In persulfate-based advanced oxidation process(PS-AOPs),fixing nanosized metal oxide on processable substrates is highly desirable to avoid the aggregation and loss of nanocatalysts during the practical application.Ho...In persulfate-based advanced oxidation process(PS-AOPs),fixing nanosized metal oxide on processable substrates is highly desirable to avoid the aggregation and loss of nanocatalysts during the practical application.However,it is still challenging to develop a versatile strategy for the deposition of metal oxide nanocatalysts on various substrates with different physicochemical properties.Herein,polyphenols are utilized as a“molecular glue”and reductant to mediate the interfacial deposition of MnO_(2) nanocatalysts on different substrates.MnO_(2) nanocatalysts were in-situ grown on macroscope mineral substrates(e.g.,airstone)via an interfacial redox strategy between tannic acid(TA)and oxidized KMnO4,and then employed as a fixed catalyst of peroxymonosulfate(PMS)activation for treating pharmaceutical and personal care products(PPCPs)in water.The fixed MnO_(2) exhibited superior catalytic performance toward different PPCPS via a singlet oxygen(^(1)O_(2))-dominated nonradical oxidation pathway.PPCPs in the secondary effluent of wastewater treatment plants could be effectively removed by a fixed-bed column of the fixed MnO_(2) with long term stability.Redox cycle of Mn^(4+)/Mn^(3+)and surface hydroxyl group of the fixed MnO_(2) was proved to be responsible for the activation of PMS.This work provides a new avenue for developing fixed metal oxides for sustainable water treatment.展开更多
Shifts in tree species and their mycorrhizal associations driven by global change play key roles in biogeochemical cycles. In this paper, we proposed a framework of the mycorrhizal-associated nutrient economy(MANE), a...Shifts in tree species and their mycorrhizal associations driven by global change play key roles in biogeochemical cycles. In this paper, we proposed a framework of the mycorrhizal-associated nutrient economy(MANE), and tested it using nutrient addition experiments conducted in two tropical rainforests. We selected two tropical rainforests dominated by arbuscular mycorrhizal(AM) and ectomycorrhizal(ECM) trees, and established eighteen20 m×20 m plots in each rainforest. Six nitrogen(N) and phosphorus(P) addition treatments were randomly distributed in each rainforest with three replicates. We examined the differences in soil carbon(C) and nutrient cycling, plant and litter productivity between the two rainforests and their responses to 10-year inorganic N and P additions. We also quantified the P pools of plants, roots, litter, soil and microbes in the two rainforests. Overall,distinct MANE frameworks were applicable for tropical rainforests, in which soil C, N and P were cycled primarily in an inorganic form in the AM-dominated rainforest, whereas they were cycled in an organic form in the ECMdominated rainforest. Notably, the effects of mycorrhizal types on soil P cycling were stronger than those on C and N cycling. The intensified N and P deposition benefited the growth of AM-dominated rainforests instead of ECMdominated rainforests. Our findings underpin the key role of mycorrhizal types in regulating biogeochemical processes, and have important implications for predicting the ecological consequences of global changes.展开更多
Hierarchically porous anatase Ti02 microspheres composited with carbonaceous species （TCS） have been successfully fabricated by a one-step template-free solvothermal method, combined with subsequent low temperature ...Hierarchically porous anatase Ti02 microspheres composited with carbonaceous species （TCS） have been successfully fabricated by a one-step template-free solvothermal method, combined with subsequent low temperature dried process. In this configuration, the TCS microspheres are constructed by the intercon- nected porous nanosheets, which are further assembled with abundant nanoparticles and carbonaceous species. Such composite microspheres possess a large specific surface area of 337 m2 g-l, uniform mesopores of 3.37 nm and high total pore volumes of 0.275 cm3 g-1. The materials exhibit the enhanced photocatalytic properties and stability for degradation of rhodamine B （RhB） under visible-light irradiation. The enhanced photocatalytic degradation performance may be ascribed to their abundant porous structure, large specific surface area and the unique assist-function of the carbonaceous species.展开更多
In the present work,a stable two-dimensional(2D)P_(2)Si monolayer was predicted.The monolayer is semimetallic/metallic under the PBE/HSE06 functional and is mechanically isotropic.The stability of the P_(2)Si monolaye...In the present work,a stable two-dimensional(2D)P_(2)Si monolayer was predicted.The monolayer is semimetallic/metallic under the PBE/HSE06 functional and is mechanically isotropic.The stability of the P_(2)Si monolayer has been proved via cohesive energy,mechanical criteria,molecular dynamics simulation,and phonon dispersion respectively,and the monolayer possesses high carrier mobility which is three times that of Mo S_(2).On the other hand,the catalytic performance of the P_(2)Si monolayer modified with a single transition metals(M=Sc-Cu)atom for the electrochemical reduction of CO_(2)was investigated,and the monolayer can catalyze CO_(2)with three constraints:stable molecular dynamics,high migration potential of metal atoms,and suitable band gap for electrocatalyst after metal doping exhibiting excellent catalytic stabilization activity and CRR selectivity.In addition,the reduction product of V@P_(2)Si is HCOOH with an overpotential as low as 0.75 V,and the most suitable reaction path is^(*)CO_(2)→^(*)CHOO→O^(*)CHOH→^(*)+HCOOH with the final reduction product HCOOH obtained.As a whole,the above results endow the P_(2)Si monolayer to be a good 2D material holding great promises for applications in nanoelectronics and CO_(2)reduction catalysts.展开更多
