Uncertainties about natural gas source and hydrocarbon accumulation seriously restrict oil and gas exploration in the Lianggaoshan Formation(J_(2) l)in the Eastern Sichuan Basin,which has demonstrated great exploratio...Uncertainties about natural gas source and hydrocarbon accumulation seriously restrict oil and gas exploration in the Lianggaoshan Formation(J_(2) l)in the Eastern Sichuan Basin,which has demonstrated great exploration potential in recent years.This study determines the origin of natural gas and the hydrocarbon accumulation model of J_(2) l in the Eastern Sichuan Basin.A new sample pretreatment method named gas purge-microsyringe extraction was employed and confi rmed to be a practical and eff ective method for preparing condensate oil and collecting source rock extract samples.The source rocks of J_(2) l exhibited moderate to good qualities,characterized by high TOC values,dominance of type Ⅱ_(1) and Ⅱ_(2) kerogens,and high thermal maturities.Biomarker and aromatic characteristics revealed that the source rocks of J_(2) l were deposited in brackish water with weak anoxic conditions.The natural gas in J_(2) l was an organic thermogenic gas generated from the secondary cracking of crude oil,indicating that this natural gas was mainly derived from the source rocks of J_(2) l.The condensate oil-source rock correlation further confi rmed the accuracy of the gas-source correlation results.Based on burial,thermal and hydrocarbon-generating histories,two hydrocarbon charging periods(141–133 Ma and 119–112 Ma)and four hydrocarbon accumulation periods of J_(2) l were determined.Combined with structural evolution,depositional histories and reservoir conditions,a simple gas reservoir accumulation model of J_(2) l was developed,which was identifi ed as a“self-generating and self-storing”gas reservoir.展开更多
The deep-water systems in different types of sedimentary basins exhibit significant variability.Current knowledge of deep-water deposition is mainly derived from deep-marine turbidite systems.However,the characteristi...The deep-water systems in different types of sedimentary basins exhibit significant variability.Current knowledge of deep-water deposition is mainly derived from deep-marine turbidite systems.However,the characteristics and differences of sub-lacustrine gravity flow deposition systems have been a research focus in the fields of sedimentology and petroleum geology.This study investigates the facies archi-tecture,depositional processes,and sediment distribution patterns of a sub-lacustrine debrite system in the Eocene Dongying Rift of the Bohai Bay Basin,China,through the analysis of integrated core data,3-D seismic data,and well-log data.Nine facies have been identified within the debrite system,representing various depositional processes such as sandy debris flow,muddy debris flow,turbidity currents,sandy slide,sandy slide/slump,and mud flow.Our research indicates that the sub-lacustrine system is primarily influenced by debris flow rather than turbidity currents,as supported by facies quantification,inter-pretation,and flow rheology analysis.Additionally,we have identified five basic facies building blocks in debrite systems,including slide masses,slump masses,debrite channels,debrite lobes,and turbidite sheets.We have also elucidated and proposed detailed sedimentary processes,flow transport,and transformation within the sub-lacustrine system through analysis of flow origins,facies sequences,and distribution characteristics.Our findings highlight the evolutionary progression from delta-front collapse to sandy slide/slump,sandy debris flow,and finally muddy debris flow.The efficient generation of turbidity currents from parental landslides on sand-prone slopes is deemed unlikely due to rift-basin morphology and transport distances.The formation of the five basic facies building blocks is closely linked to depositional processes and dominant flow types.Consequently,we present a deep-water depositional model for sub-lacustrine debrite systems,focusing on flow dynamics,sediment distribu-tion patterns,and basin morphology within deep lacustrine rifts.This model offers valuable insights into the variability of deep-water deposition in diverse basin settings and aids in predicting lithologic res-ervoirs during deep-water hydrocarbon exploration.展开更多
