Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 24 for “"depinning"”.
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Plasticity as a depinning phase transition
… In this work we study plasticity as a pinning-depinning phase transition employing a discrete dislocation dynamics (DDD) model and a phase eld crystal (PFC) model in two dimensions. Below a critical ( ow) stress, the dislocations are pinned/jammed within their glide plane due to long-range …
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Measurement of the vortex depinning force in a high temperature superconductor
Introduction: Superconductivity is one of those subjects in physics that is as captivating theoretically as it is experimentally interesting. The dual driving force of commercial demand for high-temperature superconductors (HTSC's), coupled with the intense basic science interest in uncovering the …
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Depinning do fluxo de Josephson em compósitos YBa 2 Cu 3 O 7-delta/Ag
… de magnetização DC foram obtidas as linhas de depinning inicial e de irreversibilidade magnética em campo magnético aplicado até 120 Oe. O revestimento dos grãos supercondutores aparentemente não afeta a energia de acoplamento dos elos fracos entre os grãos e o potencial de pinning até 16.1 % …
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Dynamics of Driven Vortices in Disordered Type-II Superconductors
… (non-universal aging) and near the critical depinning region (universal aging); estimations of experimentally consistent critical scaling exponents for the continuous depinning phase transition of vortices in three dimensions; and an estimation of the boundary curve separating regions of …
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A Study of Narrowband Noise Characteristics Associated with Vortex Motion in High Temperature Superconductors
… at pinning then others, and therefore, above the depinning threshold, may effect the motion of vortices differently. To investigate their motion, voltage noise generated by moving vortices is studied for different material defect types using a nonequilibrium Metropolis Monte Carlo simulation. The …
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Hall effect in the superconducting and normal states in detwinned and twinned single crystals of zinc-doped YBa2Cu3O7-d
… affect vortex motion once the field exceeds the depinning one. The substantial increase of C2 and the Hall coefficient in the normal state by the detwinning points out that the disorder in the basal (or chain) plane is important for charge movement in the Cu02 plane, and the disorder affects the …
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Stick-slip behavior of liquid droplets on pillar-arrayed PDMS surfaces
… is synchronized with pillar pinning and depinning at the CL. The evidence of liquid residues on pillars left by passing droplet supports the hypothesis of micro-capillary bridges formation and rupture, which could be a dominant mechanism governing the stick-slip behavior of moving …
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Local imaging of magnetic flux in superconducting thin films
… Taken a 100 nm thin NbN film as an example, the depinning of vortices from natural defects under the influence of the force that the MFM tip exerts on the individual vortex was visualized and the local pinning force was estimated. The good agreement of these results with global transport …
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Effects of doping on the electronic properties of niobium triselenide
… of the resistivity and show that the CDW depinning process may be considered an example of a dynamic critical phenomenon.
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Magnetic properties of graphite and Bi2Sr2CaCu2O8+δ
… a further thickness dependent phenomenon on the depinning line (DL) of the flux line lattice of the high-Tc superconductor Bi2Sr2CaCu2O8+δ was studied. This geometrical effect shifts to notably lower temperatures in micrometer ring, compared with bulk crystals and thin flakes. The shift is …
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Low-dimensional purple and blue bronzes: Crystal growth, characterization and optical properties
… existence of a small-threshold field ET of CDW depinning in this sample. Hysteresis in resistivity, which has been detected in many CDW compounds, has been observed in our measurements and is associated with the instability of the CDW possibly due to the presence of defects.
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Nanophotonic Optomechanical Devices for Torque Magnetometry
… associated with single pinning and depinning events of a magnetic vortex core were observed. This optomechanical device increased torque magnetometer sensitivity by over an order of magnitude. The torque sensitivity of the device derives from the optimization of the optomechanical …
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Advanced materials for enhanced condensation heat transfer
… surfaces and identify a self-similar depinning mechanism governing adhesion on surfaces with multiple roughness length scales. We introduce the metric of pinned fraction to show how these surfaces must be designed to minimize adhesion. We then show how dropwise condensation on …
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Dynamic weakening and trained memory in avalanche dynamics from high-entropy alloys to neurons and spin systems
… and scale-invariant critical phenomena. A simple depinning theory provides a unifying framework for these behaviors, yet many systems deviate from pure criticality, exhibiting system-spanning runaways, characteristic length scales, and quasi-periodicity. Such deviations highlight the role of …
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Impact and Departure Dynamics of Droplets and Bubbles
… departure following the coalescence-induced depinning: capillary-inertial jumping for micrometric bubbles and a buoyant-inertial departure for millimetric ones. Eventually, this small bubble departure can delay film boiling which can be the barrier to the boiling heat transfer.
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An Investigation of the Structure, Pinning and Magnetoresistance of Domain Walls in Ni81Fe19 Planar Nanowires
… to the nanowire cross-sectional area, the DW depinning behaviour is relatively insensitive to notch geometry and instead is highly sensitive to wall type and chirality. A detailed model has been developed to make predictions for the AMR of individual DWs in nanowires. The model incorporates …
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Structure and dynamics of magnetic domain walls in multi-sublattice magnetic oxides
… experimental evidence. We investigated the DW depinning dynamics in Pt/BiYIG thin film, presenting a phase diagram of this pinning event, which proves the crucial role of minimizing the pinning effect in achieving fast DW velocity. In EuIG(110) thin film with strong in-plane anisotropy, we …
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Solid-liquid interactions in microscale structures and devices
… periodic oscillations due to regular pinning and depinning of the CL. Both the maximum and steady state forces are primarily dependent on area fractions of the micropatterned surfaces in our experiment. The resisting force is found to be proportional to the number of pillars which pin the CL at …
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Multiscale Simulations of Dynamics of Ferroelectric Domains
… non-linear creep-like region and a power-law depinning-like region. We propose a simple universal nucleation-and-growth-based analytical model that is able to quantify the dynamics of all types of domain walls in various ferroelectrics; this enables the prediction of the temperature- and …
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Non-universal behavior of intermittent flow in microplasticity
… includes the predictions of both the pinning/depinning transition and jamming/unjamming models. Similarly, the observed avalanche dynamics (avalanche velocities and their scaling with avalanche size, as well as averaged velocity-time profiles at fixed avalanche size or duration) are found to …
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