Results 11 to 20 of about 36,171 (145)
由于地磁暴在大地产生感应电流以及直流输电系统单极性运行方式与大地形成回路,使得直流电流进入变压器中性点,造成变压器直流偏磁,电流发生畸变,产生谐波。文中在已经研究过的单相特高压变压器直流偏磁计算的基础之上,以230 kV三相五柱式变压器为例,依据单相变压器和三相变压器电路、磁场的区别,利用变压器磁场模型与电路模型建立微分方程,对三相变压器的直流偏磁进行了计算分析。为使计算结果能够快速稳定,在电路中人为串联大电阻,并在计算完成后使用电压补偿的方法将串联电阻所分电压补偿在电路中,根据计算结果可知 ...
王泽忠, 郭苏鑫, 李冰, 张廉杰
doaj
在合成孔径雷达干涉测量中,干涉相干是局部干涉条纹质量的重要评价标准,但是由于各种失相干源的影响,会出现失相干现象,而这可能会丢失重要的形变数据。本文首先利用ENVISAT ASAR的两景影像获得了2009年意大利拉奎拉MW6.3地震的带有失相干现象的同震形变场,对数据预处理后再使用移动窗口克里金法对拉奎拉地震的同震形变场进行插值处理,恢复了形变图的失相干区域,之后进一步通过正反演获得同震形变场,并与上一步的插值结果进行对比分析。结果显示,插值结果与反演结果在极震区吻合得很好 ...
Jintian Li +3 more
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变压器外部噪声控制系统对提升变电站声环境质量具有重要意义。噪声控制系统的布放位置和结构参数选择需要依据变压器空间噪声的干涉衰减和频谱特性。目前对变压器不同位置噪声干涉衰减规律的研究很少。文中测量了山西省内某1 000 kV特高压变压器噪声,研究了变压器A、B、C相以及AB、BC相中间位置噪声干涉衰减规律。变压器A、B、C相声压级随测量点到变压器立面距离增加单调下降,略有波动,分为快衰减段和慢衰减段。变压器AB、BC相中间位置,由于近场干涉作用出现明显的振荡段。在振荡段高频分量单调下降 ...
张超, 刘国强, 芦竹茂, 俞华
doaj
Abstract Background The middle conchal sinus (MCS) (ethmoidal sinus) remains one of the least understood equine paranasal compartments. Despite recognition of its involvement in sinonasal disease, disorders of the MCS often remain underdiagnosed in the absence of computed tomographic (CT) imaging due to limited anatomical understanding and challenges ...
J.‐B. Pavard +3 more
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Through systematic price collection and correction for underreporting and undetected seizures, the global illegal wildlife trade (IWT) is estimated at US$28.4–39.5 billion per year. This finding highlights that previous valuations were underestimates.
Jia Hao Tow, L. Roman Carrasco
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We examined changes in perceived risks associated with chronic wasting disease (CWD) and perceived trust in wildlife agencies over time across 10 studies in eight states. Results indicated that perceived risks to both deer and humans declined the longer the disease had been in a state. Results also indicated that agency trust evaluations were positive,
Jerry J. Vaske, Craig A. Miller
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Climate change drives shifts in suitable habitats for Eurasian lynx and its prey (hare, roe deer) in Mohe, Daxing'anling Mountains. Under RCP scenarios, moderate warming (RCP4.5) promotes substantial habitat expansion, while high‐emission conditions (RCP8.5) lead to strong expansion in the 2050s but slower gains and partial contraction by the 2070s ...
Binglian Liu +5 more
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Using radiotelemetry, we found that the movement and home range of the endangered Sacalia bealei varied significantly across reproductive classes and seasons, with males exhibiting greater movement than females during wet and mating seasons. The species exhibits strong aquatic dependence, favoring deep pools interspaced among riffle‐pool sequences ...
Wing Sing Chan +3 more
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作者利用电阻法和伸长率 温度曲线的测试,研究了R相变和马氏体相变对TiNi记忆合金双向记忆效应(TWSME)的贡献,并研究了热机械训练对相变特征的影响.研究结果表明,热机械训练可导致降温时R相的出现,并且R相变对双向记忆效应的贡献远大于马氏体相变的贡献.在双向记忆效应训练过程中,由于位错的引入,能引起相变点Ms,Mf,Rs,As和Af的下降.
封向东 +4 more
doaj
Human‐caused leopard deaths in Sri Lanka averaged 9.65 ± 4.5 records year−1 over 17 years (2008–2024; n = 164), with records highly clustered in the central highland mosaic ecosystem. Mortality was dominated by adult males and driven primarily by snaring in plantation landscapes, and indicating an increase approximately 0.7–0.8 deaths per year.
Sanjaya Weerakkody +11 more
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