Optimal management of air quality in pig confinement buildings is essential for both hygienic and environmental aspects of pig production. The exposure level of farmers and pigs to aerial contaminants and correlations between environmental variables were evaluated in pig confinement buildings (piggeries). We evaluated the following aerial contaminants: (1) odor concentration index and the gaseous compounds ammonia and hydrogen sulfide, (2) total dust and respirable dust, and (3) microbes, comprising total bacteria, fungi, and gram-negative bacteria. The data presented in the study were collected over 30 days, with sampling once every three days from April to June in 2005. Although the concentrations of all the aerial contaminants except for respirable dust and ammonia were higher in the breathing zone of the pigs than in that of farmers, the only significant differences found between farmers' and pigs' breathing zones were in total dust and hydrogen sulfide. In contrast, ammonia concentration was significantly higher in the farmers' breathing zone than the pigs' (p < 0.05). Total dust significantly correlated with all the environmental variables except for respirable dust and inside temperature. Relative humidity, rather than temperature, was the main environmental factor affecting fluctuations of aerial contaminants in the pig confinement buildings (p < 0.05).

We have investigated the structural and optical properties of Ga-doped ZnO films grown on GaN templates by plasma-assisted molecular-beam epitaxy. The carrier concentration in Ga-doped ZnO films can be controlled from 1.33×1018/cm3 to 1.13×1020/cm3. Despite high Ga incorporation, the linewidth of (0002) ω-rocking curves of Ga-doped ZnO films still lies in the range from 5 to 15 arc min. Photoluminescence (PL) spectra of Ga-doped ZnO films show dominant near-bandedge emission with negligibly weak deep-level emission, independent of carrier concentration. The PL spectrum exhibits a new emission line at 3.358 eV, which corresponds to exciton emission bound to a Ga donor. To avoid degradation of the PL intensity, the maximum dopability of Ga in ZnO is determined to be around 2.6×1019/cm3.

Surface-architecture-controlled ZnO nanowires were grown using a vapor transport method on various ZnO buffer film coated c-plane sapphire substrates with or without Au catalysts. The ZnO nanowires that were grown showed two different types of geometric properties: corrugated ZnO nanowires having a relatively smaller diameter and a strong deep-level emission photoluminescence (PL) peak and smooth ZnO nanowires having a relatively larger diameter and a weak deep-level emission PL peak. The surface morphology and size-dependent tunable electronic transport properties of the ZnO nanowires were characterized using a nanowire field effect transistor (FET) device structure. The FETs made from smooth ZnO nanowires with a larger diameter exhibited negative threshold voltages, indicating n-channel depletion-mode behavior, whereas those made from corrugated ZnO nanowires with a smaller diameter had positive threshold voltages, indicating n-channel enhancement-mode behavior.