Density-functional theory study on the arrangement of adsorbed formate molecules on Cu(110)

The interaction of formate molecules with the Cu(110) surface is investigated using density-functional theory calculations. We find that in the most stable structures for low and high coverage, the formate molecules are sitting perpendicular to the Cu(110) surface, and they are adsorbed in a bridge position, i.e., the O-C-O group forms a bridge between two Cu atoms. Other tested configurations are less stable by at least 0.45 eV per formate molecule. In the case of an oxygen-precovered Cu(110) surface with high formate coverage [two molecules in a (2x2) unit cell] we find a very similar adsorption geometry. We find an attractive interaction between adsorbed formate molecules on the copper surface. Our results are consistent with experimental results by scanning tunneling microscopy and photoelectron diffraction

An exploration of the attitudes and perceptions of the UK public towards self-care for minor ailments

Aims and objectives: The purpose of this pilot study was to explore the attitudes and perceptions of members of the UK public towards self-care for minor ailments. Background: With an ageing and increasing population, and a National Health Service in extremis with plummeting performance indicators and the huge disparity between available funding and costs of treatments, methods to reduce demand upon health services are key. Increasing the use of self-care for minor ailments is one way in which this pressure could be alleviated. Design + Method: This study utilised qualitative methods including semi-structured telephone interviews. This data was then valuated, and key themes are drawn out of the data using thematic analysis. Findings: The results showed that the public are aware of the notion of self-care, and some are engaging with it. However, for a number of reasons, patients are still likely to want a face to face appointment despite the use of internet and telephone advice services. Conclusion: The study highlighted that there are multifactorial aspects impacting upon a patient’s likelihood to engage in self-care when faced with a minor illness. The results are not generalisable to every member of the UK public, but interesting questions are raised with regards to the usefulness of current public health messages being portrayed across various media when there appears to be a lack of desire from the public to use some recommended services

Cd-vacancy and Cd-interstitial complexes in Si and Ge

The electrical field gradient (EFG), measured e.g. in perturbed angular correlation (PAC) experiments, gives particularly useful information about the interaction of probe atoms like 111In / 111Cd with other defects. The interpretation of the EFG is, however, a difficult task. This paper aims at understanding the interaction of Cd impurities with vacancies and interstitials in Si and Ge, which represents a controversial issue. We apply two complementary ab initio methods in the framework of density functional theory (DFT), (i) the all electron Korringa-Kohn-Rostoker (KKR) Greenfunction method and (ii) the Pseudopotential-Plane-Wave (PPW) method, to search for the correct local geometry. Surprisingly we find that both in Si and Ge the substitutional Cd-vacancy complex is unstable and relaxes to a split-vacancy complex with the Cd on the bond-center site. This complex has a very small EFG, allowing a unique assignment of the small measured EFGs of 54MHz in Ge and 28MHz in Si. Also, for the Cd-selfinterstitial complex we obtain a highly symmetrical split configuration with large EFGs, being in reasonable agreement with experiments

Generation of multi-modal dialogue for a net environment

In this paper an architecture and special purpose markup language for simulated affective face-to-face communication is presented. In systems based on this architecture, users will be able to watch embodied conversational agents interact with each other in virtual locations on the internet. The markup language, or Rich Representation Language (RRL), has been designed to provide an integrated representation of speech, gesture, posture and facial animation

Metal-Ferroelectric-Metal heterostructures with Schottky contacts I. Influence of the ferroelectric properties

A model for Metal-Ferroelectric-Metal structures with Schottky contacts is proposed. The model adapts the general theories of metal-semiconductor rectifying contacts for the particular case of metal-ferroelectric contact by introducing: the ferroelectric polarization as a sheet of surface charge located at a finite distance from the electrode interface; a deep trapping level of high concentration; the static and dynamic values of the dielectric constant. Consequences of the proposed model on relevant quantities of the Schottky contact such as built-in voltage, charge density and depletion width, as well as on the interpretation of the current-voltage and capacitance-voltage characteristics are discussed in detail.Comment: 14 pages with 4 figures, manuscript under revision at Journal of Applied Physics for more than 1 year (submitted May 2004, first revision September 2004, second revision May 2005

Comparison of Measured and Calculated Specific Resistances of Pd/Pt Interfaces

We compare specific resistances (AR equals area A times resistance R) of sputtered Pd/Pt interfaces measured in two different ways with no-free-parameter calculations. One way gives 2AR(Pd/Pt) of 0.29 (0.03) fohm-m(2) and the other 0.17 (0.13) fohm-m(2). From these we derive a best estimate of 2AR(Pd/Pt) of 0.28 (0.06) fohm-m(2), which overlaps with no-free-parameter calculations: 2AR(predicted) of 0.30 (0.04) fohm-m(2) for flat, perfect interfaces, or 0.33 (0.04) fohm-m(2) for interfaces composed of 2 monolayers of a 50percent-50percent PdPt alloy. These results support three prior examples of agreement between calculations and measurements for pairs of metals having the same crystal structure and the same lattice parameter to within 1 percent. We also estimate the spin-flipping probability at Pd/Pt interfaces as 0.13 (0.08).Comment: 3 pages, 3 figures, submitted for publication New version has corrected value of delta(Pd/Pt

Making Sense of the Legendre Transform

The Legendre transform is an important tool in theoretical physics, playing a critical role in classical mechanics, statistical mechanics, and thermodynamics. Yet, in typical undergraduate or graduate courses, the power of motivation and elegance of the method are often missing, unlike the treatments frequently enjoyed by Fourier transforms. We review and modify the presentation of Legendre transforms in a way that explicates the formal mathematics, resulting in manifestly symmetric equations, thereby clarifying the structure of the transform algebraically and geometrically. Then we bring in the physics to motivate the transform as a way of choosing independent variables that are more easily controlled. We demonstrate how the Legendre transform arises naturally from statistical mechanics and show how the use of dimensionless thermodynamic potentials leads to more natural and symmetric relations.Comment: 11 pages, 3 figure