Artificial intelligence(AI)is a strategic technology and an important driving force leading the scientific and technological revolution and industrial change.AI has the potential to enhance every technology as it rese...Artificial intelligence(AI)is a strategic technology and an important driving force leading the scientific and technological revolution and industrial change.AI has the potential to enhance every technology as it resembles enabling technologies like the combustion engine or electricity.We believe the nature of AI is interdisciplinary.In other words,the power of AI lies in augmenting its ability to accelerate research exponentially and the possibilities are endless.展开更多
Functional neurological recovery remains the primary objective when treating ischemic stroke.However,current therapeutic approaches often fall short of achieving optimal outcomes.One of the most significant challenges...Functional neurological recovery remains the primary objective when treating ischemic stroke.However,current therapeutic approaches often fall short of achieving optimal outcomes.One of the most significant challenges in stroke treatment is the effective delivery of neuroprotective agents across the blood–brain barrier to ischemic regions within the brain.The blood–brain barrier,while essential for protecting the brain from harmful substances,also restricts the passage of many therapeutic compounds,thus limiting their efficacy.In this review,we summarizes the emerging role of nanoparticle-based therapies for the treatment of ischemic stroke and investigate their potential to revolutionize drug delivery,enhance neuroprotection,and promote functional recovery.Recent advancements in nanotechnology have led to the development of engineered nanoparticles specifically designed to overcome the blood–brain barrier,thus enabling the targeted delivery of therapeutic agents directly to the affected brain areas.Preclinical studies have demonstrated the remarkable potential of nanoparticle-based therapies to activate key neuroprotective pathways,such as the phosphoinositide 3-kinase/protein kinase B/c AMP response element-binding protein signaling cascade,which is crucial for neuronal survival,synaptic plasticity,and post-stroke recovery.By modulating these pathways,nanoparticles could mitigate neuronal damage,reduce inflammation,and promote tissue repair.Furthermore,nanoparticles offer a unique advantage by enabling multimodal therapeutic strategies that simultaneously target multiple pathological mechanisms of ischemic stroke,including oxidative stress,neuroinflammation,and apoptosis.This multifaceted approach enhances the overall efficacy of treatment,addressing the complex and interconnected processes that contribute to stroke-related brain injury.Surface modifications,such as functionalization with specific ligands or targeting molecules,further improve the precision of drug delivery,enhance targeting specificity,and prolong systemic circulation,thereby optimizing therapeutic outcomes.Nanoparticlebased therapeutics represent a paradigm shift for the management of stroke and provide a promising avenue for reducing post-stroke disability and improving the outcomes of long-term rehabilitation.By combining targeted drug delivery with the ability to modulate critical neuroprotective pathways,nanoparticles hold the potential to transform the treatment landscape for ischemic stroke.However,while preclinical data are highly encouraging,significant challenges remain in translating these advancements into clinical practice.Further research is needed to refine nanoparticle designs,optimize their safety profiles,and ensure their scalability for widespread application.Rigorous clinical trials are essential to validate their efficacy,assess long-term biocompatibility,and address potential off-target effects.The integration of interdisciplinary approaches,combining insights from nanotechnology,neuroscience,and pharmacology,will be critical if we are to overcome these challenges.Ultimately,nanoparticle-based therapies offer a foundation for innovative,precision-based treatments that could significantly improve outcomes for stroke patients,thus paving the way for a new era in stroke care and neurological rehabilitation.展开更多
A multicenter study recently published introduced a novel prognostic model for predicting esophagogastric variceal rebleeding after endoscopic treatment in patients with cirrhosis.The model incorporated six readily av...A multicenter study recently published introduced a novel prognostic model for predicting esophagogastric variceal rebleeding after endoscopic treatment in patients with cirrhosis.The model incorporated six readily available clinical variables—albumin level,aspartate aminotransferase level,white blood cell count,ascites,portal vein thrombosis,and bleeding signs—and demonstrated promising predictive performance.However,limitations,including the retrospective design and exclusion of patients with hepatocellular carcinoma,may affect the generaliz-ability of the model.Additionally,further improvement is needed in the model’s discrimination between intermediate-and high-risk groups in external.Prospec-tive validation and inclusion of additional variables are recommended to enhan-ce predictive accuracy across diverse clinical scenarios.展开更多
Interaction between the Yangtze River and its tributaries in the Three Gorges Reservoir has an important influence on tributary algal blooms.Taking the Xiaojiang River as a typical tributary,a binary mixing model used...Interaction between the Yangtze River and its tributaries in the Three Gorges Reservoir has an important influence on tributary algal blooms.Taking the Xiaojiang River as a typical tributary,a binary mixing model used stable isotopes of hydrogen and oxygen to quantitatively analyze the water contribution and nutrient source structure of the tributary backwater area.Results showed that the isotope content(δD:−54.7‰,δ^(18)O−7.8‰)in the Yangtze River was higher than that in the tributaries(δD:−74.2‰,δ^(18)O−17.0‰)in the non-flood season and lower than that in the tributaries in the flood season.The Yangtze River contributed more than 50%water volume of the tributary backwater area in the non-flood season.The total nitrogen and total phosphorus concentrations in the backwater area were estimated based on water contribution ratio,and the results were in good agreement with the monitoring results.Load estimation showed that the nitrogen and phosphorus contribution ratio of the Yangtze River to the tributary backwater area was approximately 40%-80%in the non-flood season,and approximately 20%-40%in the flood season,on average.This study showed that the interaction between the Xiaojiang River and the Yangtze River is significant,and that Yangtze River recharge is an important source of nutrients in the Xiaojiang backwater area,which may play a driving role in Xiaojiang River algal blooms.展开更多
