Search Results (2,948)

The thioether-functionalized 2-azabutadiene (ⁱPrS)₂C=C(H)-N=CPh₂ L1 ligates to Mn(CO)₅Br to form the five-membered chelate compound fac-MnBr(CO)₃[(ⁱPrS)₂C=C(H)-N=CPh₂] MnPropBr, whose crystal structure has been determined from X-ray diffraction data. In the crystal, different secondary intermolecular interactions, such as Br^…HC and π^…π, give rise to a supramolecular network. The electronic properties of the metal–ligand bonds in MnPropBr are similar to those of complex MnPhBr (with R = SPh instead of ⁱPrS); this also applies to a series of structurally analogous fac-ReX(CO)₃[(RS)₂C=C(H)-N=CPh₂] (X = Cl, Br and I; R = SⁱPr, SPh and S^tBu) rhenium complexes and are discussed on the basis of QT-AIM (Quantum Theory of Atoms in Molecules) calculations. New bond length/electron density relationships are proposed for the metal–halide bonds, including, for the first time, complexes of one given metal and all three corresponding halides. In order to obtain a set of coherent data, three manganese complexes that belong to the family fac-MnX(CO)₃[N∩N] (X = Cl, Br and I; N∩N is a chelating ligand with two coordinating N atoms) were included in this study. Full article

In the context of the high development of mobile internet and social media, the social clocking and photographing function of tourism applications has become a key factor to enhance user experience and enhance product competitiveness. Citywalk, as a new way of exploring cities, emphasizes individuality and social interaction by providing a walking experience of the city’s history and culture. This study is based on the Technology Acceptance Model, combined with the Use and Gratification Theory, to systematically explore the core mechanisms that influence user acceptance and continued use of the social check-in and photo-taking function in Citywalk-related applications (app). Firstly, this article analyzes the impact of perceived usefulness and perceived ease of use on user technology adoption through a technology acceptance model. At the same time, the five major needs of use and satisfaction theory (information needs, entertainment needs, social interaction needs, identity confirmation needs, and escapism needs) are introduced as external influencing variables to construct an optimized technology acceptance model. Secondly, based on this theoretical framework, this article proposes relevant research hypotheses and designs a questionnaire for empirical analysis. Reliability analysis, validity analysis, and regression analysis are used to verify the relationship between influencing factors and user behavior. The research results reveal relevant research questions, namely, the core factors influencing users’ use of social check-in and photo-taking functions (RQ1), elucidating the mechanism of technology perception on user satisfaction and willingness to continue using (RQ2), and identifying the acceptance gap between user needs and actual experience in existing feature designs (RQ3). At the same time, this article provides optimization strategies for the Citywalker App (Version 1.0) and similar products to enhance user experience, strengthen social communication effects, and promote market promotion. Ultimately, this study aims to provide theoretical support and practical guidance for the design of tourism social media functions and promote innovative development in related fields. Full article

Graph Neural Networks (GNNs) face significant challenges in node classification across diverse graph structures. Traditional message passing mechanisms often fail to adaptively weight node relationships, thereby limiting performance in both homophilic and heterophilic graph settings. We propose the Eigenvector Distance-Modulated Graph Neural Network (EDM-GNN), which enhances message passing by incorporating spectral information from the graph’s eigenvectors. Our method introduces a novel weighting scheme that modulates information flow based on a combined similarity measure. This measure balances feature-based similarity with structural similarity derived from eigenvector distances. This approach creates a more discriminative aggregation process that adapts to the underlying graph topology. It does not require prior knowledge of homophily characteristics. We implement a hierarchical neighborhood aggregation framework that utilizes these spectral weights across multiple powers of the adjacency matrix. Experimental results on benchmark datasets demonstrate that EDM-GNN achieves competitive performance with state-of-the-art methods across both homophilic and heterophilic settings. Our approach provides a unified solution for node classification problems with strong theoretical foundations in spectral graph theory and significant empirical improvements in classification accuracy. Full article

