It is necessary to adopt a specific strategy to construct an efficient and low-cost transition metal-based composite to replace the precious metal-based electrocatalyst for OER catalytic processes.In this work,a beade...It is necessary to adopt a specific strategy to construct an efficient and low-cost transition metal-based composite to replace the precious metal-based electrocatalyst for OER catalytic processes.In this work,a beaded stream-like N and P-codoped carbon-coated Fe_(3)O_(4)nanocomposite(N,P-Fe_(3)O_(4)@C)is derived from MIL-88A by two-step annealing.The unique 3D nanostructure and amorphous N-doped carbon layer enlarge the number of active sites,and P doping changes the pathway from AEM to LOM.The synergistic effect of these factors results in N,P-Fe_(3)O_(4)@C presenting excellent OER catalytic activity with an overpotential of 201 mV(η10),a Tafel slope of 57.1 mV/dec and stable operation for 100 h(the current density is 10 mA/cm^(2)).Density functional theory calculations and electrochemical tests reveal that the P doping enhances the overlap of Fe 3d orbital bands and O 2p orbitals,and thus significantly increases the metaloxygen covalency,triggering the pathway transition from AEM to LOM.This work provides a new way to construct more efficient transition metal-based composite carbon materials.展开更多
Impacts of salinity become severe when the soil is deficient in oxygen. OxygaUon （using aerated water for subsurface drip irrigation of crop） could minimize the impact of salinity on plants under oxygen-limiting soi...Impacts of salinity become severe when the soil is deficient in oxygen. OxygaUon （using aerated water for subsurface drip irrigation of crop） could minimize the impact of salinity on plants under oxygen-limiting soil environments. Pot experiments were conducted to evaluate the effects of oxygation （12% air volume/volume of water） on vegetable soybean （moderately salt tolerant） and cotton （salt tolerant） in a salinized vertisol at 2, 8, 14, 20 dS/m ECe. In vegetable soybean, oxygation increased above ground biomass yield and water use efficiency （WUE） by 13% and 22%, respectively, compared with the control. Higher yield with oxygation was accompanied by greater plant height and stem diameter and reduced specific leaf area and leaf Na^＋ and CI^- concentrations. In cotton, oxygation increased lint yield and WUE by 18% and 16%, respectively, compared with the control, and was accompanied by greater canopy light interception, plant height and stem diameter. Oxygation also led to a greater rate of photosynthesis, higher relative water content in the leaf, reduced crop water stress index and lower leaf water potential. It did not, however, affect leaf Na^＋ or CI^- concentration. Oxygation invariably increased, whereas salinity reduced the K^＋： Na^＋ ratio in the leaves of both species. Oxygation improved yield and WUE performance of salt tolerant and moderately tolerant crops under saline soil environments, and this may have a significant impact for irrigated agriculture where saline soils pose constraints to crop production.展开更多
Oxygation refers to irrigation of crops with aerated water,through air injection using the venturi principle or the supply of hydrogen peroxide in the root zone,both using subsurface drip irrigation(SDI)system.Oxygati...Oxygation refers to irrigation of crops with aerated water,through air injection using the venturi principle or the supply of hydrogen peroxide in the root zone,both using subsurface drip irrigation(SDI)system.Oxygation improves water use efficiency(WUE),producing more yield and,and therefore,optimizes the use of drip and SDI.But the efficiency of oxygation is quite possibly dependent on a number of factors.The primary objective of this study was,therefore,to quantify the effects of oxygation,emitter depths and soil type on crop root zone oxygen content,soil respiration,plant physiological response,biomass yield,quality and WUE of three crop species.Methods This study investigated the potential of oxygation to enhance soil respiration,plant growth,yield and water use efficiencies(WUE)of cotton and wheat in experiments in enclosed heavy-duty concrete troughs(tubs)and pineapple and cotton in field experiments.Experimental treatments in tubs for wheat included comparisons between two soil types(vertisol and ferrosol)and superimposed were two oxygation methods(Mazzei air injector and Seair Diffusion System)compared to a control,and for cotton,emitters at two depths using Mazzei air injectors were compared to a control.The field experiments compared Mazzei air injectors and a control for cotton in Emerald and pineapple in Yeppoon,both in central Queensland,Australia.Important findings In all experiments,soil oxygen content and soil respiration markedly increased in response to the oxygation treatments.The O2 concentration in the crop root zone increased by 2.4–32.6%,for