除法的半导体光放大器频率响应测量系统,测量中通过扣除激光器和探测器系统的频率响应,得到放大器固有的频率响应。对InGaAsP体材料行波腔半导体光放大器样品进行了测螬,得到了放大器在不同注入光功率和不同偏置电流下的频率响应曲线。这些曲线很好地反应了半导体光放大器的增益饱和和噪声特性,进一步分析发现半导体光放大器对低频调制信号的放大能力弱于对高频信号的放大能力,分析认为其原因在于半导体光放大器的载流子寿命有限导致低频信号长时间消耗载流子时 ...
黄永箴   +5 more
core  

基于欧氏距离分析的电力变压器绕组变形程度与类型的诊断方法

open access: yesGaoya dianqi, 2020
频率响应分析法是检测电力变压器绕组变形的常用诊断方法之一。近年来,频率响应分析法的检测流程趋向标准化,但寻求合适的算法对频响曲线数据进行量化分析仍需深入研究。文中将频响曲线数据的量化分析看作一个概率分类问题,提出了应用欧氏距离分析诊断变压器绕组变形程度和类型的新方法。研究结果表明,欧氏距离分析能够有效地对变压器绕组变形程度进行诊断,且与先前研究提出的数学指数方法相比,该方法对变形程度的诊断结果具有更高的线性度。同时,在检测频段分段后获取子频段的欧氏距离分布的基础上 ...
张重远   +6 more
doaj  

Investigation of microbial contamination of commercial Romanowsky stain variant solutions used in veterinary clinics

open access: yesVeterinary Dermatology, Volume 36, Issue 5, Page 613-620, October 2025.
Abstract Background Diff‐Quik (DQ) staining is widely used in clinical practice for its ease of use and rapid results. However, its potential contamination remains a concern. Hypothesis/Objectives This study aimed to investigate DQ solution contamination in veterinary hospitals and identify factors affecting it through a questionnaire on stain usage ...
Minji Cho, Seulgi Bae
wiley   +1 more source

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