A novel plastic/multi-walled carbon nanotube（MWNTs）-nickel（Ni）-platinum（Pt） electrode（PMNP） is prepared by chemical-reducing Pt onto the surface of Ni film covered plastic/MWNTs（PM） substrate. The MWNTs are ...A novel plastic/multi-walled carbon nanotube（MWNTs）-nickel（Ni）-platinum（Pt） electrode（PMNP） is prepared by chemical-reducing Pt onto the surface of Ni film covered plastic/MWNTs（PM） substrate. The MWNTs are adhered by a piece of commercial double faced adhesive tape on the surface of plastic paper and the Ni film is prepared by a simple electrodeposition method. The morphology and phase structure of the PMNP electrode are characterized by scanning electron microscopy,transmission electron microscope and X-ray diffractometer. The catalytic activity of the PMNP electrode for Na BH4 electrooxidation is investigated by means of cyclic voltammetry and chronoamperometry. The catalyst combines tightly with the plastic paper and exhibits a good stability. MWNTs serve as both conductive material and hydrogen storage material and the Ni film and Pt are employed as electrochemical catalysts. The PMNP electrode exhibits a high electrocatalytic performance and the oxidation current density reaches to 10.76 A/（mg·cm） in 0.1 mol/dm3 Na BH4at0 V,which is much higher than those in the previous reports. The using of waste plastic reduces the discarding of white pollution and consumption of metal resources.展开更多
We predicted two stable two-dimensional materials of carbon and bismuth elements,namely BiC and Bi_(2)C monolayers.The stabilities of two monolayers were examined by cohesive energy,Born criteria,first-principle MD si...We predicted two stable two-dimensional materials of carbon and bismuth elements,namely BiC and Bi_(2)C monolayers.The stabilities of two monolayers were examined by cohesive energy,Born criteria,first-principle MD simulations and phonon spectra,respectively.By including the spin-orbit coupling effects,the BiC monolayer is a metal and the Bi_(2)C monolayer possesses a narrow direct(indirect)band gap of 0.403(0.126)eV under the HSE06(GGA-PBE)functional.For the adsorption of CO_(2)molecules,the BiC and Bi_(2)C monolayers have three stable adsorption sites C2,T3 and T4 with the adsorption energies as-0.57,-0.51 and-0.81 eV,and the activation ability on the adsorption as T4>T3>C2.These consequences make the BiC and Bi_(2)C monolayers to be promising adsorbents to capture CO_(2)gas,the Bi_(2)C monolayer to be well photovoltaics and optoelectronics material,and the BiC monolayer to be ideal battery and electronics materials,respectively.展开更多
Warming has been consistently observed to reduce soil carbon(C)storage by accelerating the decomposition of soil organic matter.While different soil C fraction may respond differentially to warming,microbial necromass...Warming has been consistently observed to reduce soil carbon(C)storage by accelerating the decomposition of soil organic matter.While different soil C fraction may respond differentially to warming,microbial necromass has been considered as an important contributor to the persistent soil C pool.However,the mechanisms by which warming regulates microbial necromass formation and its potential contribution to new soil organic carbon(SOC)fractions remain poorly understood.In this study,we examined the effects of elevated temperature on newly formed amino sugar C(an indicator of fungal and bacterial-derived microbial necromass C)and its allocation in particulate organic matter(POM)and mineral-associated organic matter(MAOM)fractions in alpine soils of Southwest China,based on a 37-day incubation experiment at 15℃ and 25℃ by adding ^(13)C labeled glucose and oxalic acid.The results showed that warming significantly reduced the formation of new SOC by lowering the incorporation of new C into both POM and MAOM fractions.Glucose addition was more effective than oxalic acid in promoting new SOC formation,regardless of temperature.Warming also significantly decreased the new microbial necromass in both soil fractions with more bacterial necromass associated with mineral particles,which was primarily attributed to the higher abundance of bacterial community.In addition,glucose addition significantly promoted contribution of the fungal necromass to newly formed SOC.Overall,this study reveals that warming significantly alters the allocation of newly formed SOC and microbial necromass,highlighting the dfferential microbial responses in soil C sequestration.These findings have important implications for predicting and managing soil C stocks in forest ecosystems under climate change.展开更多
Alpine regions sequester large vulnerable and unprotected soil organic carbon(SOC),determining its extreme sensitivity to global change and pivotal role in the carbon cycle.However,there is ongoing debate regarding ho...Alpine regions sequester large vulnerable and unprotected soil organic carbon(SOC),determining its extreme sensitivity to global change and pivotal role in the carbon cycle.However,there is ongoing debate regarding how SOC storage and its stabilizing mechanism vary along altitudinal gradients.Here,we examined the SOC contents of soil aggregate and density fractions,and their interactions with climate,biology,and soil properties along elevation(2100-3900 m)of western Yulong Mountain in Southwest China.Results showed that SOC contents in bulk soils and heavy fractions significantly increased with elevated altitudes,whereas no changes in aggregates.The increasing Fe/Al oxides with altitudes might be responsible for such significant variations.While soil C-enzyme activities had strong effects on increasing SOC in macroaggregates(>250μm),aggregate stability(indicated by mean weight diameter and soil erodibility)mainly reduced SOC in microaggregates,silt and clay(<250μm).The structural equation models further showed that 57%-91%of variations in SOC contents could be explained by environmental variables,with the Fe/Al oxides showing the strongest positive associations with SOC contents in bulk soils,light and heavy fractions.Taken together,our results emphasized positive impacts of mineral protection on the SOC stabilization at high altitudes.This not only offers novel insights into predicting soil C stability in alpine regions but also provides practical significance for soil C pool management across various altitudes.展开更多
