Zhejiang Gongshang University

About: Zhejiang Gongshang University is a education organization based out in Hangzhou, China. It is known for research contribution in the topics: Computer science & Chemistry. The organization has 8258 authors who have published 7670 publications receiving 90296 citations. The organization is also known as: Zhèjiāng Gōngshāng Dàxué.

Simultaneous Reduction of Petri Nets and Linear Constraints for Efficient Supervisor Synthesis

Abstract: Due to state-space explosion and uncontrollable events in discrete-event systems, it is very difficult to design supervisors to enforce user-defined linear-constraints and ensure the liveness of their Petri-net (PN) models with complex structures. Different from all the existing methods, which are to transform original constraints into admissible or weakly admissible ones, the method proposed in this work aims to reduce linear-constraints and PN models simultaneously. As a result, an original PN control problem is equivalently reduced to a simpler one, i.e., the optimal supervisors for them make the same restriction on the behavior of a discrete-event system. Moreover, it can be guaranteed that the original PN system is live if and only if the reduced one is so. Since the state space of a PN may grow exponentially with its size, and the sizes of real discrete-event systems are often too large to handle, the proposed method is useful to greatly reduce the computational complexity of both property-analysis and supervisor-synthesis of discrete-event systems.

Overlooked Role of Peroxides as Free Radical Precursors in Advanced Oxidation Processes

Abstract: Research efforts on advanced oxidation processes (AOPs) have long been focused on the fundamental chemistry of activation processes and free radical reactions. Little attention has been paid to the chemistry of the precursor oxidants. Herein, we found that the precursor oxidants could lead to quite different outcomes. A counterintuitive result was observed in the photoreduction of bromate/iodate: the combination of H2O2 and UV enhanced the reduction of bromate/iodate, whereas the addition of persulfate to the UV system led to an inhibitory effect. Thermodynamic and kinetic evidence suggests that the reduction of bromate in UV/H2O2 was attributable to the direct reaction between HOBr and H2O2. Both experimental determination and kinetic simulation demonstrate that the reaction between HOBr and H2O2 dominated over the •OH-mediated reactions. These results suggest that H2O2 possesses some particular redox properties that distinguish it from other peroxides. The prototypical UV/H2O2 process is not always an AOP: it can also be an enhanced reduction process for chemicals with intermediates that are reducible by H2O2. Considering the increasing interest in persulfate-based AOPs, the results of this study identify some novel advantages of the classical H2O2-based AOPs.