Results 41 to 50 of about 1,082,401 (195)
Gaoya dianqi, 2017 接地电阻是衡量接地体性能的重要指标。为降低方框带射线型接地体冲击接地电阻,文中采用模拟试验方法,在双层土壤环境下,研究水平分支对不同接地体冲击特性与散流分布的影响。结果表明:对于单根水平接地体,分支呈120°三段式结构的改型接地体的降阻效果最优;相较于简单方框带射线型接地体,添加水平分支,且分支呈120°的三段式结构可减小电感效应,使其分支端部的流散电流增大,火花放电更为强烈,使得平均降阻百分比可达10%。增加水平分支有利于降低接地体冲击接地电阻,需根据具体接地体尺寸改进。
肖磊石 +5 more
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Journal of Animal Ecology, Volume 95, Issue 7, Page 1178-1193, July 2026.This population‐comparative study reveals that male and female parents respond differently to social and ecological conditions. This sex‐specific responsive strategy is related to the incongruent parental care systems across populations in Chinese penduline tits.
Jia Zheng +5 more
wiley +1 more source
Dianci bileiqi, 2014 为了研究垂直接地体发生故障后对暂态接地阻抗的影响,笔者以接地体表面有细缝和局部腐蚀两种状态模拟故障接地体。运用时域有限差分（FDTD）法,通过Matlab编程实现对垂直接地体发生不同故障类型和故障点到接地体入地端的距离与暂态接地阻抗的变化规律的分析。分析结果表明:垂直接地体表面有细缝和局部腐蚀时暂态阻抗大于正常时的值;故障点和垂直接地体入地端之间的距离与暂态阻抗值的变化量成反比关系;在雷电流快速泄流的过程中故障接地体暂态阻抗的变化最显著。研究结论为防雷接地设计,接地体腐蚀状态检测提供了理论依据和实践参考。
邓慧都 +5 more
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Dianci bileiqi, 2022 准确确定杆塔接地体冲击接地电阻对于提高输电线路耐雷水平具有重要的意义。基于有损长线原理的电路理论法，在仿真软件ATP-EMTP中建立接地体冲击散流模型，研究考虑火花效应时接地体冲击接地电阻的有效确定方法。以一接地体在波形为2.6/50μs、幅值为20 kA的雷电流作用下为例进行冲击特性仿真分析，结果表明，采用迭代修正法修正火花放电区域接地体半径，得到的冲击接地电阻更准确。本研究所得结论可为杆塔接地工程改造及优化设计提供有效参考依据。
杨秋玉, 郑小刚
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The underappreciated roles of fog and dew on vegetation and biocrusts
New Phytologist, Volume 251, Issue 1, Page 46-63, July 2026.Summary Fog and dew represent minor components of ecosystem water budgets in most ecosystems. However, fog and dew can play an essential role in ecosystem dynamics and are particularly important for water‐limited systems. In addition to serving as direct water inputs, fog and dew can influence microclimate and water redistribution, thereby promoting ...
Lixin Wang, Yue Li, Mengyun Sun, Na Qiao
wiley +1 more source
Dianci bileiqi, 2017 利用CDEGS仿真计算了典型杆塔接地网的接地电阻,首先对比了柔性石墨接地体与圆钢、锰铜在工频接地及冲击接地性能的区别,结果表明,柔性石墨接地体的工频接地电阻略高于圆钢,但由于其非磁性,较弱的趋肤效应使其冲击接地电阻低于圆钢,因此,柔性石墨接地体具有良好的防雷接地特性。然后,以广东佛山典型输电线路中柔性石墨接地体示范应用工程为例,介绍了有关柔性石墨接地体的实际工程施工工艺及技术,为其他类似的工程及试验提供参考依据。
詹清华 +5 more
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Rare Metals, Volume 45, Issue 6, June 2026.ABSTRACT The poor soft tissue integration around titanium implants creates a microgap that serves as a pathway for pathogen invasion, resulting in infection, inflammation, and the progression of peri‐implantitis. As the implant’s transmucosal component, the abutment determines the degree of peri‐implant soft tissue attachment.
Xuan Li +7 more
wiley +1 more source
Dianci bileiqi, 2020 目前在输电线路杆塔接地网中应用广泛的接地材料包括镀锌扁钢、锰铜等传统金属材料,但在高频电流条件下传统金属接地体存在明显的集肤效应,进而影响其散流特性,新兴的非金属石墨复合接地材料因其"导电不导磁"的特性有效改善了上述问题。针对石墨复合接地体的结构进行优化进而制备了扩径石墨复合接地体,利用有限元仿真分析其集肤效应,并采用CDEGS软件仿真分析传统金属接地体、实心石墨复合接地体及扩径石墨复合接地体在不同频率、不同土壤情况、不同直径条件下的散流特性。研究结果表明,在高频高阻条件下 ...
李文琦 +5 more
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Rare Metals, Volume 45, Issue 6, June 2026.ABSTRACT The urgent environmental crisis caused by polyethylene terephthalate (PET) waste necessitates efficient upcycling strategies. Herein, we establish a novel pathway to transform waste PET plastic into a high‐performance catalytic material for mediating the oxygen evolution reaction (OER). Through a one‐step hydrothermal process, waste PET serves
Xin Wang +5 more
wiley +1 more source
, 2008 提出一种分析管线地基极限承载力的平面应变有限元模拟方法,采用自适应网格技术和接触对算法模拟管线嵌入土体的准静态过程,利用修正Drucker-Prager/Cap本构模型模拟土体塑性。研究不同土性和管土界面摩擦条件下,管线地基土体的塑性变形及位移场特性。利用载荷沉降曲线并结合地基塑性应变分布图和位移矢量图,可判别管线地基的剪切破坏型式 ...
雒承才, 高福平, 赵波
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