Nitrogen(N)enrichment has resulted in widespread alteration of grassland ecosystem processes and functions mainly through disturbance in soil enzyme activities.However,we lack a comprehensive understanding of how N de...Nitrogen(N)enrichment has resulted in widespread alteration of grassland ecosystem processes and functions mainly through disturbance in soil enzyme activities.However,we lack a comprehensive understanding of how N deposition affects specific key soil enzymes that mediate plant-soil feedback of grassland.Here,with a meta-analysis on 1446 cases from field observations in China,we show that N deposition differently affects soil enzymes associated with soil biochemical processes.Specifically,N-promoted C,N,and P-acquiring hydrolase activities significantly increased by 8.73%,7.67%,and 8.69%,respectively,related to an increase in microbial-specific enzyme secretion.The increased relative N availability and soil acidification were two potential mechanisms accounting for the changes in soil enzyme activities with N enrichment.The mixed N addition in combination of NH_(4)NO_(3) and urea showed greater stimulation effect on soil enzyme activities.However,the high rate and long-term N addition tended to weaken the positive responses of soil C-,Nand P-acquiring hydrolase activities to N enrichment.Spatially increased mean annual precipitation and temperature primarily promoted the positive effects of N enrichment on N-and P-acquiring hydrolase activities,and the stimulation of C-and N-acquiring hydrolase activities by N enrichment was intensified with the increase in soil depth.Finally,multimodal inference showed that grassland type was the most important regulator of responses of microbial C,N,and P-acquiring hydrolase activities to N enrichment.This meta-analysis provides a comprehensive insight into understanding the key role of N enrichment in shaping soil enzyme activities of grassland ecosystems.展开更多
The effects of complex microorganisms in composting process of the municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, oxygen consumption, organic mater, and C/N (the ratio of...The effects of complex microorganisms in composting process of the municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, oxygen consumption, organic mater, and C/N (the ratio of carbon and nitrogen). The experimental results shows: complex microorganisms are effective to compose organic matter and speedup composting change into humus.展开更多
Cr_(2)O_(3)was used as grain inhibitor in Ti(C,N)-based cermets with vacuum sintering.The microstructure and mechanical and tribological properties of cermets with Cr_(2)O_(3)and Cr_(3)C_(2)were investigated.The resul...Cr_(2)O_(3)was used as grain inhibitor in Ti(C,N)-based cermets with vacuum sintering.The microstructure and mechanical and tribological properties of cermets with Cr_(2)O_(3)and Cr_(3)C_(2)were investigated.The results show that adding Cr_(2)O_(3)promotes a gray core/gray rim structure formation and finer size of Ti(C,N)hard phase.Compared with the cermet with an equal Cr_(3)C_(2)addition,the cermet with 0.6 wt.%Cr_(2)O_(3)exhibits 16.5%higher transverse rupture strength.This enhancement is likely due to the smaller lattice misfit at the core/rim interface and more uniform Cr distribution in the binder.Additionally,at room temperature(25℃)and 800℃,Cr_(2)O_(3)-containing cermets demonstrate lower coefficients of friction and volume wear ratios than Cr_(3)C_(2)-containing cermets,with the wear ratio difference reaching an order of magnitude.Scanning electron microscopy and X-ray photoelectron spectroscopy results further confirm more oxidation wear in Cr_(2)O_(3)-containing cermets than in Cr_(3)C_(2)-containing cermets.展开更多
The fracture behaviours and notch effects of single-edge-notched(SEN)and double-edge-notched(DEN)2D carbon fibre reinforced carbon matrix composites(C/Cs)were discussed and compared.The fracture behaviours of DEN and ...The fracture behaviours and notch effects of single-edge-notched(SEN)and double-edge-notched(DEN)2D carbon fibre reinforced carbon matrix composites(C/Cs)were discussed and compared.The fracture behaviours of DEN and SEN were performed by tensile and bending load-displacement relationships,and the effects of notch depth on notch sensitivity were determined by DEN specimens.The results from mechanical tests indicated that the SEN exhibited a brittle behaviour with linear elasticity,while the DEN exhibited a ductile behaviour with nonlinearity.It was also found that increasing notch depth and decreasing ligament width can lead to a higher ultimate tensile strength of DEN.On the other hand,the digital image correlation(DIC)method and acoustic emission(AE)system were also applied during the mechanical tests to study the local mechanical characteristics of shear damage,strain concentration and fracture behaviour of 2D C/Cs.The results revealed the mechanisms of notch insensitivity and explained the differences in fracture behaviours between SEN and DEN.展开更多
