Severe flood events in China are a common cause of life losses. Many efforts have been carried out by the Yellow River Conservancy Commission (YRCC) to understand flood development and impact on the Yellow River. Modeling approaches based on discretization of the modeled domain in square and rectangular grids have great importance in the management of rivers, but they usually present two drawbacks: the required accuracy of the meandering of wide long rivers is not well represented, and the need to use many grid cells reduces computational speed. Modeling and simulation of extreme flood events using unstructured grids has not yet been applied to the Yellow River. This study shows how such a method can be beneficial to decision makers in the Yellow River region in case of flood events. The research shows that a flexible mesh discretization of the domain can overcome the two drawbacks. Along with a test of the proposed modeling method, new characteristics of the spatial evolution of flood events in the Yellow River emerged and are presented, showing the capabilities of DFloridaOW-FM software in modeling such a complex system.@en

This brief investigates the robust model predictive control (MPC) for train regulation in underground railway transportation. By considering the uncertain passenger arrival flow, a constrained state-space model for the train traffic of a metro loop line is developed. The goal of this brief is to design a state feedback control law at each decision step to optimize a metro system cost function subject to safety constraints on the control input. Based on Lyapunov function theory, the problem of optimizing an upper bound on the system cost function subject to input constraints is reduced to a convex optimization problem involving linear matrix inequalities. Moreover, for the inevitable disturbances leading to the delays, the robust MPC strategy of train regulation is designed for a metro loop line such that it ensures the minimization of an upper bound on metro system cost function, and meanwhile guarantees a disturbance attenuation level with respect to the disturbances. Numerical examples are given to illustrate the effectiveness of the proposed methods.@en

A method for highly controllable etching of AlGaN/GaN for the fabrication of high sensitivity HEMT based sensors is developed. The process consists of cyclic oxidation of nitride with O₂ plasma using ICP-RIE etcher followed by wet etching of the oxidized layer. Previously reported cyclic oxidation-based GaN etching obtained very slow etching rate (∼0.38nm/cycle), limited by oxidation depth. The proposed approach allows fine control of the oxidation enabling the formation of accurately controlled recess of very thin (20∼30nm) barrier layers. With optimized power settings, etch rates from ∼0.6 to ∼11nm/cycle were obtained. AFM results did not show any increase in surface roughness after etching, indicating that surface quality of the etched layer was not affected by the etching process.

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http://onlinelibrary.wiley.com/doi/10.15252/embj.201590931/abstract@en