While noble metal-based catalysts remain the most effective for the four-electron oxygen reduction reaction (ORR), nitrogen-doped carbon materials are promising non-metal alternatives. However, atomic-level modulation of pyridinic-N sites to rival Pt-based ORR activity remains a fundamental challenge. To address this, we developed a novel "defect-guided in situ atomic substitution" strategy. Using highly fluorinated graphene as a precursor, we achieved synchronous defluorination, graphitization, and precise nitrogen doping through a one-step thermochemical process. CF bond cleavage generates transient carbon vacancies that serve as anchoring sites, constructing a catalytic surface rich in pyridinic nitrogen. The resulting nitrogen-doped graphene catalyst (PN-G) exhibits outstanding bifunctional activity: for ORR, it achieves a half-wave potential of 0.86 V and an average electron transfer number of ∼3.90; for the hydrogen peroxide oxidation reaction (HPOR), its onset potential is reduced by over 0.5 V compared to the oxygen evolution reaction (OER). In situ Raman identified *O2- as a central role in bidirectional oxygen electrocatalysis (ORR and HPOR). Utilizing PN-G catalyst, we constructed a rechargeable zinc‑oxygen battery employing an H2O2-mediated electrolyte. This battery delivers a peak power density of 710 mW cm-2 and a round-trip energy efficiency of ∼96% at 5 mA cm-2. This work not only establishes a controllable synthetic route for high-performance metal-free carbon catalysts but also provides a practical approach for designing efficient metal-air batteries.

Polymer-based solid electrolyte (SE) cells promise electrochemical synthesis of pure hydrogen peroxide (H 2 O 2 ), yet the protonation mechanisms governing the two-electron oxygen reduction reaction (2e − -ORR) remain unclear when using pure water as the proton source. Both Langmuir–Hinshelwood (LH, surface *H-mediated) and Eley–Rideal (ER, water-derived proton-coupled) pathways are theoretically plausible, but their practical dominance under SE conditions lacks experimental validation. Herein, we designed a hierarchical Ni─N 2 ─C─O single-atom/NiO nanocluster co-decorated porous carbon nanosheet catalyst (NiSA-NiO/pCNs) that achieved a Faradaic efficiency of 97% and a H 2 O 2 partial current density of 356 mA cm⁻ 2 (equivalent to 6.6 mmol cm −2  h −1 production rate) in a porous SE cell. Analysis of reaction intermediates and the local pH using in situ Raman spectroscopy, kinetic isotope effect, and density functional theory simulations showed the critical role of NiO nanoclusters in tuning the protonation pathway: NiO activates the ER mechanism via fast proton transfer from water dissociation, whereas NiSA/pCNs without NiO preferentially follow the LH mechanism through surface-adsorbed *H intermediates from interfacial transferred proton. These findings establish a catalyst design principle for proton transfer control in solid-state H 2 O 2 electrosynthesis.

The electrochemical oxygen reduction reaction (ORR) offers an alluring and sustainable alternative to the traditional anthraquinone process for hydrogen peroxide (H₂O₂) synthesis. However, challenges remain in developing scalable electrocatalysts and cost-effective reactors for high-purity H₂O₂ production. This study introduces a simple yet effective mechanical mixing method to fabricate a hybrid electrocatalyst from oxidized carbon nanotubes and layered double hydroxides (LDHs). This easily accessible and low-cost catalyst achieves near-perfect Faradaic efficiency (∼100%) with low overpotentials of 73 mV at 10 mA cm⁻2 and 588 mV at 400 mA cm⁻2 in a solid electrolyte cell. Through theoretical calculations and in-situ analyses, we uncover the pivotal role played by the LDH co-catalyst in fine-tuning the local pH at the catalyst/solid-electrolyte interface that drives both the activity and selectivity. We also design a low-cost solid-state reactor using cation-exchange resin (CER) as both a proton conductor and a microchannel for efficient mass transfer, achieving a production rate of 5.29 mmol cm⁻2 h⁻¹ and continuous output concentrations of 11.8 wt.% H₂O₂. Scaled to an industrial area of 2 × 100 cm2, the pilot reactor achieves an impressive H₂O₂ production rate of approximately 127.0 mmol h⁻¹ at 15 A, marking a significant advancement in sustainable H₂O₂ production.

Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) were employed to investigate the presence of hillock-like defects on InAs/GaSb type-II superlattice (T2SL) epitaxial wafers. Through TEM and Inverse Fast Fourier Transformation (IFFT) TEM imaging of the underlying epi-layer substrate, it was discerned that these defects stem from the lower surface layer of the polished InAs substrate. This substrate, characterized by a low dislocation density, is grown using the vertical gradient freeze (VGF) technique. The presence of these defects can be attributed to the sub-surface damage incurred during the substrate polishing process.

As a new type of marine titanium alloy, Ti–6Al–3Nb–2Zr–1Mo (Ti6321) has gained attention for its comprehensive properties such as high toughness, strength, weldability, and corrosion resistance. However, there are only a few reports on fatigue properties of Ti6321. In this study, the dwell fatigue and low cycle fatigue tests were performed under various maximum load stresses with the stress ratio of R = 0. Experimental results revealed that the failure can be classified into brittle and ductile types. Fatigue life decreases with the increase of maximum load stress. The dwell time facilitates the accumulation of plastic strain in each loading-unloading cycle and significantly reduces fatigue life. The stress-strain response in the initial period of loading has a decisive effect on fatigue life for both low-cycle and dwell fatigue. The plastic strain energy density in the first loading cycle and fatigue life satisfies the power law relationship, which can be utilized to predict the load holding and low cycle fatigue life of Ti6321.

The development of high-efficient electrocatalysts with low applied voltage and robust stability is of great importance for electrolysis of water. In this work, a bifunctional electrode has been developed by growing palladium-modified FeCoS2 nanosheet arrays on Ni foam (Pd-FeCoS2 NAs/NF), which can serve as anode and cathode for alkaline water splitting with high activities and ultra-strong durability. The Pd-FeCoS2 NAs/NF shows overpotentials of 130 mV for hydrogen evolution reaction (HER) and 202 mV for alkaline oxygen evolution reaction (OER) at 10 mA cm(-2). The alkaline electrolyzer is built by employing Pd-FeCoS2 NAs/NF as cathode and anode, delivering a current density of 50 mA cm(-2) at 1.59 V. Moreover, the electrolyzer can run stably for 600 h with negligible decline.

Zn ion energy storage devices have received widespread attention because of their high safety, environmental friendliness, low cost, and high energy density. However, Zn metal anodes usually suffer from disadvantages such as dendrite growth, low coulombic efficiency, and volume expansion during plating/stripping, which severely hampers the practical applications. Here, we construct 3D Zn frameworks by exploring different conductive hosts and modify 3D hosts by plating Sn to suppress Zn dendrites and side reactions. The electrode which optimized by electroplating Zn after chemically plating Sn on Cu foam (Sn Cu foam@Zn) exhibits stable polarization voltage distribution and almost 100% coulombic efficiency over 200 cycles of Zn plating/stripping. Furthermore, when pairing with V2O5 cathode, the full cell showed fast reaction kinetics and a capacity of 113 mAhg(-1) after 1000 cycles at a current density of 1 Ag-1, which is 90.4% of the initial capacity. This work provides a new strategy for the development of high-performance Zn anodes.

Developing highly efficient electrocatalysts for selective glycerol oxidation reaction (GOR) is crucial to imple-ment biomass valorization and to advance the energy conversion efficiency of glycerol fuel cells. Herein, a hybrid alkali-acid direct glycerol fuel cell (DGFC) that can not only deliver a high power density but also enable glycerol valorization conversion is demonstrated. Such double-benefits electrochemical device is implemented by in situ growth of FeCoNiCrMnS2 nanoparticles on carbon cloth (FeCoNiCrMnS2/CC) as anode, which exhibits high activity and selectivity for GOR with low overpotential and high Faradaic efficiency toward the formate product. Based on the results of finite element method simulations of element distribution on FeCoNiCrMnS2, the elec-trocatalytic sites was investigate by density functional theory in conjunction with Monte Carlo and machine learning simulations and confirmed that the desired catalytic properties primarily originate from the Ni and Co sites, while Cr and Mn optimized the electronic structure of these sites. The as-developed DGFC can release a maximum peak power density of 50.1 mW cm-2 and stably generate formate with high selectivity. The present work may inspire to contrive the newly advanced energy device and provide fresh impetus for the development of newly high-entropy materials for a variety of application.

