Search Results (1,127)

Lattice structures find broad application in aerospace, automotive, biomedical, and energy systems owing to their exceptional structural stability. These systems typically exhibit complex internal couplings that facilitate vibration propagation across the entire network. The primary objective of this study is to achieve total decoupling of 2D lattice vibration system, which involves eliminating all inter-subsystem interactions while preserving spectrum. Building upon prior research, we develop structure-preserving isospectral transformation flow (SPITF) framework to address this challenge. Two principle results are established: first, the equations of motion are systematically derived for lattice vibration systems; second, total decoupling is successfully realized for such systems. Numerical experiments validate the decoupling capability of lattice vibration systems. Full article

Molecular dynamics (MD) can dynamically reveal the structural evolution and mechanical response of Zirconium (Zr) at the atomic scale under complex service conditions such as high temperature, stress, and irradiation. However, traditional empirical potentials are limited by their fixed function forms and parameters, making it difficult to accurately describe the multi-body interactions of Zr under conditions such as multi-phase structures and strong nonlinear deformation, thereby limiting the accuracy and generalization ability of simulation results. This paper combines high-throughput first-principles calculations (DFT) with the machine learning method to develop the Deep Potential (DP) for Zr. The developed DP of Zr was verified by performing molecular dynamic simulations on lattice constants, surface energies, grain boundary energies, melting point, elastic constants, and tensile responses. The results show that the DP model achieves high consistency with DFT in predicting multiple key physical properties, such as lattice constants and melting point. Also, it can accurately capture atomic migration, local structural evolution, and crystal structural transformations of Zr under thermal excitation. In addition, the DP model can accurately capture plastic deformation and stress softening behavior in Zr under large strains, reproducing the characteristics of yielding and structural rearrangement during tensile loading, as well as the stress-induced phase transition of Zr from HCP to FCC, demonstrating its strong physical fidelity and numerical stability. Full article

This study investigates the influence of strut cross-sectional geometry and orientation on the crashworthiness of octet truss lattice structures produced via Multi Jet Fusion (MJF) using Polyamide 12 (PA12) material. All lattice configurations were designed and printed at a constant relative density of approximately 30%, ensuring equal mass and material usage across geometries. Quasi-static compression tests were conducted on lattices featuring circular, elliptical, rectangular, and square struts, with the latter two also evaluated at 0° and 90° orientations relative to the loading direction. Energy absorption (EA), specific energy absorption (SEA), crush force efficiency (CFE), and mean plateau stress metrics were employed to evaluate the structural energy absorption efficiency. The results highlight that strut geometry and orientation significantly alter mechanical behavior due to differences in moments of inertia. The circular strut lattice, used as the reference configuration, achieved an SEA of 0.79 J/g. Among the tested designs, the elliptical lattice exhibited the most pronounced variation: the non-rotated version showed the lowest SEA (0.63 J/g, ~20% lower than the reference), whereas the 90° rotated version yielded the highest SEA (0.92 J/g, ~16% higher). Rectangular struts displayed a similar trend, with rotated specimens outperforming their non-rotated counterparts. Square struts, however, showed negligible differences between orientations, as their rotational inertia remained constant. Overall, the findings demonstrate that optimizing strut cross-sections can enhance crashworthiness by improving energy dissipation and stabilizing deformation mechanisms under compressive loading. The rotated elliptical cross-section emerged as the most efficient configuration, offering superior SEA and crush stress efficiency. The findings highlight that cross-sectional design and orientation provide an effective mechanism for tuning mechanical performance in lightweight lattice materials without altering overall density or topology. These insights emphasize the potential of geometric tailoring in lattice design to meet safety and lightweight requirements in transportation, defense and biomedical applications. Full article

