This paper presents the development of a compact, three-electrode electrochemical device functionalized by a biocompatible layer of hyaluronic acid methacrylate (HAMA) hydrogel for the adsorptive removal of detrimental lead (Pb(II)) ions in aqueous solutions. An adsorption mechanism pertaining to the observed analytical performance of the device is proposed and further experimentally corroborated. It is demonstrated that both the molecular interactions originating from the HAMA hydrogel and electrochemical accumulation originating from the electrode beneath contribute to the adsorption capability of the device. Infrared spectral analysis reveals that the molecular interaction is mainly induced by the amide functional group of the HAMA hydrogel, which is capable of forming the Pb(II)–amide complex. In addition, inductively coupled plasma mass spectrometric (ICP-MS) analysis indicates that the electrochemical accumulation is particularly valuable in facilitating the adsorption rate of the device by maintaining a high ion-concentration gradient between the solution and the hydrogel layer. ICP-MS measurements show that 94.08% of Pb(II) ions present in the test solution can be adsorbed by the device within 30 min. The HAMA hydrogel-modified electrochemical devices exhibit reproducible performance in the aspect of Pb(II) removal from tap water, with a relative standard deviation (RSD) of 1.28% (for n = 8). The experimental results suggest that the HAMA hydrogel-modified electrochemical device can potentially be used for the rapid, on-field remediation of Pb(II) contamination.

As an inorganic–organic composite material, cement and emulsified asphalt (CA) mortar has been used widely in ballastless slab track structures, and its performance is influenced significantly by environmental conditions. In this study, we tested the long-term creep of CA mortar at different temperatures using a self-designed loading device, and explored the mechanisms by which high temperatures influence CA mortar creep based on several microscopic testing methods. The results indicated that high temperatures cause the creep degree and rate of CA mortar to increase significantly. Subsequent to creep at high temperatures, the mechanical properties and microstructure of CA mortar changed remarkably, and asphalt migration may be an important cause of changes in CA mortar at high temperatures. This will be useful for future studies of the evolution of CA mortar performance under long-term service conditions.

Two-dimensional (2D) GaSe is a promising candidate for nonlinear photonic applications due to its strong second-order optical response. However, precise control over its morphology and stacking order during synthesis remains a significant challenge. Herein, we report a vapor-phase growth strategy that enables the controlled synthesis of 2D GaSe with tunable crystal shapes and stacking configurations by adjusting precursor flux and temperature gradients. The growth mechanism is elucidated through a combined experimental and theoretical approach, involving density functional theory and kinetic Wulff construction analysis. We demonstrate that the competition between diffusion-limited and attachment-limited growth regimes governs the edge propagation rates, leading to the formation of triangular and nonconventional morphologies. Furthermore, we reveal that distinct stacking orders result in pronounced variations in SHG intensity and polarization dependence. These findings highlight the crucial role of stacking order in modulating the nonlinear optical properties of 2D GaSe and offer a rational pathway toward the design of layered semiconductors with tailored optical functionalities.

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) have emerged as promising semiconductors beyond the limits of conventional scaling. Yet, wafer-scale synthesis remains hindered by the pervasive generation of atomic defects that degrade electronic applications. Here, we develop a eutectic-vapor growth strategy that enables direct synthesis of highly crystalline 2D MoS2 at unexpectedly low temperatures. This method simultaneously avoids incomplete precursor reaction and the defect-promoting conditions inherent to high-temperature growth. First-principles calculations combined with ab initio molecular dynamics reveal that Mo–S precursors undergo a eutectic interaction with halide salts, producing volatile molecular growth species at reduced temperatures. Potassium ions adsorbed at the MoS2 edge substantially lower the incorporation barrier of reactive growth units, which is expected to reduce the propensity for defect formation during crystal growth. This eutectic-mediated growth mechanism provides a chemically grounded and broadly applicable route for low-temperature synthesis of 2D TMDCs with substantially reduced defect densities.