A novel filament winding virtual tool is proposed to develop the 3D winding paths on the workpiece contour in real-time. The semi-geodesic and constant-wall-thickness (CWT) trajectories are used to generate the centerline of the 3D path. A tow overlaps processing method and the outer-contour expanding algorithm (OEA) are developed to eliminate the tow interference. The convex helix algorithm (CHA) is proposed to smooth the cliff generated in the interference elimination. The OEA and CHA algorithms are considered due to their high computational efficiency as compared to the traditional algorithms, such as the Backward Search algorithm (BSA) and L-BFGS Algorithm. The prospective virtual tool develops a stable winding path, and experimental results have shown that the 3D path does have advantages over the traditional 2D path in terms of high preservation of the tow path and the prevention of the tow slippage.

Filament winding is a technique that precisely places continuous fibers along a preset path on a rotating mandrel. However, traditional 2D winding paths based on the original mandrel surface ignore the effect of thickness stacking on doffing points. To physically simulate the build-up of tows on the mandrel, a novel numerical method, including the mesh-based directional projection (MDP) and normal adaptive convex helix (NACH) algorithms, is proposed. The MDP algorithm is employed to sort out tow overlaps in the thickness direction, and is 200 times more efficient than the existing algorithms, such as the backward search algorithm. Subsequently, the “cliffs” generated in the overlap removal process are smoothed by the NACH algorithm. Furthermore, the advantages of these two algorithms in terms of efficiency, reliability, and universality are discussed in detail. In summary, a method for developing a physical-based 3D path and ever-updating workpiece contour of pressure vessels is proposed, which serves as an essential reference for high-precision winding and workpiece shape optimization.

A deeper understanding of the uniaxial compression damage behavior and its microscopic mechanisms in closed-cell Polyurethane foam (PUF) at higher strains would be the first step to comprehend its energy absorption behavior in application. A physical-based micro-structure of the PUF model, therefore, is a crucial precondition in the prediction of the material property. A highly efficient physical-based model with adapted periodic boundary conditions (PBCs) is developed to simulate the mechanical behavior of the rigid closed-cell foam using 100 cells, much less than that mentioned in the literature (800 cells). The microstructure characteristics of PUF have been obtained by scanning electron microscopy (SEM), including the cell size distribution, the wall thickness, the cell aspect ratio, etc. Using these parameters, a periodic representative volume elements (RVEs) model based on the Laguerre tessellation with centroidal constraint and capacity constraint (LTCCC) has been proposed. The centroidal constraint and capacity constraint on the LTCCC has a sound physical meaning that the volume distribution of the cells in the RVEs model obtained by the iterations of the weights of the seed points can be precisely matched to that measured using the SEM. Meanwhile, the features of the RVEs model, including the number of the faces per cell and the number of the edges per face, also match those of the real foam. The anisotropic compressive behavior of the PUF is predicted and well validated using the experimental results. The quasi-static crushing progress of the cells as well as the struts is detailed discussed using the proposed model to reproduce the layer-wise collapse phenomena and reveal the reasons that cause the different crushing behavior in axial direction and perpendicular to the axis direction.

