166 research outputs found
Residual resistivity due to wedge disclination dipoles in metals with rotational plasticity
The residual resistivity in metals caused by wedge disclination
dipoles is studied in the framework of the Drude formula. It is shown that
with for biaxial and for uniaxial dipoles ( is
a size of dipole arm)Comment: 12 pages, 2 figure
Stiffening thermal membranes by cutting
Two-dimensional crystalline membranes have recently been realized
experimentally in such systems as graphene and molybdenum disulfide, sparking a
resurgence in interest in their statistical properties. Thermal fluctuations
can significantly affect the effective mechanical properties of properly
thermalized membranes, renormalizing both bending rigidity and elastic moduli
so that in particular they become stiffer to bending than their bare bending
rigidity would suggest. We use molecular dynamics simulations to examine how
the mechanical behavior of thermalized two-dimensional clamped ribbons
(cantilevers) depends on their precise topology and geometry. We find that a
simple slit smooths roughness as measured by the variance of height
fluctuations. This counterintuitive effect may be due to the counter-posed
coupling of the lips of the slit to twist in the intact regions of the ribbon.Comment: 7 page
Self-supporting graphene films and their applications
The self-supporting monolayer material which is graphene has excited enormous interest over the ten years since its discovery due to its remarkable electrical, mechanical thermal and chemical properties. In this paper we describe our work to develop chemical vapour deposition methods to grow monolayer graphene on copper foil substrates and the subsequent transfer process. Raman microscopy, scanning electron microscopy and atomic force microscopy (AFM) are used to examine the quality of the transferred material. To demonstrate the process we describe transfer onto patterned SiO2/Si substrates which forms freely suspended graphene with focus on circular wells forming graphene drums. These show interesting mechanical properties which are being explored as nanomechanical resonators.UK NMS Programme, the EU EMRP (European Metrology Research Programme) projects MetNEMS and GraphOh
Effect of elastic distortions on solid-state amorphization at grain boundaries and dislocations
Emission of partial dislocations from triple junctions of grain boundaries in nanocrystalline materials
- …