La0.8Pr0.2MgNi3.6Co0.4 alloys were prepared by induction melting,annealing and melt spinning techniques.The influences of annealing treatment and melt spinning on phase structure and hydrogen storage properties were s...La0.8Pr0.2MgNi3.6Co0.4 alloys were prepared by induction melting,annealing and melt spinning techniques.The influences of annealing treatment and melt spinning on phase structure and hydrogen storage properties were systematically investigated.The results of X-ray diffraction determine that the as-cast and as-spun La0.8Pr0.2MgNi3.6Co0.4 alloys consist of LaMgNi4 and LaNi5 phases,while only LaMgNi4 phase is present in the as-annealed alloy.The scanning electron microscope images illustrate that the grain of the alloy is significantly refined by melt spin ning tech no logy.The gaseous hydrogen storage kinetic and thermodynamic properties were measured by using a Sievert's apparatus at different temperatures.The maximum hydrogen storage capacity of the as-cast,as?spun and as-annealed La0.8Pr0.2MgNi3.6Co0.4 alloy is 1.699,1.637 and 1.535 wt.% at 373 K and 3 MPa,respectively.The annealed alloy has flatter and wider pressure plateaus compared with the as-cast and as-spun alloys,which correspond to the hydrogen absorption and desorption process of LaMgNi4 and corresponding hydride.Furthermore,the enthalpy and entropy changes of LaMgNi4 during hydrogenation at different temperatures were calculated using Van't Hoff methods.展开更多
V48Fe12Ti15Cr25 alloy was prepared using vacuum arc melting and was subsequently annealed for 10 h at 1273 K.The effects of annealing on the hydrogen storage properties and microstructure of the V48Fe12Ti15Cr25 alloys...V48Fe12Ti15Cr25 alloy was prepared using vacuum arc melting and was subsequently annealed for 10 h at 1273 K.The effects of annealing on the hydrogen storage properties and microstructure of the V48Fe12Ti15Cr25 alloys were investigated.The results indicated that the alloy consisted of main body-centered cubic,Ti-rich,and TiFe phases.After annealing,the kinetic properties of the alloy were improved but its hydrogen storage capacity was slightly reduced.The kinetic mechanisms of the hydrogen absorption and desorption of the alloys were studied.The dehydrogenation enthalpy of the alloy was decreased by 2.57 kJ/mol after annealing.Differential scanning calorimetry indicated that the hydride decomposition temperature of the annealed alloy was decreased.The hydrogen desorption activation energies of the as-cast and annealed alloys were calculated to be 79.41 and 71.25 kJ/mol,respectively.The results illustrated that annealing was a beneficial method of improving the kinetic and thermodynamic properties of the hydrogen absorption/desorption of the alloy.展开更多
Perovskite nanocrystals(PNCs)have recently become promising optoelectronic materials due to their excellent photophysical properties.However,the highly dynamic binding state between ligands and the surface of PNCs has...Perovskite nanocrystals(PNCs)have recently become promising optoelectronic materials due to their excellent photophysical properties.However,the highly dynamic binding state between ligands and the surface of PNCs has severely restricted their luminescent properties and stabilities.In this work,1,3-bisbenzyl-2-oxoimidazolidine-4,5-dicarboxylic acid(cycle acid,CA)is introduced as both an etchant and a ligand upon post-synthetic surface treatment of PNCs.By removing the imperfect octahedrons[Pb X_(6)]^(4-)and passivating the surface defects synergistically,this treatment improves photoluminescence quantum yields from 76%to 95%and enhances the stability of PNCs against polar solvent,moisture,heat,and illumination.Meanwhile,CA can effectively and instantly recover the luminescence emission for aged PNCs.As a result,the CA-Cs Pb Br_(3)PNCs and CA-Cs Pb IxBr_(3-x)PNCs are applied as color-converting layers on a blue LED chip for warm white light-emitting diodes(WLEDs)with a color coordinate of(0.41,0.40).Importantly,the CA-based WLED device exhibits superior stability in operational conditions.展开更多
