Herding and idiosyncratic choices: Nonlinearity and aging-induced transitions in the noisy voter model

We consider the herding-to-non-herding transition caused by idiosyncratic choices or imperfect imitation in the context of the Kirman Model for financial markets, or equivalently the Noisy Voter Model for opinion formation. In these original models, this is a finite-size transition that disappears for a large number of agents. We show how the introduction of two different mechanisms makes this transition robust and well defined. A first mechanism is nonlinear interactions among agents taking into account the nonlinear effect of local majorities. The second one is aging, so that the longer an agent has been in a given state the more reluctant she becomes to change state.     

Ru(II)-catalyzed α-sulfonamidation of cyclic β-ketoesters with sulfonyl azides

α-Sulfonamidation of β-ketoesters with sulfonyl azide has been developed for the first time using a catalytic amount of Ru(II) complex to produce the 1-oxo-2-(sulfonamido)-2,3-dihydro-1H-indene-2-carboxylate and 1-oxo-2-(sulfonamido)-1,2,3,4-tetrahydronaphthalene-2-carboxylate derivatives in good yields. This method also works well with α-iodotetralones to afford the N-(1,4-dioxo-1,4-dihydronaphthalen-2-yl)sulphonamide derivatives under similar conditions.     

Rogue-wave pair and dark-bright-rogue wave solutions of the coupled Hirota equations

Novel explicit rogue wave solutions of the coupled Hirota equations are obtained by using the Darboux transformation.In contrast to the fundamental Peregrine solitons and dark rogue waves, we present an interesting rogue-wave pair that involves four zero-amplitude holes for the coupled Hirota equations. It is significant that the corresponding expressions of the rogue-wave pair solutions contain polynomials of the fourth order rather than the second order. Moreover, dark-brightrogue wave solutions of the coupled Hirota equations are given, and interactions between Peregrine solitons and dark-bright solitons are analyzed. The results further reveal the dynamical properties of rogue waves for the coupled Hirota equations.     

Direct Synthesis of DI-and Trimethoxybenzyl Thiols from the Corresponding Alcohol

An efficient and reliable procedure for the one-pot synthesis of di-and trimethoxybenzyl thiols from the corresponding benzyl alcohol is described.     

Singular Index Pairs

Using Conley's idea of slow exit points, we construct index pairs for singularity perturbed families of lows. Some applications are also presented.     

First-principles calculations of the structural,elastic and electronic properties of MNxC1−x (M = Ti,Zr, Hf; 0 ≤ x ≤ 1) carbonitrides at ambient and elevated hydrostatic pressure

The structural, electronic, and elastic properties of three mixed transition metal carbonitrides TiN_xC_1−x, ZrN_xC_1−x, and HfN_xC_1−x (0 ≤ x ≤ 1) with the rock-salt structure were calculated at ambient and elevated up to 50 GPa hydrostatic pressures in the framework of the density functional theory methods. The lattice constants, densities, and bulk moduli of the considered compounds were shown to behave as linear functions of the nitrogen concentration x. The obtained linear dependencies of all these parameters allow for getting their estimates at any value of x in the range from 0 to 1. Gradual enhancement of the ionicity of the chemical bonds with gradual replacement of carbon by nitrogen was demonstrated by calculating the bond orders and electron density difference distributions.     

阴离子硫氧化还原与Li1-xNiO2-ySy的结构稳定性:第一性原理研究

Ni-rich layered oxides are the preferred cathode materials for high-energy-density lithium-ion batteries currently used in electric vehicles. In this paper, we present a systematic first-principles evaluation of the deintercalation process in the Li_1-xNiO_2-yS_y. The partial density of states (PDOS) characters of the electrons near the Fermi level, redox behaviors, and thermal stability have been investigated within the GGA+U scheme. The results show that the introduction of sulfur alleviates the lattice distortion during charging, suppresses nickel migration, and enhances the stability of oxygen according to the contribution of sulfur anion redox to the charge compensation for the overcharged Li_1-xNiO_2-yS_y. This study provides a new insight on improving the stability of Ni-rich cathode materials by tuning of the electrochemical behaviors based on sulfur anion redox.     

Dependence of the lone pair of bismuth on coordination environment and pressure: An ab initio study on Cu4Bi5S10 and Bi2S3

DFT calculations have been carried out for Cu₄Bi₅S₁₀ and Bi₂S₃ to provide an analysis of the relation between electronic structure, lone electron pairs and the local geometry. The effect of pressure is considered in Bi₂S₃ and the results are compared to published experimental data. Bi³⁺ in Cu₄Bi₅S₁₀ is found at both symmetrically and asymmetrically coordinated sites, whereas the coordination environments of Bi in Bi₂S₃ are asymmetric at room conditions and get more regular with increasing pressure. The charge density maps of the asymmetric sites show the lone pairs as lobes of non-shared charge. These lobes are related to an effective Bi s-Bi p hybridization resulting from coupling to S p orbitals, supporting the modern view of the origin of the stereochemically active lone pair. No effective Bi s-p hybridization is seen for the symmetric site in Cu₄Bi₅S₁₀, whereas Bi s-p hybridization coexists with a much reduced lone pair in Bi₂S₃ at high pressure.     

Electronic Band Structure of Prussian Blue Analog KCo[Fe(CN) 6 ]

The electronic band structure are calculated for KCo[Fe(CN) 6 ] in two oxidation states, (A) Fe II -C-N-Co III and (B) Fe III -C-N-Co II , by using a full potential linearized augmented plane wave (FLAPW) method. For the case (A), the top of valence bands is derived from the Fe- d k states and the bottom of conduction bands from the Co- d n states with an energy gap of 0.81 eV. For the case (B), the spin-polarized calculation is performed and the stable ferrimagnetic but half-metallic solution is obtained.     

A Bacterial Chitinase Acts as Catalyst for Synthesis of the N‐Linked Oligosaccharide Core Trisaccharide by Employing a Sugar Oxazoline Substrate

A chitinolytic enzyme, chitinase A1 from Bacillus circulans WL‐12, was found to catalyze a glycosyl‐transferring reaction to form the N‐linked oligosaccharide core structure, Man(β1‐4)‐GlcNAc(β1‐4)‐GlcNAc, by employing Man(β1‐4)‐GlcNAc‐oxazoline as glycosyl donor. When the reaction was carried out in the presence of 20 v/v% acetone, the trisaccharide was obtained in 32% yield. It has been shown for the first time that a chitinase behaves like an endo‐β‐N‐acetylglucosaminidase in spite of low structural similarity between them.