Search Results (10,586)

To improve the foamability and steam-chest molding performance of polypropylene (PP) bead foams, ethylene-propylene rubber (EPR) was introduced into PP via melt blending. The role of EPR in the complete bead-foaming-to-molding process was systematically investigated by correlating phase morphology, crystallization behavior, melt viscoelasticity, CO₂ dissolution and diffusion, cellular structure, inter-bead welding, and the mechanical properties of molded foam products. The incorporation of EPR refined the PP crystalline morphology, reduced the apparent crystallinity, and markedly enhanced the melt viscoelasticity, thereby broadening the foaming temperature window. The dispersed EPR phase functioned simultaneously as a CO₂ reservoir and a high-diffusivity pathway of CO₂, which promoted cell growth while suppressing excessive nucleation. The enhanced melt viscoelasticity and improved CO₂ affinity promoted bead expansion and optimized the cellular structure. At 150 °C, the expansion ratio increased from 18.7 for neat PP to 21.1 with 10 wt% EPR. EPR also regulated the cellular structure. At 150 °C, the cell diameter increased from 83 to 176 μm as the EPR content increased from 0 to 20 wt%. EPR markedly changed the double-melting behavior of PP bead foams. The low-temperature melting enthalpy increased from 28.5 J/g for neat PP to 37.8 J/g with 10 wt% EPR, which served as an effective interfacial binder, significantly promoting inter-bead welding. Consequently, the optimized PP/EPR foam containing 10 wt% EPR exhibited a tensile strength of 1.13 MPa and an elongation at break of 22.1%. More importantly, excellent molding quality was achieved at a reduced steam pressure of 2.2 bar, demonstrating the great potential of PP/EPR bead foams for the energy-efficient manufacturing of high-performance lightweight products. Full article

The Asian corn borer, Ostrinia furnacalis, is a major pest in China and across East and Southeast Asia, serving as the primary target of Bt maize expressing Cry proteins. Evolution of resistance to Bt toxins represents a critical challenge in plant protection. The high-dose/refuge strategy is more effective when resistance is recessively inherited and fitness costs are present. Here, we characterize the inheritance pattern and fitness costs of Cry1Ab resistance in O. furnacalis using a resistant strain exhibiting a resistance ratio of >1400-fold. The LC₅₀ values of F₁ hybrids from reciprocal crosses between resistant and susceptible strains were 2.44 (1.90–3.12) μg/g and 2.01 (1.53–2.61) μg/g, respectively, with no significant difference, indicating autosomal inheritance. The effective dominance (h) of F₁ offspring decreased with increasing concentration, suggesting that resistance was concentration-dependent. Analysis of observed versus expected mortality in backcross progeny (F₁ × resistant strain) indicated that Cry1Ab resistance is likely governed by more than one genetic locus. Compared with the susceptible strain, resistant individuals exhibited prolonged larval development (18.6 d vs. 17.2 d, p < 0.001), reduced pupation (42.5% vs. 60.8%, p < 0.001) and adult emergence rates (60.3% vs. 87.8%, p < 0.001), while fecundity was not significantly affected. These results verify the existence of fitness costs associated with Bt resistance. Our findings provide important insights into the mechanistic basis of Cry1Ab resistance and will assist in designing proactive management strategies to delay resistance evolution in field populations of O. furnacalis. Full article

Comprehensive biological and ecological data are essential for the appropriate stock management of Solenocera alticarinata Kubo, 1949. The lack of ecological knowledge on S. alticarinata, a species of potential economic value in the East China Sea, limits the development and implementation of appropriate fishery management measures such as minimum landing size and seasonal closure. Accordingly, we employed research vessels to characterize the seasonal spatial distribution patterns of S. alticarinata within the study area (26.5–35° N, 120–127° E) in 2018–2019. Our findings indicate that S. alticarinata can survive at a depth of 50–120 m and sea bottom salinity of 33–35. The highest biomass-based CPUE and greatest abundance of S. alticarinata were found during the summer and autumn, respectively. The seasonal ranking of the total catch per unit effort in number was as follows: autumn (1438.7 ind·h⁻¹) > summer and winter (1012.1–1078.2 ind·h⁻¹) > spring (287 ind·h⁻¹). In terms of mean average individual size, the order was summer > spring > autumn and winter. Overall, our findings provide a basis for developing management policies, and offer insights for designing fishery management and conservation strategies. Full article