Cloud platforms could automatically scale underlying network resources up and down in response to changes in the traffic load.Such an auto-scaling mechanism can largely enhance the elasticity and scalability of cloud ...Cloud platforms could automatically scale underlying network resources up and down in response to changes in the traffic load.Such an auto-scaling mechanism can largely enhance the elasticity and scalability of cloud platforms.However,it may introduce new security threats.For example,the Yo-Yo attack is a newly disclosed attack against the cloud auto-scaling mechanism.Attackers periodically send bursts of traffic to cause the autoscaling mechanism to oscillate between the scale-up process and the scale-down process,which may result in significant performance degradation and economic loss.None of the prior work addressed the problem of mitigating such an attack.In this paper,we propose a Trust-based Adversarial Scanner Delaying(TASD)approach to effectively and proactively mitigate the Yo-Yo attack on the cloud auto-scaling mechanism.In TASD,we first propose to use the trust-based scheme to establish trust values for users,which is leveraged to identify adversarial requests.Trust values are updated by jointly considering the request mode and the auto-scaling status.Then,we aim to disable the condition under which the Yo-Yo attack takes effect by injecting certain delay,under the QoS constraints,to manipulate the response time of suspicious requests and deceive the attackers.Our extensive evaluation demonstrates that our approach achieves promising results,e.g.,it can detect at least 80%Yo-Yo adversarial users and reduce more than 41%malicious scale-ups.展开更多
Organic-inorganic hybrid perovskite materials have recently attracted extensive attentions because of their intriguing optoelectronic properties for photovoltaics[1],[2],[3].The power conversion efficiency(PCE)of pero...Organic-inorganic hybrid perovskite materials have recently attracted extensive attentions because of their intriguing optoelectronic properties for photovoltaics[1],[2],[3].The power conversion efficiency(PCE)of perovskite solar cells(PSCs)experienced an incredible rise from 3.8%to 25.5%within a decade.展开更多
High-entropy alloys(HEAs)are a promising solution for large-scale hydrogen storage(H-storage)and are therefore receiving increasing attention from the materials science community.In this study,we systematically invest...High-entropy alloys(HEAs)are a promising solution for large-scale hydrogen storage(H-storage)and are therefore receiving increasing attention from the materials science community.In this study,we systematically investigated the microstructures and H-storage properties of V_(35)Ti_(35)Cr_(10) Fe_(10)M_(10)(M=Mn,Co,Sc,or Ni)HEAs prepared by arcmelting.The cast HEAs were found to be nanocrystalline.The crystal lattice parameters and hydrogen absorption energies of the alloys were calculated using density functional theory(DFT)calculations.The alloys can be fully activated in just one cycle of hydrogen absorption/desorption under mild conditions,after which they reach hydrogen absorption saturation in approximately 100 s at ambient temperature.The hydrogenation kinetics of the HEAs are approximately five times higher than that of conventional solid-solution alloys with a body-centered cubic(BCC)structure.By performing in-situ hydriding differential scanning calorimetry in combination with DFT calculations,we revealed that the alloys are more susceptible to hydrogenation than traditional BCC structural alloys.The H-storage capacity of V_(35)Ti_(35)Cr_(10) Fe_(10)M_(10) alloys at ambient temperature was higher than that of HEAs reported in the literature.Quasi-in-situ X-ray diffraction characterization of the HEAs’hydrogenation revealed a phase transition process from a BCC to facecentered cubic,passing through a pseudo-BCC structure.Our work introduces a new perspective for designing alloys with ultrafast hydrogen absorption kinetics and high capacity for large-scale,room-temperature-applicable H-storage.展开更多
