126 research outputs found
Equilibration of Quantum hall edges in symmetry broken bilayer graphene
Equilibration of quantum Hall edges is studied in a high quality dual gated
bilayer graphene device in both unipolar and bipolar regime when all the
degeneracies of the zero energy Landau level are completely lifted. We find
that in the unipolar regime when the filling factor under the top gate region
is higher than the back gate filling factor, the equilibration is partial based
on their spin polarization. However, the complete mixing of the edge states is
observed in the bipolar regime irrespective of their spin configurations due to
the Landau level collapsing at the sharp pn junction in our thin hBN (~ 15 nm)
encapsulated device, in consistent with the existing theory
Localization physics in graphene Moire superlattices
Non-trivial Berry phase of graphene leads to unusual quantum correction to
the conductivity. Berry phase of pi in single layer graphene (SLG) and 2pi in
bi-layer graphene (BLG) is expected to reveal weak anti-localization (WAL) and
weak localization (WL), respectively. However, experimentally both WAL and WL
have been observed in graphene devices depending on the strength of different
scattering mechanisms. Graphene superlattice having multiple Dirac cones is
expected to exhibit pi to 2pi Berry phase transition from primary Dirac cone
(PDC) to cloned Dirac cone (CDC). However, its effect on localization physics
has not been explored yet. In this letter we present the magneto-conductance
study in a hexagonal Boron-nitride (hBN)-graphene moire superlattice. Our
results reveal a transition from WAL at PDC to WL at CDC in a single device by
tuning the Fermi energy. The transition is supported by the quantum oscillation
measurements showing a shift of pi phase from PDC to CDC and corresponding
theoretical calculation capturing the Berry phase transition. Thus, our studies
on localization physics in graphene superlattice pave the way to understand the
carrier dynamics at multiple Dirac cones
Neglected fracture shaft femur presenting with pseudoaneurysm: a case report
A pseudoaneurysm is a collection of blood leaking from a damaged arterial wall. Development of the false aneurysm is due to either initial injury of the vessel or is a complication of internal fixation of the femoral fracture. Femoral artery pseudoaneurysms (FAPs) may close spontaneously if the tear is small enough to allow for clotting and sealing. On the other hand, rupture of the aneurysm can trigger thrombosis, distal embolization and compression of adjacent structures. We present a case of left superficial femoral arterial pseudoaneurysm in a 36-year-old male with fracture of left femoral shaft. A 36-year-old male with history of road traffic accident presented to our institute with pain and swelling in left thigh. Patient was investigated and diagnosed with fracture left femoral shaft with a pseudoaneurysm of the left superficial femoral artery (SFA). Stenting was done for SFA followed by open reduction and internal fixation of the femoral shaft fracture. Such cases require multidisciplinary approach and a proper planning with involvement of different medical specialities to achieve optimal results and to minimise any intraoperative and post operative complications
On the enhanced hardening ability and plasticity mechanisms in a novel Mn-added CoCrNi medium entropy alloy during high-pressure torsion
Microstructure and texture evolution during high-pressure torsion (HPT) of a novel Mn-added CoCrNi medium entropy alloy (Co33Ni33Cr19Mn15) is investigated for the first time. The alloy exhibited a rapid rise in hardness at relatively low shear strains (gamma <= 20). It is attributed to an extensive dislocation activity to achieve saturation in dislocation density of similar to 10(16) m(-2), combined TWIP and TRIP effects and microstructural refinement. At higher shear strain, hardness increased at much reduced rates owing to saturation of dislocation density, twin fault probability and the TRIP effect, besides continued grain refinement for severe nano-structuring led to subsequent strengthening. The FCC phase showed remarkable stability except a small degree of initial deformation-induced HCP martensitic transformation in an early stage of HPT. The ideal shear texture components were observed at low shear strain, and these continued to evolve up to 5 turns of HPT processing. For similar HPT processing conditions, the studied alloy showed superior hardness (similar to 650 Hv) compared to a wide spectrum of FCC materials, which is ascribed to a combination of the strengthening mechanisms of Taylor hardening, the TRIP and TWIP effects and Hall-Petch strengthening resulting from the nano-structured grains having an average size of similar to 35 nm. (c) 2022 The Author(s). Published by Elsevier B.V. CC_BY_4.
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The Multifractal Detrended Fluctuation Analysis (Mf-Dfa) and Anomalies in Geomagnetic Total Field Intensity Prior To Mw~5.5 Earthquake
193-197In the research article, we report the anomalies observed in geomagnetic total field intensity (BTotal) prior to Mw 5.5 Kokrajhar event. The multifractal analysis was scrutinized to reveal the underlying dynamics in the Geomagnetic Total field intensity time series. The multifractal spectrum on the day when the event occurred (TEvent day) and its surrogate (TSurrogate) was investigated to understand the behavior and dynamics hidden in BTotal time series. A significant variation in the multifractal spectrum was observed between TDay one (multifractal spectrum a day prior to the event) and TEvent day. It was also observed that the mulfractality of BTotal when the event occurred (TEvent day) got stronger than the multifractality of TDay one and was sourced from low values distribution. The multifractality in TDay one and TEvent day time series was not from source type long range correlation or sourced from broad probability density function. The investigation also manifests some non-linear features which probably evinces the anomalies to be seismic induced. The observations are elaborately emphasized in the article. The study scrutinizes the underlying dynamics in geomagnetic field intensity time series for earthquake precursory and forecast studies
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