Search Results (153)

A study was conducted on the construction of sulfonated poly(aryl ether ketone) nanomicelles and their dispersion–displacement synergistic behavior in deep oil recovery. Unlike conventional surfactant systems, inorganic nanoparticle-based EOR materials, and polymeric nanofluids that mainly rely on interfacial tension reduction, wettability alteration, or viscosity regulation, this study constructs self-assembled sulfonated poly(aryl ether ketone) nanomicelles that integrate a rigid aromatic backbone, ionizable sulfonic acid groups, nanoscale dispersion, and interfacial regulation within one polymeric architecture. Sulfonated poly(aryl ether ketone) nanomicelles were prepared by combining polymer sulfonation with solvent-induced self-assembly, and their structural features, dispersion stability, interfacial behavior, porous-media transport, and displacement performance were systematically evaluated. Spectroscopic characterization confirmed the successful introduction of sulfonic acid groups into the polymer backbone. The resulting nanomicelles exhibited an average hydrodynamic diameter of 117.8 nm, a polydispersity index of 0.186, and a zeta potential of −38.6 mV in deionized water, while a value of −27.4 mV was still maintained at a salinity of 150,000 mg/L, indicating good electrostatic stability under highly mineralized conditions. Further evaluation showed that the 0.30 wt% system retained a transmittance of 97.4% after 15 d of static standing, and its particle size remained at 151.7 nm even under 120 °C and 150,000 mg/L, demonstrating favorable thermal–salinity tolerance. At the same concentration, the oil–water interfacial tension decreased to 6.9 mN/m at 1800 s, while the contact angle of oil-aged quartz was reduced from 118.4° to 58.7°, indicating effective regulation of both the oil–water interface and the solid surface wettability. During microscopic displacement, the residual oil area fraction decreased from 32.8% after water flooding to 14.6%, and cluster-like oil, corner oil, and film-like oil were reduced from 14.6%, 9.8%, and 8.4% to 5.9%, 4.2%, and 4.5%, respectively. In core flooding, the incremental oil recovery reached 13.2%, the final water cut decreased to 81.2%, and the injection pressure increased only from 0.42 MPa to 0.68 MPa. These results indicate that sulfonated poly(aryl ether ketone) nanomicelles promote deep residual-oil mobilization through the combined effects of stable dispersion, interfacial regulation, and effective transport, with 0.30 wt% identified as the preferred concentration range. The main scientific contribution of this work is to establish a structure–dispersion–interface–transport–displacement relationship for SPAEK nanomicelles under deep-reservoir conditions, providing a polymeric nanomicelle-based strategy distinct from conventional surfactant, sulfonated polymer, and nanoparticle flooding systems. Full article

The development of highly efficient and stable photoanodes is essential for advancing photoelectrochemical cathodic protection towards practical applications. Herein, a novel ternary sulfide heterojunction was engineered through the construction of a three-dimensional interlocked architecture of ZnIn₂S₄ on SnIn₄S₈ nanosheets via a sequential hydrothermal synthesis. This unique three-dimensional interlocked configuration creates an intimate interface and continuous charge transfer highways, effectively addressing the slow electron movement and poor interfacial contact that plague conventional photoelectrodes. Spectroscopic and electrochemical analyses verified the formation of a Type-II band alignment, which drives the directional migration of photogenerated electrons from ZnIn₂S₄ to SnIn₄S₈ under an intrinsic built-in electric field. Upon coupling with 304 stainless steel, the ZnIn₂S₄/SnIn₄S₃ heterojunction exhibited outstanding photoelectrochemical cathodic protection performance. It delivered impressive photocurrent densities of 15.22, 19.76, and 72.27 μA·cm⁻² in 3.5 wt% NaCl, 0.1 M Na₂S₂O₃, and 0.1 M Na₂S/NaOH electrolytes, respectively, along with a prominent 720 mV cathodic potential shift in the Na₂S/NaOH system. Most importantly, its good activity and stability in the scavenger-free 3.5 wt% NaCl solution and natural seawater highlight the strong practical potential of this 3D interlocked photoanode for sustainable marine metal corrosion control. Through a strategic multi-electrolyte assessment, the underlying protection mechanisms were decoupled, revealing that the synergy between the heterojunction-induced charge separation enabled by the three-dimensional interlocked structure and electrolyte-specific hole scavenging is key to the enhanced performance. Full article

