南京工程学院

The development of efficient hydrogen storage technologies remains a critical challenge for large-scale hydrogen energy applications. Herein, a NiCo solid-solution (NiCo) supported on dual-phase TiO2 was incorporated into an Mg-Al-based hydrogen storage alloy to enhance the hydrogen storage performance of MgH2. The Mg90Al10-10 wt.% NiCo-TiO2 exhibits a low onset dehydrogenation temperature of similar to 178 degrees C. At 175 degrees C, similar to 5.0 wt.% H2 is absorbed within 1200 s under 3 MPa hydrogen pressure, while similar to 4.0 wt.% H2 is released within 1500 s at 250 degrees C under 0.005 MPa hydrogen pressure. Remarkably, the composite retains 99.81 % of its hydrogen storage capacity over 20 cycles with negligible kinetic degradation, accompanied by a reduced dehydrogenation activation energy ( Ea ) of 63.35 kJ mol-1 and dehydrogenation enthalpy ( OH ) of 69.04 kJ mol-1. Density functional theory calculations (DFT) and molecular dynamics simulations (MD) reveal that the NiCo on dual-phase TiO2 remains highly dispersed and structurally stable during re-/dehydrogenation. The incorporation of Co effectively suppresses Ni migration and the formation of intermetallic compounds, leading to enhanced structural robustness. Meanwhile, NiCo d-orbital coupling creates a hybrid d-band center that strengthens metal-hydrogen interactions and facilitates hydrogen adsorption. The synergistic interplay between electronic modulation and structural stability ensures the superior hydrogen storage kinetics and cycling durability of Mg90Al10-10 wt.% NiCo-TiO2. (c) 2026 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Abstract In saline-alkali or coastal regions, sulfate attack is a primary factor causing performance deterioration of concrete structures. Hence, concrete cold joints, being weak interfaces of structures, warrant attention regarding their shear deterioration performance in sulfate attack environments. This study employed molecular dynamics simulations to establish models characterizing concrete cold joints, specifically a CSH-a-to-CSH-b (CC) interface and a CSH - a - to - SiO 2 (CS) interface. The influence of different Na 2 SO 4 solution concentrations (0%, 5%, and 10%) on the shear deterioration behavior of these interfaces was investigated. The results indicated that as the Na 2 SO 4 concentration increased, the degree of interfacial erosion damage became more pronounced. The penetration of Na 2 SO 4 solution altered the interfacial ionic interactions, making the substrate ions more likely to bond with the solution ions, thereby further deteriorating the shear performance of the interface. When the Na 2 SO 4 concentration increased from 0% to 5% and then from 5% to 10%, the maximum shear stress of the CC interface decreased by 68.8% and 31.0%, respectively, whereas that of the CS interface decreased by 62.5% and 39.4%, respectively. Additionally, Na 2 SO 4 solution significantly influenced the shear failure mode of the model. In the absence of Na 2 SO 4 erosion, shear failure occurred within the CSH-a substrate with lower strength and unstable bond energy. However, as the Na 2 SO 4 concentration increased, the failure mode shifted to distinct interfacial shear failure. This study reveals the influence of sulfate concentration at the nanoscale on the shear behavior of concrete cold joints, providing a new perspective for understanding their deterioration mechanisms in sulfate attack environments.

Motivated by the fact thatpower generation firms are confused about how to trade off low-carbon technologies and renewable energy investment, this paper develops three models to investigate power generation strategies on carbon reduction. First, by the methods of mathematical optimization and game theory, we compare electricity market participants’ two strategies under centralized and decentralized channel structures. We then discuss how production intermittencyaffects the strategies of both the generation firm and the retailer. Finally, we concentrate on the effects of heterogeneous consumer low-carbon behaviors on consumer surplus and carbon reduction strategies. The key findings are as follows. (1) Decentralizing the electricity channel may, counterintuitively, lower the electricity price. (2) If the unit carbon emission is small and the carbon price is sufficiently high, low-carbon technologies not only reduce emissions but also yield higher profits for the generation firm; however, if the unit carbon emission is high, renewable energy investment should be regarded as the preferred alternative. (3) The power generation firm is motivated to adopt the renewable energy strategy only when both the proportion of low-valuation consumers and their valuations are sufficiently large. (4) Several “win–win” conditions exist, balancing short-term profitability and long-term sustainability.

This paper presents a thermo-mechanical-electro coupling dynamic model for the free and forced vibration analysis of rotating graphene nanoplatelets (GNPs)-reinforced piezoelectric composite microplates subjected to external mechanical and electric loads in thermal environment. Three different GNPs dispersion patterns describe the thickness-wise variations of material properties, which are then evaluated by the extended rule of mixture and Halpin–Tsai micromechanics model. Based on the first-order shear deformation theory (FSDT) and modified couple stress theory (MCST), the governing equations for the rotating piezoelectric composite microplate are established by the Hamilton’s principle, and are subsequently discretized by the Chebyshev-based Galerkin method. The complex mode analysis method is adopted to deal with the free vibration and the four-order Runge–Kutta-Merson’s algorithm is utilized to solve the dynamic responses. The convergence and comparative studies are first carried out to validate the effectiveness of the present method. The effects of load type, damping coefficient, angular velocity, hub radius ratio, small-scale parameter, external voltage, temperature rise as well as the dispersion pattern, weight fraction and piezoelectricity of GNPs on the modal characteristics and dynamic responses of the rotating piezoelectric composite microplates are discussed in detail. The coupling of rotational and deformation motions in the present model demonstrates comprehensive and complicated modal characteristics. The numerical results show that GNPs are the great potential reinforcements for improving the structural stiffness and piezoelectric performance in design of smart piezoelectric composite structures.

CONTEXT:Energetic materials based on bis(4-nitropyrazole)-bridged nitrogen-rich heterocycles are designed, and their physical and chemical properties are fully investigated. Their heats of formation, detonation performance, and impact sensitivities are fully investigated. The results indicate that the addition of a tetrazole/-N3 functional group contributes to an increase in the heats of formation of the designed compounds, while the incorporation of a tetrazole/-C(NO2)3 functional group is beneficial for enhancing their detonation performance. By comprehensively balancing energy performance and stability, candidate compounds A2 and E2 are screened out since these compounds possess better detonation performance and lower impact sensitivities than those of RDX. To further understand the physicochemical properties of the selected compounds, electronic structures such as frontier molecular orbitals and molecular electrostatic potential are simulated and analyzed. METHOD:The optimization of the designed compounds is performed with the Gaussian 16 program suite using the DFT-B3LYP method at the 6-311G(d,p) level. Multiwfn_3.8_dev is used to compute molecular surface properties. Employing the VMD program, the molecular electrostatic potential (ESP) distributions for compounds A2 and E2 are plotted. The initial decomposition mechanism and total decomposition process of A2 are investigated using the CASTEP code.