Aims Terrestrial net primary production(NPP),the balance of gross primary production(GPP)and autotrophic respiration(AR),is a critical measure of carbon sequestration capacity for the Earth’s land surface.The aim of ...Aims Terrestrial net primary production(NPP),the balance of gross primary production(GPP)and autotrophic respiration(AR),is a critical measure of carbon sequestration capacity for the Earth’s land surface.The aim of this study was to understand the spatio-temporal variability of NPP associated with GPP and AR in the Yangtze River Basin(YRB),China,from 2000 to 2009 during which the basin warmed significantly.Methods We first derived AR and carbon-use efficiency(CUE)from the improved Moderate Resolution Imaging Spectroradiometer GPP/NPP products(MOD17)and then conducted spatial analysis to quantify how NPP relates to GPP,AR and their relationship with key observed climate variables(temperature,precipitation and sunshine percentage)in the YRB during 2000–2009.Important Findings The spatial pattern of NPP in the YRB was predominantly determined by GPP and further modified by AR.Higher GPP and relatively low AR made the southern Jinshajiang sub-basin the most productive area in NPP in the YRB.A large portion of the YRB experienced a warmer and drier climate trend in the growing season during 2000–2009.In the upper reaches of the basin,possessing a relatively low temperature base,increases in temperature led to greater increases in GPP than those in AR,resulting in greater increased NPP.However,in the middle and lower reaches of the basin where the base temperature is relatively high,increases in temperature led to greater increases in AR than those in GPP,leading to decreases in NPP.Overall,86.7%of the vegetated area showed a consistent GPP and NPP trend through time with 71.3%of the vegetated area having a positive trend both in GPP and NPP,and the remaining 13.3%of vegetated areas showed an opposite trend in GPP and NPP,with positive GPP and negative NPP trajectories dominating(10.1%of vegetated area)the trend.Although climate warming generally had positive effects on vegetation growth in most areas of the basin,areas with increased NPP(74.5%)were less extensive than those with increased GPP(81.4%)due to the wider increase in AR(82.2%).During the study period,increases in AR offset 62%of the total increased GPP,leading to a substantial decline of CUE,particularly in the warmer lower altitude regions in the southeast.Our work reveals the diverse responses of NPP associated with GPP and AR as the climate warms and generally suggests that NPP in the middle and lower sub-basins in the YRB is more sensitive to future climate warming.These findings enhance our understanding of terrestrial ecosystem carbon dynamics in response to global warming and provide a scientific basis for managing ecosystem productivity in the YRB,China.展开更多
The clear differences between the atmosphere of Mars and the Earth coupled with the lack of a domestic research basis were significant challenges for the aerodynamic prediction and verification of Tianwen-1.In additio...The clear differences between the atmosphere of Mars and the Earth coupled with the lack of a domestic research basis were significant challenges for the aerodynamic prediction and verification of Tianwen-1.In addition,the Mars entry,descent,and landing(EDL)mission led to specific requirements for the accuracy of the aerodynamic deceleration performance,stability,aerothermal heating,and various complex aerodynamic coupling problems of the entry module.This study analyzes the key and difficult aerodynamic and aerothermodynamic problems related to the Mars EDL process.Then,the study process and results of the design and optimization of the entry module configuration are presented along with the calculations and experiments used to obtain the aerodynamic and aerothermodynamic characteristics in the Martian atmosphere.In addition,the simulation and verification of the low-frequency free oscillation characteristics under a large separation flow are described,and some special aerodynamic coupling problems such as the aeroelastic buffeting response of the trim tab are discussed.Finally,the atmospheric parameters and aerodynamic characteristics obtained from the flight data of the Tianwen-1 entry module are compared with the design data.The data obtained from the aerodynamic design,analysis,and verification of the Tianwen-1 entry module all meet the engineering requirements.In particular,the flight data results for the atmospheric parameters,trim angles of attack,and trim axial forces are within the envelopes of the prediction deviation zones.展开更多
Land use management affects plant carbon(C)supply and soil environments and hence alters soil nitrogen(N)dynamics,with consequent feedbacks to terrestrial ecosystem productivity.The objective of this study was to bett...Land use management affects plant carbon(C)supply and soil environments and hence alters soil nitrogen(N)dynamics,with consequent feedbacks to terrestrial ecosystem productivity.The objective of this study was to better identify mechanisms by which land-use management(clipping and shading)regulates soil N in a tallgrass prairie,OK,USA.Methods We conducted 1-year clipping and shading experiment to investigate the effects of changes in land-use management(soil microclimates,plant C substrate supply and microbial activity)on soil inorganic N(NH_(4)^(+)-N and NO_(3)^(-)-N),net N mineralization and nitrification in a tallgrass prairie.Important Findings Land-use management through clipping and/or shading significantly increased annual mean inorganic N,possibly due to lowered plant N uptake and decreased microbial N immobilization into biomass growth.Shading significantly increased annual mean mineralization rates(P<0.05).Clipping slightly decreased annual mean N nitrification rates whereas shading significantly increased annual mean N nitrification rates.Soil microclimate significantly explained 36%of the variation in NO_(3)^(-)-N concentrations(P=0.004).However,soil respiration,a predictor of plant C substrate supply and microbial activity,was negatively correlated with NH_(4)^(+)-N concentrations(P=0.0009),net N mineralization(P=0.0037)and nitrification rates(P=0.0028)across treatments.Our results suggest that change in C substrate supply andmicrobial activity under clipping and/or shading is a critical control on NH_(4)^(+)-N,net N mineralization and nitrification rates,whereas clipping and shading-induced soil microclimate change can be important for NO_(3)^(-)-N variation in the tallgrass prairie.展开更多