The Metal Stable Isotope Geochemistry Laboratory(MSIGL)at the University of Science and Technology of China has developed state-of-the-art analytical methods for twelve stable isotope systems,including Mg,Si,V,Fe,Cu,Z...The Metal Stable Isotope Geochemistry Laboratory(MSIGL)at the University of Science and Technology of China has developed state-of-the-art analytical methods for twelve stable isotope systems,including Mg,Si,V,Fe,Cu,Zn,Rb,Sr,Ag,Cd,Ba,and U.Geological and biological samples were first digested by acid dissolution or alkali dissolution.The target element was subsequently purified by the column chromatography method.A Neptune Plus MC-ICP-MS was used to measure isotope compositions and the isotope bias caused during measurements was calibrated by standard bracketing and/or the double spike method.The analytical procedure was carefully checked to ensure the high precision and accuracy of the data.Here,we summarized the protocol of these established methods and compiled the standard data measured at our lab as well as those reported in literature.This comprehensive dataset can serve as a reliable benchmark for calibration,method validation,and quality assurance in metal stable isotope analyses.展开更多
Large language models(LLMs)have significantly advanced artificial intelligence(AI)by excelling in tasks such as understanding,generation,and reasoning across multiple modalities.Despite these achievements,LLMs have in...Large language models(LLMs)have significantly advanced artificial intelligence(AI)by excelling in tasks such as understanding,generation,and reasoning across multiple modalities.Despite these achievements,LLMs have inherent limitations including outdated information,hallucinations,inefficiency,lack of interpretability,and challenges in domain-specific accuracy.To address these issues,this survey explores three promising directions in the post-LLM era:knowledge empowerment,model collaboration,and model co-evolution.First,we examine methods of integrating external knowledge into LLMs to enhance factual accuracy,reasoning capabilities,and interpretability,including incorporating knowledge into training objectives,instruction tuning,retrieval-augmented inference,and knowledge prompting.Second,we discuss model collaboration strategies that leverage the complementary strengths of LLMs and smaller models to improve efficiency and domain-specific performance through techniques such as model merging,functional model collaboration,and knowledge injection.Third,we delve into model co-evolution,in which multiple models collaboratively evolve by sharing knowledge,parameters,and learning strategies to adapt to dynamic environments and tasks,thereby enhancing their adaptability and continual learning.We illustrate how the integration of these techniques advances AI capabilities in science,engineering,and society—particularly in hypothesis development,problem formulation,problem-solving,and interpretability across various domains.We conclude by outlining future pathways for further advancement and applications.展开更多
Conjugated microporous polymers(CMPs)have attracted considerable attention as potential organic anode materials for sodium-ion batteries(SIBs)due to their flexible chemical structure,high porosity,environmental friend...Conjugated microporous polymers(CMPs)have attracted considerable attention as potential organic anode materials for sodium-ion batteries(SIBs)due to their flexible chemical structure,high porosity,environmental friendliness,and cost effectiveness.However,the inherent shortcomings of organic electrodes,such as low conductivity,high solubility in electrolyte,narrow material utilization,etc.,limit their further development.In this work,we successfully prepared a novel porous polyimide PPD containing multicarbonyl active centers via the polycondensation of pyromellitic dianhydride(PMDA)and2,6-diaminoanthraquinone(DAAQ).The stable conjugated structure and multiple redox centers give the polymer high reversible specific capacity(244.6 m Ah/g after 100 cycles at 100 m A/g),ultra-long cycle stability(100.7 m Ah/g after 2000 cycles at 1.0 A/g),and predominant rate capability.Meanwhile,the sodium storage mechanism of the electrode materials during the charging and discharging process is investigated by ex-situ XPS/FTIR analysis.Due to the exceptional electrochemical properties and simple synthesis method,this work may shed light on the preparation of polyimide-based anodes for high specific capacity and rate capability secondary batteries.展开更多
Cyclic changes in the internal pressure of compressed air energy storage reservoirs in abandoned coal mines result in complex alternating loads on the rocks surrounding the energy storage reservoirs.These complex alte...Cyclic changes in the internal pressure of compressed air energy storage reservoirs in abandoned coal mines result in complex alternating loads on the rocks surrounding the energy storage reservoirs.These complex alternating loads can be regarded as multi-stage constant-amplitude cyclic loads following simplification.In this paper,the mechanical responses and acoustic emission(AE)characteristics of red sandstone with five bedding dip angles(0°,30°,45°,60°,and 90°)under such loads are investigated,and the damage evolution processes of the five specimens are revealed from both quantitative and microscopic perspectives.The results show that the fatigue deformation characteristics of the specimens are affected by the bedding dip angle.Under cyclic loads,the axially irreversible plastic deformations of the rocks increase,their elastic stiffness increases,their crack volumetric strain increases and then decreases,and their AE cumulative count/energy curves exhibit a ladder shape.A damage evolution model based on the crack volumetric strain is proposed,and the damage evolution process is divided into two stages:a rapid increase stage and a tendency toward stabilization stage.Through cluster analysis,the AE events are used to classify the damage into three categories:small-sized localized damage,large-sized tensile damage,and large-sized shear damage.Finally,the MohreCoulomb criterion is applied to analyze the relationship between the failure modes of the red sandstone specimens and the dip angle of the bedding.The results of this study will help to predict the stability and safety of compressed air energy storage reservoirs in abandoned coal mines.展开更多