As droughts become more frequent and severer,understanding tree resilience and its role in mediating drought legacy effects(LEs)is critical for predicting forest ecosystem responses to future droughts and informing fo...As droughts become more frequent and severer,understanding tree resilience and its role in mediating drought legacy effects(LEs)is critical for predicting forest ecosystem responses to future droughts and informing forest management.Both Pinus tabuliformis and Populus davidiana are widely distributed in the Loess Plateau region of western China and play important roles in provision of ecosystem services.In this study we quantified the LEs and resilience,including resistance(Rt)and recovery(Rc),of radial growth(BAI,basal area increment)and intrinsic water use efficiency(iWUE)of the two species,determined the external and internal factors influencing Rt and Rc,and disentangled the respective contribution of Rt and Rc to LEs in the these two tree species.We found either negative or positive legacy effects in BAI(LEBAI)and iWUE(LEiWUE)in both species,mostly lasting for 1-3 years.Species differences were only detected in LEiWUE during the severer drought event.But species variation in resilience did not differ.P.tabuliformis exhibited lower Rt but higher Rc than P.davidiana.Tree diameter and drought intensity were negatively correlated with Rt and Rc;whereas tree age and growth variability positively influenced both resilience components.In P.tabulaeformis,the influence of Rt was stronger on LE than on Rc during the milder droughts,whereas during the severer droughts LE was affected by Rc.The reversed patterns of the effects were exhibited by P.davidiana.Our findings help advance current understanding on the factors driving resilience and how trees use different resilience strategies under different drought conditions to alleviate negative LEs.展开更多
The antioxidant and anti-wrinkle firming effects of a combination of vitamin C(Vc)and black Ganoderma lucidum extract was evaluted.Through the DPPH radical scavenging model and elastase inhibition model,this research ...The antioxidant and anti-wrinkle firming effects of a combination of vitamin C(Vc)and black Ganoderma lucidum extract was evaluted.Through the DPPH radical scavenging model and elastase inhibition model,this research investigates the impact of these substances individually and in combination on antioxidant capabilities and anti-wrinkle firming effects.The results demonstrate that the combination of Vc and black Ganoderma lucidum extract exhibits significant antioxidant abilities at various concentrations,and is more effective than when each is used separately,indicating a synergistic interaction between them.Additionally,the combination also shows significant inhibition of elastase,suggesting potential applications in delaying the aging process of the skin.Furthermore,highperformance liquid chromatography(HPLC)was used to determine if reactions occur among the components of the mixture.The findings reveal that the concentration of Vc in the mixture is very close to the theoretical concentration and relatively stable,suggesting that the components function independently.A quantitative analysis using the Bliss independence model further confirms the synergistic effects of Vc and black Ganoderma lucidum extract at specific ratios,providing a scientific basis for the development of efficacious cosmetic products.展开更多
Codonopsis pilosula(C.pilosula),Astragalus membranaceus(A.membranaceus)and Angelica sinensis(A.sinensis)are three common medicinal and dietary tonifying herbs.In this research,the antimicrobial effects of their aqueou...Codonopsis pilosula(C.pilosula),Astragalus membranaceus(A.membranaceus)and Angelica sinensis(A.sinensis)are three common medicinal and dietary tonifying herbs.In this research,the antimicrobial effects of their aqueous and ethanol extracts were analyzed by using the filter paper diffusion method and microdilution method.The results showed that the aqueous extracts of these three medicinal herbs had no significant inhibitory effect on the growth of four common food-contaminated microorganisms:Escherichia coli(E.coli),Staphylococcus aureus(S.aureus),Candida albicans(C.albicans)and Saccharomyces cerevisiae(S.cerevisiae).Only the C.pilosula ethanol extract(denoted as CEE)could significantly inhibit the growth of S.aureus.The antimicrobial and preservative