Eleven plant species were collected from the vicinity of lead-battery plant in the city of Gaziantep,Turkey.Lead,cadmium and copper concentrations in the soil and leaves of plants were determined by atomic absorption ...Eleven plant species were collected from the vicinity of lead-battery plant in the city of Gaziantep,Turkey.Lead,cadmium and copper concentrations in the soil and leaves of plants were determined by atomic absorption spectrometry.Lead,Cd and Cu concentrations in the soil samples taken from battery area were found to be in the ranges of 304～602,0.4～0.44 and 31～37 mg·kg-1,respectively.Significantly increased lead concentration up to 2 750 mg·kg-1 was found in the leaves of Eleagnus angustifolia L.plant.The lead concentrations in the other plant leaves taken from 50 m around battery factory followed the order Ailanthus altissima>Morus sp.>Juglans regia L.>Ficus carica L.>Cydonia oblonga Miller>Prunus x domestica L.The plants,Populus nigra L.,Eleagnus angustifolia L.and Salix sp.were found useful for Cd,and the plant,Eleagnus angustifolia L.for Pb,to be considered as potential biomonitor.Especially,leaves of trees and plants taken from the distance of 50 m from battery plant have relatively higher Pb concentrations.Therefore,people who and animals which live in this area and benefit from these soil and plants have vital risks.展开更多
CuS-graphene oxide/TiO2 composites were prepared using a sol-gel method to improve the photocatalytic performance of the photocatalyst. The composites were characterized by X-ray diffraction, scanning electron microsc...CuS-graphene oxide/TiO2 composites were prepared using a sol-gel method to improve the photocatalytic performance of the photocatalyst. The composites were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, and transmission electron microscopy. The photocatalytic activities were examined by the degradation of methylene blue (MB) under visible-light irradiation. The photodegradation of MB under visible-light irradiation reached 90.1% after 120 min. The kinetics of MB degradation was plotted alongside the values calculated from the Langmuir-Hinshelwood equation. The CuS-graphene oxide/TiO2 sample prepared using 0.2 mol of TiO2 showed the best photocatalytic activity. This was attributed to a cooperative reaction as a result of increased photoabsorption by graphene oxide and an increased photocatalytic effect by CuS.展开更多
This paper mainly presents the processing technique of various copper products and copper base alloys,including its melt and cast facilities as well as the production of plate,strip,tube,bar and wire,which prove that ...This paper mainly presents the processing technique of various copper products and copper base alloys,including its melt and cast facilities as well as the production of plate,strip,tube,bar and wire,which prove that the processing technique and facility in China have already been entered a new period and that the variety and quality have been raised to a new level.This paper also points out that China copper processing industry should further devote itself to the technical development,increase the variety,improve the quality,make good use of resources,develop processing products,and improve the management level.展开更多
Zambia＇s agricultural sector is gearing up to provide ample investment opportunities THINK of Zambia and what it produces and chances are.the first thought that comes to mind is the country＇s rich copper mining indu...Zambia＇s agricultural sector is gearing up to provide ample investment opportunities THINK of Zambia and what it produces and chances are.the first thought that comes to mind is the country＇s rich copper mining industry.However,in terms of contribution to GDP,the nation＇s agricultural sector is more important than its relatively mature mining sector and presents attractive investment opportunities.展开更多
Despite significant progress in catalytic asymmetric synthesis of chiral allenes via homogeneous or heterogeneous metal-catalyzed,photoexcited metal-catalyzed as well as certain exquisite organocatalytic asymmetric me...Despite significant progress in catalytic asymmetric synthesis of chiral allenes via homogeneous or heterogeneous metal-catalyzed,photoexcited metal-catalyzed as well as certain exquisite organocatalytic asymmetric methods,the asymmetric syntheses of chiral allenes via organo-phosphines catalysis are rare.In this paper,a catalytic asymmetric conjugate addition of malonic esters to yne-enones was successfully achieved via coperative catalysis of chiral biamide-phosphine and methyl acrylate,which afforded the corresponding chiral trisubstituted 1,2-allenyl ketones containing contigous axial and carbon center chirality with excellent enantioselectivity(up to 99%ee)and good diastereoselectivity(up to 93:7 dr).It is meaningful to note that the addition of an inorganic base(K_(2)CO_(3))did not cause the background racemic reaction but could enhance the reactivity as a co-catalyst.The developed protocol demonstrates a wide range of substrates,high tolerance to various functional groups,versatile product functionalization and ease of operation as well as mild reaction conditions.Additionally,this coperative catalytic mode will not only promote the design of novel chiral phosphine catalysts,but also shine some light on expanding the reaction scope of asymmetric phosphine catalysis.展开更多
Although significant advances have been accomplished in the synthesis ofα-chiral carboxylic acid derivatives through Wolff rearrangement ofα-diazo ketones via different asymmetric catalytic mode including transition...Although significant advances have been accomplished in the synthesis ofα-chiral carboxylic acid derivatives through Wolff rearrangement ofα-diazo ketones via different asymmetric catalytic mode including transition metal/photocatalysis,chiral Lewis base/photocatalysis,chiral SPA/photocatalysis and chiral NHC/photocatalysis,to the best of our knowledge,the construction of chiral carbon-heteroatom bond through Wolff rearrangement remains underdeveloped.In this paper,the first catalytic asymmetric thia-Wolff rearrangement betweenα-arylα-diazothioesters and amines has been successfully achieved under cooperative rhodium/chiral phosphoric acid catalysis,which provides efficient access to synthetically valuable chiralα-sulfenylated amide architectures.This protocol features mild reaction conditions,high efficiency,excellent stereoselectivity,a broad substrate scope,scalable synthesis and versatile product functionalization,highlighting its practical value in constructing various chiral sulfur-containing compounds.Additionally,this study significantly expand the utility of diazo compounds in Wolff rearrangement for asymmetric synthesis of sulfur-containing compounds and carbene transfer reactions.展开更多
文摘Eleven plant species were collected from the vicinity of lead-battery plant in the city of Gaziantep,Turkey.Lead,cadmium and copper concentrations in the soil and leaves of plants were determined by atomic absorption spectrometry.Lead,Cd and Cu concentrations in the soil samples taken from battery area were found to be in the ranges of 304～602,0.4～0.44 and 31～37 mg·kg-1,respectively.Significantly increased lead concentration up to 2 750 mg·kg-1 was found in the leaves of Eleagnus angustifolia L.plant.The lead concentrations in the other plant leaves taken from 50 m around battery factory followed the order Ailanthus altissima>Morus sp.>Juglans regia L.>Ficus carica L.>Cydonia oblonga Miller>Prunus x domestica L.The plants,Populus nigra L.,Eleagnus angustifolia L.and Salix sp.were found useful for Cd,and the plant,Eleagnus angustifolia L.for Pb,to be considered as potential biomonitor.Especially,leaves of trees and plants taken from the distance of 50 m from battery plant have relatively higher Pb concentrations.Therefore,people who and animals which live in this area and benefit from these soil and plants have vital risks.
