scholarly journals On the identification of the nonlinearity parameter in the Westervelt equation from boundary measurements

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Barbara Kaltenbacher ◽  
William Rundell
Keyword(s):  
Nonlinearity Parameter ◽  
Westervelt Equation ◽  
Boundary Measurements

Determination of nonlinearity parameter B/A of liquids by comparison with solutions of the three-dimensional Westervelt equation

2021 ◽  
Vol 150 (4) ◽  
pp. A125-A125
Author(s):  
Lonnie Chien ◽  
John M. Cormack ◽  
E. Carr Everbach ◽  
Mark F. Hamilton
Keyword(s):  
Three Dimensional ◽  
Nonlinearity Parameter ◽  
Westervelt Equation

scholarly journals Edge channels of broken-symmetry quantum Hall states in graphene visualized by atomic force microscopy

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sungmin Kim ◽  
Johannes Schwenk ◽  
Daniel Walkup ◽  
Yihang Zeng ◽  
Fereshte Ghahari ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Chemical Potential ◽  
Quantum Hall ◽  
Broken Symmetry ◽  
Topological Order ◽  
Edge States ◽  
Force Microscopy ◽  
Atomic Force ◽  
Intimate Relation ◽  
Boundary Measurements

AbstractThe quantum Hall (QH) effect, a topologically non-trivial quantum phase, expanded the concept of topological order in physics bringing into focus the intimate relation between the “bulk” topology and the edge states. The QH effect in graphene is distinguished by its four-fold degenerate zero energy Landau level (zLL), where the symmetry is broken by electron interactions on top of lattice-scale potentials. However, the broken-symmetry edge states have eluded spatial measurements. In this article, we spatially map the quantum Hall broken-symmetry edge states comprising the graphene zLL at integer filling factors of $${{\nu }}={{0}},\pm {{1}}$$ ν = 0 , ± 1 across the quantum Hall edge boundary using high-resolution atomic force microscopy (AFM) and show a gapped ground state proceeding from the bulk through to the QH edge boundary. Measurements of the chemical potential resolve the energies of the four-fold degenerate zLL as a function of magnetic field and show the interplay of the moiré superlattice potential of the graphene/boron nitride system and spin/valley symmetry-breaking effects in large magnetic fields.

q-BREATHERS IN FPU-LATTICES — SCALING AND PROPERTIES FOR LARGE SYSTEMS

2007 ◽  
Vol 21 (23n24) ◽  
pp. 3925-3932 ◽  
Author(s):  
SERGEJ FLACH ◽  
OLEG I. KANAKOV ◽  
KONSTANTIN G. MISHAGIN ◽  
MIKHAIL V. IVANCHENKO
Keyword(s):  
Energy Density ◽  
Normal Modes ◽  
Localization Length ◽  
Nonlinearity Parameter ◽  
First Finding ◽  
Nonlinear Lattices ◽  
Intensive Quantities ◽  
Time Periodic Solutions ◽  
Large Systems ◽  
Time Periodic

Recently q-breathers - time-periodic solutions which localize in the space of normal modes and maximize the energy density for some mode vector q0 - were obtained for finite nonlinear lattices. We scale these solutions to arbitrarily large lattices in various lattice dimensions. We study the scaling consequence for previously obtained analytical estimates of the localization length of q-breathers for β-FPU and α-FPU lattices. The first finding is that the degree of localization depends only on intensive quantities and is size independent. Secondly, a critical wave vector km is identified, which depends on one effective nonlinearity parameter, q-breathers minimize the localization length at k0 = km and completely delocalize in the limit k0 → 0, π.

Acceleration of the EM-like reconstruction method for diffuse optical tomography with ordered-subsets method

2014 ◽  
Vol 22 (3) ◽  
Author(s):  
Caifang Wang
Keyword(s):  
Numerical Experiments ◽  
Imaging Modality ◽  
Random Medium ◽  
Optical Tomography ◽  
Back Propagation ◽  
Three Dimensional ◽  
Diffuse Optical Tomography ◽  
Optical Parameters ◽  
Reconstruction Method ◽  
Boundary Measurements

Abstract.Diffuse optical tomography (DOT) is an optical imaging modality, which provides the spatial distribution of the optical parameters inside a random medium. A propagation back-propagation method named EM-like reconstruction method for stationary DOT problem has been proposed yet. This method is really time consuming. Hence the ordered-subsets (OS) technique for this reconstruction method is studied in this paper. The boundary measurements of DOT are grouped into nonoverlapping and overlapping ordered sequence of subsets with random partition, sequential partition and periodic partition, respectively. The performance of OS methods is compared with the standard EM-like reconstruction method with two-dimensional and three-dimensional numerical experiments. The numerical experiments indicate that reconstruction of nonoverlapping subsets with periodic partition, overlapping subsets with periodic partition and standard EM-like method provide very similar acceptable reconstruction results. However, reconstruction of nonoverlapping subsets with periodic partition spends a minimum of time to get proper results.

scholarly journals Significance of accurate diffraction corrections for the second harmonic wave in determining the acoustic nonlinearity parameter

AIP Advances ◽  
2015 ◽  
Vol 5 (9) ◽  
pp. 097179 ◽  
Author(s):  
Hyunjo Jeong ◽  
Shuzeng Zhang ◽  
Dan Barnard ◽  
Xiongbing Li
Keyword(s):  
Second Harmonic ◽  
Harmonic Wave ◽  
Nonlinearity Parameter ◽  
Acoustic Nonlinearity Parameter ◽  
Acoustic Nonlinearity

Effects of reconstructed magnetic field from sparse noisy boundary measurements on localization of active neural source

2015 ◽  
Vol 54 (1) ◽  
pp. 177-189 ◽  
Author(s):  
Hui-min Shen ◽  
Kok-Meng Lee ◽  
Liang Hu ◽  
Shaohui Foong ◽  
Xin Fu
Keyword(s):  
Magnetic Field ◽  
Boundary Measurements
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