DPP-250型包装机控制系统设计

介绍了DPP-250型包装机工艺流程,设计了以FX1N系列PLC为基础的DPP-250型包装机控制系统,重点论述了控制系统的硬件配置、输入输出点分配和软件设计。     

凹版醇水性复合塑料油墨及其制备工艺

研制了一种凹版醇水性复合塑料油墨,该油墨的组分为：多元丙烯酸酯共聚树脂、聚酮树脂、颜料、分散剂、附着力促进剂以及鳌合剂和乙醇.选用了具有醇溶性的多元丙烯酸酯作用油墨的主体树脂,使油墨具有良好的醇溶性和溶剂释放性,再配合采用特殊合成树脂,用以研磨颜料,提高油墨的展色性、流动性,最后添加附着力促进剂和鳌合剂,提高油墨的附着力、耐热性及后工序的各项要求;采用乙醇和水做溶剂,不使用有毒、有害的溶剂,减少了有害溶剂对大气的污染,印刷中以乙醇和水作稀释溶剂,无有毒、有害溶剂残留和排放,安全、无毒、卫生、环保.     

Computational fluid dynamics (CFD) modeling of spouted bed: Influence of frictional stress, maximum packing limit and coefficient of restitution of particles

Following the previous article [Du, W., Bao, X., Xu, J., Wei, W., 2006. Computational fluid dynamics (CFD) modeling of spouted bed: assessment of drag coefficient correlations. Chemical Engineering Science 61 (5), 1401-1420], this contribution describes the influences of the frictional stress, maximum packing limit and coefficient of restitution of particles on CFD simulation of spouted beds. Using the two-fluid method embedded in the commercial CFD simulation package Fluent 6.1, the spouting hydrodynamics of a cylindrical-conical spouted bed was simulated and verified with the experimental data of He et al. [He, Y.L., Lim, C.J., Grace, J.R., Zhu, J.X., Qin, S.Z., 1994a. Measurements of voidage profiles in spouted beds. Canadian Journal of Chemical Engineering 72 (4), 229-234; He, Y.L., Qin, S.Z., Lim, C.J., Grace, J.R., 1994b. Particle velocity profiles and solid flow patterns in spouted beds. Canadian Journal of Chemical Engineering 72(8), 561-568]. The results showed that, for coarse particles, the frictional stress is important only for the annulus computation and has no obvious effects on the hydrodynamics of the solids flow in the spout region. The specification of the maximum packing limit could significantly affect the properties of the pseudo-fluid phase of the particles by changing the radial distribution function. The strong dependence of the pseudo-fluid properties of the particle phase, such as pressure, bulk viscosity and shear viscosity, on the granular temperature accounts for the influence of the coefficient of restitution of particles on CFD modeling. The solids volume fraction at loose packing state is suitable for spouted bed simulations, and a pretest of the coefficient of restitution of particles must be conducted when no experimental datum is available.     

An Application of Silica‐Based Monolithic Membrane Emulsification Technique for Easy and Efficient Preparation of Uniformly Sized Polymer Particles

Summary: Uniformly sized polymer particles were prepared by an emulsification and polymerization technique utilizing a silica monolithic membrane, namely the “silica monolithic membrane emulsification technique”. In this paper, we utilized silica monolithic membrane as a device for the preparation of uniformly sized polymer particles. A mixture of monomers, diluents and oil‐soluble initiator was emulsified into a continuous medium through the silica monolithic membrane and polymerized. The particles obtained had a higher size uniformity than that of particles prepared by previously reported membrane emulsification techniques, such as the Shirasu Porous Glass (SPG) emulsification technique. Through the silica monolithic membrane emulsification technique, we could prepare particles having availability as a possible packing material for solid‐phase extraction (SPE) and high performance liquid chromatography (HPLC).

SEM photograph of silica particles prepared through capillary plate membrane.     