The positive S-isotopic excursion of carbonate-associated sulfate(δ34S_(CAS))is generally in phase with the Steptoean positive carbon isotope excursion(SPICE),which may reflect widespread,global,transient increases i...The positive S-isotopic excursion of carbonate-associated sulfate(δ34S_(CAS))is generally in phase with the Steptoean positive carbon isotope excursion(SPICE),which may reflect widespread,global,transient increases in the burial of organic carbon and pyrite sulfate in sediments deposited under large-scale anoxic and sulphidic conditions.However,carbon-sulfur isotope cycling of the global SPICE event,which may be controlled by global and regional events,is still poorly understood,especially in south China.Therefore,theδ13CPDB,δ18OPDBδ34S_(CAS),total carbon(TC),total organic carbon(TOC)and total sulfate(TS)of Cambrian carbonate of Waergang section of Hunan Province were analyzed to unravel global and regional controls on carbon-sulfur cycling during SPICE event in south China.Theδ34S_(CAS)values in the onset and rising limb are not obviously higher than that in the preceding SPICE,meanwhile sulfate(δ34S_(CAS))isotope values increase slightly with increasingδ13CPDB in rising limb and near peak of SPICE(130–160 m).The sulfate(δ34S_(CAS))isotope values gradually decrease from 48.6‰to 18‰in the peak part of SPICE and even increase from 18%to 38.5%in the descending limb of SPICE.The abnormal asynchronous C−S isotope excursion during SPICE event in the south China was mainly controlled by the global events including sea level change and marine sulfate reduction,and it was also influenced by regional events such as enhanced siliciclastic provenance input(sulfate),weathering of a carbonate platform and sedimentary environment.Sedimentary environment and lithology are not the main reason for global SPICE event but influence theδ13CPDB excursion-amplitude of SPICE.Sea level eustacy and carbonate platform weathering probably made a major contribution to theδ13CPDB excursion during the SPICE,in particularly,near peak of SPICE.Besides,the trilobite extinctions,anoxia,organic-matter burial and siliciclastic provenance input also play an important role in the onset,early and late stage of SPICE event.展开更多
Here,we report a Pd/PdO_(x) sensing material that achieves 1-s detection of 4% H_(2) gas(i.e.,the lower explosive limit concentration for H_(2))at room temperature in air.The Pd/PdO_(x) material is a network of interc...Here,we report a Pd/PdO_(x) sensing material that achieves 1-s detection of 4% H_(2) gas(i.e.,the lower explosive limit concentration for H_(2))at room temperature in air.The Pd/PdO_(x) material is a network of interconnected nanoscopic domains of Pd,PdO,and PdO_(2).Upon exposure to 4% H_(2),PdO and PdO_(2) in the Pd/PdO_(x) are immediately reduced to metallic Pd,generating over a>90% drop in electrical resistance.The mechanistic study reveals that the Pd/PdO_(2) interface in Pd/PdOx is responsible for the ultrafast PdO_(x) reduction.Metallic Pd at the Pd/PdO_(2) interface enables fast H_(2) dissociation to adsorbed H atoms,significantly lowering the PdO2 reduction barrier.In addition,control experiments suggest that the interconnectivity of Pd,PdO,and PdO2 in our Pd/PdO_(x) sensing material further facilitates the reduction of PdO,which would otherwise not occur.The 1-s response time of Pd/PdO_(x) under ambient conditions makes it an excellent alarm for the timely detection of hydrogen gas leaks.展开更多
基金supported by the grants from the National Natural Science Foundation of China(grant nos.41902153,42072140,42102133 and 42202170)Natural Science Foundation Project of Chongqing(grant nos.cstc2021jcyj-msxmX0455,CSTB2022NSCQ-JQX0031 and CSTB2022NSCQ-MSX1586)Science and Technology Research Program of Chongqing Municipal Education Commission(grant nos.KJQN202101544,KJZD-M202101502).
