A mean field model is presented for the configuration dependent effective demagnetizing and anisotropy fields in assemblies of exchange decoupled magnetic particles of arbitrary shape which are expressed in terms of the demagnetizing factors of the particles and the volumetric shape containing the assembly. Perpendicularly magnetized two-dimensional (2D) assemblies have been considered, for which it is shown that the demagnetizing field is lower than the continuous thin film. As an example of these 2D systems, arrays of bistable cylindrical nanowires have been characterized by remanence curves as well as ferromagnetic resonance, serving to show the correspondence of these measurements with the model and also to validate the mean field approach. Linear chains of cylinders and spheres have been analyzed, leading to simple expressions to describe the easy axis rotation induced by the interaction field in chains of low aspect ratio cylindrical particles, and the dipolar magnetic anisotropy observed in the linear chain of spheres. These examples serve to underline the dependence on the dipolar interaction field and effective demagnetizing factor of the contributions that arise from the shape of the outer volume.
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http://dx.doi.org/10.1088/0953-8984/25/22/226003 | DOI Listing |
J Neural Eng
January 2025
Weldon School of Biomedical Engineering, Purdue University, 723 W. Michigan St., Indianapolis, Indiana, 46202, UNITED STATES.
Objective: Direct electrical neurostimulation using continuous sinusoidal low frequency alternating currents (LFAC) is an emerging modality for neuromodulation. As opposed to the traditional rectangular pulse stimulation, there is limited background on the characteristics of peripheral nerves responses to sinusoidal LFAC stimulation; especially within the low frequency range (<50Hz). In this study, we demonstrate LFAC activation as a means to activate motor nerves by direct bipolar nerve stimulation via cuff electrodes, and characterize the factors of activation.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
Solvent environment may significantly affect the equilibria involving flexible solute species, such as proteins and polymers. In the present work, a computation scheme is formulated for the change in the excess chemical potential of a flexible solute molecule upon variation of the solvent condition. The formulation adopts the scheme of error minimization in parallel to the method of Bennett acceptance ratio, and an exact expression is presented that provides the change in the excess chemical potential from solvation free energies computed in two solvent conditions of interest.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
Time-resolved spectroscopy is an important tool for probing photochemically induced nonequilibrium dynamics and energy transfer. Herein, a method is developed for the ab initio simulation of vibronic spectra and dynamical processes. This framework utilizes the recently developed nuclear-electronic orbital time-dependent configuration interaction (NEO-TDCI) approach, which treats all electrons and specified nuclei quantum mechanically on the same footing.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
LPHE-MS, Faculty of Science, Mohammed V University in Rabat, Morocco.
This study explores the optoelectronic and photovoltaic potential of acceptor-π-donor (A-π-D) architectures utilizing CSi quantum dots (CSiQDs) through a combination of density functional theory (DFT) and time-dependent DFT (TDDFT). We examined two key structural configurations: C-C and Si-C conformers. In these systems, CSiQDs serve as the acceptor, CHSF as the π-bridge, and 3 × (CHO) as the donor.
View Article and Find Full Text PDFLeaky mode resonance (LMR) and lossy mode resonance (LMR) refer to two different surface waves but are easily confused. Herein, we comprehensively investigated the excitation mechanism and sensing performance of both LMR and LMR with the same prism-film-surrounding platform based on the rigorous transfer matrix method. Both non-absorbing film waveguides, absorbing film waveguides, and gold-cladding film waveguides were analyzed.
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