Non-swelling super-tough polymer hydrogels have great potentials for stable applications in wet conditions. It has been challenging since most polymer hydrogels uptake water from the environment and swell, which de-teriorates the mechanical strength and toughness. Here, we present multi-responsive non-swelling polymer hydrogels (PHFGs) by using amphiphilic triblock copolymer micelles as non-covalent crosslinkers. Pluronic F127 (or polyethylene oxide -block-polypropylene oxide -block-polyethylene oxide, PEO-PPO-PEO) (F-127) micelles are used as a prototype for the synthesis of micelle-crosslinked poly-(2-hydroxyethylene methacrylate) (PHEMA) hydrogels, without using any modification of F-127 or other crosslinkers. FT-IR and 1H NMR studies provide first evidence that F-127 micelles form extensive hydrogen bonding and hydrophobic association with PHEMA chains. The non-covalent crosslinked hydrogels show a high fracture elongation about 460 %, a fracture strength about 240 kPa, and a fracture toughness about 660 kJ/m3. Negligible swelling is observed for the polymer hydrogels in aqueous solutions. The hydrogels are self-healable, and responsive to variations in pH or water content to change volume, shape, and transparency. Such multiple-responsive polymer hydrogels are utilized as smart switches and shape memory materials that are actuated by environmental stimuli in a controllable manner.

Total reflection X-ray fluorescence spectroscopy(TXRF)and X-ray photo-electron spectroscopy (XPS)have been used to investigate residual impurities and oxides on polished InAs substrate surface wet cleaned by different solution combination. Metal impurities Si,K and Ca are routinely detected on the cleaned InAs sur?face and their concentration change with the variation of solution combination. A large quantity of particles(80 nm size)is measured on the InAs substrate surface with higher residual impurity concentration. An effective wet chemical cleaning procedure is presented to prepare InAs substrate surface with less residual impurity,small parti?cle quantity and thin oxide layer,which are beneficial to high quality epitaxial growth.

Undoped InAs (100) substrate wafers prepared by liquid encapsulated Czochralski (LEC) and vertical temperature gradient freezing (VGF) methods have been studied and compared in their epi-ready state. The substrate surface defects have been analyzed by surface scanner KLA candela, Energy Dispersive X-Ray Spectroscopy (EDAX), Total-reflection X-ray fluorescence spectroscopy (TXRF), with an aim to find the contrast between LEC-InAs and VGF-InAs substrates. It is found that the VGF wafers have lower surface point defects and good stoichiometry compared with the LEC-wafer. VGF-InAs is more favorable to LEC-InAs for oxide thermal desorption and midwavelength infrared（MWIR）epitaxial layer growth with low defect density.

The filament winding process is a competitive performing technology for nuclear fuel cladding tubes due to its high automation. The study of the yarn path on the mandrel surface is vital to design and produce the cladding tube with the desired mechanical properties, reducing manufacturing time and costs. The geodesic and semi-geodesic trajectories are used to create a 3D yarn path in this paper. A 3D yarn path optimization method based on the principle of minimum potential energy is proposed to simulate the overlap effect in accord with the real winding process. The finite element (FE) mesh based on the 3D yarn path has been used for the mechanical analysis of the cladding tube. The embedded region constraint is applied to define the interaction between the matrix mesh and the yarn mesh to model the meso-structure of the cladding tube. Based on the meso-scale FE model, the mechanical behavior of the wound SiC f /SiC nuclear fuel cladding tube is studied in detail. The results show that due to the neglect of the overlap effect, the conventional laminate model overestimates the cladding tube strength. The proposed meso-scale FE model can accurately predict the failure of the cladding tube. The results also confirm that the creation of a 3D yarn path and the derived meso-scale FE model, representing an accurate wound structure, are of importance to the prediction of the performance of the cladding tube.

A generalized multiscale (micro-macro) finite element (FE) model for SiC-fiber reinforced SiC-matrix ceramic (SiCf/SiC) nuclear fuel claddings is established. In the macro level, the solid mesh of braided preform, which can be tailored by machine settings (braid angle, yarn width, and so on), is generated based on the braiding process simulation using the dynamic FE-solver, hiring the contact constraints. The matrix mesh and the yarn mesh are integrated by the embedded region constraint, with which the meshing difficulties can be avoided. In the micro-UD model, the progressive damage of the ceramic matrix is modeled using the phase field method (PFM) and the fracture is captured by Mohr–Coulombs criterion, which are stable and efficient in the description of the brittle crack initiation, coalition, and branching. Based on this multiscale model, the mechanical behavior of the braided SiCf/SiC nuclear fuel cladding tube is studied in detail. The superiorities over the homogenized tube model are demonstrated, too.

