Understanding water dynamics under the effect of climatic conditions is important to improve water sustainability over the medium-and long-term.Clay content can affect soil hydrothermal properties,and hence modify wat...Understanding water dynamics under the effect of climatic conditions is important to improve water sustainability over the medium-and long-term.Clay content can affect soil hydrothermal properties,and hence modify water and heat exchange between soil and atmosphere,e.g.evapotranspiration and infiltration.This work aims to develop a numerical approach to explore the influence of clay content on soil hydrothermal response to the timely climatic conditions in the Lake Chad region,Sahel Region of west-central Africa.The meteorological information at the studied points,i.e.points A and B with a clay content of 8.3%and 25%,during the year 2008 is collected from ERA5-Land hourly data.The numerical results allow for understanding the effect of clay content on the hydrothermal response of the surface soil layer.Specifically,the soil surface temperature under point A is lower than that under point B during the dry season due to the dominant effect of heat conduction.However,the converse tendency is observed during the wet season because of the combined effect of heat conduction and latent heat.The variations of soil volumetric water content are closely related to the timely interaction between the soil and atmosphere,in addition to the hydrothermal properties of soil.Moreover,the outcomes of this work improve the understanding of the heat and water dynamics under the effect of climatic conditions and clay content,and provide further insights into the potential water protection in arid and semi-arid regions in the future.展开更多
The recognition and monitoring of localized corrosion at the early stage on the inner wall surface of pipes are extremely difficult and simultaneously the reliable approach for recognition and monitoring is missing.He...The recognition and monitoring of localized corrosion at the early stage on the inner wall surface of pipes are extremely difficult and simultaneously the reliable approach for recognition and monitoring is missing.Here we report a spatially resolved method to recognize and monitor the localized corrosion in a non-destructive way based on the permeating hydrogen signal generated from localized corrosion itself.A simulative localized corrosion was created on one side surface of the carbon steel specimen where a dot of wet elemental sulfur was introduced to accelerate the corrosion on the local region.While,the potential on the other side surface(the reverse side of the corrosion site)of the specimen was measured using a scanning Kelvin probe.The results show that the permeating hydrogen generated from localized corrosion easily arrives on the reverse side surface of the corrosion site and then causes a huge change in surface potential.The location resolution of potential distribution can be revealed with micron level.Therefore,it is thought that the location of localized corrosion can be recognized by the permeating hydrogen signal distribution on the reverse side surface of the corrosion site since the region of potential decreasing is highly corresponding to the corrosion site.Moreover,the strength of the permeating hydrogen signal is highly related to the corrosion depth and transient corrosion rate of localized corrosion.This means that the localized corrosion development can also be monitored using the permeating hydrogen signal.Therefore,it can be expected that the localized corrosion occurring on the inner wall surface of pipes or equipment can be recognized and monitored successfully on the outer wall surface in a non-destructive way once the permeating hydrogen is present during the localized corrosion proceeding.展开更多
Covalent organic frameworks(COFs)are newly developed crystalline substances that are garnering growing interest because of their ultrahigh porosity,crystalline nature,and easy-modified architecture,showing promise in ...Covalent organic frameworks(COFs)are newly developed crystalline substances that are garnering growing interest because of their ultrahigh porosity,crystalline nature,and easy-modified architecture,showing promise in the field of photocatalysis.However,it is difficult for pure COFs materials to achieve excellent photocatalytic hydrogen production due to their severe carrier recombination problems.To mitigate this crucial issue,establishing heterojunction is deemed an effective approach.Nonetheless,many of the metal-containing materials that have been used to construct heterojunctions with COFs own a number of drawbacks,including small specific surface area and rare active sites(for inorganic semiconductor materials),wider bandgaps and higher preparation costs(for MOFs).Therefore,it is necessary to choose metal-free materials that are easy to prepare.Red phosphorus(RP),as a semiconductor material without metal components,with suitable bandgap,moderate redox potential,relatively minimal toxicity,is affordable and readily available.Herein,a range of RP/TpPa-1-COF(RP/TP1C)composites have been successfully prepared through solvothermal method.The two-dimensional structure of the two materials causes strong interactions between the materials,and the construction of heterojunctions effectively inhibits the recombination of photogenic charge carriers.As a consequence,the 9%RP/TP1C composite,with the optimal photocatalytic ability,achieves a photocatalytic H2 evolution rate of 6.93 mmol g^(-1) h^(-1),demonstrating a 10.19-fold increase compared to that of bare RP and a 4.08-fold improvement over that of pure TP1C.This article offers a novel and innovative method for the advancement of efficient COF-based photocatalysts.展开更多
