Results 11 to 20 of about 731,336 (171)
Jianzhu Gangjiegou Jinzhan为研究碗扣式钢管支撑架不同构造形式节点的转动刚度特性，提出测定支撑架体的角节点、边节点与中间节点转动刚度的试验方案，对应分别插入2根、3根和4根水平杆的节点转动刚度试验。在以相应扣件式节点试验验证方案合理性的基础上，对当地市场随机采购的碗扣式钢管的弹性模量进行测定。采用三折线模型对碗扣式节点的M-θ曲线进行拟合，分析了不同水平杆数目对其转动刚度的影响及其破坏特点。结果表明：（1） 碗扣式钢管支撑架角节点、边节点的转动刚度分别为中间节点的77.93%、92.14%，且均高于规范给出的建议值25 kN·m ...
张金轮, 张阿祥, 王家伟
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High temperature performance of an optical microfibre coupler and its potential use as a sensor [PDF]
, 2012 The dependence of the transmission spectrum of an optical microfibre coupler at high temperatures is investigated experimentally. Results show a temperature sensitivity up to 36.59 pm/°C at a taper waist outer diameter of 2.5 µm; such a temperature ...
Brambilla, Gilberto +6 more
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Wildlife Letters, EarlyView.Asiatic black bears in Russia face conservation threats such as habitat destruction and fragmentation, which exacerbate food shortages caused by crop failures. This study explores an innovative approach to rehabilitating bears that abandon hibernation in mid‐winter due to extreme exhaustion by providing supplemental food near their den sites.
Sergey A. Kolchin +2 more
wiley +1 more source
Functional Ecology, EarlyView.Read the free Plain Language Summary for this article on the Journal blog. Abstract Permafrost thaw is reshaping nutrient dynamics in boreal forests, but its impacts on tree nutrient limitation and functional strategies remain poorly understood. Clarifying these responses is crucial for predicting the response of boreal forests to climate change.
Qiyue Fu +9 more
wiley +1 more source
Inferring alternative ecosystem states with field survey data
Methods in Ecology and Evolution, EarlyView.Abstract Many ecosystems potentially exhibit alternative stable states, where distinct states can coexist under identical environmental conditions. While simulation models have generated key hypotheses in alternative stable states theory, they often rely on scale‐free parameters disconnected from real ecosystems.
Ning Chen +10 more
wiley +1 more source
American Journal of Political Science, EarlyView.Abstract The rise of social media in the digital era poses unprecedented challenges to authoritarian regimes that aim to influence public attitudes and behaviors. To address these challenges, we argue that authoritarian regimes have adopted a decentralized approach to produce and disseminate propaganda on social media.
Yingdan Lu +3 more
wiley +1 more source
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
wiley +1 more source
Drivers of bat researchers’ intent to adopt field hygiene practices
Conservation Biology, EarlyView.Abstract Infectious disease is a growing threat to wildlife, with zoonotic transmission most likely at the human–wildlife interface. One underappreciated activity at this interface is fieldwork with wild animals, but associated risks can be mitigated through field hygiene (FH) practices, such as using personal protective equipment and other appropriate
Joanna L. Coleman +6 more
wiley +1 more source
Advancing conservation breeding programs for marine invertebrates
Conservation Biology, EarlyView.Abstract In the face of ecosystem change and biodiversity loss caused by climate change and other stressors, conservation breeding, or captive breeding, with the aim of reintroduction for wild population recovery, is an emerging tool for preventing species’ extinction and rehabilitating ecosystems.
Elora H. López‐Nandam +3 more
wiley +1 more source
, 2014 非线性方程求根的问题可转化为求不动点的问题,后者常采用迭代法求解.不动点存在唯一性判定定理是其重要定理.通常的不动点存在唯一性判定定理基于Banach不动点定理,需要判定迭代函数是否具备两个条件:映内条件和压缩条件.指出对于非线性方程求根的问题,映内条件可用边界条件代替,并提出改进的不动点存在唯一性判定定理.改进的定理用边界条件取代了映内条件,从而不必考虑迭代函数在整个区间上的情形,而仅需考虑其在区间边界上的函数值,因此更便于应用,且适用范围更广.福建省自然科学基金 ...
晁飞, 施明辉, 周昌乐, 江敏
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