638 research outputs found
Unforeseen high temperature and humidity stability of FeCl intercalated few layer graphene
We present the first systematic study of the stability of the structure and
electrical properties of FeCl intercalated few-layer graphene to high
levels of humidity and high temperature. Complementary experimental techniques
such as electrical transport, high resolution transmission electron microscopy
and Raman spectroscopy conclusively demonstrate the unforeseen stability of
this transparent conductor to a relative humidity up to at room
temperature for 25 days, to a temperature up to 150\,^\circC in atmosphere
and up to a temperature as high as 620\,^\circC in vacuum, that is more than
twice higher than the temperature at which the intercalation is conducted. The
stability of FeCl intercalated few-layer graphene together with its unique
values of low square resistance and high optical transparency, makes this
material an attractive transparent conductor in future flexible electronic
applications.Comment: Scientific Reports, volume 5, article no. 760
What information can we obtain from the yield ratio in heavy-ion collisions ?
The recently reported data on the yield ratio in central
rapidity region of heavy-ion collisions are analyzed by theoretical formula
which accounts for Coulomb interaction between central charged fragment (CCF)
consisting of nearly stopped nucleons with effective charge
Z_{\mbox{\scriptsize eff}} and charged pions produced in the same region of
the phase space. The Coulomb wave function method is used instead of the usual
Gamow factor in order to account for the finite production range of pions,
. For Gaussian shape of the pion production sources it results in a
quasi-scaling in and Z_{\mbox{\scriptsize eff}} which makes
determination of parameters and Z_{\mbox{\scriptsize eff}} from the
existing experimental data difficult. Only sufficiently accurate data taken in
the extreme small - region, where this
quasi-scaling is broken, could be used for this purpose.Comment: 7 pages, Latex type, 8 figure
Observing Quark-Gluon Plasma with Strange Hadrons
We review the methods and results obtained in an analysis of the experimental
heavy ion collision research program at nuclear beam energy of 160-200A GeV. We
study strange, and more generally, hadronic particle production experimental
data. We discuss present expectations concerning how these observables will
perform at other collision energies. We also present the dynamical theory of
strangeness production and apply it to show that it agrees with available
experimental results. We describe strange hadron production from the
baryon-poor quark-gluon phase formed at much higher reaction energies, where
the abundance of strange baryons and antibaryons exceeds that of nonstrange
baryons and antibaryons.Comment: 39 journal pages (155kb text), 8 postscript figures, 8 table
Differential integrin expression regulates cell sensing of the matrix nanoscale geometry
Funding from Institute of Bioengineering (Queen Mary, University of London) and from the Engineering and Physical Sciences Research Council (EP/J501360/1) is gratefully acknowledged
Recoil Studies in the Reaction of 12-C Ions with the Enriched Isotope 118-Sn
The recoil properties of the product nuclei from the interaction of 2.2
GeV/nucleon 12-C ions from Nuclotron of the Laboratory of High Energies (LHE),
Joint Institute for Nuclear Research (JINR) at Dubna with a 118-Sn target have
been studied using catcher foils. The experimental data were analyzed using the
mathematical formalism of the standard two-step vector model. The results for
12-C ions are compared with those for deuterons and protons. Three different
Los Alamos versions of the Quark-Gluon String Model (LAQGSM) were used for
comparison with our experimental data.Comment: 10 pages, 6 figures, submitted to Nucl. Phys.
The multiple sclerosis risk sharing scheme monitoring study - early results and lessons for the future
Background: Risk sharing schemes represent an innovative and important approach to the problems of rationing and achieving cost-effectiveness in high cost or controversial health interventions. This study aimed to assess the feasibility of risk sharing schemes, looking at long term clinical outcomes, to determine the price at which high cost treatments would be acceptable to the NHS.
Methods: This case study of the first NHS risk sharing scheme, a long term prospective cohort study of beta interferon and glatiramer acetate in multiple sclerosis ( MS) patients in 71 specialist MS centres in UK NHS hospitals, recruited adults with relapsing forms of MS, meeting Association of British Neurologists (ABN) criteria for disease modifying therapy. Outcome measures were: success of recruitment and follow up over the first three years, analysis of baseline and initial follow up data and the prospect of estimating the long term cost-effectiveness of these treatments.
Results: Centres consented 5560 patients. Of the 4240 patients who had been in the study for a least one year, annual review data were available for 3730 (88.0%). Of the patients who had been in the study for at least two years and three years, subsequent annual review data were available for 2055 (78.5%) and 265 (71.8%) patients respectively. Baseline characteristics and a small but statistically significant progression of disease were similar to those reported in previous pivotal studies.
Conclusion: Successful recruitment, follow up and early data analysis suggest that risk sharing schemes should be able to deliver their objectives. However, important issues of analysis, and political and commercial conflicts of interest still need to be addressed
Two-kaon correlations in central Pb + Pb collisions at 158 A GeV/c
Two-particle interferometry of positive kaons is studied in Pb + Pb
collisions at mean transverse momenta and 0.91 GeV/c. A
three-dimensional analysis was applied to the lower data, while a
two-dimensional analysis was used for the higher data. We find that the
source size parameters are consistent with the scaling curve observed in
pion correlation measurements in the same collisions, and that the duration
time of kaon emission is consistent with zero within the experimental
sensitivity.Comment: 4 pages incl. 1 table and 3 fig's; RevTeX; accepted for publication
in PR
Enhancement of singly and multiply strangeness in p-Pb and Pb-Pb collisions at 158A GeV/c
The idea that the reduction of the strange quark suppression in string
fragmentation leads to the enhancement of strange particle yield in
nucleus-nucleus collisions is applied to study the singly and multiply strange
particle production in p-Pb and Pb-Pb collisions at 158A GeV/c. In this
mechanism the strange quark suppression factor is related to the effective
string tension, which increases in turn with the increase of the energy, of the
centrality and of the mass of colliding system. The WA97 observation that the
strange particle enhancement increases with the increasing of centrality and of
strange quark content in multiply strange particles in Pb-Pb collisions with
respect to p-Pb collisions was accounted reasonably.Comment: 8 pages, 3 PostScript figures, in Latex form. submitted to PR
Probing the equation of state in the AGS energy range with 3-d hydrodynamics
The effect of (i) the phase transition between a quark gluon plasma (QGP) and
a hadron gas and (ii) the number of resonance degrees of freedom in the
hadronic phase on the single inclusive distributions of 16 different types of
produced hadrons for Au+Au collisions at AGS energies is studied.
We have used an exact numerical solution of the relativistic hydrodynamical
equations without free parameters which, because of its 3-d character,
constitutes a considerable improvement over the classical Landau solution.
Using two different equations of state (eos) - one containing a phase
transition from QGP to the Hadronic Phase and two versions of a purely hadronic
eos - we find that the first one gives an overall better description of the
Au+Au experimental data at energies.
We reproduce and analyse measured meson and proton spectra and also make
predictions for anti-protons, deltas, anti-deltas and hyperons. The low m_t
enhancement in pi- spectra is explained by baryon number conservation and
strangeness equilibration.
We also find that negative kaon data are more sensitive to the eos, as well
as the K-/pi- ratio. All hyperons and deltas are sensitive to the presence of a
phase transition in the forward rapidity region. Anti-protons, Omegas and heavy
anti-baryons are sensitive in the whole rapidity range.Comment: 25 pages (.tex) and 9 figures (.ps
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