Different materials,such as metal sulphides,are often combined with metal‐organic frameworks(MOFs)to develop multi‐functional composites and improve their photocatalytic properties.However,the high interfacial energ...Different materials,such as metal sulphides,are often combined with metal‐organic frameworks(MOFs)to develop multi‐functional composites and improve their photocatalytic properties.However,the high interfacial energy barrier limits the formation and nano‐assembly of the heterogeneous junctions between MOFs and metal sulphides.Herein,the heterostructured Zr‐MOF‐S@CdS are successfully constructed through a sequential synthesis method,in which the mesoporous Zr‐MOF are firstly decorated with thioglycolic acid through pore functionalization,and followed by the S^(2-)anion exchange process resulting in the surface close attached growth of CdS onto Zr‐MOF‐S materials.Due to the presence of molecules linkers,the CdS can be precisely decorated onto Zr‐MOF‐S without aggregation,which can provide more active sites.Moreover,the intimate connections and the suitable band structures between two materials can also facilitate the photogenerated electron‐hole pairs separation.Therefore,the resulting Zr‐MOF‐S@CdS with appropriate ratio exhibits high photocatalytic activity for water reduction,in which the H_(2) evolution rate can reach up to 1861.7μmol·g^(‒1)·h^(‒1),4.5 times higher than pure CdS and 2.3 times higher than of Zr‐MOF/CdS,respectively.Considering the promising future of MOF‐based photocatalysts,this work may provide an avenue for the further design and synthesis MOF‐based composite photocatalysts for efficient H_(2) evolution.展开更多
In this paper,an experimental investigation is conducted to study the mechanical behavior of saturated natural loess,saturated natural filling in ground fissure and their corresponding saturated remoulded soils under ...In this paper,an experimental investigation is conducted to study the mechanical behavior of saturated natural loess,saturated natural filling in ground fissure and their corresponding saturated remoulded soils under three consolidated undrained triaxial stress tests,namely,conventional triaxial compression test(CTC),triaxial compression test(TC)and reduced triaxial compression test(RTC).The test results show that stress-strain relation,i.e.strain-softening or strain-hardening,is remarkably influenced by the structure,void ratio,stress path and confining pressure.Natural structure,high void ratio,TC stress path,RTC stress path and low confining pressures are favorable factors leading to strain-softening.Excess pore pressure during shearing is significantly affected by stress path.The tested soils are different from loose sand on character of strain-softening and are different from common clay on excess pore water pressure behavior.The critical states in p′-q space in CTC,TC and RTC tests almost lie on one line,which indicates that the critical state is independent of the above stress paths.As for remoulded loess or remoulded filling,the critical state line(CSL)and isotropic consolidation line(ICL)in e-log p′space are almost straight,while for natural loess or natural filling,in e-log p′space there is a turning point on the CSL,which is similar to the ICL.展开更多
Owing to the need for regenerant and self-reduction problem,the hydrogen performance of sub-nano-sized trinuclear iron-oxo complexes is still far from satisfied with affordability and practicality.Herein,two binary ph...Owing to the need for regenerant and self-reduction problem,the hydrogen performance of sub-nano-sized trinuclear iron-oxo complexes is still far from satisfied with affordability and practicality.Herein,two binary photocatalytic systems based on trinuclear metal-oxo complexes have been first constructed and experimentally confirmed to be competent for seawater hydrogen evolution(715.4and271.9μmol of hydrogen can be found,respectively,after 48h).Notably,chloride ions act as the hole catcher and move into the gas phase in the stable form of chlorine.Similar to heterogeneous structures,homogeneous systemsnot only enhance the hydrogen performance while ensuring the stability of metal-oxo complexes,but also shorten the consumption of photogenerated carriers by dissolved impurities in the seawater.This new attempt of building pluralistic sub-nanometric systems may offer novel design strategies with noble-metal-free catalysts and low-cost candidates for traditional semiconductor materials in enhancing photocatalytic efficiency and performing chlorine evolution from seawater splitting.展开更多
基金the National Natural Science Foundation of China(Grant No.42207171).