Background: Stunting remains a major public health issue globally and in Indonesia, often linked to inadequate complementary feeding, cultural practices, and limited family empowerment. Objective: This study aimed to develop and evaluate a family empowerment model based on transcultural care theory to improve quality and prevent stunting among children aged 6–24 months. Methods: A cross-sectional explanatory survey was conducted among 324 mother–child pairs from 11 primary healthcare centers in Kediri, East Java. Data were collected using a validated questionnaire covering demographic, educational, technological, economic, and cultural factors, as well as family empowerment and quality. Structural Equation Modeling with Partial Least Squares (SEM-PLS) was applied for hypothesis testing and model development. Results: The model showed moderate explanatory power (R² = 0.223 for family empowerment; R² = 0.115 for complementary feeding quality). Demographic, educational, technological, economic, and cultural factors significantly influenced family empowerment (p < 0.05), which in turn had a strong positive effect on quality (β = 0.340, p < 0.001). Family empowerment mediated the relationship between these factors and quality. Key contributors included knowledge, technology access, income level, and cultural practices. Conclusions: The proposed transcultural care-based family empowerment model effectively improves quality. Strengthening health education, supporting community health volunteers, and integrating culturally sensitive practices, such as encouraging paternal involvement and shared meals, should be prioritized in stunting prevention programs. The model may be adapted for use in similar community settings to enhance program effectiveness. Full article

Cloud imagery analysis from terrestrial observation points represents a fundamental capability within contemporary atmospheric monitoring infrastructure, serving essential functions in meteorological prediction, climatic surveillance, and hazard alert systems. However, traditional ground-based cloud image segmentation methods have fundamental limitations, particularly their inability to effectively model the graph structure and symmetry in cloud data. To address this, we propose G-CLIP, a ground-based cloud image segmentation method based on graph symmetry. G-CLIP synergistically integrates four innovative modules. First, the Prototype-Driven Asymmetric Attention (PDAA) module is designed to reduce complexity and enhance feature learning by leveraging permutation invariance and graph symmetry principles. Second, the Symmetry-Adaptive Graph Convolution Layer (SAGCL) is constructed, modeling pixels as graph nodes, using cosine similarity to build a sparse discriminative structure, and ensuring stability through symmetry and degree normalization. Third, the Multi-Scale Directional Edge Optimizer (MSDER) is developed to explicitly model complex symmetric relationships in cloud features from a graph theory perspective. Finally, the Uncertainty-Driven Loss Optimizer (UDLO) is proposed to dynamically adjust weights to address foreground–background imbalance and provide uncertainty quantification. Extensive experiments on four benchmark datasets demonstrate that our method achieves state-of-the-art performance across all evaluation metrics. Our work provides a novel theoretical framework and practical solution for applying graph neural networks (GNNs) to meteorology, particularly by integrating graph properties with uncertainty and leveraging symmetries from graph theory for complex spatial modeling. Full article

To investigate the strain patterns and shear failure mechanisms of concrete-filled steel tube (CFT) column-end-plate joints during construction, this study designed and fabricated a scaled model of a standard subway station section based on similarity theory. Model tests were conducted under static earth pressure loads, and a finite element model was constructed for comparative analysis. The study focused on the ultimate bearing capacity, failure modes, and force transmission mechanisms of the joint, and optimized the analysis using reinforcement parameters. The results showed significant stress concentrations at the joint corners and core, with shear forces gradually forming annular cracks in the top slab concrete. The bearing system formed by the steel tube column and flange was the primary force transmission mechanism, and even after damage, the steel tube could still effectively restrain the core concrete. Increasing the steel bar diameter and increasing the number of slab reinforcements parallel to the beam significantly improved the joint’s mechanical properties. Improving the material properties of the reinforcement increased the joint’s stress and displacement capacity. This research provides a reference for optimizing the design and construction of slab-column joints in subway stations. Full article

