SnO2 nanowire gas sensors have been fabricated on Cd−Au comb-shaped interdigitating electrodes using thermal evaporation of the mixed powders of SnO2 and active carbon. The self-assembly grown sensors have excellent performance in sensor response to hydrogen concentration in the range of 10 to 1000 ppm. This high response is attributed to the large portion of undercoordinated atoms on the surface of the SnO2 nanowires. The influence of the Debye length of the nanowires and the gap between electrodes in the gas sensor response is examined and discussed.

In recent years, owing to the significant applications of health monitoring, wearable electronic devices such as smart watches, smart glass and wearable cameras have been growing rapidly. Gas sensor is an important part of wearable electronic devices for detecting pollutant, toxic, and combustible gases. However, in order to apply to wearable electronic devices, the gas sensor needs flexible, transparent, and working at room temperature, which are not available for traditional gas sensors. Here, we for the first time fabricate a light-controlling, flexible, transparentand working at room-temperature ethanol gas sensor by using commercial ZnO nanoparticles. The fabricated sensor not only exhibits fast and excellent photoresponse, but also shows high sensing response to ethanol under UV irradiation. Meanwhile, its transmittance exceeds 62% in the visible spectral range, and the sensing performance keeps the same even bent it at a curvature angle of 90o. Additionally, using commercial ZnO nanoparticles provides a facile and low-cost route to fabricate wearable electronic devices.

Magnetosheath high-speed jets (HSJs) are dayside upstream transient disturbances with enhanced flow velocity and dynamic pressure. They are associated with significant magnetopause perturbations, ultralow frequency waves in the dayside magnetosphere, and localized flow enhancements in the ionosphere. However, whether HSJs have corresponding dayside aurora signatures is still an open question. If auroral signatures are found, 2-D structure and evolution of HSJ effects on the magnetosphere can be imaged in a much higher precision than possible by other means. In this study, eight HSJ events are identified by the THEMIS satellites located within ±1 MLT of the center of the field-of-view of the South Pole station all-sky imager. In all of those cases, the HSJs are observed to have a nearly one-to-one relationship with individual localized discrete/diffuse auroral brightenings. The azimuthal size of HSJ-related diffuse aurora signatures is~800 km at 230-km altitude in the ionosphere and~3.7 Re in the magnetosphere, which is slightly larger but of the order of the cross-sectional diameter of HSJs (~1 Re). Furthermore, most of those aurora signatures have azimuthal motion, whose magnitude and direction agree with magnetosheath background flows. This study for the first time shows high-resolution, two-dimensional observations of localized structure and fast propagation of precipitation due to magnetosheath HSJs. We conclude that magnetosheath HSJs can have substantial impacts on the coupled magnetosphere-ionosphere system, causing localized magnetospheric compression and aurora brightening, in a similar manner to responses during interplanetary shocks except with a smaller scale size. Recent papers show that HSJs tend to occur when the IMF cone angle is low, especially less than 40°( Plaschke et al., 2013). Hietala et al. (2009) suggested that HSJs are probably generated due to the ripples of the quasi-parallel bow shock, and a quantitative study shows that 97% of the observed HSJs can be