Palladium-based catalysts have long been considered the benchmark for methane combustion;however,the authentic phase of catalytic active sites remains a subject of ongoing debate.Additionally,challenges like water-poi...Palladium-based catalysts have long been considered the benchmark for methane combustion;however,the authentic phase of catalytic active sites remains a subject of ongoing debate.Additionally,challenges like water-poisoning and long-term stability need to be addressed to advance catalyst performance.Herein,we investigate Pd on Co_(3)O_(4) nanorods as a highly effective catalyst for catalytic oxidation of methane,demonstrating long-term stability and water tolerance during a 100-h continuous operation at 350℃.Comprehensive characterizations reveal the presence of an active Pd-oxygen vacancy(Ov)-cobalt interface in Pd/Co_(3)O_(4),which effectively adsorbs molecular O_(2).The absorbed oxygen species on this interface are activated and directly participate in methane combustion.Moreover,near-ambient pressure X-ray photoelectron spectroscopy demonstrates that Pd nanoparticles undergo a rapid phase transition and predominantly remain in the metallic state during the reaction.This behavior is attributed to the electronic metal-support interaction between Pd and Co_(3)O_(4).Furthermore,in situ Fourier transformed infrared spectrum reveals that under reaction conditions,HCO3*species are formed initially and subsequently transformed into formate species,indicating that the formate pathway is the dominant mechanism for CH_(4) oxidation.展开更多
In recent years,persistent luminescence materials(PLMs)excited by X-rays and emitting in biological windows have received extensive attention in the field of high-sensitivity bioimaging.Transition metal Mn^(2+)is an i...In recent years,persistent luminescence materials(PLMs)excited by X-rays and emitting in biological windows have received extensive attention in the field of high-sensitivity bioimaging.Transition metal Mn^(2+)is an ideal emission center,but few studies focus on Mn^(2+)-doped PLMs with X-ray excitation and biological window emission.Here,we report a Mn^(2+)-doped PLM,LiYGeO_(4):Mn^(2+)(LYGM),with excellent biological window persistent luminescence emission.After excitation by UV,LYGM produces a durable biological window of persistent luminescence emission at 660 nm for up to 20 h.More importantly.LYGM can be repeatedly excited by X-rays,resulting in long-term biological window persistent luminescence emission.In addition,we obtain LYGM around 200 nm in diameter by ball milling and centrifugation and improve its biocompatibility by surface modification to apply it to in vivo imaging in mice.After LYGM are injected into mice through the tail vein,in situ excitation of X-rays can be achieved.After the persistent luminescence decays,LYGM can be re-excited for repeated imaging.Therefore,LYGM shows potential prospects for in vivo deep tissue and long-term bioimaging.展开更多
For many water quality studies,a data analyst,or modeler, may need to know the spatio-temproal patterns of the data sets and their relationships in both pre-processing and post-processing. Geographic Information Syste...For many water quality studies,a data analyst,or modeler, may need to know the spatio-temproal patterns of the data sets and their relationships in both pre-processing and post-processing. Geographic Information System(GIS) can provide an exploratory spat展开更多
Developing supercapacitors(SCs)with long cycling life and wide operative voltage window is a significant topic in the field of aqueous electrolytes.Although the design of water in salt(WIS)electrolytes has pushed the ...Developing supercapacitors(SCs)with long cycling life and wide operative voltage window is a significant topic in the field of aqueous electrolytes.Although the design of water in salt(WIS)electrolytes has pushed the development of aqueous electrolytes to a new height,the WIS electrolytes with an operative voltage window of up to 2.5 V is still very scarce.Herein,in order to enrich the type of aqueous electrolyte with high operative voltage,tetramethylammonium trifluoromethanesulfonate(TMAOTf)based WIS electrolyte was used as a model to construct WIS based hybrid electrolyte with acetonitrile(ACN)co-solvent and LiTFSI co-solute.In view of the coordination effect of ACN and Lit on free water in TMAOTf based WIS electrolyte,the TMAt-Lit-AWIS electrolyte has the electrochemical stabilization window of up to 3.35 V.Further coupled with the commercial YP-50F electrodes,TMAt-Lit-AWIS based SCs exhibited wide operative voltage window(2.5 V),long cycling life(45,000 cycles)and good low-temperature performance(99.99%capacitance retention after 2000 cycles at20℃).The design of this hybrid electrolyte will enrich the types of aqueous hybrid electrolytes with long cycling life and wide operative voltage window.展开更多