The excavation of deep shafts using Vertical Shaft Sinking Machine (VSM) technology in stratified soft soils involves complex soil-structure interaction (SSI) mechanisms that are often oversimplified by conventional numerical approaches. This study develops a robust three-dimensional numerical framework to investigate ground deformation induced by VSM operations, explicitly incorporating the phased construction sequence, segmental lining installation, and site-specific stratigraphy. The model is calibrated and validated against high-resolution field monitoring data, employing a prediction envelope approach and statistical performance metrics (RMSE and R2). The results suggest that ground response during VSM excavation is predominantly stiffness-controlled under the investigated conditions. Mobilized shear stresses remain significantly below the available soil capacity, indicating that deformation under serviceability conditions is driven by progressive strain accumulation. Horizontal displacement profiles suggest a relatively stable depth of influence, indicating that the excavation process amplifies deformations within a pre-established domain without significant deep-seated propagation. Sensitivity analyses indicate soil stiffness modules (E50,Eoed,Eur) and the SSI interface factor (Rinter) as the primary drivers of deformation magnitude. Furthermore, stratigraphic contrasts specifically clay-sand sequences, act as a mechanical filter, concentrating strains in soft layers while limiting vertical propagation through stiffer strata. The proposed framework provides a mechanically coherent basis for serviceability-oriented design, deformation prediction, and risk-mitigation strategies for mechanized shafts in saturated soft ground. Full article

Direct current (DC) surface flashover on polystyrene (PS) remains a critical bottleneck that impedes its reliable application in high-voltage insulation apparatus. To circumvent the protracted processing durations and stringent film-forming conditions inherent in conventional surface modification techniques, this study proposes a novel “liquid-film-assisted in situ rapid plasma curing” strategy. By harnessing atmospheric-pressure dielectric barrier discharge (DBD) technology within an argon ambient, the rapid (<6 min) and efficient deposition of a fluorosilane (FAS-13) functional coating onto the substrate was achieved. Microscopic characterizations coupled with isothermal surface potential decay (SPD) measurements reveal that this coating substantially mitigates the detrapping and surface migration of charge carriers. Macroscopic DC flashover testing corroborates that, under the optimal modification ratio, the surface breakdown voltage of PS is elevated to 14.04 kV, yielding an insulation gain of 26.94%. To elucidate the underlying physical mechanisms, density functional theory (DFT) calculations were conducted, revealing that the energy band misalignment between the wide-bandgap fluorinated layer and the substrate facilitates the construction of a high-density deep trap network (with a depth of ~0.8 eV) at the coating–substrate interface. By robustly anchoring primary electrons and inducing the formation of a homopolar space charge shielding layer, these deep traps physically arrest the evolution of the secondary electron emission avalanche (SEEA). Consequently, this work not only establishes a viable engineering framework for the rapid, large-scale surface reinforcement of DC insulation equipment but also provides profound quantum chemical insights into interfacial trap regulation within all-organic dielectrics. Full article

Interfacial stress concentration induced by curing shrinkage during the manufacturing of epoxy resin is a primary trigger for micro-nano defect formation and electrical performance degradation in power equipment. To address the computational complexity of traditional viscoelastic models and the thermoelastic behavior wherein the stiffness of the epoxy resin varies with temperature during curing, this paper proposes an improved viscoelastic constitutive model incorporating a thermo-elastic factor. By coupling curing kinetics, heat conduction, chemical shrinkage, and mechanical effects, a multi-physics simulation framework is constructed to describe the complete epoxy curing process, thereby revealing the spatiotemporal evolution of curing stress deformation. To verify the model’s accuracy, an in situ monitoring system based on Fiber Bragg Grating (FBG) sensors was established. A temperature compensation method was utilized to effectively decouple temperature and stress within the complex exothermic curing environment. This study reveals a significant strain gradient effect during the resin curing process. Experimental measurements indicate strains of 21,609 με and 5800 με at the interface and surface, respectively, with numerical simulations exhibiting high agreement with the experimental data. This research not only provides an efficient simulation approach for predicting curing stress but also offers a theoretical basis for the crack-resistant structural design of high-performance epoxy-based power equipment. Full article

