Lin Shi

Changing the wettability and surface texturing have a significant impact on lubrication. In this study, the researchers used the molecular dynamics method to investigate how adjusting the interaction between alkanes and the wall affects oil film morphology and frictional properties under boundary lubrication. The findings revealed that the bearing capacity was influenced by both the morphology of the oil film and the strength of solid–liquid adsorption. In cases where the walls had weak wettability, the alkanes formed clusters to effectively separate the walls, while in cases where the walls had strong wettability, the oil film spread and formed a strong adsorption film. The super oleophilic textured surface could enhance the oil film adsorption capacity and replenish the oil film to the friction area in time, and the super oleophobic smooth surface could further reduce the friction coefficient. Therefore, a composite surface consisting of a super oleophilic textured surface and a super oleophobic smooth surface can be designed to enhance the bearing capacity of the oil film and reduce friction.

MoS₂ exhibited excellent bearing capacity, and a large-area of MoS₂ coated on the asperity surface could effectively prevent asperity contact, reduce friction coefficient and wear.

The heat transfer performance is improved as surface temperature increases, but the rise of surface temperature increases the flow resistance when solid–liquid interaction is weak but decreases the flow resistance when solid–liquid interaction is strong.

In this paper, a 2D periodic structure made of tungsten (W) grating patch on a thin Al ₂ O ₃ spacer and an opaque W film is proposed, as a broadband selective thermal emitter. We numerically investigated the spectral emissivity of the structure from the deep by finite-difference time-domain method. Geometric parameters effects on the emissivity are discussed and the mechanisms of magnetic polaritons in the structure are further analyzed in detail. In addition, by adding another metal-dielectric stack upon the pre-existing grating structure, the emissivity of the composite structure can be further enhanced, and the normal emissivity exceeds 0.95 in the wavelength range of 0.65–1.95 μ m, some even close to unity. Furthermore, the composite structures are found to exhibit insensitivity to polar angle and polarization.