Straw return is the main practice used to increase soil organic matter(SOM)in agricultural ecosystems.To increase the efficiency of straw conversion to SOM,a large number of microbial inoculants have been developed.Ho...Straw return is the main practice used to increase soil organic matter(SOM)in agricultural ecosystems.To increase the efficiency of straw conversion to SOM,a large number of microbial inoculants have been developed.However,their effects are poor because of the complex water and temperature conditions,especially under sodic conditions.Small molecules can rapidly shift soil microbial communities and improve their ability to transform exogenous organic matter into SOM,providing a new direction for promoting high-efficiency straw conversion into SOM.In this study,we conducted a^(13)C-labeled straw degradation experiment using small molecules derived from lignin(LSMs)and humus(HSMs)as activators,investigating their effects on the microbial communities and formation of newly formed mineral-associated(^(13)C-MAOM)and particulate(^(13)C-POM)organic matter from^(13)C-labeled straw in both sodic and non-sodic soils.The^(13)C-labeled straw was mainly converted into^(13)C-MAOM,accounting for 73.97%–92.67%of the newly formed SOM.Biopolymer-derived small molecules decreased the exchangeable sodium percentage(ESP),but increased contents of^(13)C-MAOM and^(13)C-POM by shifting microbial communities,strengthening microbial cross-trophic interactions,enhancing enzyme activities,and increasing microbial residues in both soils.Addition of HSMs had greater impacts on^(13)C-MAOM formation than LSM addition.The^(13)C-MAOM and^(13)C-POM formation negatively correlated with ESP,but positively correlated with microbial cross-trophic interactions and enzyme activities in both soils.Our results suggest that biopolymer-derived small molecules promote^(13)C-MAOM and^(13)C-POM formation associated with microbial cross-trophic interactions between protistan predators and primary decomposers.Our study provides scientific support for future attempts to stimulate microbial cross-trophic interactions for boosting SOM accumulation under stressed conditions.展开更多
As a classical complex network model, scale-free network is widely used and studied. And motifs, as a high-order subgraph structure, frequently appear in scale-free networks, and have a great influence on the structur...As a classical complex network model, scale-free network is widely used and studied. And motifs, as a high-order subgraph structure, frequently appear in scale-free networks, and have a great influence on the structural integrity, functional integrity and dynamics of the networks. In order to overcome the shortcomings in the existing work on the robustness of complex networks, only nodes or edges are considered, while the defects of high-order structure in the network are ignored.From the perspective of network motif, we propose an entropy of node degree distribution based on motif to measure the robustness of scale-free networks under random attacks. The effectiveness and superiority of our method are verified and analyzed in the BA scale-free networks.展开更多
As the western end point of continental collision between the Indian and Eurasian plates, Pamir is an ideal place to research uplifting mechanisms in the Tibetan plateau. In this study, 141 644 Pn arrivals were used t...As the western end point of continental collision between the Indian and Eurasian plates, Pamir is an ideal place to research uplifting mechanisms in the Tibetan plateau. In this study, 141 644 Pn arrivals were used to obtain seismic wave velocities and anisotropy in the uppermost mantle beneath Pamir and its adjacent regions by performing tomographic inversion of Pn travel times. The data were selected from multiple databases, including ISC/EHB, the Annual Bulletin of Chinese Earthquakes, and regional bulletins of Xinjiang. The tomography results reveal significant features with high resolution and correlate well with geological structures. The main results are as follows： （1） The Pn wave velocities are particularly high in the old stable blocks such as Tarim basin, Indian plate and Tajik basin, while the low Pn velocities always lie in tectonically active regions like the western Tibetan plateau, Pamir, Tianshan and Hindu Kush. （2） Strong Pn anisotropy is found beneath the Indian-Eurasian collision zone; its direction is parallel to the collision are and nearly perpendicular to both the direction of maximum compression stress and relative crustal movement. The result is probably caused by the pure shear deformation in the uppermost mantle of the collision zone. （3） A geodynamic continent-continent collision model is proposed to show anisotropy and collision mechanisms between the Indian plate and the Tarim and Tajik basins.展开更多
