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.

Hydrogen bond induced chiral symmetry breaking in the crystallization of nickel(II) complexes

Abstract: A pair of enantiomers formulated as {Δ-cis-[Ni(en)2OAc][ClO4]} n (Δ-1) and {Λ-cis-[Ni(en)2OAc][ClO4]} n (Λ-1) (en = diaminoethane, OAc− = acetate anion) were obtained when nickel acetate was reacted with diaminoethane and sodium perchlorate in the absence of any chiral source, whereas the reactions of nickel acetate with 1,3-propanediamine and sodium perchlorate only gave a centrosymmetric complex [Ni(1,3-pn)2OAc][ClO4] (2) (1,3-pn = 1,3-propanediamine). Single-crystal X-ray diffraction analyses of all three complexes indicated that the central Ni(II) atoms all have a distorted octahedral coordination geometry, being coordinated by four nitrogen atoms of the diamine ligands, plus two oxygen atoms of OAc−. In complexes Δ-1 and Λ-1, the monomers of {Δ-cis-[Ni(en)2OAc]}+ and {Λ-cis-[Ni(en)2OAc]}+ are connected through intermolecular hydrogen bonds to generate one-dimensional right- and left-handed homochiral helical chains, respectively, while the monomers of [Ni(1,3-pn)2OAc]+ are linked by similar intermolecular hydrogen bonds to form one-dimensional zigzag chains instead of helical chains. The chiral natures of complexes Δ-1 and Λ-1 have been confirmed by circular dichroism spectroscopy.

Néel-type antiferromagnetic skyrmionic crystals on two-dimensional square lattices investigated with optimized quantum Monte Carlo method

Abstract: The formations of individual antiferromagnetic (AF) skyrmions and AF skyrmionic lattices on two-dimensional (2D) magnets with square crystal structure are debatable in recent years, for only an isolated skyrmion can be generated in such systems if classical Monte Carlo (CMC) method is employed. For the sake, we apply here an optimized quantum Monte Carlo approach to a 2D square magnet where the AF Heisenberg exchange (HE) and Dzyaloshinskii–Moriya (DM) interactions co-exist. Consequently, the computing program converges to the equilibrium states with appreciable computational speed, and the results obtained in the last one iteration are able to accurately produce well symmetric and periodic AF skyrmionic lattices (SLs) at elevated temperatures when a considerably strong external magnetic field is exerted perpendicular to the 2D monolayer. Moreover, each of these AF SLs can be decomposed into two almost identical ferromagnetic (FM) SLs, and the distribution of topological charge density also forms symmetric lattice with the same periodicity as the AF SL, dividing the AF SL into several areas of distinct spin configurations. The reasons why the OQMC approach can work beyond CMC method are explained in the Discussion Section.

Syntheses and crystal structures of [Fe(m-NO2phtpy)2](ClO4)2 and [Fe(m-Clphtpy)2](ClO4)2 (m-NO2phtpy = 4′-(3-nitrophenyl)-2,2′:6′,2″-terpyridine and m-Clphtpy = 4′-(3-chlorophenyl)-2,2′:6′,2″-terpyridine)

Abstract: Two iron compounds [Fe(m-NO2phtpy)2](ClO4)21 and [Fe(m-Clphtpy)2](ClO4)22 are synthesized and their structures are determined by single crystal X-ray diffraction. Crystal data for 1 are: orthorhombic, space group Pcca, a = 25.471(4) A, b = 10.8182(18) A, c = 14.682(2) A, Z = 4. Crystal data for 2 are: orthorhombic, space group Pnna, a = 14.521(2) A, b = 23.980(4) A, c = 23.142(4) A, and Z = 8. The iron atoms are coordinated by six N atoms from two terpyridines in both compounds. These two compounds are all linked by hydrogen bonds with C as donor and O as acceptor into a 3D network for 1 and a 2D network for 2. If viewed along the c direction in 1 and the a direction in 2, both compounds show the ordered figure with terpyridine overlapped as a square and the phenyl rings overlapped as a rectangle or a square.

A Prediction of Vehicle Possession in Hunan Province Based on Principal Component and BP Neural Network

Abstract: Prediction of car ownership has direct reference significance for the development of urban transportation and construction of urban roads. By analyzing the impact factors of urban auto possession, this paper first analyzes 8 indicators such as urban population, GDP, road passenger traffic and so on determined by some references, then establish BP neural network model to predict the vehicles possession in Hunan Province from 2006 to 2008. The figures of prediction is 989,300, 1,221,800 and 1,370,300 respectively in 2006, 2007 and 2008, which is very close to the real ownership of 946,400,1,217,200 and 1,426,700 respectively. It shows the prediction is very accurate. This suggests that the BP neural network has very strong learning and generalization ability and can be employed in prediction of vehicle possession effectively. The prediction of car ownership, as a foundational work for transportation planning,has direct reference significance on the development of urban traffic,its control and management and construction of urban road, etc.Early in 1940s this research has been started in foreign countries[1]. Many different models of prediction of car ownership have been developed.Many of them are developed mainly based on the factors such as urban economy, population network capacity, the land utilization and parking facilities.In China there are also some researches on this issue. They predicate the car ownership mainly by time series prediction, regression analysis and fractal theory and entropy method [2~6].However, these methods do not comprehensively describe the complex relationship between car ownership and other factors. The author of this paper chooses some car ownership-related factors and employ principal component method to analyze to obtain the main factors, then tries to find the relationship between BP neural networks and car ownership according to these factors so as to predict the car ownership in Hunan Province form 2006 to 2008, which will be greatly significant to the development of urban transportation, management and construction.

Tho Optimize Model on Management of Transmit Electricity Block in the Electric Power Market

Abstract: By the multiple linear regression,a electric power current of the main circuitry and the linear relation of the contribute of each electrical machine are obtained.And a salience test of the above linear relation is realized.Moreover,a calculational rule,which is simple and reasonable,is designed.And this rule gives attention to the profit of manufacturer and the transmit electricity side.