Hydro-wind-solar hybrid power systems have become a mainstream configuration for new-type power systems. However, the high proportion of power-electronics-interfaced generation alters system inertia and damping characteristics, leading to complex high-dimensional frequency dynamics and severe stability challenges. This paper investigates the frequency response mechanism and Hopf bifurcation characteristics of the aggregated frequency response model for hydro-wind-solar hybrid power systems. First, primary frequency response models for hydropower, wind power, and photovoltaic (PV) generation are established under a small-signal analysis framework. On this basis, a tenth-order nonlinear dynamic model of the integrated system is constructed by considering hydraulic nonlinearities, virtual inertia control of wind power, and reserve-based frequency regulation of PV systems. Then, Hopf bifurcation theory is applied to analyze stability and oscillatory instability mechanisms of the high-dimensional system. The bifurcation conditions are derived via high-dimensional Jacobian matrix analysis and Routh-Hurwitz criterion, with supplementary normal form calculation and first Lyapunov coefficient derivation to identify the supercritical/subcritical nature of the bifurcation. Finally, numerical simulations under both small and large disturbances validate the theoretical analysis. The results demonstrate that variations in key control parameters may induce Hopf bifurcation, leading the high-dimensional system from a stable equilibrium to sustained low-frequency oscillations. The findings provide insights and practical guidance for stable operation and parameter tuning of hydro-wind-solar hybrid power systems. Full article

Magnesium (Mg) alloys are promising for automotive lightweighting and the low-altitude economy, yet their reliability is challenged by stress corrosion cracking (SCC). To realize a quantitative and physics-based evaluation of SCC resistance, this study develops a mesoscale simulation framework coupling dislocation density-based crystal plasticity with an anodic dissolution phase-field model. A 2D representative volume element is constructed for randomly textured polycrystalline Mg to investigate the synergistic acceleration of corrosion by dislocation slip and hydrostatic stress. Results show that heterogeneous dislocation multiplication induced by pre-deformation is the decisive factor in corrosion path selection. In soft-oriented grains, high dislocation densities elevate the interface kinetic coefficient to levels substantially higher than those in hard-oriented regions. Notably, within such soft grains, the contribution of dislocation density to the interface kinetic coefficient can be up to 7.7 times that of hydrostatic stress, establishing dislocation-induced lattice disorder as the primary accelerator for transgranular corrosion. Hard-oriented grains effectively impede corrosion propagation due to restricted dislocation proliferation. This study elucidates how grain orientation-dependent dislocation evolution regulates corrosion morphology, revealing that the random texture delays overall structural failure based on a “weakest-link” mechanism. Full article

We formulate a covariant mechanical equilibrium condition for the quark–hadron mixed phase boundary in the presence of a magnetic-field-induced pressure anisotropy. Using the relativistic thin-shell formalism to describe the quark–hadron boundary, we interpret conservation of stress-energy across the interface as a set of generalized Young–Laplace conditions which characterize the geometry of the interface. In a comoving stationary frame, this provides a covariant description of mechanical equilibrium at the interface, which serves as a replacement for the scalar pressure-balance condition used in the isotropic Gibbs construction. Full article

The driving scenario and information load jointly influence the cognitive efficiency of augmented reality head-up display (AR-HUD) interfaces. However, the moderating role of drivers’ working memory capacity (WMC) remains unclear. To investigate this mechanism, a simulated driving experiment with a mixed design was conducted in a low-immersivity desktop virtual reality (VR) environment. First, 40 volunteers were screened using an automated operation span task, yielding 16 high- and low-WMC participants. They then drove under three scenarios (urban intersection, expressway, construction zone) and six levels of AR-HUD visual information load. Generalized linear models were applied to the reaction time, fixation duration, and pupil diameter. The results revealed a significant three-way interaction among WMC, scenario, and information load. High-WMC drivers maintained faster responses and lower subjective loads up to Levels 4–6, adopting a deep processing strategy; low-WMC drivers already showed cognitive overload at Level 4 and above, requiring an optimal load range of Level 2–3. The construction zone induced the steepest increase in cognitive load, whereas the expressway markedly reduced sensitivity to additional visual information. Therefore, the optimal AR-HUD information load must be adapted to drivers’ WMC: high-WMC drivers can safely handle Levels 4–6 in low- or medium-demand scenarios, whereas low-WMC drivers require a minimalist presentation of Levels 2–3 in high-demand situations. This study provides quantitative, empirically grounded guidelines for designing cognitively adaptive AR-HUD interfaces. Full article

