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黄河二桥的照明设计实现了从设计立案、试验定案、施工调整到竣工的全过程。对于桥梁装饰照明做了一次很好的尝试,在保证交通功能免受干扰的前提下,展现了桥梁作为夜间景观的意义。 相似文献
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MWCNTS/SiC composites were fabricated by aqueous tape casting. High solid content (50 vol%) SiC slurries with sintering additives and multi-wall carbon nanotubes (MWCNTs) as reinforcements were prepared using Tetramethylammonium hydroxide as the dispersant. The stability of MWCNTs/SiC slur-ries was studied and characterized in terms of zeta potential and rheology measurements. The relative density of the composite was about 98% after hot-pressing at 1850℃ (at 25 MPa in Ar for 30 min). The hardness of the composites decreased with the increase in MWCNTs content. The flexural strength and the fracture toughness were 742.17 MPa and 4.63 MPa·m1/2, respectively when the MWCNTs content was 0.25 wt%. Further increase in MWCNTs content to 0.50 wt% did not lead to the increase in mechanical properties. Most of MWCNTs were found to be located at SiC grain boundaries and the pull out of the MWCNTs was observed. 相似文献
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回转窑液压挡轮的应力强度与疲劳断裂分析 总被引:2,自引:2,他引:0
运用有限元技术对一台大型沥青焦回转窑设备中发生断裂事故的液压挡轮部件进行强度失效分析及疲劳寿命估算.通过断口形貌分析和金相实验,得出失效机理为疲劳断裂的定性结论.利用Ansys软件建立挡轮的有限元模型,计算出应力和变形等一系列结果.在确定交变应力幅值及裂纹尖端应力强度因子的基础上,利用Paris公式预算含缺陷挡轮的疲劳寿命.在选材及造型设计上对挡轮提出改进方案,将韧性较差的铸钢材料替换为韧性较好的锻钢材料,并优化挡轮轮辐减重孔直径,提高挡轮的疲劳寿命,从而在强度及韧性上均达到最优.设计长期交变应力状态下的工件必须兼顾材料的强度、韧性及其造型优化,这一结论对各类动态承载机械零部件的设计均具有参考价值. 相似文献
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一种改进的S-random随机交织器的设计 总被引:1,自引:0,他引:1
本文对Turbo码中的关键部件——交织器作了分析,阐明了交织器在Turbo码中的重要作用。同时,混沌理论是非线性科学中的研究热点,对现代科学产生了广泛而深远的影响。本文基于Henon混沌模型和S-random交织器的设计思想提出了一种改进的交织器设计方法,并将其应用于Turbo码中。通过Turbo码的距离谱和联合界对比,本文设计的S-henon交织器在改善Turbo性能上优于S-random交织器。 相似文献
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检测禽流感病毒RT-PCR一步法的建立及H5、H9亚型的鉴定 总被引:5,自引:0,他引:5
目的建立禽流感病毒(AIV)通用型RT-PCR一步法,并鉴定AIV H5和H9亚型。方法根据流感病毒高度保守的M1基因序列,设计一套通用型引物,建立AIVRT-PCR一步法。根据H5、H9亚型HA基因序列,分别设计一套特异性引物,其上、下游引物分别位于裂解位点两侧,应用RT-PCR一步法检测AIV H5和H9亚型,并验证所建立方法的敏感性;通过检测NDV、IBV和IBDV等RNA病毒及计算机软件模拟检测,验证其特异性。结果所建立AIV系列RT-PCR检测方法具有特异、敏感、简便和快速的特点。结论该方法可用于AIV的检测,H5、H9亚型的鉴定及致病性分析。 相似文献
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Resolution of Unknown Heat Source Inverse Heat Conduction Problems Using Particle Swarm Optimization
The main objective of this article is to solve inverse heat conduction problems with the particle swarm optimization method. An enhanced particle swarm optimization (EPSO) algorithm is proposed to overcome the shortcoming of earlier convergence of standard PSO algorithms. The EPSO is used to estimate the unknown time-dependent heat source in complex regions. Numerical experiments indicate the validity and stability of the EPSO method. 相似文献