Salt cavern energy storage technology contributes to energy reserves and renewable energy scale-up.This study focuses on salt cavern gas storage in Jintan to assess the long-term stability of its surrounding rock unde...Salt cavern energy storage technology contributes to energy reserves and renewable energy scale-up.This study focuses on salt cavern gas storage in Jintan to assess the long-term stability of its surrounding rock under frequent operation.The fatigue test results indicate that stress holding significantly reduces fatigue life,with the magnitude of stress level outweighing the duration of holding time in determining peak strain.Employing a machine learning approach,the impact of various factors on fatigue life and peak strain was quantified,revealing that higher stress limits and stress holding adversely impact the fatigue index,whereas lower stress limits and rate exhibit a positive effect.A novel fatigue-creep composite damage constitutive model is constructed,which is able to consider stress magnitude,rate,and stress holding.The model,validated through multi-path tests,accurately captures the elasto-viscous behavior of salt rock during loading,unloading,and stress holding.Sensitivity analysis further reveals the time-and stress-dependent behavior of model parameters,clarifying that strain changes stem not only from stress variations but are also influenced by alterations in elasto-viscous parameters.This study provides a new method for the mechanical assessment of salt cavern gas storage surrounding rocks.展开更多
To ensure the safe implementation of underground reservoirs in abandoned coal mines,this study explores the mechanical behavior and failure mechanisms of coal-concrete composite structures under staged cyclic loading....To ensure the safe implementation of underground reservoirs in abandoned coal mines,this study explores the mechanical behavior and failure mechanisms of coal-concrete composite structures under staged cyclic loading.Specimens with coal-to-concrete height ratios ranging from 0.5:1 to 3:1 were tested,with damage evolution continuously monitored using acoustic emission techniques.Results indicate that while the peak strength of pure materials decreases by approximately 1 MPa under cyclic stress compared to uniaxial compression,composite specimens exhibit strength enhancements exceeding 5 MPa.However,the peak strength of composite specimens decreases with increasing coal height,from 30 MPa at CR0.5 to 20 MPa at CR3.0.The damage state was assessed using the dynamic elastic strain energy index and Felicity ratio,which revealed that composite specimens are more prone to early damage accumulation.Spatial acoustic emission localization further reveals distinct failure modes across specimens with varying height ratios.To elucidate these differences,interfacial effects were incorporated into a modified twin-shear unified strength theory.The refined model accurately predicts the internal strength distribution and failure characteristics of the composite structures.These findings provide a theoretical basis for the structural design and safe operation of underground reservoir dams.展开更多
Implicit large-eddy simulation of an over-expanded screeching rectangular jet is performed with a seventh-order finite difference scheme.Good agreement is found between the predicted flow-and acoustic fields with the ...Implicit large-eddy simulation of an over-expanded screeching rectangular jet is performed with a seventh-order finite difference scheme.Good agreement is found between the predicted flow-and acoustic fields with the experimental observations.Fourier decomposition,phase-averaging analysis and Spectral Proper Orthogonal Decomposition(SPOD)are used to investigate the origin of the screech,the shock leakage during the shear-layer flapping,and the distinguishing fluctuating characteristics in the minor-and major-axis plane of the rectangular jet.It finds that the screech is radiated from the end of the forth shock cell,where the interaction of the shock waves with the shear layer causes periodic leakages of shock-wave tips in the minor-axis plane,resulting in the generation of intense acoustic waves in the surrounding air.An obvious flapping mode at the same frequency of the screech is captured in the minor-axis plane and dominates the dynamic motions of the rectangular jet.The SPOD modes of pressure and velocity fluctuations at the screech frequency help to reveal the relationship between the screech generation and the coherent structures.展开更多
It has been widely recognized that hole transporting materials(HTMs)play a key role in the rapid progress of perovskite solar cells(PVSCs).However,common organic HTMs such as spiro-OMe TAD not only suffer from high sy...It has been widely recognized that hole transporting materials(HTMs)play a key role in the rapid progress of perovskite solar cells(PVSCs).However,common organic HTMs such as spiro-OMe TAD not only suffer from high synthetic costs,but also usually require the additional chemical doping process to improve their hole transport ability,which unfortunately induces the terrible stability issue.Therefore,it is urgent to develop low-cost dopant-free HTMs for efficient and stable PVSCs.In this work,we have successfully developed a new class of efficient dopant-free fluoranthene-based HTMs(TPF1–5)with quite low lab synthetic costs by combining donor-acceptor and branched structure designs.The detailed structure-property study revealed that tuning the twisted arms at different substitution sites would regulate the intermolecular interactions and film-forming ability,thereby significantly affecting the performance of the HTMs.By applying these HTMs in conventional PVSCs,the dopant-free TPF1-based devices not only achieved the best efficiency of 21.76%,which is comparable to that of the doped spiro-OMeTAD control devices,but also showed much better operational stability,which maintained over 87%of the initial efficiency under maximum power point tracking after 1038 h.展开更多
The Gaoligong Mountains(GLGM),located in southwestern China,extend north to south along the western border of the Hengduan Mountains,spanning approximately 600 km.In this study,we consolidated findings from 17 bird su...The Gaoligong Mountains(GLGM),located in southwestern China,extend north to south along the western border of the Hengduan Mountains,spanning approximately 600 km.In this study,we consolidated findings from 17 bird surveys conducted in the GLGM between 2010 and 2022.We found that the GLGM harbors tremendous bird diversity,with a total of 796 documented bird species in the region.Nearly a quarter(23.0%)of these species are listed as state key protected species or as Chinese and global threatened species.Analysis of species richness at the county level showed a decreasing trend with increasing latitude,with the greatest diversity in Yingjiang(661 species).Observations indicated that the GLGM belongs to the Oriental realm,primarily composed of bird species from southern and southwestern China.The GLGM plays an important role in avian conservation by sheltering exceptional bird diversity,providing corridors and flyways for bird migration and dispersal,and mitigating the effects of climate change.In response to the conservation needs of birds and other wildlife,the Chinese government has established numerous protected areas within the GLGM.Despite these efforts,avian conservation still faces considerable challenges in the GLGM due to limitations in the protected area network,transboundary nature of the regions,and existing gaps in monitoring and research.展开更多