oxygation compared to control at the same depth.The soil respiration increased by 42–100%.The number of wheat ears,leaf dry weight and total dry matter were significantly greater in Mazzei and Seair oxygation compared to the control.Fresh biomass of wheat increased by 11 and 8%,and dry weight of wheat increased by 8 and 3%in Mazzei and Seair oxygation treatments compared to the control,respectively.Likewise,the irrigation water use efficiency increased with oxygation compared to the control in wheat.The yield,WUE and number of other physiological parameters in wheat were enhanced in vertisol compared to ferrosol.The seed cotton yield in the tub experiment increased with oxygation by 14%,and significant differences for fresh biomass,dry matter and yield were also noted between oxygation and the control in the field.Lint yield and WUE both increased by 7%using Mazzei in the cotton field trial during 2008–09.There were significant effects of oxygation on pineapple fresh biomass,and dry matter weight,industry yield and a number of quality parameters were significantly improved.The total fruit yield and marketable increased by 17 and 4%and marketable WUE increased by 3%using Mazzei.Our data suggest that the benefits of oxygation are notable not only for dicotyledonous cotton but also for monocotyledonous wheat and pineapple representing different rooting morphologies and CO_(2) fixation pathways.展开更多
目的探讨4 d头低位卧床(head-down bed rest,HDBR)模拟失重对人体运动能力的影响及人工重力联合中等强度运动锻炼的对抗效果。方法 12名健康男性志愿者随机分为2组:对照组(n=6)仅进行4 d HDBR;对抗组(n=6)HDBR期间每天上下午各进行1次30...目的探讨4 d头低位卧床(head-down bed rest,HDBR)模拟失重对人体运动能力的影响及人工重力联合中等强度运动锻炼的对抗效果。方法 12名健康男性志愿者随机分为2组:对照组(n=6)仅进行4 d HDBR;对抗组(n=6)HDBR期间每天上下午各进行1次30 min基于人工重力(足水平2 Gz)的中等强度运动锻炼。HDBR前后对所有志愿者分别进行有氧和无氧运动能力测试。结果 HDBR后对照组递增负荷累计运动应激指数、最大摄氧量、无氧阈及30 s最大负荷运动中的最小无氧功较卧床前均显著下降(P<0.05),无氧功递减率显著升高(P<0.05)而无氧功峰值、平均无氧功均无显著改变;HDBR后对抗组上述各项指标均无显著改变。结论 4 d HDBR可致人体运动能力下降,其中对有氧运动能力影响最大,对无氧运动能力影响较小。基于人工重力的中等强度运动锻炼可有效对抗模拟失重所致的有氧及无氧运动耐力下降。展开更多
基金the National Nature Science Foundation of China(No.22304021)National Key Research and Development Project(No.2022YFA1505300)Sichuan Department of Science and Technology Program of China(No.2022YFG0312)for financial support。
文摘It is necessary to adopt a specific strategy to construct an efficient and low-cost transition metal-based composite to replace the precious metal-based electrocatalyst for OER catalytic processes.In this work,a beaded stream-like N and P-codoped carbon-coated Fe_(3)O_(4)nanocomposite(N,P-Fe_(3)O_(4)@C)is derived from MIL-88A by two-step annealing.The unique 3D nanostructure and amorphous N-doped carbon layer enlarge the number of active sites,and P doping changes the pathway from AEM to LOM.The synergistic effect of these factors results in N,P-Fe_(3)O_(4)@C presenting excellent OER catalytic activity with an overpotential of 201 mV(η10),a Tafel slope of 57.1 mV/dec and stable operation for 100 h(the current density is 10 mA/cm^(2)).Density functional theory calculations and electrochemical tests reveal that the P doping enhances the overlap of Fe 3d orbital bands and O 2p orbitals,and thus significantly increases the metaloxygen covalency,triggering the pathway transition from AEM to LOM.This work provides a new way to construct more efficient transition metal-based composite carbon materials.
基金funded by Central Queensland University Rockhampton,Australia
文摘Impacts of salinity become severe when the soil is deficient in oxygen. OxygaUon （using aerated water for subsurface drip irrigation of crop） could minimize the impact of salinity on plants under oxygen-limiting soil environments. Pot experiments were conducted to evaluate the effects of oxygation （12% air volume/volume of water） on vegetable soybean （moderately salt tolerant） and cotton （salt tolerant） in a salinized vertisol at 2, 8, 14, 20 dS/m ECe. In vegetable soybean, oxygation increased above ground biomass yield and water use efficiency （WUE） by 13% and 22%, respectively, compared with the control. Higher yield with oxygation was accompanied by greater plant height and stem diameter and reduced specific leaf area and leaf Na^＋ and CI^- concentrations. In cotton, oxygation increased lint yield and WUE by 18% and 16%, respectively, compared with the control, and was accompanied by greater canopy light interception, plant height and stem diameter. Oxygation also led to a greater rate of photosynthesis, higher relative water content in the leaf, reduced crop water stress index and lower leaf water potential. It did not, however, affect leaf Na^＋ or CI^- concentration. Oxygation invariably increased, whereas salinity reduced the K^＋： Na^＋ ratio in the leaves of both species. Oxygation improved yield and WUE performance of salt tolerant and moderately tolerant crops under saline soil environments, and this may have a significant impact for irrigated agriculture where saline soils pose constraints to crop production.
