Stepwise Replication of a Tröger's Base Analogue

Redox-controlled covalent templating and macrocyclization underlie a novel scheme for stepwise exponential self-replication. This process has been demonstrated by using Tr?ger's base analogue 1 as the template.     

Plasma-liquid technologies for treatment of archaelogical artifacts

Plasma-liquid technologies at atmospheric pressure provide a wide range of possibilities for applications. One of them, the treatment of archaeological artifacts, is presented in this paper. The effects of discharges between a metal electrode and a solution surface and/or an interaction of hollow cathode plasma jet, plasma pencil, with liquid on the corroded surface of bronze and glass artifacts were studied. It was compared with standard low pressure plasma techniques and with the effects of electrolysis. Original and treated objects were characterized by means of scanning electron microscope (SEM) with energy dispersive analyser used for the spot elemental analyses.     

Jacobi matrices with absolutely continuous spectrum

Let be a Jacobi matrix defined in as , where is a unilateral weighted shift with nonzero weights such that Define the seqences: If and , then has an absolutely continuous spectrum covering . Moreover, the asymptotics of the solution is also given.

     

Normal bases via general Gauss periods

Gauss periods have been used successfully as a tool for constructing normal bases in finite fields. Starting from a primitive th root of unity, one obtains under certain conditions a normal basis for over , where is a prime and for some integer . We generalize this construction by allowing arbitrary integers with , and find in many cases smaller values of than is possible with the previously known approach.

     

Canonical hadron gas interpretation ofp-A E802 data

Hadron gas models have proved successful in predicting particle production in relativistic nucleus-nucleus collisions. The extension of these models to the smaller systems formed in proton-nucleus collisions requires that the finite size of the system be considered. We study two features introduced by the finite size: the need to conserve strangeness and baryon number exactly by performing calculations in the canonical ensemble, and the inclusion of a finite size geometrical correction term in the single particle density of states. We find significant differences between the grand canonical and canonical ensembles and a strong dependence on the baryon number of the system.     

Pauli exchange effects in the elastic scattering of O + O

The real optical potential for ¹⁶O+¹⁶O system is calculated within a generalized version of the double-folding model with the Pauli knock-on exchange effects between the projectile nucleons and the target nucleons taken into account from first principle. The elastic scattering data at E_lab=350 MeV supplemented by the new measurement at larger angles seem to be the first case in heavy-ion scattering where one can test the reliability of different theoretical heavy-ion optical potentials. Predictions are made for the elastic scattering of ¹⁶O+¹⁶O at laboratory energies of 240–480 MeV to illustrare the energy dependence of the rainbow structure which has been clearly observed in experiment at 350 MeV.     

Acceleration of femtosecond pulses to superluminal velocities by Gouy phase shift

The phase and the group velocities are calculated in a three-dimensional neighbourhood of the focus of an aberration-free lens illuminated by a spatially Gaussian beam. The Gouy phase shift caused by the diffraction results in superluminal pulse propagation on the optical axis within the Rayleigh range.     

Preparation of a novel HALS polypropylene stabilizer

The radiation induced graft copolymerization of m-isopropenyl-α,α-dimethyl benzyl iso-cyanate (m-TMI) and styrene onto polypropylene was carried out. The extent of grafting increased with increasing amount of styrene and with increased radiation dose. A graft load of 180% was obtained by immersing a 50 kGy pre-irradiated film in a monomer solution containing 25 mol % m-TMI and 75 mol % styrene. The graft copolymer is suitable for covalently binding nonpolymerizable stabilizers with a suitable nucleophilic moiety. In this work the isocyanate moiety of the graft copolymer was allowed to react with 4-amino-2,2,6,6-tetramethyl piperidine, a hindered amine light stabilizer. Fourier trans-formed infrared spectroscopy confirmed the formation of an urea moiety. © 1995 John Wiley & Sons, Inc.