Automotive cooling fans play a vital role in thermal management, yet conventional designs often struggle to balance efficiency, pressure, and flow requirements. This work presents a multiobjective optimization of an axial-flow fan using response surface methodology and a genetic algorithm. Four critical parameters (the root and tip installation angles and sweep angles) were optimized with respect to volumetric flow rate (Q), static pressure (P), and efficiency (η). A surrogate model built from 25 Latin Hypercube Sampling points achieved high accuracy (R 2 > 0.99). Sensitivity analysis showed that the tip angle predominantly affects Q and P, while the root angle strongly influences η. Optimization yielded Pareto solutions, where the efficiency improved from 18.31% to 21.19% without reducing the flow or pressure. The flow-field analysis demonstrated that the enhanced aerodynamic stability is addressed in the enhanced aerodynamic stability, characterized by smoother velocity profiles and reduced regions of separation and recirculation. The proposed framework not only improves fan aerodynamic efficiency but also establishes a generalizable strategy for systematic multiobjective optimization of rotating machinery.

This study proposes a vibration reduction strategy for a 12-slot, two-pole permanent magnet brushed DC (PMDC) motor used in automotive blower systems. A multi-parameter optimization framework combining finite element analysis and experimental validation is developed to address cogging torque, a critical source of electromagnetic vibration and acoustic noise. The influence of pole arc coefficient and permanent magnet eccentricity on cogging torque is systematically investigated using response surface methodology, identifying an optimal design with significantly reduced torque ripple and vibration. Furthermore, a machine learning model based on the random forest algorithm is introduced to predict cogging torque, air gap magnetic flux density, and output torque, achieving high accuracy and strong generalizability. The results confirm that the optimized motor structure suppresses resonance-induced noise near 7500 Hz, improving overall motor stability and acoustic performance. The proposed data-driven design approach offers a reliable and efficient pathway for vibration optimization in low-cost automotive PMDC motors.

PurposeThis study aims to explore energy fluctuations during fluororubber-copper friction under varying normal loads using molecular dynamics simulations and elucidates the load-induced mechanisms that govern these fluctuations.Design/methodology/approachA fluororubber model containing 70 Wt.% vinylidene fluoride-hexafluoropropylene was constructed using AutoFF and the OPLS-AA force field and relaxed in LAMMPS via a series of NVT simulations at 298.15 K with a 1 fs time step. A layered fluororubber-copper friction model was then built and further equilibrated. Sliding was simulated at a constant velocity under normal loads of 100, 2,000 and 10,000 MPa for up to 3,000 ps. OVITO was used for post-processing and visualization of molecular structures and temperature fields.FindingsIncreasing normal load significantly amplifies energy fluctuations in the fluororubber-copper system. Decomposition of the potential energy shows that bond-stretching and bond-angle terms dominate the load-induced energy fluctuations, whereas nonbonded interactions exhibit much smaller variations.Originality/valueThis work fills a gap in understanding how normal load influences molecular-scale energy dissipation in fluororubber-metal friction. By establishing a direct link between load, conformational changes and the associated bonded energy fluctuations, this study provides valuable insights for the design and optimization of fluororubber components used in high-load tribological environments.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2025-0405

Intrinsic lattice vibrations are conventionally regarded as merely a thermal perturbation in photocatalysis, leaving their potential as an active control parameter largely unexplored. Here, we demonstrate that selectively activated intrinsic phonon modes can act as an internal driving force to dynamically regulate photocatalytic functionality. Using first-principles calculations on a Janus MoSSe/WSSe van der Waals heterostructure, we reveal that mode-selective lattice vibrations profoundly reshape the electronic structure and photocarrier transfer pathways. In particular, high-frequency intralayer phonon modes induce pronounced bandgap renormalization and trigger a qualitative transition in charge-transfer behavior, enabling a shift from conventional type-II separation toward an S-scheme-like catalytic regime. This phonon-driven electronic reconstruction optimizes metal d-band characteristics and metal–adsorbate interactions, thereby enhancing the catalytic activity for both hydrogen and oxygen evolution reactions. Our results uncover a direct, symmetry- and mode-dependent coupling between lattice vibrations and catalytic activity, establishing targeted phonon excitation as a promising and physically transparent strategy for activating high-performance photocatalysis beyond static structural design.

