Direct electrodeposition of quarternary Mg-Zn-Li-Ca alloys on a molybdenum electrode from LiCl-KCl-MgCl2-ZnCl2-CaCl2 melts at 943 K was investigated.Cyclic voltammograms（CVs） show that the deposition potential of Li...Direct electrodeposition of quarternary Mg-Zn-Li-Ca alloys on a molybdenum electrode from LiCl-KCl-MgCl2-ZnCl2-CaCl2 melts at 943 K was investigated.Cyclic voltammograms（CVs） show that the deposition potential of Li shifts in a positive direction after adding MgCl2,ZnCl2 and CaCl2.Chronopotentiometric measurements indicate that the codepositon of Mg,Li,Zn,and Ca occurs at current densities lower than-1.55 A/cm2.X-ray diffraction（XRD） indicates that Mg-Zn-Li-Ca alloys with different phases were prepared via galvanostatic electrolysis.The microstructures of typical phase of Mg-Zn-Li-Ca alloys were characterized by optical microscopy（OM） and scanning electron microscopy（SEM）.The analysis of energy dispersive spectrometry（EDS） shows that elements of Mg and Ca distribute homogeneously in the Mg-Zn-Li-Ca alloy.However,element Zn mainly locates at the edges of the domain.展开更多
Three pillar-layered metal-organic frameworks（MOFs） based on M（HBTC）（4,4＇-bipy）.3DMF（M =Ni, Co, and Zn; HBTC = 1,3,5-benzenetricarboxylic acid, 4,4＇-bipy = 4,4′-bipyridine） were synthesized using a solvothe...Three pillar-layered metal-organic frameworks（MOFs） based on M（HBTC）（4,4＇-bipy）.3DMF（M =Ni, Co, and Zn; HBTC = 1,3,5-benzenetricarboxylic acid, 4,4＇-bipy = 4,4′-bipyridine） were synthesized using a solvothermal method. Zn（HBTC）（4,4＇-bipy）.3DMF was synthesized for the first time using both a solvothermal and microwave method, and subsequently characterized by various physicochemical methods. The structure of M（HBTC）（4,4＇-bipy）.3DMF consisted of honeycomb grid layers of M2＋ ions and BTC units, which were further linked by the 4,4＇-bipy pillars to form a three-dimensional highly porous framework. All the MOFs displayed excellent synergistic catalytic properties with alkyl ammonium halides（TBAX） in the solventless fixation of CO_2 with epoxides to produce cyclic carbonates. The catalytic activities of these MOFs followed the trend Zn Co Ni,which was explained by the acid-base bifunctional properties. The microwave-synthesized Zn（HBTC）（4,4＇-bipy）.3DMF material exhibited physical, chemical, and catalytic properties that were similar to those of the catalyst obtained using a conventional solvothermal synthesis. The scope of various parameters, including recyclability, was studied, and a plausible reaction mechanism was suggested.展开更多
A straightforward and efficient protocol for dearomatizing indoles is described.The reaction,catalyzed by an inexpensive Co(III)/Zn(II)catalyst,starts from easily accessible N‐pyrimidinyl indoles and ene‐yne ketones...A straightforward and efficient protocol for dearomatizing indoles is described.The reaction,catalyzed by an inexpensive Co(III)/Zn(II)catalyst,starts from easily accessible N‐pyrimidinyl indoles and ene‐yne ketones.Mild reaction conditions,high diastereoselectivity,a broad substrate scope,effective functional group tolerance,and reasonable to remarkable yields were observed.展开更多
Elements （vanadium and zinc） were determined in the two most abundant species of shell mollusks （Unio tigridis and Fiviparous bengalensis） and the water where they live in five stations in the Iraqi marshes. The s...Elements （vanadium and zinc） were determined in the two most abundant species of shell mollusks （Unio tigridis and Fiviparous bengalensis） and the water where they live in five stations in the Iraqi marshes. The study of concentrations elements was a target organ for aquatic environmental. Comparison between the mean concentrations of the elements in the water concentration levels of all studied elements was the highest with the mollusks. The results show that the station 5 is where the highest concentrations are found in water and in the two species. There is a significant correlation （P = 0.224） for concentrations of vanadium and P = 0.735 for zinc in two species of mollusks relative to their concentrations in surface water. All significant differences were accepted at a level of P 〈 0.05. The potential uptake of elements including V and Zn, as Viviparous bengalensi 〉 Unio tigridis, The mechanism for elements uptake determined by water for organisms confined to the contaminated areas seemed to be largely independent of species, mollusks demonstrated a significant positive relationship with water. These results have important implications for the utility of marshes biota as subjects for elements monitoring program.展开更多