effects of CEE were investigated by using carrot juice as a model.It was found that CEE exhibited significant synergistic antimicrobial and preservative effects with the chemical preservative benzoic acid.When benzoic acid was reduced to half of its conventional food preservative dosage,the combined addition could completely inhibit the growth of S.aureus within 6 d.CEE was further analyzed by high-performance liquid chromatography(HPLC)and primary mass spectrometry(MS1),and lobetyolin was preliminarily identified as the main active ingredient.The minimum inhibitory concentration(MIC)of lobetyolin was determined to be 40μg/mL when used alone.The cell counting kit-8(CCK-8)assay showed that both CEE and lobetyolin exhibited low cytotoxicity on human normal liver QSG-7701 cells at the preservative dosage,suggesting promising potential for developing safe and effective food preservatives from traditional Chinese medicinal herbs.展开更多
Proton exchange membrane fuel cells(PEMFCs)constitute a promising avenue for environmentally friendly power generation.However,the reliance on unsustainable platinum-based electrocatalysts used at the electrodes poses...Proton exchange membrane fuel cells(PEMFCs)constitute a promising avenue for environmentally friendly power generation.However,the reliance on unsustainable platinum-based electrocatalysts used at the electrodes poses challenges to the commercial viability of PEMFCs.Non-platinum group metal(non-PGM)alternatives,like nitrogen-coordinated transition metals in atomic dispersion(M–N–C catalysts),show significant potential.This work presents a comparative study of two distinct sets of Fe–N–C materials,prepared by pyrolyzing hybrid composites of polyaniline(PANI)and iron(Ⅱ)chloride on a hard template.One set uses bipyridine(BPy)as an additional nitrogen source and iron ligand,offering an innovative approach.The findings reveal that the choice of pyrolysis temperature and atmosphere influences the catalyst properties.The use of ammonia in pyrolysis emerges as a crucial parameter for promoting atomic dispersion of iron,as well as increasing surface area and porosity.The optimal catalyst,prepared using BPy and ammonia,exhibits a half-wave potential of 0.834 V in 0.5 M H_(2)SO_(4)(catalyst loading of 0.6 mg cm^(-2)),a mass activity exceeding 3 A g^(-1)and high stability in acidic electrolyte,positioning it as a promising non-PGM structure in the field.展开更多
Optimizing the interfacial quality of halide perovskites heterojunction to promote the photogenerated charge separation is of great significance in photocatalytic reactions.However,the delicately regulation of interfa...Optimizing the interfacial quality of halide perovskites heterojunction to promote the photogenerated charge separation is of great significance in photocatalytic reactions.However,the delicately regulation of interfacial structure and properties of halide perovskites hybrid is still a big challenge owing to the growth uncontrollability and incompatibility between different constituents.Here we use Bi OBr nanosheets as the start-template to in situ epitaxially grow Cs_(3)Bi_(2)Br_(9)nanosheets by“cosharing”Bi and Br atoms strategy for designing a 2D/2D Cs_(3)Bi_(2)Br_(9)/BiOBr heterojunction.Systematic studies show that the epitaxial heterojunction can optimize the synergistic effect of Bi OBr and Cs_(3)Bi_(2)Br_(9)via the formation of tight-contact interfaces,strong interfacial electronic coupling and charge redistribution,which can not only drive the Z-scheme charge transfer mechanism to greatly promote the spatial separation of electronhole pairs,but also modulate the interfacial electronic structure to facilitate the adsorption and activation of toluene molecules.The heterojunction exhibited 62.3 and 2.4-fold photoactivity improvement for toluene oxidation to benzaldehyde than parental Bi OBr and Cs_(3)Bi_(2)Br_(9),respectively.This study not only proposed a novel dual atom-bridge protocol to engineer high-quality perovskite heterojunctions,but also uncovered the potential of heterojunction in promoting electron-hole separation as well as the application in photocatalytic organic synthesis.展开更多
