We report the structure, optical, and gas-sensing properties of ZnO nanorods with different diameters. Vertically well-aligned homogeneous nanorods were grown along the c-axis orientation. The shift of Raman scattering E 2 (high) mode and photoluminescence (PL) spectra were used to study the dependences of nanorod diameters on the stress and oxygen vacancy. Gas sensors were prepared and tested for the detection of C 2 H 5 OH and H 2 S (100 ppm) in air. It was found that the thin nanorods have a significantly better sensing performance than the thick nanorods. We provide a possible explanation from the aspect of the sensing mechanism of the surface reaction process.

In this letter, we present a gas sensor using a single ZnO nanowire as a sensing unit. This ZnO nanowire-based sensor has quick and high sensitive response to H2S in air at room temperature. It has also been found that the gas sensitivity of the ZnO nanowires could be modulated and enhanced by He+ implantation at an appropriate dose. A possible explanation is given based on the modulation model of the depletion layer.

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A stabilized diesel-methanol blend was realized and a study on the performance and emissions of the diesel-methanol blend was carried out in a compression ignition engine. The study showed that the engine thermal efficiency increases and the diesel equivalent b.s.f.c. decreases with increase in the oxygen mass fraction (or methanol mass fraction) of the diesel-methanol blends due to an increased fraction of premixed combustion phase, oxygen enrichment and improvement in the diffusive combustion phase. Further increase in the fuel delivery advance angle will achieve a better engine thermal efficiency when the diesel engine is operated using the diesel-methanol fuel blends. A marked reduction in the exhaust CO and smoke can be achieved when operating with the diesel-methanol blend. There is not a large variation in the exhaust hydrocarbon with the addition of methanol in diesel fuel. NOx increases with increase in the mass of methanol added; methanol addition to diesel fuel was found to have a strong influence on the NOx concentration at high engine loads rather than at low engine loads, and a flat NOx-smoke trade-offcurve exists when operating with the diesel-methanol fuel blends.