Low interfacial thermal conductance often emerges as a primary barrier to effective heat management in advanced nanodevices. This study examines how topological defects affect the interfacial thermal conductance of graphene/SiC lateral heterostructure, utilizing nonequilibrium molecular dynamics simulations. The significant lattice mismatch between graphene and SiC results in a pristine interface that experiences severe strain and structural distortion, ultimately reducing the level of phonon transmission. By introduction of 5|8|5 topological defects, the interfacial deformation is effectively alleviated, thereby improving phonon coupling across the boundary. The results reveal an unconventional increase in interfacial thermal conductance, with the maximal value achieved when three defects are incorporated, representing a 61% improvement compared with the pristine interface. However, an excessive number of defects can lead to a reduction in the thermal conductivity. These findings demonstrate that controlled defect engineering offers a tunable pathway to optimize interfacial heat transport in 2D heterostructures, providing valuable insights for thermal management in nanoscale devices.

Recently, diverse strategies have been exploited to engineer the magnetism of two-dimensional (2D) magnets to widen their application in spintronics. Here, we demonstrate the effect of manipulating optical phonons on the magnetism and Curie temperature (TC) of ferromagnetic CrI3. The first-principles calculations reveal that the anisotropy governed by dipole-dipole coupling exhibits negligible variations under 14 optical phonons, while the E4g (∼18.65%) and A11g (∼8.75%) modes can increase the magneto-crystalline anisotropic parameter (Kij) remarkably. Based on mean-field theory, we theoretically predict the Curie temperature of a CrI3 monolayer both in the absence and presence of phonon vibrations. Intriguingly, despite the E4g and A11g modes increasing Kij, they decrease TC by 3.76% and 16.10%, respectively. Conversely, the E3u and A22g modes enhance TC by 6.63% and 4.77%. The underlying mechanism is that E4g and A11g weaken the covalency and super-exchange coupling between Cr and I atoms, whereas the E3u and A22g modes strengthen them. Our work offers valuable theoretical insights for the application of 2D magnetic materials in spintronics.

Understanding polymer tribology at cryogenic temperatures is crucial for advancing extreme environment applications. This study employs molecular dynamics simulations to investigate the atomic-scale friction of polyether ether ketone (PEEK) sliding against copper at cryogenic temperature, comparing dry and ice-mediated lubrication. Results demonstrate that ice layer induces a remarkable transition from severe wear to an ultralow-wear state. Under dry conditions, significant plastic deformation, atomic pile-up, and temperature rise occur due to strong adhesion. In contrast, ice lubrication confines shear strain, suppresses plastic flow, maintains thermal stability, and preserves polymer integrity through extended chain conformations and protected bond geometries. Energy analysis reveals a fundamental mechanistic shift: from mechanics-dominated dissipation with high dihedral strain in dry friction to thermodynamics-dominated regime governed by non-bonded interactions under ice lubrication. This work provides atomic-scale insights into ice-mediated polymer lubrication, offering valuable guidance for designing cryogenic tribological systems.

Atomistic molecular dynamics (MD) simulations reveal how aqueous lubrication drastically alters the nanotribological response of copper-polyethylene (Cu-PE) interfaces. Compared with dry sliding, hydrated contacts display roughly 50% lower friction forces, strongly suppressed low-frequency friction fluctuations, minimal plastic deformation, and dramatically reduced wear. Time-frequency analysis of the lateral friction force, combined with a detailed decomposition of kinetic and potential energy components, shows that the confined water film acts as a dynamic energy sink that absorbs shear energy and helps restore PE chain conformations before permanent damage occurs. This interfacial water-mediated protection underpins the superior longevity, operational reliability, and biomedical and industrial viability of polyethylene-based components exposed to moving contacts, and provides mechanistic guidance for lubrication-focused design strategies.