文摘Uncertainties about natural gas source and hydrocarbon accumulation seriously restrict oil and gas exploration in the Lianggaoshan Formation(J_(2) l)in the Eastern Sichuan Basin,which has demonstrated great exploration potential in recent years.This study determines the origin of natural gas and the hydrocarbon accumulation model of J_(2) l in the Eastern Sichuan Basin.A new sample pretreatment method named gas purge-microsyringe extraction was employed and confi rmed to be a practical and eff ective method for preparing condensate oil and collecting source rock extract samples.The source rocks of J_(2) l exhibited moderate to good qualities,characterized by high TOC values,dominance of type Ⅱ_(1) and Ⅱ_(2) kerogens,and high thermal maturities.Biomarker and aromatic characteristics revealed that the source rocks of J_(2) l were deposited in brackish water with weak anoxic conditions.The natural gas in J_(2) l was an organic thermogenic gas generated from the secondary cracking of crude oil,indicating that this natural gas was mainly derived from the source rocks of J_(2) l.The condensate oil-source rock correlation further confi rmed the accuracy of the gas-source correlation results.Based on burial,thermal and hydrocarbon-generating histories,two hydrocarbon charging periods(141–133 Ma and 119–112 Ma)and four hydrocarbon accumulation periods of J_(2) l were determined.Combined with structural evolution,depositional histories and reservoir conditions,a simple gas reservoir accumulation model of J_(2) l was developed,which was identifi ed as a“self-generating and self-storing”gas reservoir.
基金supported by the National Natural Science Foundation of China(No.42202170,42172109,42072140,42102133,42202122)the Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX1166,CSTB2022NSCQ-JQX0031)+1 种基金the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202201511,KJZD-M202101502)Project of Chongqing University of Science&Technology(ckrc2022028,YKJCX2320109).
文摘The deep-water systems in different types of sedimentary basins exhibit significant variability.Current knowledge of deep-water deposition is mainly derived from deep-marine turbidite systems.However,the characteristics and differences of sub-lacustrine gravity flow deposition systems have been a research focus in the fields of sedimentology and petroleum geology.This study investigates the facies archi-tecture,depositional processes,and sediment distribution patterns of a sub-lacustrine debrite system in the Eocene Dongying Rift of the Bohai Bay Basin,China,through the analysis of integrated core data,3-D seismic data,and well-log data.Nine facies have been identified within the debrite system,representing various depositional processes such as sandy debris flow,muddy debris flow,turbidity currents,sandy slide,sandy slide/slump,and mud flow.Our research indicates that the sub-lacustrine system is primarily influenced by debris flow rather than turbidity currents,as supported by facies quantification,inter-pretation,and flow rheology analysis.Additionally,we have identified five basic facies building blocks in debrite systems,including slide masses,slump masses,debrite channels,debrite lobes,and turbidite sheets.We have also elucidated and proposed detailed sedimentary processes,flow transport,and transformation within the sub-lacustrine system through analysis of flow origins,facies sequences,and distribution characteristics.Our findings highlight the evolutionary progression from delta-front collapse to sandy slide/slump,sandy debris flow,and finally muddy debris flow.The efficient generation of turbidity currents from parental landslides on sand-prone slopes is deemed unlikely due to rift-basin morphology and transport distances.The formation of the five basic facies building blocks is closely linked to depositional processes and dominant flow types.Consequently,we present a deep-water depositional model for sub-lacustrine debrite systems,focusing on flow dynamics,sediment distribu-tion patterns,and basin morphology within deep lacustrine rifts.This model offers valuable insights into the variability of deep-water deposition in diverse basin settings and aids in predicting lithologic res-ervoirs during deep-water hydrocarbon exploration.
基金This work was financially supported by the National Natural Science Foundation of China(51901105,51871125 and 51761032)Inner Mongolia Natural Science Foundation(2017BS0507 and 2019BS05005)Inner Mongolia University of Science and Technology Innovation Fund(2016QDL-B02).
