A full-vectorial integral equation method is presented for calculating near fields and far fields generated by sources in the presence of general finite-sized dielectric structures with cylindrical symmetry. The method is relevant for modeling of a class of antenna designs and some optical components with cylindrical symmetry, e.g., vertical-cavity surface-emitting lasers, microdisk lasers, and light-emitting diodes.
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http://dx.doi.org/10.1364/ol.26.001705 | DOI Listing |
Soft Matter
January 2025
Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
We report an experimental study on how topological defects induced by cylindrical air inclusions in the ferroelectric nematic liquid crystal RM734 are influenced by ionic doping, including an ionic surfactant and ionic polymer. Our results show that subtle differences in molecular structure can lead to distinct surface alignments and topological defects. The ionic surfactant induces a planar alignment, with two -1/2 line defects adhering to the cylindrical bubble surface.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Out of Equilibrium Group, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India.
In biological systems such as cells, the macromolecules, which are anisotropic particles, diffuse in a crowded medium. In the present work, we have studied the diffusion of spheroidal particles diffusing between cylindrical obstacles by varying the density of the obstacles as well as the spheroidal particles. Analytical calculation of the free energy showed that the orientational vector of a single oblate particle will be aligned perpendicular, and a prolate particle will be aligned parallel to the symmetry axis of the cylindrical obstacles in equilibrium.
View Article and Find Full Text PDFInt J Hyperthermia
December 2024
Department of Electrical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
The axis-symmetric modeling technique is based on expanding vector fields in cylindrical harmonics and computing the response on a two-dimensional cross-section separately for each azimuthal harmonic, significantly reducing computational costs. However, it has limitations when dealing with dipoles placed away from the symmetry axis due to challenges in the expansion of angular modes. To address this, we propose a reformulated axis-symmetric model based on the Fourier expansion of the delta function distribution concerning the azimuthal variable.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 2024
Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA 19104.
In this work, the phenomenon of strain induced by a mismatch in thermal expansion coefficients between a thin film and its substrate is harnessed in a new context, replacing the canonical planar support with a three-dimensional (3-D), nanoconfining scaffold in which we embed a material of interest. In this manner, we demonstrate a general approach to exert a continuously tunable, triaxial, tensile strain, defying the Poisson ratio of the embedded material and achieving the exotic condition of "negative pressure." This approach is hypothetically generalizable to materials of low modulus and high thermal expansion coefficient, and we use it here to achieve negative pressure in perovskite-phase CsPbI embedded within the cylindrical pores of anodic aluminum oxide membranes.
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