文摘Understanding water dynamics under the effect of climatic conditions is important to improve water sustainability over the medium-and long-term.Clay content can affect soil hydrothermal properties,and hence modify water and heat exchange between soil and atmosphere,e.g.evapotranspiration and infiltration.This work aims to develop a numerical approach to explore the influence of clay content on soil hydrothermal response to the timely climatic conditions in the Lake Chad region,Sahel Region of west-central Africa.The meteorological information at the studied points,i.e.points A and B with a clay content of 8.3%and 25%,during the year 2008 is collected from ERA5-Land hourly data.The numerical results allow for understanding the effect of clay content on the hydrothermal response of the surface soil layer.Specifically,the soil surface temperature under point A is lower than that under point B during the dry season due to the dominant effect of heat conduction.However,the converse tendency is observed during the wet season because of the combined effect of heat conduction and latent heat.The variations of soil volumetric water content are closely related to the timely interaction between the soil and atmosphere,in addition to the hydrothermal properties of soil.Moreover,the outcomes of this work improve the understanding of the heat and water dynamics under the effect of climatic conditions and clay content,and provide further insights into the potential water protection in arid and semi-arid regions in the future.
基金support from the National Natural Science Foundation of China(No.52171080)。
文摘The recognition and monitoring of localized corrosion at the early stage on the inner wall surface of pipes are extremely difficult and simultaneously the reliable approach for recognition and monitoring is missing.Here we report a spatially resolved method to recognize and monitor the localized corrosion in a non-destructive way based on the permeating hydrogen signal generated from localized corrosion itself.A simulative localized corrosion was created on one side surface of the carbon steel specimen where a dot of wet elemental sulfur was introduced to accelerate the corrosion on the local region.While,the potential on the other side surface(the reverse side of the corrosion site)of the specimen was measured using a scanning Kelvin probe.The results show that the permeating hydrogen generated from localized corrosion easily arrives on the reverse side surface of the corrosion site and then causes a huge change in surface potential.The location resolution of potential distribution can be revealed with micron level.Therefore,it is thought that the location of localized corrosion can be recognized by the permeating hydrogen signal distribution on the reverse side surface of the corrosion site since the region of potential decreasing is highly corresponding to the corrosion site.Moreover,the strength of the permeating hydrogen signal is highly related to the corrosion depth and transient corrosion rate of localized corrosion.This means that the localized corrosion development can also be monitored using the permeating hydrogen signal.Therefore,it can be expected that the localized corrosion occurring on the inner wall surface of pipes or equipment can be recognized and monitored successfully on the outer wall surface in a non-destructive way once the permeating hydrogen is present during the localized corrosion proceeding.
基金supported by the National Natural Science Foundation of China(Nos.52071171,52202248,22101105)Liaoning Province Centrally Guided Local Science and Technology Development Fund Program(2024JH6/100700010,2024JH6/100700011)+8 种基金Open Project of State Key Laboratory of Inorganic Synthesis and Preparative Chemistry(2024-35)Open Research Fund of Guangdong Advanced Carbon Materials Co.,Ltd.(Kargen-2024B1001),and Key Research Project of Department of Education of Liaoning Province(LJKZZ20220015)T.M.acknowledged the Australian Research Council(ARC)through Future Fellowship(FT210100298)Discovery Project(DP220100603)Linkage Project(LP210200504,LP220100088,LP230200897)Industrial Transformation Research Hub(IH240100009)schemesthe Australian Government through the Cooperative Research Centres Projects(CRCPXIII000077)the Australian Renewable Energy Agency(ARENA)as part of ARENA's Transformative Research Accelerating Commercialisation Program(TM021)European Commission's Australia-Spain Network for Innovation and Research Excellence(AuSpire)。
文摘Covalent organic frameworks(COFs)are newly developed crystalline substances that are garnering growing interest because of their ultrahigh porosity,crystalline nature,and easy-modified architecture,showing promise in the field of photocatalysis.However,it is difficult for pure COFs materials to achieve excellent photocatalytic hydrogen production due to their severe carrier recombination problems.To mitigate this crucial issue,establishing heterojunction is deemed an effective approach.Nonetheless,many of the metal-containing materials that have been used to construct heterojunctions with COFs own a number of drawbacks,including small specific surface area and rare active sites(for inorganic semiconductor materials),wider bandgaps and higher preparation costs(for MOFs).Therefore,it is necessary to choose metal-free materials that are easy to prepare.Red phosphorus(RP),as a semiconductor material without metal components,with suitable bandgap,moderate redox potential,relatively minimal toxicity,is affordable and readily available.Herein,a range of RP/TpPa-1-COF(RP/TP1C)composites have been successfully prepared through solvothermal method.The two-dimensional structure of the two materials causes strong interactions between the materials,and the construction of heterojunctions effectively inhibits the recombination of photogenic charge carriers.As a consequence,the 9%RP/TP1C composite,with the optimal photocatalytic ability,achieves a photocatalytic H2 evolution rate of 6.93 mmol g^(-1) h^(-1),demonstrating a 10.19-fold increase compared to that of bare RP and a 4.08-fold improvement over that of pure TP1C.This article offers a novel and innovative method for the advancement of efficient COF-based photocatalysts.