A highly sensitive optical fiber temperature sensor based on a section of liquid-filled silica capillary tube(SCT)between single mode fibers is proposed. Two micro-holes are drilled on two sides of SCT directly by usi...A highly sensitive optical fiber temperature sensor based on a section of liquid-filled silica capillary tube(SCT)between single mode fibers is proposed. Two micro-holes are drilled on two sides of SCT directly by using femtosecond laser micromachining, and liquid polymer is filled into the SCT through the micro-holes without any air bubbles and then sealed by using ultra-violet(UV) cure adhesive. The sidewall of the SCT forms a Fabry–Perot resonator, and loss peaks are achieved in the transmission spectrum of the SCT at the resonant wavelength. The resonance condition can be influenced by the refractive index variation of the liquid polymer filled in SCT, which is sensitive to temperature due to its high thermooptical coefficient(-2.98 × 10^-4℃^-1). The experimental result shows that the temperature sensitivity of the proposed fiber structure reaches 5.09 nm/℃ with a perfect linearity of 99.8%. In addition, it exhibits good repeatability and reliability in temperature sensing application.展开更多
Macroaggregate organic carbon(Macro-OC)accumulation in paddy soils is of great significance in promoting multiple agroecosystem services.However,the effects of different fertilization practices on Macro-OC accumulatio...Macroaggregate organic carbon(Macro-OC)accumulation in paddy soils is of great significance in promoting multiple agroecosystem services.However,the effects of different fertilization practices on Macro-OC accumulation in paddy soils at the regional scale have not been comprehensively investigated.Here,we conducted long-term fertilization field experiments at four sites,Taoyuan,Wangcheng,Jinxian,and Suzhou,in the subtropical area of China to reveal the effects of inorganic and organic-inorganic(OIF)fertilization on Macro-OC accumulation and its relationships with important microbial traits(the abundance ratio of GH48:cbhI genes and the richness of keystone bacterial taxa)in paddy soils.The results showed that long-term fertilization(particularly OIF)significantly increased the content of Macro-OC,which mainly consisted of particulate organic carbon(C).Organic-inorganic fertilization decreased the percentage of O-alkyl C but increased the percentages of alkyl,aromatic,and phenolic C.Organic-inorganic fertilization promoted the abundance of the bacterial cellulose-degrading gene GH48 retrieved from macroaggregates.The orders Anaerolineales,Bacillales,and Clostridiales were identified as keystone bacterial taxa in macroaggregates and were significantly correlated with the physical fraction and chemical structure of Macro-OC.Structural equation modeling revealed that fertilization-induced changes in soil pH and C:N ratio affected the richness of Anaerolineales,Bacillales,and Clostridiales,which was strongly associated with the increase of percentages of aromatic and phenolic C and further facilitated Macro-OC accumulation.Together,these results suggested that OIF promoted Macro-OC accumulation associated with key bacterial populations in paddy soils.The results provide an important basis for boosting soil C accrual in the subtropical rice-growing areas.展开更多
miRNAs play important roles in the post-transcriptional regulation of most transcripts and control several biological processes. We have shown that miR-200b regulates VEGF and miR-146a regulates ECM （extracellular ma...miRNAs play important roles in the post-transcriptional regulation of most transcripts and control several biological processes. We have shown that miR-200b regulates VEGF and miR-146a regulates ECM （extracellular matrix） protein, FN （fibronectin） production. We examined the effects of these two miRNAs in wound healing in vitro and in animals with or without diabetes. Microvascular ECs （endothelial cells） with or without miR inhibitor （antagomir） transfection were tested for VEGF and FN production. Scratch assays and angiogenesis assays were performed. Wounds in the back of mice with or without streptozotocin-induced diabetes were treated with antagomirs alone or in combinations. The wounds were measured and tissues were examined for mRNAs, proteins and miRNAs and examined histologically. In the ECs, miR-200b or miR-146a inhibitors increased VEGF and FN production, cell migration and tube formation. Wound healing in the animals, along with increased production of specific proteins were accelerated by miR-200b or miR-146a inhibitor treatment and was pronounced when these two were combined In diabetes, although delayed, similar patterns were seen. These results indicated that combination of miR-146a and miR-200b inhibitor treatment is useful in wound healing both in normal and in diabetic conditions, miRNA mediated wound healing may potentially constitute a novel therapeutic approach.展开更多
