药品及个人护理用品(pharmaceutical and personal care products,PPCPs)在污水中广泛检出,低浓度的PPCPs即可对生态环境和人体健康产生不利影响,污水处理厂出水排放是水环境PPCPs的重要源。活性污泥和生物膜工艺是目前最常用的污水生...药品及个人护理用品(pharmaceutical and personal care products,PPCPs)在污水中广泛检出,低浓度的PPCPs即可对生态环境和人体健康产生不利影响,污水处理厂出水排放是水环境PPCPs的重要源。活性污泥和生物膜工艺是目前最常用的污水生物处理工艺,这两种工艺涉及的生化过程复杂,影响因素众多,难以有效去除PPCPs。数学模型是污水处理工艺运行优化的重要工具。本文系统阐述了PPCPs去除模型的建立方法,包括物质和微生物组分及PPCPs去除过程的确定、动力学方程及关键系数的测定与校准、活性污泥和生物膜模型的异同等;综述了污水中PPCPs去除模型的应用研究进展,包括用于评价不同微生物对PPCPs的降解性能、探究污水中PPCPs的生物降解机制及限制因素、优化影响PPCPs去除的参数等,为精准调控污水中PPCPs去除提供参考。展开更多
The bonnet tool polishing is a novel, advanced and ultra-precise polishing process, by which the freeform surface can be polished. However, during the past few years, not only the key technology of calculating the dwe...The bonnet tool polishing is a novel, advanced and ultra-precise polishing process, by which the freeform surface can be polished. However, during the past few years, not only the key technology of calculating the dwell time and controlling the surface form in the bonnet polishing has been little reported so far, but also little attention has been paid to research the material removal function of the convex surface based on the geometry model considering the influence of the curvature radius. Firstly in this paper, for realizing the control of the freeform surface automatically by the bonnet polishing, on the basis of the simplified geometric model of convex surface, the calculation expression of the polishing contact spot on the convex surface considering the influence of the curvature radius is deduced, and the calculation model of the pressure distribution considering the influence of the curvature radius on the convex surface is derived by the coordinate transformation. Then the velocity distribution model is built in the bonnet polishing the convex surface. On the basis of the above research and the semi-experimental modified Preston equation obtained from the combination method of experimental and theoretical derivation, the material removal model of the convex surface considering the influence of the curvature radius in the bonnet polishing is established. Finally, the validity of the model through the simulation method has been validated. This research presents an effective prediction model and the calculation method of material removal for convex surface in bonnet polishing and prepares for the bonnet polishing the free surface numerically and automatically.展开更多
文摘药品及个人护理用品(pharmaceutical and personal care products,PPCPs)在污水中广泛检出,低浓度的PPCPs即可对生态环境和人体健康产生不利影响,污水处理厂出水排放是水环境PPCPs的重要源。活性污泥和生物膜工艺是目前最常用的污水生物处理工艺,这两种工艺涉及的生化过程复杂,影响因素众多,难以有效去除PPCPs。数学模型是污水处理工艺运行优化的重要工具。本文系统阐述了PPCPs去除模型的建立方法,包括物质和微生物组分及PPCPs去除过程的确定、动力学方程及关键系数的测定与校准、活性污泥和生物膜模型的异同等;综述了污水中PPCPs去除模型的应用研究进展,包括用于评价不同微生物对PPCPs的降解性能、探究污水中PPCPs的生物降解机制及限制因素、优化影响PPCPs去除的参数等,为精准调控污水中PPCPs去除提供参考。
基金Supported by Young Teacher Independent Research Subject of Yanshan University of China(Grant No.15LGA002)
文摘The bonnet tool polishing is a novel, advanced and ultra-precise polishing process, by which the freeform surface can be polished. However, during the past few years, not only the key technology of calculating the dwell time and controlling the surface form in the bonnet polishing has been little reported so far, but also little attention has been paid to research the material removal function of the convex surface based on the geometry model considering the influence of the curvature radius. Firstly in this paper, for realizing the control of the freeform surface automatically by the bonnet polishing, on the basis of the simplified geometric model of convex surface, the calculation expression of the polishing contact spot on the convex surface considering the influence of the curvature radius is deduced, and the calculation model of the pressure distribution considering the influence of the curvature radius on the convex surface is derived by the coordinate transformation. Then the velocity distribution model is built in the bonnet polishing the convex surface. On the basis of the above research and the semi-experimental modified Preston equation obtained from the combination method of experimental and theoretical derivation, the material removal model of the convex surface considering the influence of the curvature radius in the bonnet polishing is established. Finally, the validity of the model through the simulation method has been validated. This research presents an effective prediction model and the calculation method of material removal for convex surface in bonnet polishing and prepares for the bonnet polishing the free surface numerically and automatically.
