1,079,557 research outputs found
Gaussian Free Field in the background of correlated random clusters, formed by metallic nanoparticles
The effect of metallic nano-particles (MNPs) on the electrostatic potential
of a disordered 2D dielectric media is considered. The disorder in the media is
assumed to be white-noise Coulomb impurities with normal distribution. To
realize the correlations between the MNPs we have used the Ising model with an
artificial temperature that controls the number of MNPs as well as their
correlations. In the limit, one retrieves the Gaussian free
field (GFF), and in the finite temperature the problem is equivalent to a GFF
in iso-potential islands. The problem is argued to be equivalent to a
scale-invariant random surface with some critical exponents which vary with
and correspondingly are correlation-dependent. Two type of observables have
been considered: local and global quantities. We have observed that the MNPs
soften the random potential and reduce its statistical fluctuations. This
softening is observed in the local as well as the geometrical quantities. The
correlation function of the electrostatic and its total variance are observed
to be logarithmic just like the GFF, i.e. the roughness exponent remains zero
for all temperatures, whereas the proportionality constants scale with .
The fractal dimension of iso-potential lines (), the exponent of the
distribution function of the gyration radius (), and the loop lengths
(), and also the exponent of the loop Green function change in
terms of in a power-law fashion, with some critical exponents reported
in the text. Importantly we have observed that
, in which is the spin
correlation length in the Ising model
Neutron therapy of cancer
Reports relate applications of neutrons to the problem of cancer therapy. The biochemical and biophysical aspects of fast-neutron therapy, neutron-capture and neutron-conversion therapy with intermediate-range neutrons are presented. Also included is a computer program for neutron-gamma radiobiology
A Q-methodology study of parental understandings of infant immunisation : implications for health-care advice.
This study used Q-methodology to explore systematically parental judgements about infant immunisation. A total of 45 parents completed a 31-statement Q-sort. Data were collected after vaccination in general practitioner practices or a private day nursery. Q factor analysis revealed four distinct viewpoints: a duty to immunise based on medical benefits, child-orientated protection based on parental belief, concern and distress and surprise at non-compliance. Additionally, there was a common view among parents that they did not regret immunising their children. Implications of these results are discussed in terms of health-care policy and future research
Postbuckling behavior of graphite-epoxy panels
Structurally efficient fuselage panels are often designed to allow buckling to occur at applied loads below ultimate. Interest in applying graphite-epoxy materials to fuselage primary structure led to several studies of the post-buckling behavior of graphite-epoxy structural components. Studies of the postbuckling behavior of flat and curved, unstiffened and stiffened graphite-epoxy panels loaded in compression and shear were summarized. The response and failure characteristics of specimens studied experimentally were described, and analytical and experimental results were compared. The specimens tested in the studies described were fabricated from commercially available 0.005-inch-thick unidirectional graphite-fiber tapes preimpregnated with 350 F cure thermosetting epoxy resins
Theoretical and Observational Agreement on Mass Dependence of Cluster Life Times
Observations and N-body simulations both support a simple relation for the
disruption time of a cluster as a function of its mass of the form: t_dis = t_4
* (M/10^4 Msun)^gamma. The scaling factor t_4 seems to depend strongly on the
environment. Predictions and observations show that gamma ~ 0.64 +/- 0.06.
Assuming that t_dis ~ M^0.64 is caused by evaporation and shocking implies a
relation between the radius and the mass of a cluster of the form: r_h ~
M^0.07, which has been observed in a few galaxies. The suggested relation for
the disruption time implies that the lower mass end of the cluster initial mass
function will be disrupted faster than the higher mass end, which is needed to
evolve a young power law shaped mass function into the log-normal mass function
of old (globular) clusters.Comment: 2 pages, to appear in "The Formation and Evolution of Massive Young
Star Clusters", 17-21 November 2003, Cancun (Mexico
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