Factors on degradation of chlorothalonil(CLT) in water by high frequency ultrasonic irradiation were investigated.The effects of initial concentration of chlorothalonil,dosages of tertiary butyl alcohol,humic acid and...Factors on degradation of chlorothalonil(CLT) in water by high frequency ultrasonic irradiation were investigated.The effects of initial concentration of chlorothalonil,dosages of tertiary butyl alcohol,humic acid and initial pH value on degradation of chlorothalonil,as well as the reaction mechanism were studied.The results reveal that chlorothalonil could be effectively degradated by ultrasonic irradiation.The reaction constant value kapp decreased from 0.014 1 to 0.010 2 min-1 with the initial concentration increasing from 50 to 400 μg/L during 180 min irradiation.Tertiary butyl alcohol had negative effect on chlorothalonil degradation,while lower concentration of humic acid promoted the sonolysis,and kapp declined with the further concentration increasing.The kapp varied little when the pH value ranged from 3.10 to 10.28.It may be concluded that mechanical and pyrolysis process played main roles on the degradation of chlorothalonil in ultrasonic irradiation rather than ·OH attack.The electrical energy per order(EEo) values for sonolysis degradation of CLT were also calculated to evaluate the cost of the process.展开更多
The central buckle, which is often used in a suspension bridge, can improve bridges' performance in the actual operation condition. The influence of the central buckle on natural vibration characteristics and brid...The central buckle, which is often used in a suspension bridge, can improve bridges' performance in the actual operation condition. The influence of the central buckle on natural vibration characteristics and bridge-deck driving comfort of a long-span suspension bridge is studied by using a case study of Siduhe Suspension Bridge in China. Based on the finite element software ANSYS and independently complied program, the influence of the central buckle on the structure force-applied characteristics of a long-span suspension bridge has been explored. The results show that the huge increases of natural frequencies can result in the presence of central buckles because of the increases of bending and torsional rigidities. The central buckle basically makes the stiffening girders and cables within the triangular area covered as a relatively approximate rigid area. Hence, the central buckle can reduce the torsional displacement of the main girder. However, the increases of bending and torsional rigidities have little influence on the impact factor, which is obtained by using vehicle-bridge coupled vibration analysis. This means that the central buckle has little effect on the comfort indices. In addition, it is found that the central buckle can enhance the bridge deck's driving stability due to the decrease of the torsional displacements of the main girder.展开更多
基金Project(2008ZX07421-002) supported by the National Major Project of Science & Technology Ministry of ChinaProject(2008AA06A412) supported by the National High Technology Research and Development Program of ChinaProject(20009-K7-4) supported by the Research and Development of Ministry of Housing and Urban-Rural Development of China
文摘Factors on degradation of chlorothalonil(CLT) in water by high frequency ultrasonic irradiation were investigated.The effects of initial concentration of chlorothalonil,dosages of tertiary butyl alcohol,humic acid and initial pH value on degradation of chlorothalonil,as well as the reaction mechanism were studied.The results reveal that chlorothalonil could be effectively degradated by ultrasonic irradiation.The reaction constant value kapp decreased from 0.014 1 to 0.010 2 min-1 with the initial concentration increasing from 50 to 400 μg/L during 180 min irradiation.Tertiary butyl alcohol had negative effect on chlorothalonil degradation,while lower concentration of humic acid promoted the sonolysis,and kapp declined with the further concentration increasing.The kapp varied little when the pH value ranged from 3.10 to 10.28.It may be concluded that mechanical and pyrolysis process played main roles on the degradation of chlorothalonil in ultrasonic irradiation rather than ·OH attack.The electrical energy per order(EEo) values for sonolysis degradation of CLT were also calculated to evaluate the cost of the process.
基金Project(2015CB057701)supported by the National Basic Research Program of ChinaProjects(51308071,51378081)supported by the National Natural Science Foundation of China+2 种基金Project(3JJ4057)supported by the Natural Science Foundation of Hunan Province,ChinaProject(12K076)supported by the Open Fund of Innovation Platform in Hunan Provincial Universities,ChinaProject(2015319825120)supported by the Traffic Department of Appliced Basic Research,China
文摘The central buckle, which is often used in a suspension bridge, can improve bridges' performance in the actual operation condition. The influence of the central buckle on natural vibration characteristics and bridge-deck driving comfort of a long-span suspension bridge is studied by using a case study of Siduhe Suspension Bridge in China. Based on the finite element software ANSYS and independently complied program, the influence of the central buckle on the structure force-applied characteristics of a long-span suspension bridge has been explored. The results show that the huge increases of natural frequencies can result in the presence of central buckles because of the increases of bending and torsional rigidities. The central buckle basically makes the stiffening girders and cables within the triangular area covered as a relatively approximate rigid area. Hence, the central buckle can reduce the torsional displacement of the main girder. However, the increases of bending and torsional rigidities have little influence on the impact factor, which is obtained by using vehicle-bridge coupled vibration analysis. This means that the central buckle has little effect on the comfort indices. In addition, it is found that the central buckle can enhance the bridge deck's driving stability due to the decrease of the torsional displacements of the main girder.
