Results 41 to 50 of about 23,510 (147)

The collective application of shorebird tracking data to conservation

open access: yesConservation Biology, EarlyView.
Abstract Addressing urgent conservation issues, such as the drastic declines of North American migratory birds, requires creative, evidence‐based, efficient, and collaborative approaches. The abundance of over 50% of monitored North American shorebird populations has declined by over 50% since 1980. To address these declines, we developed a partnership
Autumn‐Lynn Harrison   +71 more
wiley   +1 more source

棒形抗折试条的统计强度(续)

open access: yesDianci bileiqi, 1981
本文研究未上釉棒形抗折瓷件强度的理论分布,其分布遵循维布尔分布。各种不同因素的试验验证了理论分布的正确性。本文还对估计维布尔参数值的方法进行了讨论,且对大容量子样估计了均匀性系数m在一定置信水平下的置信区间。
马功勋, 刘长荣, 陶增炎
doaj  

Tabular method of calculating Boolean partial derivative and difference of the OC type logic function(计算OC型逻辑函数的布尔偏导数与布尔差分的表格方法)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2007
讨论了OC型逻辑函数一阶布尔偏导数的规范OC展开式.在此基础上提出了计算OC型逻辑函数一阶、二阶布尔偏导数的表格方法.根据二阶布尔差分的定义以及二阶布尔差分与布尔偏导数的关系提出了两种计算OC型逻辑函数二阶布尔差分的表格方法,并作了比较.本文提出的计算OC型逻辑函数布尔偏导数与布尔差分的表格方法具有简捷、方便以及易于计算机编程操作等优点.
LIUGuan-sheng(刘观生)   +2 more
doaj   +1 more source

Informing spatial conservation prioritization with species’ traits

open access: yesConservation Biology, EarlyView.
Abstract New Guinea, the most botanically diverse island on the planet, is the location for one of the boldest conservation initiatives. The Manokwari Declaration aims to achieve 70% conservation designation for the Bird's Head Peninsula. This is 40% higher than the 2022 Global Biodiversity Framework target.
Liam A. Trethowan   +27 more
wiley   +1 more source

330 kV GIS隔离开关操作过程中电磁干扰单脉冲波形特征规律研究

open access: yesGaoya dianqi
气体绝缘开关设备中隔离开关操作产生的特快速暂态过电压是威胁二次设备安全运行的重要因素。为掌握VFTO特征分布规律,文中按照实际线路参数搭建330 kV GIS隔离开关模拟干扰源试验系统,模拟现场GIS隔离开关分合操作时产生的电磁干扰过程,通过核密度估计法对提取的VFTO单脉冲波形特征数据进行了全面的统计分析。结果表明,合、分闸时单脉冲的最大峰值分布呈3峰分布,最大峰值分别分布在[25.98,294.49] kV、[33.08,305.91] kV;合、分闸时的单脉冲的持续时间分布分别呈2峰分布和3峰分布,
梅冰玉   +5 more
doaj  

均压环对复合绝缘子电场分布影响的研究

open access: yesGaoya dianqi, 2006
建立数学模型计算了复合绝缘子的沿面电场分布,利用有限元法计算了220kV线路复合绝缘子不安装均压环及安装不同形状尺寸均压环时沿面场强分布和电位分布。分析了均压环各因素变化对电场分布改善效果的影响,指出环径和罩深对端部电压分布改善效果明显,管径对电场分布改善效果好,根据各因素的综合影响,推荐了220kV复合绝缘子均压环的结构参数。
卫李静   +5 more
doaj  

Differences in characteristics between naturalized threatened plants and other threatened plants

open access: yesConservation Biology, EarlyView.
Abstract Many non‐native plant species introduced by humans have become naturalized. At the same time many species are threatened in their native range. However, the number of plant species threatened in their native range that are naturalized elsewhere remains unknown.
Weihan Zhao   +10 more
wiley   +1 more source

基于多物理场耦合的空气型开关柜发热故障温升仿真分析

open access: yesGaoya dianqi, 2020
空气开关柜是电网中运用最多的开关设备,长期温升过高会导致绝缘性能和机械性能的退化,甚至人员伤亡事故。为分析空气开关柜发热故障的温度分布特性,利用有限元仿真软件建立1∶1模型,进行电磁—流—热多物理场耦合仿真。模拟分析不同热故障,空气开关柜内部气体流速、内部器件表面温度分布、内部温度场分布和外壳温度分布的情况,总结不同热源功率下的分布规律,为基于开关柜表面温度场分布,判定开关柜内部故障奠定理论基础,并提供仿真借鉴。
苏毅   +4 more
doaj  

Comprehensive framework for assessing and optimizing existing research networks

open access: yesConservation Biology, EarlyView.
Abstract Conservation, monitoring, and research networks, or collections of ecological research sites unified under a common mission of data collection or a research mission, are essential infrastructure for understanding large landscapes. However, most networks developed opportunistically over decades rather than through systematic design, creating ...
Alyson East   +2 more
wiley   +1 more source

无间隙金属氧化物避雷器电压分布不均匀系数K值的确定

open access: yesDianci bileiqi, 1990
影响无间隙金属氧化物避雷器电压分布不均匀的主要因素是杂散电容和阀片本身电容的分散。后者往往被忽略,导致不正确的结果。用光纤—电流法测量电压分布不均匀系数K值时,电流分布不能代表电压分布。对一台避雷器的实测结果不能代表同类避雷器电压分布最不均匀的情况。本文提出一种方法,对一台避雷器的实测结果经计算可得出该类避雷器电压分布不均匀系数K的最大值。
张雨时
doaj  

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