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Perovskite degradation induced by surface defects and imperfect grain boundaries of films seriously damages the performance of perovskite solar cells (PSCs). Meanwhile, conventional organic molecules cannot maintain the long‐time passivation effects under the stimulation of external environmental factors. Here, efficient and stable grain passivation in perovskite films is realized by preparing formic acid‐functionalized 2D metal–organic frameworks (MOFs) as the terminated agent. Through robust interactions between exposed active sites and PbI2, the 2D MOFs tightly caps the surface of PbI2‐terminated perovskite grains to stabilize the perovskite phases and aids the adhesion of adjacent grains. The MOFs mainly distributed at the grain boundaries of the perovskite film is directly observed at the microscopic scale. The modified perovskite films have regular morphology, lower defect density, and superior optoelectronic properties. Benefiting from the suppressed charge recombination and faster charge extraction, a power conversion efficiency of 21.28% is achieved for the best‐performing PSC device. The unencapsulated PSCs with the MOFs modification maintain 88% and 81% of their initial efficiency after 750 h heating at 85 °C under N2 atmosphere and more than 1000 h storage in ambient environment (25 °C, RH ≈ 40%), respectively.

Antibiotic contamination of water bodies is a major environmental concern. Exposure to superfluous antibiotics is an ecological stressor correlated to the development of antibiotic resistance. Thus, it is imperative that effective methods are developed to simultaneously detect and remove such antibiotics so as to avoid inadvertent release. Herein, two flexible three-dimensional (3D) zinc-based metal–organic frameworks (MOFs) {[Zn2(bcob)­(OH)­(H2O)]·DMA} n (ROD-Zn1) and {[Zn­(Hbcob)]·(solvent)} n (ROD-Zn2) (H3bcob = 1,3-bis­((4′-carboxylbenzyl)­oxy)­benzoic acid) with rod second building units (SBUs) are successfully prepared. Their exceptional water and chemical stabilities (toward both acid and base), fast sorption kinetics, and unique framework endow the MOFs with excellent uptake capacity toward various antibiotics in the aqueous environment. The adsorption performance was further optimized by one-pot preparation of MOF-melamine foam (MF) hybrid composites, resulting in a hierarchical microporous–macroporous MOF@MF system (ROD-Zn1@MF and ROD-Zn2@MF), which are readily recyclable after adsorptive capture. The mechanisms of adsorption have been deeply investigated by static and competitive adsorption experiments. In addition, the MOFs exhibit excellent fluorescent properties and quenched by trace amounts of antibiotics in water solution. Therefore, ROD-Zn1 and ROD-Zn2 present a dual-functional performance, being promising candidates for detection and removal of antibiotics.

The linear stability of Bingham-plastic fluid flow between two concentric cylinders rotating independently and with axial sliding of the inner cylinder (spiral Couette flow) is studied. Bingham fluid exhibits a yield stress in addition to the plastic viscosity, which has some inhibiting effects on the competition between the centrifugal and shear instability mechanisms owing to the inter-relationship of the azimuthal and axial velocities. Islands of instability, which are found in the spiral Couette flow of Newtonian fluids, may not exist owing to the effect of yield stress. The possibility of the yield surface falling between the cylinders is analysed. Although small perturbation waves appearing on the yield surface are considered, the yield surface, which has been treated as a free surface, has little effect on the flow stability. The effects of the axisymmetric and non-axisymmetric perturbation on flow stability are both presented. Both the rotation of the outer cylinder and a decrease of the gap between the cylinders have stabilizing effects.

The “smart” fluorescent material RhB-CDs@1 contains functions of multicomponent recognition, including the detection of quinolones, tetracyclines, nitrofurans and MnO4− in aqueous solution.

The performance of a micro propulsion system is determined primarily by the performance of the micro nozzles. A rectangular cross-section convergent–divergent micro nozzle, with a throat width of 20 µm and an expansion area ratio of 1.7, is fabricated and studied using experiment and numerical simulation. Experiments are conducted to measure the mass flow rates and pressure distributions near the nozzle's throat under various outlet pressures. The results of the numerical simulations accord with the experimental data. Moreover, differences between the micro scale flow and the conventional scale flow are discovered from the simulation results. The Mach number near the downstream position of the micro nozzle's throat is lower than that in the conventional nozzle. In the divergent region of the micro nozzle, there is a supersonic area instead of the shock wave that usually occurs in the conventional scale nozzles. The results of the numerical simulation also show that the position of the sonic point moves away from the throat towards the outlet with the decrease in the size of the nozzle. This particular behavior is attributed to the higher viscous dissipation in micro nozzles as compared to that in the conventional scale nozzles.

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