Batch grinding kinetics in the presence of two active zones

It is shown that the presence of two active zones in a grinding mill leads to apparent non-first-order breakage of the top feed size in batch grinding. The equations to describe the kinetics of the breakage of the top size and of the total size distribution are obtained, and an analytical solution is given. Parametric analysis shows the influences of the relative magnitudes of the two active zones, the rates of breakage and the rate of mass transfer between the two active zones on the mill product. The concepts may be applicable to any type of mill where two active zones can exist.     

批量生产作业车间的双资源多目标调度问题研究

对于批量生产调度问题,根据批次判定公式确定每种工件能划分的批数及每批的工件数,然后把每个子批当作一个新的工件进行调度。采用遗传算法和禁忌搜索算法相结合的混合优化调度算法,用于解决同时考虑设备和工人的双资源问题,以及综合考虑生产周期、工件总延误时间、设备闲置时间和工人闲置时间的多目标综合优化问题。其中采用多目标决策理论用于确定遗传算法中的目标函数,以及由非劣解集合获得较优解。调度算例表明本研究能获得很好的调度效果。     

起重机信息化产品设计模式研究

针对起重机设计的设计重用和知识继承问题,提出了对机械行业信息化支撑下的"设计模式"研究思路;通过对设计模式的认识比较,以及设计方法与设计模式的异同剖析,形成了以"求用"为目的的起重机设计模式研究取向;通过模式状态模型和起重机信息化产品平台模型,探寻了设计模式的存在方式和表达方式,尝试性地提出了模块化模式、批量参数化模式、系列化模式、计算表模式、库模式等,并给出了表达案例。起重机信息化设计模式的研究对于提高信息化效能以及拓展机械设计模式研究具有一定参考价值。     

铝冷轧乳化液的特性

探讨了铝冷轧乳化液在润滑性、退火清净性和热分离性等方面的特殊性能要求，提出了该乳化液配方研究应遵循的原则。     

Blends of amorphous and crystalline polylactides with poly(methyl methacrylate) and poly(methyl acrylate): a miscibility study

Blends of amorphous and crystalline polylactides (PDLA and PLLA) with poly(methyl methacrylate) (PMMA) and poly(methyl acrylate) (PMA) have been prepared. Thermal behaviour and miscibility of these blends along the entire composition interval were studied by differential scanning calorimetry (d.s.c.). The results were compared with those obtained by dynamic mechanical analysis (DMTA). Only one T_g was found in PDLA/PMA and PDLA/PMMA blends, indicating a high degree of miscibility in both systems. Nevertheless, the PDLA/PMMA blend presented enlargements of the T_g width at high PMMA contents. In this case, additional evidence of complete miscibility was obtained by studying the evolution of the enthalpic recovery peaks which appear after different thermal annealing treatments. When the polylactide used was semicrystalline (PLLA), once the thermal history of the blends had been destroyed, crystallization of PLLA was disturbed in both blends PLLA/PMMA and PLLA/PMA, but in a rather different fashion: in the first case crystallization was almost prevented while in the second one it was favoured. This behaviour was explained in terms of the effect of the higher stiffness as indicated by the value of T_g for PMMA compared to that for PMA.     

温度循环试验中大瓷套开裂的解决方法

主要讨论了大瓷套冷炸、温度循环试验中炸裂及瓷套经磨削入库后开裂的原因。提出了在配方中Ｋ２Ｏ和Ｎａ２Ｏ含量不稳定的情况下,微调配方中长石的含量,确保配方中Ｋ２Ｏ和Ｎａ２Ｏ含量的稳定,从而稳定坯体的烧成温度,解决了瓷套在温度循环中开裂的问题。     

多工艺路线的批量生产调度优化

以优化生产周期为目标,研究了多工艺路线的批量调度问题,提出了一种基于工序优先级的调度算法,并将该算法嵌入到遗传算法中,得到了全局优化的批量调度算法。遗传算法搜索最佳染色体,调度算法把染色体解码为调度。在调度算法中,采用了3种提高生产率的策略,即区分批量启动时间与工序加工时间,在工件到达机床之前做好准备工作;把一批工件分成多个小生产批次,每批次独立加工:一批工件加工部分后就运向后续加工机床,缩小后续机床的等待时间。仿真表明,该调度方法能取得较好结果。     

钢管光亮退火炉炉温-燃烧控制系统的改进

介绍宝钢钢管分公司精整1号光亮退火炉控制系统的改造，采用双交叉比例限幅燃烧控制来进行六段炉温控制，替代空气先行的炉温-燃烧控制系统。     

Adaptive equality prediction of batch processes based on PLS model

There are usually no on-line product quality measurements in batch and semi-batch processes, which make the process control task very difficult. In this paper, a model for predicting the end-product quality from the available on-line process variables at the early stage of a batch is developed using partial least squares (PLS) method. Furthermore, some available mid-course quality measurements are used to rectify the final prediction results. To deal with the problem that the process may change with time, recursive PLS (RPLS) algorithm is used to update the model based on the new batch data and the old model parameters after each batch. An application to a simulated batch MMA polymerization process demonstrates the effectiveness of the proposed method. __________ Translated from Jorunal of Tsinghua Science and Technology(Natural Science Edition), 2004, 44(10): 1360–1363 (in Chinese)     

“模拟退火”在全局最优化中的应用和改进

电信网优化问题经合理简化可转换为四维整数区域上的全局最优化问题.但该问题的费用函数是极端‘病态’的,采用基本的‘模拟退火’算法效年低,解的稳定性也不够满意.本文针对基本 SA 算法的弱点探讨了几种改进方法,使算法效率和解的稳定性都有所改善.