文摘La0.8Pr0.2MgNi3.6Co0.4 alloys were prepared by induction melting,annealing and melt spinning techniques.The influences of annealing treatment and melt spinning on phase structure and hydrogen storage properties were systematically investigated.The results of X-ray diffraction determine that the as-cast and as-spun La0.8Pr0.2MgNi3.6Co0.4 alloys consist of LaMgNi4 and LaNi5 phases,while only LaMgNi4 phase is present in the as-annealed alloy.The scanning electron microscope images illustrate that the grain of the alloy is significantly refined by melt spin ning tech no logy.The gaseous hydrogen storage kinetic and thermodynamic properties were measured by using a Sievert's apparatus at different temperatures.The maximum hydrogen storage capacity of the as-cast,as?spun and as-annealed La0.8Pr0.2MgNi3.6Co0.4 alloy is 1.699,1.637 and 1.535 wt.% at 373 K and 3 MPa,respectively.The annealed alloy has flatter and wider pressure plateaus compared with the as-cast and as-spun alloys,which correspond to the hydrogen absorption and desorption process of LaMgNi4 and corresponding hydride.Furthermore,the enthalpy and entropy changes of LaMgNi4 during hydrogenation at different temperatures were calculated using Van't Hoff methods.
基金National Natural Science Foundation of China(Grant No.51901105)Natural Science Foundation of Inner Mongolia,China(Grant Nos.2018LH05010,2019BS05005,and 2017BS0507).
文摘V48Fe12Ti15Cr25 alloy was prepared using vacuum arc melting and was subsequently annealed for 10 h at 1273 K.The effects of annealing on the hydrogen storage properties and microstructure of the V48Fe12Ti15Cr25 alloys were investigated.The results indicated that the alloy consisted of main body-centered cubic,Ti-rich,and TiFe phases.After annealing,the kinetic properties of the alloy were improved but its hydrogen storage capacity was slightly reduced.The kinetic mechanisms of the hydrogen absorption and desorption of the alloys were studied.The dehydrogenation enthalpy of the alloy was decreased by 2.57 kJ/mol after annealing.Differential scanning calorimetry indicated that the hydride decomposition temperature of the annealed alloy was decreased.The hydrogen desorption activation energies of the as-cast and annealed alloys were calculated to be 79.41 and 71.25 kJ/mol,respectively.The results illustrated that annealing was a beneficial method of improving the kinetic and thermodynamic properties of the hydrogen absorption/desorption of the alloy.
基金financial from the National Natural Science Foundation of China(22279039 and 20181194)the Chinese National 1000-Talent-Plan program+2 种基金the Innovation Project of Optics Valley Laboratory(OVL2021BG008)the Frontier of the Application Foundation of Wuhan Science and Technology Plan Project(2020010601012202)the Foundation of State Key Laboratory of New Textile Materials and Advanced Processing Technologies(FZ2021011)。
文摘Perovskite nanocrystals(PNCs)have recently become promising optoelectronic materials due to their excellent photophysical properties.However,the highly dynamic binding state between ligands and the surface of PNCs has severely restricted their luminescent properties and stabilities.In this work,1,3-bisbenzyl-2-oxoimidazolidine-4,5-dicarboxylic acid(cycle acid,CA)is introduced as both an etchant and a ligand upon post-synthetic surface treatment of PNCs.By removing the imperfect octahedrons[Pb X_(6)]^(4-)and passivating the surface defects synergistically,this treatment improves photoluminescence quantum yields from 76%to 95%and enhances the stability of PNCs against polar solvent,moisture,heat,and illumination.Meanwhile,CA can effectively and instantly recover the luminescence emission for aged PNCs.As a result,the CA-Cs Pb Br_(3)PNCs and CA-Cs Pb IxBr_(3-x)PNCs are applied as color-converting layers on a blue LED chip for warm white light-emitting diodes(WLEDs)with a color coordinate of(0.41,0.40).Importantly,the CA-based WLED device exhibits superior stability in operational conditions.
基金This research was partially supported by the Natural Science Foundation of China(61571098)Open Foundation of State Key Laboratory of Networking and Switching Technology(Beijing University of Posts and Telecommunications)(SKLNST-2016-2-24).
