Scheduling a single batch-processing machine with non-identical job sizes in fuzzy environment using an improved ant colony optimization

In this paper, we introduce the fuzzy model of the makespan on a single batch-processing machine with non-identical job sizes. The uncertainty of the jobs and the machine in the processing is denoted using fuzzy logic. Then an improved ant colony optimization (ACO) method is proposed and the Metropolis criterion is used to select the paths of ants to overcome the immature convergence of the algorithm. In the experiment, we adopt the random instances and the results of the fuzzy makespan demonstrate that the proposed algorithm outperforms GA and SA in all instances.     

Facile hydrothermal synthesis of CeO2 nanosheets with high reactive exposure surface

CeO₂ nanosheets with (1 1 0) dominated surface were synthesized for the first time by a facile one-step hydrothermal method without the assistance of any surfactant or template. The role of NH₃·H₂O on tailoring the morphology of CeO₂ nanocrystals was investigated. It was found the NH₃·H₂O not only serves as the precipitant, but also acts as structural direction agent in the formation of (1 1 0)-dominated CeO₂ nanosheets. Raman and XRD spectra showed that the sample has a cubic fluorite structure. Compared with bulk CeO₂ materials, the prepared CeO₂ nanosheets exhibit an obvious blue-shift in UV absorbance. The increase of the direct band gap energy of the obtained sample exceeds 8%. This method provides an environmentally friendly way for preparing CeO₂ nanostructures and tailoring their morphology. It may also be extended to the synthesis of other nanomaterials.     

国产化分子筛干燥器新应用探索

介绍国内设计国产装备分子筛干燥器在大型合成氨装置中的运行状况,探讨持续开发新设想--用于大型尿素装置中超临界二氧化碳气体脱水,可以改善离心式二氧化碳气体压缩机的操作条件,解决压缩机第四段密封件频繁损坏的问题,达到降低维修费用、延长生产时间的目的,具有节能或增产的效果.     

Preparation and characterization of novel nanocomposites based on polyacrylonitrile/kaolinite

A novel intercalation nanocomposite based on polyacrylonitrile (PAN)/kaolinite was prepared by a simple in situ emulsion polymerization in the presence of organically modified layered silicates (kaolinite). The crude kaolinite (K₀) was firstly modified by dimethylsulfoxide-methanol and potassium acetate-aqueous systems; acrylonitrile monomer was then intercalated into kaolinite by displacing potassium acetate from KAc-kaolinite (the kaolinite modified by KAc, marked as K₂). The polymer/kaolinite composites were prepared by in situ emulsion polymerization, and characterized by means of X-ray diffraction, scanning electron microscope, transmission electron microscope and thermal gravimetric analysis. Experimental results indicate that the clay layers of kaolinite in PAN/K₂ composites are well distributed and delaminated. The weight-average molecular weights were measured by small-angle X-ray scattering for all samples. The presence of clay results in an increase in molecular weights compared to pure PAN polymer due to the highly crosslinked structure.     

回溯法与DEclat算法结合的模具组合分配方法

生产预制构件所使用的模具在模台上的组合分配受多种因素影响,会产生多种组合分配结果。为了解决这类问题,快速找到模具在模台上的最佳分配结果,提出一种基于回溯法与改进的Eclat算法结合的模具组合方法。首先基于历史数据中的模具组合关系构建二叉树模型,通过回溯法对二叉树进行搜索,得到所有理论上可行的模具组合结果;再通过使用改进的BL定位算法将这些组合结果在固定面积的模台上进行预放置,从中筛选出符合实际放置条件的模具组合结果;应用Eclat算法从已筛选出的组合结果中获取最优模具适配组合集,进而确定不同型号模具间的关联规则,并将其用于指导新构件生产任务中模具在模台上的分配过程;同时通过引入划分思想和突出基于概率的先验约束思想改进Eclat算法,提升其在处理大规模数据时的运行效率。最后通过采用预制构件生产企业中的实例数据进行仿真测试,验证了该方法对快速解决模具模台组合分配问题的有效性。     

各向异性地基条件下条形基础动力试验研究

地震液化现象一直是土动力学里的一个热门研究课题，前期研究表明由砂土颗粒之间接触的法向分布和颗粒形状所引起的内在各向异性会对砂土动力学特性会有影响。而现有的液化判别方法没有考虑砂土的内在各向异性，使得地震对上部结构的影响很难准确的评价，本研究通过专门设计的离心机模型箱控制砂土的不同沉积方向模拟地基的内在各向异性，并且通过6个离心机振动模型试验研究各向异性的砂土地基对条形基础的动力学特性的影响，包括条形基础的加速度、水平位移的影响。与前期的无条形基础的研究结果相似，在饱和情况下，砂土的内在各向异性对条形基础的动力学特性影响非常大，加速度和超孔隙水压力表明，沉积方向为90o的地基使得条形基础的破坏较为严重，引发严重的地表沉降和基础的水平残余位移。为了更加准确的预测结构物在地震区的动力特性，此研究结果显示应在工程勘察对地基的评价进行修正。     

基于多层BP神经网络的扑克牌识别

实现了多层BP神经网络识别扑克牌图像的方法，首先使用C语言来编写BP神经网络的算法以及用VC＋＋来实现对扑克牌图像的分析，然后再使用大量已知花色和牌点的扑克牌输入，作网络训练，训练完成后，利用网络识别样本扑克牌和带噪声的扑克牌。结果表明，该方法能够较准确地识别GIF扑克牌图像。     

Pro/MoldDesign在模具零件设计中的应用

介绍了利用Pro／MoldDesign进行模具设计的基本流程,并以手机外壳零件为例,利用现有的三维零件模型创建参照零件和工件、模型的检验（拔模和厚度检验等）、分形线／面的创建,模具体积块的创建及模拟打开过程,对建模过程中的软件操作进行了简要的分析,实现了Pro／E软件在复杂型面模具设计与制造中的应用。为利用现有实体模型设计生成模具提供了一种切实可行的模具设计方案。     

高强混凝土L形柱框架节点的非线性有限元分析

在华东交通大学所做试验的基础上,利用有限元分析软件ANSYS对L形柱框架节点进行了非线性有限元分析,主要考察裂缝发展机理及轴压比对节点受剪承载力的影响。经过分析,得到了高强混凝土L形柱框架节点受剪承载力在不同轴压比情况下的变化规律。     

Precipitation of Al3Zr Dispersoids under Various Homogenization and Its Effect on Recrystallization in 2198 Al–Cu–Li Alloy

Herein, the precipitation of Al₃Zr during one- and two-step homogenization processes is studied by the transmission electron microscopy method, and its effect on recrystallization is investigated by the electron backscattering diffraction technique after the same hot compression and solution treatment, respectively. The results show that when the temperature reaches 430 °C, just some small Al₃Zr dispersoids are visible in samples that undergo one-step treatment. As the first-step homogenization temperature increases from 365 to 430 °C, Al₃Zr radius increases from 9.4 to 19.1 nm while the number density decreases rapidly from 1201 to 183 μm⁻³. In addition, the average radius of Al₃Zr increases to 22.1 nm while the number density decreases to 76 μm⁻³ when the sample is homogenized at 500 °C/24 h. After a double-step homogenization with decreased first-step temperature, lower recrystallization fraction is obtained. Therefore, the optimal homogenization treatment is determined to be 365 °C/16 h + 500 °C/24 h, after which the most desirable Al₃Zr distribution and the smallest recrystallization fraction are obtained during thermomechanical process. This result can provide a more appropriate parameter for homogenization treatment in order to achieve a more dispersed distribution, which will result in stronger pinning force during the thermomechanical process.