First-principles calculations were used to investigate the effects of Si content and pressure on the phase structures and mechanical properties of FeCoNiCuSi _x B_{1 - x} (x = 0, 0.25, 0.5, 0.75, 1) high entropy alloys. Structural stability was evaluated by calculating relevant parameters based on the multicomponent phase formation criteria for high entropy alloys. The results show that the alloys exhibit a multiphase structure consisting of an FCC solid solution and intermetallic compounds. With increasing Si content, the FeCoNiCuSi _x B_{1 - x} high entropy alloys exhibit increased lattice constants, decreased density, and reduced elastic moduli (B, G, and E). The B/G ratio and Poisson's ratio initially decrease and then increase, indicating that the ductility initially decreases and subsequently improves with increasing Si content, while high Si contents reduce the tendency toward brittle fracture. Heat of formation analysis reveals that Si enhances the thermodynamic stability of the alloy system. Under pressures ranging from 0 to 100 GPa, FeCoNiCuSi_0.5B_0.5 high entropy alloy exhibits a reduced lattice constant, increased density, enhanced deformation resistance, and weakened pressure-induced elastic anisotropy approaching isotropic behavior. The yield strength increases with increasing pressure, and the alloy exhibits excellent comprehensive mechanical properties.

The composites C_f/ZrB₂-SiC and C_f/ZrB₂-SiBCN with high ZrB₂ content were prepared via a combined method of slurry infiltration (SI) and precursor infiltration pyrolysis (PIP), accordingly their densities are 2.73 g/cm³ and 2.70 g/cm³ respectively, and the ZrB₂ content exceeding 25% (volume fraction). The effect of different precursors on the oxidation and ablation behavior of the composites was investigated, aiming to address issues such as the low reusable temperature and insufficient understanding of ablation behavior for carbon fiber-reinforced ultra-high temperature ceramic matrix composites. The results showed that after nine oxidation cycles at 1200 °C, the mass loss rates of C_f/ZrB₂-SiBCN and C_f/ZrB₂-SiC were comparable, at 3.69% and 3.59%, respectively. However, after the same number of oxidation cycles at 1400 ^oC, the mass loss rate of C_f/ZrB₂-SiBCN was significantly higher than that of C_f/ZrB₂-SiC, reaching 5.05%. This is primarily attributed to the volatilization of B- and N-gaseous compounds from the oxidation products of SiBCN at higher temperatures. After nine cycles of oxyacetylene flame ablation at 1800 ^oC and 2100 ^oC for a single duration of 300 s, the mass loss rates of C_f/ZrB₂-SiBCN were 1.29% and 1.93%, respectively, which are significantly lower than those of C_f/ZrB₂-SiC composites. This improvement is mainly due to the higher density of C_f/ZrB₂-SiBCN and the better healing ability of the glass phase formed during cyclic ablation, which reduces mechanical erosion caused by gas flow and mitigates subsurface crack propagation.

A novel heterojunction electrocatalyst of NiFe-layered double hydroxide/Co, La doped CeO₂ was prepared by electrodepositing ultrathin NiFe-LDH nanosheets onto a Co, La co-doped CeO₂ (Co, La-CeO₂) support on copper foam (CF) according to the "lattice-interface synergistic regulation" strategy of our group. The support of Co, La co-doped CeO₂ on CF was first synthesized via a one-pot hydrothermal method, while the controllable lattice strain and abundant oxygen vacancies (Oᵥ) were introduced, which may significantly enhance the intrinsic electronic conductivity and structural stability of the support. Furthermore, the strong interfacial coupling between NiFe-LDH and Co, La co-doped CeO₂ may facilitate the charge transfer and optimize the adsorption of oxygen-containing intermediates. As a result, the NiFe-LDH/Co, La co-doped CeO₂/CF composite exhibits superior performance of oxygen evolution reaction in 1.0 mol/L KOH, requiring an overpotential of only 230 mV to reach 50 mA·cm^-2 with a Tafel slope of 74.65 mV·dec^-1. It also retains 97.14% of its initial current density after 50 h of continuous operation. This study highlights the importance of lattice doping and interfacial synergy, providing a generalizable design framework for high-efficiency non-noble metal electrocatalysts for oxygen evolution reaction.

The high-cycle fatigue (HCF) damage behavior of a bainite-martensite dual-phase steel was studied in terms of the relevant mechanism of cyclic softening emerged by cyclic tension-compression loading. It is found that, inclusions in the steel are predominantly complex inclusions consisting of hard oxide cores encapsulated by MnS shells, from which fatigue cracks preferentially initiate. Statistical analysis reveals that, under a cyclic loading condition with stress ratio of R = -1, the fatigue lives of most specimens are located into two distinct regimes, approximately 10⁵ and 10⁷ cycles, exhibiting a characteristic of pronounced bimodal distribution. Fractographic analysis combined with finite element method (FEM) simulations demonstrates that significant stress concentration arises at the interface between the MnS shell and the steel matrix. Such interfacial regions, particularly those located near the specimen surface, are more susceptible to fatigue crack initiation. Consequently, both the structural characteristics and spatial distribution of large non-metallic inclusions play a dominant role in the bimodal fatigue life behavior of this material.