基金supported by Research Foundation from Hanseo University in 2012
文摘CuS-graphene oxide/TiO2 composites were prepared using a sol-gel method to improve the photocatalytic performance of the photocatalyst. The composites were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, and transmission electron microscopy. The photocatalytic activities were examined by the degradation of methylene blue (MB) under visible-light irradiation. The photodegradation of MB under visible-light irradiation reached 90.1% after 120 min. The kinetics of MB degradation was plotted alongside the values calculated from the Langmuir-Hinshelwood equation. The CuS-graphene oxide/TiO2 sample prepared using 0.2 mol of TiO2 showed the best photocatalytic activity. This was attributed to a cooperative reaction as a result of increased photoabsorption by graphene oxide and an increased photocatalytic effect by CuS.
文摘This paper mainly presents the processing technique of various copper products and copper base alloys,including its melt and cast facilities as well as the production of plate,strip,tube,bar and wire,which prove that the processing technique and facility in China have already been entered a new period and that the variety and quality have been raised to a new level.This paper also points out that China copper processing industry should further devote itself to the technical development,increase the variety,improve the quality,make good use of resources,develop processing products,and improve the management level.
文摘Zambia＇s agricultural sector is gearing up to provide ample investment opportunities THINK of Zambia and what it produces and chances are.the first thought that comes to mind is the country＇s rich copper mining industry.However,in terms of contribution to GDP,the nation＇s agricultural sector is more important than its relatively mature mining sector and presents attractive investment opportunities.
基金support of the National Natural Science Foundation of China(22171088,22371074).
文摘Despite significant progress in catalytic asymmetric synthesis of chiral allenes via homogeneous or heterogeneous metal-catalyzed,photoexcited metal-catalyzed as well as certain exquisite organocatalytic asymmetric methods,the asymmetric syntheses of chiral allenes via organo-phosphines catalysis are rare.In this paper,a catalytic asymmetric conjugate addition of malonic esters to yne-enones was successfully achieved via coperative catalysis of chiral biamide-phosphine and methyl acrylate,which afforded the corresponding chiral trisubstituted 1,2-allenyl ketones containing contigous axial and carbon center chirality with excellent enantioselectivity(up to 99%ee)and good diastereoselectivity(up to 93:7 dr).It is meaningful to note that the addition of an inorganic base(K_(2)CO_(3))did not cause the background racemic reaction but could enhance the reactivity as a co-catalyst.The developed protocol demonstrates a wide range of substrates,high tolerance to various functional groups,versatile product functionalization and ease of operation as well as mild reaction conditions.Additionally,this coperative catalytic mode will not only promote the design of novel chiral phosphine catalysts,but also shine some light on expanding the reaction scope of asymmetric phosphine catalysis.
基金support of the National Natural Science Foundation of China(22171088,22371074).
文摘Although significant advances have been accomplished in the synthesis ofα-chiral carboxylic acid derivatives through Wolff rearrangement ofα-diazo ketones via different asymmetric catalytic mode including transition metal/photocatalysis,chiral Lewis base/photocatalysis,chiral SPA/photocatalysis and chiral NHC/photocatalysis,to the best of our knowledge,the construction of chiral carbon-heteroatom bond through Wolff rearrangement remains underdeveloped.In this paper,the first catalytic asymmetric thia-Wolff rearrangement betweenα-arylα-diazothioesters and amines has been successfully achieved under cooperative rhodium/chiral phosphoric acid catalysis,which provides efficient access to synthetically valuable chiralα-sulfenylated amide architectures.This protocol features mild reaction conditions,high efficiency,excellent stereoselectivity,a broad substrate scope,scalable synthesis and versatile product functionalization,highlighting its practical value in constructing various chiral sulfur-containing compounds.Additionally,this study significantly expand the utility of diazo compounds in Wolff rearrangement for asymmetric synthesis of sulfur-containing compounds and carbene transfer reactions.
