Even though theymight not haveenough food intheir own stom-achs,Tibetan peasantswould feed their draughtcattle with the best food,asthey depended on them forplowing. Such good treat-ment lasted until the ani-mals died...Even though theymight not haveenough food intheir own stom-achs,Tibetan peasantswould feed their draughtcattle with the best food,asthey depended on them forplowing. Such good treat-ment lasted until the ani-mals died,after which,some peasants would burythem in their own fields,展开更多
Hainan is transforming into a world-class hub,with expanded free trade policies,robust infrastructure and global business opportunities The Hainan Free Trade Port(FTP)officially launched island-wide special customs op...Hainan is transforming into a world-class hub,with expanded free trade policies,robust infrastructure and global business opportunities The Hainan Free Trade Port(FTP)officially launched island-wide special customs operations on 18 December 2025.One month in,reporters from China International Communications Group(CICG)conducted an exclusive interview with Feng Fei,secretary of the Hainan Provincial Committee of the Communist Party of China(CPC)and chairman of the Standing Committee of the Hainan Provincial People’s Congress.展开更多
The Hainan Free Trade Port’s implementation of special customs operations marks a significant stride in China’s institutional opening-up,spurring global trade and investment flows.THE Hainan Free Trade Port(FTP)repr...The Hainan Free Trade Port’s implementation of special customs operations marks a significant stride in China’s institutional opening-up,spurring global trade and investment flows.THE Hainan Free Trade Port(FTP)represents a significant step forward in China’s pursuit of high-standard opening-up and greater engagement in economic globalization.展开更多
THE Hainan Free Trade Port(FTP)officially launched island-wide special customs operations on December 18,2025.One month in,a reporting team from China International Communications Group(CICG)conducted an exclusive int...THE Hainan Free Trade Port(FTP)officially launched island-wide special customs operations on December 18,2025.One month in,a reporting team from China International Communications Group(CICG)conducted an exclusive interview with Feng Fei,secretary of the Hainan Provincial Committee of the Communist Party of China(CPC)and chairman of the Standing Committee of the Hainan Provincial People’s Congress.展开更多
Microorganisms are crucial for the breakdown of proteins and lipids in dry-fermented sausages and are intimately associated with the flavor profile of sausages.In this study,we used a mixed starter culture to ferment ...Microorganisms are crucial for the breakdown of proteins and lipids in dry-fermented sausages and are intimately associated with the flavor profile of sausages.In this study,we used a mixed starter culture to ferment sausages and investigated the flavor turnover.During the fermentation of salami,the data from free amino acids(FAAs),free fatty acids(FFAs)and volatile flavor substances were used to assess the quality of salami.At the end of fermentation,the total FAAs increased from 1171.32 to 4582.48 mg/kg in the control group and 5053.25 mg/kg in the experimental group.Additionally,following inoculation with the mixed starter culture,the levels of glutamic acid,lysine,methionine,valine and leucine were significantly higher(P<0.05)than those in the control group.Oleic acid(C_(18:1))and chondritic acid(C_(16:0))were the two most abundant FFAs in both salami samples with 45.86%and 26.07%on the 23^(th)day in mixed culture inoculated salami.The mixed starter inoculated group had significantly lower saturated fatty acids and higher percentage levels of monounsaturated fatty acids than the control group(P<0.05).In the volatile flavor substance analysis,a total of 61 volatile compounds were found.Ester compounds were progressively enriched with drying time,significantly increasing the flavor substances,like ethyl diphosgene,1-octen-3-ol,and 2,3-butanediol at P<0.05.The correlation analysis between the core flora and volatile flavor compounds during fermentation and maturation of salami indicates Lactobacillus sakei and Lactobacillus rhamnosus were significantly higher and positively correlated with the major volatile organic compounds,which are the key core microorganisms affecting the flavor quality of fermented sausages.展开更多
The Hainan FTP is a game changer,and those who seize the opportunities it offers early will be in an advantageous position As it provides a vital new model for China’s international trade and logistics,the Hainan Fre...The Hainan FTP is a game changer,and those who seize the opportunities it offers early will be in an advantageous position As it provides a vital new model for China’s international trade and logistics,the Hainan Free Trade Port(FTP)stands out among similar opening-up initiatives.展开更多
