Nankai University

About: Nankai University is a education organization based out in Tianjin, China. It is known for research contribution in the topics: Catalysis & Adsorption. The organization has 42964 authors who have published 51866 publications receiving 1127896 citations. The organization is also known as: Nánkāi Dàxué.

Topological creation and destruction of edge states in photonic graphene.

Abstract: We experimentally demonstrate a topological transition of classical light in ``photonic graphene'': an array of waveguides arranged in the honeycomb geometry. As the system is uniaxially strained (compressed), the two unique Dirac points (present in the spectrum of conventional graphene) merge and annihilate each other, and a band gap forms. As a result, edge states are created on the zigzag edge and destroyed on the bearded edge. These results are applicable for any 2D honeycomb-type structure, from carbon-based graphene to photonic lattices and crystals.

Exfoliated Graphite Oxide Decorated by PDMAEMA Chains and Polymer Particles

Abstract: Exfoliated graphite oxide (GO) sheets with hydroxyl groups and amine groups on the surface were prepared by modification of graphite. Atom transfer radical polymerization (ATRP) initiator molecules were grafted onto the GO sheets by reactions of 2-bromo-2-methylpropionyl bromide with hydroxyl groups and amine groups. Poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) chains on the surface of GO sheets were synthesized by in-situ ATRP. X-ray photoelectron spectroscopy, thermogravimetric analysis, and transmission electron microscopy (TEM) results all demonstrated that polymer chains were successfully produced. After grafting of PDMAEMA, the dispersity of GO sheets in solvents was improved significantly. Poly(ethylene glycol dimethacrylate-co-methacrylic acid) particles were deposited on GO sheets via hydrogen bonding between MAA units on polymer particles and amine groups of PDMAEMA. TEM and scanning electron microscopy were used to characterize the structure of the nanocomposites.

Core−Shell Li3V2(PO4)3@C Composites as Cathode Materials for Lithium-Ion Batteries

Abstract: Core−shell Li3V2(PO4)3@C nanostructured composites were prepared via a sol−gel route followed by hydrothermal treatment. XRD patterns showed that Li3V2(PO4)3 has a monoclinic structure with space group P21/n. TEM images exhibited that Li3V2(PO4)3 particles are encapsulated with a carbon shell ∼10 nm in thickness. Compared with pure Li3V2(PO4)3, core−shell Li3V2(PO4)3@C composites presented enhanced electrochemical Li ion intercalation performances. Cyclic voltammetry and electrochemical impedance spectroscopy disclosed that carbon shells improved Li ion diffusion and electrical conductance significantly and also retarded formation of solid electrolyte interphase film of Li3V2(PO4)3 cathode materials.