Rechargeable lithium-oxygen(Li-O_(2))batteries have attracted wide attention due to their high energy density.However,the sluggish cathode kinetics results in high overvoltage and poor cycling performance.Ruthenium(Ru...Rechargeable lithium-oxygen(Li-O_(2))batteries have attracted wide attention due to their high energy density.However,the sluggish cathode kinetics results in high overvoltage and poor cycling performance.Ruthenium(Ru)-based electrocatalysts have been demonstrated to be promising cathode catalysts to promote oxygen evolution reaction(OER).It facilitates decomposition of lithium peroxide(Li_(2)O_(2))by adjusting Li_(2)O_(2) morphologies,which is due to the strong interaction between Ru-based catalyst and superoxide anion(O_(2))intermediate.In this review,the design strategies of Ru-based electrocatalysts are introduced to enhance their OER catalytic kinetics in Li-O_(2) batteries.Different configurations of Ru-based catalysts,including metal particles(Ru metal and alloys),single-atom catalysts,and Ru-loaded compounds with various substrates(carbon materials,metal oxides/sulfides),have been summarized to regulate the electronic structure and the matrix architecture of the Ru-based electrocatalysts.The structure-property relationship of Ru-based catalysts is discussed for a better understanding of the Li_(2)O_(2) decomposition mechanism at the cathode interface.Finally,the challenges of Ru-based electrocatalysts are proposed for the future development of Li-O_(2) batteries.展开更多
TiN-matrix composite coating was prepared on 45# steel by reactive high-velocity oxy-fuel （HVOF） spraying. Its microstructure, phase composition, micro-hardness, corrosion resistance in 3.5% NaC1 solution and wear r...TiN-matrix composite coating was prepared on 45# steel by reactive high-velocity oxy-fuel （HVOF） spraying. Its microstructure, phase composition, micro-hardness, corrosion resistance in 3.5% NaC1 solution and wear resistance were analyzed. The results suggest that the TiN-matrix composite coating is well bonded with the substrate. The micro-hardness measured decreases with the increase of applied test loads. And the micro-hardness of the coating under heavy loads is relatively high. The TiN-matrix composite coating exhibits an excellent corrosion resistance in 3.5% NaC1 solution. The corrosion potential of coating is positive and the passivation zone is broad, which indicates that the TiN-matrix composite coating is stable in the electrolyte and provides excellent protection to the substrate. The wear coefficient of the coating under all loads maintains at 0.49-0.50. The wear mechanism of the coating is revealed to be three-body abrasive wear. Yet the failure forms of TiN-matrix composite coating under different loads have an obvious difference. The failure form of coating under light loads is particle spallation due to the stress concentration while that of coating under heavy loads is crackin~ between inter-lamellae.展开更多
[Objective] This study was to find out a quick,simple,and low-cost method for the extraction of sorghum genomic DNA.[Method] Four plant genomic DNA extraction methods based on CTAB,including liquid nitrogen grinding m...[Objective] This study was to find out a quick,simple,and low-cost method for the extraction of sorghum genomic DNA.[Method] Four plant genomic DNA extraction methods based on CTAB,including liquid nitrogen grinding method（method I）,buffer grinding method（method II）,drying grinding method（method III）and directly grinding method（method IV）,were used to extract the sorghum genomic DNA from leaves;further the quantity and quality of the yielded DNA were detected by gel electrophoresis,SSR-PCR and SRAP-PCR.[Result] These four methods performed no remarkable difference in DNA product.The method I and method II produced DNA with higher purity and better integrity,which,especially from method I,is effective for SRAP-PCR and SSR-PCR.While the DNA extracted via method III and method IV had less integrality and lower purity,and only effective in SSR-PCR.[Conclusion] Enough amount of sorghum genomic DNA to perform tens of PCR could be quickly extracted using all these four methods.The DNA obtained via method I and method II had a broader application spectrum（SRAP,RAPD,ISSR and SSR）than that via method III and method IV which is only proper for PCR targeting small DNA fragments（SSR）.展开更多
基金the National Natural Science Foundation of China(22325902 and 51671107)Haihe Laboratory of Sustainable Chemical Transformations.