Protists are essential components of the rhizosphere microbiome,which is crucial for plant growth,but little is known about the relationship between plant growth and rhizosphere protists under salinity stress.Here we ...Protists are essential components of the rhizosphere microbiome,which is crucial for plant growth,but little is known about the relationship between plant growth and rhizosphere protists under salinity stress.Here we investigated wheat(Triticum aestivum L.)rhizosphere protistan communities under naturally occurring salinity(NOS)and irrigation-reduced salinity(IRS),and linked a plant salinity stress index(PSSI)to different protistan groups in a nontidal coastal saline soil.We found that the PSSI was significantly correlated with rhizosphere cercozoan communities(including bacterivores,eukaryvores,and omnivores)and that these communities were important predictors of the PSSI.Structural equation modeling suggested that root exudation-induced change in bacterial community composition affected the communities of bacterivorous and omnivorous Cercozoa,which were significantly associated with the PSSI across wheat cultivars.Network analysis indicated more complex connections between rhizosphere bacteria and their protistan predators under IRS than under NOS,implying that alleviation of salinity stress promotes the predation of specific cercozoans on bacteria in rhizospheres.Moreover,the Cercomonas directa inoculation was conducive to alleviation of salinity stress.Taken together,these results suggest that the physiological response of wheat plants to salinity stress is closely linked to rhizosphere Cercozoa through trophic regulation within the rhizosphere microbiome.展开更多
Metal-free carbon-based catalysts exhibit diverse electrocatalytic performances in CO_(2) reduction reaction(CO_(2)RR),but the attributions and contributions of active sites are still confusing to date.Herein,the hier...Metal-free carbon-based catalysts exhibit diverse electrocatalytic performances in CO_(2) reduction reaction(CO_(2)RR),but the attributions and contributions of active sites are still confusing to date.Herein,the hierarchical carbon nanocages(hCNC)doped with different heteroatoms(B,N,P,S)are prepared to examine the impact of dopants on the competitive CO_(2)RR and hydrogen evolution reaction(HER).The hCNC and P-doped hCNC show little CO_(2)RR activity,B-and S-doped hCNC show weak CO_(2)RR activity,while N-doped hCNC presents high CO_(2)RR activity.The CO Faradaic efficiency(FECO)of N-containing hCNC increases almost linearly with increasing the N content,even with the co-existing B or P.S and SN-doped hCNC more facilitate the HER.16 doping configurations are constructed,and up to 53 sites are examined CO_(2) H2O H2 CO*H*COOH*CO for the electrochemical activities with a constant potential modelling method.The pyridinic-N(N^(*))is the best active site for CO_(2)RR to CO,while CBO_(2)H_(2)-1(αC^(*)),CBO_(2)H_(2)-2(γC^(*)),NO-1(βC^(*)),PO_(2)H-3(αC^(*))and SO_(3)H-3(δC^(*))are active for HER.The optimized FECO achieves 83.6%for N-doped hCNC with 9.54 at.%nitrogen,and S-doped hCNC reaches ca.30 mA·cm^(-2) current density for HER.This study unveils the structure-performance correlation of heteroatom-doped hCNC,which is conducive to the rational design of advanced metal-free carbon-based catalysts.展开更多
A three-dimensional (3D) scratch model is proposed to investigate the effects of yield strength of both coatings and substrates.With the help of combined Coulomb and plastic friction,the obtained results comprehensive...A three-dimensional (3D) scratch model is proposed to investigate the effects of yield strength of both coatings and substrates.With the help of combined Coulomb and plastic friction,the obtained results comprehensively interpret the experimental phenomena in most metals that with the growth of hardness after heat treatment the scratch friction coefficient (SFC) increases.This interpretation could not be done before.Scratch tests on the surface with or without the coating are discussed.Without the coating the SFC increases due to the decrease of the area with plastic slippage and/or the increase of friction stress during the increase of the yield strength in the material.With a softer substrate the friction stress decreases but the SFC increases,which is caused by the growth of the entire contact area and surface deformation.Conversely,with a stronger substrate the SFC decreases due to an intensified plastic slippage.The obtained results pave a new way to understanding the effects of yield strength on scratch tests,interpret experimental phenomena,and should be helpful for an optimum design in experiments.展开更多