Catalytic activity is conventionally understood in terms of static electronic structure descriptors, with lattice vibrations treated as a passive background. Here we show that intrinsic phonon modes can serve as an active and selective control knob for catalytic reactivity in 2D materials. Using density functional theory, we demonstrate that mode-specific lattice excitations in transition metal dichalcogenides dynamically modulate their electronic structure, inducing direct-indirect bandgap transitions and substantial bandgap renormalization. In Janus WSSe, excitation of the A1 2 mode reduces the bandgap to 0.93 eV, significantly enhancing carrier transport. More importantly, these phonon-induced lattice distortions systematically tune adsorption energetics and reaction pathways. Using the oxygen evolution reaction as a model system, we find that phonon activation lowers the overpotential by up to 17%, arising from weakened adsorption of key intermediates. Crystal orbital Hamilton population and p-band center analyses reveal that this effect originates from phonon-driven modulation of orbital hybridization and bonding strength. Our results establish a dynamic, mode-selective paradigm for controlling catalytic processes via intrinsic lattice degrees of freedom, opening a route toward phonon-engineered electrocatalysis beyond static materials design.

Thermal transport across interfaces is essential for optimizing the performance of two-dimensional heterostructures in nanoscale thermal management. Here, we explore the interfacial thermal conductance (ITC) of ultraflexible Janus MoSSe-WS2/WSe2 lateral heterostructures through nonequilibrium molecular dynamics simulations. By constructing heterostructures with different orientations and atomic configurations, we demonstrate that ITC is highly sensitive to the interfacial atomic arrangements, strain, temperature, and vacancy distribution. A distinct nonmonotonic dependence of ITC on strain is uncovered, primarily influenced by curvature-induced phonon scattering and anharmonic effects. Phonon wave packet simulations elucidate the frequency-dependent transmission behavior across the heterointerface, highlighting a significant suppression of high-frequency phonon transport. Moreover, vacancies in the transition metal layer can exert a more pronounced impact on ITC compared to those in the chalcogen layers. Our findings elucidate the microscopic mechanisms underlying thermal transport in Janus-based heterostructures and offer design guidelines for their applications in thermoelectric and heat dissipation technologies.

The broken mirror symmetry in Janus SMoSe and SWSe monolayers induces novel properties for photocatalytic, thermoelectric and photocatalytic devices. Interlayer coupling is critical in van der Waals (vdW) heterostructure for quantum transport and polaritonics. We investigate Janus SMoSe/SWSe vdW heterostructures with three stacking interfaces: S-S, S-Se, and Se-Se. The S-Se SMoSe/SWSe vdW heterostructure with lowest symmetry exhibits ultralow frequencies of in-plane shear (1.94 cm- 1) and out-of-plane breathing (4.47 cm- 1) modes due to weaker interlayer vdW restoring forces and a significant intrinsic vertical dipole moment. The reduced restoring forces are caused by the critical charge transfer across the vdW interface. Thus, the larger interlayer spacing in the S-Se SMoSe/SWSe heterostructure results in the suppressed vdW interlayer coupling for ultralow phonon frequencies. These findings advance understanding of tuning vdW coupling in polar Janus SMoSe/SWSe heterostructures by stacking engineering, providing theoretical insights for designing tunable nanoelectronic devices.

