329 research outputs found
Nuovi dati sulla circolazione della ceramica d’importazione islamica e bizantina a Genova: Il contesto di S. Maria delle Grazie La Nuova,
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Ambition before Ethics: A Biography of Banastre Tarleton (1754–1833)
No full textAbout the author
Michael Melli is a senior at The University of Central Florida on the Presidents List finishing his History major and Political Science minor, with concentration on English Monarchical History. His research interests include Victorian and Edwardian royal foreign relations and Georgian military history
Analysis and Assessment of Tube Thickness Variation Effect in Hollow-Core Inhibited Coupling Tube Lattice Fibers
No full textHollow-Core Inhibited Coupling Fibers have been the target of great investigation efforts due to their peculiar properties [1]. These features, in addition to their capability to handle high power levels, make this kind of fibers very attractive for a wide range of applications such as high-power lasing, light-gas interaction, plasma photonics, quantum physics, terahertz systems, and gas- and bio-sensing. The guidance mechanism of Inhibited Coupling (IC) fibers relies on the spatial mismatch between core modes and cladding modes (CLMs). In this way, the coupling between core and CLMs, caused by their spatial overlap, is dramatically reduced [1]. An effective way to strengthen this effect is to deploy hypocycloid core-contour (i.e. negative curvature) fiber designs [2]. A negative curvature core can be simply obtained by fabricating a cladding structure made of a layer of thin isolated glass tubes arranged around the hollow core (Tube Lattice Fibers - TLFs) [3] , [4]. Although TLFs have reached an extremely low transmission loss and are intensely developed [5] , [6] a gap remains between measured transmission and the theoretical minimum given by confinement loss (CL). This difference can be ascribed to geometrical non-idealities of the fiber structure, introduced during the fabrication process, even though a theoretical analysis showing the real reason for this gap is not yet available
La cucina e la mensa della famiglia degli Embriaci. Un contesto archeologico genovese di XII/XIII secolo
No full textNon-idealities in hollow core inhibited coupling fibers
No full textHollow Core Inhibited Coupling Fibers are experiencing an impressive reduction of their propagation loss. Despite that, there is still a difference between experimental loss and the theoretical minimum defined by confinement loss. This difference is assumed to be due to additional losses caused by geometrical irregularities of the real fibers compared to the ideal geometry, due to the fabrication process. In this work, we numerically investigate additional losses coming from several kinds of geometrical imperfections, highlighting their impact in defining fiber total loss
Extending the Applicability of the Semi-experimental Approach by Means of "template Molecule" and "linear Regression" Models on Top of DFT Computations
No full textThe accurate determination of equilibrium structures for isolated molecules plays a central role in the evaluation and interpretation of stereoelectronic, thermodynamic, and spectroscopic properties. For small semi-rigid systems, state-of-the-art quantum-chemical computations can rival the most sophisticated experimental results. For larger molecules, cheaper yet accurate approaches need to be defined. The double-hybrid rev-DSD-PBEP86 functional already delivers remarkable results that can be further improved by means of a "Lego brick"model. This is based on the idea that a molecular system can be seen as formed by different fragments (the "Lego bricks"), whose accurate semi-experimental (SE) equilibrium geometries are available. The template molecule (TM) approach can be used to account for the modifications occurring when going from the isolated fragment to the molecular system under investigation, with the linear regression (LR) model employed to correct the linkage between the different fragments. The resulting TM-SE_LR approach has been tested with respect to available SE equilibrium structures and rotational constants. Indeed, the latter parameters straightforwardly depend on the equilibrium geometry of the system under consideration. The main outcome of our study is the reliability, robustness, and accuracy of this novel approach. The molecular systems considered for benchmarking the TM-SE_LR scheme are those formally issued from addition/elimination reactions of nucleophilic unsaturated radicals (e.g., CN, C2H, and phenyl) to alkenes, imines, and aldehydes, whose rotational spectra have been investigated, but accurate structural determinations are not yet available
Optimizing optical setup for transmission spectra shift-based measurement of DNAs in hollow-core photonic crystal fibers
No full textHollow-core photonic crystal fibers have shown promising potential for label-free DNA detection, relying on a multi-step functionalization of their inner surface to capture target DNA selectively. This process forms a bio-layer altering the fiber's cladding thickness, causing a shift in the transmission spectrum and allowing a label-free detection with just an attenuation measurement. However, it is crucial to ensure the excitation of the fundamental mode (FM) at each functionalization step. The current optical setup has limitations: achieving FM excitation is difficult, and mode verification relies on a camera that averages modes over the range of wavelengths. In this paper, the first issue is addressed by adding two mirrors between the light source and the fiber so that the angle of light entering the fiber can be controlled, avoiding the excitation of the high order modes (HOMs) and making the setup more stable and flexible. The second issue is solved by using the band-pass filters before the camera so that the FM excitation can be checked at specific wavelengths of greater utility for the detection process. The experiments have shown that the mirrors allowed the excitation of a range of different modes, and the filters were found to be useful in improving the sensing accuracy. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved
2D+1 and 3D Simulation Methods for Hollow Core Fibers Non-Idealities Analysis
No full textWe propose three numerical approaches for the analysis of Hollow Core fibers non-idealities along fiber propagation direction. The first two are 2D+1 approaches and relies on the Coupled Mode Theory and the Mode Matching Method. While the third is a full 3D method since it relies on a 3D finite element method simulation
Transverse Roughness Effect on Fundamental Mode Confinement Loss and Modal Content of Hollow-Core Inhibited Coupling Tube Lattice Fibers
No full textThe effects of the transverse surface roughness on fiber loss and modal content in hollow-core inhibited coupling tube lattice fibers is numerically investigated. Relationship between roughness spectrum and loss of core modes is assessed
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