Dalian University of Technology

About: Dalian University of Technology is a education organization based out in Dalian, China. It is known for research contribution in the topics: Catalysis & Finite element method. The organization has 60890 authors who have published 71921 publications receiving 1188356 citations. The organization is also known as: Dàlián Lǐgōng Dàxué.

Surface-Confined Fabrication of Ultrathin Nickel Cobalt-Layered Double Hydroxide Nanosheets for High-Performance Supercapacitors

Abstract: The design and fabrication of 2D nanostructure electrodes with desired electrochemical activities is highly demanded for electrocatalysis and supercapacitors. Herein, the tuned fabrication of ultrathin and tortuous nickel/cobalt-layered double hydroxide (NiCo-LDH) nanosheets via a graphene oxide (GO) surface-confined strategy is reported, yielding nanosheets with a thickness of 1.7–1.8 nm that is duplicated from the graphene oxides in terms of both the lateral size and the shape. It has been found that the C/O functional groups on the GO surface have functioned to promote the oxidation of Co2+ to Co3+, and to transform the β-phase NiCo-hydroxide (NiCo-OH) into the LDH-phase with tuned homogenous composition and geometry. The ultrathin NiCo-LDH nanosheets mimic the morphology and size of the graphene due to the surface-confined and/or surface-guided growth. The as-obtained NiCo-LDH-graphene (NiCo-LDH-G) nanosheets exhibit a superior electrocatalytic activity for oxygen evolution reaction, evidenced by a small overpotential of 0.337 V (@10 mA cm−2 in 0.1 m KOH electrolyte), and a high charge storage capability of 1489 F g−1 as electrodes for supercapacitors. This 2D surface-confined growth strategy may pave a way for the fabrication of ultrathin 2D materials including but not limited to transition metal hydroxides for high-performance electrochemical applications.

QoS-Guarantee Resource Allocation for Multibeam Satellite Industrial Internet of Things With NOMA

Abstract: The traditional ground industrial Internet of Things (IIoT) cannot supply wireless interconnections anywhere due to its small-scale communication coverage. In this article, a multibeam satellite IIoT in Ka-band is proposed to realize wide-area coverage and long-distance transmissions, which uses nonorthogonal multiple access (NOMA) for each beam to improve transmission rate. To guarantee Quality of Service (QoS) for the satellite IIoT, the beam power is optimized to match the theoretical transmission rate with the service rate. The NOMA transmission rate for each beam is maximized by optimizing the power allocation proportion of each node subject to the constraints of the total power for the beam and the minimal transmission rate for each node within the beam. Satellite-ground integrated IIoT is proposed to use the ground cellular network to supplement the satellite coverage in the blocked areas. The power allocation and network selection for the integrated IIoT are proposed to decrease the transmission cost. Simulation results are provided to validate the superiority of employing NOMA in the satellite IIoT and show higher transmission performance for the QoS-guarantee resource allocation.