Hengyang Normal University

About: Hengyang Normal University is a education organization based out in Hengyang, China. It is known for research contribution in the topics: Graphene & Adsorption. The organization has 1087 authors who have published 1280 publications receiving 13850 citations. The organization is also known as: Hengyang Teachers' College & Héngyáng Shīfàn Xuéyuàn.

Thermodynamic Properties in Triangular-Lattice Superconductors

Abstract: The study of superconductivity arising from doping a Mott insulator has become a central issue in the area of superconductivity. Within the framework of the kinetic-energy-driven superconducting (SC) mechanism, we discuss the thermodynamic properties in the triangular-lattice cobaltate superconductors. It is shown that a sharp peak in the specific heat appears at the SC transition temperature $$T_\mathrm{c}$$ , and then the specific heat varies exponentially as a function of temperature for temperatures $$T

4,6-Dimethyl-pyrimidin-2-amine.

Abstract: The asymmetric unit of the title compound, C6H9N3, contains three crystallographically independent mol­ecules of similar geometry. All of the mol­ecules are almost planar, with r.m.s. deviations of 0.003, 0.016 and 0.005 A. In the crystal, the mol­ecules are linked by N—H⋯N hydrogen bonds into zigzag ribbons parallel to the c axis, generating rings of R22(8) graph-set motif.

A sum rule of uniaxial anisotropy and external magnetic field for formation of Néel-type skyrmion lattices in two-dimensional ferromagnets

Abstract: It is generally believed that the perpendicular magnetic anisotropy (PMA) plays an important role in stabilizing skyrmion lattices (SkL) in two-dimensional (2D) magnetic systems in which both Heisenberg exchange and Dzyaloshinskii-Moriya interactions co-exist, and the skyrmion sizes in SkLs are mainly determined by the strengths of these two intrinsic interactions. To investigate the details, we employ here a quantum computational approach we develop in recent years to simulate the Neel-type skyrmion lattices formed on a 2D PdFe/Ir(1 1 1)-like film. From our simulated results, we find that: within an external magnetic field applied normal to the film plane, the PMA is indeed able to help induce Neel-type SkLs in a wider field range; however, to stabilize the SkLs, the PMA cannot be too strong, the strengths of the external magnetic field and the maximal PMA must satisfy a sum rule since the effective perpendicular magnetic field generated by these two interactions cannot exceed a largest value. We also notice that the periodical boundary condition imposed on the FM system in simulations is able to facilitate SkL formations, and it can also modify the skyrmion size in a certain extend.

Synthesis, structure, thermostability and luminescence properties of Zn(II) and Cd(II) coordination polymers based on dimethysuccinate and flexible 1,4-bis(imidazol-1-ylmethyl)benzene ligands.

Abstract: The design and synthesis of functional coordination polymers is motivated not only by their structural beauty but also by their potential applications. ZnII and CdII coordination polymers are promising candidates for producing photoactive materials because these d10 metal ions not only possess a variety of coordination numbers and geometries, but also exhibit luminescence properties when bound to functional ligands. It is difficult to predict the final structure of such polymers because the assembly process is influenced by many subtle factors. Bis(imidazol-1-yl)-substituted alkane/benzene mol­ecules are good bridging ligands because their flexibility allows them to bend and rotate when they coordinate to metal centres. Two new ZnII and CdII coordination polymers based on mixed ligands, namely, poly[[μ2-1,4-bis­(imidazol-1-ylmeth­yl)benzene-κ2N3:N3′]bis­(μ3-2,2-di­methyl­butano­ato-κ3O1:O4:O4′)dizinc(II)], [Zn2(C6H8O4)2(C14H14N4)]n, and poly[[μ2-1,4-bis­(imidazol-1-ylmeth­yl)benzene-κ2N3:N3′]bis­(μ3-2,2-di­methyl­butano­ato-κ5O1,O1′:O4,O4′:O4)dicadmium(II)], [Cd2(C6H8O4)2(C14H14N4)]n, have been synthesized under hydro­thermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis, IR spec­troscopy and thermogravimetric analysis. Both complexes crystallize in the monoclinic space group C2/c with similar unit-cell parameters and feature two-dimensional structures formed by the inter­connection of S-shaped Zn(Cd)–2,2-di­methyl­succinate chains with 1,4-bis­(imidazol-1-ylmeth­yl)benzene bridges. However, the CdII and ZnII centres have different coordination numbers and the 2,2-di­methyl­succinate ligands display different coordination modes. Both complexes exhibit a blue photoluminescence in the solid state at room tem­perature.