文摘Cloud platforms could automatically scale underlying network resources up and down in response to changes in the traffic load.Such an auto-scaling mechanism can largely enhance the elasticity and scalability of cloud platforms.However,it may introduce new security threats.For example,the Yo-Yo attack is a newly disclosed attack against the cloud auto-scaling mechanism.Attackers periodically send bursts of traffic to cause the autoscaling mechanism to oscillate between the scale-up process and the scale-down process,which may result in significant performance degradation and economic loss.None of the prior work addressed the problem of mitigating such an attack.In this paper,we propose a Trust-based Adversarial Scanner Delaying(TASD)approach to effectively and proactively mitigate the Yo-Yo attack on the cloud auto-scaling mechanism.In TASD,we first propose to use the trust-based scheme to establish trust values for users,which is leveraged to identify adversarial requests.Trust values are updated by jointly considering the request mode and the auto-scaling status.Then,we aim to disable the condition under which the Yo-Yo attack takes effect by injecting certain delay,under the QoS constraints,to manipulate the response time of suspicious requests and deceive the attackers.Our extensive evaluation demonstrates that our approach achieves promising results,e.g.,it can detect at least 80%Yo-Yo adversarial users and reduce more than 41%malicious scale-ups.
基金financial support from the National Key Research and Development Program of China(2018YFB1500104)the National Natural Science Foundation of China(51972251,51702243,and 91963209)+1 种基金Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory(XHD2020-001)the Fundamental Research Funds for the Central Universities(2020Ⅲ0242D)
文摘Organic-inorganic hybrid perovskite materials have recently attracted extensive attentions because of their intriguing optoelectronic properties for photovoltaics[1],[2],[3].The power conversion efficiency(PCE)of perovskite solar cells(PSCs)experienced an incredible rise from 3.8%to 25.5%within a decade.
基金supported by the Natural Science Foundation of Inner Mongolia,China(grant nos.2022MS05011,2020LH01006,and 2022FX02)the National Natural Science Foundation of China(grant nos.52261041 and 51961032)+1 种基金the Major Science and Technology Project of Inner Mongolia(grant no.2021ZD0029)the Fundamental Research Funds for Inner Mongolia University of Science&Technology(grant no.2023QNJS119).
文摘High-entropy alloys(HEAs)are a promising solution for large-scale hydrogen storage(H-storage)and are therefore receiving increasing attention from the materials science community.In this study,we systematically investigated the microstructures and H-storage properties of V_(35)Ti_(35)Cr_(10) Fe_(10)M_(10)(M=Mn,Co,Sc,or Ni)HEAs prepared by arcmelting.The cast HEAs were found to be nanocrystalline.The crystal lattice parameters and hydrogen absorption energies of the alloys were calculated using density functional theory(DFT)calculations.The alloys can be fully activated in just one cycle of hydrogen absorption/desorption under mild conditions,after which they reach hydrogen absorption saturation in approximately 100 s at ambient temperature.The hydrogenation kinetics of the HEAs are approximately five times higher than that of conventional solid-solution alloys with a body-centered cubic(BCC)structure.By performing in-situ hydriding differential scanning calorimetry in combination with DFT calculations,we revealed that the alloys are more susceptible to hydrogenation than traditional BCC structural alloys.The H-storage capacity of V_(35)Ti_(35)Cr_(10) Fe_(10)M_(10) alloys at ambient temperature was higher than that of HEAs reported in the literature.Quasi-in-situ X-ray diffraction characterization of the HEAs’hydrogenation revealed a phase transition process from a BCC to facecentered cubic,passing through a pseudo-BCC structure.Our work introduces a new perspective for designing alloys with ultrafast hydrogen absorption kinetics and high capacity for large-scale,room-temperature-applicable H-storage.
