12,192 research outputs found
Acceptor-like deep level defects in ion-implanted ZnO
N-type ZnO samples have been implanted with MeV Znâș ions at room temperature to doses between 1Ă10âž and 2Ă10Âčâ°cmâ»ÂČ, 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 1.2âeV 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 400âK.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 CFMEUâs 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 âmainstreamâ 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 âŠpostprin
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 forceâdisplacement 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
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