Wide-bandgap (WBG) perovskite solar cells (PSCs) are critical for high-efficiency tandem photovoltaic devices, but their practical application is severely limited by phase separation and poor film quality. To address these challenges, this study proposes a dual-additive passivation strategy using potassium thiocyanate (KSCN) and potassium chloride (KCl) to synergistically optimize the crystallinity and defect state of WBG perovskite films. The selection of KSCN/KCl is based on their complementary functionalities: K⁺ ions occupy lattice vacancies to suppress ion migration, Cl⁻ ions promote oriented crystal growth, and SCN⁻ ions passivate surface defects via Lewis acid-base interactions. A series of KSCN/KCl concentrations (relative to Pb) were tested, and the effects of dual additives on film properties and device performance were systematically characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), space-charge-limited current (SCLC), current-voltage (J-V), and external quantum efficiency (EQE) measurements. Results show that the dual additives significantly enhance film crystallinity (average grain size increased by 27.0% vs. control), reduce surface roughness (from 86.50 nm to 24.06 nm), and passivate defects-suppressing non-radiative recombination and increasing electrical conductivity. For WBG PSCs, the champion device with KSCN (0.5 mol%) + KCl (1 mol%) exhibits a power conversion efficiency (PCE) of 16.85%, representing a 19.4% improvement over the control (14.11%), along with enhanced open-circuit voltage (Voc: +2.8%), short-circuit current density (Jsc: +6.7%), and fill factor (FF: +8.9%). Maximum power point (MPP) tracking confirms superior operational stability under illumination. This dual-inorganic-additive strategy provides a generalizable approach for the rational design of stable, high-efficiency WBG perovskite films. Full article

Owing to the inherent safety, environmental friendliness, and high theoretical capacity (820 mAh g⁻¹) of zinc metal, aqueous zinc-ion batteries (AZIBs) have emerged as up-and-coming alternatives to organic lithium-ion batteries. However, the insufficient electrochemically active sites, poor structural stability, and severe interfacial side reactions of cathode materials have always been key challenges, restricting battery gravimetric energy density and cycling stability. This article systematically reviews current mainstream AZIB cathode material systems, encompassing layered manganese- and vanadium-based metal oxides, Prussian blue analogs, and emerging organic polymers. It focuses on analyzing the energy storage mechanisms of different material systems and their structural evolution during Zn²⁺ (de)intercalation. Furthermore, mechanisms of innovative strategies for improving cathodes are thoroughly examined here, such as nanostructure engineering, lattice doping control, and surface coating modification, to address common issues like structural degradation, manganese/vanadium dissolution, and interface passivation. Finally, this article proposes future research directions: utilizing multi-scale in situ characterization to elucidate actual reaction pathways, constructing artificial interface layers to suppress side reactions, and optimizing full-cell design. This review provides a new perspective for developing practical AZIBs with high specific energy and long lifespans. Full article

Coplanar tridentate nitrogen-donor ligands have been extensively employed to stabilize transition metal complexes by chelation. Some complexes exhibit interesting structures and photoluminescent properties. In this work, 2,6-bis(5-isopropyl-1H-pyrazole-3-yl)pyridine (denoted as L), its iron(II) and manganese(II) dichlorido complexes, and its bis-chelate iron(II) complexes, viz. [FeCl₂(L)]·2(MeOH) and [MnCl₂(L)]·2(MeOH), and [Fe(L)₂](PF₆) ·5(thf), respectively, were synthesized and characterized by single-crystal X-ray structural analysis. These solid-state structures contained N–H donors that formed hydrogen bonds with the coordinated halogenide ions and lattice solvent molecules, methanol or tetrahydrofuran. The iron(II) and manganese(II) dichlorido complexes [FeCl₂(L)]·2(MeOH) and [MnCl₂(L)]·2(MeOH) displayed distorted trigonal pyramidal structures in the solid state. However, [FeCl₂(L)]·2(MeOH) was not stable in methanol and formed the bis-chelate iron(II) complex [Fe(L)₂](FeCl₄). Therefore, the bis-chelate iron(II) complex [Fe(L)₂](PF₆)·5(thf) was also synthesized and structurally and spectroscopically authenticated. Full article