This study investigates an IPS-type Metglas/PMN-PT laminated magnetoelectric composite and its feasibility as a reciprocal mechanical magnetoelectric antenna for low-frequency transmission and reception. Finite-element simulations under quasi-static and frequency-domain conditions reveal strong magnetoelectric coupling under an optimal DC bias field, with both the direct magnetoelectric effect (DME) and converse magnetoelectric effect (CME) exhibiting pronounced resonance near 14.5 kHz, governed by the same longitudinal extensional vibration mode. Five IPS samples were fabricated and experimentally characterized. All devices showed resonant frequencies within 14.1–14.5 kHz, peak DME coefficients of 3.0 × 10⁶ to 3.9 × 10⁶ pC/Oe, and peak CME coefficients of 12.0~15.8 Oe·cm/V, confirming good fabrication consistency, transmit–receive reciprocity, and array-integration potential. The parallel IPS antenna generated a magnetic flux density of 37 nT at 1 m, and exhibited an equivalent magnetic noise of 63 fT/Hz^1/2 at 14.45 kHz. These results demonstrate that the proposed IPS structure combines high-sensitivity reception with efficient low-frequency transmission, showing strong potential for miniaturized, low-power, and long-range magnetic communication and underwater communication applications. Full article

Free amino acids (FAAs) are important low-molecular-weight metabolites involved in osmotic regulation, acid–base balance, and nitrogen metabolism in fish exposed to saline–alkaline environments. To characterize tissue-specific FAA responses in mandarin fish (Siniperca chuatsi), 10 cm juveniles were exposed for 96 h to freshwater control (FW), salinity stress (S, salinity 8), alkalinity stress (A, alkalinity 20 mmol/L), or combined saline–alkaline stress (SA, salinity 8 + alkalinity 20 mmol/L). The contents of 19 FAAs were compared among plasma, muscle, liver, brain, and kidney. FAA profiles showed clear tissue specificity. Total FAA (17) decreased in plasma under all stress treatments, increased in muscle under S and SA but decreased under A, increased in liver and kidney, and decreased under single stress but increased under combined stress in brain. Distinct tissue distribution patterns were observed for functional FAA groups. Under salinity stress, osmoregulation-related FAAs, particularly Ala and Pro, showed higher contents mainly in muscle, liver, and kidney. Under alkalinity stress, kidney showed concurrent increases in multiple FAAs, including Ala, Pro, Glu, Gln, Val, Ile, and Leu, whereas brain was characterized by a high Gln content. Under combined saline–alkaline stress, liver was the main tissue in which multiple functional FAA groups increased simultaneously, kidney maintained elevated levels of several FAAs, and brain showed treatment-specific high levels of Gln and Tau. Redundancy analysis (RDA) indicated weak constrained explanatory power of salinity and alkalinity for the overall FAA profile, whereas tissue-specific differentiation was evident. Glu, Gln, and Pro showed directional consistency with the salinity vector, whereas Val and Leu tended to align with the alkalinity-related ordination direction. Overall, acute saline–alkaline exposure induced a functional and tissue-specific distribution pattern of FAAs rather than a uniform whole-body shift in mandarin fish. Full article

