Results 21 to 30 of about 586,100 (219)
The collective application of shorebird tracking data to conservation
Conservation 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
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Dizhen xuebao, 2019 利用区域应力张量阻尼方法，使用南北地震带及其邻近区域2009年1月—2017年8月466次ML≥3.5地震的震源机制解，及1976年1月—2017年8月GCMT公布的259次M≥4.5地震的震源机制解，反演得到研究区1.0°×1.0°网格大小区域的构造应力场。应力场空间分布特征显示，南北地震带作为青藏高原的东边界，由于所处动力环境复杂，其内部最大主应力方向具有明显的空间差异性。这种差异主要表现为：南北地震带北段最大主应力方向为NE向；南北地震带中段及周边除龙门山断裂带NE段最大主应力为NW-NNW向外 ...
Zijian Cui +3 more
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Comprehensive framework for assessing and optimizing existing research networks
Conservation 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
Jianzhu Gangjiegou Jinzhan, 2021 中空夹层圆钢管混凝土短柱在轴压作用下,混凝土材料受到内外钢管约束处于三向受压状态,其抗压承载力较普通混凝土有较大提升。提升幅度与侧压应力有直接关系,侧压应力大小取决于截面尺寸及其所受轴力。现行设计方法认为同一构件在轴压和纯弯状态下侧压应力大小相同,对于偏压状态下的侧压应力如何考虑未明确说明。对此,引入与轴力相关的侧压应力系数β修正混凝土的本构关系,明确在各种受力状态下如何考虑侧压应力的影响。还提出一种应力积分算法用于计算短柱构件的极限承载力,得到短柱截面的轴力-弯矩(N-M)曲线。最后 ...
谌扬宇 +4 more
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Conservation Biology, EarlyView.Abstract The design of experiments to investigate the combined effects of multiple stressors requires exposing target organisms to multiple combinations of stressor doses. Concurrent manipulation of stressors is often infeasible with wildlife, but long‐lasting health effects allow individual health to be used as an integrator of prior stressor exposure.
Enrico Pirotta +24 more
wiley +1 more source
Conservation Biology, EarlyView.Abstract Constructed value of information (CVoI) is an expert elicitation decision‐analytic tool used to prioritize sources of uncertainty based on their potential to improve decision outcomes if resolved. Despite increased application of CVoI, the robustness of CVoI prioritization of sources of uncertainty relative to differences in expert elicitation
Kristin P. Davis +7 more
wiley +1 more source
Gaoya dianqi, 2010 影响电子设备正常工作的浪涌分量主要集中在低频部分,但小部分高频分量也具有较强干扰性。将压敏电阻与低通滤波器结合起来的滤波式浪涌抑制器,既能控制浪涌低频分量,又能抑制高频干扰。笔者采用Matlab软件对电路受到1.2/50μs冲击电压波后的响应进行了仿真,给出了不同类型和大小的负载对滤波式浪涌抑制器保护效果的影响分析,指出在实际应用中滤波式浪涌抑制器既要考虑低通滤波器的类型与其参数选择,还要兼顾滤波器与负载阻抗的匹配。
应力恒
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Gaoya dianqi, 2020 GIS盆式绝缘子的静力特性问题是盆式绝缘子制造和运维中的关键问题。文中建立了252 kV正常或含有缺陷盆式绝缘子的三维模型,采用有限元法计算了盆式绝缘子在不同气室压力、不同裂纹大小和不同母线温度下应力分布特性。研究结果表明,当盆式绝缘子两侧气室压力均为0.4 MPa时,最大应力为1.3 MPa,最大应力点为外法兰和绝缘子本体交界面附近。若下表面气室压力为0.1 MPa时,最大应力为12.3 MPa;若上表面气室压力为0.1 MPa时,最大应力为10.9 MPa,但均未超过环氧树脂的屈服强度40 MPa ...
高晋文 +5 more
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疲劳荷载特性对8.8级M24高强度螺栓疲劳裂纹扩展机理影响探析
Jianzhu Gangjiegou Jinzhan, 2023 为研究常幅疲劳荷载特性对高强度螺栓疲劳裂纹扩展的影响，针对钢结构端板连接用8.8级M24高强度螺栓在不同应力比/应力幅作用下常幅疲劳试验所得到的24个试件断口形貌进行定量分析，并采用ABAQUS软件数值模拟高强度螺栓应力集中情况，探讨含初始裂纹高强度螺栓裂纹尖端应力强度因子与荷载特性、预制裂纹形状之间的关系。结果表明：在轴向受拉疲劳荷载作用下，螺母与螺栓啮合第1圈螺纹处为疲劳断裂最不利位置；试件断口稳定扩展区面积与应力比/应力幅呈负相关，快速扩展区面积与应力比/应力幅呈正相关 ...
樊丽轩 +4 more
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, 1958 本文分析了扭矩和內压复合加載下的黄铜薄管試驗結果。試驗变形范圍屬小彈塑性。加載方式包括簡單加載,应力分量无一减少的复杂加載,以及“中性变載”。分析对象包括应力与应变主軸方向間的关系,应力与应变Lode参数间的关系以及硬化特性曲綫的建立。試驗結果示出:在各种加載方式中,应力应变关系都大致符合流动理論。而在应力分量无一减少的复杂加載中,形变理論也能大約适用。但在“中性变載”中,形变理論的各項基本假定与实验数据有显著差异,因而不能适用。对于“中性变載”,滑移理論所預測的应变数值也与实驗数据有較显著的不符 ...
杨南生
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