文摘Rechargeable lithium-oxygen(Li-O_(2))batteries have attracted wide attention due to their high energy density.However,the sluggish cathode kinetics results in high overvoltage and poor cycling performance.Ruthenium(Ru)-based electrocatalysts have been demonstrated to be promising cathode catalysts to promote oxygen evolution reaction(OER).It facilitates decomposition of lithium peroxide(Li_(2)O_(2))by adjusting Li_(2)O_(2) morphologies,which is due to the strong interaction between Ru-based catalyst and superoxide anion(O_(2))intermediate.In this review,the design strategies of Ru-based electrocatalysts are introduced to enhance their OER catalytic kinetics in Li-O_(2) batteries.Different configurations of Ru-based catalysts,including metal particles(Ru metal and alloys),single-atom catalysts,and Ru-loaded compounds with various substrates(carbon materials,metal oxides/sulfides),have been summarized to regulate the electronic structure and the matrix architecture of the Ru-based electrocatalysts.The structure-property relationship of Ru-based catalysts is discussed for a better understanding of the Li_(2)O_(2) decomposition mechanism at the cathode interface.Finally,the challenges of Ru-based electrocatalysts are proposed for the future development of Li-O_(2) batteries.
基金Project(KFJJ10-15M) supported by the Open Fund of State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology,ChinaProject(E2013208101) supported by the Nature Science Fund of Hebei Province,China+1 种基金Project(Z2012100) supported by Colleges and Universities Science and Technology Research Fund of Hebei Province,ChinaProject supported by the Outstanding Youth Fund of Hebei University of Science and Technology,China
文摘TiN-matrix composite coating was prepared on 45# steel by reactive high-velocity oxy-fuel （HVOF） spraying. Its microstructure, phase composition, micro-hardness, corrosion resistance in 3.5% NaC1 solution and wear resistance were analyzed. The results suggest that the TiN-matrix composite coating is well bonded with the substrate. The micro-hardness measured decreases with the increase of applied test loads. And the micro-hardness of the coating under heavy loads is relatively high. The TiN-matrix composite coating exhibits an excellent corrosion resistance in 3.5% NaC1 solution. The corrosion potential of coating is positive and the passivation zone is broad, which indicates that the TiN-matrix composite coating is stable in the electrolyte and provides excellent protection to the substrate. The wear coefficient of the coating under all loads maintains at 0.49-0.50. The wear mechanism of the coating is revealed to be three-body abrasive wear. Yet the failure forms of TiN-matrix composite coating under different loads have an obvious difference. The failure form of coating under light loads is particle spallation due to the stress concentration while that of coating under heavy loads is crackin~ between inter-lamellae.
基金Supported by Key Technology R&D Program of Tianjin(10ZCKFNC00100)National Key Technology R&D Program(2007BAD42B03)~~
文摘[Objective] This study was to find out a quick,simple,and low-cost method for the extraction of sorghum genomic DNA.[Method] Four plant genomic DNA extraction methods based on CTAB,including liquid nitrogen grinding method（method I）,buffer grinding method（method II）,drying grinding method（method III）and directly grinding method（method IV）,were used to extract the sorghum genomic DNA from leaves;further the quantity and quality of the yielded DNA were detected by gel electrophoresis,SSR-PCR and SRAP-PCR.[Result] These four methods performed no remarkable difference in DNA product.The method I and method II produced DNA with higher purity and better integrity,which,especially from method I,is effective for SRAP-PCR and SSR-PCR.While the DNA extracted via method III and method IV had less integrality and lower purity,and only effective in SSR-PCR.[Conclusion] Enough amount of sorghum genomic DNA to perform tens of PCR could be quickly extracted using all these four methods.The DNA obtained via method I and method II had a broader application spectrum（SRAP,RAPD,ISSR and SSR）than that via method III and method IV which is only proper for PCR targeting small DNA fragments（SSR）.