正则稀疏化的多因子量化选股策略

针对高维度数据集特征之间的复杂性,而传统的L1惩罚项不满足Oracle性质的无偏性,将逻辑回归弹性网（LR-Elastic Net）中的L1惩罚项替换为SCAD（Smoothly Clipped Absolute Deviation）和MCP（Minimax Concave Penalty）惩罚项,分别构建了LR-SCAD和LR-MCP模型,在保留稀疏性的同时满足了无偏性,并利用ADMM（Alternating Direction Method of Multipliers）算法进行求解。通过模拟实验发现,LR-Elastic Net模型能很好地处理特征存在相关性的小样本数据,而LR-SCAD和LR-MCP模型在特征存在相关性的大样本数据中表现较好;建立LR-Elastic Net、LR-SCAD和LR-MCP策略,并应用于沪深300指数成分股数据。回测结果显示,LR-SCAD和LR-MCP策略在股票相关性很强的数据中比LR-Elastic Net策略表现更好。     

增材制造技术粉床的数值模拟与分析

选择性激光烧结等增材制造工艺中粉床特性对成型工艺有重要影响。针对颗粒粒径分布类型和层厚等对粉床特性有影响的问题,通过分析增材制造技术中粉床填充过程,提出了一种基于离散元法的增材制造粉床的数值模拟分析方法,分析论述了不同粒径分布和不同层厚对粉床填充性能的影响。结果表明：单一粒径粉床和粒径高斯分布粉床的填充密度和平均配位系数均随着层厚的增大而增大,最后趋于稳定;单一粒径粉床和粒径高斯分布粉床的填充密度和平均配位系数在层厚为80μm和400μm时均大致相等,在其它层厚时,粒径高斯分布粉床的填充密度高于单一粒径粉床的填充密度,且差值随着层厚的增大先增大后减小;单一粒径粉床的平均配位系数高于粒径高斯分布粉床的平均配位系数,且差值随着层厚的增大先增大后减小。这些研究结果可为增材制造粉床颗粒粒径分布类型和层厚选取提供参考依据。     

线性规划模型在股市投资中的应用

通过对线性规划模型和股市投资方法的分析,构建出在其上的基本数学模型,并对2014年第一季度5支股票平均收益率与风险损失率进行分析,构建出存款与证券投资相结合的无风险股市投资多目标线性规划模型,从而给出了在不同参变量取值下的投资组合,对投资者合理投资具有现实意义。     

基于库存论的模型库建立与实现*

以库存论为理论基础,在SQL Server 2000与Visual Studio.NET环境下设计实现了一个模型库;模型库按功能进行了分类介绍,并对每一类中的功能和算法进行阐述,给出了实现的方法。     

连铸圆管坯的质量及其控制(上)

目前我国尚无连铸圆管坯的国家标准或行业标准,各企业只执行自行制订的技术条件。根据试验和理论分析,建议在连铸圆管坯技术条件中增加有关表层细晶区、柱状晶区和等轴晶区厚度比例及芯部状态等内容,并提出了相应的控制方法;鉴于连铸圆管坯质量的重要性,建议尽快制订国家标准。     

美国铝箔工业

美国是一个铝箔大国和强国.2002年铝箔产量596 kt,占全球总产量的24%强,共有铝箔厂22个,总生产能力887 kt;是个铝箔消费大国,2002年的消费量为693 kt,人均消费量2.48 kg;美国是个铝箔净进口国,2002年的净进口量97.023 kt.2002年美国约有辊面宽度不小于1 000 mm的4辊铝箔轧机220台,平均每厂10台.美国生产双零铝箔的企业还不到10家,其他的生产单零箔与厚箔,双零箔的产量约占总产量的20%弱.美国铝业公司在国内有7个铝箔厂,合计生产能力328 kt/a,不但是美国最大的铝箔生产者,也是全球最大的铝箔生产者.2005年美国铝箔的生产能力可达约980 kt/a.