24,420 research outputs found
Work Function of Single-wall Silicon Carbide Nanotube
Using first-principles calculations, we study the work function of single
wall silicon carbide nanotube (SiCNT). The work function is found to be highly
dependent on the tube chirality and diameter. It increases with decreasing the
tube diameter. The work function of zigzag SiCNT is always larger than that of
armchair SiCNT. We reveal that the difference between the work function of
zigzag and armchair SiCNT comes from their different intrinsic electronic
structures, for which the singly degenerate energy band above the Fermi level
of zigzag SiCNT is specifically responsible. Our finding offers potential
usages of SiCNT in field-emission devices.Comment: 3 pages, 3 figure
Nodeless superconductivity in IrPtTe with strong spin-orbital coupling
The thermal conductivity of superconductor IrPtTe
( = 0.05) single crystal with strong spin-orbital coupling was measured down
to 50 mK. The residual linear term is negligible in zero magnetic
field. In low magnetic field, shows a slow field dependence. These
results demonstrate that the superconducting gap of IrPtTe is
nodeless, and the pairing symmetry is likely conventional s-wave, despite the
existence of strong spin-orbital coupling and a quantum critical point.Comment: 5 pages, 4 figure
S-shaped flow curves of shear thickening suspensions: Direct observation of frictional rheology
We study the rheological behavior of concentrated granular suspensions of
simple spherical particles. Under controlled stress, the system exhibits an
S-shaped flow curve (stress vs. shear rate) with a negative slope in between
the low-viscosity Newtonian regime and the shear thickened regime. Under
controlled shear rate, a discontinuous transition between the two states is
observed. Stress visualization experiments with a novel fluorescent probe
suggest that friction is at the origin of shear thickening. Stress
visualization shows that the stress in the system remains homogeneous (no shear
banding) if a stress is imposed that is intermediate between the high and
low-stress branches. The S-shaped shear thickening is then due to the
discontinuous formation of a frictional force network between particles upon
increasing the stress.Comment: 5 pages + 6 figure
Binomial coefficients, Catalan numbers and Lucas quotients
Let be an odd prime and let be integers with and . In this paper we determine
mod for ; for example,
where is the Jacobi symbol, and is the Lucas
sequence given by , and for
. As an application, we determine modulo for any integer , where denotes the
Catalan number . We also pose some related conjectures.Comment: 24 pages. Correct few typo
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