Various phenomena(fracture,phase transformations,and chemical reactions)studied under extreme pressures in diamond anvil cell are strongly affected by fields of all components of stress and plastic strain tensors.Howe...Various phenomena(fracture,phase transformations,and chemical reactions)studied under extreme pressures in diamond anvil cell are strongly affected by fields of all components of stress and plastic strain tensors.However,they could not be measured.Here,we suggest a coupled experimental−theoretical−computational approach that allowed us(using published experimental data)to refine,calibrate,and verify models for elastoplastic behavior and contact friction for tungsten(W)and diamond up to 400 GPa and reconstruct fields of all components of stress and large plastic strain tensors in W and diamond.Despite the generally accepted strain-induced anisotropy,strain hardening,and path-dependent plasticity,here we showed that W after large plastic strains behaves as isotropic and perfectly plastic with path-independent surface of perfect plasticity.Moreover,scale-independence of elastoplastic properties is found even for such large field gradients.Obtained results open opportunities for quantitative extreme stress science and reaching record high pressures.展开更多
Efficient,durable and economic electrocatalysts are crucial for commercializing water electrolysis technology.Herein,we report an advanced bifunctional electrocatalyst for alkaline water splitting by growing NiFe-laye...Efficient,durable and economic electrocatalysts are crucial for commercializing water electrolysis technology.Herein,we report an advanced bifunctional electrocatalyst for alkaline water splitting by growing NiFe-layered double hydroxide(NiFe-LDH)nanosheet arrays on the conductive NiMo-based nanorods deposited on Ni foam to form a three-dimensional(3D)architecture,which exhibits exceptional performances for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).In overall water splitting,only the low operation voltages of 1.45/1.61 V are required to reach the current density of 10/500 mA·cm^(-2),and the continuous water splitting at an industrial-level current density of 500 mA·cm^(-2) shows a negligible degradation(1.8%)of the cell voltage over 1000 h.The outstanding performance is ascribed to the synergism of the HER-active NiMo-based nanorods and the OER-active NiFe-LDH nanosheet arrays of the hybridized 3D architecture.Specifically,the dense NiFe-LDH nanosheet arrays enhance the local pH on cathode by retarding OH-diffusion and enlarge the electrochemically active surface area on anode,while the conductive NiMo-based nanorods on Ni foam much decrease the charge-transfer resistances of both electrodes.This study provides an efficient strategy to explore advanced bifunctional electrocatalysts for overall water splitting by rationally hybridizing HER-and OER-active components.展开更多
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDA28110100 and XDA28020202)the National Key Research and Development Program of China(No.2022YFD1500203)+3 种基金the National Natural Science Foundation of China(No.42177332)the China Agriculture Research System(Nos.CARS-03 and CARS-52)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2023325)the Anhui Provincial Key Research and Development Project,China(No.2023n06020056).
文摘Straw return is the main practice used to increase soil organic matter(SOM)in agricultural ecosystems.To increase the efficiency of straw conversion to SOM,a large number of microbial inoculants have been developed.However,their effects are poor because of the complex water and temperature conditions,especially under sodic conditions.Small molecules can rapidly shift soil microbial communities and improve their ability to transform exogenous organic matter into SOM,providing a new direction for promoting high-efficiency straw conversion into SOM.In this study,we conducted a^(13)C-labeled straw degradation experiment using small molecules derived from lignin(LSMs)and humus(HSMs)as activators,investigating their effects on the microbial communities and formation of newly formed mineral-associated(^(13)C-MAOM)and particulate(^(13)C-POM)organic matter from^(13)C-labeled straw in both sodic and non-sodic soils.The^(13)C-labeled straw was mainly converted into^(13)C-MAOM,accounting for 73.97%–92.67%of the newly formed SOM.Biopolymer-derived small molecules decreased the exchangeable sodium percentage(ESP),but increased contents of^(13)C-MAOM and^(13)C-POM by shifting microbial communities,strengthening microbial cross-trophic interactions,enhancing enzyme activities,and increasing microbial residues in both soils.Addition of HSMs had greater impacts on^(13)C-MAOM formation than LSM addition.The^(13)C-MAOM and^(13)C-POM formation negatively correlated with ESP,but positively correlated with microbial cross-trophic interactions and enzyme activities in both soils.Our results suggest that biopolymer-derived small molecules promote^(13)C-MAOM and^(13)C-POM formation associated with microbial cross-trophic interactions between protistan predators and primary decomposers.Our study provides scientific support for future attempts to stimulate microbial cross-trophic interactions for boosting SOM accumulation under stressed conditions.
