Modern energy density functional for nuclei and the nuclear matter equation of state

We discuss a method of determining a modern energy density functional (EDF) in nuclei. We adopt a Skyrme type EDF and fit the Skyrme parameters to an extensive set of experimental data on the ground-state binding energies, radii, and the breathing mode energies of a wide range of nuclei. We further constrain the values of the Skyrme parameters by requiring positive values for the slope of the symmetry energy S, the enhancement factor κ, associated with the isovector giant dipole resonance, and the Landau parameter G ₀^′. This is done within the approaches of Hartree-Fock (HF) and HF with the inclusion of correlation effects, using a simulated-annealing based algorithm forminimizing χ ².We also present results of HF based random phase approximation for the excitation strength function of the breathing mode and discuss the current status of the nuclear matter incompressibility coefficient.     

Percolation clusters above criticality form Kardar-Parisi-Zhang surfaces

This study is concerned with the characteristics of regular (isotropic) percolation clusters above the critical threshold p{c}. Analytic arguments for the general dimension case, and numerical results for the two-dimensional case, lead to the conclusion that the characteristics of the shortest paths (defined as the chemical distance l) between given two sites on a percolation cluster are similar to the characteristics of optimal paths in the directed polymer model. A corollary which should be valid for the general dimension case, and verified by numerical results for the two-dimensional case, is that a cluster whose sites are at chemical distance l from a given site forms a Kardar-Parisi-Zhang surface.     

Distributions and moments of structural properties for percolation clusters

We study numerically and by scaling methods the distributions and moments of several structural properties of percolation clusters in two and three dimensions. The clusters are generated at criticality and properties such as the distribution of the mass as a function of linear size or chemical distance are studied. Our results suggest that the hierarchy of moments can be represented by a single gap exponent. Using a scaling approach, we obtain analytical forms for the different distribution functions which agree very well with the numerical data.     

Fourier-Laplace analysis of the multigrid waveform relaxation method for hyperbolic equations

The multigrid waveform relaxation (WR) algorithm has been fairly studied and implemented for parabolic equations. It has been found that the performance of the multigrid WR method for a parabolic equation is practically the same as that of multigrid iteration for the associated steady state elliptic equation. However, the properties of the multigrid WR method for hyperbolic problems are relatively unknown. This paper studies the multigrid acceleration to the WR iteration for hyperbolic problems, with a focus on the convergence comparison between the multigrid WR iteration and the multigrid iteration for the corresponding steady state equations. Using a Fourier-Laplace analysis in two case studies, it is found that the multigrid performance on hyperbolic problems no longer shares the close resemblance in convergence factors between the WR iteration for parabolic equations and the iteration for the associated steady state equations.     

Pointwise convergence of the iterates of a harris-recurrent Markov operator

LetP be a Markov operator recurrent in the sense of Harris, withσ-finite invariant measureμ. (1) Ifμ is finite andP aperiodic, then forf ∈L ₁(μ),P ⁿf →f fdμ a.e. (2) Ifμ is infinite,P ⁿf → 0 a.e. for everyf ∈L _p (μ), 1≦p <∞.     

The change of the vibrational frequencies of a chemisorbed diatomic caused by the electrostatic interactions with the metal surface

Results of density functional calculations are used to discuss the change of the vibrational frequency of an adsorbed molecule caused by the electrostatic interaction between a chemisorbed molecule — simulated by two effective charges — and a metallic surface.     

A one-dimensional microscopic model for the rate of thermal desorption of an atom. The role of multiphonon processes

A one-dimensional microscopic model is used to calculate the desorption rate and to investigate the role of multiphonon processes in desorption. If the vibrational frequency of the chemisorptive bond is larger than the Debye frequency, multiphonon processes of all orders must be included as in our one-dimensional microscopic multiphonon model.     

Characterization and chemistry of polyaldehyde microspheres

The chemical composition of polyacrolein (PA) microspheres of various types as well as polyglutaraldehyde (PGL) microspheres was elucidated. Nephelometric measurements were used for studying the stability properties of the polyaldehyde microspheres in different pH and salt concentrations. The stability of the aldehyde groups themselves at various pH and temperature was also determined. The polyaldehyde microspheres covalently bind amino ligands, e.g., proteins, antibodies, enzymes, and drugs in a single step. The effect of temperature and the influence of thiol compounds on the reaction between the polyaldehyde microspheres and amino ligands was examined. The reaction of the polyaldehyde microspheres with sodium hydrogen sulfite is also described.     

From azides to nitriles. A novel fast transformation made possible by BrF3

[reaction: see text]. Various alkyl and aryl azides, readily obtained from halides or alcohols, were transformed into the corresponding nitriles using bromine trifluoride in moderate to good yields. The reaction is general and gives positive results with aliphatic, aromatic, cyclic, and functionalized azides. It can also be applied to the synthesis of optically active nitriles.