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.

A New Graphdiyne Nanosheet/Pt Nanoparticle-Based Counter Electrode Material with Enhanced Catalytic Activity for Dye-Sensitized Solar Cells

Abstract: A graphdiyne nanosheet/Pt nanoparticle composite shows outstanding catalytic activity for the reaction of I3−/I− redox pairs, i.e., the best among rGO/Pt nanoparticle composites, Pt nanoparticles and Pt foils. This is ascribed to enhanced electron transfer resulting from the easier chemical interaction between Pt and the triple bond of graphdiyne.

Fluorination vs. chlorination: a case study on high performance organic photovoltaic materials

Abstract: Halogenation is a very efficient chemical modification method to tune the molecular energy levels, absorption spectra and molecular packing of organic semiconductors. Recently, in the field of organic solar cells (OSCs), both fluorine- and chlorine-substituted photovoltaic materials, including donors and acceptors, demonstrated their great potentials in achieving high power conversion efficiencies (PCEs), raising a question that how to make a decision between fluorination and chlorination when designing materials. Herein, we systemically studied the impact of fluorination and chlorination on the properties of resulting donors (PBDB-T-2F and PBDB-T-2Cl) and acceptors (IT-4F and IT-4Cl). The results suggest that all the OSCs based on different donor and acceptor combinations can deliver good PCEs around 13%–14%. Chlorination is more effective than fluorination in downshifting the molecular energy levels and broadening the absorption spectra. The influence of chlorination and fluorination on the crystallinity of the resulting materials is dependent on their introduction positions. As chlorination has the advantage of easy synthesis, it is more attractive in designing low-cost photovoltaic materials and therefore may have more potential in large-scale applications.

MOF-derived CoSe2 microspheres with hollow interiors as high-performance electrocatalysts for the enhanced oxygen evolution reaction

Abstract: Electrocatalytic water splitting has been recognized to be one of the most promising routes to acquire hydrogen. However, the high-efficiency water splitting is limited by the sluggish kinetics of the anodic oxygen evolution reaction (OER). Metal–organic frameworks (MOFs) have been extensively utilized as precursors to synthesize high-performance electrocatalysts. Herein, a facile template-engaged strategy is adopted to fabricate hollow microspheres derived from a Co-MOF. After a thermally induced selenylation process under an argon atmosphere, the Co-MOF is successfully converted into CoSe2 microspheres at different temperatures. The optimized CoSe2-450 microspheres display excellent OER electrocatalytic performance in 1.0 M KOH aqueous solution, exhibiting 10 mA cm−2 at η = 330 mV with a small Tafel slope of 79 mV dec−1, even superior to those of a commercial IrO2 catalyst. Moreover, CoSe2-450 shows excellent durability without obvious decay after 1000 cyclic voltammetry cycles. This is due to the hollow interior of CoSe2 microspheres and well-distributed active sites, which can effectively offer space for fast mass transport and electron transfer.

3D printing of a mechanically durable superhydrophobic porous membrane for oil–water separation

Abstract: Although superhydrophobic porous membranes are considered to be very promising candidates for oil–water separation, their fabrication methods often involve complicated treatments to build a coating with micro/nano-features on a porous mesh (called “coating on a mesh structure”), which can lead to weak mechanical stability of the superhydrophobic surfaces and the formation of inhomogeneous membrane pores. Herein, we report a facile and environmentally friendly 3D printing approach to fabricate superhydrophobic membranes with an ordered porous structure for oil–water separation using hydrophobic nanosilica-filled polydimethylsiloxane (PDMS) ink. The addition of nanosilica can improve the mechanical strength of the ink and thus ensures the formation of desired topographical structures without the risk of collapsing during 3D printing. Through adjusting the geometrical parameters, a superhydrophobic PDMS membrane was obtained, which mainly depended on the roughness at the sub-millimeter scale. More importantly, the 3D printing approach described herein integrated the superhydrophobic surface into the porous framework and resulted in a mechanically durable superhydrophobic membrane, which successfully avoids the weak interface adhesion issue that arises from the traditional “coating on a mesh structure.” Moreover, the pore size of the printed membrane could be easily adjusted via a computer program to optimize both the liquid flux and separation efficiency of the membranes. The maximum oil–water separation efficiency (∼99.6%) could be achieved for the printed porous membrane with the pore size of 0.37 mm, which also exhibited a high flux of ∼23 700 L m−2 h−1.

Fog computing dynamic load balancing mechanism based on graph repartitioning

Abstract: Because of cloud computing's high degree of polymerization calculation mode, it can't give full play to the resources of the edge device such as computing, storage, etc. Fog computing can improve the resource utilization efficiency of the edge device, and solve the problem about service computing of the delay-sensitive applications. This paper researches on the framework of the fog computing, and adopts Cloud Atomization Technology to turn physical nodes in different levels into virtual machine nodes. On this basis, this paper uses the graph partitioning theory to build the fog computing's load balancing algorithm based on dynamic graph partitioning. The simulation results show that the framework of the fog computing after Cloud Atomization can build the system network flexibly, and dynamic load balancing mechanism can effectively configure system resources as well as reducing the consumption of node migration brought by system changes.