As an excellent room temperature sensing material,polyaniline(PANI)needs to be further investigated in the field of high sensitivity and sustainable gas sensors due to its long recovery time and difficulty to complete...As an excellent room temperature sensing material,polyaniline(PANI)needs to be further investigated in the field of high sensitivity and sustainable gas sensors due to its long recovery time and difficulty to complete recovery.The ZnO/PANI film with p-n heterogeneous energy levels have successfully prepared by spraying Zno nanorod synthesized by hydrothermal method on the PANI film rapidly synthesized at the gas-liquid interface.The presence of p-n heterogeneous energy levels enables the ZnO/PANI film to detect 0.1-100 ppm(1 ppm=10^(-6))NH_(3)at room temperature with the response value to 100 ppm NH_(3)doubled(12.96)and the recovery time shortened to 1/5(31.2s).The ability of high response and fast recovery makes the ZnO/PANI filmto be able to detect NH_(3)at room temperature continuously.It provides a new idea for PANI to prepare sustainable room temperature sensor and promotes the development of room temperature sensor in public safety.展开更多
In the article titled“Thermal Environment and Aeroheating Mechanism of Protuberances on Mars Entry Capsule”[1],there was an error in the author name details.The first name and surname of all authors were transposed....In the article titled“Thermal Environment and Aeroheating Mechanism of Protuberances on Mars Entry Capsule”[1],there was an error in the author name details.The first name and surname of all authors were transposed.The correct author names are shown below,and they are corrected in the author list.展开更多
Soil dissolved organic matter (DOM) is vital in terrestrial ecosystem carbon (C) cycling;however,the regulatory effects of forest types and elevations on soil DOM dynamics in mountain ecosystems remain incompletely un...Soil dissolved organic matter (DOM) is vital in terrestrial ecosystem carbon (C) cycling;however,the regulatory effects of forest types and elevations on soil DOM dynamics in mountain ecosystems remain incompletely understood.Here,we investigated DOM content,spectroscopic characteristics,molecular traits and their potential drivers along an elevational gradient (2600-3500 m) in the Hengduan Mountains.Our results showed that soil dissolved organic C (DOC) content was higher in broad-leaf forest soil (at 2900 m and 3500 m) than in coniferous forest soil (at 2600 m and 3200 m) irrespective of elevation,with a greater amount in wet season than in dry season.Humification index (HIX) trends aligned with the DOC content,while the aromaticity index (AI) showed an inverse relationship.These patterns were linked to the quality of litter carbon sources.Molecular-level analysis of DOM suggested that lignins/CRAM-like structure compounds and tannins predominated in soil DOM,indicating that the molecular composition of soil DOM was typical of plant-derived sources in our study region.Additionally,the relative abundance of lignin compounds decreased gradually with increasing elevation during the dry season.We detected that soil properties (especially,NH_(4)^(+)-N content) predominantly mediated DOM dynamics in dry season,whereas litter traits (i.e.,leaf-DOC content) were the key factors across elevations in wet season.Overall,our results revealed litter traits and soil properties predominantly regulated soil DOM mechanism along elevational gradient,indicating that soil DOM dynamics associated with tree species in alpine mountain ecosystems may differentially influence soil C sequestration under future climate change scenarios.展开更多
基金financially supported by the National Key Research and Development Program(No.2022YFE0100400)National Natural Science Foundation of China(No.21701130)+2 种基金Key Basic Research Program of Science and Technology Commission of Shanghai Municipality(No.20JC1415300)State Key Laboratory of Transducer Technology of China(No.SKT2207)Key Research and Development Program of Shaanxi(No.2021GY-225)。
文摘In persulfate-based advanced oxidation process(PS-AOPs),fixing nanosized metal oxide on processable substrates is highly desirable to avoid the aggregation and loss of nanocatalysts during the practical application.However,it is still challenging to develop a versatile strategy for the deposition of metal oxide nanocatalysts on various substrates with different physicochemical properties.Herein,polyphenols are utilized as a“molecular glue”and reductant to mediate the interfacial deposition of MnO_(2) nanocatalysts on different substrates.MnO_(2) nanocatalysts were in-situ grown on macroscope mineral substrates(e.g.,airstone)via an interfacial redox strategy between tannic acid(TA)and oxidized KMnO4,and then employed as a fixed catalyst of peroxymonosulfate(PMS)activation for treating pharmaceutical and personal care products(PPCPs)in water.The fixed MnO_(2) exhibited superior catalytic performance toward different PPCPS via a singlet oxygen(^(1)O_(2))-dominated nonradical oxidation pathway.PPCPs in the secondary effluent of wastewater treatment plants could be effectively removed by a fixed-bed column of the fixed MnO_(2) with long term stability.Redox cycle of Mn^(4+)/Mn^(3+)and surface hydroxyl group of the fixed MnO_(2) was proved to be responsible for the activation of PMS.This work provides a new avenue for developing fixed metal oxides for sustainable water treatment.