On December 18,2025, Hainan Free Trade Port (Hainan FTP) officially began islandwide special customs operations.Although only two months have passed since this landmark step, the shift is already visible everywhere—f...On December 18,2025, Hainan Free Trade Port (Hainan FTP) officially began islandwide special customs operations.Although only two months have passed since this landmark step, the shift is already visible everywhere—from the bustling flow of international passengers at Haikou Meilan International Airport to the steady stream of cargo vessels calling at Yangpu Port, and even in the sustained attention investors are paying to “Hainan-related” stocks.Together, these signals point to one clear conclusion:China’s largest special economic zone has entered a new phase of development.展开更多
The Hainan Free Trade Port (FTP) is a key step for China to advance high-standard opening-up and seize a more active role in economic globalization. After early trials, a policy framework has taken shape, and islandwi...The Hainan Free Trade Port (FTP) is a key step for China to advance high-standard opening-up and seize a more active role in economic globalization. After early trials, a policy framework has taken shape, and islandwide special customs operations mark a shift from design to full implementation.As of January 18, island-wide special customs operations in Hainan FTP had been in place for a month. The first month ran smoothly, with more efficient flow of goods, people, and capital.This reflects China’s institutional opening-up and, amid slowing global growth, has injected fresh vitality into the regional and global economy.展开更多
The Hainan FTP is a game changer and those who seize the opportunities it offers early will reap substantial benefits.AS it provides a vital new model for China’sinternational trade and logistics,theHainan Free Trade...The Hainan FTP is a game changer and those who seize the opportunities it offers early will reap substantial benefits.AS it provides a vital new model for China’sinternational trade and logistics,theHainan Free Trade Port(Hainan FTP)stands out from similar opening-up initiatives.展开更多
The Hainan Free Trade Port (FTP) officially launched island-wide special customs operations on December 18, 2025. One month in, a r eporting team from China International Communications Group (CICG)conducted an exclus...The Hainan Free Trade Port (FTP) officially launched island-wide special customs operations on December 18, 2025. One month in, a r eporting team from China International Communications Group (CICG)conducted an exclusive interview with Feng Fei, secretary of the Hainan Provincial Committee of the Communist Party of China (CPC) and chairman of the Standing Committee of the Hainan Provincial People’s Congress. Drawing on early results and the policy benefits already taking shape, Feng shared insights into Hainan’s core strengths,development potential, and the opportunities it offers to the world.展开更多
China launches island-wide special customs operations in Hainan FTP.China launched island-wide special customs operations in the Hainan Free Trade Port(FTP),the world’s largest FTP by area,on December 18,2025,allowin...China launches island-wide special customs operations in Hainan FTP.China launched island-wide special customs operations in the Hainan Free Trade Port(FTP),the world’s largest FTP by area,on December 18,2025,allowing freer entry of overseas goods,expanding zerotariff coverage,and introducing more business-friendly measures.展开更多
Preferential policies,efficient government,and a favorable geographical location...a multitude of factors make the Hainan FTP a promising land for businesses.SOON after the Hainan Free Trade Port(FTP)launched special ...Preferential policies,efficient government,and a favorable geographical location...a multitude of factors make the Hainan FTP a promising land for businesses.SOON after the Hainan Free Trade Port(FTP)launched special customs operations at the end of 2025,private enterprises operating at its Yangpu Port began to benefit substantially from the favorable policies and surging growth momentum in the region.While riding on an ocean of opportunities opened by the FTP,local businesses are bringing the island to a new level of prosperity,and thriving together with it as a community of shared future.展开更多
Hainan FTP will boost alignment with international rules in China’s opening up The Hainan Free Trade Port(FTP)represents a significant step forward in China’s pursuit of high-standard opening up and greater engageme...Hainan FTP will boost alignment with international rules in China’s opening up The Hainan Free Trade Port(FTP)represents a significant step forward in China’s pursuit of high-standard opening up and greater engagement in economic globalisation.Following years of exploration,the policy framework for the Hainan FTP has come into being,and the recent launch of island-wide special customs operations marks an important transition-from institutional design to full implementation.展开更多
The Double Take column looks at a single topic from an African and Chinese perspective.This month,we weigh the advantages of taking on debt against the benefits of staying debt-free.