Purpose: In defining the biological effects of the 10B(n, α)7Li neutron capture reaction, we have previously developed a deterministic parsing model to determine the Compound Biological Effectiveness (CBE) factor in ...Purpose: In defining the biological effects of the 10B(n, α)7Li neutron capture reaction, we have previously developed a deterministic parsing model to determine the Compound Biological Effectiveness (CBE) factor in Borono-Phenyl-Alanine (BPA)-mediated Boron Neutron Capture Therapy (BNCT). In present paper, we demonstrate that the CBE factor is directly and unambiguously derivable by the new formula for any case of intracellular 10Boron (10B) distribution, which is founded on this model for tissues and tumor. Method: To determine the CBE factor, we derive the following new calculation formula founded on the deterministic parsing model with three constants, CBE0, F, n and the eigen value Nth/Nmax. where, Nth and Nmax are the threshold value of boron concentration of N and saturation boron density in tissues and tumor. In order to determine these constants and the eigen values, iterative calculation technique was employed for the CEB factor and Nmax data set previously reported. Results and Conclusion: From the iterative calculation results, it is clear that the calculated CBE factor values obtained are almost identical to the original CBE factors and there is a good correlation between the original CBE factors and Nth/Nmax, when CBE0, F and n are given as 0.5, 8 and 3, respectively. These constants provide a better understanding of different types of intracellular10B distribution.展开更多
The variations in the mechanical and magnetic properties of cold-rolled 20Mn23AlV non-magnetic structural steel after annealing at different temperatures were investigated.The microstructure and precipitation changes ...The variations in the mechanical and magnetic properties of cold-rolled 20Mn23AlV non-magnetic structural steel after annealing at different temperatures were investigated.The microstructure and precipitation changes during annealing were studied by optical microscopy,scanning electron microscopy,and transmission electron microscopy.The results show that recrystallization completed after annealing at 620℃,resulting in grain sizes of approximately 800 nm and the best combination of strength and plasticity.The yield-to-tensile ratio of the non-magnetic structural steel after cold rolling continuously decreases from low to high temperatures after annealing,with the highest value being 0.89 and the lowest value being 0.43,indicating a wide range of yield-to-tensile ratio adjustment.The introduction of numerous dislocations during cold rolling provided favorable nucleation sites for precipitation,leading to abundant precipitation of the fine second-phase V(C,N).The phase composition of the samples remained unchanged as single-phase austenite after annealing,and the relative permeability values were calculated to be less than 1.002,meeting the requirements for non-magnetic steel in terms of magnetic properties.展开更多
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA28110300)National Natural Science Foundation of China(No.U23A2004)+3 种基金Natural Science Foundation of Jilin Province,China(No.YDZJ202201ZYTS522)Science and Technology Cooperation Program between Jilin Province and Chinese Academy of Sciences(No.2023SYHZ0053)Innovation Team Program of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.2023CXTD02)the European Commission under Marie Sk?odowska-Curie(No.101034371)。
文摘Nitrogen(N)enrichment has resulted in widespread alteration of grassland ecosystem processes and functions mainly through disturbance in soil enzyme activities.However,we lack a comprehensive understanding of how N deposition affects specific key soil enzymes that mediate plant-soil feedback of grassland.Here,with a meta-analysis on 1446 cases from field observations in China,we show that N deposition differently affects soil enzymes associated with soil biochemical processes.Specifically,N-promoted C,N,and P-acquiring hydrolase activities significantly increased by 8.73%,7.67%,and 8.69%,respectively,related to an increase in microbial-specific enzyme secretion.The increased relative N availability and soil acidification were two potential mechanisms accounting for the changes in soil enzyme activities with N enrichment.The mixed N addition in combination of NH_(4)NO_(3) and urea showed greater stimulation effect on soil enzyme activities.However,the high rate and long-term N addition tended to weaken the positive responses of soil C-,Nand P-acquiring hydrolase activities to N enrichment.Spatially increased mean annual precipitation and temperature primarily promoted the positive effects of N enrichment on N-and P-acquiring hydrolase activities,and the stimulation of C-and N-acquiring hydrolase activities by N enrichment was intensified with the increase in soil depth.Finally,multimodal inference showed that grassland type was the most important regulator of responses of microbial C,N,and P-acquiring hydrolase activities to N enrichment.This meta-analysis provides a comprehensive insight into understanding the key role of N enrichment in shaping soil enzyme activities of grassland ecosystems.
