Results 71 to 80 of about 12,334 (149)
Gaoya dianqi, 2013 零件疲劳分析与计算对高压开关设备寿命预测起着至关重要的作用。笔者分析了高压开关传动系统关键零件疲劳的特点;建立了零件疲劳极限应力图模型,采用该模型可以计算出零件的疲劳极限与疲劳安全系数,并且可以估算在考虑安全系数前提下零件的疲劳寿命;以某高压断路器传动连杆的疲劳计算为例,对所采用的方法进行了验证。得出了3点结论:①有必要对高压开关零件进行疲劳分析和计算;②借助零件疲劳极限应力图可以较好地进行零件疲劳强度计算;③应力集中和零件材质对疲劳极限和寿命有较大的影响。
程立 +4 more
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Analysis of spatiotemporal evolution characteristics of floor rock mass and roadway failure under mining influence [PDF]
Clarifying the distribution law of mining induced stress in the working face floor, achieving precise grasp of the degree of damage to the floor rock mass and roadway under the influence of mining, can effectively prevent deformation and instability of ...
Baojie FU +4 more
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Shuitu Baochi Xuebao[目的] 探究三峡库区典型坡地橘园土壤分离能力与集中水流水力学特性参数间的数学关系,为坡地橘园土壤侵蚀预测建模提供理论依据与数据支撑。[方法] 通过集中流冲刷试验,分析在不同坡度(10°~30°)与流量(18~126 L/min)组合的梯度水动力条件下,清耕样地与绿肥(白三叶、早熟禾和野豌豆)覆盖样地的土壤分离量,探讨柑橘园地土壤分离能力与水流动力参数(水流剪切力、水流功率)、流态流型参数(雷诺数、弗罗德数)、阻力参数(Darcy-Weisbach阻力系数、曼宁系数)的定量关系并建立相应的数学模型 ...
张峰玮 +3 more
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Effect of low-temperature ausforming on hydrogen-induced delayed fracture of high-strength bolt steel [PDF]
High-strength bolts are widely used in construction machinery, steel structures, bridges, automobiles, and other industrial sectors owing to their high load-bearing capacity and connection efficiency.
Boyang FANG +5 more
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Shuitu Baochi Xuebao, 2018 为研究灌木植物根系的固土护坡力学效应，探讨根系与土体间相互作用的特性。以多花木蓝为供试植物，进行植物根系切片并计算根系的表面凹凸度，选取0~0.5，0.5~1.0，1.0~1.5,1.5~2.0 mm 4种粒径的粉质黏土，在不同的土体含水率和根径条件下，制备根土复合体扰动试样，进行单根抗拔摩阻试验和直剪摩阻试验，探讨土体含水率、植物根径以及土体粒径对根土界面摩阻特性的影响。结果表明：多花木蓝根系的表面凹凸度随根径变化无显著性差异，根系的拉拔剪应力集中在17.36~32.76 kPa ...
夏振尧, 刘, 饶云康
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Gaoya dianqi, 2020 随着泛在电力物联网的建设,电力输电线路提出了建设智慧输电线路的要求。接续管作为连接导线的重要金具,在振动,热,应力等因素的作用下会发生形变,从而影响输电线路的安全。针对导线接续管形变问题,文中对智慧输电线路接续管状态感知技术进行了研究。首先建立了电容形变模型,分析了电容极板弯曲变形引起的电容变化规律;紧接着,采用有限元方法模拟了接续管形变后的应力,确定了接续管变形值的监测范围;其次,在静电场中对不同变形量的电容进行了仿真,发现了形变量与电容值之间呈二次函数关系;最后,从感知节点 ...
赵隆 +4 more
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Application of microseismic monitoring in the optimization of control strategy for roofs composed of composite hard sandstone masses [PDF]
Objective With a gradual increase in the coal mining depth in China, the movement of overlying thick and hard rock layers exerts increasingly complex impacts on the mine pressure. Methods In the Ordos area, the overburden of the mining face of most mines
Chenchen YANG +5 more
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Study on the stress evolution law of surrounding rock and cooperative control technology in coal seam group mining [PDF]
Aiming at addressing the challenges encountered in roadway support during coal seam group mining, this project focuses on the 212 main return-air cross-cut in Tucheng Mine, Guizhou Province.
Jitao ZHANG +8 more
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Gateroad protection mechanism and surrounding rock control for gob-side entry with slender pillar in deep and inclined extra-thick coal seams [PDF]
The depth of coal mining in the central and eastern China is increasing, the ground pressure is high, the roadway deformation and burst risk is great.
Enyuan DONG +7 more
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Zhongshan Daxue xuebao. Yixue kexue ban, 1988 体外应用RE25-3食管癌细胞系观察了三种维甲类——维甲酸:维胺酯及维胺酸的作用。三种维甲均使细胞的分裂增殖受到抑制,3H-TdR掺入到DNA中减少。染色体数目减少,甚至转化过程中丧失的二倍体重又出现,此外还使细胞的集落形成能力受抑。三者中以维胺酸作用最强;维胺酯与维甲酸相近。
何为民
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