Low and high-concentration nitric wastewater can induce stable nitrite accumulation and realize the nitrification system, with the nitrite accumulation rate between 50% and 90%. In the low-concentration nitrite nitrif...Low and high-concentration nitric wastewater can induce stable nitrite accumulation and realize the nitrification system, with the nitrite accumulation rate between 50% and 90%. In the low-concentration nitrite nitrification system, the average FA concentrations during the period of stable nitrite accumulation remained at 7 to 10 mg/L. In the high-concentration nitrite nitrification system, the nitrogen oxidation activity will not be affected by biomass, the nitrite oxidation activity is related to the system biomass, it is recommended to be measured by FA/MLSS. Keeping the FA sludge load below 0.1 is the precondition of making good nitrite accumulation and nitrogen degradation rate. Nitrite oxidation bacteria cannot be totally eliminated or washed out from the system.展开更多
Seedlings of drought-tolerance rice varieties Han 501and Han A03,and the drought sensitive varietiesNanjing 11 and Yanjing 2 were raised in a paddyfield and transplanted into pots at the age of 8leaves.Water stress st...Seedlings of drought-tolerance rice varieties Han 501and Han A03,and the drought sensitive varietiesNanjing 11 and Yanjing 2 were raised in a paddyfield and transplanted into pots at the age of 8leaves.Water stress started at the tillering stage byholding water from 0 MPa of the soil water potentialin pots till the leaves showed seriously wilting.展开更多
Microdamage accumulation in bone is one of the mechanisms for energy dissipation during the fracture process. Changes in the ultrastructure and composition of bone constituents due to aging or diseases could affect mi...Microdamage accumulation in bone is one of the mechanisms for energy dissipation during the fracture process. Changes in the ultrastructure and composition of bone constituents due to aging or diseases could affect microdamage accumulation. Low concentration （1 mM） of sodium fluoride （NaF） has been used in this study to investigate the effect of ultrastructural changes on microdamage accumu- lation in mouse tibias following free-fall impact loadings. Twenty-two tibias were divided randomly into control and NaF-treated groups. Free-fall impact loading was conducted twice on each tibia to produce microdamage. The elas- tic modulus of NaF-treated tibias decreased significantly after the impact loadings, while there was no significant difference in the modulus of untreated samples between pre- and post-damage loadings. Microdamage morphology analysis showed that less and shorter microcracks existed in NaF-treated tibias compared with control bones. Meanwhile, more and longer microcracks were observed in tensile regions in untreated samples compared with that in compressive regions, whereas no significant difference was observed between tensile and compressive regions in NaF-treated bones. The results of this study indicate that more energy is required to generate microcracks in NaF-treated bone than in normal bone. A low concentration of fluoride treatment may increase the toughness of bone under impact loading.展开更多
基金supported by Guizhou Science and Technology Fund Project 2008-2236the Scientific and Technological Project under Science and Technology Department of Guizhou Province [SZ(2008)3073]Guizhou University’s Scientific Research Personnel Introduction Pro-gram 2008-029
文摘Low and high-concentration nitric wastewater can induce stable nitrite accumulation and realize the nitrification system, with the nitrite accumulation rate between 50% and 90%. In the low-concentration nitrite nitrification system, the average FA concentrations during the period of stable nitrite accumulation remained at 7 to 10 mg/L. In the high-concentration nitrite nitrification system, the nitrogen oxidation activity will not be affected by biomass, the nitrite oxidation activity is related to the system biomass, it is recommended to be measured by FA/MLSS. Keeping the FA sludge load below 0.1 is the precondition of making good nitrite accumulation and nitrogen degradation rate. Nitrite oxidation bacteria cannot be totally eliminated or washed out from the system.
文摘Seedlings of drought-tolerance rice varieties Han 501and Han A03,and the drought sensitive varietiesNanjing 11 and Yanjing 2 were raised in a paddyfield and transplanted into pots at the age of 8leaves.Water stress started at the tillering stage byholding water from 0 MPa of the soil water potentialin pots till the leaves showed seriously wilting.
基金supported by the National Natural Science Foundation of China (Grant 10872007)
文摘Microdamage accumulation in bone is one of the mechanisms for energy dissipation during the fracture process. Changes in the ultrastructure and composition of bone constituents due to aging or diseases could affect microdamage accumulation. Low concentration （1 mM） of sodium fluoride （NaF） has been used in this study to investigate the effect of ultrastructural changes on microdamage accumu- lation in mouse tibias following free-fall impact loadings. Twenty-two tibias were divided randomly into control and NaF-treated groups. Free-fall impact loading was conducted twice on each tibia to produce microdamage. The elas- tic modulus of NaF-treated tibias decreased significantly after the impact loadings, while there was no significant difference in the modulus of untreated samples between pre- and post-damage loadings. Microdamage morphology analysis showed that less and shorter microcracks existed in NaF-treated tibias compared with control bones. Meanwhile, more and longer microcracks were observed in tensile regions in untreated samples compared with that in compressive regions, whereas no significant difference was observed between tensile and compressive regions in NaF-treated bones. The results of this study indicate that more energy is required to generate microcracks in NaF-treated bone than in normal bone. A low concentration of fluoride treatment may increase the toughness of bone under impact loading.
