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The cross-sectional distortion usually appears during rotary-draw bending process of thin-walled rectangular tube with small bending radius.To study the cross-sectional distortion of the tube,a three-dimensional finite-element model of the process was developed based on ABAQUS/Explicit code and its reliability was validated by experiment.Then,the cross-sectional distortion behaviors of the tube were investigated.The results show that a zone of larger circumferential stress appears on the tube when bending angle reaches 30°.And in the larger circumferential stress zone,the sagging phenomenon is produced obviously.The maximum cross-sectional distortion is located in the larger circumferential stress zone and the angle between the plane of maximum cross-sectional distortion and the bending reference plane is about 50°.The position of the maximum cross-sectional distortion keeps almost unchanged with the variation of the clearances between dies and tube. 相似文献
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油雾润滑系统的应用及存在问题的改进建议 总被引:2,自引:0,他引:2
简要介绍了摩擦的危害,着重阐述了油雾润滑的原理和油雾润滑系统的结构、各部分作用、特点及其使用效果,大量事实证明油雾润滑系统在大型机泵群或多点润滑机械设备群应用经济效益显著。油雾润滑系统具有较高推广和应用价值,提出其在使用中的不足和改进建议。 相似文献
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二连盆地巴音都兰凹陷岩性油藏勘探 总被引:4,自引:1,他引:3
针对巴音都兰凹陷典型的反转型凹陷,构造与有利储集相带不匹配,地震资料品质差等不利因素,通过对构造、层序、沉积、储层等多种控油因素综合地质分析认为,由于构造反转作用,在所形成的大型鼻状或反转背斜构造背景下,阿四段高位体系域进积型扇三角洲沉积于构造的翼部,其前缘砂体夹于湖相暗色泥岩之间,在正向构造的中低部位易形成岩性圈闭。巴Ⅱ号、巴Ⅰ号和包楞构造等翼部为有利靶区,经过多期沉降、多期反转的构造演化,有利于多种类型岩性圈闭的形成,扇三角洲前缘相分流河道砂和次生孔隙发育带控制油气富集。 相似文献
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周口坳陷石炭—二叠系保存较好,面积较大,油气显示普遍。通过对研究区石炭—二叠系的分布特征、圈闭条件、油气成藏期次、油气聚集类型及其成藏控制因素等方面的综合研究,深入探讨了石炭—二叠系的油气成藏条件及其富集控制因素。结果表明,“古生新储”型是倪丘集地区重要的油气聚集类型;周口坳陷多期构造活动形成了多类型的构造圈闭;下古生界碳酸盐岩顶部风化壳为岩溶地貌圈闭的形成创造了良好条件;上古生界海陆交互相煤系地层为地层-岩性圈闭的形成打下了基础;印支期和喜马拉雅期是石炭—二叠系最重要的油气生成和运聚期,并存在“自生自储”、“下生上储”和古潜山型3种油气聚集类型;石炭—二叠系油气成藏的控制因素主要有效烃源岩的分布、输导体系的输导能力、圈闭定型期和油气运聚期的有效配置以及古近纪构造格局。研究区石炭—二叠系资源潜力较大,成藏条件有利,富集规律明显,是寻找大中型油气田的有利地区。 相似文献
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CHENG Wen Environment Research Institute Xian University of Technology Xi 'an China State Key Laboratory of Multiphase Flow in Power Engineering Xi 'an Jiaotong University Xi 'an China HU Bao-wei Key Laboratory of Northwest Water Resources Environmental Ecology of Education Ministry Xi 'an University of Technology China Yuanpei College Shaoxing University Shaoxing China YANG Chun-di Yuanpei College China CHENG Wen-juan Environment Researc... 《水动力学研究与进展(B辑)》2010,22(2):260-264
Aeration is an important factor affecting the biological aeration filter. With a set of experiment device specially designed for the purpose, and the particle image velocimetry technique, the velocity field of the gas-liquid two-phase flow is studied under different conditions. The various simulated aeration states were actually applied to the experimental device of sewage treatment, and the results of the numerical simulation were verified. The final experimental results indicate that the most efficient state occurs when the ratio of water in aeration tank h/w=1, the diameter of capillary tubes d=0.6mm and the velocity of bubbles v=0.3m/s. 相似文献
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SHI Xiaoqi ZOU Ming JIANG Mingxue College of Materials Science Engineering Xi 'an University of Architecture & Technology Xi 'an China 《中国耐火材料》2008,17(4)
TIN-Al2O3 composite powders with different TiN contents (0,10 vol%,20 vol%,30 vol% and 40 vol%) were prepared with micrometer TiN and α-Al2O3 powder (their purities were 99%) as starting materials by wet ball milling for 5 h.TiN-Al2O3 com-posite were then prepared by pressing the above composite powders,drying at 200 ℃ for 12 h and firing at 1 800 ℃ for 3 h in nitrogen atmosphere in hot-pressing furnace.The influences of TiN content on mechanical properties and electrical conductivity of TiN-Al2O3 com-posites were studied.The results showed that the me-chanical properties of the composite increased with TiN content increasing,while the resistivity of composites de-creased.A composite with 40% TiN had 498 MPa ben-ding strength,4.285 MPa·m1/2 fracture toughness,1.34×10-3 Ω·cm resistivity.The SEM analysis showed that the fine TiN crystals distributed among the crystal boundary of Al2O3 matrix.They bonded together forming a net-like structure which played a role of re-straining Al2O3 grains from growing up,toughening and strengthening,so the mechanical properties of TIN -Al2O3 composite were enhanced. 相似文献