In the field of tracked vehicle dynamics, studies show that vertical loads are concentrated under road wheels on firm road conditions, allowing slip-based models of tracked vehicles to be designed similar to wheeled vehicle models. This paper proposes a slip-based nonlinear two-track prediction model for model predictive control (MPC), where track forces under road wheels are calculated with a simplification procedure implemented onto shear displacement theory. The study includes a comparative analysis with a kinematic prediction model, examining scenarios such as constant speed cornering and spiral maneuvers. Validation is carried out by comparing the simulation results of the proposed controller with field test data acquired from a five‑wheeled tracked vehicle platform, including measurements on asphalt and stabilized road conditions. The results demonstrate that the slip-based model excels in trajectory tracking, with lateral deviations consistently below 0.25 m and typically around 0.02–0.08 m RMS depending on the scenario. By improving the computational efficiency and ensuring precise navigation, this approach offers an advanced control solution for tracked vehicles on firm terrain. Full article

Reducing energy consumption in belt conveyor systems is critical to improving the overall energy efficiency of lignite mining operations. This study presents a theoretical and empirical analysis of energy use in overburden and coal conveyors, with a focus on balancing the relationship between belt speed and load. Building on the theory of conveyor motion resistance, the energy consumption index (WskZE)—previously introduced by the authors—is revisited as a function of two key variables: belt speed (v) and real-time material flow rate (Q_r). Empirical validation was conducted using operational data from variable-speed conveyors in the Konin lignite mine and compared to similar-length conveyors in the Bełchatów mine. Energy consumption measurements allowed for the analysis of energy consumption for two different scenarios: (i) in the Bełchatów mine the belt speed was constant and the excavator capacity was variable and (ii) in the Konin mine the excavator capacity was kept constant and the conveyor belt speed was varied. The results confirm that WskZE is linearly dependent on belt speed and inversely proportional to throughput, as predicted by theoretical models. However, findings also show that lowering belt speed—while effective in reducing energy use—results in a higher proportion of power being consumed to move the belt and heavy idlers, especially when these components are sized for peak loads. This study suggests a revised conveyor design philosophy (a new paradigm) that emphasizes maximizing the mass ratio of transported material to moving components. Additionally, it recommends integrating real-time monitoring of energy performance indicators into mine control systems to enable energy-aware operational decisions. Full article

Low-Altitude and Slow-Speed Small (LSS) targets pose significant challenges to air defense systems due to their low detectability and complex maneuverability. To enhance defense capabilities against low-altitude targets and assist in formulating interception decisions, this study proposes a new threat assessment algorithm based on multisource data fusion under visible-light detection conditions. Firstly, threat assessment indicators and their membership functions are defined to characterize LSS targets, and a comprehensive evaluation system is established. To reduce the impact of uncertainties in weight allocation on the threat assessment results, a combined weighting method based on bias coefficients is proposed. The proposed weighting method integrates the analytic hierarchy process (AHP), entropy weighting, and CRITIC methods to optimize the fusion of subjective and objective weights. Subsequently, Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) and Dempster–Shafer (D-S) evidence theory are used to calculate and rank the target threat levels so as to reduce conflicts and uncertainties from heterogeneous data sources. Finally, the effectiveness and reliability of the two methods are verified through simulation experiments and measured data. The experimental results show that the TOPSIS method can significantly discriminate threat values, making it suitable for environments requiring rapid distinction between high- and low-threat targets. The D-S evidence theory, on the other hand, has strong anti-interference capability, making it suitable for environments requiring a balance between subjective and objective uncertainties. Both methods can improve the reliability of threat assessment in complex environments, providing valuable support for air defense command and control systems. Full article

