Cyclicity of the adjoint of weighted composition operators on the hilbert space of analytic functions

In this paper, we discuss the hypercyclicity, supercyclicity and cyclicity of the adjoint of a weighted composition operator on a Hilbert space of analytic functions.     

A ruled residue theorem for function fields of conics

The ruled residue theorem characterises residue field extensions for valuations on a rational function field. Under the assumption that the characteristic of the residue field is different from 2 this theorem is extended here to function fields of conics. The main result is that there is at most one extension of a valuation on the base field to the function field of a conic for which the residue field extension is transcendental but not ruled. Furthermore the situation when this valuation is present is characterised.     

An asymptotic formula for the voltage potential in the case of a near-surface conductivity inclusion

We rigorously derive an asymptotic expansion of the steady-state voltage potentials in the presence of a conductivity inclusion of small volume that is close to a planar surface. This new formula is motivated by the practically important inverse problem of imaging a conductivity inclusion near a planar interface. Partly supported by ACI Jeunes Chercheurs (0693) from the Ministry of Education and Scientific Research, France. Partially supported by grant R02-2003-000-10012-0 from the Korea Science and Engineering Foundation. Received: December 2, 2003; revised: January 18, 2004     

YCu3Al2, an example of an AB5 structure type

Yttrium tricopper dialuminium, YCu₃Al₂, is isostructural with hexagonal CaCu₅, in which each Cu atom at the 3g(½,0,½) position in space group P6/mmm (No. 191) is partially replaced by an Al atom. The hydrogen‐uptake properties are usually enhanced in other AB₅ structures by aluminium substitution. YCu₅ does not show any hydrogen absorption, and the goal of the present work is to investigate whether aluminium substitution could expand the metal‐atom lattice enough to provide better interstitial positions for hydrogen storage. However, no enthalpy change was observed up to 773 K under 3 MPa static H₂ pressure by differential thermal analysis (DTA) for the title compound. The compound does not show any significant hydrogen absorption/desorption in the pressure‐composition isotherms (P–C–T diagrams) in the temperature range 298–673 K under 3.3 MPa H₂ pressure.     

Determination of nanomole quantities of lower aldehydes by cold-vapour atomic absorption spectrometry

A method is described for the determination of 10–100 nmole of methanal and 20–150 nmole of ethanal and propanal. The method is based on the oxidation of aldehydes to the corresponding acids by mercuric ion which in turn is reduced to elemental mercury, followed by cold-vapour atomic absorption spectrometry. Calibration plots were constructed between the concentration of each aldehyde and absorbance, while the calibration from the conventional cold vapour procedure was used for total aldehydes determination. The method is selective and can be used for aldehyde determination in the presence of ketones, acetals, alcohols, acids, esters, ethers, organic chlorides and epoxides. This simple method is characterised by 98–102% recoveries and standard deviations of 3%.     

Inclusive strange particle production in π+p interactions at 16 GeV/c

The production of $\text{K}{}_{\mathrm{S}}{}^0\text{, Λ}\text{and}\text{Λ}$ is measured in π⁺p reactions at 16 GeV/c. The total strange particle cross section is found to be 4.0 ± 0.3 mb, about 20% of the inelastic cross section. Cross sections for single strange particles and for strange particle pairs are determined, both inclusively and as functions of the charged multiplicity. Relative production rates for different strange particle combinations are compared with the prediction of the isospin statistical model. Inclusive spectra for single particles are studied and it is found the K_S⁰ are produced mostly in the forward hemisphere, most probably by fragmentation of the incident pion into $\text{K}\text{K}\text{π}$. The Λ are mostly backwards, probably deriving from fragmentation of the proton into ΛK pairs. The $\text{Λ}$ tend to be produced forwards, but evidence is found for central $\text{Λ}\text{Λ}$ production. Distributions in rapidity of the Λ particles from π⁺p interactions are compared in terms of the factorisation hypothesis. Results are given on the Λ transversal polarisation.     

A chemical method for the convenient surface functionalisation of polymers

A method for the application of carbenes as reactive intermediates for surface modification of polymeric substrates has been developed; the efficacy of the process has been demonstrated by irreversible dyeing of polystyrene, polythene, nylon, silica, and controlled pore glass, and to a limited extent, polytetrafluoroethylene.