Human immunodeficiency virus type 2 (HIV-2) is a lentivirus closely related to HIV-1 but exhibits distinct molecular and clinical features that influence viral infectivity and efficacy of antiretroviral therapy. The HIV capsid is a critical structural component with multifaceted roles during infection and mediates some of the observed divergence between HIV-1 and HIV-2. Unlike HIV-1, study of the HIV-2 capsid is limited and standard protocols for the in vitro assembly of HIV-1 capsid protein (CA) lattice structures have not been successfully translated to the HIV-2 context. This work identifies effective approaches for the assembly of the HIV-2 CA lattice and leverages this to biochemically characterize HIV-2 CA assemblies and mutant phenotypes. Our findings elaborate on the sensitivity of HIV-2 CA to chemical conditions and reveal that it assembles into a more varied spectrum of particle morphologies compared to HIV-1. Utilizing these assemblies, we tested the hypothesis that HIV-1 and HIV-2 employ divergent mechanisms to stabilize CA oligomer forms and investigate the effects of non-conserved substitutions at the CA inter-protomer interfaces. This work advances our understanding of the key biochemical determinants of HIV-2 CA assembly that are distinct from HIV-1 and may contribute to their divergent virological properties. Full article

Under extreme operating conditions, the internal lubricating flow field of high-speed gear transmission systems exhibits a transient oil–gas multiphase flow, predominantly governed by cavitation-induced phase transitions and turbulent shear. This phenomenon involves complex mechanisms of nonlinear multi-physical coupling and energy dissipation. Traditional lubrication theories and single-phase flow simplified models show significant limitations in capturing microsecond-scale flow features, dynamic interface evolution, and turbulence modulation mechanisms. To address these challenges, this study developed a cross-scale coupled numerical framework based on the Lattice Boltzmann method and large eddy simulation (LBM-LES). By incorporating an adaptive time relaxation algorithm, the framework effectively enhances the computational accuracy and stability for high-speed rotational flow fields, enabling the precise characterization of lubricant splashing, distribution, and its interaction with air. The research systematically reveals the spatiotemporal evolution characteristics of the internal flow field within the gearbox and focuses on analyzing the nonlinear regulatory effect of baffle geometric parameters on the system’s energy transport and dissipation characteristics. Numerical results indicate that the baffle structure significantly influences the spatial distribution of the vorticity field and turbulence intensity by reconstructing the shear layer topology. Low-profile baffles optimize the energy transfer pathway, effectively reducing the flow enthalpy, whereas excessively tall baffles induce strong secondary recirculation flows, exacerbating vortex-induced energy losses. Simultaneously, appropriately increasing the spacing between double baffles helps enhance global lubricant transport efficiency and suppresses unsteady dissipation caused by localized momentum accumulation. Furthermore, the geometrically optimized double-baffle configuration can achieve synergistic improvements in lubrication performance, oil film stability, and system energy efficiency by guiding the main shear flow and mitigating localized high-momentum impacts. This study provides crucial theoretical foundations and design guidelines for developing the next generation of theory-driven, energy-efficient lubrication design strategies for gear transmissions. Full article

To alleviate CaF₂ scaling on reverse osmosis membranes, polyepoxysuccinic acid (PESA) was modified with 2,5-dihydroxyterephthalic acid (DHTA) to obtain DHTA-PESA. Its structure and thermal stability were confirmed through characterization. Scale inhibition performance was evaluated using static and dynamic experiments. Results showed that in static tests, at a dosage of 200 mg/L, DHTA-PESA achieved a CaF₂ scale inhibition rate of nearly 100%, demonstrating Ca²⁺ chelation ability and the capacity to prolong crystallization induction time. In dynamic experiments, indicating superior CaF₂ dispersion performance and effective mitigation of membrane fouling. X-ray diffraction and scanning electron microscopy analysis revealed that DHTA-PESA induces irregular growth of CaF₂ crystals, disrupting their formation and altering crystal morphology. The primary scale inhibition mechanisms include dispersion, lattice distortion, and chelation. Full article