基金Project supported by the National Natural Science Foundation of China (Grant No. 62006169)the Youth Natural Science Foundation of Shanxi Province, China (Grant No. 201901D211304)+1 种基金the China Postdoctoral Science Foundation (Grant No. 2021M692400)the Science and Technology Innovation Projects of Universities in Shanxi Province, China (Grant No. 2020L0021)。
文摘As a classical complex network model, scale-free network is widely used and studied. And motifs, as a high-order subgraph structure, frequently appear in scale-free networks, and have a great influence on the structural integrity, functional integrity and dynamics of the networks. In order to overcome the shortcomings in the existing work on the robustness of complex networks, only nodes or edges are considered, while the defects of high-order structure in the network are ignored.From the perspective of network motif, we propose an entropy of node degree distribution based on motif to measure the robustness of scale-free networks under random attacks. The effectiveness and superiority of our method are verified and analyzed in the BA scale-free networks.
基金financially supported jointly by the National Natural Science Foundation of China (Grant Nos. 41174036 and 41021001)the foundation from Chinese Academy of Sciences (Grant No. KZCX2-EW-QN102)
文摘As the western end point of continental collision between the Indian and Eurasian plates, Pamir is an ideal place to research uplifting mechanisms in the Tibetan plateau. In this study, 141 644 Pn arrivals were used to obtain seismic wave velocities and anisotropy in the uppermost mantle beneath Pamir and its adjacent regions by performing tomographic inversion of Pn travel times. The data were selected from multiple databases, including ISC/EHB, the Annual Bulletin of Chinese Earthquakes, and regional bulletins of Xinjiang. The tomography results reveal significant features with high resolution and correlate well with geological structures. The main results are as follows： （1） The Pn wave velocities are particularly high in the old stable blocks such as Tarim basin, Indian plate and Tajik basin, while the low Pn velocities always lie in tectonically active regions like the western Tibetan plateau, Pamir, Tianshan and Hindu Kush. （2） Strong Pn anisotropy is found beneath the Indian-Eurasian collision zone; its direction is parallel to the collision are and nearly perpendicular to both the direction of maximum compression stress and relative crustal movement. The result is probably caused by the pure shear deformation in the uppermost mantle of the collision zone. （3） A geodynamic continent-continent collision model is proposed to show anisotropy and collision mechanisms between the Indian plate and the Tarim and Tajik basins.
基金Project supported by the Scientific Research Project of Institutions of Higher Learning in Inner Mongolia Autonomous Region,China(Grant No.NJZY19214)
文摘A highly sensitive optical fiber temperature sensor based on a section of liquid-filled silica capillary tube(SCT)between single mode fibers is proposed. Two micro-holes are drilled on two sides of SCT directly by using femtosecond laser micromachining, and liquid polymer is filled into the SCT through the micro-holes without any air bubbles and then sealed by using ultra-violet(UV) cure adhesive. The sidewall of the SCT forms a Fabry–Perot resonator, and loss peaks are achieved in the transmission spectrum of the SCT at the resonant wavelength. The resonance condition can be influenced by the refractive index variation of the liquid polymer filled in SCT, which is sensitive to temperature due to its high thermooptical coefficient(-2.98 × 10^-4℃^-1). The experimental result shows that the temperature sensitivity of the proposed fiber structure reaches 5.09 nm/℃ with a perfect linearity of 99.8%. In addition, it exhibits good repeatability and reliability in temperature sensing application.
基金supported by the National Key R&D Program of China(Nos.2022YFD1500401 and 2022YFD1500203)the National Natural Science Foundation of China(Nos.42177332 and 41967002)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDA24020104 and XDA28020203)the China Agriculture Research System(Nos.CARS-03-15 and CARS-52)。
文摘Macroaggregate organic carbon(Macro-OC)accumulation in paddy soils is of great significance in promoting multiple agroecosystem services.However,the effects of different fertilization practices on Macro-OC accumulation in paddy soils at the regional scale have not been comprehensively investigated.Here,we conducted long-term fertilization field experiments at four sites,Taoyuan,Wangcheng,Jinxian,and Suzhou,in the subtropical area of China to reveal the effects of inorganic and organic-inorganic(OIF)fertilization on Macro-OC accumulation and its relationships with important microbial traits(the abundance ratio of GH48:cbhI genes and the richness of keystone bacterial taxa)in paddy soils.The results showed that long-term fertilization(particularly OIF)significantly increased the content of Macro-OC,which mainly consisted of particulate organic carbon(C).Organic-inorganic fertilization decreased the percentage of O-alkyl C but increased the percentages of alkyl,aromatic,and phenolic C.Organic-inorganic fertilization promoted the abundance of the bacterial cellulose-degrading gene GH48 retrieved from macroaggregates.The orders Anaerolineales,Bacillales,and Clostridiales were identified as keystone bacterial taxa in macroaggregates and were significantly correlated with the physical fraction and chemical structure of Macro-OC.Structural equation modeling revealed that fertilization-induced changes in soil pH and C:N ratio affected the richness of Anaerolineales,Bacillales,and Clostridiales,which was strongly associated with the increase of percentages of aromatic and phenolic C and further facilitated Macro-OC accumulation.Together,these results suggested that OIF promoted Macro-OC accumulation associated with key bacterial populations in paddy soils.The results provide an important basis for boosting soil C accrual in the subtropical rice-growing areas.
