Some enzymatic activities were determined in the areas polluted by tailings from Tiantai Pb-Zn-Ag Mine in Zhejiang Province of China. The results indicated the soil enzymatic activities decreased significantly with in...Some enzymatic activities were determined in the areas polluted by tailings from Tiantai Pb-Zn-Ag Mine in Zhejiang Province of China. The results indicated the soil enzymatic activities decreased significantly with increase of concentrations of heavy metals or the distance away from mining tailing center, especially dehydrogenase and urease activities. Multivariate regression analysis between heavy metal contents and soil enzymatic activities indicated that single dehydrogenase activity was very significantly correlated to combined effect of soil heavy metals in mine area. Moreover, single urease, protease and acid phosphatase activities were significantly related to the combined effect of heavy metals. The results suggest it is feasible to use soil enzymatic activities to indicate the pollution situation by combined heavy metals in the soil of mine area.展开更多
The intensive management practices in greenhouse production may alter the soil physicochemical properties and contribute to the accumulation of heavy metals(HMs). To determine the HM concentrations in vegetable soil i...The intensive management practices in greenhouse production may alter the soil physicochemical properties and contribute to the accumulation of heavy metals(HMs). To determine the HM concentrations in vegetable soil in relation to soil physicochemical properties and cultivation age, we conducted a soil survey for typical greenhouse soils in Shouguang, China. The results indicated that Cd is a major HM pollutant in the tested soils, as the only HM element exceeding the allowed limit for vegetable soil. The surveyed data was analyzed with regression analysis, correlation analysis and canonical correspondence analysis(CCA). A positive correlation is observed between HM pollution level and cultivation age. CCA results suggest that the HM pollution level and distribution in soil are significantly affected by soil physicochemical properties, which was a function of years of cultivation as revealed by regression analysis. In summary, cultivation age is an important factor to affect soil physicochemical properties(organic matter and inorganic nutrients) as well as HM contamination.展开更多
The mechanism of interaction relation between the rare-earth element Ce and elements Pb and Bi in Ag-based filler metal has been studied. The results show that the compounds CePb and CeBi with high melting point can b...The mechanism of interaction relation between the rare-earth element Ce and elements Pb and Bi in Ag-based filler metal has been studied. The results show that the compounds CePb and CeBi with high melting point can be easily produced between these three elements in the filler metal, which greatly limited the formation of the isolated phase Pb or Bi and also eliminated the bad effect of impurity elements Pb and Bi on the spreading property of Ag-based filler metal. The metallurgical and quantum-mechanical bond formation analysis show that a strong chemical affinity was existed between the rare-earth element Ce and impurity elements Pb and Bi, which was proved by the XRD analysis results.展开更多
In this work,the sandwich joints were joined by low temperature pressureless sintering Ag paste.The morphology and thermal behavior of Ag nanoparticle paste was characterized and analyzed.The sintered Ag joints with d...In this work,the sandwich joints were joined by low temperature pressureless sintering Ag paste.The morphology and thermal behavior of Ag nanoparticle paste was characterized and analyzed.The sintered Ag joints with different metallization were prepared and tested.The joints with Ag metallization exhibited superior shear strength and interface bonding ratio.However,the joints with Cu metallization showed lowest shear strength and interface delamination.The interfacial microstructures were observed and the diffusion kinetics between Ag and Au atoms were both calculated.The excessive diffusion of Ag atoms towards the Au layer deteriorated the interface bonding ratio and shear strength.This work will help understand the bonding mechanism between sintered Ag and other metallization.展开更多
Objective The Songpan-Garze Fold Belt(SGFB),located in the eastern part of the Tibet Plateau and west of the Sichuan Basin,is an important pegmatite province in China.Some famous pegmatite type deposits occur in the S...Objective The Songpan-Garze Fold Belt(SGFB),located in the eastern part of the Tibet Plateau and west of the Sichuan Basin,is an important pegmatite province in China.Some famous pegmatite type deposits occur in the SGFB,including the Xuebaoding,Jiajika,Keeryin rare metal deposits and Danba muscovite deposit(Li Jiankang et al.,2015).The newly discovered super-large Lijiagou展开更多
文摘Some enzymatic activities were determined in the areas polluted by tailings from Tiantai Pb-Zn-Ag Mine in Zhejiang Province of China. The results indicated the soil enzymatic activities decreased significantly with increase of concentrations of heavy metals or the distance away from mining tailing center, especially dehydrogenase and urease activities. Multivariate regression analysis between heavy metal contents and soil enzymatic activities indicated that single dehydrogenase activity was very significantly correlated to combined effect of soil heavy metals in mine area. Moreover, single urease, protease and acid phosphatase activities were significantly related to the combined effect of heavy metals. The results suggest it is feasible to use soil enzymatic activities to indicate the pollution situation by combined heavy metals in the soil of mine area.