The Hainan Free Trade Port(FTP),with the launching of island-wide special customs operations,is allowing greater convenience for overseas goods to enter the island,trying to build it into an efficient hub connecting C...The Hainan Free Trade Port(FTP),with the launching of island-wide special customs operations,is allowing greater convenience for overseas goods to enter the island,trying to build it into an efficient hub connecting China with the rest of the world.Its core appeal no longer relies solely on policy incentives but has shifted toward transparent and predictable institutional guarantees which provide stable expectations for global investors.展开更多
Activation pruning reduces neural network complexity by eliminating low-importance neuron activations,yet identifying the critical pruning threshold—beyond which accuracy rapidly deteriorates—remains computationally...Activation pruning reduces neural network complexity by eliminating low-importance neuron activations,yet identifying the critical pruning threshold—beyond which accuracy rapidly deteriorates—remains computationally expensive and typically requires exhaustive search.We introduce a thermodynamics-inspired framework that treats activation distributions as energy-filtered physical systems and employs the free energy of activations as a principled evaluation metric.Phase-transition-like phenomena in the free-energy profile—such as extrema,inflection points,and curvature changes—yield reliable estimates of the critical pruning threshold,providing a theoretically grounded means of predicting sharp accuracy degradation.To further enhance efficiency,we propose a renormalized free energy technique that approximates full-evaluation free energy using only the activation distribution of the unpruned network.This eliminates repeated forward passes,dramatically reducing computational overhead and achieving speedups of up to 550×for MLPs.Extensive experiments across diverse vision architectures(MLP,CNN,ResNet,MobileNet,Vision Transformer)and text models(LSTM,BERT,ELECTRA,T5,GPT-2)on multiple datasets validate the generality,robustness,and computational efficiency of our approach.Overall,this work establishes a theoretically grounded and practically effective framework for activation pruning,bridging the gap between analytical understanding and efficient deployment of sparse neural networks.展开更多
Plant-related organic compound(PROC) may interact with redox-active metals like iron while they are present in soil or aquatic environment, but their effects on the photoreduction of Fe(Ⅲ) remain largely unexplored. ...Plant-related organic compound(PROC) may interact with redox-active metals like iron while they are present in soil or aquatic environment, but their effects on the photoreduction of Fe(Ⅲ) remain largely unexplored. This study investigates the photochemical behavior of Fe(Ⅲ)-PROC complexes using alkaline lignin(AL), betaine hydrochloride(BH), and phytic acid(PA) as representative proxies for PROC. The reductive agent AL demonstrated the ability to directly reduce Fe(Ⅲ) to Fe(Ⅱ). In contrast, BH, being unable to form strong complexes with Fe(Ⅲ), was able to quench·OH, thereby resulting in a shift of the redox equilibrium towards Fe(Ⅱ). PA exhibited a strong binding affinity for Fe(Ⅲ), effectively inhibiting its photoreduction. Electron paramagnetic resonance(EPR) analysis, utilizing 5,5-dimethyl-1-pyrroline-N-oxide(DMPO) as a spin trap, revealed that the DMPO-OH signal detected in photolyzed Fe(Ⅲ)-PROC solutions originated from various pathways. Specifically, uncomplexed Fe(Ⅲ) in AL or BH solutions was shown to oxidize DMPO directly, leading to the formation of a false DMPO-OH adduct. The addition of ethanol to the photolyzed Fe(Ⅲ)-AL and Fe(Ⅲ)-BH systems resulted in the generation of the DMPO-CH(CH_(3))OH adduct, thereby confirming the presence of authentic·OH in these systems. The photolysis of the Fe(Ⅲ)-PA complex may proceed via a photodissociation mechanism, where the resulting loosely bound Fe(Ⅲ)can oxidize DMPO, followed by a nucleophilic attack from water. This research highlights the multifaceted roles of PROC in facilitating the redox cycling of iron within soil and aquatic ecosystems.展开更多
