A novel N-N bond cleavage reaction of 4-amino-1,2,4-triazole derivatives

5-Substituted-4-amino-3-thiol-1, 2, 4-triazoles (1a- b) react with orthonitrochloro- benzene or para-nitrochlorobenzene to give N-N bond cleavage products 2a-d, one structure of which (2b) has been unambiguously confirmed by an X-ray structural analysis.     

Synthesis of UV‐curable liquid crystalline diacrylates for the application of polarized electroluminescence

Two series of UV‐curable rod‐like diacrylates containing bis‐tolane (M1–M5) and bis‐stilbene (M6–M10) mesogens were synthesized. All of the diacrylates were prepared through convergent syntheses involving palladium‐catalysed coupling reactions. The thermal transitions and mesomorphic properties of the diacrylates were characterized by differential scanning calorimetry and optical microscopy. All the bis‐tolane‐based monomers reveal nematic phases, except M5 which shows no mesomorphic behaviour. For the bis‐stilbene based monomers, most show no mesomorphic behavior and only M7 and M9 exhibit a SmA phase.     

Directed percolation and the extinction transition on a diffusive substrate

The extinction transition on a 1D heterogeneous substrate with diffusive correlations is studied. Diffusively correlated heterogeneity is shown to affect the location of the transition point, as the reactants adapt to the fluctuating environment. At the transition point the density decays like t^−0.159, as in directed percolation. However, the scaling function describing the behavior away from the transition and other critical exponents shows significant deviations from the known DP behavior. It is suggested, thus, that the off-transition behavior of the system is governed by local adaptation to favored regions.     

Electron scattering states for low-energy spectroscopies

In contrast to bound-state calculations for the valence band regime, the continuous states of half-space systems have not attained a level where a broad variety of methods ensures large applicability and sufficient accuracy for the needs of highly resolved spectroscopy. The multiple-scattering procedure works well in the high-energy range, but lacks either accuracy or convenience when applied to lower energies, where the anisotropic parts of the potential are strongly effective. The concept of Bloch-wave procedures in its original form is less well adapted to scattering boundary conditions, but requires additional theoretical adjustment, such as matching conditions, which often leads to an ill-posed boundary problem of the elliptic equation. The solution then suffers from instabilities preventing the development of stand-alone algorithms. The current state of the subject together with some promising solutions will be presented. Consideration will be given to the multiple scattering approach with anisotropic potentials and to the Bloch-wave development relying on pseudopotential, as well as on singular-potential formulations. The importance and quality of procedures is estimated through a comparison with very low energy electron diffraction (VLEED), low-energy electron diffraction (LEED) and total current spectroscopy (TCS) experiments.     

Charge density measurement and bonding character in LiNiO2

Accurate low-order structure factors of LiNiO₂ were measured by quantitative convergent-beam electron diffraction (QCBED), and then transformed into X-ray structure factors with Mott formula. Combining the structure factors measured by electron diffraction with the structure factors from X-ray diffraction measurements, accurate charge density maps based on a multipole model were obtained. The parameters of the bond critical points (BCP) were calculated for topological analyses. It shows that closed-shell interactions exist between Ni and O atoms, and that the Ni-O and Ni-Ni bonds exhibit some covalent character. The calculated d-orbital occupancies show the charge deficiency at e_g(e_g) orbital and charge surplus at e_g(t_2g) orbital. The remaining 29.12% population of e_g(e_g) is also an indication of covalent component in the Ni-O bond. The unusual small κ_defv value of the O atom is also discussed.     

Coupled Li/Nb and O/F ordering on the Na and Cl sites of the average NaCl structure of Li4NbO4F

The average, as well as the cation and anion ‘disordered’, crystal structure of Li₄NbO₄F has been carefully investigated via coupled neutron and X-ray powder diffraction studies as well as via electron diffraction studies. The existence of a spectacular highly structured diffuse intensity distribution in the latter provides strong evidence for coupled Li¹⁺/Nb⁵⁺ and O²⁻/F⁻ ordering on the Na and Cl sites of the average NaCl structure of Li₄NbO₄F. Bond valence sum calculations have been used to investigate local crystal chemistry as well as to suggest plausible local crystal chemical constraints while ab initio DFT based theoretical calculations of a 2×2×2 supercell have been carried out in order to provide additional insight into the local crystal chemistry of this compound.     

MONTE CARLO STUDY ON THE CRITICAL ADSORPTION POINT OF BONDFLUCTUATED POLYMER CHAINS TETHERED ON ADSORBING SURFACES

The behavior of three-dimensional bond fluctuation model chains tethered on an adsorbing flat surface was simulated by the Monte Carlo method.The dependence of the number of surface contacts M on the interaction strengthεand the chain length N was investigated by a finite-size scaling law M = Nφ[a0 + a1N1/V/κ+ O((N1/vκ)2)] forεnear the critical exponentsφ= 0.49 and 1/v= 0.57.     

Spatial evolutionary game with bond dilution

In this paper, we study numerically the prisoner’s dilemma game (PDG) and snowdrift game (SG) on a two-dimensional square lattice with both quenched and annealed bond dilution. For quenched bond dilution, the system undergoes a dynamical transition at the critical occupation probability q^∗, which is higher than the bond percolation transition point for a square lattice. In the critical region, the defined order parameter has a scaling form as P_e∼(q−q^∗)^β for q<q^∗ with the critical exponents β=1.42 for PDG and β=1.52 for SG, which differ from those with quenched site dilution. For annealed bond dilution, the system exhibits a distinct cooperative behavior. We find that the cooperation is much enhanced in the range of small payoff parameters on a lattice with slightly annealed bond dilution.