Results 31 to 40 of about 1,275,212 (147)
Evaluating protected areas’ coverage of threats to terrestrial biodiversity
Conservation Biology, Volume 39, Issue 6, December 2025.Abstract Protected areas (PAs) are vital for biodiversity conservation and have expanded globally. However, increasing pressures on biodiversity make it difficult to achieve conservation goals. Using threat probability maps based on the International Union for Conservation of Nature Red List and the World Database of Protected Areas, we analyzed the ...
Katherine Pulido‐Chadid +2 more
wiley +1 more source
Conservation Biology, Volume 39, Issue 6, December 2025.Abstract Pollinator conservation schemes typically focus on conserving existing, restoring degraded, or creating new wild bee habitats. Their effectiveness depends on dispersal corridors enabling habitat colonization by bees. However, the role of seminatural linear landscape structures (LLS) in connecting pollinator communities across intensively ...
Markus A. K. Sydenham +6 more
wiley +1 more source
Jianzhu Gangjiegou Jinzhan, 2021 对采用钢板攻丝高强螺栓连接的钢框架节点分别进行了高强螺栓拉伸及剪切试验、钢柱法兰连接节点静力及拟静力试验、梁柱半刚性连接静力试验。基于试验数据对节点连接的承载能力、失效模式以及刚度特征等关键问题进行了分析。研究结果表明:由自攻螺纹钢板及高强螺栓构成的连接形式具有良好的抗拉、抗剪性能,以螺杆断裂为最终破坏模式;钢柱法兰连接中法兰板无明显滑移及翘曲,高强螺栓没有拔出或断裂,试件表现出较好的延性和承载能力;梁柱连接表现出典型半刚性特征,桁架梁先于节点域发生破坏,破坏特征为桁架弦杆屈服及斜腹杆屈曲,节点连接符合"
贾斌 +4 more
doaj
The configurational transition of polyelectrolyte chain confined in a cylinder(聚电解质链在柱状受限下的构象转变)
Zhejiang Daxue xuebao. Lixue ban, 2023 采用粗粒化分子动力学模拟方法，研究了受限于圆柱体内的聚电解质链的构象行为。通过计算链平均回旋半径、平均持久长度和平均形状因子等物理量，重点探究反离子价态、链刚性和受限孔径等对聚电解质链尺寸和构象转变的影响。结果表明，受限聚电解质链可形成稳定的棒状、球状、折叠链状和环状结构。尤其在三价反离子诱导下，半刚性聚电解质链可形成稳定的环状结构，并由切向相关函数表征。通过统计反离子分布，进一步探讨了聚电解质链和离子凝结的机制。同时讨论了环的成核和生长动力学特征 ...
高菊先(GAO Juxian) +2 more
doaj +1 more source
, 2017 针对采用半刚性节点连接的双肢冷弯薄壁C形钢框架,采用拟静力试验与有限元模拟相结合的方法,对9榀双层单跨框架进行抗震性能分析。分析了节点螺栓直径、节点板厚度、螺栓间距及节点板加腋大小等参数对框架抗震性能的影响。结果表明:增大螺栓直径、增加节点板厚度和节点板加腋均能提高框架的承载力,改善框架的抗震性能。当螺栓间距小于80mm时,框架的承载力及抗震性能随间距的增大而增大;当螺栓间距大于80mm时,承载力及抗震性能受其影响较小。使用8.8级M16高强度螺栓,框架节点板产生了较大的滑移 ...
陈明, 陈亚栋
core +1 more source
Jianzhu Gangjiegou Jinzhan, 2012 为了研究混凝土翼板外伸锚固的梁柱端板连接半刚性组合边节点力学性能,设计了3个足尺试件,其中两个混凝土翼板外伸150mm,厚度分别为140mm和200mm;另外一个为混凝土翼板未外伸的对比试件。采用柱顶水平位移控制低周循环加载试验,分析了锚固对该半刚性组合边节点力学性能的影响。结果表明,混凝土翼板外伸锚固（尤其是外伸锚固部分加厚）能够提高该半刚性组合边节点的稳定性及其抗震能力。因此,在实际施工中,应该尽可能锚固。
黄兴, 叶志明, 石文龙
doaj
Jianzhu Gangjiegou Jinzhan, 2020 T形件作为半刚性钢框架梁柱节点连接的重要组件,其初始刚度对节点刚性的影响至关重要。目前,尚缺乏对圆钢管混凝土柱高强单边螺栓T形件初始刚度计算的研究。采用欧洲规范EN 1993-1-8中的组件法,以圆钢管混凝土柱高强单边螺栓T形件为对象,通过简化力学模型,分别给出了弧形端板的抗弯刚度、圆形柱翼缘壁的抗弯刚度、螺栓的抗拉刚度以及锚固钢筋的抗拔刚度计算公式。利用有限元软件ABAQUS,通过数值分析确定了重要影响参数,给出了可用于计算的系数曲线。提出了圆钢管混凝土柱高强单边螺栓T形件的初始刚度计算方法 ...
王静峰 +4 more
doaj
Using online reports of seahorse seizures to track their illegal trade
Conservation Biology, Volume 39, Issue 5, October 2025.Abstract Illegal wildlife trade (IWT) is a persistent and extensive threat to global biodiversity. Hundreds of marine fish species are subject to regulation under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), but it is unclear how much protection species gain from CITES because information on marine fish ...
Sarah J. Foster +3 more
wiley +1 more source
Jianzhu Gangjiegou Jinzhan, 2010 传统的设计和分析都将框架的梁柱节点处理成理想的刚接或铰接。然而,实际工程中的连接一般很难达到这两种理想状态,大部分连接的受力性能介于这两者之间,为半刚性连接。在组合框架中,组合楼板和纯钢梁柱端板连接节点组成了一种新的连接形式-半刚性组合连接。针对我国目前还没有关于平端板连接梁柱组合节点设计规定的现状,基于现有的研究成果,本文提出了平端板连接半刚性组合节点设计的方法和建议,可为我国相应规范的修订提供参考。
刘秀华, 巢沧海, 石文龙
doaj
A global indicator of species recovery
Conservation Biology, Volume 39, Issue 5, October 2025.Abstract Monitoring progress toward meeting global biodiversity goals involves several indicators, including, at the species level, the International Union for Conservation of Nature (IUCN) Red List Index (RLI) and the Living Planet Index (LPI). However, at present, there is no indicator specifically for tracking species recovery, despite this being ...
H. Resit Akçakaya +4 more
wiley +1 more source