Establishment Method of Shape Standard Curve Based on Stepwise Optimization and Its Compensation Models

There are very few researches on the shape standard curve currently,and they merely remain on the level of description of the general concept and production experiences,lacking of the in-depth theoretical analysis,and the concrete principle,method and steps for determining the shape standard curve are not put forward,therefore,they are not applicable in industrial production.This is the weakest spot in the research on the basic shape theory.In this paper,the basic shape standard curve and the transverse distribution curve of the exit thickness are attained with stepwise optimization,which is based on the theoretical calculation method of the shape standard curve of strip mills proposed by authors.By calculating the shape discrimination model and the shape forecast model separately,the simultaneous iterative calculation by the previous method is avoided,and the speed and stability of calculation are improved.The compensation models of the transverse temperature difference of the strip,the shape detection roller deflection and the shape of the strip coil are established,respectively,meantime,the basic shape standard curves are compensated,and the relatively perfect theoretical establishment method of the shape standard curve is formed.The simulation and calculation are done on a 1 220 mm five-stand cold strip tandem mill.The simulation and calculation result shows that the principle,method and steps for determining the shape standard curve are correct and feasible,and the correctness of theoretical analysis and calculation is verified.This paper proposes an idea and a method for the establishment of the shape standard curve in the rolling processes of cold strip mills,which develop the theory and model of the shape standard curve and improve the quality and efficiency of the shape control in the rolling processes of cold strip mills.

Stepwise shape optimization of the surface of a vibrating screen

Screening is a technique that is extensively adopted for the separation of discrete materials according to particle characteristics such as size and shape.Wide application of the discrete element method has sparked much research on the vibrating screen,which is a screening apparatus having a specific vibration mode.The shape of the screen surface is a critical factor affecting the sieving performance of the vibrating screen.In this paper,a stepwise optimization method is employed to optimize the screen surface shape of the vibrating screen in discrete element modeling to obtain a high screening efficiency and large processing capacity simultaneously.Adopting this optimization method,a new curved screen with five decks having various inclination angles is presented.Numerical simulations and prototype experiments are conducted to verify the superior sieving performance of the new curved screen.Experimental results clearly show that the new curved screen greatly outperforms three commonly used screens in terms of sieving performance.The conclusions and methodologies of this work will benefit the design and improvement of vibrating screens.

Synergistic band convergence and defect engineering boost thermoelectric performance of SnTe

As an eco-friendly thermoelectric material,Sn Te has attracted extensive attention.In this study,we use a stepwise strategy to enhance the thermoelectric performance of Sn Te.Firstly,Ag Cl is doped into Sn Te to realize band convergence and enlarge the band gap of Ag Cl-doped Sn Te.Ag Cl-doping also induces dense point defects,strengthens the phonon scattering,and reduces the lattice thermal conductivity.Secondly,Sb is alloyed into Ag Cl-doped Sn Te to further optimize the carrier concentration and simultaneously reduce the lattice thermal conductivity,leading to improved thermoelectric dimensionless figure of merit,ZT.Finally,(Sn_(0.81)Sb_(0.19)Te)_(0.93)(Ag Cl)_(0.07)has approached the ZT value as high as~0.87 at 773 K,which is 272%higher than that of pristine Sn Te.This study indicates that stepwise Ag Cl-doping and Sb-alloying can significantly improve thermoelectric performance of Sn Te due to synergistic band engineering,carrier concentration optimization and defect engineering.