The subtropical and tropical islands of East Asia host a unique and highly endemic aquatic insect fauna threatened by a variety of anthropogenic stressors (e.g., invasive species, habitat fragmentation, pollution, and climate change). This review synthesizes the impacts of these stressors on aquatic insect diversity across this region based on 206 articles published over the past 40 years (1985–2025) to evaluate the impacts of these stressors on insular aquatic insect diversity. The islands of East Asia include all or parts of China, Japan, Taiwan, and South Korea. The annual number of publications demonstrates a steady upward trend over time and has been accelerating in the last decade. Our systematic analysis reveals a large geographic disparity. Research is heavily concentrated on major islands, with Honshu Island (42%) and Taiwan Island (24%) accounting for two-thirds of the total literature, while small islands (<10,000 km²) comprise only 20%. Furthermore, current research tends to focus on independent impacts of single stressors, largely overlooking the complex additive, synergistic, or antagonistic interactions that characterize stressors on these fragile ecosystems. These research gaps, compounded by a lack of long-term monitoring data (i.e., only ~22% of the studies span more than 3 years), hinder efforts to distinguish natural inter-annual variability from anthropogenic shifts. The extinction of cryptic or endemic species may occur before these species are identified and described. In addition, the disentanglement of these interactive impacts on aquatic insect communities in East Asian islands is critical for predicting ecosystem responses to further local and global changes. Identification of non-linear ecological tipping points through these long-term monitoring networks, coupled with proactive, science-guided habitat restoration, is essential to mitigate imminent extinctions and to rebuild the functional integrity of these imperiled freshwater ecosystems. Full article

With the increasing complexity of unmanned aerial vehicle (UAV) missions in complex obstacle environments, cooperative hunting of maneuvering ground targets by UAV swarms has become an important problem for multi-agent autonomous decision-making. This paper focuses on a simulated three-UAV hunting scenario in a two-dimensional obstructed environment, where UAVs must search for, approach, encircle, and continuously track a target while avoiding static obstacles under local observation. To address the problem of multi-UAV cooperative hunting of dynamic targets in complex obstacle environments, this paper proposes a curriculum learning (CL)-based Multi-Agent Proximal Policy Optimization algorithm, termed CL-MAPPO. Specifically, a three-stage progressive training curriculum is designed to overcome the challenges of low exploration efficiency, slow environmental adaptation, and difficult convergence of cooperative hunting policies faced by multi-agent deep reinforcement learning in hunting tasks, thereby gradually enhancing the cooperative hunting capability of UAVs in complex environments. Curriculum I employs fixed obstacles and a stationary target position to train the UAVs’ basic obstacle avoidance and target search abilities. Curriculum II introduces randomly generated obstacles and target positions to improve the UAVs’ adaptability to varying environments. Curriculum III further incorporates a dynamic target, prompting the UAVs to learn effective hunting strategies against maneuvering targets. The simulation experiment includes ablation experiments against MAPPO without curriculum learning and comparative simulations against MADDPG and MADQN, using reward convergence curves and trajectory visualizations to evaluate the training results. The results show that, under the same training episodes in the ablation experiment, CL-MAPPO reaches a higher and more stable reward level than vanilla MAPPO, indicating improved learning efficiency without increasing model complexity. In the comparative experiment, the CL-MAPPO algorithm achieved a higher success rate in cooperative hunting. These simulation experiments verify the effectiveness and superiority of the CL-MAPPO algorithm in multi-agent cooperative hunting tasks. Full article

