Results 11 to 20 of about 10,138 (118)

地电阻率观测中两种电极接地电阻测量方法及其对比研究

open access: yesDizhen xuebao, 2022
利用传统三极接地电阻率测量方法对井下电极接地电阻进行测量会存在较大的测量误差,表明该方法已不适用于井下电极接地电阻测量。针对此问题,提出了利用台站现有地电阻率仪器进行电极接地电阻测量的新方法—直接测量法,并使用传统三极法和直接测量法对北京平谷地震台井下观测供电电极接地电阻进行了测量。测量结果表明:与传统三极法对比,直接测量法的测量结果更为准确、可靠,而且节省人力、物力和时间。
Yu Zhang, Lanwei Wang, Zhe Hu
doaj   +1 more source

When and why to give shorebirds a head start

open access: yesConservation Biology, EarlyView.
Abstract Headstarting is a translocation technique involving the hatching or rearing of wild eggs or young in captivity and the release of those individuals back to the wild at or before independence. It has been trialed as a conservation intervention for shorebirds over recent decades to improve the population trend of target populations by increasing
Lynda Donaldson   +4 more
wiley   +1 more source

Habitat and spatial trends of U.K. wintering waterbird populations over 50 years

open access: yesConservation Biology, EarlyView.
Abstract The United Kingdom is an important wintering ground for millions of waterbirds. Most U.K. wintering waterbird populations increased between 1970 and the mid‐1990s, but declined thereafter. We examined U.K. population indices in 46 wintering waterbird species in two 25‐year periods, 1970–1994 and 1995–2019, to identify which waterbird groups ...
Blaise Martay   +8 more
wiley   +1 more source

接地极对矩形接地网的降阻效果研究 附视频

open access: yesDianci bileiqi, 2022
接地技术中,在矩形接地网四周顶点敷设接地极是比较常见的优化接地网接地性能的措施。笔者研究了在面积相同的矩形接地网边缘四顶点敷设接地极对接地网的降阻效果,通过改变接地极敷设角度、接地极长度以及分层土壤结构探究接地极对不同长宽比矩形接地网的降阻效果,最后将确定的最佳的敷设方案与常见的垂直敷设方案进行对比。结果表明:按一定角度倾斜敷设接地极对矩形接地网的降阻率可达18%以上;接地极长为1~1.3倍接地网等效半径时降阻效率最高,其单位长度降阻率可达18.5%;对比接地极垂直敷设方案 ...
doaj  

Titanium Implant Abutments With Polydopamine‐Mesoporous Cerium Dioxide Coatings for Enhanced Antibacterial, Anti‐Inflammatory, and Soft Tissue Integration Properties

open access: yesRare 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

直流接地极引起的高速铁路综合接地系统直流电流计算

open access: yesGaoya dianqi, 2022
随着我国高速铁路的广泛延伸,直流接地极与高速铁路相接近的情况时有发生。直流接地极入地电流可能会对高速铁路综合接地系统造成影响。为了评估直流接地极对高速铁路综合接地系统的影响情况,文中建立了高速铁路综合接地系统的直流电流分布的分析模型,获得了高速铁路沿线轴向直流电流分布和单位长度泄漏电流密度分布,说明了直流接地极对高速铁路综合接地系统的电腐蚀影响机理,并分析了土壤电阻率、直流接地极距离等因素对电腐蚀程度的影响。研究结果表明,直流接地极对高速铁路综合接地系统有一定的电腐蚀影响 ...
宋伟   +4 more
doaj  

Upcycling of Waste Polyethylene Terephthalate Plastics to Fabricate Cobalt–Nickel Metal–Organic Frameworks and Their Phosphides for Efficient Oxygen Evolution Reaction

open access: yesRare 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

接地极线路架设方式对单极接地故障下过电压沿线分布的影响

open access: yesDianci bileiqi, 2020
接地极线路的安全稳定运行对整个特高压直流输电系统的可靠性有重要影响。对于通道紧张的输电走廊,接地极线路可与直流输电线路同塔架设。针对不同的直流接地极线路架设方式,研究了接地极线路在单极接地故障下内部过电压的沿线分布规律。结果表明:1)对于单独架设的接地极线路,其内部过电压的幅值从换流站中性母线到接地极址呈近似线性减少的趋势; 2)对于与直流输电线路同塔架设的接地极线路,其内部过电压的沿线幅值分布为非线性,同塔架设段内的过电压可能高于换流站出口处。在进行接地极线路绝缘配合设计时,应考虑接地极线路的架设方式。
雷潇   +5 more
doaj  

Using incentive payments to promote human–carnivore coexistence

open access: yesConservation Biology, Volume 40, Issue 3, June 2026.
Abstract For many large carnivores, minimizing the financial burden they impose on local people is critical to their conservation. Incentive‐based programs that provide people with financial benefits for taking pro‐conservation actions or achieving conservation goals are a promising tool for promoting human–carnivore coexistence. Although the number of
Adam Pekor   +9 more
wiley   +1 more source

输电线路杆塔接地极冲击接地电阻特性分析

open access: yesDianci bileiqi, 2012
为研究雷电流流经输电线路杆塔接地极的冲击特性,运用CDEGS软件仿真分析杆塔接地极在冲击电流作用下的冲击特性。分析水平接地极及四种改进接地极的冲击特性,探讨不同接地极尺寸以及不同土壤电阻率对冲击接地电阻的影响规律。得到接地极长度及半径对水平接地极冲击接地电阻的影响规律,接地极冲击接地电阻随水平接地极长度的增加而降低,但逐渐趋于稳定;同时获得垂直接地极对四种改进接地极的冲击接地电阻特性,为实际工程中采用合适的方法降低杆塔冲击接地电阻提供了参考。
张敏   +6 more
doaj  

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