Optimization of axial symmetrical FGM under thetransient-state temperate field

A numerical procedure for analyzing the temperature distribution in a hollow axisymmetric cylinder,made of functionally gradient material (FGM),was investigated.Based on the thermal elasticity theory and the arbitrary difference precise integration (ADPI) method,temperature distribution through the FGM cylinder in the ring section under a transient-state temperature field was developed and presented.A genetic algorithm (GA) was applied to the thermal stress optimal design of an FGM hollow cylinder,and as a result,the minimum thermal stress distribution in the FGM cylinder was obtained.A corresponding numerical procedure regarding to a ceramic-metal FGM cylinder was performed,and the computational results were discussed.     

Effects of submicron diamonds on the growth of copper in Cu-diamond co-deposition

Submicron diamonds were co-deposited on aluminum substrates with copper from the acid copper sulfate electrolyte by electrolyte-suspension co-deposition.After submicron diamonds were added to the electrolyte,the shape of copper grains transformed from oval or round to polyhedron,the growth mode of copper grains transformed from columnar growth to gradual change in size,and the preferred orientation of copper grains transformed from (220) to (200).Analyzing the variation of cathodic overpotential,it was found that the cathodic overpotential tended to remain unchanged when copper plane (220) grew in the process of electrodepositing pure copper,while it tended to decrease with time when copper plane (200) grew m the process of co-deposition.It was inferred that copper plane (200) was propitious to the deposition of submicron diamonds.     

Effect of magnesium and nickel coatings on the wetting behavior of alumina toughened zirconia by molten Al-Mg ahoy

The wettability of alumina toughened zirconia (ZTA) by Al-Mg alloy was investigated using the sessile drop technique.The effects of nickel coating,magnesium content,nitrogen atmosphere,and processing temperature on the contact angle between the molten alloy and the substrate were determined.Likewise,the effect of these factors on the wetting properties was studied.The results showed that the nickel coating on the ceramic substrate caused a significant reduction in solid/liquid surface energy and the contact angle decreased obviously.The presence of magnesium in the molten aluminum alloy in nitrogen atmosphere reduced the contact angle effectively.The presence of magnesium in the alloy must be at a minimum amount of 2wt％-3wt％.Moreover,it was suggested that some chemical reactions in the Al-Mg-N system led to the production of Mg3N2 and A1N compositions.These compositions improved the wetting properties of the systems by reducing the surface energy of the molten.It was shown that increasing the temperature is also an effective factor for the enhancement of wetting properties.     

Effect of magnesium and nickel coatings on the wetting behavior of alumina toughened zirconia by molten Al-Mg alloy

The wettability of alumina toughened zirconia (ZTA) by Al-Mg alloy was investigated using the sessile drop technique. The effects of nickel coating, magnesium content, nitrogen atmosphere, and processing temperature on the contact angle between the molten alloy and the substrate were determined. Likewise, the effect of these factors on the wetting properties was studied. The results showed that the nickel coating on the ceramic substrate caused a significant reduction in solid/liquid surface energy and the contact angle decreased obvi-ously. The presence of magnesium in the molten aluminum alloy in nitrogen atmosphere reduced the contact angle effectively. The presence of magnesium in the alloy must be at a minimum amount of 2wt%-3wt%. Moreover, it was suggested that some chemical reactions in the Al-Mg-N system led to the production of Mg3N2 and AlN compositions. These compositions improved the wetting properties of the systems by reducing the surface energy of the molten. It was shown that increasing the temperature is also an effective factor for the enhancement of wetting properties.     

墙体自保温材料研究现状分析

为了贯彻国家节约能源和环境保护的政策,介绍了常见的5种墙体保温体系及其优缺点,即外墙外保温、外墙内保温、内外墙混合保温、夹心保温及自保温体系.并对墙体自保温材料在国内研究现状进行论述,指出墙体自保温体系具有广阔的应用前景.     

资源受限下的连续性消耗应急调度模型

目的 解决资源受限下的物资连续性消耗的应急调度物资和时间的优化问题.方法 在各出救点出救时间不确定条件下,建立了以施救成本和因施救不及时导致的损失费用最小化为目标的应急调度优化模型;考虑了出救点的物资量限制和时间限制等约束条件,采用粒子群算法对模型进行优化求解,对设计算例进行仿真实验.结果 求解出出救点的最优运输量和最优运输时间,实现了在规定应急时间内总成本最小的效果,验证了模型的合理性及算法的有效性.结论 模型适合解决在资源受限下的满足应急总成本最小的物资优化和出救时间优化的调度问题.     

二辊矫直过程导板间距工艺参数分析

针对某钢厂棒材矫直过程中二辊矫直机导板间距没有明确规定并且导板磨损严重的情况,用大型非线性有限元软件建立了棒材二辊矫直过程的三维弹塑性有限元模型。基于此模型研究了不同导板间距下矫直力、导板支撑力、塑性变形程度、矫后残余应力及最大挠度的变化规律,综合分析提出了合理的导板间距取值范围。新的导板间距比之前实际应用的值有所增大,应用后导板更换频率降低。