Spatially explicit water-quality information is critical for precision management in pond aquaculture but point sampling alone cannot capture pond-to-pond heterogeneity in multi-unit farms. This single-date, single-farm study re-evaluated the potential of UAV hyperspectral imagery for water-quality screening in inland aquaculture ponds in Shanghai, China, using site-matched extraction from a 138-band orthomosaic (450–998 nm, Cubert S185) acquired during a single UAV survey on 24 August 2023 and matched with 23 GPS-registered sampling sites. Eight water-quality parameters were analyzed: chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), ammonium (${\mathrm{NH}}_4^{+}$ ), nitrite (${\mathrm{NO}}_2^{-}$), nephelometric turbidity unit (NTU), chlorophyll-a (Chla), and total suspended solids (TSS). Raw single-band correlations were modest ($\left|\mathrm{r}\right|$= 0.236–0.417), but two-band difference spectral indices (DSI), normalized spectral indices (NSI), and ratio spectral indices (RSI) substantially improved sensitivity, with $\left|\mathrm{r}\right|$ reaching 0.558–0.928. Quadratic inversion models were calibrated on the full dataset and assessed using three validation layers: two-fold cross-validation, nested leave-one-pond-out (LOPO) validation with within-fold predictor reselection, and extraction-window sensitivity tests. Bootstrap 95% confidence intervals for calibration (Cal) R² characterize small-sample uncertainty (n = 23). Three parameters satisfied all three defensibility criteria (Cal R² > 0.5, CV R² > 0.2, and LOPO R² > 0.2): ${\mathrm{NH}}_4^{+}$ (Cal R² = 0.836 [0.61, 0.94]; LOPO R² = 0.420), COD (0.607 [0.34, 0.82]; 0.328), and NTU (0.862 [0.77, 0.96]; 0.204). TP, TN, ${\mathrm{NO}}_2^{-}$, TSS, and Chla showed overfit behavior under nested holdout and were demoted to exploratory products. A TreeSHAP analysis confirmed that band-to-band contrast carried more explanatory power than raw reflectance magnitude. Extraction-sensitivity tests further demonstrated that positional uncertainty (±2-pixel offset: ΔCV $R^2$= 0.23–0.41) exceeded averaging-window sensitivity (3 × 3→10 × 10: ΔCV $R^2$ ≤ 0.11), identifying geolocation control as the dominant robustness constraint. This single-date, single-farm reanalysis suggests that UAV hyperspectral imagery may support exploratory pond-scale screening of ${\mathrm{NH}}_4^{+}$, COD, and NTU. However, robust quantitative inversion and broader transferability remain unverified and will require denser sampling, improved geolocation control, pond-edge masking, multi-site observations, and multi-temporal calibration. Full article

This study examines how German textbooks provide learning-behavioral affordances for sustainability-oriented intercultural competence development. Drawing on Klieme’s competence-model logic, ESD, intercultural competence research, learning behavior theory, and affordance theory, it treats “sustainable intercultural competence” not as a standardized construct but as a working shorthand for the sustainability-oriented development of intercultural competence. Methodologically, the study adopts a directed qualitative content analysis supplemented by descriptive frequency aggregation. All 37 units across the four volumes of Meilenstein were coded on a 0–2 scale across three affordance dimensions: cognitive-understanding affordance, reflective value-judgment affordance, and interaction-action affordance. The findings show that the series provides substantial but uneven affordances. Interaction-action received the highest aggregated score, followed by cognitive-understanding, whereas reflective value-judgment remained substantially lower. Units on family, identity, sustainability, and civic engagement offer the most balanced affordance structures, whereas everyday practical units privilege communicative action and disciplinary units privilege cognitive understanding. The study argues that textbook-based intercultural learning should be examined not only through topic inclusion but also through how texts, prompts, and tasks organize opportunities for comparison, reflection, judgment, negotiation, and action. Full article

The past few years has witnessed the rapid development of China’s logistics industry. However, the industry still faces problems such as uneven regional development, low-cost efficiency, insufficient technology application, and pressure for green transformation. To support more effective policy and strategic planning, this study used composite location entropy, spatial autocorrelation analysis, and kernel density estimation to analyze the spatiotemporal evolution of logistics industry agglomeration based on China’s city-level panel data from 2010 to 2023. Geographic detectors and geographically weighted regression were used to explore its driving mechanisms from multiple perspectives. The results indicated that (1) China’s logistics industry agglomeration exhibited a decreasing gradient from east to west and the regional disparities gradually narrowed down over time. (2) China’s logistics industry showed significantly positive spatial autocorrelation, characterized mainly by high-high and low-low clusters. Northeastern China experienced the most active and tortuous local spatial evolution of logistics agglomeration, while Eastern China exhibited high tortuosity but stable spatial structure. Western China showed a smooth evolution, and Central China followed a relatively independent evolutionary path. Spatially, China’s logistics industry presented a pattern of high concentration in the southeast and sparse distribution in the northwest, with high-value zones expanding toward the central and western regions. (3) Transportation accessibility was the primary factor influencing logistics industry agglomeration, and the interaction among factors was stronger than the effect of individual factors. Specifically, the degree of openness exhibited a driving pattern centered on coastal areas and decreasing towards inland regions; the level of commercial development showed a positive correlation in the west and a negative correlation in the east; the spatial pattern of transportation capacity shifted from a pronounced east–west polarization to a more fragmented multi-cluster distribution; and transportation accessibility demonstrated spatial heterogeneity, with positive correlation in the southeast coastal areas and negative correlation in the west. Full article

