The advanced hot-rolled transformation induced plasticity （TRIP） steel with high tensile strength of 775 MPa, high elongation of 29% and low ductile-brittle transmission temperature less than -80℃ has been develope...The advanced hot-rolled transformation induced plasticity （TRIP） steel with high tensile strength of 775 MPa, high elongation of 29% and low ductile-brittle transmission temperature less than -80℃ has been developed in laboratory based on the common silicon and manganese chemical composition. The experimental results showed that the microstructures were featured with ultra fine grain size less than 5μm, appropriate retained austenite volume fraction around 11.8% and purified ferrite grain, which may result in well balanced mechanical properties for the steel.展开更多
The concentration and spatial distribution of persistent toxic substances （PTS） in the river sediment in Chaohu City, China were investigated. A total of nine surface sediments were collected and the selected PTS po...The concentration and spatial distribution of persistent toxic substances （PTS） in the river sediment in Chaohu City, China were investigated. A total of nine surface sediments were collected and the selected PTS pollutants including six heavy metals and nineteen polybrominated diphenyl ethers （PBDEs） were analyzed. The mean heavy metal concentrations （in mg/kg, dry weight） ranged within 0.18-1.53 （Fig）, 50.08-200.18 （Cu）, 118.70-313.65 （Zn）, 50,77-310,85 （Cr）, 37.12-92.72 （Pb） and 13.29-197.24 （As）, and Cu, Zn and As have been regarded as the main metal pollutants, The levels of PBDEs （1.2-12.1 ng/g） and BDE-209 （2.4--30.5 ng/g） were at the middle level of the global range. BDE-209 was the predominant congener （67.0%-85.7%）, which agrees with the fact that technical deca-BDE mixtures are the dominant PBDE formulation in China. The relative high level of PTS poUutants in the western part of the city is probably owing to the intensive agricultural activities and lack of sewerage system there. The ecological risk assessment with the sediment quality guidelines （$OGs） indicates that the urban river sediments in the city have been heavily contaminated by heavy metals with probable ecotoxicological impacts on freshwater organisms and the main toxic pollutants are Hg and As, The results of current study imply that the city, and perhaps many other small cities in China as well, requires immediate pollution control measures with emphasis on not only conventional organic pollutants but also on PTS such as heavy metals and PBDEs.展开更多
Nb-Tihot-rolled TRIP-assisted steel with high plasticity and appropriate volume percentage of retained austenite based on fine ferrite grain have been developed in the experiment. The test results showed that niobium ...Nb-Tihot-rolled TRIP-assisted steel with high plasticity and appropriate volume percentage of retained austenite based on fine ferrite grain have been developed in the experiment. The test results showed that niobium tend to exist in solution state in matrix with less precipitation, and niobium-titanium could be precipitated in form of （Nb, Ti）C or （Nb, Ti） （C, N）, which play an important role in increasing yield strength （from 495 MPa to 610 MPa）. Besides, the retained austenite had a positive effect on improving the plasticity by transformation into martensite during tensile deformation.展开更多
文摘The advanced hot-rolled transformation induced plasticity （TRIP） steel with high tensile strength of 775 MPa, high elongation of 29% and low ductile-brittle transmission temperature less than -80℃ has been developed in laboratory based on the common silicon and manganese chemical composition. The experimental results showed that the microstructures were featured with ultra fine grain size less than 5μm, appropriate retained austenite volume fraction around 11.8% and purified ferrite grain, which may result in well balanced mechanical properties for the steel.
基金supported by the National Key Technology R&D Program in the 12th Five-Year Plan of China:Research & Development on Suitable Key Technologies of the Village Environmental Monitoring of China (No.2012BAJ24B01)
文摘The concentration and spatial distribution of persistent toxic substances （PTS） in the river sediment in Chaohu City, China were investigated. A total of nine surface sediments were collected and the selected PTS pollutants including six heavy metals and nineteen polybrominated diphenyl ethers （PBDEs） were analyzed. The mean heavy metal concentrations （in mg/kg, dry weight） ranged within 0.18-1.53 （Fig）, 50.08-200.18 （Cu）, 118.70-313.65 （Zn）, 50,77-310,85 （Cr）, 37.12-92.72 （Pb） and 13.29-197.24 （As）, and Cu, Zn and As have been regarded as the main metal pollutants, The levels of PBDEs （1.2-12.1 ng/g） and BDE-209 （2.4--30.5 ng/g） were at the middle level of the global range. BDE-209 was the predominant congener （67.0%-85.7%）, which agrees with the fact that technical deca-BDE mixtures are the dominant PBDE formulation in China. The relative high level of PTS poUutants in the western part of the city is probably owing to the intensive agricultural activities and lack of sewerage system there. The ecological risk assessment with the sediment quality guidelines （$OGs） indicates that the urban river sediments in the city have been heavily contaminated by heavy metals with probable ecotoxicological impacts on freshwater organisms and the main toxic pollutants are Hg and As, The results of current study imply that the city, and perhaps many other small cities in China as well, requires immediate pollution control measures with emphasis on not only conventional organic pollutants but also on PTS such as heavy metals and PBDEs.
文摘Nb-Tihot-rolled TRIP-assisted steel with high plasticity and appropriate volume percentage of retained austenite based on fine ferrite grain have been developed in the experiment. The test results showed that niobium tend to exist in solution state in matrix with less precipitation, and niobium-titanium could be precipitated in form of （Nb, Ti）C or （Nb, Ti） （C, N）, which play an important role in increasing yield strength （from 495 MPa to 610 MPa）. Besides, the retained austenite had a positive effect on improving the plasticity by transformation into martensite during tensile deformation.
