Results 41 to 50 of about 7,148 (168)
Gaoya dianqi, 2023 大型电力变压器绕组的固有振动特性影响其在短路冲击电流下的振动响应及抗短路能力。为了弄清楚固有振动特性与绕组机械参数间的关系，文中建立了计及压板和线圈的绕组轴向振动“质量—弹簧—阻尼”模型，提出了等效质量、刚度和固有振动特性的计算方法。在此基础上，分析了一台SFSZ8-40000/110变压器低压绕组的模态频率和振型，研究了垫块弹性模量、数量和端圈垫块厚度等因素对绕组固有振动特性的影响规律。研究结果表明，绕组各阶轴向振动模态频率之间满足倍数关系，各阶频率对应的振型为绕组不同位置线饼沿轴向的同向和反向振动 ...
刘力卿 +6 more
doaj
The Extraction and Research of Finger Pulse Signal Base on Infrared Absorption [PDF]
, 2015 人体内，循环系统、神经系统等系统的生理信息都以某种方式体现在脉象中。因此通过脉搏检测所获得的脉搏波形图富含人体重要的生理信息，这些信息具有重要的医疗价值，可以用来预测内脏形态及其功能是否出现异常。同时，一般疾病症状出现之前，脉搏生理信息会提前出现。因此，该信号还可以为其他易于引起心血管疾病的病症，如高血压等，提供评估依据和参考。传统医疗检测设备多见于大中型医院，设备体积大，检查费用昂贵，不利于家庭日常保健。立足于现有的脉搏信号检测方法，本文研究并设计了一款基于红外光吸收的指端脉搏信号监测系统 ...
黄金池
core
Analyzing power errors in the optical pumping system of atomic spin comagnetometers [PDF]
The spin exchange relaxation-free (SERF) atomic comagnetometer is a highly sensitive device designed to measure rotation rates with extreme precision.
Jiale QUAN +4 more
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Integrative Conservation, Volume 4, Issue 3, Page 362-380, September 2025.Occurrences of dust storms and long‐distance movement of dust across landscapes is constantly increasing in south Asia. This dust is expected to have profound impact on vegetation health and sustainability as dust may contribute to nutrient budgets of the forest ecosystems, while it could impart various stresses to the plants.
Shree P. Pandey +2 more
wiley +1 more source
Gaoya dianqi, 2012 目前采用频率响应法诊断变压器绕组变形的应用相当广泛,但是在实际测量中,其测试结果会受到诸多因素的影响而失真,若不能准确识别这些影响因素,测试结果的可比性将大大降低,从而给测试结果的分析、判断带来困难甚至错误。笔者结合频率响应法检测技术在天水电网的应用情况,总结了现场由于各种影响因素造成的绕组频率响应曲线异常的实例并将其逐一归类,为今后判断变压器绕组变形提供依据。
曹小龙 +6 more
doaj
Grid-connected control strategy of GFM inverter in solar-powered ship photovoltaic system [PDF]
Objective The paper aims to solve the problem of the overall stability of the ship's power system being reduced due to the use of grid-following (GFL) control for grid connection in existing solar ship photovoltaic (PV) power generation systems ...
Chunhua ZHAO +2 more
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Risk, Hazards &Crisis in Public Policy, Volume 16, Issue 1, March 2025.Abstract Coastal storms are likely to increase in frequency and become even more damaging. An unresolved policy issue is whether current residents should receive federal subsidies through such programs as the Federal Flood Insurance Program or the FEMA disaster relief program that encourage thembe encouraged to rebuild in the same locations that have ...
Risa Palm +2 more
wiley +1 more source
Gaoya 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
Research on Control Loop Fault Diagnosis [PDF]
, 2014 控制回路故障诊断旨在提高工业生产装置操作的安全性与可靠性，一直受到学术界与工业界的广泛关注。工业过程控制回路涉及多种复杂问题，其故障可能存在多种形式。论文研究控制回路中模型预测控制（MPC）的模型失配故障、回路振荡故障，以及基于数据驱动的贝叶斯故障诊断。针对工业现场的实际问题，提出了外加测试信号的模型误差诊断，基于频域分析的回路振荡监测，和基于期望极大化（EM）算法的贝叶斯故障诊断方法。本文具体研究内容如下： 针对MPC模型失配问题，提出了基于外加低幅正弦测试信号的模型诊断方法 ...
张抗抗
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Integrative Conservation, Volume 3, Issue 4, Page 294-311, December 2024.Freshwater biodiversity in China is threatened by multiple anthropogenic factors, and while there are some reasons to suppose it may be possible to bend the curve of biodiversity loss, the variety of threats and their likely interactions with ongoing climate change provide little basis for optimism. For example, the historic overexploitation of Yangtze
David Dudgeon
wiley +1 more source