Smartphones offer multimedia convergence in a single device, ubiquitous access to media, and constant connections with others. The rapid rise of smartphone use calls for more scholarly attention paid to users’ media usage and time expenditure. This study aims to (a) understand smartphone usage patterns by examining time spent using smartphones and task switching between mobile applications (apps), and (b) test the validity of self-reported measures of these behaviors by comparing self-reports with log data from the smartphone. Data were collected from 50 participants over 1 week. Results show that on average participants spent 2 hours 39 minutes on their smartphone and made 101 app switches per day. Among other findings, social networking was the most used app category, age was a significant demographic factor, and participants, especially heavy smartphone users, overestimated their mobile app usage. Theoretical and practical implications of these findings are discussed.

The hydrogen bond network reconstruction at the titanium/water interface was monitored by Raman spectroscopy. In addition, the adsorption properties and the surface electron properties of hydrogen bond cluster (HBC) configurations were analyzed using adsorption energy, work function, Mulliken charge population, and density of states (DOS) by the first-principles method based on density functional theory (DFT). Our results show that the hydrogen bond network of the aqueous solution is reconstructed under the interaction with the anatase TiO2(101) surface with the transformation of the chain and free hydrogen bonds to complex hydrogen bonds. The adsorption energy of a single water molecule and HBC on the anatase TiO2(101) surface are the lowest with the 1-DD-h (−0.851 eV) and 3-D-h-DDA (−1.048 eV) configurations, respectively. Over the long term, artificially regulating the structure of the HBC might be an effective and general way to slow down the metal anodic reaction without surface modification. Furthermore, the surface charge concentrates on the bridging oxygen atom, which will be the active site of the interface reaction. It is helpful to clarify the anodic corrosion reaction mechanism of the titanium spontaneous oxide film/water interface.

The development of the efficient and economical catalysts for the oxygen reduction reaction (ORR) is an important issue for the commercialization of metal-air batteries. Herein, a silver-doped δ-MnO2 dispersed on carbon powder (Ag-MnO2/C) was synthesized by a facile route. The specific surface area of Ag-MnO2/C is more than three times higher than that of MnO2/C. Moreover, Ag-MnO2/C shows much higher catalytic activity toward ORR than MnO2/C or Ag/C. The half-wave potential of Ag-MnO2/C is much more positive compared with that of 20% Pt/C. Ag-MnO2/C also exhibits an excellent long-term stability and the ORR current retention keeps 97.1% after aging for 45000 s. Using Ag-MnO2/C as the ORR catalyst, the peak power density of Al-air battery reaches 315 mW cm−2 which is almost the highest record.

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