文摘miRNAs play important roles in the post-transcriptional regulation of most transcripts and control several biological processes. We have shown that miR-200b regulates VEGF and miR-146a regulates ECM （extracellular matrix） protein, FN （fibronectin） production. We examined the effects of these two miRNAs in wound healing in vitro and in animals with or without diabetes. Microvascular ECs （endothelial cells） with or without miR inhibitor （antagomir） transfection were tested for VEGF and FN production. Scratch assays and angiogenesis assays were performed. Wounds in the back of mice with or without streptozotocin-induced diabetes were treated with antagomirs alone or in combinations. The wounds were measured and tissues were examined for mRNAs, proteins and miRNAs and examined histologically. In the ECs, miR-200b or miR-146a inhibitors increased VEGF and FN production, cell migration and tube formation. Wound healing in the animals, along with increased production of specific proteins were accelerated by miR-200b or miR-146a inhibitor treatment and was pronounced when these two were combined In diabetes, although delayed, similar patterns were seen. These results indicated that combination of miR-146a and miR-200b inhibitor treatment is useful in wound healing both in normal and in diabetic conditions, miRNA mediated wound healing may potentially constitute a novel therapeutic approach.
基金financially supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDA24020104,XDA28110100,XDA28020203)the National Key R&D Program of China(Grant Nos.2022YFD1500203,2022YFD1500401)+2 种基金the China Agriculture Research System(Grant Nos.CARS-03,CARS-52)the National Natural Science Foundation of China(Grant No.42177332)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2023325).
文摘Protists are essential components of the rhizosphere microbiome,which is crucial for plant growth,but little is known about the relationship between plant growth and rhizosphere protists under salinity stress.Here we investigated wheat(Triticum aestivum L.)rhizosphere protistan communities under naturally occurring salinity(NOS)and irrigation-reduced salinity(IRS),and linked a plant salinity stress index(PSSI)to different protistan groups in a nontidal coastal saline soil.We found that the PSSI was significantly correlated with rhizosphere cercozoan communities(including bacterivores,eukaryvores,and omnivores)and that these communities were important predictors of the PSSI.Structural equation modeling suggested that root exudation-induced change in bacterial community composition affected the communities of bacterivorous and omnivorous Cercozoa,which were significantly associated with the PSSI across wheat cultivars.Network analysis indicated more complex connections between rhizosphere bacteria and their protistan predators under IRS than under NOS,implying that alleviation of salinity stress promotes the predation of specific cercozoans on bacteria in rhizospheres.Moreover,the Cercomonas directa inoculation was conducive to alleviation of salinity stress.Taken together,these results suggest that the physiological response of wheat plants to salinity stress is closely linked to rhizosphere Cercozoa through trophic regulation within the rhizosphere microbiome.
基金This work was jointly supported by the National Key Research and Development Program of China(No.2021YFA1500900)the National Natural Science Foundation of China(No.52071174)the Natural Science Foundation of Jiangsu Province,Major Project(No.BK20212005)。
文摘Metal-free carbon-based catalysts exhibit diverse electrocatalytic performances in CO_(2) reduction reaction(CO_(2)RR),but the attributions and contributions of active sites are still confusing to date.Herein,the hierarchical carbon nanocages(hCNC)doped with different heteroatoms(B,N,P,S)are prepared to examine the impact of dopants on the competitive CO_(2)RR and hydrogen evolution reaction(HER).The hCNC and P-doped hCNC show little CO_(2)RR activity,B-and S-doped hCNC show weak CO_(2)RR activity,while N-doped hCNC presents high CO_(2)RR activity.The CO Faradaic efficiency(FECO)of N-containing hCNC increases almost linearly with increasing the N content,even with the co-existing B or P.S and SN-doped hCNC more facilitate the HER.16 doping configurations are constructed,and up to 53 sites are examined CO_(2) H2O H2 CO*H*COOH*CO for the electrochemical activities with a constant potential modelling method.The pyridinic-N(N^(*))is the best active site for CO_(2)RR to CO,while CBO_(2)H_(2)-1(αC^(*)),CBO_(2)H_(2)-2(γC^(*)),NO-1(βC^(*)),PO_(2)H-3(αC^(*))and SO_(3)H-3(δC^(*))are active for HER.The optimized FECO achieves 83.6%for N-doped hCNC with 9.54 at.%nitrogen,and S-doped hCNC reaches ca.30 mA·cm^(-2) current density for HER.This study unveils the structure-performance correlation of heteroatom-doped hCNC,which is conducive to the rational design of advanced metal-free carbon-based catalysts.
