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.

Sensitive voltammetric determination of tryptophan using an acetylene black paste electrode modified with a Schiff's base derivative of chitosan

Abstract: Chitosan was modified by salicylaldehyde via Schiff's base reaction and the resulting product was modified on the surface of an acetylene black paste electrode (ABPE) by the drop-coating method. In 0.5 mol L(-1) acetate buffer (pH 4.2), a substantial increase in the anodic stripping peak current of tryptophan (Trp) (compared to conventional bare carbon paste electrode (CPE) and bare ABPE) is observed at the Schiff's base chitosan-modified electrode. The parameters influencing voltammetric determination of Trp have been optimized. Under the selected conditions, the linearity between the anodic peak currents and concentrations of Trp demonstrated a wide range of 6.0 × 10(-8) mol L(-1) to 2.0 × 10(-6) mol L(-1), 2.0 × 10(-6) mol L(-1) to 4.0 × 10(-5) mol L(-1) and 4.0 × 10(-5) mol L(-1) to 1.0 × 10(-4) mol L(-1), a low detection limit of 2.0 × 10(-9) mol L(-1) was obtained after a 60 s accumulation. In addition, the developed electrochemical sensor has been successfully applied for the determination of Trp in pharmaceutical and biological samples with satisfactory assay results.

Communication: Oscillated band gaps of B/N-codoped α-graphyne

Abstract: The physical mechanism for the electronic structures tuning and band gap opening of α-graphyne are investigated from the first principles calculations. The pathway of using B and N atoms to codope into graphyne is proposed. After codoping, B atom plays a role of hole doping and N atom acts as electron doping. In codoped graphyne, the Fermi energy returns around the Dirac point and a gap is introduced. Interestingly, the opened gaps oscillate periodically with the increasing distances between B and N atoms with the gap from 0.07 eV to 0.50 eV, which is caused by the breaking sublattice symmetry.

Three-dimensional lanthanide–silver heterometallic coordination polymers: syntheses, structures and properties

Abstract: Assembly reactions of 5-(isonicotinamido)isophthalic acid (H2INAIP) with Ln2O3 or Ln(NO3)3·6H2O together with NaOH in the presence of AgNO3 result in formation of two series of new 4d–4f heterometallic coordination polymers {[LnAg(INAIP)2]·3H2O}n [Ln = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5)] and {[LnAg(INAIP)2(H2O)]·xH2O}n [Ln = La (6), Pr (7), Nd (8), x = 0; Dy (9), Er (10), x = 1]. The results of single-crystal X-ray diffraction analysis indicate that 1–5 are isomorphous and have 2-fold interpenetrated 3D structure with 3-nodal net Point (Schlafli) symbol for net: (4·62)4(44·66·815·103), while 6–10 are isostructural with similar non-interpenetrating 3D frameworks containing 2D lanthanide–carboxylate bilayers. The results indicate that the reaction conditions have great influence on the structure of the resulting complexes in this system. Furthermore, 3 and 5 show intense red and green fluorescent emissions, respectively, and the emission bands of Nd(III) were observed in the near IR region for 1. The magnetic properties of 1–5, 9 and 10 were investigated.

Tripole-mode and quadrupole-mode solitons in (1 + 1)-dimensional nonlinear media with a spatial exponential-decay nonlocality

Abstract: The approximate analytical expressions of tripole-mode and quadrupole-mode solitons in (1 + 1)-dimensional nematic liquid crystals are obtained by applying the variational approach. It is found that the soliton powers for the two types of solitons are not equal with the same parameters, which is much different from their counterparts in the Snyder-Mitchell model (an ideal and typical strongly nolocal nonlinear model). The numerical simulations show that for the strongly nonlocal case, by expanding the response function to the second order, the approximate soliton solutions are in good agreement with the numerical results. Furthermore, by expanding the respond function to the higher orders, the accuracy and the validity range of the approximate soliton solutions increase. If the response function is expanded to the tenth order, the approximate solutions are still valid for the general nonlocal case.

Interaction between anomalous vortex beams in nonlocal media

Abstract: In this paper, the interactional behaviors of anomalous vortex beams in highly nonlocal media are investigated. An analytical expression describing the interaction is given, and some numerical simulations are carried out to illustrate the interactional characteristics. It is found that two interactional anomalous vortex beams always attract each other, and their evolution is periodical. The influence of different relative phases between two anomalous vortex beams on their interaction is presented in details.