The advancement of integrated die-casting technology calls for high-strength,high-ductility heat-treatment-free Al alloys.This study investigates the use of a new AlSiFeMnVTiSrZr heat-treatment-free die-casting alloy ...The advancement of integrated die-casting technology calls for high-strength,high-ductility heat-treatment-free Al alloys.This study investigates the use of a new AlSiFeMnVTiSrZr heat-treatment-free die-casting alloy for shock tower manufacturing.Results show the alloy has excellent overall mechanical properties,but significant regional differences in microstructure and performance are found in the shock tower casting:Far-gate Position 6 has almost no externally solidified crystals(ESCs),whereas dense coarse dendritic ESCs exist in the center of near-gate Position 5.The fracture surface of Position 6 shows a steeper slope,while Position 5 has a rough crack propagation platform.Far-gate Position 6 also has higher porosity(nearly triple that of near-gate Region 5)and larger average pore size.Analysis reveals microstructural heterogeneity between near-and far-gate regions strongly influences mechanical performance.Notably,coarse dendritic ESCs in the near-gate region restrict grain boundary strengthening,leading to lower yield strength despite low porosity.Conversely,while fine grains in the far-gate region could enhance grain boundary strengthening,abundant porosity acts as crack initiation sites,severely reducing ductility.These findings provide theoretical guidance for evaluating integrated die-cast component performance.展开更多
We successfully incorporated phenyl groups into a small-molecule quaternary ammonium cross-linker and synthesized cross-linked polybenzimidazole membranes via a one-step cross-linking process.Compared with conventiona...We successfully incorporated phenyl groups into a small-molecule quaternary ammonium cross-linker and synthesized cross-linked polybenzimidazole membranes via a one-step cross-linking process.Compared with conventional quaternary ammonium-crosslinked benzimidazole membranes,the introduction of phenyl groups significantly increases the free volume within the membrane.After phosphoric acid doping,the benzimidazole membrane with larger free volume retains more phosphoric acid compared to conventional quaternary ammonium-crosslinked membranes,forming an extensive hydrogen-bonding network that effectively enhances its anhydrous proton conductivity.The anhydrous proton conductivity reaches 91 mS·cm^(-1)at 160℃,substantially higher than that of conventional quaternary ammonium-crosslinked membranes with the same mass fraction.Benefiting from the improved conductivity,the membrane electrode assembly exhibits reduced ohmic polarization,achieving a peak power density of 792 mW·cm^(-2)at 160℃.展开更多
Ion conduction in covalent-organic framework(COF)membranes is vital for energy conversion and storage.Conventional phenomenological methods based on the Arrhenius equation offer micrometer-scale cognition of ion condu...Ion conduction in covalent-organic framework(COF)membranes is vital for energy conversion and storage.Conventional phenomenological methods based on the Arrhenius equation offer micrometer-scale cognition of ion conduction,whereas they ignore atomic details of ion-pore interactions and sophisticated conduction mechanisms,leaving gaps in high-resolution and bottom-up understanding of ion conduction in a nanoconfined space.In this study,we develop a hierarchical approach by holistically synergizing electronic structure calculations,first-principles molecular dynamics simulations,and thermodynamic integration methods to investigate the conduction of chloride(Cl^(-))and hydroxide(OH^(-))ions in a COF membrane.It is revealed that Cl^(-)ion with symmetric charge distribution undergoes weak solvation and tight ion-pore binding,which results in a tortuous conduction pathway,a high energy barrier,and slow diffusion based on the vehicular mechanism.In remarkable contrast,OH^(-)ion with heterogeneous charge distribution features strong solvation and weak ion-pore binding,and it jumps frequently via a smooth pathway and a low energy barrier.Moreover,OH^(-)ion conduction follows a mixed vehicular and Grotthuss mechanism,causing highly mutable ion identity and number,as well as superior dynamics due to proton transfer.This hierarchical approach provides sub-nanometer resolution insights into ion conduction,guiding intelligent membrane design and performance regulation to control ion conduction for emerging applications.展开更多
文摘Even though theymight not haveenough food intheir own stom-achs,Tibetan peasantswould feed their draughtcattle with the best food,asthey depended on them forplowing. Such good treat-ment lasted until the ani-mals died,after which,some peasants would burythem in their own fields,
文摘Hainan is transforming into a world-class hub,with expanded free trade policies,robust infrastructure and global business opportunities The Hainan Free Trade Port(FTP)officially launched island-wide special customs operations on 18 December 2025.One month in,reporters from China International Communications Group(CICG)conducted an exclusive interview with Feng Fei,secretary of the Hainan Provincial Committee of the Communist Party of China(CPC)and chairman of the Standing Committee of the Hainan Provincial People’s Congress.
文摘The Hainan Free Trade Port’s implementation of special customs operations marks a significant stride in China’s institutional opening-up,spurring global trade and investment flows.THE Hainan Free Trade Port(FTP)represents a significant step forward in China’s pursuit of high-standard opening-up and greater engagement in economic globalization.
