Results 41 to 50 of about 999,978 (161)
Gaoya dianqi, 2009 受变压器内部复杂结构的影响,局部放电超高频信号在变压器内部的传播特性非常复杂。笔者通过变压器局部放电超高频实验研究,分析了油纸屏障对变压器局部放电被测超高频信号的影响。设计了油中气隙放电、油中沿面放电和油中电晕放电3种局部放电模型,在实验油箱中进行局部放电实验,采用超高频小环天线进行放电信号检测,在有无油纸屏障情况下获得了局部放电超高频信号实测数据,对所测局部放电超高频信号在时域和频域上进行了对比分析。结果表明,油纸屏障对超高频信号幅值衰减及信号功率谱有一定影响。
高红武 +4 more
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Predictive evolutionary genomics: principles, validation, and practice
New Phytologist, Volume 252, Issue 1, Page 36-48, October 2026.Summary Climate change and habitat loss are driving rapid evolutionary responses in populations world‐wide, which creates an urgent need for evolutionary forecasting in conservation and agriculture. Such forecasting can be categorized into three time scales: trait‐based models that use multivariate quantitative genetic equations to project correlated ...
Daniel Ortiz‐Barrientos +5 more
wiley +1 more source
Gaoya dianqi, 2018 基于高频法检测局部放电技术已经相对成熟,为了现场检测和对变压器运行状况做出准确诊断,文中提出了利用高频法检测分析放电信号传播特性的方法。通过建立仿真模型确定了频带选择范围,并建立试验平台,利用多传感器同时测量和采集实时信号,对比研究了局部放电在变压器内部传播后以及在不同位置放电时高频信号的频谱特性。结果表明,高频局部放电检测法能够对变压器缺陷进行高效检测且高频信号变化规律明显,为实际的波形检测提供了试验依据。
王新, 苏欢欢, 高树国, 张鹏
doaj
Neutral interactions among non‐native plants are common
New Phytologist, Volume 252, Issue 1, Page 292-309, October 2026.Global distribution of studies and overall effect of co‐invasion for all metrics of non‐native plant performance combined. Summary Globalization has accelerated the establishment of non‐native plant species, increasing the prevalence of multispecies co‐invasions; yet interactions among co‐invaders remain poorly understood.
Feng He +7 more
wiley +1 more source
Dianci bileiqi, 2021 为准确获取不同温度条件下胶浸纸套管绝缘性能变化规律,在高低温试验箱中开展了±100 kV穿墙套管在不同温度下的频域介电谱测试,获得了被测试套管的绝缘电阻、工频介损、工频电容量等绝缘特征参数。研究结果表明:胶浸纸套管各绝缘性能参量对温度变化的反应较为敏感,工频介损因数随温度的上升呈现先减小后逐渐增加的趋势;绝缘电阻随温度的升高逐渐减小,且减小幅度较大;在低频区域,胶浸纸套管的介损随温度的升高逐渐增大,高频区域相反,介损频域谱随温度的升高整体向高频方向移动;胶浸纸套管的复电容实部在高频段基本保持不变,C ...
张寒 +5 more
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Integrative Conservation, Volume 5, Issue 3, Page 306-316, September 2026.ABSTRACT In today's rapidly urbanizing world, the survival of wildlife in cities faces significant challenges, and the attitudes of urban residents toward wildlife play a crucial role in their survival. Otters, as top predators in freshwater ecosystems who are highly sensitive to environmental changes, had once gone extinct in Shenzhen—a megacity ...
Changning Liu +5 more
wiley +1 more source
, 2011 利用传统方法实现高重频高压窄脉冲源受制于的器件性能,因而 提出了频率叠加的新思路。基于超快电子学和频率叠加理论,利用MARX电路产生多路高压窄脉冲,通过同步系统控制多路触发信号延时,使多路脉冲耦合成一路 输出,实现高重频高压窄脉冲输出。实验中两个单路高压窄脉冲的幅度为2.56 kV,宽度为7.13 ns,重复频率为32 kHz,两路脉冲耦合后,输出脉冲幅度为2.46 kV,宽度为7.49 ns,重复频率为64 kHz。该实验验证了设计思路的可行性,实现了输出脉冲重复频率倍增 ...
阮驰 +5 more
core
, 1983 用光振子调制连续输出的He-Ne激光,配合转鼓相机,形成了频闪He-Ne激光高速干涉摄影装置。摄影频率达每秒20000幅。配合超高速转镜相机 ...
夏生杰
core +1 more source
滴灌频率和施氮量对温室西葫芦土壤水分、硝态氮分布及产量的影响
Shuitu Baochi Xuebao, 2018 2016年和2017年在北方寒旱地区日光温室西葫芦栽培中，灌溉定额为269.87 mm，设置2个滴灌频率（低频W1：7天1次，高频W2：2天1次）和2个氮素水平（适氮N1：375 kg/hm2，高氮N2：565 kg/hm2），研究不同处理对温室西葫芦土壤水分、硝态氮分布及西葫芦产量的影响。结果表明：（1）高频（W2）滴灌提高了0—40 cm土层的土壤水分，减少了水分的深层下渗。（2）高氮（N2）施肥各土层硝态氮含量较高，适氮处理配合高频次滴灌根区0—40 cm硝态氮含量维持在相对适宜水平，40—80 ...
郭鹏飞 +4 more
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Functional Ecology, Volume 40, Issue 9, Page 2843-2860, September 2026.Read the free Plain Language Summary for this article on the Journal blog. Abstract Drylands are mainly structured by both vascular plants and biological soil crusts (biocrusts), the latter often regarded as a self‐organizing component of these ecosystems.
Haoran Luo +13 more
wiley +1 more source