Dynamic multi-objective optimization problems (DMOPs) have attracted significant attention in recent years. However, some existing approaches do not fully exploit the geometric structure of the Pareto optimal front, or rely on relatively coarse distance-based matching, which may lead to less accurate solution alignment and degraded prediction performance under dynamic changes. To address these issues, this paper proposes a Topological Prior and Vector Migration-based Multi-Objective Evolutionary Algorithm (TPV-MOEA) to enhance sub-region partitioning and improve prediction accuracy. Specifically, TPV-MOEA incorporates a two-layer graph-based topological aggregation module to aggregate neighborhood information of shared points, enabling topology-aware ordering along the Pareto front manifold for more reliable sub-region partitioning. Within each sub-region, a vector migration strategy is employed to adaptively transfer global MOEA/D reference vectors into local regions, enabling better alignment with the underlying Pareto front structure and achieving more accurate association between non-dominated solutions and their historical counterparts. New populations are generated through direction-guided alignment and position prediction, thereby enabling effective adaptation to dynamic environmental changes. Comparisons with five state-of-the-art algorithms show that TPV-MOEA achieves superior convergence and diversity in tracking the Pareto front under dynamic environments.
In order to solve the problems of low combustion rate, difficult ignition and high NOx emission in the combustion of ammonia alone, the co-combustion characteristics and reaction mechanism of ammonia/n-heptane (C7H16) (as a diesel substitute) blends were systematically investigated from the micro level by using the method of ReaxFF MD simulation and density functional theory (DFT) calculation. The effects of temperature (1500-3000 K), oxygen molecule quantity (200-500), and fuel blending ratio (alpha = 0-0.2) on the combustion process are explored. Variations in reactant consumption, product formation, free radical concentrations, and key reaction pathways within the blended system are analyzed. Additionally, the energy profiles of major reactions are calculated via DFT. The results indicate that both increased temperature and higher oxygen concentration significantly promote ammonia reaction and accelerate the combustion process. The incorporation of n-heptane promotes the generation of active free radicals such as OH and HO2 through pyrolysis, facilitating more frequent reactions between ammonia and these radicals and thereby reducing the apparent activation energy of ammonia combustion. Simultaneously, n-heptane modulates the reaction pathways of ammonia, directing more combustion products toward nitrogen (N2) formation and effectively suppressing NO generation. The reaction NH3 + OH -> NH2 + H2O is the favorable kinetic path for the initial reaction of ammonia (Gibbs energy barrier 24.0 kJ/ mol). This study reveals the micro-scale mechanisms of ammonia/n-heptane co-combustion at the molecular level and provides molecular-level theoretical support for the combustion optimization and pollutant control of ammonia-based blended fuels.
Simultaneous removal of NOx and VOCs from coke oven flue gas is challenging due to the presence of alkali salts and sulfur. This study investigates the deactivation mechanism of V-Mn-Co (VMC) composite oxide catalysts by Na2SO4, which simulates the dual poisoning effects of desulfurizer residues (NaHCO3) and trace SO2. The VMC catalyst exhibited a NOx conversion of 100% and ethylene conversion of 70% at 240 degrees C, while Na2SO4 poisoning caused a sharp decline to 71% and 16%, respectively. Characterization results revealed that Na2SO4 preferentially deposited on the active (311) crystal plane. Crucially, XPS analysis revealed a divergent shift in binding energies: V 2p shifted to higher values while O 1s shifted to lower values. This indicates a severe polarization of the V-O bond, where the sulfate group withdraws electrons from Vanadium, forcing electron density towards Oxygen. This enhanced ionic character stabilizes the lattice oxygen, effectively 'locking' it and inhibiting the Mars-van Krevelen (MvK) redox cycle. In situ DRIFTs indicated that the accumulation of sulfate species blocked Br & oslash;nsted acid sites, severing the Eley-Rideal (E-R) pathway for NH3-SCR. Furthermore, Grand Canonical Monte Carlo (GCMC) simulations combined with a novel Competitive Impact Rate (CIR) metric quantitatively prove that Na2SO4 intensifies the competitive adsorption between NH3 and ethylene.
The total and scattered field decomposition (TSFD) technique is widely used for electromagnetic scattering problems due to its advantages of accurately portraying the scattered field and reducing the numerical error associated with the incident field reflections in the total field domain. In this paper, we propose an interior penalty discontinuous Galerkin (IPDG) method combined with the TSFD technique for solving the frequency-domain electromagnetic scattering problems. We establish the reliability and efficiency of the a posteriori error estimator for piecewise positive constant electromagnetic parameters. The proposed algorithm is applicable for complex electromagnetic materials. We validate the convergence of the estimator for DG energy errors for both low and high frequencies. Furthermore, we demonstrate the efficiency of the adaptive IPDG method through three interesting physical simulation experiments.
An efficient p–n heterojunction CoWO4/Zn(Ti)O photocatalyst was developed via a hydrothermal-calcination route. Owing to the uniform decoration of CoWO4 nanoparticles on Zn(Ti)O nanosheets, a compact heterointerface was established, which substantially improved photogenerated carrier separation and interfacial electron transfer. The intimate p–n junction facilitated reactant diffusion, increased the density of accessible surface-active sites, and minimized charge migration distances, thereby enabling remarkable photocatalytic performance toward visible-light-driven Cr(VI) reduction (98.9% removal rate) and methyl orange degradation (99.3% removal rate). Spectroscopic and electrochemical analyses, including UV–vis diffuse reflectance spectroscopy and Mott–Schottky measurements, verified the formation of the p–n heterojunction and the associated charge-transfer behavior. This work presents an effective pathway for constructing advanced p–n heterojunction photocatalysts for environmental restoration.