基金supported by the National Natural Science Foundation of China(No.31988102)National Key Research and Development Program of China(No.2017YFC0503906)。
文摘Shifts in tree species and their mycorrhizal associations driven by global change play key roles in biogeochemical cycles. In this paper, we proposed a framework of the mycorrhizal-associated nutrient economy(MANE), and tested it using nutrient addition experiments conducted in two tropical rainforests. We selected two tropical rainforests dominated by arbuscular mycorrhizal(AM) and ectomycorrhizal(ECM) trees, and established eighteen20 m×20 m plots in each rainforest. Six nitrogen(N) and phosphorus(P) addition treatments were randomly distributed in each rainforest with three replicates. We examined the differences in soil carbon(C) and nutrient cycling, plant and litter productivity between the two rainforests and their responses to 10-year inorganic N and P additions. We also quantified the P pools of plants, roots, litter, soil and microbes in the two rainforests. Overall,distinct MANE frameworks were applicable for tropical rainforests, in which soil C, N and P were cycled primarily in an inorganic form in the AM-dominated rainforest, whereas they were cycled in an organic form in the ECMdominated rainforest. Notably, the effects of mycorrhizal types on soil P cycling were stronger than those on C and N cycling. The intensified N and P deposition benefited the growth of AM-dominated rainforests instead of ECMdominated rainforests. Our findings underpin the key role of mycorrhizal types in regulating biogeochemical processes, and have important implications for predicting the ecological consequences of global changes.
基金financially supported by the National Natural Science Foundation of China(Nos.61271126,21547012 and 21305033)the Program for Innovative Research Team in University(No.IRT-1237)+2 种基金the Program for Science and Technology Project of Heilongjiang province(Nos.B201414 and B2015008)the Heilongjiang Educational Department(No.2013TD002,2011CJHB006,12531506)the Youth Foundation of Harbin(No.2015QQQXJ047)
文摘Hierarchically porous anatase Ti02 microspheres composited with carbonaceous species （TCS） have been successfully fabricated by a one-step template-free solvothermal method, combined with subsequent low temperature dried process. In this configuration, the TCS microspheres are constructed by the intercon- nected porous nanosheets, which are further assembled with abundant nanoparticles and carbonaceous species. Such composite microspheres possess a large specific surface area of 337 m2 g-l, uniform mesopores of 3.37 nm and high total pore volumes of 0.275 cm3 g-1. The materials exhibit the enhanced photocatalytic properties and stability for degradation of rhodamine B （RhB） under visible-light irradiation. The enhanced photocatalytic degradation performance may be ascribed to their abundant porous structure, large specific surface area and the unique assist-function of the carbonaceous species.
基金funded by the Natural Science Foundation of China(Nos.21603109,11304128)the Henan Joint Fund of the National Natural Science Foundation of China(No.U1404216)+1 种基金the Science and Technology Program of Henan Department of Science and Technology,China(No.182102310609)the Construct Program of Applied Characteristic Discipline in Hunan University of Science and Engineering(Mathematics,Education and Electronic Science and Technology)。
文摘In the present work,a stable two-dimensional(2D)P_(2)Si monolayer was predicted.The monolayer is semimetallic/metallic under the PBE/HSE06 functional and is mechanically isotropic.The stability of the P_(2)Si monolayer has been proved via cohesive energy,mechanical criteria,molecular dynamics simulation,and phonon dispersion respectively,and the monolayer possesses high carrier mobility which is three times that of Mo S_(2).On the other hand,the catalytic performance of the P_(2)Si monolayer modified with a single transition metals(M=Sc-Cu)atom for the electrochemical reduction of CO_(2)was investigated,and the monolayer can catalyze CO_(2)with three constraints:stable molecular dynamics,high migration potential of metal atoms,and suitable band gap for electrocatalyst after metal doping exhibiting excellent catalytic stabilization activity and CRR selectivity.In addition,the reduction product of V@P_(2)Si is HCOOH with an overpotential as low as 0.75 V,and the most suitable reaction path is^(*)CO_(2)→^(*)CHOO→O^(*)CHOH→^(*)+HCOOH with the final reduction product HCOOH obtained.As a whole,the above results endow the P_(2)Si monolayer to be a good 2D material holding great promises for applications in nanoelectronics and CO_(2)reduction catalysts.