Promoting the development of deep-sea mineral exploration instrumentation can help alleviate the global resource shortage faced by mankind.X-ray fluorescence(XRF)spectrometry has been widely used in the in situ analys...Promoting the development of deep-sea mineral exploration instrumentation can help alleviate the global resource shortage faced by mankind.X-ray fluorescence(XRF)spectrometry has been widely used in the in situ analysis of deep-sea minerals owing to its fast analytical speed,nondestructive nature,and wide analytical range.This study focused on the structural safety and detection efficiency of X-ray fluorescence in situ measurement equipment under high pressure for deep-sea XRF analysis.This study first combined finite element analysis and experiments to design and optimize the structure of an X-ray probe tube required for deep-sea mineral exploration and to determine the Be window thickness to ensure stress safety.Subsequently,the Monte Carlo method was used to analyze and optimize the Be window thickness on the X-ray probe tube to improve the accuracy of the elemental analyses.Finally,the effect of seawater thickness between the transmitter outer tube and rock wall was also considered.The results show that based on ocean depth in different detection environments,Be windows with a thickness of 1.5 mm or 2.0 mm can be selected to improve the detection efficiency of the device while ensuring the structural safety of the instrument.According to the design features and detection requirements of the device,in deep-sea exploration of minerals with characteristic peak energies below 10 keV,the transmitter outer tube should be as close as possible to the rock wall inside the logging.When the characteristic peak energy of the minerals is more than 10 keV,the distance between the transmitter outer tube and rock wall inside the logging should be controlled to approximately 2 mm.This study provides feasible solutions for future deep-sea mineral resource development and a useful reference for elemental analysis of minerals in the deep-sea or other extreme working environments.展开更多
目的:探讨双能CT(DECT)重建图量化缺血脑组织净水摄取值(NWU)在评估急性缺血性卒中(AIS)患者组织窗的价值。方法:回顾性收集2016年12月至2022年5月期间接受DECT和CT灌注(CTP)的122例AIS患者资料,根据CTP将其分为获益组(n=83)及非获益组(...目的:探讨双能CT(DECT)重建图量化缺血脑组织净水摄取值(NWU)在评估急性缺血性卒中(AIS)患者组织窗的价值。方法:回顾性收集2016年12月至2022年5月期间接受DECT和CT灌注(CTP)的122例AIS患者资料,根据CTP将其分为获益组(n=83)及非获益组(n=39)。通过DECT重建虚拟非对比(VNC)和虚拟单能(VM)图像计算NWU。采用受试者工作特征(ROC)曲线分析诊断效能。将NWU与组织窗体积进行相关性分析。结果:获益组患者入院时美国国立卫生研究院卒中量表(NHISS)评分低于非获益组(14 vs 16,P=0.003)。NWU可有效识别有组织窗的患者,VM图像(60 keV)的NWU表现最佳,ROC曲线下面积(AUC)为0.812,准确度82.79%,灵敏度80.46%,特异度88.57%。NWU与组织窗体积呈负相关(rs=-0.57,P<0.001)。结论:DECT重建图对缺血脑组织NWU量化分析,有助于识别可能从溶栓治疗中获益的AIS患者,VM(60 keV)图像诊断效能最优。展开更多
Droughts impact forests by influencing various processes such as canopy greenness,tree growth,and reproduction,but most studies have only examined a few of these processes.More comprehensive assessments of forest resp...Droughts impact forests by influencing various processes such as canopy greenness,tree growth,and reproduction,but most studies have only examined a few of these processes.More comprehensive assessments of forest responses to climate variability and water shortages are needed to improve forecasts of post-drought dynamics.Iberian forests are well-suited for evaluating these effects because they experience diverse climatic conditions and are dominated by various conifer and broadleaf species,many of which exhibit masting.We assessed how greenness,evaluated using the normalized difference vegetation index(NDVI),tree radial growth,and seed or cone production responded to drought in five tree species(three conifers:silver fir(Abies alba),Scots pine(Pinus sylvestris),and stone pine(Pinus pinea);two broadleaves:European beech(Fagus sylvatica)and holm oak(Quercus ilex)inhabiting sites with different aridity.We correlated these data with the standardized precipitation evapotranspiration index(SPEI)using the climate window analysis(climwin)package,which identifies the most relevant climate window.Drought constrained growth more than greenness and seed or cone production.Dry conditions led to high seed or cone production in species found in cool,moist sites(silver fir,beech,and Scots pine).We also found negative associations of cone production with summer SPEI in the drought-tolerant stone pine,which showed lagged growth-cone negative correlations.However,in the seasonally dry holm oak forests,severe droughts constrained both growth and acorn production,leading to a positive correlation between these variables.Drought impacts on greenness,growth,seed,and cone production depended on species phenology and site aridity.A negative correlation between growth and reproduction does not necessarily indicate trade-offs,as both may be influenced by similar climatic factors.展开更多