This work investigates the mechanical properties of a silicon carbide (SiC) nanophononic heterostructure (NPH) tuned by temperatures and pore geometries, using molecular dynamics (MD) simulations in conjunction with the machine learning method. The SiC NPH, constructed with pure SiC and phononic crystal pores, exhibits temperature-dependent fracture behavior, showing a decrease in mechanical strength decreasing as the temperature increases from 50 to 500 K. The fracture strength and strain are markedly influenced by pore size, with a particular emphasis on pore length, whereas pore width exerts a negligible influence. In addition, armchair interfaces can cause a higher mechanical strength compared with zigzag interfaces. The presence of larger phononic pores amplifies stress concentrations and thermal effects, consequently resulting in more significant reductions in mechanical performance. More importantly, a random forest model has been developed to accurately predict fracture characteristics of the SiC NPH, achieving a high degree of precision (R 2 = 0.99) and offering a 600-fold increase in computational speed compared to traditional MD methods. These findings provide valuable insights for designing robust SiC-based nanodevices with tunable mechanical properties.

Herein, we propose a new GaN/MoSi2P4 van der Waals (vdWs) heterostructure constructed by vertically stacking GaN and MoSi2P4 monolayers. Its electronic, optical, and photocatalytic properties are explored via DFT+G0W0+BSE calculations. The calculated binding energy and phonon spectrum demonstrated the material's high stabilities. The projected band structure of GaN/MoSi2P4 suggests that it has a desirable direct bandgap and displays type-I band alignment. It also exhibits a particularly large absorption coefficient for visible and near-infrared light while considering electron-hole interactions. Intriguingly, a small biaxial tensile strain of +1% can transform the band alignment to type-II using a direct Z-scheme mechanism for water splitting. The Z-scheme optimizes redox ability, thus perfectly engulfing the redox potentials of water and showing excellent photocatalytic activity in different layers. Our findings indicate that the GaN/MoSi2P4 vdWs heterostructure is a promising optoelectronic and photocatalytic material.

Although the manipulation of physical properties is common in applications of two-dimension (2D) materials, it is rare to tailor electronic properties by phonon vibration. In this article, we tailor the electronic band structure of Cr2TiC2FCl monolayer from indirect semiconducting state to metallic state by phonon modes ( A 1 2 , A 1 5 , and A 1 6 mode) with the Raman and infrared active. The A 1 4 mode makes Cr2TiC2FCl monolayer become direct semiconductor with a little gap, which can elevate the optical absorption efficiency of Cr2TiC2FCl monolayer, especially in the visible region. Meanwhile, both the conduction band minimum (CBM) and valence band maximum (VBM) are contributed by the spin-down channel; so, the electron hopping between VBM and CBM also does not need the participation of spin flipping and chiral phonon in Cr2TiC2FCl monolayer under the A 1 4 mode. These results are significant for the application of 2D materials in the semiconductor laser, solar cell, and photodetector.

In this work, we systematically investigate the cross-plane thermal conductivity in stacked diamane via molecular dynamics simulations, focusing on the effects of stacking orientation, external pressure, interlayer coupling strength, and twist angle. By combining spectral heat current decomposition and spectral energy density analysis, we identify high-frequency optical phonons within 10-15 THz as the dominant heat carriers across interfaces-a selectivity arising from interfacial hydrogen termination that strengthens the coupling of these modes. Their lifetimes and coupling strengths are highly sensitive to structural configuration and mechanical modulation. Our results reveal that parallel stacking, increased pressure, and stronger interlayer coupling significantly enhance thermal conductivity by stabilizing optical modes and suppressing phonon scattering. In contrast, increasing the twist angle introduces structural incommensurability, which reduces phonon lifetimes and leads to substantial suppression of thermal transport. These findings underscore the pivotal role of optical phonons in governing interfacial thermal transport as well as establish an optimal strategy for engineering thermal conductivity in 2D vdW materials.

Janus transition metal dichalcogenides (TMDs) exhibit exceptional electronic, optical, and catalytic properties due to their unique asymmetric structures. The article systematically investigates the stability of Janus MoSSe with typical vacancy defects using first‐principles calculations. The results reveal that the Gibbs free energy for the hydrogen evolution reaction (HER) is significantly reduced to ≈0.5 eV, lower than that of pristine MoSSe and conventional MoS 2 monolayers. Notably, the application of external strain further enhances the HER performance of defect‐engineered Janus MoSSe. This improvement is attributed to the adaptive release of concentrated strain by dangling bonds at the defect region, resulting in distinct tunable patterns. The findings elucidate the underlying mechanism behind the enhanced HER performance of MoSSe through strain engineering, providing theoretical support for the optimal design of efficient HER catalysts based on defective Janus TMDs.