文摘The effects of complex microorganisms in composting process of the municipal solid waste (MSW) and sludge were examined through inspecting biomass, temperature, oxygen consumption, organic mater, and C/N (the ratio of carbon and nitrogen). The experimental results shows: complex microorganisms are effective to compose organic matter and speedup composting change into humus.
基金Natural Science Foundation of Ningxia,China(No.2023AAC03284)Fundamental Research Funds for the Central Universities Research Project of North Minzu University,China(No.2022XYZCL04)+1 种基金Project of Key Laboratory of Powders and Advanced CeramicsCo-founded by Ningxia and the State Ethnic Affairs Commission,China(No.2103)。
文摘Cr_(2)O_(3)was used as grain inhibitor in Ti(C,N)-based cermets with vacuum sintering.The microstructure and mechanical and tribological properties of cermets with Cr_(2)O_(3)and Cr_(3)C_(2)were investigated.The results show that adding Cr_(2)O_(3)promotes a gray core/gray rim structure formation and finer size of Ti(C,N)hard phase.Compared with the cermet with an equal Cr_(3)C_(2)addition,the cermet with 0.6 wt.%Cr_(2)O_(3)exhibits 16.5%higher transverse rupture strength.This enhancement is likely due to the smaller lattice misfit at the core/rim interface and more uniform Cr distribution in the binder.Additionally,at room temperature(25℃)and 800℃,Cr_(2)O_(3)-containing cermets demonstrate lower coefficients of friction and volume wear ratios than Cr_(3)C_(2)-containing cermets,with the wear ratio difference reaching an order of magnitude.Scanning electron microscopy and X-ray photoelectron spectroscopy results further confirm more oxidation wear in Cr_(2)O_(3)-containing cermets than in Cr_(3)C_(2)-containing cermets.
基金Funded by the National Natural Science Foundation of China(Nos.52072356 and 52032011)。
文摘The fracture behaviours and notch effects of single-edge-notched(SEN)and double-edge-notched(DEN)2D carbon fibre reinforced carbon matrix composites(C/Cs)were discussed and compared.The fracture behaviours of DEN and SEN were performed by tensile and bending load-displacement relationships,and the effects of notch depth on notch sensitivity were determined by DEN specimens.The results from mechanical tests indicated that the SEN exhibited a brittle behaviour with linear elasticity,while the DEN exhibited a ductile behaviour with nonlinearity.It was also found that increasing notch depth and decreasing ligament width can lead to a higher ultimate tensile strength of DEN.On the other hand,the digital image correlation(DIC)method and acoustic emission(AE)system were also applied during the mechanical tests to study the local mechanical characteristics of shear damage,strain concentration and fracture behaviour of 2D C/Cs.The results revealed the mechanisms of notch insensitivity and explained the differences in fracture behaviours between SEN and DEN.
基金the National Natural Science Foundation of China(No.41977149).
文摘As droughts become more frequent and severer,understanding tree resilience and its role in mediating drought legacy effects(LEs)is critical for predicting forest ecosystem responses to future droughts and informing forest management.Both Pinus tabuliformis and Populus davidiana are widely distributed in the Loess Plateau region of western China and play important roles in provision of ecosystem services.In this study we quantified the LEs and resilience,including resistance(Rt)and recovery(Rc),of radial growth(BAI,basal area increment)and intrinsic water use efficiency(iWUE)of the two species,determined the external and internal factors influencing Rt and Rc,and disentangled the respective contribution of Rt and Rc to LEs in the these two tree species.We found either negative or positive legacy effects in BAI(LEBAI)and iWUE(LEiWUE)in both species,mostly lasting for 1-3 years.Species differences were only detected in LEiWUE during the severer drought event.But species variation in resilience did not differ.P.tabuliformis exhibited lower Rt but higher Rc than P.davidiana.Tree diameter and drought intensity were negatively correlated with Rt and Rc;whereas tree age and growth variability positively influenced both resilience components.In P.tabulaeformis,the influence of Rt was stronger on LE than on Rc during the milder droughts,whereas during the severer droughts LE was affected by Rc.The reversed patterns of the effects were exhibited by P.davidiana.Our findings help advance current understanding on the factors driving resilience and how trees use different resilience strategies under different drought conditions to alleviate negative LEs.
