Results 41 to 50 of about 23,201 (124)
为了能在放电故障发展的初始阶段发现并监测其发展过程,及时分析判断其故障状态和严重程度,从而提高运行的可靠性,笔者针对几种常用局部放电监测方法的不足,通过油中溶解气体分析及相关电气试验,准确判断了某大变压器的内部放电性质、严重程度及可能发生的大致部位。利用脉冲电流法和超声波检测法的综合运用,成功地检测了该变压器的内部放电故障、发展趋势,并精确地进行了故障定位,在进人检查时上述方法判断和分析的结论得到了验证。
徐澄, 肖荣
doaj
利用机器学习中的主成分分析法(PCA)提取了2022年泸定MS6.8地震的M5.0余震(2022年10月22日)的特征主成分时程,对泸定MS6.8主震的地震动时程进行模拟。在此过程中,将主震目标台站的地震动峰值加速度和反应谱作为约束条件,利用粒子群优化(PSO)算法计算特征主成分时程的组合系数。结果显示模拟结果与真实记录较为一致。这表明:利用机器学习算法能够通过提取余震的特征主成分时程对目标地震进行模拟;在进行小区域地震动模拟时 ...
Kai Chen, Hua Pan
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ABSTRACT The growing concern over human health issues, driven by increasingly severe electromagnetic pollution from 5G communication, has made the urgent development of high‐performance electromagnetic wave (EMW) absorbing materials. Although carbide‐based materials are promising because of their conductive and polarization losses, existing single ...
Chenqiang Duan +9 more
wiley +1 more source
Read the free Plain Language Summary for this article on the Journal blog. Abstract The nested subset pattern (nestedness) has been widely used to explain species distributions in island and fragmented systems. Mountain sky islands serve as critical natural laboratories for understanding the evolutionary consequences of geographic isolation and climate
Caiwen Zhang +5 more
wiley +1 more source
南郭寺南山佛法身舍利塔是一幢新建于高设防烈度地区山坡平地上的仿古塔建筑,设计使用年限100年,建筑造型和结构体系稍复杂于常规建筑。首先通过动力特性分析得到其自振周期和振动模态,而后采用振型分解反应谱法和时程分析法,使用有限元软件Midas Gen对结构在小震、中震和大震作用下的地震响应进行了数值分析。因在结构总说明中,只用到了设计使用年限50年的地震作用,而未将其调整为100年,所以分析中均取用两组地震动参数,即设计使用年限50年和100年。小震和中震的地震响应计算均采用弹性法,分析结果满足抗震性能要求。
李灵君 +4 more
doaj +2 more sources
为解决某GIS母线中波纹管的最大压缩位移和疲劳寿命究竟能否同时满足工程指标的难题,应用工程计算和有限元分析分别加以计算,然后通过两种计算结果和实验验证进行比较,以期获得哪种方法更精确可靠。为达此目的,文中给出了工程计算和有限元建模的详细过程。按工程计算方法得到的最大压缩位移结果无法满足工程指标,而有限元分析计算方法,却可以达到工程指标,且有较大的安全裕度。有限元分析还揭示了满足大压缩位移的机理,计算结果符合某GIS工程同时需要的压缩位移和疲劳寿命。经型式试验也验证了模拟的正确性 ...
王玉, 杨知我
doaj
Accelerating Just Energy Transitions in Brazil: Pathways for Social Development
ABSTRACT This critical article analyzes energy poverty in Brazil from the theoretical perspective of distributive justice, proposing the implementation of a new social regulation called Contribution to Social Development. The goal is to support the process of a just energy transition leading to a broader debate on energy planning and social issues ...
Marcio Giannini Pereira +5 more
wiley +1 more source
【目的】了解基因 Aurora- A 在喉癌中的表达情况及了解其作为预测喉癌预后的新指标的可能性。【方法】用免疫组化的方法检测我科 1995- 1999 年 77 例喉癌标本中 Aurora- A 的表达, 随访 3~136 月, 中位随访时间为 71.93 月, 用统计软件 SPSS11.0 分析 Aurora- A 的表达与喉癌患者年龄、性别、临床分期、临床分型、肿瘤分化程度等的关系及其与预后的关系。【结果】Aurora- A 在喉癌标本中的表达率为 71.4% (55/77 ...
陈福进 +3 more
doaj
NEPA “Modernization”: From the Trump Administration to the Biden Administration
ABSTRACT Researchers have recently examined changes to American environmental policy under the Trump administration's first term, and to a lesser extent, under the Biden administration. Scholars have largely not considered changes to the National Environmental Policy Act (NEPA), one of the earliest environmental laws in the United States, and a law ...
Michelle L. Edwards
wiley +1 more source
Governance of Climate‐Induced Relocation in the US: An Exploration of Institutional Complexity
ABSTRACT Climate change has and will continue to have a profound effect on both individuals and the communities in which they reside. A pressing question is how communities forced to confront climate‐induced catastrophe—including both rapid and slow‐onset hazards—undertake the decision of how and when to relocate, particularly given the multiple scales
Christopher S. Galik, Brad A. Johnson
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