Robust sliding mode design for uncertain stochastic systems based on H∞ control method

The official published version can be found at the link below.In this paper, the design problem of sliding mode control (SMC) is addressed for uncertain stochastic systems modeled by Itô differential equations. There exist the parameter uncertainties in both the state and input matrices, as well as the unmatched external disturbance. The key feature of this work is the integration of SMC method with H∞ technique such that the robust stochastic stability with a prescribed disturbance attenuation level can be achieved. A sufficient condition for the existence of the desired sliding mode controller is obtained via linear matrix inequalities. The reachability of the specified sliding surface is proven. Finally, a numerical simulation example is presented to illustrate the proposed method.This work was funded by The Royal Society of the U.K.;NNSF of China. Grant Numbers: 60674015, 60674089;The Technology Innovation Key Foundation of Shanghai Municipal Education Commission. Grant Number: 09ZZ60;Shanghai Leading Academic Discipline Project. Grant Number: B50

Two-Dimensional Inversion Asymmetric Topological Insulators in Functionalized III-Bi Bilayers

The search for inversion asymmetric topological insulators (IATIs) persists as an effect for realizing new topological phenomena. However, so for only a few IATIs have been discovered and there is no IATI exhibiting a large band gap exceeding 0.6 eV. Using first-principles calculations, we predict a series of new IATIs in saturated Group III-Bi bilayers. We show that all these IATIs preserve extraordinary large bulk band gaps which are well above room-temperature, allowing for viable applications in room-temperature spintronic devices. More importantly, most of these systems display large bulk band gaps that far exceed 0.6 eV and, part of them even are up to ~1 eV, which are larger than any IATIs ever reported. The nontrivial topological situation in these systems is confirmed by the identified band inversion of the band structures and an explicit demonstration of the topological edge states. Interestingly, the nontrivial band order characteristics are intrinsic to most of these materials and are not subject to spin-orbit coupling. Owning to their asymmetric structures, remarkable Rashba spin splitting is produced in both the valence and conduction bands of these systems. These predictions strongly revive these new systems as excellent candidates for IATI-based novel applications.Comment: 17 pages,5figure

Numerical Simulation of Solid-liquid Flow in Hydrocyclone

Hydrocyclone is widely used as the centrifugal separation equipment to separate, classify and concentrate the product. In this paper, the multiphase flow models of mixture and Euler-Euler are used to simulate the internal three-dimensional flow field of hydrocyclone. It is found that compared to the experiment, the mixture model is shown to have the best performance among the models of mixture, Euler-Euler and discrete phase for the separation simulation when the diameter of solid particle is less than 30 μm. Otherwise, the discrete phase model holds the best performance. Furthermore, the field of static pressure, axial and tangential velocity, and volume fraction in the hydrocyclone is obtained by the mixture model. The outcome is very helpful to explain the separation procedure and optimize the hydrocyclone design

Influence of metal elements on the evolution of CO and CH4 during the pyrolysis of sawdust

Metal elements in biomass ash have been considered to affect the decomposition of large molecule during the pyrolysis of biomass. In this paper, effect of metal elements on the evolution of carbon monoxide (CO) and methane (CH4) was investigated during the pyrolysis of sawdust in a fixed bed reactor and species were detected by Fourier Transform Infrared analyzer. Results showed that all the metal additions restrained the yields of CO and CH4 and the quantity order of production was Fe2O3<ZnO<NaCl<CaO<KCl< Al2O3<No-addition. The addition of Al2O3, Fe2O3 and ZnO shortened the completion time of CO and CH4. Statistical analysis demonstrated that all the metal additions lowered the reaction rate of biomass pyrolysis dynamically