Photocatalysts with oxygen vacancies (OVs) have exhibited exciting activity in N2 photofixation due to their superiority in capture and activation of N2. However, the surface OVs are easily oxidized by seizing the oxygen atoms from water or oxygen during the catalytic reaction. Here, it is reported that the grain boundaries (GBs) in nanoporous WO3 induce plenty of operando OVs under light irradiation to significantly boost catalytic activity toward N2 photofixation. Impressively, nanoporous WO3 with abundant GBs (WO3‐600) exhibit an ammonia production rate of 230 µmol gcat.−1 h−1 without any sacrificial agents at room temperature, 17 times higher than that for WO3 nanoparticles without GBs. Moreover, WO3‐600 also manifests remarkable stability by maintaining nearly ≈100% catalytic activity after ten successive reaction rounds. Further mechanistic studies reveal that both OVs and GBs regulate the band structures of WO3 nanocrystals, as well as favor the delivery of photogenerated electrons to adsorbed N2 by enhancing W–O covalency. More importantly, plenty of operando OVs induced by GBs generate during catalytic reaction, directly contributing to the excellent catalytic performance for WO3‐600. This work opens a novel avenue to developing efficient photocatalysts by construction of operando OVs.

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Objectives. To examine the trends of leisure activity engagement among the oldest old in China for the past 2 decades. Methods. Our panel data came from the Chinese Longitudinal Healthy Longevity Survey, which systematically asked respondents about their current participation in leisure activities over a 20-year period. The final sample contained 66 789 interviews from 1998 to 2018. We applied generalized estimating equations regression models in our analysis. Results. Compared with 1998, odds ratios of television watching among Chinese oldest old individuals increased by about 2 to 3 times in 2018. Meanwhile, the odds ratio of exercise declined by 24%, mostly in men; playing cards and mah-jongg declined by about 30% for men. Results also showed that reading became less popular in the oldest old, and Chinese women tended to do more housework than before. Conclusions. Our findings indicated that Chinese oldest old persons have become more sedentary and solitary in the past 2 decades. The negative trend in leisure activity engagement among the elderly Chinese population warrants policy attention, and the urgent development of public health interventions is required to reverse such trends. (Am J Public Health. Published online ahead of print August 20, 2020: e1–e3. doi:10.2105/AJPH.2020.305798)

In the fiber-reinforced resin matrix composites, the “interphase” is an important component. And the “cohesive element” is usually used to characterize the mechanical properties of “interphase” in numerical models based on the general finite element software ABAQUS. But the corresponding parameters of it are difficult to be determined. So the single-carbon fiber-reinforced resin matrix composites are used as the main research object and the method combining resistance experiment and numerical analysis is adopted. Then in the numerical models of three different single-carbon fiber composites (CCF/epoxy128, CCF/epoxy5228, CCF/Bismaleimide5428), the parameters of the “cohesive element” are analyzed and determined. It turned out that in CCF/Bismaleimide5428, the parameters are much higher (they are 10–12 GPa). It is also demonstrated that the ability of transferring load of “interphase” is much stronger in it than the other single fiber composites. What’s more, these parameters will be used for the numerical analysis of macroscopic mechanical properties of composites in future.