Response surface methodology was used to optimize a medium for a red-pigmented marine bacterium S-9801 strain （Flavobocterium sp.）. In the first optimization step the influence of yeast extract, peptone, glucose and...Response surface methodology was used to optimize a medium for a red-pigmented marine bacterium S-9801 strain （Flavobocterium sp.）. In the first optimization step the influence of yeast extract, peptone, glucose and sodium chloride on pigment production was evaluated using a fractional factorial design. Pigment production was positively influenced by glucose and sodium chloride while other components had no significant effect. In the second step the path of steepest ascent was used to approach the optimal region of the medium composition. In the third step the optimal concentration of glucose and sodium chloride was determined by a central composite design and response analysis. The optimized medium allowed pigment production （A 535-650） to be increased from 0.137 to 0.559, being 320% higher than the original medium.展开更多
The beginning of October is the high occurrence period of straw burning in North China and Jianghuai region. Heavy pollution weather caused by straw burning often takes place in recent two years,and thus human factor ...The beginning of October is the high occurrence period of straw burning in North China and Jianghuai region. Heavy pollution weather caused by straw burning often takes place in recent two years,and thus human factor increases the unpredictability of the air quality forecast. In the early autumn of 2015,a continuous fog-haze weather and heavy air pollution event occurred in North China and Jianghuai region due to the straw burning. In this paper,the effect of straw burning on air quality under the same adverse diffusive meteorological conditions has been analyzed by using the ground and upper air meteorological observation data and air quality monitoring data of Environmental Protection Agency in recent two years. The comparison results show that the basic conditions of heavy pollution are weak wind and the unfavorable diffusion situation. In contrast,relative humidity is the key factor,only 40% of relative humidity during the straw burning can reach heavy pollution level during no straw burning.展开更多
The concentration and the enrichment factors of mercury (Hg) in the sediment cores of Dongjiu and Xijiu, Taihu Lake catchment, were studied. The accumulation fluxes, anthropogenic input concentration and anthropogenic...The concentration and the enrichment factors of mercury (Hg) in the sediment cores of Dongjiu and Xijiu, Taihu Lake catchment, were studied. The accumulation fluxes, anthropogenic input concentration and anthropogenic accumulation fluxes of Hg in recent 100 years were also analyzed based on the 210Pb dating. The results indicate that the increasing concentrations of Hg in the sediments are influ-enced by natural factors and anthropogenic input simultaneously. Generally, about 2/3 of the Hg in the sediment was from anthropogenic sources. In the early 20th century, the anthropogenic input was owing to the urban development and fossil fuel consumptions surrounding the Taihu Lake and the worldwide atmospheric deposition of Hg since the industrial revolution. The concentration and an-thropogenic fluxes of Hg increased with the industrial development in the catchment since the 1930s. It reached the maximum during the middle 1970s and middle 1990s, and decreased since the middle 1990s with constraints on high pollution industries.展开更多
文摘Response surface methodology was used to optimize a medium for a red-pigmented marine bacterium S-9801 strain （Flavobocterium sp.）. In the first optimization step the influence of yeast extract, peptone, glucose and sodium chloride on pigment production was evaluated using a fractional factorial design. Pigment production was positively influenced by glucose and sodium chloride while other components had no significant effect. In the second step the path of steepest ascent was used to approach the optimal region of the medium composition. In the third step the optimal concentration of glucose and sodium chloride was determined by a central composite design and response analysis. The optimized medium allowed pigment production （A 535-650） to be increased from 0.137 to 0.559, being 320% higher than the original medium.
基金Supported by Scientific Technology Item of State Grid Corporation of China(52010115002P)
文摘The beginning of October is the high occurrence period of straw burning in North China and Jianghuai region. Heavy pollution weather caused by straw burning often takes place in recent two years,and thus human factor increases the unpredictability of the air quality forecast. In the early autumn of 2015,a continuous fog-haze weather and heavy air pollution event occurred in North China and Jianghuai region due to the straw burning. In this paper,the effect of straw burning on air quality under the same adverse diffusive meteorological conditions has been analyzed by using the ground and upper air meteorological observation data and air quality monitoring data of Environmental Protection Agency in recent two years. The comparison results show that the basic conditions of heavy pollution are weak wind and the unfavorable diffusion situation. In contrast,relative humidity is the key factor,only 40% of relative humidity during the straw burning can reach heavy pollution level during no straw burning.
基金the National Natural Science Foundation of China (Grant No. 40772203)Chinese Academy of Sciences (Grant No. KZCX2-YW-319)the Chinese National Key Basic Research Project (Grant No. 2002CB412303)
文摘The concentration and the enrichment factors of mercury (Hg) in the sediment cores of Dongjiu and Xijiu, Taihu Lake catchment, were studied. The accumulation fluxes, anthropogenic input concentration and anthropogenic accumulation fluxes of Hg in recent 100 years were also analyzed based on the 210Pb dating. The results indicate that the increasing concentrations of Hg in the sediments are influ-enced by natural factors and anthropogenic input simultaneously. Generally, about 2/3 of the Hg in the sediment was from anthropogenic sources. In the early 20th century, the anthropogenic input was owing to the urban development and fossil fuel consumptions surrounding the Taihu Lake and the worldwide atmospheric deposition of Hg since the industrial revolution. The concentration and an-thropogenic fluxes of Hg increased with the industrial development in the catchment since the 1930s. It reached the maximum during the middle 1970s and middle 1990s, and decreased since the middle 1990s with constraints on high pollution industries.
