Sc-phthalocyanine sheet: Promising material for hydrogen storage

It has been a long-standing dream to have high surface area materials with isolated and exposed transition-metal ions for hydrogen storage. The flexible synthesis procedure proposed recently by M. Abel, et al. [J. Am. Chem. Soc. 133, 1203 (2011)] and A. Sperl et al. [J. Am. Chem. Soc. 133, 11007 (2011)] provides a different pathway to achieve this goal. Using first-principles theory and grand canonical Monte Carlo simulation, we carry out a systematic study of 3d transition metals (Sc to Zn)-phthalocyanine porous sheets and find that Sc-phthalocyanine can store 4.6 wt. % hydrogen at 298 K and 100 bar

State transition of a non-Ohmic damping system in a corrugated plane

Anomalous transport of a particle subjected to non-Ohmic damping of the power $\delta$ in a tilted periodic potential is investigated via Monte Carlo simulation of generalized Langevin equation. It is found that the system exhibits two relative motion modes: the locking state and the running state. Under the surrounding of sub-Ohmic damping ($0<\delta<1$), the particle should transfer into a running state from a locking state only when local minima of the potential vanish; hence the particle occurs a synchronization oscillation in its mean displacement and mean square displacement (MSD). In particular, the two motion modes are allowed to coexist in the case of super-Ohmic damping ($1<\delta<2$) for moderate driving forces, namely, where exists double centers in the velocity distribution. This induces the particle having faster diffusion, i.e., its MSD reads $= 2D^{(\delta)}_{eff} t^{\delta_{eff}}$. Our result shows that the effective power index $\delta_{\textmd{eff}}$ can be enhanced and is a nonmonotonic function of the temperature and the driving force. The mixture effect of the two motion modes also leads to a breakdown of hysteresis loop of the mobility.Comment: 7 pages,7 figure

Dynamics of delay induced composite multi-scroll attractor and its application in encryption

This work was supported in part by NSFC (60804040, 61172070), Key Program of Nature Science Foundation of Shaanxi Province (2016ZDJC-01), Innovative Research Team of Shaanxi Province(2013KCT-04), Fok Ying Tong Education Foundation Young Teacher Foundation(111065), Chao Bai was supported by Excellent Ph.D. research fund (310-252071603) at XAUT.Peer reviewedPostprin

Poly[[(4,4′-bipyridine-κN)[μ3-(S)-2-hy­droxy­butane­dioato-κ4 O 1,O 2:O 4:O 4′]zinc] dihydrate]

In the title compound, {[Zn(C4H4O5)(C10H8N2)]·2H2O}n, the ZnII ion displays a distorted tetra­gonal–pyramidal coordination environment with one hy­droxy O and three carboxyl­ate O atoms from three malate anions, and the one remaining position occupied by an N atom from a 4,4′-bipyridine ligand. The pyridine rings of the 4,4′-bipyridine ligand are twisted with respect to each other by a dihedral angle of 35.8 (2)°. The uncoordinated water mol­ecules are linked to the complex mol­ecules by O—H⋯O hydrogen bonds. Each malate anion forms four coordination bonds with three Zn atoms, establishing a layer structure parallel to the ac plane. Adjacent layers are further linked via O—H⋯N hydrogen bonding. π–π stacking between the pyridine rings [face-to-face distance = 3.651 (3) Å] occurs in the crystal structure

Bis[tris­(ethyl­enediamine-κ2 N,N′)cobalt(III)] octa­kis-μ-3-oxido-hexa­deca-μ2-oxido-tetra­deca­oxido-μ12-tetra­oxo­silicato-octa­molybdenum(VI)hexa­vanadium(IV,V) hexa­hydrate

The title compound, [Co(C2H8N2)3]2[SiMo8V4O40(VO)2]·6H2O, was prepared under hydro­thermal conditions. The asymmetric unit consists of a transition metal complex [Co(en)3]3+ cation (en is ethyl­enediamine), one half of an [SiMo8V4O40(VO)2]6− heteropolyanion, two solvent water mol­ecules in general positions and two half-mol­ecules of water located on a mirror plane. In the complex cation, the Co3+ ion is in a distorted octa­hedral coordination environment formed by six N atoms of the three chelating en ligands. One of the en ligands exhibits disorder of its aliphatic chain over two sets of sites of equal occupancy. The [SiMo8V4O40(VO)2]6− heteropolyanion is a four-electron reduced bivanadyl-capped α-Keggin-type molybdenum–vanadium–oxide cluster. In the crystal, it is located on a mirror plane, which results in disorder of the central tetra­hedral SiO4 group: the O atoms of this group occupy two sets of sites related by a mirror plane. Furthermore, all of the eight μ2-oxide groups are also disordered over two sets of sites with equal occupancy. There are extensive inter­molecular N—H⋯O hydrogen bonds between the complex cations and inorganic polyoxidoanions, leading to a three-dimensional supra­molecular network

Ambipolar ferromagnetism by electrostatic doping of a manganite

Complex-oxide materials exhibit physical properties that involve the interplay of charge and spin degrees of freedom. However, an ambipolar oxide that is able to exhibit both electron-doped and hole-doped ferromagnetism in the same material has proved elusive. Here we report ambipolar ferromagnetism in LaMnO3, with electron–hole asymmetry of the ferromagnetic order. Starting from an undoped atomically thin LaMnO3 film, we electrostatically dope the material with electrons or holes according to the polarity of a voltage applied across an ionic liquid gate. Magnetotransport characterization reveals that an increase of either electron-doping or hole-doping induced ferromagnetic order in this antiferromagnetic compound, and leads to an insulator-to-metal transition with colossal magnetoresistance showing electron–hole asymmetry. These findings are supported by density functional theory calculations, showing that strengthening of the inter-plane ferromagnetic exchange interaction is the origin of the ambipolar ferromagnetism. The result raises the prospect of exploiting ambipolar magnetic functionality in strongly correlated electron systems

Liquid-liquid equilibrium for extraction of benzene from 1-hexene using two different solvents

Two different solvents had been used to separate benzene from 1-hexene under atmosphere pressure by employing one of the following two solvents, viz.: dimethyl sulfoxide (DMSO) at 298.15 K and 318.15 K, and furfural at 298.15 K. A series of liquid-liquid equilibrium (LLE) data had been obtained and the distribution coefficient together with the separation factor were calculated from them. Both the NRTL and the UNIQUAC models could fit in with the experimental data quite well

On Entire Function Solutions to Fermat Delay-Differential Equations

This paper concerns the existence and precise expression form of entire solutions to a certain type of delay-differential equation. The significance of our results lie in that we generalize and supplement the related results obtained recently