18 research outputs found
Electrostatic Steering of Thermal Emission with Active Metasurface Control of Delocalized Modes
We theoretically describe and experimentally demonstrate a
graphene-integrated metasurface structure that enables electrically-tunable
directional control of thermal emission. This device consists of a dielectric
slab that acts as a Fabry-Perot (F-P) resonator supporting long-range
delocalized modes bounded on one side by an electrostatically tunable
metal-graphene metasurface. By varying the Fermi level of the graphene, the
accumulated phase of the F-P mode is shifted, which changes the direction of
absorption and emission at a fixed frequency. We directly measure the
frequency- and angle-dependent emissivity of the thermal emission from a
fabricated device heated to 250. Our results show that electrostatic
control allows the thermal emission at 6.61 m to be continuously steered
over 16, with a peak emissivity maintained above 0.9. We analyze the
dynamic behavior of the thermal emission steerer theoretically using a Fano
interference model, and use the model to design optimized thermal steerer
structures.Comment: 8 pages, 4 figure
Study and optimization of alternative MBEâdeposited metallic precursors for highly efficient kesterite CZTSe:Ge solar cells
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Can Thyroid Hormone Regenerate Damaged Nerves Following Corneal Injury?
The cornea is the most densely innervated tissue on the bodyâs surface. Corneal nerves, derived from the trigeminal ganglion, are crucial for perceiving stimulation from the external environment and maintaining hydration on the eyeâs surface. Unfortunately, corneal nerves can be damaged following injury or corrective surgery (LASIK). Consequently, nerves are slow to regenerate, causing discomfort and risking further eye damage. Due to the immediate need to restore corneal nerves following injury we examine thyroxine (T4), the main hormone secreted by the thyroid gland, because we and others in the field have found T4 enhances the rate of nerve growth into the cornea (innervation) during development. Herein, we examine whether both cell types (trigeminal neurons and corneal cells), or one type exclusively, is capable of responding to T4 by studying gene expression for T4 receptors in these cells. Further, we are testing whether trigeminal neurons can directly respond to T4 when isolated from the embryo and cultured in vitro, which would provide functional evidence that they are capable of responding to T4
Director Opinion on Community Competence: Evidence from Management Organizations of the Rural Community Support Project in South Korea
In Korea, there are very few successful cases of Rural Community Support Project management organizations, including the economic (income) part as well as the community revitalization part and the facility operation management part. To counter these problems, competence diagnostic results can assist in building these management organizations’ competences. Previously, studies have been conducted on the diagnosis of an individual’s competence. This study, however, was conducted to develop a tool for such a diagnosis using survey items derived through literature review and by verifying the adequacy of this content. The surveys were then finalized by further verifying the construction validity and reliability of the questionnaires. The surveys were administered to the chairs and the directors of Rural Experience Recreational Village councils, to develop an organizational diagnostic tool for the competent operational management of rural communities. The diagnostic tool developed by this study can be used as an indicator to determine whether a rural village has the capacity to carry out projects
All-Solid-State Lithium Battery Working without an Additional Separator in a Polymeric Electrolyte
Considering the safety issues of Li ion batteries, an all-solid-state polymer electrolyte has been one of the promising solutions. Achieving a Li ion conductivity of a solid-state electrolyte comparable to that of a liquid electrolyte (>1 mS/cm) is particularly challenging. Even with characteristic ion conductivity, employment of a polyethylene oxide (PEO) solid electrolyte has not been sufficient due to high crystallinity. In this study, hybrid solid electrolyte (HSE) systems have been designed with Li1.3Al0.3Ti0.7(PO4)3 (LATP), PEO and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). A hybrid solid cathode (HSC) is also designed using LATP, PEO and lithium cobalt oxide (LiCoO2, LCO)—lithium manganese oxide (LiMn2O4, LMO). The designed HSE system has 2.0 × 10−4 S/cm (23 °C) and 1.6 × 10−3 S/cm (55 °C) with a 6.0 V electrochemical stability without an additional separator membrane introduction. In these systems, succinonitrile (SN) has been incorporated as a plasticizer to reduce crystallinity of PEO for practical all-solid Li battery system development. The designed HSC/HSE/Li metal cell in this study operates without any leakage and short-circuits even under the broken cell condition. The designed HSC/HSE/Li metal cell in this study displays an initial charge capacity of 82/62 mAh/g (23 °C) and 123.4/102.7 mAh/g (55 °C). The developed system overcomes typical disadvantages of internal resistance induced by Ti ion reduction. This study contributes to a new technology development of all-solid-state Li battery for commercial product design
Design parameters of free-form color splitters for subwavelength pixelated image sensors
Summary: Metasurface-based color splitters are emerging as next-generation optical components for image sensors, replacing classical color filters and microlens arrays. In this work, we report how the design parameters such as the device dimensions and refractive indices of the dielectrics affect the optical efficiency of the color splitters. Also, we report how the design grid resolution parameters affect the optical efficiency and discover that the fabrication of a color splitter is possible even in legacy fabrication facilities with low structure resolutions
EEG Source Localization Analysis for Local-Global Visual Processing Using Sloreta
The aim of this study was to assess whether Standardized Low Resolution Brain Electromagnetic Tomography (sLORETA) can detect differences in EEG source distribution during local and global stimuli cognition process or not. We recorded the cortical brain activity from 40 subjects (M:F=20:20) during local and global stimuli cognition process. The stimuli were generated based on the modified version of Navon's hierarchical structured stimuli [1]. We found the differences in 4-8 Hz theta oscillation during the task between male and female groups in sLORETA patterns, particularly in the right temporal cortex. We also found the similar theta oscillation patterns in power spectrum analysis: higher synchronized theta activity between posterior parietal lobe and frontal lobe was found in female group than that of male group. These findings suggest higher dependence on local-global stimulation cognition and memory recall in female. We suggest that sLORETA can be a good tool for detecting local-global stimulus cognition and be a good diagnostic for the neuropsychiatric disorders related to the local-global processing such as Obsessive-compulsive disorder and Posttraumatic stress disorder