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Microsphere-assisted super-resolution polarized light microscopy for polarization-sensitive materials
Full text linkPolarization sensitivity is a fundamental phenomenon observed in nature, and its application is vital for advancing scientific discoveries. Here, we present a microsphere-assisted polarized light microscopy method that enables high-quality, label-free super-resolution imaging of polarization-sensitive materials. We investigated the imaging performance of this method using various samples, including colloidal crystals and grating structures. Both simulations and experiments were performed to explore the underlying physical mechanisms driving the enhancement in imaging quality. The results of this work have potential values for the fields of polarized light microscopy and super-resolution imaging
‘In forests of eternal death […] I bring forth from my teeming bosom myriads of flames’: The Origin of Necropolitics and Visions of Resistance in William Blake’s The Marriage of Heaven and Hell and the Continental Prophecies
Full text linkExperimental Demonstrations of High-Accuracy 3D/2D Indoor Visible Light Positioning Using Imaging MIMO Receivers and Artificial Neural Networks
Full text linkThis paper proposes and presents the first experimental demonstration of a high-precision indoor 2D and 3D visible light positioning (VLP) system using an imaging multiple-input multiple-output (MIMO) configuration with supervised artificial neural network (ANN). The proposed system utilizes four distributed transmitters and receivers with four photodiodes and an imaging optics. The experiments are conducted in a typical indoor environment withtransmitter separations of 300 mm and a link distance of 1400 mm. The experimental results show 2D and 3D positioning accuracies of 3.7 mm and 51 mm, respectively. A simulation model is also developed for the VLP systemto verify the experimental results. Further optimization of the VLP system in the simulation platform leads to improved 2D and 3D positioning accuracies of 2 mm and 9.3 mm, respectively. The proposed system can seamlessly convergewith existing lighting infrastructures and is also compatible with the imaging MIMO visible light communication (VLC) system, indicating the potential for practical implementation in integrated communications and positioning application
Optimized Wide-Angle Metamaterial Edge Filters: Enhanced Performance with Multi-Layer Designs and Anti-Reflection Coatings
Full text linkThis study presents a systematic optimization of wide-angle metamaterial long-pass (LP) edge filters based on silicon nanospheres (SiNP). Multi-layered configurations incorporating SiNP-meta-films and anti-reflection coating (ARC) elements not previously considered in the literature are explored to enhance their filter performance in both stop and pass bands. This research has successfully developed an accurate model for the effective refractive index using Kramers–Kronig relations, enabling the use of classical thin-film design software for rapid device performance optimization, which is verified by full-wave numerical software. This systematic optimization has produced highly efficient, near-shift-free long-pass metamaterial filters, evidenced by their high optical density (OD = 2.55) and low spectral shift across a wide angular range (0°–60°). These advancements herald the development of high-efficiency metamaterial optical components suitable for a variety of applications that require a consistent performance across diverse angles of incidence
Enhanced bed shear stress and mixing in the tidal wake of an offshore wind turbine monopile
Full text linkTidal flow past offshore wind farm (OWF) infrastructure generates a turbulent vortex wake. The wake is hypothesised to enhance seabed stress and water column turbulence mixing, and thereby affect seabed mobility, water column stratification, the transport of nutrients and oxygen, and result in ecological impact. We collect novel hydrodynamic data 40 \unit{m} from an OWF monopile over a spring-neap cycle, and use high frequency velocity measurements to quantify turbulence. Outside of the wake we observe a classical depth-limited boundary layer, with strong turbulence production and dissipation forced by tidal shear at the seabed. Inside the wake, turbulence production, dissipation and stress are enhanced throughout the full water column and are maximised in the upper half of the water column, where they correspond to a strong mean velocity deficit. Our results show that the seabed drag coefficient is doubled from , suggesting greater seabed mobility, and the eddy viscosity is increased by an order of magnitude indicating enhanced water column mixing. This research provides some valuable insight as OWFs expand into deeper seasonally stratified waters using both bottom-fixed and floating structures, where the addition of enhanced wake turbulence may have broad impacts as the additional mixing energy is added to regions with low rates of background mixing
Quantifying spatial gradients in coral reef benthic communities using multivariate dispersion
Full text linkTropical coral reefs are dynamic, disturbance-driven ecosystems that are heterogeneous across space and time, partly owing to gradients in cross-scale human impacts and natural environmental factors. Localized management interventions that strive to maintain the long-term persistence and function of coral reefs need to be informed by how and why reef habitats vary. Using the 'multivariate dispersion' metric, a statistical approach to measure ecological community variability, we quantified spatial gradients in coral reef benthic communities around Tutuila Island in American Samoa, central South Pacific. Benthic communities with low, medium and high dispersion each had distinct and consistent underlying benthic community characteristics. Low dispersion sites were consistently characterized by high hard coral cover, medium dispersion sites were generally dominated by crustose coralline algae, while high dispersion sites were dominated by turf and fleshy coralline algae. Variability in hard coral and turf algal cover explained 42% of the underlying variation in benthic community dispersion across sites, while site-level gradients in human impacts and environmental factors did not correlate well with variations in benthic community dispersion. The metric should be further tested on temporal data to determine whether it can summarize complex community changes in response to and following acute disturbance.</p
Decomposition and stoichiometry variation in lithium hydride and lithium deuteride
Full text linkThe decomposition of the lithium hydride isotopologues (6LiH, 6LiD, 7LiH and 7LiD) and their propensity to accommodate non-stoichiometry is predicted using atomistic modelling methods. Significant differences exist between the reaction enthalpies of the isotopologues with respect to the hydrogen isotope, whilst negligible differences exist with respect to the incorporated lithium isotope. The calculated defect concentration identifies the vacancy formation energy for LiH is significantly lower than for LiD at a defined temperature. Further, the temperatures of complete decomposition to lithium metal for LiH and LiD are reported as 959 K and 999 K, respectively, a 40 K difference of potential use in breeder blanket concepts. The predicted decomposition of LiH is in good agreement with the experimentally observed value of 962 K. Defect concentrations at the decomposition temperature for all isotopologues are similar, despite the changes in temperature