文摘The antioxidant and anti-wrinkle firming effects of a combination of vitamin C(Vc)and black Ganoderma lucidum extract was evaluted.Through the DPPH radical scavenging model and elastase inhibition model,this research investigates the impact of these substances individually and in combination on antioxidant capabilities and anti-wrinkle firming effects.The results demonstrate that the combination of Vc and black Ganoderma lucidum extract exhibits significant antioxidant abilities at various concentrations,and is more effective than when each is used separately,indicating a synergistic interaction between them.Additionally,the combination also shows significant inhibition of elastase,suggesting potential applications in delaying the aging process of the skin.Furthermore,highperformance liquid chromatography(HPLC)was used to determine if reactions occur among the components of the mixture.The findings reveal that the concentration of Vc in the mixture is very close to the theoretical concentration and relatively stable,suggesting that the components function independently.A quantitative analysis using the Bliss independence model further confirms the synergistic effects of Vc and black Ganoderma lucidum extract at specific ratios,providing a scientific basis for the development of efficacious cosmetic products.
基金National Natural Science Foundation of China(No.32171958)Transformation Project of Scientific and Technological Achievements of Qinghai Province,China(No.2023-NK-101)Natural Science Foundation of Shanghai,China(No.22ZR1400900)。
文摘Codonopsis pilosula(C.pilosula),Astragalus membranaceus(A.membranaceus)and Angelica sinensis(A.sinensis)are three common medicinal and dietary tonifying herbs.In this research,the antimicrobial effects of their aqueous and ethanol extracts were analyzed by using the filter paper diffusion method and microdilution method.The results showed that the aqueous extracts of these three medicinal herbs had no significant inhibitory effect on the growth of four common food-contaminated microorganisms:Escherichia coli(E.coli),Staphylococcus aureus(S.aureus),Candida albicans(C.albicans)and Saccharomyces cerevisiae(S.cerevisiae).Only the C.pilosula ethanol extract(denoted as CEE)could significantly inhibit the growth of S.aureus.The antimicrobial and preservative effects of CEE were investigated by using carrot juice as a model.It was found that CEE exhibited significant synergistic antimicrobial and preservative effects with the chemical preservative benzoic acid.When benzoic acid was reduced to half of its conventional food preservative dosage,the combined addition could completely inhibit the growth of S.aureus within 6 d.CEE was further analyzed by high-performance liquid chromatography(HPLC)and primary mass spectrometry(MS1),and lobetyolin was preliminarily identified as the main active ingredient.The minimum inhibitory concentration(MIC)of lobetyolin was determined to be 40μg/mL when used alone.The cell counting kit-8(CCK-8)assay showed that both CEE and lobetyolin exhibited low cytotoxicity on human normal liver QSG-7701 cells at the preservative dosage,suggesting promising potential for developing safe and effective food preservatives from traditional Chinese medicinal herbs.
基金funding from the Hellenic Foundation for Research and Innovation(HFRI)under grant agreement No 3655.
文摘Proton exchange membrane fuel cells(PEMFCs)constitute a promising avenue for environmentally friendly power generation.However,the reliance on unsustainable platinum-based electrocatalysts used at the electrodes poses challenges to the commercial viability of PEMFCs.Non-platinum group metal(non-PGM)alternatives,like nitrogen-coordinated transition metals in atomic dispersion(M–N–C catalysts),show significant potential.This work presents a comparative study of two distinct sets of Fe–N–C materials,prepared by pyrolyzing hybrid composites of polyaniline(PANI)and iron(Ⅱ)chloride on a hard template.One set uses bipyridine(BPy)as an additional nitrogen source and iron ligand,offering an innovative approach.The findings reveal that the choice of pyrolysis temperature and atmosphere influences the catalyst properties.The use of ammonia in pyrolysis emerges as a crucial parameter for promoting atomic dispersion of iron,as well as increasing surface area and porosity.The optimal catalyst,prepared using BPy and ammonia,exhibits a half-wave potential of 0.834 V in 0.5 M H_(2)SO_(4)(catalyst loading of 0.6 mg cm^(-2)),a mass activity exceeding 3 A g^(-1)and high stability in acidic electrolyte,positioning it as a promising non-PGM structure in the field.
