Results 41 to 50 of about 28,511 (200)
Research on dynamic properties of a cable-truss pre-stressed dome(索-桁预应力穹顶结构的动力性能研究)
Zhejiang Daxue xuebao. Lixue ban, 2003 索-桁结构是一种有潜力的空间结构,但目前的研究尚不够深入.本文提出了一种圆形平面索-桁预应力结构,采用反应谱法和时程法分析,研究了其动力性能.结果表明,该种结构的频谱极为密集,振型较为复杂;这类结构采用反应谱法计算动内力将导致不可接受的误差,而应采用相应的时程分析法计算动内力.同时还得出了这种结构预应力的施加不可缺少,否则将有可能导致动力破坏的结论.
GAOBo-qing(高博青) +1 more
doaj +1 more source
Conservation Biology, EarlyView.Abstract Prioritization in conservation is crucial for the development of efficient and effective decision‐making policies. For many decades, the importance of some species and their habitats has been assessed and applied in conservation legislation, but bats and their diurnal roosts have ofbeen overlooked.
David López‐Bosch +6 more
wiley +1 more source
Zhongshan Daxue xuebao. Yixue kexue ban, 2000 【目的】了解磁性固位的下颌种植覆盖义齿的应力状况及其分布规律, 为磁性固位体的临床应用提供生物力学 依据。【方法】采用二维光弹应力分析法, 分析圆柱形种植体在垂直向和侧向加载条件下种植体— 骨界面的应力状况。【结 果】种植体应力主要为均匀分布的压应力, 最大应力位于种植体根尖部, 颈部应力相对较小, 未见明显弯曲应力。【结论】磁 性固位种植义齿的种植体应力分布符合生物力学要求, 有利于种植体的长期成功。
魏素华 +3 more
doaj
Conservation Biology, EarlyView.Abstract Consumer demand for ivory perpetuates the unsustainable and illegal killing of African elephants and other wildlife species. Interventions that aim to change consumer behavior are increasingly recognized as a crucial element of demand management. However, poor design and implementation have limited their effectiveness.
Molly R. C. Brown +2 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
Shiyou jixie, 2015 针对三高气田套管腐蚀难题，分析了套管腐蚀失效因素，设计了应力腐蚀试验方法。用TP110TS和TP95S套管试样，模拟现场井下条件进行不同拉应力、无应力和压应力状态下套管腐蚀试验，并根据试验结果对套管应力腐蚀速率的主要影响因素、腐蚀后力学性能、应力腐蚀敏感性和应力腐蚀门槛值及安全性进行研究。研究结果表明，三高气田套管腐蚀不可避免，拉应力对应力腐蚀具有敏感性；随着拉应力、H2S和CO2含量的增大，套管腐蚀速率加快、力学性能退化，导致其服役安全寿命缩短。据此提出了采用组合套管 ...
黄洪春, 沈忠厚, 高德利
doaj
Conservation Biology, EarlyView.Abstract Wildlife reintroductions are socioecological processes entailing the intentional movement of organisms by people. In animal reintroductions, there is growing recognition of the importance of human dimensions and efforts to integrate these into reintroduction projects. To conceptually reframe reintroductions as processes of renewed coexistence (
Roger Edward Auster +3 more
wiley +1 more source
Jianzhu Gangjiegou Jinzhan, 2015 对铰接半刚性结构找形、找力分析,提出一种精确的非线性有限元方法.分两步建立找形与找力分析迭代公式。第1步:基于荷载态节点坐标、预应力态节点坐标及预应力态单元预应力,建立荷载态结构非线性平衡方程,根据矩阵微分理论、Newton切线法概念和边界条件求解荷载态结构非线性平衡方程,从而得到预应力态节点坐标迭代公式;第2步:基于预应力态节点坐标、零态节点坐标和预应力态单元预应力,建立预应力态结构非线性平衡方程,同样根据上述理论和概念以及边界条件求解预应力态结构非线性平衡方程,从而得到零态节点坐标迭代公式 ...
刘树堂
doaj
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
Dizhen xuebao利用双差定位法对2010年8月1日至2014年12月31日福建仙游地区中国地震台网中心记录到的地震群进行重定位，并采用P波初动的方法求解出该震群的159个震源机制解，显示该震群的震源机制解结果与背景构造应力场表现明显不一致。为了进一步探究差异性存在的原因，将得到的震群震源机制解结果分区域和分深度求解应力场，结果显示：金钟水库的东南部附近应力方向更远离背景构造应力方向，并且应力形因子小于0.5，中间轴呈现为拉张应力；随着深度的增加，应力场的方向也更接近背景构造应力场的方向。此外 ...
Hailin Yu +4 more
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