基金Under the auspices of National Key Research and Development Program of China(No.2016YFD0800304)Natural Science Foundation of Shandong(No.ZR2017MD023,ZR2018BD003)
文摘The intensive management practices in greenhouse production may alter the soil physicochemical properties and contribute to the accumulation of heavy metals(HMs). To determine the HM concentrations in vegetable soil in relation to soil physicochemical properties and cultivation age, we conducted a soil survey for typical greenhouse soils in Shouguang, China. The results indicated that Cd is a major HM pollutant in the tested soils, as the only HM element exceeding the allowed limit for vegetable soil. The surveyed data was analyzed with regression analysis, correlation analysis and canonical correspondence analysis(CCA). A positive correlation is observed between HM pollution level and cultivation age. CCA results suggest that the HM pollution level and distribution in soil are significantly affected by soil physicochemical properties, which was a function of years of cultivation as revealed by regression analysis. In summary, cultivation age is an important factor to affect soil physicochemical properties(organic matter and inorganic nutrients) as well as HM contamination.
文摘The mechanism of interaction relation between the rare-earth element Ce and elements Pb and Bi in Ag-based filler metal has been studied. The results show that the compounds CePb and CeBi with high melting point can be easily produced between these three elements in the filler metal, which greatly limited the formation of the isolated phase Pb or Bi and also eliminated the bad effect of impurity elements Pb and Bi on the spreading property of Ag-based filler metal. The metallurgical and quantum-mechanical bond formation analysis show that a strong chemical affinity was existed between the rare-earth element Ce and impurity elements Pb and Bi, which was proved by the XRD analysis results.
基金supported by the Shenzhen Science and Technology innovation committee (Grant No. JCYJ.0180306172006392)。
文摘In this work,the sandwich joints were joined by low temperature pressureless sintering Ag paste.The morphology and thermal behavior of Ag nanoparticle paste was characterized and analyzed.The sintered Ag joints with different metallization were prepared and tested.The joints with Ag metallization exhibited superior shear strength and interface bonding ratio.However,the joints with Cu metallization showed lowest shear strength and interface delamination.The interfacial microstructures were observed and the diffusion kinetics between Ag and Au atoms were both calculated.The excessive diffusion of Ag atoms towards the Au layer deteriorated the interface bonding ratio and shear strength.This work will help understand the bonding mechanism between sintered Ag and other metallization.
基金funded by the Natural Science Foundation of China (grant No. 41702074)Sichuan Education Department Foundation (grant No. 17ZA0039)+2 种基金Young and Middle-Aged Teacher Foster Program of Chengdu University of Technology (grant No. JXGG201701)Opening Foundation of Key Laboratory of Tectonic Controls on Mineralization and Hydrocarbon Accumulation, Ministry of Land and Resources (grant No. gzck2018003)Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration in Guilin University of Technology (grant No. 12-071-20)
文摘Objective The Songpan-Garze Fold Belt(SGFB),located in the eastern part of the Tibet Plateau and west of the Sichuan Basin,is an important pegmatite province in China.Some famous pegmatite type deposits occur in the SGFB,including the Xuebaoding,Jiajika,Keeryin rare metal deposits and Danba muscovite deposit(Li Jiankang et al.,2015).The newly discovered super-large Lijiagou
基金This work was supported by the National Natural Science Foundation of China （Grant Nos. 41172110 and 61107090） and Shandong Provincial Natural Science Foundation （Grant No. ZR2011BZ007）.