To improve the visible-light-driven photocatalytic degradation efficiency of g-C₃N₄-based photocatalysts toward organic pollutants, a MoS₂/g-C₃N₄ composite precursor was employed in this work, and the phase composition and defect environment of Mo species were regulated by post-annealing under air and N₂ atmospheres, respectively, thereby constructing Mo-based/g-C₃N₄ (MCN) composites with distinct structural evolution characteristics. The results showed that the photocatalytic activity of the as-sonicated MCN composite toward methylene blue (MB) was only moderately improved, among which the 15% loading sample exhibited the best performance with a degradation efficiency of about 42.0% within 60 min. In contrast, annealing at 400 °C under N₂ resulted in only a slight activity change, whereas the sample treated at 400 °C in air (Air-15% MCN) achieved an MB degradation efficiency of 99.9% within 60 min, together with a much higher pseudo-first-order reaction rate constant than that of the air-treated sample at a lower temperature. XRD, FT-IR and XPS analyses revealed that air annealing induced the conversion of MoS₂ into highly crystalline MoO₃ (or MoO_3−x), leading to the formation of a reconstructed MoO_3−x/g-C₃N₄ composite interface. Meanwhile, the increased high-binding-energy component in the O 1s spectrum and the EPR signal around g ≈ 2.00 further suggested the presence of more abundant defect-related centers in the air-treated sample. Although Air-15% MCN possessed a lower specific surface area than the untreated and N₂-treated samples, it displayed enhanced visible-light absorption, higher transient photocurrent response, lower interfacial charge-transfer resistance, and accelerated carrier dynamics, indicating that the activity enhancement mainly originated from atmosphere-induced phase transformation, interfacial reconstruction, defect-related active centers, and improved charge separation/transfer, rather than from the surface area effect. Based on the above results, a possible interfacial charge-transfer pathway is tentatively proposed for the g-C₃N₄/MoO_3−x interface formed after air treatment, which contributes to the efficient utilization of photogenerated carriers and the rapid degradation of MB. This work demonstrates that atmosphere-induced phase transformation is a simple and effective strategy for regulating the structure and photocatalytic performance of Mo-based/g-C₃N₄ composites, and provides useful guidance for the design of efficient visible-light photocatalysts. Full article

During the production, storage, and use of solid rocket motors, the impact generated by unexpected accidents, such as collision or drop, will cause damage to the propellant and affect the safety of the motor. However, the progressive evolution mechanism of mesoscopic damage in NEPE propellant under such impact conditions has not been fully elucidated, and there is still a lack of quantitative method to evaluate the impact-induced damage degree, which restricts the engineering safety assessment of solid rocket motors. To investigate the influence mechanism, the mesoscale damage characteristics of NEPE propellant under drop-weight impact is systematically studied. First, damaged NEPE specimens are obtained by conducting drop-weight experiments with a 10 kg hammer, where the drop height is varied to apply different impact impulses. The internal meso-structure of the propellant is then characterized using micro-CT, yielding detailed imagery of the refined meso-structural features and damage morphologies in the NEPE propellant. To capture the dynamic evolution process of mesoscale damage, a mesoscopic model incorporating AP, Al, HMX particles and voids, is subsequently constructed based on the high-precision mesoscopic morphology characterized by micro-CT. By integrating the deviatoric constitutive model, Gurson plastic damage model, and bilinear cohesive zone model, high-fidelity numerical simulations of the drop-weight impact damage process are performed using the advanced SPH-FEM coupling algorithm. The results indicate that no significant damage occurs when the impact impulse is less than 13.85 N·s. As the impulse increases, phenomena including matrix microcracks, void collapse, particle/matrix interface debonding, and main crack formation appear sequentially. When the impulse exceeds 24.25 N·s, particle fragmentation and transgranular fracture occur, accompanied by plastic flow and frictional heating that induce ignition. Finally, the overall damage degree is fitted by the Boltzmann function, and a function for quantitatively describing the damage degree is obtained, which can provide theoretical support for the impact safety assessment of solid rocket motors. Full article

The sluggish kinetics of the hydrogen oxidation reaction (HOR) in alkaline media remain a primary bottleneck for anion exchange membrane fuel cells (AEMFCs), necessitating catalysts that synergistically optimize the adsorption of hydrogen (*H) and hydroxide (*OH) intermediates. Herein, we construct a well-defined heterointerface between Pd clusters and CeO₂ on nitrogen-doped carbon (Pd-CeO₂/NC) to electronically engineer the active sites. Spectroscopic studies and theoretical calculations collectively reveal that CeO₂ acts as an electron acceptor, drawing electrons from Pd via interfacial Pd-O-Ce bridges. This charge transfer induces a downshift of the Pd d-band center, which optimally tunes the adsorption strength of both *H and *OH at the interface, thereby breaking the scaling relationship that limits HOR activity. The resulting Pd-CeO₂/NC catalyst achieves an exceptional exchange current density of 3.66 mA cm⁻², surpassing that of commercial Pt/C by a factor of two and ranking among the best reported noble metal catalysts. Furthermore, it exhibits outstanding long-term stability and remarkable CO tolerance, retaining high activity in an atmosphere containing 1000 ppm CO. This work underscores the profound efficacy of metal–oxide heterointerface engineering in regulating electronic structures for multi-intermediate optimization, offering a viable design principle for advanced alkaline HOR electrocatalysts. Full article

