Copper ions (Cu⁺ and Cu²⁺) serve as important luminescent centers in various inorganic materials but often coexist within the same host lattice. Both ions exhibit broadband emissions with analogous peak shapes and closely overlapping peak positions. This spectral similarity, however, makes it extremely challenging to distinguish Cu⁺ and Cu²⁺ from each other via conventional luminescence spectroscopy, which hinders in-depth investigations into their distinct luminescent mechanisms and limits the exploration of their application potential in advanced optical systems. In this work, we address this challenge by actively manipulating the valence states of Cu ions doped in CaAl₂O₄ through selective co-doping with mono-valent Na⁺ and trivalent lanthanide ions (La³⁺/Tb³⁺/Dy³⁺). Combined experimental and first-principles studies reveal that Na⁺ doping effectively stabilizes Cu²⁺, leading to an intense blue emission centered at 471 nm. Conversely, co-doping with trivalent lanthanides promotes the formation of Cu⁺, resulting in a bright green emission peak at 501 nm. Leveraging this valence tunability, we demonstrate a prototype optical encoding device based on their cooperative luminescence, highlighting its promising utility in anti-counterfeiting technologies. This study not only provides a fundamental understanding for deciphering and controlling the luminescence of copper ions with different valencies, but also offers valuable guidance for the design of novel multifunctional Cu-activated phosphors.

Deploying scalable Vision Transformer applications on mobile and edge devices is constrained by limited memory and computational resources. Existing model development and deployment strategies include distributed computing and inference methods such as federated learning, split computing, collaborative inference and edge-cloud offloading mechanisms. While these strategies have deployment advantages, they fail to optimize memory usage and processing efficiency, resulting in increased energy consumption. This paper optimizes energy consumption by introducing adaptive model partitioning mechanisms and dynamic scaling methods for ViTs such as EfficientViT and TinyViT, adjusting model complexity based on the available computational resources and operating conditions. We implement energy-efficient strategies that minimize inter-layer communication for distributed machine learning across edge devices, thereby reducing energy consumption from data flow and computation. Our evaluations on a series of benchmark models show improvements, including up to a 32.6% reduction in latency and 16.6% energy savings, while maintaining mean average precision sacrifices within 2.5 to 4.5% of baseline models. These results show that our proposal is a practical approach for improving edge AI sustainability and efficiency.

HTTP/3 (H3) has experienced significant growth and extensive adoption in various scenarios, especially in Content Delivery Networks (CDNs). Over the past few years, there have been numerous insightful studies on its deployment in industrial CDNs. However, these studies often separately analyze H3 and CDN, overlooking their synergistic integration. In this work, we explore the applicability of H3 in CDN from a holistic perspective. We analyze 325 websites hosted by seven CDN providers and identify three key characteristics where CDN align perfectly with H3's strengths. Firstly, CDN resources dominate the composition of webpages, where enabling H3 can amplify H3's benefits in connection acceleration. Secondly, CDN providers also exhibit a dominant characteristic, with the majority of CDN resources hosted by a few large providers. This phenomenon makes different webpages share the same provider. When browsing consecutively, H3 helps to skip the connection phase by resuming the connections to the same CDN provider across pages. Thirdly, H3 mitigates the congestion problem on webpages serving multiple CDN resources. This work provides a deeper insight into the applicability of H3 in large-scale distributed systems like CDNs, holding promise for informing the development and optimization of industrial H3.

The red afterglow of current rare-earth-activated long persistent luminescence (LPL) phosphors is largely still less than 6 h, in contrast to the 20 or 30 h long blue- or green-emitting ones, becoming the main obstacle to realize their multiscenario applications in practice. Herein, we report a rare-earth-free red-emitting LPL phosphor SrGa₂O₄:Cu²⁺that can exhibit an afterglow at about 622 nm lasting over 30 h, which can largely match with the luminance of current blue- or green-emitting LPL phosphors. We find that the Cu²⁺ion could be charged by ultraviolet light from 280 to 420 nm, and the emission has a very broad band with a full width at half-maximum of about 150 nm. Combining the thermoluminescence measurement and the first-principles calculation, we find that the O vacancies and the -1 charged Ga vacancies could store the holes and contribute to the LPL of SrGa₂O₄:Cu²⁺. Our results may dramatically promote and expand its potential applications and stimulate the research of the multicolor LPL phosphors in future.