基金Horticulture Australia LimitedNational Program for Sustainable Irrigation,AustraliaNational Natural Science Foundation of China(no.50779059).
文摘Oxygation refers to irrigation of crops with aerated water,through air injection using the venturi principle or the supply of hydrogen peroxide in the root zone,both using subsurface drip irrigation(SDI)system.Oxygation improves water use efficiency(WUE),producing more yield and,and therefore,optimizes the use of drip and SDI.But the efficiency of oxygation is quite possibly dependent on a number of factors.The primary objective of this study was,therefore,to quantify the effects of oxygation,emitter depths and soil type on crop root zone oxygen content,soil respiration,plant physiological response,biomass yield,quality and WUE of three crop species.Methods This study investigated the potential of oxygation to enhance soil respiration,plant growth,yield and water use efficiencies(WUE)of cotton and wheat in experiments in enclosed heavy-duty concrete troughs(tubs)and pineapple and cotton in field experiments.Experimental treatments in tubs for wheat included comparisons between two soil types(vertisol and ferrosol)and superimposed were two oxygation methods(Mazzei air injector and Seair Diffusion System)compared to a control,and for cotton,emitters at two depths using Mazzei air injectors were compared to a control.The field experiments compared Mazzei air injectors and a control for cotton in Emerald and pineapple in Yeppoon,both in central Queensland,Australia.Important findings In all experiments,soil oxygen content and soil respiration markedly increased in response to the oxygation treatments.The O2 concentration in the crop root zone increased by 2.4–32.6%,for oxygation compared to control at the same depth.The soil respiration increased by 42–100%.The number of wheat ears,leaf dry weight and total dry matter were significantly greater in Mazzei and Seair oxygation compared to the control.Fresh biomass of wheat increased by 11 and 8%,and dry weight of wheat increased by 8 and 3%in Mazzei and Seair oxygation treatments compared to the control,respectively.Likewise,the irrigation water use efficiency increased with oxygation compared to the control in wheat.The yield,WUE and number of other physiological parameters in wheat were enhanced in vertisol compared to ferrosol.The seed cotton yield in the tub experiment increased with oxygation by 14%,and significant differences for fresh biomass,dry matter and yield were also noted between oxygation and the control in the field.Lint yield and WUE both increased by 7%using Mazzei in the cotton field trial during 2008–09.There were significant effects of oxygation on pineapple fresh biomass,and dry matter weight,industry yield and a number of quality parameters were significantly improved.The total fruit yield and marketable increased by 17 and 4%and marketable WUE increased by 3%using Mazzei.Our data suggest that the benefits of oxygation are notable not only for dicotyledonous cotton but also for monocotyledonous wheat and pineapple representing different rooting morphologies and CO_(2) fixation pathways.
文摘目的探讨4 d头低位卧床(head-down bed rest,HDBR)模拟失重对人体运动能力的影响及人工重力联合中等强度运动锻炼的对抗效果。方法 12名健康男性志愿者随机分为2组:对照组(n=6)仅进行4 d HDBR;对抗组(n=6)HDBR期间每天上下午各进行1次30 min基于人工重力(足水平2 Gz)的中等强度运动锻炼。HDBR前后对所有志愿者分别进行有氧和无氧运动能力测试。结果 HDBR后对照组递增负荷累计运动应激指数、最大摄氧量、无氧阈及30 s最大负荷运动中的最小无氧功较卧床前均显著下降(P<0.05),无氧功递减率显著升高(P<0.05)而无氧功峰值、平均无氧功均无显著改变;HDBR后对抗组上述各项指标均无显著改变。结论 4 d HDBR可致人体运动能力下降,其中对有氧运动能力影响最大,对无氧运动能力影响较小。基于人工重力的中等强度运动锻炼可有效对抗模拟失重所致的有氧及无氧运动耐力下降。