Fractal theory offers a powerful tool for the precise description and quantification of the complex pore structures in reservoir rocks,crucial for understanding the storage and migration characteristics of media withi...Fractal theory offers a powerful tool for the precise description and quantification of the complex pore structures in reservoir rocks,crucial for understanding the storage and migration characteristics of media within these rocks.Faced with the challenge of calculating the three-dimensional fractal dimensions of rock porosity,this study proposes an innovative computational process that directly calculates the three-dimensional fractal dimensions from a geometric perspective.By employing a composite denoising approach that integrates Fourier transform(FT)and wavelet transform(WT),coupled with multimodal pore extraction techniques such as threshold segmentation,top-hat transformation,and membrane enhancement,we successfully crafted accurate digital rock models.The improved box-counting method was then applied to analyze the voxel data of these digital rocks,accurately calculating the fractal dimensions of the rock pore distribution.Further numerical simulations of permeability experiments were conducted to explore the physical correlations between the rock pore fractal dimensions,porosity,and absolute permeability.The results reveal that rocks with higher fractal dimensions exhibit more complex pore connectivity pathways and a wider,more uneven pore distribution,suggesting that the ideal rock samples should possess lower fractal dimensions and higher effective porosity rates to achieve optimal fluid transmission properties.The methodology and conclusions of this study provide new tools and insights for the quantitative analysis of complex pores in rocks and contribute to the exploration of the fractal transport properties of media within rocks.展开更多
Although the performance of perovskite solar cells(PSCs)has been dramatically increased in recent years,stability is still the main obstacle preventing the PSCs from being commercial.PSC device instability can be caus...Although the performance of perovskite solar cells(PSCs)has been dramatically increased in recent years,stability is still the main obstacle preventing the PSCs from being commercial.PSC device instability can be caused by a variety of reasons,including ions diffusion,surface and grain boundary defects,etc.In this work,the cross-linkable tannic acid(TA)is introduced to modify perovskite film through post-treatment method.The numerous organic functional groups(–OH and C=O)in TA can interact with the uncoordinated Pb^(2+)and I^(-)ions in perovskite,thus passivating defects and inhibiting ions diffusion.In addition,the formed TA network can absorb a small amount of the residual moisture inside the device to protect the perovskite layer.Furthermore,TA modification regulates the energy level of perovskite,and reduces interfacial charge recombination.Ultimately,following TA treatment,the device efficiency is increased significantly from 21.31%to 23.11%,with a decreased hysteresis effect.Notably,the treated device shows excellent air,thermal,and operational stability.In light of this,the readily available,inexpensive TA has the potential to operate as a multipurpose interfacial modifier to increase device efficiency while also enhancing device stability.展开更多
Artificial intelligence(AI)has emerged as a transformative force with the potential to positively impact every facet of society.One of its most profound applications lies in its ability to empower individuals within c...Artificial intelligence(AI)has emerged as a transformative force with the potential to positively impact every facet of society.One of its most profound applications lies in its ability to empower individuals within communities by leveraging their strengths,promoting independence,and aiding them in achieving their goals.Human uses for AI have grown across every aspect of society;from language generation to molecular synthesis,AI has begun to permeate every aspect of our lives.展开更多
The low-cost RFID tags have very limited computing and storage resources and this makes it difficult to completely solve their security and privacy problems. Lightweight authentication is considered as one of the most...The low-cost RFID tags have very limited computing and storage resources and this makes it difficult to completely solve their security and privacy problems. Lightweight authentication is considered as one of the most effective methods to ensure the security in the RFID system. Many light-weight authentication protocols use Hash function and pseudorandom generator to ensure the anonymity and confidential communication of the RFID system. But these protocols do not provide such security as they claimed. By analyzing some typical Hash-based RFID authentication protocols, it is found that they are vulnerable to some common attacks. Many protocols cannot resist tracing attack and de-synchronization attack. Some protocols cannot provide forward security. Gy?z? Gódor and Sándor Imre proposed a Hash-based authentication protocol and they claimed their protocol could resist the well-known attacks. But by constructing some different attack scenarios, their protocol is shown to be vulnerable to tracing attack and de-synchronization attack. Based on the analysis for the Hash-based authentication protocols, some feasible suggestions are proposed to improve the security of the RFID authentication protocols.展开更多
文摘Artificial intelligence(AI)is a strategic technology and an important driving force leading the scientific and technological revolution and industrial change.AI has the potential to enhance every technology as it resembles enabling technologies like the combustion engine or electricity.We believe the nature of AI is interdisciplinary.In other words,the power of AI lies in augmenting its ability to accelerate research exponentially and the possibilities are endless.
