A two-stage upflow anaerobic sludge blanket （UASB） and sequencing batch reactor （SBR） system was introduced to treat landfill leachate for advanced removal of COD and nitrogen at low temperature. In order to impro...A two-stage upflow anaerobic sludge blanket （UASB） and sequencing batch reactor （SBR） system was introduced to treat landfill leachate for advanced removal of COD and nitrogen at low temperature. In order to improve the total nitrogen （TN） removal efficiency and to reduce the COD requirement for denitrification, the raw leachate with recycled SBR nitrification supematant was pumped into the first-stage UASB （UASB1） to achieve simultaneous denitrification and methanogenesis. The results showed that UASB1 played an important role in COD removal and UASB2 and SBR further enhanced the nutrient removal efficiency. When the organic loading rates of UASB1, UASB2 and SBR were 11.95, 1.63 and 1.29 kg COD/（m^3.day）, respectively, the total COD removal efficiency of the whole system reached 96.7%. The SBR acted as the real undertaker for NH4^＋-N removal due to aerobic nitrification. The system obtained about 99.7% of NH4^＋-N removal efficiency at relatively low temperature （14.9-10.9℃）. More than 98.3% TN was removed through complete denitrification in UASB 1 and SBR. In addition, temperature had a significant effect on the rates of nitrification and denitrification rather than the removal of TN and NH4^＋-N once the complete nitrification and denitrification were achieved.展开更多
To investigate the soybean (Glycine max Merr.) wet endurance, and the affect of the maturity and the ambient temperature to the response, the plantlet in growth stage ranged from R1 to R2 of 8 Japanese soybean cultiva...To investigate the soybean (Glycine max Merr.) wet endurance, and the affect of the maturity and the ambient temperature to the response, the plantlet in growth stage ranged from R1 to R2 of 8 Japanese soybean cultivars which characterized as various wet endurance in a past report were cultured under hypoxic-hydroponic condition for a month. Two experiments at different periods differed significantly in temperature of air and hydroponic solution, but the oxygenic condition were similar each experiments, as aimed for. And also, control and hypoxia treatments significantly differed in dissolved oxygenic concentration in each experiments. The hypoxic condition at higher temperature induced the reduction of survival of plantlet up to 70%. At higher temperature, the survival rate of late maturity types “Yuzuru” and “Shirotsurunoko” were decreased significantly in hypoxic condition than in control. Similarly, the shoot dry matters of them were also decreased significantly in hypoxia at higher temperature. The tendency of the decreasing in hypoxia was remarkable in the pod dry matter, and the symptoms were shown also at the lower temperature. From these results, soybean’s hypoxic tolerant may be reflected with the wet endurance, the process of hypoxic damages can be divided to sudden death symptom and biomass decreasing, and the mechanisms of hypoxic tolerance might be affected strongly by ambient temperature, and absolutely controlled with the genetic background.展开更多
Crystalline and nanostructured cobalt （CoFe2O4）, nickel （NiFe2O4）, zinc （ZnFe2O4） and manganese （MnFe2O4） spinel ferrites are synthesized with high yields, crystallinity and purity through an easy, quick, repr...Crystalline and nanostructured cobalt （CoFe2O4）, nickel （NiFe2O4）, zinc （ZnFe2O4） and manganese （MnFe2O4） spinel ferrites are synthesized with high yields, crystallinity and purity through an easy, quick, reproducible and low-temperature hydrothermal assisted route starting from an aqueous suspension of copredpitated metal oxalates. The use of water as a reaction medium is a further advantage of the chosen protocol. Additionally, the zinc spinel is also prepared through an alternative route combining copredpitation of oxalates from an aqueous solution with thermal decomposition under reflux conditions. The nanocrystalline powders are obtained as a pure crystalline phase already at the extremely low tem- perature of 75 ℃ and no further thermal treatment is needed. The structure and microstructure of the prepared materials is investigated by means of X-ray powder diffraction （XRPD）, while X-ray photoelectron spectroscopy （XPS） and inductively coupled plasma-atomic emission spectroscopy （ICP-AES） analyses are used to gain information about the surface and bulk composition of the samples, respectively, confirming the expected stoichiometry. To investigate the effect of the synthesis protocol on the morphology of the obtained ferrites, transmission electron microscopy （TEM） observations are performed on selected samples. The magnetic properties of the cobalt and manganese spinels are also investigated using a superconducting quantum device magnetometer （SQUID） revealing hard and soft ferrimagnetic behavior, respectively.展开更多
