Based on the achievement of synthesis of ZnO nanowires in mass production, ZnO nanowires gas sensors were fabricated with microelectromechanical system technology and ethanol-sensing characteristics were investigated. The sensor exhibited high sensitivity and fast response to ethanol gas at a work temperature of 300 °C. Our results demonstrate the potential application of ZnO nanowires for fabricating highly sensitive gas sensors.

The mechanism of CO 2 dissociation during entry in the Mars atmosphere is experimentally investigated. A hydrogen-oxygen combustion-driven shock tube is used to simulate physical and chemical conditions in a CO 2-N 2 mixture. Two shock velocity/initial pressure conditions are studied: 7.09 0.05 km∕s at 100 Pa (called the low-pressure condition) and 5.68 0.07 km∕s at 300 Pa (called the high-pressure condition). The temperature behind the shock wave is obtained by analyzing the high-temporal-resolution and high-spatial-resolution experimental spectra of the CN violet (B 2 Σ → X 2 Σ , Δv 0) system. The CO number density is derived using a tunable diode laser absorption spectroscopy system based on CO absorption near 2.33 μm. Moreover, a numerical code is developed to reproduce the experimental results (temperatures and species densities). The kinetic code in this work is based on Park's two-temperature model. Comparisons between experiments and calculations are presented. Such a relatively simple two-temperature model fails to accurately describe the nonequilibrium temperature and CO number density but is suitable for equilibrium temperature predictions.