文摘Different materials,such as metal sulphides,are often combined with metal‐organic frameworks(MOFs)to develop multi‐functional composites and improve their photocatalytic properties.However,the high interfacial energy barrier limits the formation and nano‐assembly of the heterogeneous junctions between MOFs and metal sulphides.Herein,the heterostructured Zr‐MOF‐S@CdS are successfully constructed through a sequential synthesis method,in which the mesoporous Zr‐MOF are firstly decorated with thioglycolic acid through pore functionalization,and followed by the S^(2-)anion exchange process resulting in the surface close attached growth of CdS onto Zr‐MOF‐S materials.Due to the presence of molecules linkers,the CdS can be precisely decorated onto Zr‐MOF‐S without aggregation,which can provide more active sites.Moreover,the intimate connections and the suitable band structures between two materials can also facilitate the photogenerated electron‐hole pairs separation.Therefore,the resulting Zr‐MOF‐S@CdS with appropriate ratio exhibits high photocatalytic activity for water reduction,in which the H_(2) evolution rate can reach up to 1861.7μmol·g^(‒1)·h^(‒1),4.5 times higher than pure CdS and 2.3 times higher than of Zr‐MOF/CdS,respectively.Considering the promising future of MOF‐based photocatalysts,this work may provide an avenue for the further design and synthesis MOF‐based composite photocatalysts for efficient H_(2) evolution.
基金supported by China National Funds for Distinguished Young Scientists(No.51025932)the National Natural Science Foundation of China(Grant Nos.10922158 and 40534021the Land and Natural Resources of China(No.1212010914013).
文摘In this paper,an experimental investigation is conducted to study the mechanical behavior of saturated natural loess,saturated natural filling in ground fissure and their corresponding saturated remoulded soils under three consolidated undrained triaxial stress tests,namely,conventional triaxial compression test(CTC),triaxial compression test(TC)and reduced triaxial compression test(RTC).The test results show that stress-strain relation,i.e.strain-softening or strain-hardening,is remarkably influenced by the structure,void ratio,stress path and confining pressure.Natural structure,high void ratio,TC stress path,RTC stress path and low confining pressures are favorable factors leading to strain-softening.Excess pore pressure during shearing is significantly affected by stress path.The tested soils are different from loose sand on character of strain-softening and are different from common clay on excess pore water pressure behavior.The critical states in p′-q space in CTC,TC and RTC tests almost lie on one line,which indicates that the critical state is independent of the above stress paths.As for remoulded loess or remoulded filling,the critical state line(CSL)and isotropic consolidation line(ICL)in e-log p′space are almost straight,while for natural loess or natural filling,in e-log p′space there is a turning point on the CSL,which is similar to the ICL.
基金This work was supported by the National Natural Sci-ence Foundation of China(No.52071171)Liaoning Revitalization Talents Program-Pan Deng Scholars(XLYC1802005)+6 种基金Liaoning BaiQianWan Talents Program(LNBQW2018B0048)Natural Science Fund of Liaoning Province for Excellent Young Scholars(2019-YQ-04)Key ProjectofScientificResearchoftheEducationDepartment of Liaoning Province(LZD201902)Shenyang Science and Technology Project(21-108-9-04)Australian Research Council(ARC)through Future Fellowship(FT210100298)Discovery Project(DP220100603)Linkage Project(LP210200504)schemes,CSIRO Energy Centre and Kick-Start Project.
文摘Owing to the need for regenerant and self-reduction problem,the hydrogen performance of sub-nano-sized trinuclear iron-oxo complexes is still far from satisfied with affordability and practicality.Herein,two binary photocatalytic systems based on trinuclear metal-oxo complexes have been first constructed and experimentally confirmed to be competent for seawater hydrogen evolution(715.4and271.9μmol of hydrogen can be found,respectively,after 48h).Notably,chloride ions act as the hole catcher and move into the gas phase in the stable form of chlorine.Similar to heterogeneous structures,homogeneous systemsnot only enhance the hydrogen performance while ensuring the stability of metal-oxo complexes,but also shorten the consumption of photogenerated carriers by dissolved impurities in the seawater.This new attempt of building pluralistic sub-nanometric systems may offer novel design strategies with noble-metal-free catalysts and low-cost candidates for traditional semiconductor materials in enhancing photocatalytic efficiency and performing chlorine evolution from seawater splitting.
