112,078 research outputs found
LaFeAsOF: A low carrier density superconductor near itinerant magnetism
Full text linkDensity functional studies of 26K superconducting LaFeAs(O,F) are reported.
We find a low carrier density, high density of states, and modest
phonon frequencies relative to . The high leads to proximity to
itinerant magnetism, with competing ferromagnetic and antiferromagnetic
fluctuations and the balance between these controlled by doping level. Thus
LaFeAs(O,F) is in a unique class of high superconductors: high
ionic metals near magnetism.Comment: Shortened published form. Typos correcte
Testing a system specified using Statecharts and Z
Get PDFA hybrid specification language SZ, in which the dynamic behaviour of a system is described using Statecharts and the data and the data transformations are described using Z, has been developed for the specification of embedded systems. This paper describes an approach to testing from a deterministic sequential specification written in SZ. By considering the Z specifications of the operations, the extended finite state machine (EFSM) defined by the Statechart can be rewritten to produce an EFSM that has a number of properties that simplify test generation. Test generation algorithms are introduced and applied to an example. While this paper considers SZ specifications, the approaches described might be applied whenever the specification is an EFSM whose states and transitions are specified using a language similar to Z
Vacuum Insulation Panels (VIPs) for building construction industry - A review of the contemporary developments and future directions
Get PDFThis is the post-print version of the final paper published in Applied Energy. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2011 Elsevier B.V.Demand for energy efficient buildings has increased drastically in recent years and this trend will continue in the future. Insulating building elements will play a key role in meeting this demand by reducing heat losses through the building fabric. Due to their higher thermal resistance, Vacuum Insulation Panels (VIPs) would be a more energy efficient alternative to conventional building insulation materials. Thus, efforts to develop VIPs with characteristics suitable for applications to new and existing buildings are underway. This paper provides a review of important contemporary developments towards producing VIPs using various materials such as glass fibre, foams, perlite and fibre/powder composites. The limitations of the materials currently used to fabricate VIPs have not been emphasised in detail in previous review papers published. Selection criteria, methods to measure important properties of VIPs and analytical and numerical models presented in the past have been detailed. Limitations of currently employed design tools along with potential future materials such as Nano/microcellular foams and SiOx/SiNx coatings for use in VIPs are also described
Equation of state of bismuth to 222 GPa and comparison of gold and platinum pressure scales to 145 GPa
Get PDFThe equation-of-state (EoS) of bcc-bismuth was determined using the Pt pressure scale. Unit cell volumes of Bi, Pt, and Au were also measured simultaneously to megabar pressures by X-ray powder diffraction using a diamond anvil cell and a synchronus radiation source. The results suggest that Au pressure scale gave lower pressure than the Pt pressure scale
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