To address the strong nonlinearity of aerodynamic loads during projectile exterior ballistic flight and the difficulty in accurately modeling fuze dynamic responses, this paper proposes a data-driven modeling and simulation method for fuze exterior ballistic dynamics. A high-fidelity aerodynamic database covering a range of Mach numbers and angles of attack is constructed based on CFD (Computational Fluid Dynamics) simulations. An MLP (Multilayer Perceptron) neural network is then employed to develop an aerodynamic surrogate model, enabling continuous representation of aerodynamic loads within the given sample space. The results show that, within the data coverage range, the proposed model is able to capture the nonlinear variation in aerodynamic parameters and shows improved prediction accuracy compared with the polynomial fitting method. Specifically, for typical aerodynamic parameters, the RMSE (Root Mean Square Error) is reduced from 5.758 to 0.223, the MAE (Mean Absolute Error) is reduced to 0.099, and the R² (Coefficient of Determination) approaches 1. On this basis, the aerodynamic surrogate model is embedded into a six-degree-of-freedom projectile–fuze exterior ballistic dynamics model via the secondary development interface of ADAMS 2020 (Automated Dynamic Analysis of Mechanical Systems), enabling coupled simulation between aerodynamic loads and multibody dynamics. Comparison with firing table data indicates that, under typical operating conditions, the relative deviation of ballistic parameters is generally better than 94%, demonstrating that the proposed method can reasonably reproduce the projectile exterior ballistic characteristics. Furthermore, based on the coupled dynamics model, the dynamic response characteristics of the fuze moving body during the exterior ballistic phase are analyzed. The results indicate that the axial forward overload of the moving body increases significantly with the initial nutation angle, and the variation in the axial projection of gravity induced by nutation plays an important role in its transient response. The proposed approach provides a useful reference for the dynamic response analysis and safety evaluation of fuzes. Full article

With the growing trend toward insulator hybridization, higher requirements are imposed on the synergistic improvement of interfacial durability and pollution flashover performance. Machining annular grooves at the green-body stage and embedding silicone rubber enables the construction of an embedded structure with improved durability, forming hydrophilic/hydrophobic alternating surfaces. However, the outdoor insulation characteristics of such hybrid surfaces remain insufficiently investigated, and their engineering feasibility requires further validation. In this study, a series of hydrophilic/hydrophobic alternating surfaces were fabricated, and artificial pollution tests were conducted. The results show that the AC pollution flashover voltage exhibits a saturated increasing trend as the hydrophobic interfaces become more dispersed. When twenty 4 mm wide hydrophobic interfaces were distributed along a 16 cm creepage distance, the flashover voltage was 12.4% higher than that of a fully hydrophobic surface. These results indicate that appropriate design of hydrophobic interface distribution can achieve excellent pollution flashover performance even at relatively low hydrophobic coverage (≤50%). High-speed imaging combined with infrared thermography reveals the discharge mechanism governed by hydrophobic interface distribution from an electro–thermal coupling perspective. The coexistence of multiple dry bands induced by discrete hydrophobic interfaces is identified as the key factor enhancing flashover withstand capability. A static pollution flashover model was established to quantitatively estimate the AC flashover voltage, confirming the external insulation feasibility of the embedded hybrid concept. Full article

Titanium implants are widely used in orthopedic and dental fields but often face challenges such as insufficient osseointegration and peri-implant inflammation. While Strontium (Sr) possesses potent bioactive properties, achieving its controlled delivery at the implant-tissue interface remains technically challenging. To address this, we engineered a multidimensional composite coating by constructing a micro/nano-porous TiO₂ substrate via micro-arc oxidation (MAO), followed by polydopamine (PDA)-assisted Sr immobilization. This integrated architecture significantly enhanced surface hydrophilicity and facilitated high-content Sr loading with sustained release kinetics. Biological evaluations demonstrated that the PDA-mediated interface promoted superior initial adhesion and spreading of bone marrow mesenchymal stem cells (BMSCs), synergizing with released Sr²⁺ to markedly upregulate core osteogenic markers (Runx2, ALP). Crucially, the functionalized surface actively optimized the immune microenvironment by inducing M1-to-M2 macrophage polarization and comprehensively suppressing RANKL-induced osteoclastogenesis via the downregulation of TRAP and DC-STAMP. By integrating these pro-osteogenic, anti-inflammatory, and anti-resorptive capabilities, this tri-functional system effectively rebalances the bone remodeling microenvironment. Consequently, it provides a robust, universally applicable strategy for enhancing the therapeutic efficacy of next-generation orthopedic and dental implants. Full article