7,342 research outputs found
Chiral tunneling in trilayer graphene
We study the effect of chiral-tunneling in Bernal and Rombhohedral stacked
trilayer-graphene (3LG). Based on the chirality of the electronic bands, at the
K-point, (Rombhohedral) Bernal-3LG exhibits 100% (50%) transparency across a
heterojunction. Utilizing this property, we further investigate the effect of
electron collimation in 3LG. Due to the difference in the Berry's phase, we
show that, Rombhohedral-3LG is a better electron collimator, compared to
monolayer and Bernal-bilayer graphene. Since, Bernal-3LG can be decomposed into
two separate channels consisting of a monolayer and a modified Bernal-bilayer
graphene; the Bernal-3LG is weaker electron collimator, compared to
Rombhohedral-3LG.Comment: APL, 2012; http://dx.doi.org/10.1063/1.370375
FDM preparation of bio-compatible UHMWPE polymer for artificial implant
Due to its properties of high wear, creep resistance, high stiffness and strength, Ultra-High Molecular Weight Polyethylene (UHMWPE) was developed to eliminate most metallic wear in artificial implant, which conventionally found in stainless steel, Cobalt Chromium (Co-Cr) and Titanium (Ti) alloys. UHMWPE has an ultra-high viscosity that renders continuous melt-state processes including one of the additive manufacturing processes, Fused Deposition Modeling (FDM) ineffective for making UHMWPE implant. Attempt to overcome this problem and adapting this material to FDM is by blending UHMWPE with other polyethylene including High Density Polyethylene (HDPE) and Polyethylene-Glycol (PEG) which provide adequate mechanical properties for biomedical application along with the improvement in extrudability. It was demonstrated that the inclusion of 60% HDPE fraction has improved the flowability of UHMWPE in MFI test and showing adequate thermal stability in TGA
Improved filters for gravitational waves from inspiraling compact binaries
The order of the post-Newtonian expansion needed to extract in a reliable and accurate manner the fully general relativistic gravitational wave signal from inspiraling compact binaries is explored. A class of approximate wave forms, called P-approximants, is constructed based on the following two inputs: (a) the introduction of two new energy-type and flux-type functions e(v) and f(v), respectively, (b) the systematic use of the Padé approximation for constructing successive approximants of e(v) and f(v). The new P-approximants are not only more effectual (larger overlaps) and more faithful (smaller biases) than the standard Taylor approximants, but also converge faster and monotonically. The presently available (v/c)^5-accurate post-Newtonian results can be used to construct P-approximate wave forms that provide overlaps with the exact wave form larger than 96.5%, implying that more than 90% of potential events can be detected with the aid of P-approximants as opposed to a mere 10–15 % that would be detectable using standard post-Newtonian approximants
Necessary misapplications: the work of translation in performance in an era of global asymmetries
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