Graph anomaly detection (GAD) is crucial for safeguarding the integrity and security of complex systems, such as social networks and financial transactions. Despite the advances made by Graph Neural Networks (GNNs) in the field of GAD, existing methods still exhibit limitations in capturing subtle structural anomaly patterns: they typically over-rely on reconstruction error, struggle to fully exploit structural similarity among nodes, and fail to effectively integrate attribute and structural information. To tackle these challenges, this paper proposes a structure-aware dual-path attention graph node anomaly detection method (DPGAD). DPGAD employs wavelet diffusion to extract network neighborhood features for each node while incorporating a dual attention mechanism to simultaneously capture attribute and structural similarities, thereby obtaining richer feature details. An adaptive gating mechanism is then introduced to dynamically adjust the fusion of attribute features and structural features. This allows the model to focus on the most relevant features for anomaly detection, enhancing its robustness and antinoise capability. Our experimental evaluation across multiple real-world datasets demonstrates that DPGAD consistently surpasses existing methods, achieving average improvements of 9.06% in AUC and 11% in F1-score. Especially in scenarios where structural similarity is crucial, DPGAD has a performance advantage of more than 20% compared with the most advanced methods. Full article

In recent years, replacing the scarce and expensive rare earth element Nd with the more abundant and lower cost Ce in the production of Nd-Ce-Fe-B permanent magnets has become a focus of both industrial and academic research. A critical challenge is how to design the crystal structure of Nd-Ce-Fe-B magnets to compensate for the decline in magnetic performance caused by the Ce substitution. In this study, based on micromagnetic theory, Nd-Ce-Fe-B magnets with perpendicularly oriented easy axes—in which the two main phases, Nd₂Fe₁₄B and Ce₂Fe₁₄B, have a volume ratio of 1:1 but different spatial arrangements—are modeled and simulated using the MuMax3.11 software. The model is either cubic or spherical. The results from the demagnetization curve analysis indicate that the coercivity mechanism of all magnets is pinning. When the magnet volume is constant but the phase distribution differs, the Nd₂Fe₁₄B/Ce₂Fe₁₄B structure exhibits a higher coercivity and maximum energy product than the Ce₂Fe₁₄B/Nd₂Fe₁₄B structure. Furthermore, for both structural models with the same phase distribution, the coercivity and the maximum energy product decrease with the increasing volume of the main phase. Notably, the coercivity is similar when the magnet volume is very small and stabilizes after reaching a certain threshold. This qualitative conclusion was also observed in Nd-Dy-Fe-B magnets with the same structure and equal volume ratio of the two main phases. This general finding indicates that, in biphasic magnets with equal phase volumes, the phase with the larger anisotropy field located at the grain periphery can achieve a higher coercivity and maximum magnetic energy product. The analysis of the angular distribution reveals that the number of magnetic domains remains fixed at six in the Nd₂Fe₁₄B/Ce₂Fe₁₄B structure and two in the Ce₂Fe₁₄B/Nd₂Fe₁₄B structure. The in-plane magnetic moment analysis of the Ce₂Fe₁₄B/Nd₂Fe₁₄B magnet shows that the magnetic moments at the edges of the Ce₂Fe₁₄B begin to deflect first. Even at the pinning stage, the magnetic moments within the Nd₂Fe₁₄B remain unrotated. Nevertheless, the surface magnetic moments of Ce₂Fe₁₄B, through exchange coupling, drive the deflection of the interfacial and interior moments, completing the entire demagnetization process. These computational results provide theoretical guidance for related experimental studies and industrial applications. Full article

Tight oil is an important resource replacement in the petroleum industry, with the reserves of Type-II energy accounting for over 40%. However, these reservoirs have small pore throats and complex structures, and their wettability directly affects the EOR by affecting the occurrence of crude oil and multiphase flow mechanisms. In response to an unclear understanding of the evolution mechanism of wettability after energy replenishment in tight reservoirs with different reservoir formation conditions, the evolution law of wettability in different energy replenishment media for tight type-II reservoirs is evaluated by performing wettability experiments and nuclear magnetic resonance experiments, and the mechanism of differential changes in wettability after energy replenishment in different media is elucidated. The results show that the block with well-developed pores and good connectivity (Block: Z401) had the smallest in situ wetting angle, ranging from 27.1° to 30.4°, and that the interface effect had a small impact, resulting in a small change in the wetting angle after energy replenishment. The wetting angle of the developmental intersection block (Block: G93) is the highest, ranging from 36.6° to 46.4°. The connected pore and throats fully interact with the medium at the interface, resulting in a significant change in the wetting angle. In addition, after natural gas energy supplementation, the principle of similar solubility causes a significant change in the wetting angle of the pore throat interface after adsorption, with a maximum angle of 19.6°. The change in the wetting angle change of the CO₂ mixed-phase principle is in the middle, at about 13.6°, while the change in the wetting angle is minimal after N₂ replenishment, around 10°. The research results improve our understanding of the basic theory of tight oil supplementary energy development and have important practical significance. Full article