Point clouds acquired by low-cost laser scanning systems have a problem of high noise, which makes the point cloud appear as thick and geometric features blurred, while existing denoising algorithms either fail to maintain a balance between denoising and shape preservation or incur excessive computational cost. To address this issue, this paper proposes a shape-preserving denoising algorithm based on normal-guided cylindrical neighborhood and bilateral weighting. Specifically, the proposed method first optimizes the PCA-initialized normals of the point cloud by integrating curvature-based feature detection and bilateral weighting. Subsequently, a cylindrical neighborhood is constructed for each point along the optimized normal direction. Finally, a bilateral weighted projection mechanism that jointly incorporates spatial and normal features is employed, whereby the aggregated projection of neighboring points drives the displacement of the central point along the normal direction, thereby achieving point cloud denoising. Experiments are conducted on synthetic datasets and real scanned datasets. The results show that, for synthetic data denoising, the proposed method achieves the best or second-best performance in 25 out of 30 experiment cases across different models and different noise levels. For real scanned data, the section views and reconstructed mesh models demonstrate that the proposed method outperforms popular algorithms in removing complex noise while preserving geometric features. In addition, the proposed method demonstrates excellent computational efficiency, capable of denoising at a speed of processing one million points every 2.4 s, and achieves acceleration of processing speed by six times compared to the fastest competitive algorithms. Full article

Mass–balance discrepancies exist between estimated land-based inputs and observed marine plastic inventories. While current global mass–balance models predominantly treat the open ocean as a passive terminal sink, they overlook the rapid expansion of offshore and deep-sea industrial frontiers. This review identifies offshore and deep-sea activities as active, in situ emission nodes of microplastics (MPs). Through a bibliometric analysis and numerical descriptions of studies, we document that direct offshore emissions are underrepresented in the current literature. By synthesizing these limited quantitative data, preliminary metrics indicate localized MP enrichment signals and elevated biological exposure near specific offshore infrastructures. Furthermore, plastics released directly into the marine environment bypass terrestrial weathering, undergoing distinct multiscale aging pathways governed by the complex interplay of wave-induced physical fragmentation bounded by critical size thresholds, UV-driven chemical photo-oxidation, and biological interactions. We conclude that refining global plastic budgets supports moving toward an integrated ocean-industrial framework. However, the synthesis remains constrained by data scarcity and high methodological heterogeneity across different environmental matrices. Future strategies must prioritize standardized in situ flux quantification and the incorporation of MP emission risks into offshore Environmental Impact Assessments. Full article

