The purpose of this study was to investigate the mediating effect of grades, positions, and match results in the causal relationships between achievement-goal orientation and sport flow among middle and high school soccer players. The total data of 448 copies were collected from middle and high school soccer teams while 405 copies were accepted for final analysis without 43, and multi-group confirmatory factor analysis was conducted to the data. The result of latent mean analysis showed that middle school players had significantly higher mean in sense of control of sport flow and transformation of time, and defenders showed significantly higher than offenders in ego orientation and transformation of time, while winning group achieved significantly higher than losing group in all factors except ecstasy. Also multi-group analysis showed that achievement-goal orientation had significant effect on sport flow in middle and high school players, and middle school players had more powerful effect than high school players. Meanwhile, the achievement-goal orientation affected significantly on sport flow in offenders and defenders, and ego orientation of offenders affects on sport flow. task orientation of winning and losing groups had significant effect on sport flow, and ego orientation of winning group showed significant effect on sport flow.

A fixed biofilm reactor system composed of anaerobic, anoxic(1), anoxic(2), aerobic(1) and aerobic(2) reactor was packed with synthetic activated ceramic (SAC) media and adopted to reduce the inhibition effect of low temperature on nitrification activities. The changes of nitrification activity at different wastewater temperature were investigated through the evaluation of temperature coefficient, volatile attached solid (VAS), specific nitrification rate and alkalinity consumption. Operating temperature was varied from 20 to 5 ℃. In this biofilm system, the specific nitrification rates of 15 ℃, 10 ℃ and 5 ℃ were 0.972, 0.859 and 0.613 when the specific nitrification rate of 20 ℃ was assumed to 1.00. Moreover the nitrification activity was also observed at 5 ℃ which is lower temperature than the critical temperature condition for the microorganism of activated sludge system. The specific amount of volatile attached solid (VAS) on media was maintained the range of 13.6-12.5 mg VAS/g media at 20~10 ℃. As the temperature was downed to 5 ℃, VAS was rapidly decreased to 10.9 mg VAS/g media and effluent suspended solids was increased from 3.2 mg/L to 12.0 mg/L due to the detachment of microorganism from SAC media. And alkalinity consumption was lower than theoretical value with 5.23 mg as CaCO3/mg NH4 +-N removal at 20 ℃. Temperature coefficient (θ) of nitrification rate (20 ℃ ~ 5 ℃) was 1.033. Therefore, this fixed film nitrogen removal process showed superior stability for low temperature condition than conventional suspended growth process.