文摘Palladium-based catalysts have long been considered the benchmark for methane combustion;however,the authentic phase of catalytic active sites remains a subject of ongoing debate.Additionally,challenges like water-poisoning and long-term stability need to be addressed to advance catalyst performance.Herein,we investigate Pd on Co_(3)O_(4) nanorods as a highly effective catalyst for catalytic oxidation of methane,demonstrating long-term stability and water tolerance during a 100-h continuous operation at 350℃.Comprehensive characterizations reveal the presence of an active Pd-oxygen vacancy(Ov)-cobalt interface in Pd/Co_(3)O_(4),which effectively adsorbs molecular O_(2).The absorbed oxygen species on this interface are activated and directly participate in methane combustion.Moreover,near-ambient pressure X-ray photoelectron spectroscopy demonstrates that Pd nanoparticles undergo a rapid phase transition and predominantly remain in the metallic state during the reaction.This behavior is attributed to the electronic metal-support interaction between Pd and Co_(3)O_(4).Furthermore,in situ Fourier transformed infrared spectrum reveals that under reaction conditions,HCO3*species are formed initially and subsequently transformed into formate species,indicating that the formate pathway is the dominant mechanism for CH_(4) oxidation.
基金Project supported by the National Natural Science Foundation of China(62105333)the Key Research Program of the Chinese Academy of Sciences(ZDRW-CN-2021-3)+1 种基金Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2020ZZ114)the Xiamen Medical and Health Guidance Project,China(3502Z20209124)。
文摘In recent years,persistent luminescence materials(PLMs)excited by X-rays and emitting in biological windows have received extensive attention in the field of high-sensitivity bioimaging.Transition metal Mn^(2+)is an ideal emission center,but few studies focus on Mn^(2+)-doped PLMs with X-ray excitation and biological window emission.Here,we report a Mn^(2+)-doped PLM,LiYGeO_(4):Mn^(2+)(LYGM),with excellent biological window persistent luminescence emission.After excitation by UV,LYGM produces a durable biological window of persistent luminescence emission at 660 nm for up to 20 h.More importantly.LYGM can be repeatedly excited by X-rays,resulting in long-term biological window persistent luminescence emission.In addition,we obtain LYGM around 200 nm in diameter by ball milling and centrifugation and improve its biocompatibility by surface modification to apply it to in vivo imaging in mice.After LYGM are injected into mice through the tail vein,in situ excitation of X-rays can be achieved.After the persistent luminescence decays,LYGM can be re-excited for repeated imaging.Therefore,LYGM shows potential prospects for in vivo deep tissue and long-term bioimaging.
文摘For many water quality studies,a data analyst,or modeler, may need to know the spatio-temproal patterns of the data sets and their relationships in both pre-processing and post-processing. Geographic Information System(GIS) can provide an exploratory spat
基金supported by the Longkou City Science and Technology Research and Development Plan(No.2020KJJH061).
文摘Developing supercapacitors(SCs)with long cycling life and wide operative voltage window is a significant topic in the field of aqueous electrolytes.Although the design of water in salt(WIS)electrolytes has pushed the development of aqueous electrolytes to a new height,the WIS electrolytes with an operative voltage window of up to 2.5 V is still very scarce.Herein,in order to enrich the type of aqueous electrolyte with high operative voltage,tetramethylammonium trifluoromethanesulfonate(TMAOTf)based WIS electrolyte was used as a model to construct WIS based hybrid electrolyte with acetonitrile(ACN)co-solvent and LiTFSI co-solute.In view of the coordination effect of ACN and Lit on free water in TMAOTf based WIS electrolyte,the TMAt-Lit-AWIS electrolyte has the electrochemical stabilization window of up to 3.35 V.Further coupled with the commercial YP-50F electrodes,TMAt-Lit-AWIS based SCs exhibited wide operative voltage window(2.5 V),long cycling life(45,000 cycles)and good low-temperature performance(99.99%capacitance retention after 2000 cycles at20℃).The design of this hybrid electrolyte will enrich the types of aqueous hybrid electrolytes with long cycling life and wide operative voltage window.