Ceramic matrix composites (CMCs) are extensively utilized in aero engines due to their high-temperature stability; however, they are prone to environmental corrosion at high temperatures, and environmental barrier coatings (EBCs) are necessary to resist oxidation and corrosion. Among various EBC materials, AlTaO₄ offers high cost-effectiveness and low thermal expansion coefficients (TECs), but its resistance to SiO₂ erosion and high-temperature stability remain unclear. We investigated the influences of SiO₂ additions on the structures and thermal properties of AlTaO₄; and AlTaO₄ mixtures containing 10 wt.% SiO₂ were kept at 1400 °C for 30–120 h. AlTaO₄ exhibited excellent high-temperature phase stability, and SiO₂ dissolved into AlTaO₄ to generate a solid solution. XRD Rietveld refinement was employed to confirm the position of Si in the lattices, while SEM and EDS characterizations demonstrated the homogeneous distribution of Si, Al, and Ta elements. At 1200 °C, the TECs of SiO₂-AlTaO₄ (4.65 × 10⁻⁶ K⁻¹) were close to those of SiC (4.5–5.5 × 10⁻⁶ K⁻¹). Additionally, the addition of SiO₂ could reduce TECs of AlTaO₄, a feature that helped alleviate the interface thermal stress between AlTaO₄ and the Si bond coat in the EBC systems. At 900 °C, the thermal conductivity was reduced by 26.9% compared to that of AlTaO₄, and the lowest value was 1.65 W·m⁻¹·K⁻¹. Accordingly, SiO₂ will enter the lattices of AlTaO₄ after heat treatments at 1400 °C, and SiO₂ additions will reduce the thermal conductivity and TECs of AlTaO₄, which is beneficial for its EBC applications. Full article

The structure, chemical composition, thermal stability, and abuse responses of cathode materials are critical to the safety and economy of lithium-ion batteries (LIBs). This review systematically summarizes advances in research on how cathode materials influence LIB thermal runaway (TR) behavior. It analyzes the oxygen release from cathodes in TR mechanisms and the hazards of such oxygen generation during TR, expounds on how differences in cathode structure, chemical composition, and thermal stability affect TR behavior, and summarizes the thermal characteristics of LIBs with different cathodes under mechanical, electrical, and thermal abuse. Results indicate that oxygen released from cathode decomposition during TR oxidizes electrolytes, releasing substantial heat and gas and causing more severe TR hazards. Structural instability of cathodes leads to accelerated release of lattice oxygen, speeding up TR initiation. Chemical composition regulates thermal stability, phase transition pathways, and gas generation rates during TR, while elemental ratios affect the ease of TR triggering. Cathodes with poor thermal stability have lower thermal decomposition onset temperatures, making TR more likely to occur and intensifying reaction severity. All three abuse types trigger inherent risks of cathodes, inducing TR and significantly increasing its occurrence probability. Differences in intrinsic properties further extend to the system level, also influencing thermal runaway propagation and fire dynamics at the module level. Future research focusing on the intrinsic properties of cathodes and external abuse is of great significance for addressing LIB TR behavior. Full article

Supercapacitors (SCs) are widely acknowledged for their high-power density as energy storage devices; designing electrode materials with both high efficiency and exceptional energy density remains a significant challenge. In this study, a flower-like iron-doped molybdenum sulfide on graphene nanosheets (FMS/G) was synthesized through a simple, efficient, and scalable solvothermal approach. The FMS/G composite demonstrated exceptional performance when employed as both positive and negative electrodes, owing to the effective incorporation of iron into the MoS₂ crystal lattice. This doping induces defects and facilitates abundant redox reactions, ultimately boosting electrochemical performance. The FMS/G composite demonstrates an ultrahigh specific capacitance of 931 F g⁻¹ at 1 A g⁻¹, along with excellent rate capability, retaining 582 F g⁻¹ at 20 A g⁻¹. It also exhibits remarkable cycling stability, maintaining 90.5% of its initial capacitance after 10,000 cycles. Furthermore, the assembled FMS/G-3//FMS/G-3 supercapacitor device achieves a superior energy density of 64.7 Wh kg⁻¹ at a power density of 0.8 kW kg⁻¹ with outstanding cycling stability, retaining 92% of its capacitance after 10,000 cycles. The remarkable capabilities of the flower-like FMS/G composite underscore its noteworthy potential for promoting effective energy storage systems. Full article