文摘THE Hainan Free Trade Port(FTP)officially launched island-wide special customs operations on December 18,2025.One month in,a reporting team from China International Communications Group(CICG)conducted an exclusive interview with Feng Fei,secretary of the Hainan Provincial Committee of the Communist Party of China(CPC)and chairman of the Standing Committee of the Hainan Provincial People’s Congress.
基金supported by the National Key Research and Development Program of China(2023YFD2100104)Henan Provincial Major Science and Technology Special Fund(231100110400).
文摘Microorganisms are crucial for the breakdown of proteins and lipids in dry-fermented sausages and are intimately associated with the flavor profile of sausages.In this study,we used a mixed starter culture to ferment sausages and investigated the flavor turnover.During the fermentation of salami,the data from free amino acids(FAAs),free fatty acids(FFAs)and volatile flavor substances were used to assess the quality of salami.At the end of fermentation,the total FAAs increased from 1171.32 to 4582.48 mg/kg in the control group and 5053.25 mg/kg in the experimental group.Additionally,following inoculation with the mixed starter culture,the levels of glutamic acid,lysine,methionine,valine and leucine were significantly higher(P<0.05)than those in the control group.Oleic acid(C_(18:1))and chondritic acid(C_(16:0))were the two most abundant FFAs in both salami samples with 45.86%and 26.07%on the 23^(th)day in mixed culture inoculated salami.The mixed starter inoculated group had significantly lower saturated fatty acids and higher percentage levels of monounsaturated fatty acids than the control group(P<0.05).In the volatile flavor substance analysis,a total of 61 volatile compounds were found.Ester compounds were progressively enriched with drying time,significantly increasing the flavor substances,like ethyl diphosgene,1-octen-3-ol,and 2,3-butanediol at P<0.05.The correlation analysis between the core flora and volatile flavor compounds during fermentation and maturation of salami indicates Lactobacillus sakei and Lactobacillus rhamnosus were significantly higher and positively correlated with the major volatile organic compounds,which are the key core microorganisms affecting the flavor quality of fermented sausages.
文摘The Hainan FTP is a game changer,and those who seize the opportunities it offers early will be in an advantageous position As it provides a vital new model for China’s international trade and logistics,the Hainan Free Trade Port(FTP)stands out among similar opening-up initiatives.
文摘On December 18,2025, Hainan Free Trade Port (Hainan FTP) officially began islandwide special customs operations.Although only two months have passed since this landmark step, the shift is already visible everywhere—from the bustling flow of international passengers at Haikou Meilan International Airport to the steady stream of cargo vessels calling at Yangpu Port, and even in the sustained attention investors are paying to “Hainan-related” stocks.Together, these signals point to one clear conclusion:China’s largest special economic zone has entered a new phase of development.
文摘The Hainan Free Trade Port (FTP) is a key step for China to advance high-standard opening-up and seize a more active role in economic globalization. After early trials, a policy framework has taken shape, and islandwide special customs operations mark a shift from design to full implementation.As of January 18, island-wide special customs operations in Hainan FTP had been in place for a month. The first month ran smoothly, with more efficient flow of goods, people, and capital.This reflects China’s institutional opening-up and, amid slowing global growth, has injected fresh vitality into the regional and global economy.
文摘The Hainan FTP is a game changer and those who seize the opportunities it offers early will reap substantial benefits.AS it provides a vital new model for China’sinternational trade and logistics,theHainan Free Trade Port(Hainan FTP)stands out from similar opening-up initiatives.
文摘The Hainan Free Trade Port (FTP) officially launched island-wide special customs operations on December 18, 2025. One month in, a r eporting team from China International Communications Group (CICG)conducted an exclusive interview with Feng Fei, secretary of the Hainan Provincial Committee of the Communist Party of China (CPC) and chairman of the Standing Committee of the Hainan Provincial People’s Congress. Drawing on early results and the policy benefits already taking shape, Feng shared insights into Hainan’s core strengths,development potential, and the opportunities it offers to the world.
文摘China launches island-wide special customs operations in Hainan FTP.China launched island-wide special customs operations in the Hainan Free Trade Port(FTP),the world’s largest FTP by area,on December 18,2025,allowing freer entry of overseas goods,expanding zerotariff coverage,and introducing more business-friendly measures.
