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High diffusion-sensitizing magnetic field gradients have been more and more often applied nowadays to achieve a better characterization of the microstructure. As the resulting spin-echo signal significantly deviates from the conventional…

Statistical Mechanics · Physics 2021-10-14 N. Moutal , D. S. Grebenkov

The Bloch-Torrey equation governs the evolution of the transverse magnetization in diffusion magnetic resonance imaging, where two mechanisms are at play: diffusion of spins (Laplacian term) and their precession in a magnetic field gradient…

Computational Physics · Physics 2021-10-14 Nicolas Moutal , Antoine Moutal , Denis S. Grebenkov

We discuss some challenges and recent advances in understanding the macroscopic signal formation at high non-narrow magnetic field gradients at which both the narrow pulse and the Gaussian phase approximations fail. The transverse…

Medical Physics · Physics 2019-11-06 Denis S. Grebenkov

In this paper, we discuss the transport phenomena of electromagnetic waves in a two-dimensional random system which is composed of arrays of electrical dipoles, following the model presented earlier by Erdogan, et al. (J. Opt. Soc. Am. B…

Soft Condensed Matter · Physics 2009-11-10 Ken Wang , Zhen Ye

We study the influence of diffusion on NMR experiments when the molecules undergo random motion under the influence of a force field, and place special emphasis on parabolic (Hookean) potentials. To this end, the problem is studied using…

Medical Physics · Physics 2016-05-11 Cem Yolcu , Muhammet Memiç , Kadir Şimşek , Carl-Fredrik Westin , Evren Özarslan

Using a novel NMR scheme we observed persistence in 1-D gas diffusion. Analytical approximations and numerical simulations have indicated that for an initially random array of spins undergoing diffusion, the probability p(t) that the…

Atomic Physics · Physics 2009-11-06 Glenn P. Wong , Ross W. Mair , Ronald L. Walsworth , David G. Cory

We introduce a technique for extracting microstructural geometry from NMR lineshape analysis in porous materials at angstrom-scale resolution with the use of weak magnetic field gradients. Diverging from the generally held view of FID…

Materials Science · Physics 2024-10-15 Mohamad Niknam , Louis-S. Bouchard

Selected theoretical developments in modeling of deposition of submicrometer size (submicron) particles on solid surfaces, with and without surface diffusion, of interest in colloid, polymer, and certain biological systems, are surveyed. We…

Materials Science · Physics 2008-10-16 Vladimir Privman

The diffusion motion of spin-bearing molecules is considerably affected in confined environments. In Nuclear Magnetic Resonance (NMR) experiments, under the presence of magnetic field gradients, this movement can be encoded in spin phase…

Statistical Mechanics · Physics 2022-07-19 Felipe Pereira-Alves , Diogo O. Soares-Pinto , Fernando F. Paiva

The physics of diffusion phenomena in nano and micro channels has attracted a lot of attention in recent years, due to its close connection with many technological, medical and industrial applications. In the present paper we employ a…

Soft Condensed Matter · Physics 2015-09-30 Umberto Marini Bettolo Marconi , Paolo Malgaretti , Ignacio Pagonabarraga

The diffusion of particles trapped in long narrow channels occurs predominantly in one dimension. Here, molecular dynamics simulation is used to study the inertial dynamics of two-dimensional hard disks, confined to long, narrow,…

Soft Condensed Matter · Physics 2020-02-05 Mahdi Zarif , Richard K. Bowles

Magnetic resonance microscopy images at cellular resolution (< 10 microns) are limited by diffusion. SNR and spatial resolution suffer from the dephasing of transverse magnetization caused by diffusion of spins in strong gradients. Such…

The theoretical description of transport in a wide class of novel materials is based upon quantum percolation and related random resistor network (RRN) models. We examine the localization properties of electronic states of diverse…

Strongly Correlated Electrons · Physics 2009-11-13 Gerald Schubert , Holger Fehske

Diffusion is a prominent source of noise affecting nuclear magnetic resonance at the nanometer scale (nano-NMR), preventing high resolution studies of unpolarized liquid samples. Actively managing diffusion noise through, for example,…

Quantum Physics · Physics 2025-02-20 Santiago Oviedo Casado , Daniel Cohen , Javier Cerrillo

Diffusions are a successful technique to sample from high-dimensional distributions. The target distribution can be either explicitly given or learnt from a collection of samples. They implement a diffusion process whose endpoint is a…

Machine Learning · Computer Science 2025-09-03 Andrea Montanari

Lateral diffusion of molecules on surfaces plays a very important role in various biological processes, including lipid transport across the cell membrane, synaptic transmission and other phenomena such as exo- and endocytosis, signal…

Analysis of PDEs · Mathematics 2013-11-12 A. B. Duncan , C. M. Elliott , G. A. Pavliotis , A. M. Stuart

We study the evolution of a wave packet in a nonlinear Schr\"odinger lattice equation subject to a dc bias. In the absence of nonlinearity all normal modes are spatially localized giving rise to a Stark ladder with an equidistant eigenvalue…

Statistical Mechanics · Physics 2010-01-29 Dmitry O. Krimer , Ramaz Khomeriki , Sergej Flach

Nuclear resonant x-ray diffraction in grazing incidence geometry is used to determine the lateral magnetic configuration in a one-dimensional lattice of ferromagnetic nanostripes. During magnetic reversal, strong nuclear superstructure…

Diffusion has been widely used to describe a random walk of particles or waves, and it requires only one parameter -- the diffusion constant. For waves, however, diffusion is an approximation that disregards the possibility of interference.…

Optics · Physics 2014-01-23 Alexey G. Yamilov , Raktim Sarma , Brandon Redding , Ben Payne , Heeso Noh , Hui Cao

Transverse NMR relaxation in a macroscopic sample is shown to be extremely sensitive to the structure of mesoscopic magnetic susceptibility variations. Such a sensitivity is proposed as a novel kind of contrast in the NMR measurements. For…

Soft Condensed Matter · Physics 2007-05-23 Valerij G. Kiselev , Dmitry S. Novikov
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