University of Science and Technology Beijing

About: University of Science and Technology Beijing is a education organization based out in Beijing, China. It is known for research contribution in the topics: Microstructure & Alloy. The organization has 41558 authors who have published 44473 publications receiving 623229 citations. The organization is also known as: Beijing Steel and Iron Institute.

Reinforcement Learning Control of a Flexible Two-Link Manipulator: An Experimental Investigation

Abstract: This article discusses the control design and experiment validation of a flexible two-link manipulator (FTLM) system represented by ordinary differential equations (ODEs). A reinforcement learning (RL) control strategy is developed that is based on actor–critic structure to enable vibration suppression while retaining trajectory tracking. Subsequently, the closed-loop system with the proposed RL control algorithm is proved to be semi-global uniform ultimate bounded (SGUUB) by Lyapunov’s direct method. In the simulations, the control approach presented has been tested on the discretized ODE dynamic model and the analytical claims have been justified under the existence of uncertainty. Eventually, a series of experiments in a Quanser laboratory platform are investigated to demonstrate the effectiveness of the presented control and its application effect is compared with PD control.

Sb3+ Doping-Induced Triplet Self-Trapped Excitons Emission in Lead-Free Cs2SnCl6 Nanocrystals.

Abstract: Doped halide perovskite nanocrystals (NCs) have opened new opportunities for the emerging optical and optoelectronic applications. Here, we describe a hot-injection synthesis of all-inorganic lead-free Cs2SnCl6 and Sb3+ doped Cs2SnCl6 NCs. Cs2SnCl6 NCs present a blue emission peak at 438 nm, whereas a new broad-band emission peak appears at 615 nm for the Sb3+ doped NCs. Comparative structural and spectral characterizations of Sb3+ doped Cs2SnCl6 NCs with micrometer-sized undoped and Sb3+ doped crystals show that the formation of broad-band orange emission is originted from triplet self-trapped excitons, attributed to the 3Pn-1S0 transitions (n = 0, 1, 2). Our results in Sb3+ doped Cs2SnCl6 materials provide insights into the machanisms of doping-induced emission centers, and it extends the existing knowledge of optical properties of doped halide NCs for further studies.

Grain-Boundary-Induced Drastic Sensing Performance Enhancement of Polycrystalline-Microwire Printed Gas Sensors

Abstract: The development of materials with high efficiency and stable signal output in a bent state is important for flexible electronics. Grain boundaries provide lasting inspiration and a promising avenue for designing advanced functionalities using nanomaterials. Combining bulk defects in polycrystalline materials is shown to result in rich new electronic structures, catalytic activities, and mechanical properties for many applications. However, direct evidence that grain boundaries can create new physicochemical properties in flexible electronics is lacking. Here, a combination of bulk electrosensitive measurements, density functional theory calculations, and atomic force microscopy technology with quantitative nanomechanical mapping is used to show that grain boundaries in polycrystalline wires are more active and mechanically stable than single-crystalline wires for real-time detection of chemical analytes. The existence of a grain boundary improves the electronic and mechanical properties, which activate and stabilize materials, and allow new opportunities to design highly sensitive, flexible chemical sensors.