基金financially supported by the National Natural Science Foundation of China(Nos.22175202,22005351,22365016)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515010180)+3 种基金Program of Guangzhou Science and Technology(No.202201011591)the Science and Technology Innovation Program of Hunan Province(No.2023RC3179)Scientific Research Start-up Fund of Jishou University(No.1122003)support of National Supercomputer Center in Sun Yat-sen University,Guangzhou。
文摘Optimizing the interfacial quality of halide perovskites heterojunction to promote the photogenerated charge separation is of great significance in photocatalytic reactions.However,the delicately regulation of interfacial structure and properties of halide perovskites hybrid is still a big challenge owing to the growth uncontrollability and incompatibility between different constituents.Here we use Bi OBr nanosheets as the start-template to in situ epitaxially grow Cs_(3)Bi_(2)Br_(9)nanosheets by“cosharing”Bi and Br atoms strategy for designing a 2D/2D Cs_(3)Bi_(2)Br_(9)/BiOBr heterojunction.Systematic studies show that the epitaxial heterojunction can optimize the synergistic effect of Bi OBr and Cs_(3)Bi_(2)Br_(9)via the formation of tight-contact interfaces,strong interfacial electronic coupling and charge redistribution,which can not only drive the Z-scheme charge transfer mechanism to greatly promote the spatial separation of electronhole pairs,but also modulate the interfacial electronic structure to facilitate the adsorption and activation of toluene molecules.The heterojunction exhibited 62.3 and 2.4-fold photoactivity improvement for toluene oxidation to benzaldehyde than parental Bi OBr and Cs_(3)Bi_(2)Br_(9),respectively.This study not only proposed a novel dual atom-bridge protocol to engineer high-quality perovskite heterojunctions,but also uncovered the potential of heterojunction in promoting electron-hole separation as well as the application in photocatalytic organic synthesis.
文摘Purpose: In defining the biological effects of the 10B(n, α)7Li neutron capture reaction, we have previously developed a deterministic parsing model to determine the Compound Biological Effectiveness (CBE) factor in Borono-Phenyl-Alanine (BPA)-mediated Boron Neutron Capture Therapy (BNCT). In present paper, we demonstrate that the CBE factor is directly and unambiguously derivable by the new formula for any case of intracellular 10Boron (10B) distribution, which is founded on this model for tissues and tumor. Method: To determine the CBE factor, we derive the following new calculation formula founded on the deterministic parsing model with three constants, CBE0, F, n and the eigen value Nth/Nmax. where, Nth and Nmax are the threshold value of boron concentration of N and saturation boron density in tissues and tumor. In order to determine these constants and the eigen values, iterative calculation technique was employed for the CEB factor and Nmax data set previously reported. Results and Conclusion: From the iterative calculation results, it is clear that the calculated CBE factor values obtained are almost identical to the original CBE factors and there is a good correlation between the original CBE factors and Nth/Nmax, when CBE0, F and n are given as 0.5, 8 and 3, respectively. These constants provide a better understanding of different types of intracellular10B distribution.
基金support from the Gansu Province Science and Technology Major Project(22ZD6GA008)Commissioner for Science,Technology Program of China Gansu Province(23CXA0013)+1 种基金National Natural Science Foundation of China(NSFC)(52061022)Jiayuguan City Science and Technology Major Project of China Gansu Province(22-02).
文摘The variations in the mechanical and magnetic properties of cold-rolled 20Mn23AlV non-magnetic structural steel after annealing at different temperatures were investigated.The microstructure and precipitation changes during annealing were studied by optical microscopy,scanning electron microscopy,and transmission electron microscopy.The results show that recrystallization completed after annealing at 620℃,resulting in grain sizes of approximately 800 nm and the best combination of strength and plasticity.The yield-to-tensile ratio of the non-magnetic structural steel after cold rolling continuously decreases from low to high temperatures after annealing,with the highest value being 0.89 and the lowest value being 0.43,indicating a wide range of yield-to-tensile ratio adjustment.The introduction of numerous dislocations during cold rolling provided favorable nucleation sites for precipitation,leading to abundant precipitation of the fine second-phase V(C,N).The phase composition of the samples remained unchanged as single-phase austenite after annealing,and the relative permeability values were calculated to be less than 1.002,meeting the requirements for non-magnetic steel in terms of magnetic properties.