An advanced modeling strategy for notched ceramic matrix composite coupons with patch reinforcement was proposed to investigate the failure mechanisms. This model considered the tailored fiber–placed (TFP) yarn details obtained from the design phase and the embedded element concept which was used to successfully overcome the meshing difficulties. Inter-ply “glue” layers were simulated using the surface-based contact cohesive element method, so the delamination due to interfacial material discontinuity and damage can be well reproduced and analyzed. For composite ply, the energy-based composite progressive damage model that is independent of the mesh size was applied. Virtual test campaign was performed with a variety of geometrical and material parameters, and the damage and failure mechanisms based on the stress analysis can be revealed to support the design optimization of patch reinforcement.

The effect of porosity on the effective thermal conductivities calculation for continuous SiC fiber reinforced SiC matrix composites (SiCf/SiC) was studied in this work by finite element modeling. A three-dimensional representative volume element (RVE) containing detailed geometric features (fibers, matrix, fiber coatings and pores) was generated to rebuild the microstructure of SiCf/SiC and used to numerically calculate the effective transversal and longitudinal thermal conductivities of SiCf/SiC. Markworth model and parallel model were chosen as theoretical models to calculate the transversal and longitudinal thermal conductivities respectively. The numerical results obtained by RVE models were validated by comparison with the theoretical and experimental results. The results highlight the existing theoretical models cannot well predict the transversal thermal conductivity of SiCf/SiC with the existence of pores. In the analysis of the effect of porosity, real pore structure in SiCf/SiC was investigated to revel the relationship between porosity and the effective thermal conductivities. In the case of longitudinal thermal conductivity, the parallel model plus the linear term of porosity can still be used to predict the longitudinal thermal conductivity. As for the transversal thermal conductivity, a more proper Markworth model for SiCf/SiC transversal thermal conductivity calculation calibrated by incorporating porosity is proposed to efficiently calculate the transversal thermal conductivity at the end of this paper.

Creep, as one of the mechanical properties for evaluating the resistance of deformation under a persistent stress, is extremely important in the application of metal/ceramic nanolaminates. In this work, the creep behaviors of Al/SiC nanolaminates with layer thickness of 10 nm and 100 nm were studied by means of nanoindentation in the temperature range from 25 degrees C to 150 degrees C. It was found that the stress exponent of nanolaminates for layer thickness of 100 nm increased with an increase in temperature. The stress exponent of Al was obtained by inverse methodology based on the finite element simulations, indicating that the creep mechanism changed from dislocation-grain boundary interaction to Coble creep. In the contrary, nanolaminates with layer thickness of 10 nm exhibited temperature-independent creep behaviors. This was rationalized by the co-deformation of Al and SiC layers beneath the indenter, which was dominated in the whole temperature range. In addition, all of these conclusions were further confirmed by the detailed transmission electron microscopic observation, the activation energy and the activation volume analysis.

The effect of elastic and thermal mismatches between fiber and matrix on the push-in mechanism and interfacial shear strength () measurement of typical polymer and ceramic matrix composites was studied in this work by comprehensive finite element modeling of push-in response, using carbon fiber-reinforced epoxy and SiC matrix (C-f/epoxy and C-f/SiC) as model materials. The results highlight a strong effect of fiber-localized environment on the push-in response, especially for the C-f/epoxy with large elastic mismatch. This led to errors to estimate if applying directly the standard shear-lag model to calculate tau(0) according to the push-in response. Calibrations of the shear-lag model were thus performed in both C-f/epoxy and C-f/SiC, and the results suggest a negligible effect of the elastic mismatch in the C-f/SiC due to the comparable elastic properties between fiber and matrix. The shear-lag model can thus well estimate based on the push-in force-displacement curves. If the residual thermal stress was considered, the push-in deformation was altered by increasing evidently the critical load leading to interfacial fracture, which led to overestimation of . This is a consequence of the large shear stress level concentrated mainly at the fiber/matrix interface. Detailed parametric push-in simulations were afterwards performed to incorporate the effect of interfacial shear stress in the standard shear-lag model, and a more proper shear-lag model calibrated by incorporating both elastic and thermal mismatches was finally proposed.