Noise pollution has been a potential hazard affecting human health. In this paper, a sound-absorbing material based on modified cellulose composite aerogel (MCA) was prepared with cellulose aerogel serving as the matrix, carbon fibers and MoSi₂ particulates as doping material. Carbon fibers can intercalate in between the layers of carboxymethyl cellulose to construct rigid fiber scaffolds, while MoSi₂ particulates disperse on the layers of carboxymethyl cellulose to form a large number of heterogeneous interfaces. This not only improves the mechanical properties of the material but also broadens its sound-absorbing frequency range. The prepared MCA was characterized by means of universal testing machine and two-microphone impedance tube etc. The results show that the MCA maintains a low density (< 0.06 g/cm³) and high porosity (> 97.60%), while its compressive stress at 70% strain reaches 0.131 MPa, with a 104.7% increasement compared with the unmodified aerogel. The MCA has a sound-absorbing coefficient of over 0.7 in the frequency range of 1000-5500 Hz, with a maximum value of 0.99. In particular, its sound-absorbing coefficient in the mid-frequency range (~1250 Hz) increases from 0.56 to 0.8, representing an increase rate of 42.9% in contrast to the plain aerogel.

Biomass-derived carbon materials are promising electrode materials for new energy storage devices due to their wide availability, low cost, and tunable structures. However, conventional synthesis methods are often complex, energy-intensive, and time-consuming. This study reports a molten salt-assisted flash Joule heating strategy for the rapid and efficient preparation of porous carbon from cellulose. In contrast to carbon derived from conventional tube furnace pyrolysis, the flash Joule heated carbon possesses a hierarchical porous structure, which facilitates charge storage and rapid ion transport. Furthermore, it exhibits a higher concentration of oxygen functional groups and defects. Electrochemical analysis in a three-electrode system confirmed that the flash Joule heated carbon delivers a superior specific capacity and enhanced reaction kinetics. To demonstrate its practical application potential, symmetric supercapacitors and zinc-ion hybrid capacitors were assembled using this material, both of which exhibited enhanced electrochemical performance. This work highlights the great potential of flash Joule heating as a universal strategy for converting biomass into high-value carbon materials for diverse energy storage applications.

Herein, Ho³⁺/Yb³⁺ co-doped Si₃N₄ branched nanowires (Si₃N₄:Ho³⁺/Yb³⁺) were fabricated via plasma arc technique, and then characterized by means of X-ray diffraction, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Results indicate that the branched nanowires comprise a main trunk with multiple branches growing in parallel along both sides, while the Ho³⁺ and Yb³⁺ ions were successfully incorporated into the branched nanowire structure of Si₃N₄. Under 980 nm laser excitation, the Si₃N₄:Ho³⁺/Yb³⁺ branched nanowires exhibit three distinct up-conversion (UC) luminescence peaks: green emission at 540 nm corresponds to the (⁵F₄,⁵S₂→⁵I₈) transition of Ho³⁺; while the red emissions at 660 nm and 756 nm are attributed to the (⁵F₅→⁵I₈) and (⁵F₄→⁵I₇) transitions, respectively. Based on the UC emission intensity ratio and decay lifetime, the optical temperature sensing performance of the Ho³⁺/Yb³⁺ co-doped Si₃N₄ branched nanowires was systematically investigated over the temperature range of 298-558 K. It follows that the method for temperature measurement based on the I₅₄₀/I₆₆₀ intensity ratio achieves a maximum relative sensitivity of 2.13% K^-1. Meanwhile, the relative sensitivity based on the decay lifetime of the 540 nm emission peak reaches 1.10% K^-1. The above findings prospect the great potential in application of the Ho³⁺/Yb³⁺ co-doped Si₃N₄ branched nanowires for optoelectronic devices, biomedicine, high-precision temperature sensing, and laser technologies.

Composites with W particles as the reinforcement phase and Ti₇Zr_1.5VAl_0.5 high-entropy alloy (HEA) as the matrix were fabricated via hot isostatic pressing (HIP) sintering. The effect of W content on the microstructure, densification behavior, and room-temperature compression properties of the composites were systematically investigated using X-ray diffraction, scanning electron microscopy and electronic universal testing machine. The results indicated that the composite with W:Ti₇Zr_1.5VAl_0.5 of 1:1 (in molar ratio) exhibited the optimal comprehansive mechanical properties, achieving a yield strength of 1146 MPa and a plastic strain of 36%. As the molar ratio of W to Ti₇Zr_1.5VAl_0.5 increased, both the yield strength and plasticity generally showed a declining trend. At a molar ratio of 2:1, the yield strength and plastic strain decreased to 892 MPa and 16%, respectively. Concurrently, the dominant fracture mechanism transitioned from ductile to brittle with the increasing W content. The deterioration in mechanical performance may be attributed to several factors. First, the significant density difference between W particles and the HEA matrix promoted gravity segregation and particle agglomeration, which weakened the dispersion-strengthening effect. In addition, a higher W content led to an increased number of inherent pores on the W particle surfaces; these pores could not fully be eliminated during sintering and consequently reduced the overall densification of the composite. Furthermore, under external loading, such micro-pores could act as stress-concentration sites, facilitating the initiation and propagation of micro-cracks and ultimately inducing interfacial debonding between the matrix and the W particles, which resulted in fracture.