NbN films are grown on c-plane sapphire substrates by molecular beam epitaxy. The structural and superconducting properties of the films are characterized to demonstrate that growth parameters such as substrate temper...
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NbN films are grown on c-plane sapphire substrates by molecular beam epitaxy. The structural and superconducting properties of the films are characterized to demonstrate that growth parameters such as substrate temperature and active nitrogen flux affect the structural phase of films, and thereby the superconducting critical temperature. Four phases of NbN are identified for films grown in different conditions. We demonstrate that atomically flat and highly crystalline β−Nb2N films can be grown at substrate temperatures of 1100∘C or higher, and that the superconducting critical temperature of phase-pure β−Nb2N films is 0.35
Contrary to the common belief that the light-induced halide ion segregation in a mixed halide alloy occurs within the illuminated area,we find that the Br ions released by light are expelled from the illuminated area,...
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Contrary to the common belief that the light-induced halide ion segregation in a mixed halide alloy occurs within the illuminated area,we find that the Br ions released by light are expelled from the illuminated area,which generates a macro/mesoscopic size anion ring surrounding the illuminated area,exhibiting a photoluminescence *** intriguing phenomenon can be explained as resulting from two counter-balancing effects:the outward diffusion of the light-induced free Br ions and the Coulombic force between the anion deficit and surplus *** after removing the illumination,the macro/mesoscopic scale ion displacement results in a built-in voltage of about 0.4 V between the ring and the ***,the displaced anions return to the illuminated area,and the restoring force leads to a damped ultra-low-frequency oscillatory ion motion,with a period of about 20-30 h and lasting over 100 *** finding may be the first observation of an ionic plasma oscillation in *** understanding and controlling the"ion segregation"demonstrate that it is possible to turn this commonly viewed"adverse phenomenon"into novel electronic applications,such as ionic patterning,self-destructive memory,and energy storage.
Double-side cooled power modules are being developed for next-generation traction inverters due to their better heat extraction, lower profile, and lower parasitic inductances. However, due to their rigid structure, t...
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The future deployment of terawatt-scale proton exchange membrane water electrolyzer (PEMWE) technology necessitates development of an efficient oxygen evolution catalyst with low cost and long lifetime. Currently, the...
The future deployment of terawatt-scale proton exchange membrane water electrolyzer (PEMWE) technology necessitates development of an efficient oxygen evolution catalyst with low cost and long lifetime. Currently, the stability of the most active iridium (Ir) catalysts is impaired by dissolution, redeposition, detachment, and agglomeration of Ir species. Here we present a ripening-induced embedding strategy that securely embeds the Ir catalyst in a cerium oxide support. Cryogenic electron tomography and all-atom kinetic Monte Carlo simulations reveal that synchronizing the growth rate of the support with the nucleation rate of Ir, regulated by sonication, is pivotal for successful synthesis. A PEMWE using this catalyst achieves a cell voltage of 1.72 volts at a current density of 3 amperes per square centimeter with an Ir loading of just 0.3 milligrams per square centimeter and a voltage degradation rate of 1.33 microvolts per hour, as demonstrated by a 6000-hour accelerated aging test.
Unmanned aerial vehicles (UAVs) are a valuable source of data for a wide range of real-time applications, due to their functionality, availability, adaptability, and maneuverability. Working as mobile sensors, they ca...
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A meta-optic platform for accelerating object classification is demonstrated. End-to-end design is used to co-optimize the optical and digital systems resulting in a high-speed and robust classifier with 93.1% accurac...
In this study, we explore the classification and prediction capabilities of three models-Genetic programming (GP), Logistic Regression (LR), and the Kolmogorov-Arnold Network (KAN)-on the task of sodium-ion battery li...
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We present a dip testing setup, which employs a copper mold instrumented with high resolution distributed fiber-optic sensors, to precisely map closely spaced thermal features that are imparted to the mold during stee...
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A meta-optic platform for accelerating object classification is demonstrated. End-to-end design is used to co-optimize the optical and digital systems resulting in high-speed classifiers that are demonstrated for hand...
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