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991.
基于约束混凝土提出一种由钢筋、混凝土及缠绕管组成的内置复合材料管局部约束混凝土组合柱(ConcreteEncased FRP Confined Concrete Sub-Columns/Cores Column,简称"CEFC"),本构件截面形式为外围的钢筋混凝土类方柱和内置于4角点的FRP管约束混凝土圆柱(Concrete-Filled FRP Tube,简称"CFFT")组合而成。通过试验研究及有限元数值模拟对钢筋混凝土柱及内置复合管局部弱约束混凝土方柱进行了轴偏压作用下力学行为的分析和比较。结果表明,弱约束CEFC典型破坏模式为局部破坏,内置CFFT可较好延缓构件整体破坏。CEFC在轴压和偏压作用下延性都有所提高,且在偏压作用下CEFC具有明显的二阶刚度,且承载力具有小幅度提高。 相似文献
992.
Increased HDL Size and Enhanced Apo A-I Catabolic Rates Are Associated With Doxorubicin-Induced Proteinuria in New Zealand White Rabbits 下载免费PDF全文
Victoria López-Olmos Elizabeth Carreón-Torres María Luna-Luna Cristobal Flores-Castillo Miriam Martínez-Ramírez Rocío Bautista-Pérez Martha Franco Julio Sandoval-Zárate Francisco-Javier Roldán Alberto Aranda-Fraustro Elizabeth Soria-Castro Mónica Muñoz-Vega José-Manuel Fragoso Gilberto Vargas-Alarcón Oscar Pérez-Méndez 《Lipids》2016,51(3):311-320
The catabolism and structure of high‐density lipoproteins (HDL) may be the determining factor of their atheroprotective properties. To better understand the role of the kidney in HDL catabolism, here we characterized HDL subclasses and the catabolic rates of apo A‐I in a rabbit model of proteinuria. Proteinuria was induced by intravenous administration of doxorubicin in New Zealand white rabbits (n = 10). HDL size and HDL subclass lipids were assessed by electrophoresis of the isolated lipoproteins. The catabolic rate of HDL‐apo A‐I was evaluated by exogenous radiolabelling with iodine‐131. Doxorubicin induced significant proteinuria after 4 weeks (4.47 ± 0.55 vs. 0.30 ± 0.02 g/L of protein in urine, P < 0.001) associated with increased uremia, creatininemia, and cardiotoxicity. Large HDL2b augmented significantly during proteinuria, whereas small HDL3b and HDL3c decreased compared to basal conditions. HDL2b, HDL2a, and HDL3a subclasses were enriched with triacylglycerols in proteinuric animals as determined by the triacylglycerol‐to‐phospholipid ratio; the cholesterol content in HDL subclasses remained unchanged. The fractional catabolic rate (FCR) of [131I]‐apo A‐I in the proteinuric rabbits was faster (FCR = 0.036 h?1) compared to control rabbits group (FCR = 0.026 h?1, P < 0.05). Apo E increased and apo A‐I decreased in HDL, whereas PON‐1 activity increased in proteinuric rabbits. Proteinuria was associated with an increased number of large HDL2b particles and a decreased number of small HDL3b and 3c. Proteinuria was also connected to an alteration in HDL subclass lipids, apolipoprotein content of HDL, high paraoxonase‐1 activity, and a rise in the fractional catabolic rate of the [131I]‐apo A‐I. 相似文献
993.
溢流式球磨机是选矿分厂矿石细碎的主要设备,其进料部空心轴衬套多次出现固定螺栓断裂、衬套外窜,导致润滑油污染。分析引起衬套损坏的原因,介绍所采取的对策,即改变衬套的部分材质、增加内六方螺栓固定连接等。改造后空心轴衬套运行效果较好,泄漏率大大降低。 相似文献
994.
Xiaoyu Ding Jianhua Liu Tequila A. L. Harris 《American Institute of Chemical Engineers》2016,62(7):2508-2524
Slot die coating is a pre‐metered process commonly used for producing thin and uniform films. It is an important film fabrication method for applications where precise coating is required. A major concern in slot die coating processes is how to determine the operating limits to set the appropriate range of operating parameters, including coating speed, flow rate, vacuum pressure, coating gap, liquid viscosity and surface tension, etc. Operating limits directly determine the effectiveness and efficiency of the process. In this article, the current state of academic research on operating limits in slot die coating processes is reviewed. Specifically, the theories, mechanisms, and empirical conclusions related to the limits on vacuum pressure, the low‐flow limit, the limit of wet thickness for zero‐vacuum‐pressure cases, the limit of dynamic wetting failure, and the limits of coating speed for a specific flow rate are reviewed. The article concludes with some recommendations for future work. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2508–2524, 2016 相似文献
995.
The effect of through thickness reinforced open-hole laminates was analysed in terms of laminate behaviour under in-plane tensile loading based on continuum mechanics. Stitches around the notch were oriented in the longitudinal and transverse directions. To obtain the macroscopic damage and the local stress–strain constitutive behaviour, laminates were modelled on a lamina-wise basis. Interfaces between lamina and stitch yarns were assumed to be perfectly glued and modelled by the contact capability. Discretisation procedures using the principle of virtual work were applied in addition to discretisation of the contact traction. Progressive failure analysis with Puck’s failure criteria was conducted to characterise the failure behaviour of the laminate. In both cases, damage was initiated by a matrix crack in the perpendicular direction of the loading axis on the notch. The longitudinally stitched laminate showed a 14.29% higher strength compared to the transversely stitched laminate by suppressing damage propagation. The results obtained using this finite element technique was consistent with the experimental results. 相似文献
996.
基于有限元的轮胎疲劳寿命评价方法,建立295/80R22.5全钢子午线轮胎的有限元模型。使用ABAQUS隐式分析方法获得轮胎的应变、应力以及应变能密度等基本参数后,根据轮胎实际使用中的破坏情况选择影响疲劳寿命的评价指标。结果表明:高速耐久工况下,应选择应变能密度和帘线张力作为影响疲劳寿命的评价指标,而且适当增加带束胶厚度能有效提高轮胎的疲劳寿命;低速重载工况下,应当选择帘线和橡胶间的剪应力(层间剪应力)作为影响疲劳寿命的评价指标,且适当降低胎体帘布层和补强层的高度能有效提高轮胎的疲劳寿命。 相似文献
997.
Effect of pin rotating speed on lap shear strength of stationary shoulder friction stir lap welded 6005A-T6 aluminum alloy 下载免费PDF全文
Stationary shoulder friction stir lap welding (SSFSLW) was successfully used to weld 6005A-T6 aluminum alloy in this paper.Effect of pin rotating speed on cross section morphologies and lap shear strength of the SSFSLW joints were mainly discussed.Results show that joints without flash and shoulder marks can be obtained by the stationary shoulder.Cross section of the SSFSLW joint presents a basin-like morphology and little material loss.By increasing the rotating speed from 1 000 rpm to 1 600 rpm,both effective sheet thickness and lap width increase,while lap shear failure load firstly decreases and then increases.The maximum failure load of 14.05 kN is attained when 1 000 rpm is used.All SSFSLW joints present shear fracture mode. 相似文献
998.
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1000.
以故障总时间法对国外高档加工中心的故障数据进行了数据处理,并应用Matlab软件对故障数据进行了包括模型选择、参数估计和校验等可靠性统计分析,得到了加工中心的故障数据服从二参数威布尔分布。并基于所得到的各种可靠性指标对此加工中心进行了可靠性评价。 相似文献