3,668 research outputs found
Low frequency creep in CoNiFe films
The results of an investigation of domain wall motion excited by slow rise-time, bipolar, hard-axis pulses in vacuum deposited CoNiFe films 1500A to 2000A thick are presented. The results are consistent with those of comparable NiFe films in spite of large differences in film properties. The present low frequency creep data together with previously published results in this and other laboratories can be accounted for by a model which requires that the wall structure change usually associated with low frequency creep be predominately a gyromagnetic process. The correctness of this model is reinforced by the observation that the wall coercive force, the planar wall mobility, and the occurrence of an abrupt wall structure change are the only properties closely correlated to the creep displacement characteristics of a planar wall in low dispersion films
Sexually charged: the views of gay and bisexual men on criminal prosecution for sexual HIV transmission
What do you need? 2007-08 findings from a national survey of people with diagnosed HIV
Over the past twenty-five years, both the needs of people with diagnosed HIV and our
understanding of them have changed dramatically. During this time there have been many
assessments of need, usually within specific geographic boundaries (such as Primary Care Trusts)
but no consistent approach to describing needs has been adopted. Most needs assessments have
been shaped by a variety of local factors, including the profile of existing services.
This study provides an insight into the needs of people with diagnosed HIV living in the UK, based
on a final sample of 1777 people. The approach taken to measuring and describing need is the same
as our previous national survey (Weatherburn et al. 2002). This approach was shaped by our earlier
qualitative studies exploring the experience of people with diagnosed HIV in the early days
of anti-HIV treatments (Anderson et al. 2000, Anderson & Weatherburn 1999, Anderson &
Weatherburn 1998).
While this study uses the same methods as our 2001-2002 survey we do not draw direct
comparisons with our previous data or discuss change over time. The limitations of self-completion
surveys using convenience samples make change comparisons hazardous. However, it is worth
noting that in any comparison with our prior data (Weatherburn et al. 2002) current levels of need
very rarely seem lower than we have previously reported.
The range and extent of medical and social care, support and information needs we present here
reveal significant challenges for service commissioners and providers. The first challenge is to avoid
drawing quick conclusions about what the patterns of need mean for service commissioning and
delivery. Needs have deliberately been separated from service use because the question of what
services are ‘needed’ cannot be answered simply by identifying the extent of personal needs. The
overall pattern of need is a useful starting point, but this pattern is complex
Signal Processing
Contains research objectives, summary of research and reports on two research projects.Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DAAB07-71-C-0300U. S. Coast Guard (Contract DOT-CG-13446-A
Equivalent Shock-Associated Noise Source Reconstruction of Screeching Underexpanded Unheated Round Jets
Signal Processing
Contains research objectives and reports on two research projects.Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DA 28-043-AMC-02536(E
The effects of changing chemistry on the shock response of basic polymers
The shock response of four common semicrystalline thermoplastic polymers—polyethylene (PE), polyvinylchloride (PVC), polytetrafluoroethylene (PTFE) and polychlorotrifluoroethylene (PCTFE)—have been studied in terms of their Hugoniots, release velocities and shear strengths. Through the variations in behaviour caused by changes to the attached atoms to the carbon backbone, it has been possible to suggest that there are two main factors in play. The first is an electrostatic repulsion between adjacent polymer chains. Where this force is large, for example in PTFE with highly electronegative fluorine atoms, this results in this force dominating the shock response, with low shock velocities, high release velocities and little if no hardening behind the shock front. In contrast, in materials such as PE, this force is now weaker, due to the lower electronegativity of hydrogen, and hence this force is easier to overcome by the applied shock stress. Now the main factor affecting shock behaviour is controlled by the shape of the polymer chain allowing inter chain tangling (tacticity). This results in higher shock velocities, lower release speeds and significant hardening behind the shock front as the chains are forced together. This is prevalent in materials with a relatively open structure such as PE and is enhanced with the presence of large side groups or atoms off the main polymer chain
Far-infrared spectroscopy of a lensed starburst: a blind redshift from Herschel
We report the redshift of HATLAS J132427.0+284452 (hereafter HATLAS J132427),
a gravitationally lensed starburst galaxy, the first determined 'blind' by the
Herschel Space Observatory. This is achieved via the detection of [C II]
consistent with z = 1.68 in a far-infrared spectrum taken with the SPIRE
Fourier Transform Spectrometer. We demonstrate that the [C II] redshift is
secure via detections of CO J = 2 - 1 and 3 - 2 using the Combined Array for
Research in Millimeter-wave Astronomy and the Institut de Radioastronomie
Millimetrique's Plateau de Bure Interferometer. The intrinsic properties appear
typical of high-redshift starbursts despite the high lensing-amplified fluxes,
proving the ability of the FTS to probe this population with the aid of
lensing. The blind detection of [C II] demonstrates the potential of the SAFARI
imaging spectrometer, proposed for the much more sensitive SPICA mission, to
determine redshifts of multiple dusty galaxies simultaneously without the
benefit of lensing.Comment: 6 pages, 5 figures, accepted for publication in MNRAS as a Lette
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