Results 21 to 30 of about 5,941 (136)

基于光纤测振系统的变压器绕组与铁心耦合振动特性研究

open access: yesGaoya dianqi, 2019
变压器绕组和铁心的振动决定了油箱振动和变压器整体的声辐射水平。以往研究忽略了因结构连接而引起的铁心和绕组之间的耦合振动,简单地认为铁心和绕组的振动相互独立、互不影响,因而所得结论并不能真实反映变压器内部的实际振动情况。为了全面了解油浸式变压器铁心和绕组的耦合振动特性,文中建立了基于光纤振动加速度传感器的试验平台,对一台三相50 kVA变压器进行了试验研究,获得了内部结构(绕组和夹件)在空载、负载和变负载条件下的振动特性。研究结果表明,变压器空载时,铁心振动向绕组传递引起绕组多频振动 ...
高树国   +6 more
doaj  

Incremental Analysis Updates in a Convective‐Scale Ensemble Kalman Filter Using Minute‐by‐Minute Phased Array Radar Observations

open access: yesJournal of Advances in Modeling Earth Systems, Volume 17, Issue 9, September 2025.
Abstract Rapid‐update data assimilation (DA) cycles, particularly during the early stages of the assimilation process, often suffer from physical imbalances that degrade the quality of analyses and lead to a rapid decline in forecast skill. This study evaluates the impact of combining the incremental analysis update (IAU) method with the ensemble ...
Zhaoyang Huo   +6 more
wiley   +1 more source

动力吸振器在反射镜角度振动抑制上的应用

open access: yesHe jishu
上海硬X射线自由电子激光装置X光束传输距离超过1 km,反射镜的角度振动对实验站样品处的光斑影响很大。本文旨在探讨动力吸振器在减小反射镜角度振动的可行性。针对反射镜角度14.6 Hz的环境振动,设计了一个可变刚度的动力吸振器,将其应用于上海硬X射线自由电子激光装置的反射镜调节系统中,以期实现该频率的振动抑制。实验结果表明,通过将动力吸振器的频率调至14.6 Hz,反射镜调节系统14.6 Hz的振动从154 nrad降低至27.9 nrad,其他频率的振动基本无明显变化,整体反射镜角度的振动从193.2 ...
袁 浩然   +6 more
doaj   +1 more source

Tree mycorrhizal associations regulate relationships between plant and microbial communities and soil organic carbon stocks at local scales in a temperate forest

open access: yesFunctional Ecology, Volume 39, Issue 6, Page 1550-1566, June 2025.
Read the free Plain Language Summary for this article on the Journal blog. Abstract Forests store substantial amounts of soil organic carbon (SOC), but SOC stocks differ strongly between forest ecosystems dominated by arbuscular mycorrhizal (AM) or ectomycorrhizal (EcM) fungi.
Mengxu Zhang   +10 more
wiley   +1 more source

不同电压等级电力变压器振动特性统计分析

open access: yesGaoya dianqi, 2019
振动信号分析法是带电检测变压器绕组及铁心机械状况的有效手段,但目前现场运行变压器振动特性掌握还不够充分,对不同电压等级变压器振动信号进行统计分析具有重要意义。基于变压器铁心及绕组振动机理的分析,利用所建立的振动测量系统,文中对77台在运电力变压器进行了振动信号测量与统计,电压等级涵盖了110~750 kV,分析了振动信号基频振幅、主频、基频比重以及频谱复杂度等振动参量的变化规律,基于大量现场振动普测数据,得到了不同电压等级变压器振动参量的特征值范围及其概率分布。文中给出了不同电压等级变压器的振动特性 ...
黎大健   +3 more
doaj  

Æ E Æ Å – Reshaping the Role of Træna Fishermen

open access: yes, 2022
This diploma project aims to strengthen the viability of Træna’s community by proposing an ocean research facility in the archipelago, enabling the next generation of local fishermen to collect oceanographic data while working at sea. The idea of the fisherman as oceanographer is inextricably linked to the architectural program on the island of ...
openaire   +1 more source

China's Eco‐Civilisation, Climate Leviathan, and Hobbesian Energy Transition

open access: yesAntipode, Volume 57, Issue 3, Page 830-861, May 2025.
Abstract Scholars have hitherto tended to theorise China's ecological civilisation project either as a form of environmental authoritarianism or as a vision of eco‐socialism. This paper contributes to the conversation by conducting a textual analysis of Chinese scholarly discussions on eco‐civilisation.
David Chen
wiley   +1 more source

地铁车辆段车致振动测试及楼板振动放大研究

open access: yesZhendong Ceshi yu Zhenduan
为研究地铁车致车辆段振动特性,评估振动对车辆段的影响。首先,依托重庆某大型车辆段上盖物业项目,重点采集钢轨、轨枕(咽喉区)、检修坑立柱(停车区)、建筑承重柱以及上盖楼板等处的振动加速度,借助经验公式对上盖建筑的二次结构噪声进行预测;其次,基于板壳振动理论建立承重柱‑楼板系统振动模型,研究上盖楼板振动放大特性,揭示振动放大机理。研究表明:咽喉区整体振动水平大于停车区;振动从钢轨传播到承重柱的过程中,1.25~200 Hz的振动明显衰减;上盖楼板由于振动叠加效应出现振动放大现象;二次噪声主要集中在50 ...
doaj   +1 more source

带气动操动机构GIS断路器振动特性测试及改进

open access: yesGaoya dianqi, 2016
针对某一带气动操动机构GIS断路器分、合闸操作异常振动问题展开研究。首先在运行现场测量了断路器动作过程中的振动加速度,发现气动机构在分闸操作时的振动是导致异常振动发生的重要原因,同时研究发现降低气动机构工作气压仍不足以避免异常振动问题;然后分别对带气动和液压操动机构的试验断路器的振动强度进行了仿真计算和现场测试,发现带竖直方向布置液压机构的断路器的振动强度最小且持续时间最短。表明采用竖直方向布置液压操动机构后,GIS断路器的振动特性明显改进。
杨鼎革   +5 more
doaj  

Domain‐adaptation‐based named entity recognition with information enrichment for equipment fault knowledge graph

open access: yesIET Collaborative Intelligent Manufacturing, Volume 6, Issue 4, December 2024.
Domain‐adaptation‐based named entity recognition with information enrichment is proposed for developing an equipment fault knowledge graph. A question answering application of the equipment fault knowledge graph is proposed. Abstract Numerous files, such as records and logs, are generated in the process of equipment diagnosis and maintenance (D&M ...
Dengrui Xiong   +3 more
wiley   +1 more source

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