基金supported by the National Major Scientific Research Instrument Development Projects(No.42127807)the National Natural Science Foundation of China(No.12105030)。
文摘Promoting the development of deep-sea mineral exploration instrumentation can help alleviate the global resource shortage faced by mankind.X-ray fluorescence(XRF)spectrometry has been widely used in the in situ analysis of deep-sea minerals owing to its fast analytical speed,nondestructive nature,and wide analytical range.This study focused on the structural safety and detection efficiency of X-ray fluorescence in situ measurement equipment under high pressure for deep-sea XRF analysis.This study first combined finite element analysis and experiments to design and optimize the structure of an X-ray probe tube required for deep-sea mineral exploration and to determine the Be window thickness to ensure stress safety.Subsequently,the Monte Carlo method was used to analyze and optimize the Be window thickness on the X-ray probe tube to improve the accuracy of the elemental analyses.Finally,the effect of seawater thickness between the transmitter outer tube and rock wall was also considered.The results show that based on ocean depth in different detection environments,Be windows with a thickness of 1.5 mm or 2.0 mm can be selected to improve the detection efficiency of the device while ensuring the structural safety of the instrument.According to the design features and detection requirements of the device,in deep-sea exploration of minerals with characteristic peak energies below 10 keV,the transmitter outer tube should be as close as possible to the rock wall inside the logging.When the characteristic peak energy of the minerals is more than 10 keV,the distance between the transmitter outer tube and rock wall inside the logging should be controlled to approximately 2 mm.This study provides feasible solutions for future deep-sea mineral resource development and a useful reference for elemental analysis of minerals in the deep-sea or other extreme working environments.
文摘目的:探讨双能CT(DECT)重建图量化缺血脑组织净水摄取值(NWU)在评估急性缺血性卒中(AIS)患者组织窗的价值。方法:回顾性收集2016年12月至2022年5月期间接受DECT和CT灌注(CTP)的122例AIS患者资料,根据CTP将其分为获益组(n=83)及非获益组(n=39)。通过DECT重建虚拟非对比(VNC)和虚拟单能(VM)图像计算NWU。采用受试者工作特征(ROC)曲线分析诊断效能。将NWU与组织窗体积进行相关性分析。结果:获益组患者入院时美国国立卫生研究院卒中量表(NHISS)评分低于非获益组(14 vs 16,P=0.003)。NWU可有效识别有组织窗的患者,VM图像(60 keV)的NWU表现最佳,ROC曲线下面积(AUC)为0.812,准确度82.79%,灵敏度80.46%,特异度88.57%。NWU与组织窗体积呈负相关(rs=-0.57,P<0.001)。结论:DECT重建图对缺血脑组织NWU量化分析,有助于识别可能从溶栓治疗中获益的AIS患者,VM(60 keV)图像诊断效能最优。
基金funded by the Science and Innovation Ministry of Spain(projects AGL 2012-33465,AGL 2016-76463-P,PID 2021-123675OB-C43,and TED 2021-129770B-C21)support by Margarita Salas postdoctoral fellowship(reference RCMS-22-G1T6IW-17-NLHJ80)of the Universidad Politécnica de Madrid
文摘Droughts impact forests by influencing various processes such as canopy greenness,tree growth,and reproduction,but most studies have only examined a few of these processes.More comprehensive assessments of forest responses to climate variability and water shortages are needed to improve forecasts of post-drought dynamics.Iberian forests are well-suited for evaluating these effects because they experience diverse climatic conditions and are dominated by various conifer and broadleaf species,many of which exhibit masting.We assessed how greenness,evaluated using the normalized difference vegetation index(NDVI),tree radial growth,and seed or cone production responded to drought in five tree species(three conifers:silver fir(Abies alba),Scots pine(Pinus sylvestris),and stone pine(Pinus pinea);two broadleaves:European beech(Fagus sylvatica)and holm oak(Quercus ilex)inhabiting sites with different aridity.We correlated these data with the standardized precipitation evapotranspiration index(SPEI)using the climate window analysis(climwin)package,which identifies the most relevant climate window.Drought constrained growth more than greenness and seed or cone production.Dry conditions led to high seed or cone production in species found in cool,moist sites(silver fir,beech,and Scots pine).We also found negative associations of cone production with summer SPEI in the drought-tolerant stone pine,which showed lagged growth-cone negative correlations.However,in the seasonally dry holm oak forests,severe droughts constrained both growth and acorn production,leading to a positive correlation between these variables.Drought impacts on greenness,growth,seed,and cone production depended on species phenology and site aridity.A negative correlation between growth and reproduction does not necessarily indicate trade-offs,as both may be influenced by similar climatic factors.
