Results 61 to 70 of about 15,411 (192)
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
Shiyou jixie, 2014 通过对双金属密封结构进行失效分析，得出失效的主要原因是：密封结构内部支撑角度和倒角半径的大小设计不合理导致弹性元件上的应力过大和应力集中，加速了弹性元件磨损和老化。利用有限元分析软件Workbench分析了O形橡胶圈上最大Mises应力和最大剪切应力在不同支撑角度和倒角半径下的分布情况，并对支撑角度和倒角半径进行了优选。分析结果表明，双金属密封结构的支撑角度和倒角大小对O形橡胶圈的应力影响较大；当支撑角度为15°、倒角半径为0.3 mm时，O形橡胶圈最大Mises应力和最大剪切应力最小 ...
肖祥 +4 more
doaj
Transparent exploration technology for hidden disaster-causing factors of geological structure：taking Tunbao Coal Mine in Xinjiang as an example [PDF]
Hidden disaster-causing factors in coal mines are key geological factors that restrict the safety, high efficiency, green and intelligent mining, and transparent geology is an important technical means to realize the detection of hidden disaster-causing ...
Haijun WANG +7 more
core +1 more source
Conservation Biology, EarlyView.Abstract Despite the crucial role of human impacts on biodiversity loss, many assessments of this loss focus on single metrics, such as species richness, and overlook the multidimensional effects of human activities. Because of its importance to ecosystem functioning, we investigated the functional diversity of medium‐ and large‐sized mammal ...
Xueyou Li +8 more
wiley +1 more source
Shuitu Baochi Xuebao, 2018 坡面水流的输沙能力是影响土壤侵蚀过程的重要参数之一，加强坡面集中水流输沙能力的研究有助于深入理解集中流发生机理，并为防治集中流侵蚀发生提供科学依据。采用室内集中流放水冲刷试验，以黄土高原典型黄绵土为研究对象，研究了集中流输沙能力与放水流量和坡度以及与单宽流量和坡度之间的关系，同时对集中流水力参数和输沙能力的相应关系进行了研究。结果表明:集中流输沙能力随着坡度和放水流量的增加而增加。多元统计分析建立输沙能力与坡度和放水流量之间的幂函数关系发现坡度指标对输沙能力相对放水流量影响更大，而在坡度和单宽流量作用下，
师宏强, 谷
doaj
Study on pressure relief effect of multiple mining of protective layer in medium and long distance coal seam group [PDF]
Aiming at the problem that the effect of protective layer mining of medium and long distance coal seam group under complex conditions is not clear, this study takes the coal seam group mining of Shanxi Xinjing Coal Mine as the engineering background, and
Aitao ZHOU +5 more
core +1 more source
Legislating Uncertainty: Election Policies and the Amplification of Misinformation
Policy Studies Journal, EarlyView.ABSTRACT Can state election policies affect the spread of misinformation? This paper studies the role played by ballot processing policies, which determine when ballots can be examined and organized, in the online spread of political misinformation. We present evidence from the 2020 U.S.
Morgan Wack +5 more
wiley +1 more source
Shiyou jixie, 2015 压缩机曲轴在工作中受力情况极为复杂，曲轴作为压缩机最重要的零部件之一，一旦失效将会导致整个压缩机的损坏。鉴于此，以2RDS压缩机曲轴为例，采用INVENTOR三维建模软件建立曲轴模型，使用有限元分析软件ABAQUS对其进行应力分析。分析结果表明，曲轴的应力最大位置均出现在主轴颈-I的油孔处，在曲柄与曲柄销和主轴颈与曲柄销过渡圆角处均出现了应力集中，但是最大应力均小于材料的许用应力，结构不会出现静强度破坏。曲轴在压工况时的受力比拉工况时的受力更加恶劣，应力集中情况更加严重 ...
侯小兵
doaj
Dianci bileiqi, 2022 以三角密封结构在高压复合绝缘子中的密封性能为分析主体，依据应变能理论的数值拟合方法，在试验测试获得密封用橡胶材料力学性能的基础上，对三角密封结构中O形橡胶密封圈的应力及变形进行了非线性仿真分析。首先分析不同压缩率下三角密封结构的应力及变形，得到变形随压缩率的变化规律，预压缩应力随压缩量变大而趋于增大，确定了易发生密封失效的应力集中区域分布于密封圈挤压后的下部左右两侧。然后基于不同气压下三角密封结构的密封性能进行研究，分析了应力集中区域随着内压的增大向作用力一侧移动 ...
doaj
Precursory characteristics and disaster prevention of rock burst in roadway excavation in steeply inclined extra-thick coal seam [PDF]
With the gradual coal mining of deep rock burst mine, the impact accompanying roadway excavation becomes more and more intense. Aiming at the problem of effective prevention and control of rock burst in roadway excavation, taking the steep seam mine in ...
Changliang LU +8 more
core +1 more source