There's something in the air … A nanocomposite consisting of well-dispersed SnO(2) and Pt nanoparticles on reduced graphene oxide (see the high-resolution TEM image) exhibited very high responses to hydrogen at concentrations between 0.5 and 3% in air, with response times of 3-7 s and recovery times of 2-6 s. The sensor was prepared by a straightforward microwave-assisted non-aqueous sol-gel approach.

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Scheme 1 . Procedure of iron oxide/reduced graphene oxide composites fabrication.

A reaction-diffusion model is investigated to understand infective environments in a man-environment-man epidemic model. The free boundary is introduced to describe the expanding front of an infective environment induced by fecally-orally transmitted disease. The basic reproduction number R F 0 (t) for the free boundary problem is introduced, and the behavior of positive solutions to the reaction-diffusion system is discussed. Sufficient conditions for the bacteria to vanish or spread are given. We show that, if R 0 ≤ 1, the bacteria always vanish, and if R F 0 (t 0 ) ≥ 1 for some t 0 ≥ 0, the bacteria must spread, while if R F 0 (0) < 1 < R 0 , the spreading or vanishing of the bacteria depends on the initial number of bacteria, the length of the initial habitat, the diffusion rate, and other factors. Moreover, some sharp criteria are given. MSC: primary: 35R35; secondary: 35K60

Es liegt was in der Luft …︁ Ein Nanokomposit aus dispergierten SnO2‐ und Pt‐Nanopartikeln auf reduziertem Graphenoxid (siehe TEM‐Bild) zeigt ein sehr starkes Ansprechverhalten auf Wasserstoff in Konzentrationen zwischen 0.5 und 3 % in der Luft, bei Ansprechzeiten von 3–7 s und Erholungszeiten von 2–6 s. Der Sensor wurde über einen einfachen mikrowellenunterstützten nichtwässrigen Sol‐Gel‐Prozess hergestellt.

The benzyl alcohol route is used to decorate reduced graphene oxide (RGO) nanosheets with iron oxide (FeOx) nanoparticles. The resulting FeOx/RGO composites combine both electrical double‐layer capacitive and pseudocapacitive behaviors of RGO and FeOx, respectively, owing to the hybrid nanostructure. In 1 M Na2SO4 aqueous electrolyte, the capacitance of the FeOx/RGO electrode reaches 126 F g−1 in a negative potential range from −0.8 to 0.0 V (vs. Ag/AgCl) and 97 F g−1 in the extended potential window from −0.8 to +0.7 V (vs. Ag/AgCl). By using the benzyl alcohol route, a higher concentration of iron precursor leads to full surface coverage of the RGO nanosheets by smaller FeOx nanoparticles, forming a close‐packed layer that limits the restacking of RGO nonosheets in the dry state. The resulting FeOx/RGO composite gains the same power capability as RGO and a higher energy density than raw FeOx, owing to this well‐designed morphology,.

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