基金the open fund of State Key Laboratory of Biogeology and Environmental Geology(No.GBL21506)the National Natural Science Foundation of China(Grant Nos.42072140 and 42102133)+2 种基金Chongqing Natural Science Foundation of China(No.cstc2020jcyj msxmX0217)Science and Technology Research Program of Chongqing Municipal Education Commission(Nos.KJZD-M202101502 and KJQN202001517)Chongqing University of Science and Technology(No.ckrc2019035).
文摘The positive S-isotopic excursion of carbonate-associated sulfate(δ34S_(CAS))is generally in phase with the Steptoean positive carbon isotope excursion(SPICE),which may reflect widespread,global,transient increases in the burial of organic carbon and pyrite sulfate in sediments deposited under large-scale anoxic and sulphidic conditions.However,carbon-sulfur isotope cycling of the global SPICE event,which may be controlled by global and regional events,is still poorly understood,especially in south China.Therefore,theδ13CPDB,δ18OPDBδ34S_(CAS),total carbon(TC),total organic carbon(TOC)and total sulfate(TS)of Cambrian carbonate of Waergang section of Hunan Province were analyzed to unravel global and regional controls on carbon-sulfur cycling during SPICE event in south China.Theδ34S_(CAS)values in the onset and rising limb are not obviously higher than that in the preceding SPICE,meanwhile sulfate(δ34S_(CAS))isotope values increase slightly with increasingδ13CPDB in rising limb and near peak of SPICE(130–160 m).The sulfate(δ34S_(CAS))isotope values gradually decrease from 48.6‰to 18‰in the peak part of SPICE and even increase from 18%to 38.5%in the descending limb of SPICE.The abnormal asynchronous C−S isotope excursion during SPICE event in the south China was mainly controlled by the global events including sea level change and marine sulfate reduction,and it was also influenced by regional events such as enhanced siliciclastic provenance input(sulfate),weathering of a carbonate platform and sedimentary environment.Sedimentary environment and lithology are not the main reason for global SPICE event but influence theδ13CPDB excursion-amplitude of SPICE.Sea level eustacy and carbonate platform weathering probably made a major contribution to theδ13CPDB excursion during the SPICE,in particularly,near peak of SPICE.Besides,the trilobite extinctions,anoxia,organic-matter burial and siliciclastic provenance input also play an important role in the onset,early and late stage of SPICE event.
基金The work at Wayne State University and the Pacific Northwest National Laboratory was supported by the U.S.Department of Energy(DOE),Office of Science,Office of Basic Energy Sciences,through Award#78705In addition,L.L.and X.G.acknowledge support from National Science Foundation under award CHE-1943737.L.Z.and S.W.L.acknowledge support from the National Natural Science Foundation of China(No.22103047)Hefei National Laboratory for Physical Sciences at the Microscale(No.KF2020107).
文摘Here,we report a Pd/PdO_(x) sensing material that achieves 1-s detection of 4% H_(2) gas(i.e.,the lower explosive limit concentration for H_(2))at room temperature in air.The Pd/PdO_(x) material is a network of interconnected nanoscopic domains of Pd,PdO,and PdO_(2).Upon exposure to 4% H_(2),PdO and PdO_(2) in the Pd/PdO_(x) are immediately reduced to metallic Pd,generating over a>90% drop in electrical resistance.The mechanistic study reveals that the Pd/PdO_(2) interface in Pd/PdOx is responsible for the ultrafast PdO_(x) reduction.Metallic Pd at the Pd/PdO_(2) interface enables fast H_(2) dissociation to adsorbed H atoms,significantly lowering the PdO2 reduction barrier.In addition,control experiments suggest that the interconnectivity of Pd,PdO,and PdO2 in our Pd/PdO_(x) sensing material further facilitates the reduction of PdO,which would otherwise not occur.The 1-s response time of Pd/PdO_(x) under ambient conditions makes it an excellent alarm for the timely detection of hydrogen gas leaks.
