多目标优化理论在蜂窝夹芯结构设计中的应用

在确定了设计变量及目标函数的基础上,根据结构本身的要求,推导出用于多目标优化的5个约束条件.根据多目标优化理论,采用乘除法对蜂窝夹芯结构进行了评价函数的构造,并用VC语言编制了钢质蜂窝夹芯减振板结构的优化程序,该程序可实现结构尺寸及性能的优化,并计算出各目标函数的最终值.     

高速线材轧机锥套故障分析与改进

高速线材生产线精轧机、预精轧机使用的锥套，在材质、结构、处理工艺及生产操作上存在诸多不当之处，为此进行了多项改进，使锥套故障彻底排除，使用寿命达3～5月，而价格仅为进口件的1／3。     

高钒高速钢碳化钒形态的数值化分析

针对碳化钒的不同形态,设计出定量分析软件,并利用形状因子K,实现了高钒高速钢不同碳化物形态数值化处理,当K介于0.785～1.000之间碳化钒形态为团球状;K≤0.223,碳化钒呈开花状.高钒高速钢当碳含量达到4.2%时,K为0.86和当量直径D为0.78μm,碳化物呈团球状均匀分布.     

Effect of surface modification of metal hydride electrode on performance of MH/Ni batteries

A novel method was applied to the surface modification of the metal hydride(MH)electrode of MH/Ni batteries.Both sides of the electrode were plated with a thin silver film about 0.1μm thick using vacuum evaporation plating technology,and the effect of the electrode on the performance of MH/Ni batteries was examined.It is found that the surface modification can enhance the electrode conductivity and decrease the battery ohimic resistance.After surface modification,the discharge capacity at 5C(7.5A)is increased by 212 mA.h and the discharge voltage is increased by 0.11 V,the resistance of the batteries is also decreased by 32%.The batteries with modified electrode exhibit satisfactory durability.The remaining capacity of the modified batteries is 89%of the initial capacity even after 500 cycles.The inner pressure of the batteries during overcharging is lowered and the charging efficiency of the batteries is improved.     

Metallographic sample prepared by ion beam etching

Ion beam etching technique was used to reveal the metallograhpic microstructure and interface morphology of electroplating chromium coating, in particular, whose substrate surface layer was treated in advance by laser quenching. Chemical etchings were also conducted for comparison. The reveal microstructures were observed and analyzed by scanning electron microscopy. The results show that ion beam etching can reveal well the whole microstructures of composite coating-substrate materials.     

工程机械用800MPa低合金高强度钢焊接接头断裂韧性评价

对调质状态800MPa低合金高强度钢及其焊接接头进行了系列温度的断裂韧性测试,讨论不同焊接方法对焊接接头断裂韧性的影响。发现板材的轧制方向对断裂韧性影响显著,LT方向试件的断裂韧性远超过TL方向试件的断裂韧性。在-60℃以上,母材处于上平台延性断裂范畴。在-80℃,裂纹扩展过程中有延脆断裂模式的转变。焊条电弧焊焊缝的断裂韧性与气体保护焊焊缝的断裂韧性相当。尽管常温下焊缝金属的断裂韧性甚至优于母材,但随着试验温度的降低,焊缝金属的断裂韧性迅速下降。在-20℃已发生断裂模式转变,这在结构服役时要引起重视。本研究为大型工程机械的断裂安全评定奠定了基础。     

Phase transformation behavior in Al-Zn-Cu alloys by hammering

The 5Cu40Zn55Al and 15Cu20Zn65Al alloys were prepared in the AI-Zn-Cu system, There exist the metastable phases ε and θ in the two alloys after homogenization treatment and furnace cooling, respectively. It is shown that the particles are refined from 3 mm to less than 10 μm after hammering the two alloys but there are still metastable phases. This means that the phase constituents of the two alloys have no changes by the deformation, which is different from that by balling. The phase constituents are not changed at room temperature by hammering, which is dependent on the deformation mechanism of hammering.     

串联法氧化铝生产中的合流脱硅

合流脱硅是简化联合法生产流程、降低能耗的有效措施。因此。国内外业界做了大量卓有成效的工作。串联法的工艺特点，更宜于采用合流脱硅。试验结果表明，串联法采用常压合流脱硅流程可以达到所需要的硅量指数。文中还对合流脱硅的硅量指数、合流点、合流脱硅温度、赤泥种子和添加石灰乳等问题进行了讨论。     

卷取机动态补偿力矩的计算及在系统中的实现

详细论述了卷取机动态力矩的数学模型及在控制系统中的实现问题,最后给出了采用CAD计算动态力矩和动态电流、确定相关工艺参数的方法.     

Video summarization via minimum sparse reconstruction

The rapid growth of video data demands both effective and efficient video summarization methods so that users are empowered to quickly browse and comprehend a large amount of video content. In this paper, we formulate the video summarization task with a novel minimum sparse reconstruction (MSR) problem. That is, the original video sequence can be best reconstructed with as few selected keyframes as possible. Different from the recently proposed convex relaxation based sparse dictionary selection method, our proposed method utilizes the true sparse constraint L₀ norm, instead of the relaxed constraint _L2,1$L_{2,1}$ norm, such that keyframes are directly selected as a sparse dictionary that can well reconstruct all the video frames. An on-line version is further developed owing to the real-time efficiency of the proposed MSR principle. In addition, a percentage of reconstruction (POR) criterion is proposed to intuitively guide users in obtaining a summary with an appropriate length. Experimental results on two benchmark datasets with various types of videos demonstrate that the proposed methods outperform the state of the art.