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The image graininess of displays is a subjective indicator and is very difficult to be evaluated quantitatively. In this paper, we will introduce a visual optical simulation system and the quantitative evaluation criteria for graininess. [ABSTRACT FROM AUTHOR]

Mucosal antibodies in the upper respiratory tract are the earliest and most critical responders to prevent respiratory infections, providing an indication for the rapid evaluation of immune protection. Here, we report a microfluidic particle counter that directly visualizes mucosal antibody levels in nasal mucus. The mucosal anti-SARS-CoV-2 spike receptor binding domain (RBD) antibodies in nasal secretions first react with magnetic microparticles (MMPs) and polystyrene microparticles (PMPs) that are surface-modified to form a "MMPs-anti-spike RBD IgG-PMPs" complex when RBD is present. After magnetic separation and loading into the microfluidic particle counter, the free PMPs, which are reduced with increasing anti-spike RBD IgG antibody levels, are trapped by a microfluidic particle dam and accumulate in the trapping channel. A sensitive mode [limit of detection (LOD): 14.0 ng mL−1; sample-to-answer time: 70 min] and an equipment-free rapid mode (LOD: 37.4 ng mL−1; sample-to-answer time: 20 min) were achieved. Eighty-seven nasal secretion (NS) samples from vaccinees were analyzed using our microfluidic particle counter, and the results closely resemble those of the gold-standard enzyme-linked immunosorbent assay (ELISA). The analysis shows that higher antibody levels were found in convalescent volunteers compared to noninfected volunteers. Together, we demonstrate a rapid kit that directly indicates immune status, which can guide vaccine strategy for individuals and the government. [ABSTRACT FROM AUTHOR]

The contact heat conduction problem between the rough sliding surfaces was studied through secondary development of finite element software ABAQUS.The thermal contact conductance was defined as a function of the sliding speed,the local contact pressure,material properties and the surface roughness, and the effeecs of three dimensionless parameters were also analyzed.The results reveal that reciprocating motion has a significant influence on contact heat conduction.When heat conduction between sliding surfaces reach a stable stape,the dimensionless mean heat flux per unit time increases with the rising dimensionless parameters η and ω the heat conduction decreases with the reduction of the contact pressure and the growth of the surface roughness.Besides,the variations of the dimensionless average temperature are consistent with those of the dimensionless average heat flux.

Resisting extreme loading and thermal ablation encountered by aerospace devices demands for high performance engineering materials. Aerogels have achieved satisfactory thermal insulation but the intrinsic brittleness of porous skeletons fail to ensure their normal operation under severe stress fields. Herein, aramid nanofibers (ANFs) are processed into tough 3D aerogel monoliths via a multi‐scale toughening strategy, involving unidirectional freeze‐casting‐enabled microstructure orientation and acid‐assisted nanofiber cross‐linking. Scalable production of ANFs aerogels is realized through fast air‐drying without excessive energy consumption. The aligned sheets in ANFs aerogels enable extreme thermal conductivity of 15.8 mW m−1 K−1, superinsulation from −130 to 300 °C, and durable combustion protection for 20 min. Particularly, highly aggregated nanofibers assemble into dense ANFs skeletons, endowing the tough aerogels with superior specific tensile strength (89 MPa cm3 g−1), ultra‐high toughness (1.3 MJ m−3), and impressive fracture energy (7.36 kJ m−2). Such mechanical properties are highly resistant to harsh environments, including water erosion (7 days) and high temperature baking (30 days). Moreover, ANFs aerogels exhibit two to three times more energy dissipation than commercial foams against ballistic impact at 140 m s−1. This integrated mechanical and thermal robustness may pioneer the potential application in impact‐thermal coupled safeguard for aerogel materials. [ABSTRACT FROM AUTHOR]