文摘A three-dimensional (3D) scratch model is proposed to investigate the effects of yield strength of both coatings and substrates.With the help of combined Coulomb and plastic friction,the obtained results comprehensively interpret the experimental phenomena in most metals that with the growth of hardness after heat treatment the scratch friction coefficient (SFC) increases.This interpretation could not be done before.Scratch tests on the surface with or without the coating are discussed.Without the coating the SFC increases due to the decrease of the area with plastic slippage and/or the increase of friction stress during the increase of the yield strength in the material.With a softer substrate the friction stress decreases but the SFC increases,which is caused by the growth of the entire contact area and surface deformation.Conversely,with a stronger substrate the SFC decreases due to an intensified plastic slippage.The obtained results pave a new way to understanding the effects of yield strength on scratch tests,interpret experimental phenomena,and should be helpful for an optimum design in experiments.
基金We thank Bing Li for sharing some details for sample in their paper6.Support from Army Research Office(Grant W911NF-17-1-0225)National Science Foundation(Grant DMR-1904830)+1 种基金Office of Naval Research(Grant N00014-19-1-2082)is greatly acknowledgedSome computations have been performed using the Extreme Science and Engineering Discovery Environment(XSEDE allocations TG MSS170003 and MSS170015).
文摘Various phenomena(fracture,phase transformations,and chemical reactions)studied under extreme pressures in diamond anvil cell are strongly affected by fields of all components of stress and plastic strain tensors.However,they could not be measured.Here,we suggest a coupled experimental−theoretical−computational approach that allowed us(using published experimental data)to refine,calibrate,and verify models for elastoplastic behavior and contact friction for tungsten(W)and diamond up to 400 GPa and reconstruct fields of all components of stress and large plastic strain tensors in W and diamond.Despite the generally accepted strain-induced anisotropy,strain hardening,and path-dependent plasticity,here we showed that W after large plastic strains behaves as isotropic and perfectly plastic with path-independent surface of perfect plasticity.Moreover,scale-independence of elastoplastic properties is found even for such large field gradients.Obtained results open opportunities for quantitative extreme stress science and reaching record high pressures.
基金supported by the National Key Research and Development Program of China(No.2021YFA1500900)the National Natural Science Foundation of China(Nos.52071174,21832003,21972061)+1 种基金the Natural Science Foundation of Jiangsu Province,Major Project(No.BK20212005)the Foundation of Science and Technology of Suzhou(No.SYC2022102).
文摘Efficient,durable and economic electrocatalysts are crucial for commercializing water electrolysis technology.Herein,we report an advanced bifunctional electrocatalyst for alkaline water splitting by growing NiFe-layered double hydroxide(NiFe-LDH)nanosheet arrays on the conductive NiMo-based nanorods deposited on Ni foam to form a three-dimensional(3D)architecture,which exhibits exceptional performances for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).In overall water splitting,only the low operation voltages of 1.45/1.61 V are required to reach the current density of 10/500 mA·cm^(-2),and the continuous water splitting at an industrial-level current density of 500 mA·cm^(-2) shows a negligible degradation(1.8%)of the cell voltage over 1000 h.The outstanding performance is ascribed to the synergism of the HER-active NiMo-based nanorods and the OER-active NiFe-LDH nanosheet arrays of the hybridized 3D architecture.Specifically,the dense NiFe-LDH nanosheet arrays enhance the local pH on cathode by retarding OH-diffusion and enlarge the electrochemically active surface area on anode,while the conductive NiMo-based nanorods on Ni foam much decrease the charge-transfer resistances of both electrodes.This study provides an efficient strategy to explore advanced bifunctional electrocatalysts for overall water splitting by rationally hybridizing HER-and OER-active components.