This study investigates the structural transformation from the γ-phase into the α-phase in bio-based nylon 5,6 fibers during in situ uniaxial stretching, using X-ray diffraction (XRD) and density functional theory (DFT) calculations. Initially, nylon 5,6 films exhibited a well-defined γ-phase crystalline structure, and the as-spun fibers also retained a γ-phase-dominant structure with partial coexistence of α-phase components. Due to the lattice similarity between the γ- and α-phases, phase separation was challenging in the direction perpendicular to the fiber axis (ab-plane). However, the analysis of the (004) diffraction peaks along the fiber axis (c-axis) enabled the quantitative evaluation of each crystalline component. As the stretching progressed, the α(004) peak intensity gradually increased, indicating a continuous γ-to-α structural transition. Furthermore, DFT calculations revealed that the α-phase has lower energy than the γ-phase, supporting the thermodynamic favorability of the phase transition during elongation. These results provide a comprehensive understanding of the crystalline structure and transformation mechanism in environmentally friendly nylon fibers from both experimental and theoretical perspectives, and offer foundational insights for developing nylon materials with desirable properties through the precise control of crystal phase structures. Full article

Background: Youth suicide is a global issue and a type of death that can be prevented through early access to evidence-based mental health interventions, which can contribute to improved quality of life as well as health, educational and employment outcomes. Young people are encouraged to seek help for mental health problems, yet help-seeking rates remain low. Objective: The aim of this research was to explore how young people with a mental health problem decide to search and ask for professional help, and the impact of help-seeking experiences. Methods: Young people aged 16–25 years with experiences of help-seeking to mental health services were recruited (N = 18). Data analysis was informed by Constructivist Grounded Theory methods, and the findings were presented across four sub-categories: 1. Deciding to Seek Help; 2. Searching for the Right Help; 3. Reflecting on Help-seeking Experiences; and 4. Living with the Impacts of Help-seeking. Findings: Young people often sought help while highly distressed and required the skills and resources of a family member or friend to access the right type of help. Help-seeking was multi-episodic and had lasting positive and negative impacts. Young people’s help-seeking patterns were found to be similar to the ways in which they problem-solve in learning contexts, and the concept of a formal help-seeking skillset was presented. Full article

This study investigates the impact of weak water-rich aquifers overlying shallow-buried thin bedrock coal seams on mining support systems. By applying Terzaghi’s theory to the evolutionary characteristics of the overburden structure in loose aquifers, a mechanical model for load transfer from the aquifer is established, and a calculation formula for the maximum working resistance of the support is derived. The results are validated using field mine pressure data from the 1010–1 working face of Wugou Coal Mine. The findings show that the overlying load of the key stratum is positively correlated with the water pressure in the aquifer; the higher the water pressure, the greater the overlying load, which leads to increased instability of the key stratum and a higher likelihood of support crushing. Additionally, the thickness of the bedrock is negatively correlated with the aquifer water pressure load transfer coefficient, meaning that a thicker bedrock layer reduces the impact of the aquifer’s water pressure on the key stratum, with a critical thickness of 50 m. Moreover, the working resistance of the support is positively correlated with the water pressure, and the pressure intensity at the working face in the aquifer-covered area after grouting reconstruction is about 33% higher than in non-aquifer-covered areas. The results provide a theoretical basis for safe mining in similar geological conditions and offer guidance for the selection of support systems. Full article