文摘Preferential policies,efficient government,and a favorable geographical location...a multitude of factors make the Hainan FTP a promising land for businesses.SOON after the Hainan Free Trade Port(FTP)launched special customs operations at the end of 2025,private enterprises operating at its Yangpu Port began to benefit substantially from the favorable policies and surging growth momentum in the region.While riding on an ocean of opportunities opened by the FTP,local businesses are bringing the island to a new level of prosperity,and thriving together with it as a community of shared future.
文摘Hainan FTP will boost alignment with international rules in China’s opening up The Hainan Free Trade Port(FTP)represents a significant step forward in China’s pursuit of high-standard opening up and greater engagement in economic globalisation.Following years of exploration,the policy framework for the Hainan FTP has come into being,and the recent launch of island-wide special customs operations marks an important transition-from institutional design to full implementation.
文摘The Double Take column looks at a single topic from an African and Chinese perspective.This month,we weigh the advantages of taking on debt against the benefits of staying debt-free.
文摘The Hainan Free Trade Port(FTP),with the launching of island-wide special customs operations,is allowing greater convenience for overseas goods to enter the island,trying to build it into an efficient hub connecting China with the rest of the world.Its core appeal no longer relies solely on policy incentives but has shifted toward transparent and predictable institutional guarantees which provide stable expectations for global investors.
基金output of a research project implemented as part of the Basic Research Program at HSE University。
文摘Activation pruning reduces neural network complexity by eliminating low-importance neuron activations,yet identifying the critical pruning threshold—beyond which accuracy rapidly deteriorates—remains computationally expensive and typically requires exhaustive search.We introduce a thermodynamics-inspired framework that treats activation distributions as energy-filtered physical systems and employs the free energy of activations as a principled evaluation metric.Phase-transition-like phenomena in the free-energy profile—such as extrema,inflection points,and curvature changes—yield reliable estimates of the critical pruning threshold,providing a theoretically grounded means of predicting sharp accuracy degradation.To further enhance efficiency,we propose a renormalized free energy technique that approximates full-evaluation free energy using only the activation distribution of the unpruned network.This eliminates repeated forward passes,dramatically reducing computational overhead and achieving speedups of up to 550×for MLPs.Extensive experiments across diverse vision architectures(MLP,CNN,ResNet,MobileNet,Vision Transformer)and text models(LSTM,BERT,ELECTRA,T5,GPT-2)on multiple datasets validate the generality,robustness,and computational efficiency of our approach.Overall,this work establishes a theoretically grounded and practically effective framework for activation pruning,bridging the gap between analytical understanding and efficient deployment of sparse neural networks.
基金supported by the Natural Science Foundation of Shanghai(No.24ZR1419600).
文摘Plant-related organic compound(PROC) may interact with redox-active metals like iron while they are present in soil or aquatic environment, but their effects on the photoreduction of Fe(Ⅲ) remain largely unexplored. This study investigates the photochemical behavior of Fe(Ⅲ)-PROC complexes using alkaline lignin(AL), betaine hydrochloride(BH), and phytic acid(PA) as representative proxies for PROC. The reductive agent AL demonstrated the ability to directly reduce Fe(Ⅲ) to Fe(Ⅱ). In contrast, BH, being unable to form strong complexes with Fe(Ⅲ), was able to quench·OH, thereby resulting in a shift of the redox equilibrium towards Fe(Ⅱ). PA exhibited a strong binding affinity for Fe(Ⅲ), effectively inhibiting its photoreduction. Electron paramagnetic resonance(EPR) analysis, utilizing 5,5-dimethyl-1-pyrroline-N-oxide(DMPO) as a spin trap, revealed that the DMPO-OH signal detected in photolyzed Fe(Ⅲ)-PROC solutions originated from various pathways. Specifically, uncomplexed Fe(Ⅲ) in AL or BH solutions was shown to oxidize DMPO directly, leading to the formation of a false DMPO-OH adduct. The addition of ethanol to the photolyzed Fe(Ⅲ)-AL and Fe(Ⅲ)-BH systems resulted in the generation of the DMPO-CH(CH_(3))OH adduct, thereby confirming the presence of authentic·OH in these systems. The photolysis of the Fe(Ⅲ)-PA complex may proceed via a photodissociation mechanism, where the resulting loosely bound Fe(Ⅲ)can oxidize DMPO, followed by a nucleophilic attack from water. This research highlights the multifaceted roles of PROC in facilitating the redox cycling of iron within soil and aquatic ecosystems.