基金Project(2011AA03A409) supported by the High-tech Research and Development Program of ChinaProjects(21103033,21101040, 21173060,91226201) supported by the National Natural Science Foundation of China+1 种基金Project(HEUCF20130012) supported by the Fundamental Research Funds for the Central Universities,ChinaProject(1253G016) supported by the Foundation for University Key Teacher of Heilongjiang Province of China
文摘Direct electrodeposition of quarternary Mg-Zn-Li-Ca alloys on a molybdenum electrode from LiCl-KCl-MgCl2-ZnCl2-CaCl2 melts at 943 K was investigated.Cyclic voltammograms（CVs） show that the deposition potential of Li shifts in a positive direction after adding MgCl2,ZnCl2 and CaCl2.Chronopotentiometric measurements indicate that the codepositon of Mg,Li,Zn,and Ca occurs at current densities lower than-1.55 A/cm2.X-ray diffraction（XRD） indicates that Mg-Zn-Li-Ca alloys with different phases were prepared via galvanostatic electrolysis.The microstructures of typical phase of Mg-Zn-Li-Ca alloys were characterized by optical microscopy（OM） and scanning electron microscopy（SEM）.The analysis of energy dispersive spectrometry（EDS） shows that elements of Mg and Ca distribute homogeneously in the Mg-Zn-Li-Ca alloy.However,element Zn mainly locates at the edges of the domain.
文摘Three pillar-layered metal-organic frameworks（MOFs） based on M（HBTC）（4,4＇-bipy）.3DMF（M =Ni, Co, and Zn; HBTC = 1,3,5-benzenetricarboxylic acid, 4,4＇-bipy = 4,4′-bipyridine） were synthesized using a solvothermal method. Zn（HBTC）（4,4＇-bipy）.3DMF was synthesized for the first time using both a solvothermal and microwave method, and subsequently characterized by various physicochemical methods. The structure of M（HBTC）（4,4＇-bipy）.3DMF consisted of honeycomb grid layers of M2＋ ions and BTC units, which were further linked by the 4,4＇-bipy pillars to form a three-dimensional highly porous framework. All the MOFs displayed excellent synergistic catalytic properties with alkyl ammonium halides（TBAX） in the solventless fixation of CO_2 with epoxides to produce cyclic carbonates. The catalytic activities of these MOFs followed the trend Zn Co Ni,which was explained by the acid-base bifunctional properties. The microwave-synthesized Zn（HBTC）（4,4＇-bipy）.3DMF material exhibited physical, chemical, and catalytic properties that were similar to those of the catalyst obtained using a conventional solvothermal synthesis. The scope of various parameters, including recyclability, was studied, and a plausible reaction mechanism was suggested.
文摘A straightforward and efficient protocol for dearomatizing indoles is described.The reaction,catalyzed by an inexpensive Co(III)/Zn(II)catalyst,starts from easily accessible N‐pyrimidinyl indoles and ene‐yne ketones.Mild reaction conditions,high diastereoselectivity,a broad substrate scope,effective functional group tolerance,and reasonable to remarkable yields were observed.
文摘Elements （vanadium and zinc） were determined in the two most abundant species of shell mollusks （Unio tigridis and Fiviparous bengalensis） and the water where they live in five stations in the Iraqi marshes. The study of concentrations elements was a target organ for aquatic environmental. Comparison between the mean concentrations of the elements in the water concentration levels of all studied elements was the highest with the mollusks. The results show that the station 5 is where the highest concentrations are found in water and in the two species. There is a significant correlation （P = 0.224） for concentrations of vanadium and P = 0.735 for zinc in two species of mollusks relative to their concentrations in surface water. All significant differences were accepted at a level of P 〈 0.05. The potential uptake of elements including V and Zn, as Viviparous bengalensi 〉 Unio tigridis, The mechanism for elements uptake determined by water for organisms confined to the contaminated areas seemed to be largely independent of species, mollusks demonstrated a significant positive relationship with water. These results have important implications for the utility of marshes biota as subjects for elements monitoring program.
