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In this work, we introduce DyESP, a novel approach that unites dynamic exploration with space pruning to expedite the combined search of hyperparameters and architecture, enhancing the efficiency and accuracy of hyperparameter-architecture search (HAS). Central to DyESP are two innovative components: a meta-scheduler that customizes the search strategy for varying spaces and a pruner designed to minimize the hyperparameter space by discarding suboptimal configurations. The meta-scheduler leverages historical data to dynamically refine the search direction, targeting the most promising areas while minimizing unnecessary exploration. Meanwhile, the pruner employs a surrogate model, specifically a fine-tuned multilayer perceptron (MLP), to predict and eliminate inferior configurations based on static metrics, thereby streamlining the search and conserving computational resources. The results from the pruner, which identifies and removes underperforming configurations, are fed into the meta-scheduler. This process updates the historical dataset used by the meta-scheduler, enabling it to adjust the exploration degree and refine the sampling strategy for subsequent iterations. This integration ensures the meta-scheduler is continually updated with relevant data, allowing for more accurate and timely adjustments to the exploration strategy.Experiments on various benchmarks show that DyESP outperforms existing methods in terms of both speed and stability on almost all benchmarks. 

ABSTRACT The Earth's ionosphere plays a critical role in radio wave transmission, reflection, and scattering, directly affecting communication, navigation, and positioning systems. However, the comprehensive impacts of space weather remain to be fully established in cases where the ionosphere experiences strong disturbances during geomagnetic storms. We reported unprecedented observational evidence of extreme ionospheric electron density depletion and its hemispheric asymmetry during the May 10–12, 2024 super geomagnetic storm, utilizing multi-instrument ground-based and spaceborne in-situ observations. The ionospheric electron density significantly decreased, with a maximum reduction of 98% over the whole northern hemisphere for more than 2 days, causing backscatter echo failures in multiple ionosondes within the Chinese Meridian Project (CMP) monitoring network. In contrast, mid-to-low latitude regions in the southern hemisphere exhibited electron density enhancements. Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM) simulations demonstrated strong consistency with northern hemispheric observations. The vertical drift and the column integrated ratio of O and N2 (ΣO/N2) from observations and simulations indicated the deep reduction of total electron content (TEC) mainly generated by severe ion recombination associated with neutral composition changes that interacted with the disturbed electric field. The summer to winter neutral wind and asymmetry of O/N₂ were possibly responsible for the asymmetry in electron density between the northern and southern hemispheres. These results advance understanding of ionospheric storm physics by establishing causal links between magnetosphere-thermosphere coupling processes and extreme electron density variations, while providing critical observational constraints for space weather model refinement. 

Herein, this work aims to demonstrate the topological effect on the mechanicalx characteristics of selfassembled block copolymers (BCPs). The lamellae-forming polystyrene- block -polydimethylsiloxane (PSb -PDMS) can be self-assembled into various nanostructured monoliths with the use of PS-selective solvent for solvent annealing, giving diamond, gyroid, and cylinder structures with increasing the swelling degree of PS domain (the effective volume fraction of the PS segment after solvent annealing followed by evaporation). The stiffness of the self-assembled monoliths is scrutinized by nanoindentation test. For intrinsic PS- b -PDMS monolith with lamellar structure, the reduced elastic modulus as calculated from the measured stiffness is 0.91 GPa. By contrast, the PS- b -PDMS monolith with cylinder structure gives a significant reduction in reduced elastic modulus with the value of 0.52 GPa due to the introduced microporosity to the PS domain from solvent annealing using PS-selective solvent, resulting in the lower confrontation for continuous layer-by-layer deformation of hard PS and soft PDMS domains. In the case of gyroid-structured PS- b -PDMS monolith, it is unexpected to exhibit a significant increase in the reduced elastic modulus with a value of 1.6 GPa: note that the effect of microporosity is still significant. Accordingly, the enhancement of the reduced elastic modulus is attributed to the effect of deliberate structuring with network topology ( i.e., three-dimensional co-continuous hard PS and soft PDMS domains) that is able to hold the occurrence of large-scale deformation. In contrast to the gyroid with a three-strut texture, the diamond-structured PS- b -PDMS monolith with a four-strut texture is superior to the gyroid with a reduced elastic modulus of 2.2 GPa, further confirming the suggested topology effect. 

Abstract The Jiamusi (JME) radar is the first high‐frequency coherent scatter radar independently developed in China. In this study, we investigate the statistical characteristics of the Jiamusi radar scattering occurrence rate from the F‐region ionosphere between 40°N and 65°N geomagnetic latitude (MLAT) from March 2018 to November 2019. Then, the diurnal and seasonal variations in scattering echoes and their dependence on geomagnetic conditions are statistically investigated. It is shown that the local time of the peak scattering occurrence rate varies depending on the seasons, that is, approximately 20–22.5 magnetic local time (MLT) in summer, 17.5–20.5 MLT in equinox, and 16–17.5 MLT in winter, which is closely associated with the time of sunset. The occurrence rate also increases with the enhancement of the Kp index. To further understand the mechanism of these features, we simulate the distribution of the gradient drift instability (GDI) indicatorby using the Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (TIEGCM). The analysis results indicate that the GDI may be one of the factors that contribute to these characteristic features.