3,776 research outputs found
Negative to Positive Magnetoresistance transition in Functionalization of Carbon nanotube and Polyaniline Composite
Electrical resistivity and magnetoresistance(MR) in polyaniline(PANI) with
carbon nanotube(CNT) and functionalized carbon nanotube(fCNT) composites have
been studied for different weight percentage down to the temperature 4.2K and
up to magnetic field 5T. Resistivity increases significantly in composite at
low temperature due to functionalization of CNT compare to only CNT.
Interestingly transition from negative to positive magnetoresistance has been
observed for 10wt% of composite as the effect of disorder is more in fCNT/PANI.
This result depicts that the MR has strong dependency on disorder in the
composite system. The transition of MR has been explained in the basis of
polaron-bipolaron model. The long range Coulomb interaction between two
polarons screened by disorder in the composite of fCNT/PANI, increases the
effective on-site Coulomb repulsion energy to form bipolaron which leads to
change the sign of MR from negative to positive.Comment: 5 pages, 8 figures; typos adde
Gluonic Dissociation Revisited : I. Fugacity, Flux And Formation Time Effects
We revisit the standard treatment [Xu, Kharzeev, Satz and Wang, Phys. Rev. C
{\bf 53}, 3051 (1996)] of suppression due to gluonic bombardment in an
equilibrating quark-gluon plasma. Effects arising from gluon fugacity, relative
flux, and meson formation time are correctly incorporated in
the formulation of the gluon number density, velocity-weighted cross section,
and the survival probability. Our new formulae are applied to numerically study
the pattern of suppression in the central rapidity region at RHIC/LHC
energies. The temperature and transverse momentum dependence of our graphs have
noticeable differences from those of Xu et al.Comment: 15 pages, 6 figure
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