Janus two-dimensional materials including transition metal dichalcogenides, transition metal carbides and carbonitrides, and metal-organic frameworks, exhibit unique electronic, optical, piezoelectric, and dielectric properties due to their asymmetric atomic structures, making them promising candidates for nanoelectronics, energy storage conversion and storage, and biomedical applications. This review comprehensively highlights the unique properties and typical applications of Janus two-dimensional materials and their van der Waals heterostructures. We explore the fundamental mechanisms underlying their electronic and optoelectronic properties, including band structures and light absorption. Strategies for enhancing their performance are discussed, providing a framework for addressing future research challenges. This comprehensive review integrates theoretical insights, synthesis techniques, and diverse applications, emphasizing the potential of Janus twodimensional materials to revolutionize hydrogen production and other technological domains. We conclude by summarizing current advancements and future directions, offering inspiration for continued innovation in two-dimensional materials applications.

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have demonstrated high catalytic activity for the hydrogen evolution reaction (HER). However, these materials usually form with wrinkles instead of being perfectly planar, which induce internal strain, alter the electronic properties and consequently influence the catalytic performance. The impact of wrinkles on the HER catalytic activity of 2D TMDs is essential to understanding the structure-property relationship under real conditions and requires specific investigations. By employing first-principles calculations and following the Euler-Bernoulli beam theory, we systematically explore the effect of intrinsic wrinkles of the MoSSe/WSSe lateral heterostructure on their electronic structure and catalytic performance for the HER. We demonstrate that the polarity of the MoSSe/WSSe heterostructure is reduced with a wrinkled configuration. We reveal the high HER activity of the wrinkled MoSSe/WSSe heterostructure by showing a low overpotential of -0.18 V, which can be favorably tuned by applying external strain because of its high strength and good elasticity. The strain-dependent HER performance is rationalized by the linear correlation between the applied strain and the reaction energy. Our investigation reveals the role of intrinsic wrinkles in determining the mechanical and electronic properties and catalytic performance of 2D TMDs, and sheds new light on the rational design of TMD heterostructures for effective HER by taking advantage of wrinkled morphologies.

The electrochemical hydrogenation of furfural (FF) to furfuryl alcohol (FA) represents a sustainable strategy for upgrading biomass-derived feedstocks, where synergistic Cu-0/Cu+ sites serve as key active centers. However, elucidating the underlying mechanism and optimizing catalytic performance remain challenging due to the difficulty in precisely tuning the Cu-0/Cu+ ratio. Herein, we report a facet-engineering approach to modulate the surface reconstruction of Cu2O, enabling the controlled regulation of Cu oxidation states and enhanced FF-to-FA conversion. Finite element simulations and experimental characterizations reveal that morphological evolution from cubic to cuboctahedral and to octahedral Cu2O nanoparticles progressively intensifies local electric fields, promoting in situ Cu+ reduction and adjusting the Cu-0/Cu+ ratio. Among these, the cuboctahedral Cu2O-derived catalyst exhibits the highest FA faradic efficiency (FE) and conversion rate (72.5% and 100.0%), outperforming its cubic (56.5% and 79.0%) and octahedral (59.5% and 85.6%) counterparts. Density functional theory (DFT) calculations corroborated by in situ electrochemical impedance spectroscopy (EIS) reveal that a moderate Cu-0/Cu+ ratio optimally lowers the desorption energy of the key intermediate (FCH2OH*) and accelerates interfacial charge transfer, thereby enhancing the overall catalytic performance. This work establishes facet engineering as an effective strategy for tailoring Cu-0/Cu+ sites, advancing the rational design of biomass conversion electrocatalysts.