Acceptor-like deep level defects in ion-implanted ZnO

N-type ZnO samples have been implanted with MeV Zn⁺ ions at room temperature to doses between 1×10⁸ and 2×10¹⁰cm⁻², and the defect evolution has been studied by capacitance-voltage and deep level transient spectroscopy measurements. The results show a dose dependent compensation by acceptor-like defects along the implantation depth profile, and at least four ion-induced deep-level defects arise, where two levels with energy positions of 1.06 and 1.2 eV below the conduction band increase linearly with ion dose and are attributed to intrinsic defects. Moreover, a re-distribution of defects as a function of depth is observed already at temperatures below 400 K.This work was supported by the Norwegian Research Council through the Frienergi program and the Australian Research Council through the Discovery projects program

Hanbury Brown and Twiss correlations in atoms scattered from colliding condensates

Low energy elastic scattering between clouds of Bose condensed atoms leads to the well known s-wave halo with atoms emerging in all directions from the collision zone. In this paper we discuss the emergence of Hanbury Brown and Twiss coincidences between atoms scattered in nearly parallel directions. We develop a simple model that explains the observations in terms of an interference involving two pairs of atoms each associated with the elementary s wave scattering process.Comment: Minor corrections. reference update

Chiral symmetry breaking in a uniform external magnetic field II. Symmetry restoration at high temperatures and chemical potentials

Chiral symmetry is dynamically broken in quenched, ladder QED at weak gauge couplings when an external magnetic field is present. In this paper, we show that chiral symmetry is restored above a critical chemical potential and the corresponding phase transition is of first order. In contrast, the chiral symmetry restoration at high temperatures (and at zero chemical potential) is a second order phase transition.Comment: Latex; 12 pages; 8 postscript figures include

Trade union strategy in Sydney's construction union: a Roman Catholic perspective

Rudd Government ministers have talked tough towards the more militant Australian trade unions since coming to office in November 2007. However, despite this, it is still fair to say that the removal of the Howard-Costello Government reduced neo-liberal hegemony by altering the invisible balance of power between capital and labour in the construction industry. Using a set of case studies, based on data obtained from fieldwork at the New South Wales, Australia branch of the Construction Forestry Mining and Energy Union (CFMEU), we document key elements of union strategy at the branch level in the year immediately after the removal of the Howard-Costello Government. A key aspect of branch level strategy was building site visits by a team of organisers, led by the divisional state secretary, designed to rebuild influence on site and reconnect with workers. Furthermore, the CFMEU’s hiring of foreign language speaking organisers and production of foreign language publications is a praiseworthy attempt to reach out to ethnic minority workers and bring them under the ‘mainstream’ union umbrella. We use a theory framework of Roman Catholic social teaching to frame our discussions

The liability of dentists in the provision of dental materials

AnalysisDental practitioners are thought to be subject to the same principles in relation to the tort of negligence as are medical practitioners. However, in addition to their common law liability, dental practitioners may be more vulnerable to strict liability under the Sale of Goods Ordinance because, unlike medical practitioners, provision of materials is a large part of dental practice. The classification of the provision of dental materials to patients can affect the potential liability of dentists, ie whether there is a contract for the supply of goods, for the supply of services, or something else. This article explores the implications of the Sale of Goods Ordinance and the impact of reforms recently recommended by the Law Reform Commission of Hong Kong on dental practitioners in Hong Kong.published_or_final_versio

The role of the intervertebral disc niche on embryonic stem cell differentiation and intervertebral disc regeneration

Poster Session - Orthopedic Regeneration: no. 91DMM 2011 entitled: Re-engineering Regenerative MedicineThe intervertebral disc (IVD) is a highly specialised environment, where cell, water and proteoglycan decrease is strongly associated with disc degeneration, which can lead to back pain. We postulate that the IVD niche is a major factor for IVD cell development and maintenance, and can play a role in progenitor differentiation to become disc cells. The understanding of how stem/progenitor cells develop into IVD cells could potentially facilitate the development of regenerative therapies for degenerated IVD. Here, we aim to introduce human embryonic stem cells (ESCs) into the IVD environment using a model of decellularised bovine disc, and examine how the IVD niche impacts on phenotypic changes in vitro using …postprin

Singular behaviour of the electromagnetic field

The singularities of the electromagnetic field are derived to include all the point-like multipoles representing an electric charge and current distribution. Firstly derived in the static case, the result is generalized to the dynamic one. We establish a simple procedure for passing from the first, to the second case.Comment: Latex, 21.pages, no figure

Nanoindentation-induced deformation of Ge

The deformation mechanisms of crystalline (100) Ge were studied using nanoindentation, cross sectional transmission electron microscopy (XTEM) and Raman microspectroscopy. For a wide range of indentation conditions using both spherical and pointed indenters, multiple discontinuities were found in the force–displacement curves on loading, but no discontinuities were found on unloading. Raman microspectroscopy, measured from samples which had plastically deformed on loading, showed a spectrum shift from that in pristine Ge, suggesting only residual strain. No evidence (such as extra Raman bands) was found to suggest that any pressure-induced phase transformations had occurred, despite the fact that the material had undergone severe plastic deformation.Selected area diffraction pattern studies of the mechanically damaged regions also confirmed the absence of additional phases. Moreover, XTEM showed that, at low loads, plastic deformation occurs by twinning and dislocation motion. This indicates that the hardness of Gemeasured by indentation is not primarily dominated by phase transformation, rather by the nucleation and propagation of twin bands and/or dislocations