基金supported by the National Natural Science Foundations of China,Nos.82272163,82472164(both MF)。
文摘Functional neurological recovery remains the primary objective when treating ischemic stroke.However,current therapeutic approaches often fall short of achieving optimal outcomes.One of the most significant challenges in stroke treatment is the effective delivery of neuroprotective agents across the blood–brain barrier to ischemic regions within the brain.The blood–brain barrier,while essential for protecting the brain from harmful substances,also restricts the passage of many therapeutic compounds,thus limiting their efficacy.In this review,we summarizes the emerging role of nanoparticle-based therapies for the treatment of ischemic stroke and investigate their potential to revolutionize drug delivery,enhance neuroprotection,and promote functional recovery.Recent advancements in nanotechnology have led to the development of engineered nanoparticles specifically designed to overcome the blood–brain barrier,thus enabling the targeted delivery of therapeutic agents directly to the affected brain areas.Preclinical studies have demonstrated the remarkable potential of nanoparticle-based therapies to activate key neuroprotective pathways,such as the phosphoinositide 3-kinase/protein kinase B/c AMP response element-binding protein signaling cascade,which is crucial for neuronal survival,synaptic plasticity,and post-stroke recovery.By modulating these pathways,nanoparticles could mitigate neuronal damage,reduce inflammation,and promote tissue repair.Furthermore,nanoparticles offer a unique advantage by enabling multimodal therapeutic strategies that simultaneously target multiple pathological mechanisms of ischemic stroke,including oxidative stress,neuroinflammation,and apoptosis.This multifaceted approach enhances the overall efficacy of treatment,addressing the complex and interconnected processes that contribute to stroke-related brain injury.Surface modifications,such as functionalization with specific ligands or targeting molecules,further improve the precision of drug delivery,enhance targeting specificity,and prolong systemic circulation,thereby optimizing therapeutic outcomes.Nanoparticlebased therapeutics represent a paradigm shift for the management of stroke and provide a promising avenue for reducing post-stroke disability and improving the outcomes of long-term rehabilitation.By combining targeted drug delivery with the ability to modulate critical neuroprotective pathways,nanoparticles hold the potential to transform the treatment landscape for ischemic stroke.However,while preclinical data are highly encouraging,significant challenges remain in translating these advancements into clinical practice.Further research is needed to refine nanoparticle designs,optimize their safety profiles,and ensure their scalability for widespread application.Rigorous clinical trials are essential to validate their efficacy,assess long-term biocompatibility,and address potential off-target effects.The integration of interdisciplinary approaches,combining insights from nanotechnology,neuroscience,and pharmacology,will be critical if we are to overcome these challenges.Ultimately,nanoparticle-based therapies offer a foundation for innovative,precision-based treatments that could significantly improve outcomes for stroke patients,thus paving the way for a new era in stroke care and neurological rehabilitation.
文摘A multicenter study recently published introduced a novel prognostic model for predicting esophagogastric variceal rebleeding after endoscopic treatment in patients with cirrhosis.The model incorporated six readily available clinical variables—albumin level,aspartate aminotransferase level,white blood cell count,ascites,portal vein thrombosis,and bleeding signs—and demonstrated promising predictive performance.However,limitations,including the retrospective design and exclusion of patients with hepatocellular carcinoma,may affect the generaliz-ability of the model.Additionally,further improvement is needed in the model’s discrimination between intermediate-and high-risk groups in external.Prospec-tive validation and inclusion of additional variables are recommended to enhan-ce predictive accuracy across diverse clinical scenarios.
基金supported by the National Natural Science Foundation of China(No.U2040210).
文摘Interaction between the Yangtze River and its tributaries in the Three Gorges Reservoir has an important influence on tributary algal blooms.Taking the Xiaojiang River as a typical tributary,a binary mixing model used stable isotopes of hydrogen and oxygen to quantitatively analyze the water contribution and nutrient source structure of the tributary backwater area.Results showed that the isotope content(δD:−54.7‰,δ^(18)O−7.8‰)in the Yangtze River was higher than that in the tributaries(δD:−74.2‰,δ^(18)O−17.0‰)in the non-flood season and lower than that in the tributaries in the flood season.The Yangtze River contributed more than 50%water volume of the tributary backwater area in the non-flood season.The total nitrogen and total phosphorus concentrations in the backwater area were estimated based on water contribution ratio,and the results were in good agreement with the monitoring results.Load estimation showed that the nitrogen and phosphorus contribution ratio of the Yangtze River to the tributary backwater area was approximately 40%-80%in the non-flood season,and approximately 20%-40%in the flood season,on average.This study showed that the interaction between the Xiaojiang River and the Yangtze River is significant,and that Yangtze River recharge is an important source of nutrients in the Xiaojiang backwater area,which may play a driving role in Xiaojiang River algal blooms.
