Federated Domain Generalization (FDG) aims to train models on multiple heterogeneous source domains that generalize to unseen domains without access to target data. Existing methods mainly rely on learning domain-invariant representations while overlooking the transferability of prototypes from source domains to target domains. To address this limitation, we propose FedPRC, a prototype region calibration framework that models cross-domain transformations instead of enforcing strict invariance. FedPRC first uses a fixed prototype classifier to establish a globally shared geometric structure, which maintains consistent class-level representations across clients. Then, we introduce a pseudo-target domain generation module, which constructs virtual features to represent unseen domains and capture cross-domain variability, enabling semantic calibration. Finally, we design a prototype region calibration (PRC) module, which promotes a uniform distribution of intra-class features while preserving semantic consistency and reduces decision ambiguity on unseen domains, achieving distribution calibration. Extensive experiments on four benchmark datasets (PACS, OfficeCaltech10, Office31, and OfficeHome) involving heterogeneous multi-client settings demonstrate that FedPRC consistently outperformed nine state-of-the-art methods, achieving up to 4.56% improvement in FDG accuracy and 5.02% gain under domain-shift evaluation, while incurring only marginal computational overhead. These results validate the effectiveness and practical scalability of the proposed approach. https://github.com/qqh0618/FedPRC
In this work, nickel-doped ZnIn2S4 (xNi-ZIS) photocatalysts were prepared by a solvothermal method, and their light-driven hydrogen evolution and MO degradation performance were investigated. The optimized 2Ni-ZIS exhibits excellent photocatalytic performance, with a hydrogen evolution rate of up to 20.74 mmol g−1 h−1, more than 8 times that of ZIS. The degradation rate of MO reached 81.8% within 90 min. Further magnetization of the 2Ni-ZIS sample (2Ni-ZIS-Mag) significantly enhances its hydrogen evolution performance to 30.19 mmol g−1 h−1, with an apparent quantum efficiency of 6.74% at 420 nm. The MO degradation rate increases to 97.2%. The experimental results indicate that Ni doping causes a red shift of the absorption edge of ZnIn2S4, markedly improving its visible-light absorption capability. Electron paramagnetic resonance and field cooling demonstrate that Ni doping induces a magnetic moment of 2.83 μB in ZnIn2S4. This is attributed to the optimization of the electron spin configuration in 2Ni-ZIS-Mag. Its carrier lifetime is extended from 25.68 ns to 31.36 ns, and the effective magnetic moment is also increased to 3.47 μB. The induced localized spin-polarized state effectively promotes the separation and migration of photogenerated carriers, thereby prolonging the carrier lifetime. Theoretical analysis further reveals that the excellent photocatalytic performance of Ni-ZIS also originates from the elevated Fermi level and optimized hydrogen evolution free energy. Based on mass spectrometry and the excited-state Fukui function, the possible degradation pathways of the MO molecule were proposed
This paper investigates the prescribed-performance tracking problem of electro-hydraulic servo systems subject to actuator saturation and external disturbances from a fractional-order auxiliary-dynamics perspective. To guarantee both transient and steady-state performance, time-constrained prescribed performance functions are constructed without imposing the conventional initial feasibility condition. However, practical electro-hydraulic servo systems are inevitably subject to actuator saturation because of physical input constraints. Such saturation may drive the tracking error close to or beyond the prescribed bounds, thereby invalidating the prescribed performance transformation and deteriorating transient behavior. To address this issue, a fractional-order auxiliary system is introduced to regulate the prescribed performance bounds under saturation. Owing to its nonlocal memory property, the introduced auxiliary dynamics suppresses excessive bound expansion during repeated saturation. Compared with conventional integer-order auxiliary systems, the proposed approach achieves smoother and less conservative regulation of prescribed performance bounds. Lyapunov analysis establishes semiglobal uniform ultimate boundedness of all closed-loop signals. The tracking error is constrained within the regulated prescribed bounds after the prescribed transient interval, while the fixed-time property is established for the performance-bound evolution. Comparative simulations and experiments on an electro-hydraulic servo platform are carried out. The results demonstrate that the proposed modelling and control scheme improves boundary regulation smoothness and performance recovery under repeated saturation conditions compared with conventional integer-order auxiliary approaches.
Controlling charge carrier dynamics through nanostructural engineering remains a pivotal challenge in advancing photocatalyst performance. In this work, sheet-like BiOBr precursors were synthesized via a hydrothermal method, followed by the construction of unique BiOCl micro rings (CMR) through an ion exchange strategy. Systematic characterizations confirm the CMR’s distinct ring-like morphology. Compared to the sheet-like BiOBr, the CMR exhibits a more negative flat-band potential, a lower work function, significant electron delocalization characteristics, and efficient separation of photogenerated carriers. And that endows the CMR with stronger photocatalytic reduction capability. Theoretical calculations further unlock a transition of the CMR from a direct bandgap to an indirect bandgap. This transition, driven by the reconstruction of carrier recombination centers in reciprocal space, reduces the transition dipole moment and significantly suppresses charge recombination. Photocatalytic evaluations under simulated sunlight demonstrated that the CMR degrades methyl orange at rates 2.1 times and 3.7 times higher than those of pristine BiOCl and BiOBr, respectively. The photocatalytic hydrogen evolution rate of CMR is 3 times that of BiOCl and 5.7 times that of BiOBr, respectively. Furthermore, excited-state computational studies elucidate a multi-path MO degradation mechanism involving concurrent nucleophilic, electrophilic and radical attack. This work provides important insights for designing advanced photocatalyst morphologies and deepens the theoretical understanding of molecular degradation pathways.
Anthocyanins (ACNs) are natural pigments with potent antioxidant activity, but their application in functional foods is restricted by their instability against heat and light. In this study, mung bean porous starch (PS) was prepared via ultrasound-assisted ethanol exchange at different ultrasonic powers and used as a wall material for ACN encapsulation, resulting in the formation of a PS@ACN composite system. The adsorption mechanism and stability enhancement were systematically investigated. The results showed that ultrasonic treatment significantly enhanced the adsorption capacity of PS, with the maximum loading capacity of 4.91 mg·g−1 obtained at 240 W. The suitability of the pseudo-first-order kinetic framework for describing the adsorption behavior suggested a predominantly physical adsorption pathway. Multiscale characterization showed that ultrasonic cavitation increased the specific surface area and pore volume at the macroscopic level. At the microscopic level, ultrasonic treatment disrupted the short-range ordered structure of starch and exposed more hydroxyl groups as potential binding sites. Molecular docking results suggested that hydrogen bonding was the primary driving force for the adsorption. Furthermore, the encapsulation significantly enhanced the stability of ACN, with the retention rate increasing with ultrasonic power. Under extreme thermal treatment (100 °C), the stability of PS@ACN was improved by at least 1.5 times compared to free ACN. In vitro digestion experiments further showed that PS-240@ACN offered superior gastrointestinal protection and intestinal-responsive release. This study suggests that ultrasound-modified PS, especially at 240 W, may serve as a promising protective carrier for ACN.