基金the National Natural Science Foundation of China(Grant Nos.52405342 and 52175335)the National Key Research and Development Program of China(Grant No.2022YFB3404201)+2 种基金the Fundamental Research Funds for the Central Universities(Grant Nos.N2302014 and N25ZJL003)the Natural Science Foundation Joint Foundation of Liaoning province(Grant No.2023-BSBA-108)the help provided by China FAW Foundry Co.,Ltd.
文摘The advancement of integrated die-casting technology calls for high-strength,high-ductility heat-treatment-free Al alloys.This study investigates the use of a new AlSiFeMnVTiSrZr heat-treatment-free die-casting alloy for shock tower manufacturing.Results show the alloy has excellent overall mechanical properties,but significant regional differences in microstructure and performance are found in the shock tower casting:Far-gate Position 6 has almost no externally solidified crystals(ESCs),whereas dense coarse dendritic ESCs exist in the center of near-gate Position 5.The fracture surface of Position 6 shows a steeper slope,while Position 5 has a rough crack propagation platform.Far-gate Position 6 also has higher porosity(nearly triple that of near-gate Region 5)and larger average pore size.Analysis reveals microstructural heterogeneity between near-and far-gate regions strongly influences mechanical performance.Notably,coarse dendritic ESCs in the near-gate region restrict grain boundary strengthening,leading to lower yield strength despite low porosity.Conversely,while fine grains in the far-gate region could enhance grain boundary strengthening,abundant porosity acts as crack initiation sites,severely reducing ductility.These findings provide theoretical guidance for evaluating integrated die-cast component performance.
基金Funded in part by the National Key Research and Development Program of China(No.2023YFB4006302)。
文摘We successfully incorporated phenyl groups into a small-molecule quaternary ammonium cross-linker and synthesized cross-linked polybenzimidazole membranes via a one-step cross-linking process.Compared with conventional quaternary ammonium-crosslinked benzimidazole membranes,the introduction of phenyl groups significantly increases the free volume within the membrane.After phosphoric acid doping,the benzimidazole membrane with larger free volume retains more phosphoric acid compared to conventional quaternary ammonium-crosslinked membranes,forming an extensive hydrogen-bonding network that effectively enhances its anhydrous proton conductivity.The anhydrous proton conductivity reaches 91 mS·cm^(-1)at 160℃,substantially higher than that of conventional quaternary ammonium-crosslinked membranes with the same mass fraction.Benefiting from the improved conductivity,the membrane electrode assembly exhibits reduced ohmic polarization,achieving a peak power density of 792 mW·cm^(-2)at 160℃.
基金supported by the National Science Foundation for Distinguished Young Scholars,China(No.52025065)the Key Research and Development Program of Shaanxi,China(No.2023GXLH-016)+3 种基金A*STAR LCER-FI,Singapore projects(LCERFI010015 U2102d2004 and LCERFI01-0033 U2102d2006)the National Research Foundation Singapore(NRF-CRP26-2021RS0002)the China Scholarship Council Program,China(Project ID:202306280178)for financial supportthe support of the Computing Center in Xi’an。
文摘Ion conduction in covalent-organic framework(COF)membranes is vital for energy conversion and storage.Conventional phenomenological methods based on the Arrhenius equation offer micrometer-scale cognition of ion conduction,whereas they ignore atomic details of ion-pore interactions and sophisticated conduction mechanisms,leaving gaps in high-resolution and bottom-up understanding of ion conduction in a nanoconfined space.In this study,we develop a hierarchical approach by holistically synergizing electronic structure calculations,first-principles molecular dynamics simulations,and thermodynamic integration methods to investigate the conduction of chloride(Cl^(-))and hydroxide(OH^(-))ions in a COF membrane.It is revealed that Cl^(-)ion with symmetric charge distribution undergoes weak solvation and tight ion-pore binding,which results in a tortuous conduction pathway,a high energy barrier,and slow diffusion based on the vehicular mechanism.In remarkable contrast,OH^(-)ion with heterogeneous charge distribution features strong solvation and weak ion-pore binding,and it jumps frequently via a smooth pathway and a low energy barrier.Moreover,OH^(-)ion conduction follows a mixed vehicular and Grotthuss mechanism,causing highly mutable ion identity and number,as well as superior dynamics due to proton transfer.This hierarchical approach provides sub-nanometer resolution insights into ion conduction,guiding intelligent membrane design and performance regulation to control ion conduction for emerging applications.
