Results 21 to 30 of about 417,531 (176)

多级电涌保护器对负载有效性试验分析

open access: yesDianci bileiqi, 2014
针对多级电涌保护器(SPD)安装在电源线路时可能对负载电压起到抑制作用,而导致SPD达不到预期的有效性保护的问题,通过组合波发生器(1.2/50μs、8/20μs)模拟雷电流,对负载分别为阻性、容性、感性时,特性阻抗值相同、长度不同的RVVP电缆做冲击试验,研究负载与RVVP电缆特性阻抗匹配关系及波电缆中的折反射现象,分析电缆的长度与不同特性负载的关系,得出当负载为阻性时,多级电涌保护器的有效防护距离与电阻值呈负相关;当负载为容性时,多级电涌保护器的有效防护距离与电容值呈先负相关后正相关;当负载为感性时,
周中山   +4 more
doaj  

长江枯水期石首麋鹿的生境选择

open access: yes野生动物学报, 2020
麋鹿属于国家Ⅰ级保护动物,对麋鹿种群在枯水期江滩湿地的生境选择特征进行调查分析,可为麋鹿种群的保护与管理提供科学依据。2017年秋季至2019年春季,运用种群生态学、行为生态学等研究方法,调查并比较了48个利用样方与41个对照样方,分析了石首麋鹿在长江枯水期的生境选择。研究表明,对长江枯水期麋鹿生境选择起到重要作用的关键因子分别为扰动因子、水源因子和隐蔽因子。长江枯水期麋鹿生境选择资源函数为:z=-0.518+1.672×人为干扰距离-0.186×水源距离-2.463×道路距离+0.224×隐蔽度-0 ...
张怀胜 1   +4 more
doaj  

Life Stage‐Specific Genetic Diversity and Landscape Characteristics Collectively Influence Genetic Recovery in Pometia pinnata Population 生活史阶段特异的遗传多样性与景观特征对番龙眼种群遗传恢复的协同影响

open access: yesIntegrative Conservation, Volume 5, Issue 1, Page 137-149, March 2026.
Pometia pinnata demonstrated life‐stage‐specific genetic responses to landscape features, with asymmetric gene flow patterns and population recovery following historical bottlenecks, revealing complex topographic and demographic influences on forest genetic structure.
Madhuparna Chatterjee   +5 more
wiley   +1 more source

Landscape Composition and Proximity to Water Affect American Badger Occupancy in Shortgrass Prairies 景观组成和与水的距离影响矮草草原中美洲獾的占域率

open access: yesWildlife Letters, Volume 4, Issue 1, Page 23-31, March 2026.
American badgers, a medium‐sized carnivore occurring in much of North America, are important predators in prairie landscapes though our understanding of their habitat use requirements in these areas is unclear. We used a multi‐scale approach to understand American badger habitat use at both local and landscape scales.
Colleen W. Piper   +5 more
wiley   +1 more source

一种计及雷电入射角的改进电气几何模型

open access: yesDianci bileiqi, 2017
以暴露距离作为计算手段的电气几何模型存在雷电入射方向固定以及难以适用于输电线路小保护角等缺点。为此,改进雷电入射方式,将雷电入射方向扩大至[-p/2,p/2],并推导出不同雷电入射角下的暴露距离计算方法。以输电线路小保护角为例,传统方法与改进方法计算得到的绕击跳闸率分别为0.021 7、0.088 1次/(100 km·a),对造成差异的原因从雷电入射概率和暴露距离两方面进行分析。分析表明,改进方法雷电入射概率为57.33%,小于传统模型;但其暴露距离在5.0 m左右波动,大于传统模型的1.35 m ...
龚磊, 郭恒
doaj  

Spatial segregation and bycatch risk as potential drivers of population trends of wandering albatrosses at South Georgia

open access: yesConservation Biology, Volume 40, Issue 1, February 2026.
Abstract Spatial segregation in at‐sea distribution is frequently observed in seabirds and can have important implications for conservation and management. Globally, many albatross and petrel populations are declining due to bycatch in fisheries. In South Georgia, the decrease in wandering albatrosses (Diomedea exulans) differs among breeding sites ...
V. Warwick‐Evans   +3 more
wiley   +1 more source

500kV避雷器保护距离试验及对热备用断路器距离保护效果分析

open access: yesDianci bileiqi, 2015
首次开展了对500 kV避雷器保护距离的模拟试验,得出了避雷器对被保护设备的保护效果随保护距离的增大而减小的结论,并根据试验结果拟合了关系曲线。同时,考虑到变电站或换流站遭受多次雷击后受避雷器保护的断路器处于热备用状态的情况,进行了断路器热备用状态下避雷器对其保护范围的计算分析,并选取地处雷电频繁区贵州的兴仁换流站为例,仿真分析了当站内交流侧被保护断路器处于热备用状态下,不同雷击下避雷器对其的保护范围及保护效果,得出了避雷器保护范围受不同因素影响的具体情况。
邱慧敏
doaj  

Effects of organized guarding on mortality from human–elephant conflict in northeast India

open access: yesConservation Biology, Volume 40, Issue 1, February 2026.
Abstract Human–elephant conflict (HEC) frequently results in human and elephant mortality, posing major social justice and conservation concerns across Asia and Africa. Although a variety of interventions have been introduced to mitigate HEC, rigorous evaluations of how they affect mortality are practically nonexistent.
Nitin Sekar   +6 more
wiley   +1 more source

基于冲击试验的低压系统SPD有效保护距离分析研究

open access: yesDianci bileiqi, 2018
针对电涌保护器(SPD)动作时可能对负载电压起到抑制作用而导致SPD无法达到预期的有效性保护的问题,本文通过混合波发生器模拟雷电流,对负载分别为阻性、容性时,特性阻抗值相同、长度不同的RVVP电缆做冲击试验,研究负载与RVVP电缆特性阻抗匹配关系及波电缆中的折射反射现象,分析不同长度RVVP电缆与不同特性负载的关系。得出当负载为阻性时,电涌保护器的有效保护距离与电阻值呈负相关;当负载为容性时,电涌保护器的有效保护距离与电容值呈正相关。
李顺昕, 朱正甲, 李岩峰
doaj  

Identifying potentially suitable and accessible refugia to mitigate impacts of an emerging disease on a rare tree

open access: yesConservation Biology, Volume 39, Issue 6, December 2025.
Abstract Identifying refugia from emerging threats is vital to ensure the persistence of rare and threatened species, but modeling habitat distribution for these species is challenging and the role of people in refuge management is rarely considered. Myrtle rust is an emerging infectious disease that represents a grave threat to the rare wetland tree ...
Sarah M. Herbert   +7 more
wiley   +1 more source

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