The Manila clam (Ruditapes philippinarum) is an economically important bivalve widely cultured in coastal aquaculture systems of China. However, the genome-wide genetic background and germplasm differentiation of geographically distinct populations remain unclear, which constrains germplasm conservation and the development of selective breeding programs. In this study, 50 individuals from five representative coastal populations (QZ, ZZ, ZP, CL, and NH) in China were subjected to whole-genome resequencing, producing 126.67 Gb of clean data and 92,593,087 SNPs after stringent filtering. Genetic diversity analyses showed that nucleotide diversity (π) ranged from 0.2453 to 0.2588, observed heterozygosity (Ho) from 0.1316 to 0.1492, and expected heterozygosity (He) from 0.2303 to 0.2435, with the CL population exhibiting relatively lower diversity. Population differentiation was low to moderate, with pairwise F_ST values ranging from 0.0454 to 0.0557. Principal component analysis, neighbor-joining phylogenetic analysis, and Admixture clustering consistently indicated limited population structure and extensive genetic admixture. TreeMix analysis further revealed directional gene flow among populations. Rapid linkage disequilibrium decay and predominantly positive Tajima’s D values suggested relatively stable demographic histories. Despite low genome-wide differentiation, combined F_ST and nucleotide diversity ratio analyses identified localized selective sweep signals in specific genomic regions. These results provide preliminary genome-wide insights into genetic diversity, population connectivity, and candidate localized differentiation signals in R. philippinarum. Given the low sequencing depth, the findings should be interpreted as population-level observations that require further validation using higher-depth genomic datasets before being applied to germplasm conservation and selective breeding programs. Full article

The sluggish kinetics of alkaline hydrogen oxidation reaction (HOR) and high cost of Pt–based catalysts have long hindered large–scale deployment of alkaline membrane fuel cells. Via first–principles calculations, we designed a series of 3d transition metal single atoms anchored on PdN₂ monolayer (TM–PdN₂, TM = Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) and evaluated their alkaline HOR performance. Ti-, Cr-, Fe-, Co-, Ni-modified systems exhibit excellent thermodynamic and electrochemical stability under operating conditions. Single-atom doping tunes the p-band center of N and d-band center of metal sites, enabling precise modulation of H and OH adsorption strengths. Mechanistic analysis reveals HOR follows H₂ + 2OH* → H* + OH* + H₂O → 2H₂O, with the final step as rate-determining step. H adsorption contributes 3.45 times more to HOR activity than OH adsorption. Fe–PdN₂ delivers the best performance, with an ultra–low barrier of 0.11 eV and a rate constant of 2.82 × 10¹⁰ s^–1·site⁻¹, values that significantly outperform those of Pt(111) (0.22 eV, 4.5 × 10⁹ s⁻¹·site⁻¹). This work provides theoretical guidance for rational design of high–performance alkaline HOR electrocatalysts. Full article

Previous research has primarily focused on the restorative effects of environments on the general population, often overlooking the specific restorative capacity of urban settings for the disabled population. There is a lack of comprehensive investigation into the interaction between accessibility elements and urban restorativeness. This study, conducted in Shenzhen, Guangdong Province, China, categorizes streetscape accessibility elements for the disabled population and develops a recognition system based on an enhanced DeeplabV3+ framework. Semantic segmentation of streetscape accessibility elements was performed using 201,860 sampling points and 807,440 street view images. This study employed a combination of TrueSkill scoring, sentiment semantic analysis, LDA topic modeling, and LAB color clustering to quantify and visualize urban restorativeness. The impact of accessibility elements on urban restorativeness was explored using the XGBoost-SHAP model. Results indicate significant effects of architectural space constraints and high-density motor vehicle distribution on the safety of the disabled population’s mobility. The low pixel ratio of accessibility facilities and signs indicates insufficient infrastructure, while high landscape recognition rates exhibit significant spatial coverage heterogeneity. Detection rates for the disabled population in street views are nearly zero, highlighting a severe lack of inclusivity in pedestrian environments. Urban restorativeness exhibited a pattern of being higher in the south and east, and lower in the north and west. Among the accessibility elements, public green spaces (PGS) contributed the most to urban restorativeness, accounting for 25% of the impact, and the study elucidates the mechanisms through which various elements affect urban restorativeness. This absence stems from spatial competition, missing co-design, threshold effect conflicts, and color interference mechanisms. This research breaks away from traditional linear analytical frameworks and reveals the complex non-linear relationship between accessibility elements and urban restorativeness through the XGBoost-SHAP model, providing a quantitative decision-making tool for planning accessible environments in high-density cities. Full article