基金supported by the National Natural Science Foundation of China (No.50978003)the Beijing Natural Science Foundation (No.8091001)+1 种基金the Funding Project for Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality (No.PHR20090502)the State Key Laboratory of Urban Water Resource and Environment (No.QAK200802)
文摘A two-stage upflow anaerobic sludge blanket （UASB） and sequencing batch reactor （SBR） system was introduced to treat landfill leachate for advanced removal of COD and nitrogen at low temperature. In order to improve the total nitrogen （TN） removal efficiency and to reduce the COD requirement for denitrification, the raw leachate with recycled SBR nitrification supematant was pumped into the first-stage UASB （UASB1） to achieve simultaneous denitrification and methanogenesis. The results showed that UASB1 played an important role in COD removal and UASB2 and SBR further enhanced the nutrient removal efficiency. When the organic loading rates of UASB1, UASB2 and SBR were 11.95, 1.63 and 1.29 kg COD/（m^3.day）, respectively, the total COD removal efficiency of the whole system reached 96.7%. The SBR acted as the real undertaker for NH4^＋-N removal due to aerobic nitrification. The system obtained about 99.7% of NH4^＋-N removal efficiency at relatively low temperature （14.9-10.9℃）. More than 98.3% TN was removed through complete denitrification in UASB 1 and SBR. In addition, temperature had a significant effect on the rates of nitrification and denitrification rather than the removal of TN and NH4^＋-N once the complete nitrification and denitrification were achieved.
文摘To investigate the soybean (Glycine max Merr.) wet endurance, and the affect of the maturity and the ambient temperature to the response, the plantlet in growth stage ranged from R1 to R2 of 8 Japanese soybean cultivars which characterized as various wet endurance in a past report were cultured under hypoxic-hydroponic condition for a month. Two experiments at different periods differed significantly in temperature of air and hydroponic solution, but the oxygenic condition were similar each experiments, as aimed for. And also, control and hypoxia treatments significantly differed in dissolved oxygenic concentration in each experiments. The hypoxic condition at higher temperature induced the reduction of survival of plantlet up to 70%. At higher temperature, the survival rate of late maturity types “Yuzuru” and “Shirotsurunoko” were decreased significantly in hypoxic condition than in control. Similarly, the shoot dry matters of them were also decreased significantly in hypoxia at higher temperature. The tendency of the decreasing in hypoxia was remarkable in the pod dry matter, and the symptoms were shown also at the lower temperature. From these results, soybean’s hypoxic tolerant may be reflected with the wet endurance, the process of hypoxic damages can be divided to sudden death symptom and biomass decreasing, and the mechanisms of hypoxic tolerance might be affected strongly by ambient temperature, and absolutely controlled with the genetic background.
文摘Crystalline and nanostructured cobalt （CoFe2O4）, nickel （NiFe2O4）, zinc （ZnFe2O4） and manganese （MnFe2O4） spinel ferrites are synthesized with high yields, crystallinity and purity through an easy, quick, reproducible and low-temperature hydrothermal assisted route starting from an aqueous suspension of copredpitated metal oxalates. The use of water as a reaction medium is a further advantage of the chosen protocol. Additionally, the zinc spinel is also prepared through an alternative route combining copredpitation of oxalates from an aqueous solution with thermal decomposition under reflux conditions. The nanocrystalline powders are obtained as a pure crystalline phase already at the extremely low tem- perature of 75 ℃ and no further thermal treatment is needed. The structure and microstructure of the prepared materials is investigated by means of X-ray powder diffraction （XRPD）, while X-ray photoelectron spectroscopy （XPS） and inductively coupled plasma-atomic emission spectroscopy （ICP-AES） analyses are used to gain information about the surface and bulk composition of the samples, respectively, confirming the expected stoichiometry. To investigate the effect of the synthesis protocol on the morphology of the obtained ferrites, transmission electron microscopy （TEM） observations are performed on selected samples. The magnetic properties of the cobalt and manganese spinels are also investigated using a superconducting quantum device magnetometer （SQUID） revealing hard and soft ferrimagnetic behavior, respectively.