基金the National Science Foundation of China(Nos.42273007 and 42473008)the Distinguished Young Scholars of Anhui,China(No.2408085J021)。
文摘The Metal Stable Isotope Geochemistry Laboratory(MSIGL)at the University of Science and Technology of China has developed state-of-the-art analytical methods for twelve stable isotope systems,including Mg,Si,V,Fe,Cu,Zn,Rb,Sr,Ag,Cd,Ba,and U.Geological and biological samples were first digested by acid dissolution or alkali dissolution.The target element was subsequently purified by the column chromatography method.A Neptune Plus MC-ICP-MS was used to measure isotope compositions and the isotope bias caused during measurements was calibrated by standard bracketing and/or the double spike method.The analytical procedure was carefully checked to ensure the high precision and accuracy of the data.Here,we summarized the protocol of these established methods and compiled the standard data measured at our lab as well as those reported in literature.This comprehensive dataset can serve as a reliable benchmark for calibration,method validation,and quality assurance in metal stable isotope analyses.
基金supported in part by National Natural Science Foundation of China(62441605)。
文摘Large language models(LLMs)have significantly advanced artificial intelligence(AI)by excelling in tasks such as understanding,generation,and reasoning across multiple modalities.Despite these achievements,LLMs have inherent limitations including outdated information,hallucinations,inefficiency,lack of interpretability,and challenges in domain-specific accuracy.To address these issues,this survey explores three promising directions in the post-LLM era:knowledge empowerment,model collaboration,and model co-evolution.First,we examine methods of integrating external knowledge into LLMs to enhance factual accuracy,reasoning capabilities,and interpretability,including incorporating knowledge into training objectives,instruction tuning,retrieval-augmented inference,and knowledge prompting.Second,we discuss model collaboration strategies that leverage the complementary strengths of LLMs and smaller models to improve efficiency and domain-specific performance through techniques such as model merging,functional model collaboration,and knowledge injection.Third,we delve into model co-evolution,in which multiple models collaboratively evolve by sharing knowledge,parameters,and learning strategies to adapt to dynamic environments and tasks,thereby enhancing their adaptability and continual learning.We illustrate how the integration of these techniques advances AI capabilities in science,engineering,and society—particularly in hypothesis development,problem formulation,problem-solving,and interpretability across various domains.We conclude by outlining future pathways for further advancement and applications.
基金supported by National Natural Science Foundation,China(Nos.52071132,U21A20284 and 52261135632)Natural Science Foundation of Henan,China(Nos.232300421080,242300421035)+2 种基金Program for Innovative Team(in Science and Technology)in University of Henan Province,China(No.24IRTSTHN006)Key Scientific Research Programs in Universities of Henan Province,China–Special Projects for Basic Research(No.23ZX008)the Natural Science Foundation of Hunan Province,China(No.2023JJ50287)。
文摘Conjugated microporous polymers(CMPs)have attracted considerable attention as potential organic anode materials for sodium-ion batteries(SIBs)due to their flexible chemical structure,high porosity,environmental friendliness,and cost effectiveness.However,the inherent shortcomings of organic electrodes,such as low conductivity,high solubility in electrolyte,narrow material utilization,etc.,limit their further development.In this work,we successfully prepared a novel porous polyimide PPD containing multicarbonyl active centers via the polycondensation of pyromellitic dianhydride(PMDA)and2,6-diaminoanthraquinone(DAAQ).The stable conjugated structure and multiple redox centers give the polymer high reversible specific capacity(244.6 m Ah/g after 100 cycles at 100 m A/g),ultra-long cycle stability(100.7 m Ah/g after 2000 cycles at 1.0 A/g),and predominant rate capability.Meanwhile,the sodium storage mechanism of the electrode materials during the charging and discharging process is investigated by ex-situ XPS/FTIR analysis.Due to the exceptional electrochemical properties and simple synthesis method,this work may shed light on the preparation of polyimide-based anodes for high specific capacity and rate capability secondary batteries.
基金supported by the National Natural Science Foundation of China(Grant No.52374078)the Fundamental Research Funds for the Central Universities(Grant No.2023CDJKYJH021)the Sichuan-Chongqing Science and Technology Innovation Cooperation Program Project(Grant No.2024TIAD-CYKJCXX0011).
文摘Cyclic changes in the internal pressure of compressed air energy storage reservoirs in abandoned coal mines result in complex alternating loads on the rocks surrounding the energy storage reservoirs.These complex alternating loads can be regarded as multi-stage constant-amplitude cyclic loads following simplification.In this paper,the mechanical responses and acoustic emission(AE)characteristics of red sandstone with five bedding dip angles(0°,30°,45°,60°,and 90°)under such loads are investigated,and the damage evolution processes of the five specimens are revealed from both quantitative and microscopic perspectives.The results show that the fatigue deformation characteristics of the specimens are affected by the bedding dip angle.Under cyclic loads,the axially irreversible plastic deformations of the rocks increase,their elastic stiffness increases,their crack volumetric strain increases and then decreases,and their AE cumulative count/energy curves exhibit a ladder shape.A damage evolution model based on the crack volumetric strain is proposed,and the damage evolution process is divided into two stages:a rapid increase stage and a tendency toward stabilization stage.Through cluster analysis,the AE events are used to classify the damage into three categories:small-sized localized damage,large-sized tensile damage,and large-sized shear damage.Finally,the MohreCoulomb criterion is applied to analyze the relationship between the failure modes of the red sandstone specimens and the dip angle of the bedding.The results of this study will help to predict the stability and safety of compressed air energy storage reservoirs in abandoned coal mines.