基金supported by the Fundamental Research Funds for the Central Universities (HEUCF201403018)the Heilongjiang Postdoctoral Fund (LBHZ13059)+1 种基金the China Postdoctoral Science Foundation (2014M561332)the National Natural Science Foundation of China (21403044)
文摘A novel plastic/multi-walled carbon nanotube（MWNTs）-nickel（Ni）-platinum（Pt） electrode（PMNP） is prepared by chemical-reducing Pt onto the surface of Ni film covered plastic/MWNTs（PM） substrate. The MWNTs are adhered by a piece of commercial double faced adhesive tape on the surface of plastic paper and the Ni film is prepared by a simple electrodeposition method. The morphology and phase structure of the PMNP electrode are characterized by scanning electron microscopy,transmission electron microscope and X-ray diffractometer. The catalytic activity of the PMNP electrode for Na BH4 electrooxidation is investigated by means of cyclic voltammetry and chronoamperometry. The catalyst combines tightly with the plastic paper and exhibits a good stability. MWNTs serve as both conductive material and hydrogen storage material and the Ni film and Pt are employed as electrochemical catalysts. The PMNP electrode exhibits a high electrocatalytic performance and the oxidation current density reaches to 10.76 A/（mg·cm） in 0.1 mol/dm3 Na BH4at0 V,which is much higher than those in the previous reports. The using of waste plastic reduces the discarding of white pollution and consumption of metal resources.
基金funded by the Natural Science Foundation of China(Nos.21603109,11304128)the Henan Joint Fund of the National Natural Science Foundation of China(No.U1404216)+1 种基金the Science and Technology Program of Henan Department of Science and Technology,China(No.182102310609)the Construct Program of Applied Characteristic Discipline in Hunan University of Science and Engineering(Mathematics,Education and Electronic Science and Technology).
文摘We predicted two stable two-dimensional materials of carbon and bismuth elements,namely BiC and Bi_(2)C monolayers.The stabilities of two monolayers were examined by cohesive energy,Born criteria,first-principle MD simulations and phonon spectra,respectively.By including the spin-orbit coupling effects,the BiC monolayer is a metal and the Bi_(2)C monolayer possesses a narrow direct(indirect)band gap of 0.403(0.126)eV under the HSE06(GGA-PBE)functional.For the adsorption of CO_(2)molecules,the BiC and Bi_(2)C monolayers have three stable adsorption sites C2,T3 and T4 with the adsorption energies as-0.57,-0.51 and-0.81 eV,and the activation ability on the adsorption as T4>T3>C2.These consequences make the BiC and Bi_(2)C monolayers to be promising adsorbents to capture CO_(2)gas,the Bi_(2)C monolayer to be well photovoltaics and optoelectronics material,and the BiC monolayer to be ideal battery and electronics materials,respectively.
基金supported by the National Natural Science Foundation of China(32130069)Yunnan Fundamental Research Projects(202401AU070231)the Scientific Research Fund of Education Department in Yunnan Province(2024J0001).
文摘Warming has been consistently observed to reduce soil carbon(C)storage by accelerating the decomposition of soil organic matter.While different soil C fraction may respond differentially to warming,microbial necromass has been considered as an important contributor to the persistent soil C pool.However,the mechanisms by which warming regulates microbial necromass formation and its potential contribution to new soil organic carbon(SOC)fractions remain poorly understood.In this study,we examined the effects of elevated temperature on newly formed amino sugar C(an indicator of fungal and bacterial-derived microbial necromass C)and its allocation in particulate organic matter(POM)and mineral-associated organic matter(MAOM)fractions in alpine soils of Southwest China,based on a 37-day incubation experiment at 15℃ and 25℃ by adding ^(13)C labeled glucose and oxalic acid.The results showed that warming significantly reduced the formation of new SOC by lowering the incorporation of new C into both POM and MAOM fractions.Glucose addition was more effective than oxalic acid in promoting new SOC formation,regardless of temperature.Warming also significantly decreased the new microbial necromass in both soil fractions with more bacterial necromass associated with mineral particles,which was primarily attributed to the higher abundance of bacterial community.In addition,glucose addition significantly promoted contribution of the fungal necromass to newly formed SOC.Overall,this study reveals that warming significantly alters the allocation of newly formed SOC and microbial necromass,highlighting the dfferential microbial responses in soil C sequestration.These findings have important implications for predicting and managing soil C stocks in forest ecosystems under climate change.
基金supported by the National Natural Science Foundation of China(32130069)the"Strategic Priority Research Program A of the Chinese Academy of Sciences"(XDA26010102)the Scientific Research Fund teacher project of Education Department of Yunnan Province(2023J0002).