High-entropy alloys (HEAs) are highly concentrated, multicomponent alloys that have received significant attention due to their superior properties compared to conventional alloys. The mechanical properties and hardness are interrelated, and it is widely known that the hardness of HEAs depends on the principal alloying elements and their composition. Therefore, the desired hardness prediction to develop new HEAs is more interesting. However, the relationship of these compositions with the HEA hardness is very complex and nonlinear. In this study, we develop an artificial neural network (ANN) model using experimental data sets (535). The compositional elements—Al, Co, Cr, Cu, Mn, Ni, Fe, W, Mo, and Ti—are considered input parameters, and hardness is considered as an output parameter. The developed model shows excellent correlation coefficients (Adj R2) of 99.84% and 99.3% for training and testing data sets, respectively. We developed a user-friendly graphical interface for the model. The developed model was used to understand the effect of alloying elements on hardness. It was identified that the Al, Cr, and Mn were found to significantly enhance hardness by promoting the formation and stabilization of BCC and B2 phases, which are inherently harder due to limited active slip systems. In contrast, elements such as Co, Cu, Fe, and Ni led to a reduction in hardness, primarily due to their role in stabilizing the ductile FCC phase. The addition of W markedly increased the hardness by inducing severe lattice distortion and promoting the formation of hard intermetallic compounds. Full article

To address the synergistic degradation mechanisms in engineering service environments, we propose a boron microalloying strategy to enhance the multifunctional surface performance of AlCoCrFeNiMo-based high-entropy alloys. AlCoCrFeNiMoTiBx coatings (x = 0, 0.5, 1, and 1.5) were fabricated on Q235 steel substrates using laser cladding. The microstructure of the coatings was characterized using scanning electron microscope (SEM) and energy dispersive spectrometer (EDS), while their wear and corrosion resistance were evaluated through tribological and electrochemical tests. The key findings indicate that boron addition preserves the original body-centered cubic (BCC) and σ phases in the coating while promoting the in situ formation of TiB₂, leading to lattice distortion. With increasing B content, the BCC phase becomes refined, and both the fraction and size of TiB₂ particles increase. Boron incorporation improves the coating’s microhardness and wear resistance, with the highest wear resistance achieved at x = 1, where abrasive and oxidative wear predominate. At lower content (x = 0.5), B enhances the stability of the passive film and thereby improves corrosion resistance. In contrast, excessive formation of large TiB₂ particles introduces defects into the passive film, accelerating its degradation. Full article

Multiple-Q magnetic states encompass a broad class of noncollinear and noncoplanar spin textures generated by the superposition of spin density waves. In this study, we theoretically explore the emergence of vortex crystals formed by multiple-Q spin density waves on a two-dimensional triangular lattice with $D_{3\mathrm{h}}$ point group symmetry. Using simulated annealing applied to an effective spin model, we demonstrate that the synergy among the easy-plane single-ion anisotropy, the biquadratic interaction, and the out-of-plane Dzyaloshinsky–Moriya interaction defined in momentum space can give rise to a variety of double-Q and triple-Q vortex crystals. We further examine the role of easy-plane single-ion anisotropy in triple-Q vortex crystals and show that weakening the anisotropy drives topological transitions into skyrmion crystals with skyrmion numbers $\pm 1$ and $\pm 2$. The influence of an external magnetic field is also analyzed, revealing a field-induced phase transition from vortex crystals to single-Q conical spirals. These findings highlight the crucial role of out-of-plane Dzyaloshinskii–Moriya interactions in stabilizing unconventional vortex crystals, which cannot be realized in systems with purely polar or chiral symmetries. Full article