基金supported by the National Natural Science Foundation of China(Nos.52374078,U24A20616 and 52074043)the Sichuan-Chongqing Science and Technology Innovation Cooperation Program Project(No.2024TIAD-CYKJCXX0011)the Fundamental Research Funds for the Central Universities(No.2023CDJKYJH021)。
文摘Salt cavern energy storage technology contributes to energy reserves and renewable energy scale-up.This study focuses on salt cavern gas storage in Jintan to assess the long-term stability of its surrounding rock under frequent operation.The fatigue test results indicate that stress holding significantly reduces fatigue life,with the magnitude of stress level outweighing the duration of holding time in determining peak strain.Employing a machine learning approach,the impact of various factors on fatigue life and peak strain was quantified,revealing that higher stress limits and stress holding adversely impact the fatigue index,whereas lower stress limits and rate exhibit a positive effect.A novel fatigue-creep composite damage constitutive model is constructed,which is able to consider stress magnitude,rate,and stress holding.The model,validated through multi-path tests,accurately captures the elasto-viscous behavior of salt rock during loading,unloading,and stress holding.Sensitivity analysis further reveals the time-and stress-dependent behavior of model parameters,clarifying that strain changes stem not only from stress variations but are also influenced by alterations in elasto-viscous parameters.This study provides a new method for the mechanical assessment of salt cavern gas storage surrounding rocks.
基金supported by the Deep Earth Probe and Mineral Resources Exploration-National Science and Technology Major Project(No.2024ZD1003903)National Natural Science Foundation of China(Nos.52374078,U24A20616,and 52074043)+1 种基金Sichuan-Chongqing Science and Technology Project Innovation Cooperation Program(No.2024TIAD-CYKJCXX0011)the Fundamental Research Funds for the Central Universities(No.2023CDJKYJH021).
文摘To ensure the safe implementation of underground reservoirs in abandoned coal mines,this study explores the mechanical behavior and failure mechanisms of coal-concrete composite structures under staged cyclic loading.Specimens with coal-to-concrete height ratios ranging from 0.5:1 to 3:1 were tested,with damage evolution continuously monitored using acoustic emission techniques.Results indicate that while the peak strength of pure materials decreases by approximately 1 MPa under cyclic stress compared to uniaxial compression,composite specimens exhibit strength enhancements exceeding 5 MPa.However,the peak strength of composite specimens decreases with increasing coal height,from 30 MPa at CR0.5 to 20 MPa at CR3.0.The damage state was assessed using the dynamic elastic strain energy index and Felicity ratio,which revealed that composite specimens are more prone to early damage accumulation.Spatial acoustic emission localization further reveals distinct failure modes across specimens with varying height ratios.To elucidate these differences,interfacial effects were incorporated into a modified twin-shear unified strength theory.The refined model accurately predicts the internal strength distribution and failure characteristics of the composite structures.These findings provide a theoretical basis for the structural design and safe operation of underground reservoir dams.
基金support of the National Natural Science Foundation of China(No.12372221)is acknowledged。
文摘Implicit large-eddy simulation of an over-expanded screeching rectangular jet is performed with a seventh-order finite difference scheme.Good agreement is found between the predicted flow-and acoustic fields with the experimental observations.Fourier decomposition,phase-averaging analysis and Spectral Proper Orthogonal Decomposition(SPOD)are used to investigate the origin of the screech,the shock leakage during the shear-layer flapping,and the distinguishing fluctuating characteristics in the minor-and major-axis plane of the rectangular jet.It finds that the screech is radiated from the end of the forth shock cell,where the interaction of the shock waves with the shear layer causes periodic leakages of shock-wave tips in the minor-axis plane,resulting in the generation of intense acoustic waves in the surrounding air.An obvious flapping mode at the same frequency of the screech is captured in the minor-axis plane and dominates the dynamic motions of the rectangular jet.The SPOD modes of pressure and velocity fluctuations at the screech frequency help to reveal the relationship between the screech generation and the coherent structures.
基金supported by National Key Research&Development Program of China(No.2023YFE0210900)National Natural Science Foundation of China(No.21975085)+1 种基金Excellent Youth Foundation of Hubei Scientific Committee(No.2021CFA065)open Fund of Hubei Key Laboratory of Material Chemistry and Service Failure(No.2023MCF02)。
文摘It has been widely recognized that hole transporting materials(HTMs)play a key role in the rapid progress of perovskite solar cells(PVSCs).However,common organic HTMs such as spiro-OMe TAD not only suffer from high synthetic costs,but also usually require the additional chemical doping process to improve their hole transport ability,which unfortunately induces the terrible stability issue.Therefore,it is urgent to develop low-cost dopant-free HTMs for efficient and stable PVSCs.In this work,we have successfully developed a new class of efficient dopant-free fluoranthene-based HTMs(TPF1–5)with quite low lab synthetic costs by combining donor-acceptor and branched structure designs.The detailed structure-property study revealed that tuning the twisted arms at different substitution sites would regulate the intermolecular interactions and film-forming ability,thereby significantly affecting the performance of the HTMs.By applying these HTMs in conventional PVSCs,the dopant-free TPF1-based devices not only achieved the best efficiency of 21.76%,which is comparable to that of the doped spiro-OMeTAD control devices,but also showed much better operational stability,which maintained over 87%of the initial efficiency under maximum power point tracking after 1038 h.