文摘Alpine regions sequester large vulnerable and unprotected soil organic carbon(SOC),determining its extreme sensitivity to global change and pivotal role in the carbon cycle.However,there is ongoing debate regarding how SOC storage and its stabilizing mechanism vary along altitudinal gradients.Here,we examined the SOC contents of soil aggregate and density fractions,and their interactions with climate,biology,and soil properties along elevation(2100-3900 m)of western Yulong Mountain in Southwest China.Results showed that SOC contents in bulk soils and heavy fractions significantly increased with elevated altitudes,whereas no changes in aggregates.The increasing Fe/Al oxides with altitudes might be responsible for such significant variations.While soil C-enzyme activities had strong effects on increasing SOC in macroaggregates(>250μm),aggregate stability(indicated by mean weight diameter and soil erodibility)mainly reduced SOC in microaggregates,silt and clay(<250μm).The structural equation models further showed that 57%-91%of variations in SOC contents could be explained by environmental variables,with the Fe/Al oxides showing the strongest positive associations with SOC contents in bulk soils,light and heavy fractions.Taken together,our results emphasized positive impacts of mineral protection on the SOC stabilization at high altitudes.This not only offers novel insights into predicting soil C stability in alpine regions but also provides practical significance for soil C pool management across various altitudes.
基金The National Natural Science Foundation of China(31130010)The Chinese Academy of Sciences(XDA05060500).
文摘Aims Terrestrial net primary production(NPP),the balance of gross primary production(GPP)and autotrophic respiration(AR),is a critical measure of carbon sequestration capacity for the Earth’s land surface.The aim of this study was to understand the spatio-temporal variability of NPP associated with GPP and AR in the Yangtze River Basin(YRB),China,from 2000 to 2009 during which the basin warmed significantly.Methods We first derived AR and carbon-use efficiency(CUE)from the improved Moderate Resolution Imaging Spectroradiometer GPP/NPP products(MOD17)and then conducted spatial analysis to quantify how NPP relates to GPP,AR and their relationship with key observed climate variables(temperature,precipitation and sunshine percentage)in the YRB during 2000–2009.Important Findings The spatial pattern of NPP in the YRB was predominantly determined by GPP and further modified by AR.Higher GPP and relatively low AR made the southern Jinshajiang sub-basin the most productive area in NPP in the YRB.A large portion of the YRB experienced a warmer and drier climate trend in the growing season during 2000–2009.In the upper reaches of the basin,possessing a relatively low temperature base,increases in temperature led to greater increases in GPP than those in AR,resulting in greater increased NPP.However,in the middle and lower reaches of the basin where the base temperature is relatively high,increases in temperature led to greater increases in AR than those in GPP,leading to decreases in NPP.Overall,86.7%of the vegetated area showed a consistent GPP and NPP trend through time with 71.3%of the vegetated area having a positive trend both in GPP and NPP,and the remaining 13.3%of vegetated areas showed an opposite trend in GPP and NPP,with positive GPP and negative NPP trajectories dominating(10.1%of vegetated area)the trend.Although climate warming generally had positive effects on vegetation growth in most areas of the basin,areas with increased NPP(74.5%)were less extensive than those with increased GPP(81.4%)due to the wider increase in AR(82.2%).During the study period,increases in AR offset 62%of the total increased GPP,leading to a substantial decline of CUE,particularly in the warmer lower altitude regions in the southeast.Our work reveals the diverse responses of NPP associated with GPP and AR as the climate warms and generally suggests that NPP in the middle and lower sub-basins in the YRB is more sensitive to future climate warming.These findings enhance our understanding of terrestrial ecosystem carbon dynamics in response to global warming and provide a scientific basis for managing ecosystem productivity in the YRB,China.
基金This research comes from the Tianwen-1 Mars exploration mission.The authors gratefully acknowledge the contributions of the entire Tianwen-1 design team.
文摘The clear differences between the atmosphere of Mars and the Earth coupled with the lack of a domestic research basis were significant challenges for the aerodynamic prediction and verification of Tianwen-1.In addition,the Mars entry,descent,and landing(EDL)mission led to specific requirements for the accuracy of the aerodynamic deceleration performance,stability,aerothermal heating,and various complex aerodynamic coupling problems of the entry module.This study analyzes the key and difficult aerodynamic and aerothermodynamic problems related to the Mars EDL process.Then,the study process and results of the design and optimization of the entry module configuration are presented along with the calculations and experiments used to obtain the aerodynamic and aerothermodynamic characteristics in the Martian atmosphere.In addition,the simulation and verification of the low-frequency free oscillation characteristics under a large separation flow are described,and some special aerodynamic coupling problems such as the aeroelastic buffeting response of the trim tab are discussed.Finally,the atmospheric parameters and aerodynamic characteristics obtained from the flight data of the Tianwen-1 entry module are compared with the design data.The data obtained from the aerodynamic design,analysis,and verification of the Tianwen-1 entry module all meet the engineering requirements.In particular,the flight data results for the atmospheric parameters,trim angles of attack,and trim axial forces are within the envelopes of the prediction deviation zones.
基金National Science Foundation(to DEB 0078325 and DEB 0743778).
文摘Land use management affects plant carbon(C)supply and soil environments and hence alters soil nitrogen(N)dynamics,with consequent feedbacks to terrestrial ecosystem productivity.The objective of this study was to better identify mechanisms by which land-use management(clipping and shading)regulates soil N in a tallgrass prairie,OK,USA.Methods We conducted 1-year clipping and shading experiment to investigate the effects of changes in land-use management(soil microclimates,plant C substrate supply and microbial activity)on soil inorganic N(NH_(4)^(+)-N and NO_(3)^(-)-N),net N mineralization and nitrification in a tallgrass prairie.Important Findings Land-use management through clipping and/or shading significantly increased annual mean inorganic N,possibly due to lowered plant N uptake and decreased microbial N immobilization into biomass growth.Shading significantly increased annual mean mineralization rates(P<0.05).Clipping slightly decreased annual mean N nitrification rates whereas shading significantly increased annual mean N nitrification rates.Soil microclimate significantly explained 36%of the variation in NO_(3)^(-)-N concentrations(P=0.004).However,soil respiration,a predictor of plant C substrate supply and microbial activity,was negatively correlated with NH_(4)^(+)-N concentrations(P=0.0009),net N mineralization(P=0.0037)and nitrification rates(P=0.0028)across treatments.Our results suggest that change in C substrate supply andmicrobial activity under clipping and/or shading is a critical control on NH_(4)^(+)-N,net N mineralization and nitrification rates,whereas clipping and shading-induced soil microclimate change can be important for NO_(3)^(-)-N variation in the tallgrass prairie.
基金supported by the National Natural Science Foundation of China(Grant Nos.21771060 and 61271126)the International Science&Technology Cooperation Program of China(Grant No.2016YFE0115100)+2 种基金the Program for Science and Technology Project of Heilongjiang Province(Grant No.JQ2021B002)the Heilongjiang Provincial Natural Science Foundation of China(Grant No.2019LH0320)the Reform and Development Fund Project of Local University supported by the Central Government,Heilongjiang Touyan Innovation Team Program.
文摘As an excellent room temperature sensing material,polyaniline(PANI)needs to be further investigated in the field of high sensitivity and sustainable gas sensors due to its long recovery time and difficulty to complete recovery.The ZnO/PANI film with p-n heterogeneous energy levels have successfully prepared by spraying Zno nanorod synthesized by hydrothermal method on the PANI film rapidly synthesized at the gas-liquid interface.The presence of p-n heterogeneous energy levels enables the ZnO/PANI film to detect 0.1-100 ppm(1 ppm=10^(-6))NH_(3)at room temperature with the response value to 100 ppm NH_(3)doubled(12.96)and the recovery time shortened to 1/5(31.2s).The ability of high response and fast recovery makes the ZnO/PANI filmto be able to detect NH_(3)at room temperature continuously.It provides a new idea for PANI to prepare sustainable room temperature sensor and promotes the development of room temperature sensor in public safety.
文摘In the article titled“Thermal Environment and Aeroheating Mechanism of Protuberances on Mars Entry Capsule”[1],there was an error in the author name details.The first name and surname of all authors were transposed.The correct author names are shown below,and they are corrected in the author list.
基金financially supported by the National Natural Science Foundation of China (32130069)the Special Project for Social Development of Yunnan Province (202103AC100001)+1 种基金the Major Program for Basic Research Project of Yunnan Province (202101BC070002)the Scientific Research Foundation of Education Department of Yunnan Province (2024Y004)。
文摘Soil dissolved organic matter (DOM) is vital in terrestrial ecosystem carbon (C) cycling;however,the regulatory effects of forest types and elevations on soil DOM dynamics in mountain ecosystems remain incompletely understood.Here,we investigated DOM content,spectroscopic characteristics,molecular traits and their potential drivers along an elevational gradient (2600-3500 m) in the Hengduan Mountains.Our results showed that soil dissolved organic C (DOC) content was higher in broad-leaf forest soil (at 2900 m and 3500 m) than in coniferous forest soil (at 2600 m and 3200 m) irrespective of elevation,with a greater amount in wet season than in dry season.Humification index (HIX) trends aligned with the DOC content,while the aromaticity index (AI) showed an inverse relationship.These patterns were linked to the quality of litter carbon sources.Molecular-level analysis of DOM suggested that lignins/CRAM-like structure compounds and tannins predominated in soil DOM,indicating that the molecular composition of soil DOM was typical of plant-derived sources in our study region.Additionally,the relative abundance of lignin compounds decreased gradually with increasing elevation during the dry season.We detected that soil properties (especially,NH_(4)^(+)-N content) predominantly mediated DOM dynamics in dry season,whereas litter traits (i.e.,leaf-DOC content) were the key factors across elevations in wet season.Overall,our results revealed litter traits and soil properties predominantly regulated soil DOM mechanism along elevational gradient,indicating that soil DOM dynamics associated with tree species in alpine mountain ecosystems may differentially influence soil C sequestration under future climate change scenarios.