基金supported by the National Key R&D Program of China(2022YFC2602500,2022YFC2602502)Biodiversity Survey and Assessment Project of the Ministry of Ecology and Environment,China,Second Xizang Plateau Scientific Expedition and Research Program(STEP,2019QZKK0501)+3 种基金Major Science and Technique Programs in Yunnan Province(202102AA310055)National Natural Science Foundation of China(32070435)Science and Technology Basic Resources Investigation Program of China“Wild germplasm collection and preservation in Great Gaoligong Mountain”(2021FY100200)Project for Talent and Platform of Science and Technology in Yunnan Province Science and Technology Department(202205AM070007)。
文摘The Gaoligong Mountains(GLGM),located in southwestern China,extend north to south along the western border of the Hengduan Mountains,spanning approximately 600 km.In this study,we consolidated findings from 17 bird surveys conducted in the GLGM between 2010 and 2022.We found that the GLGM harbors tremendous bird diversity,with a total of 796 documented bird species in the region.Nearly a quarter(23.0%)of these species are listed as state key protected species or as Chinese and global threatened species.Analysis of species richness at the county level showed a decreasing trend with increasing latitude,with the greatest diversity in Yingjiang(661 species).Observations indicated that the GLGM belongs to the Oriental realm,primarily composed of bird species from southern and southwestern China.The GLGM plays an important role in avian conservation by sheltering exceptional bird diversity,providing corridors and flyways for bird migration and dispersal,and mitigating the effects of climate change.In response to the conservation needs of birds and other wildlife,the Chinese government has established numerous protected areas within the GLGM.Despite these efforts,avian conservation still faces considerable challenges in the GLGM due to limitations in the protected area network,transboundary nature of the regions,and existing gaps in monitoring and research.
基金supported by the National Natural Science Foundation of China (Nos.52374078 and 52074043)the Fundamental Research Funds for the Central Universities (No.2023CDJKYJH021)。
文摘Fractal theory offers a powerful tool for the precise description and quantification of the complex pore structures in reservoir rocks,crucial for understanding the storage and migration characteristics of media within these rocks.Faced with the challenge of calculating the three-dimensional fractal dimensions of rock porosity,this study proposes an innovative computational process that directly calculates the three-dimensional fractal dimensions from a geometric perspective.By employing a composite denoising approach that integrates Fourier transform(FT)and wavelet transform(WT),coupled with multimodal pore extraction techniques such as threshold segmentation,top-hat transformation,and membrane enhancement,we successfully crafted accurate digital rock models.The improved box-counting method was then applied to analyze the voxel data of these digital rocks,accurately calculating the fractal dimensions of the rock pore distribution.Further numerical simulations of permeability experiments were conducted to explore the physical correlations between the rock pore fractal dimensions,porosity,and absolute permeability.The results reveal that rocks with higher fractal dimensions exhibit more complex pore connectivity pathways and a wider,more uneven pore distribution,suggesting that the ideal rock samples should possess lower fractal dimensions and higher effective porosity rates to achieve optimal fluid transmission properties.The methodology and conclusions of this study provide new tools and insights for the quantitative analysis of complex pores in rocks and contribute to the exploration of the fractal transport properties of media within rocks.
基金supported by the General Program of Chongqing Natural Science Foundation(CSTB2022NSCQMSX1227 and CSTB2022NSCQ-MSX0459)the supports from the Fundamental Research Funds for the Central Universities(SWU-XDJH202314)。
文摘Although the performance of perovskite solar cells(PSCs)has been dramatically increased in recent years,stability is still the main obstacle preventing the PSCs from being commercial.PSC device instability can be caused by a variety of reasons,including ions diffusion,surface and grain boundary defects,etc.In this work,the cross-linkable tannic acid(TA)is introduced to modify perovskite film through post-treatment method.The numerous organic functional groups(–OH and C=O)in TA can interact with the uncoordinated Pb^(2+)and I^(-)ions in perovskite,thus passivating defects and inhibiting ions diffusion.In addition,the formed TA network can absorb a small amount of the residual moisture inside the device to protect the perovskite layer.Furthermore,TA modification regulates the energy level of perovskite,and reduces interfacial charge recombination.Ultimately,following TA treatment,the device efficiency is increased significantly from 21.31%to 23.11%,with a decreased hysteresis effect.Notably,the treated device shows excellent air,thermal,and operational stability.In light of this,the readily available,inexpensive TA has the potential to operate as a multipurpose interfacial modifier to increase device efficiency while also enhancing device stability.
文摘Artificial intelligence(AI)has emerged as a transformative force with the potential to positively impact every facet of society.One of its most profound applications lies in its ability to empower individuals within communities by leveraging their strengths,promoting independence,and aiding them in achieving their goals.Human uses for AI have grown across every aspect of society;from language generation to molecular synthesis,AI has begun to permeate every aspect of our lives.
文摘The low-cost RFID tags have very limited computing and storage resources and this makes it difficult to completely solve their security and privacy problems. Lightweight authentication is considered as one of the most effective methods to ensure the security in the RFID system. Many light-weight authentication protocols use Hash function and pseudorandom generator to ensure the anonymity and confidential communication of the RFID system. But these protocols do not provide such security as they claimed. By analyzing some typical Hash-based RFID authentication protocols, it is found that they are vulnerable to some common attacks. Many protocols cannot resist tracing attack and de-synchronization attack. Some protocols cannot provide forward security. Gy?z? Gódor and Sándor Imre proposed a Hash-based authentication protocol and they claimed their protocol could resist the well-known attacks. But by constructing some different attack scenarios, their protocol is shown to be vulnerable to tracing attack and de-synchronization attack. Based on the analysis for the Hash-based authentication protocols, some feasible suggestions are proposed to improve the security of the RFID authentication protocols.
