The Editor-in-Chief has retracted this article.Following this publication,concerns were raised regarding the similarity of images presented in this article with previously published articles[1,2].The authors were unab...The Editor-in-Chief has retracted this article.Following this publication,concerns were raised regarding the similarity of images presented in this article with previously published articles[1,2].The authors were unable to provide a satisfactory explanation and raw data for the concerns upon request.展开更多
The gas kick represents a major risk in deepwater oil and gas exploration.Understanding the dynamics of gas kick evolution and the associated pressure response characteristics is critical for effective well control.In...The gas kick represents a major risk in deepwater oil and gas exploration.Understanding the dynamics of gas kick evolution and the associated pressure response characteristics is critical for effective well control.In this paper,we introduce a transient wellbore multiphase flow model specifically developed to simulate gas kick in deepwater dual-gradient drilling,incorporating a downhole separator.The model accounts for the variable mass flow within the annulus and heat exchange between the annular fluid and the formation.Using this model,we analyzed the multiphase flow and thermodynamic behavior during the gas kick.Simulation results reveal a progressive increase in bottom-hole temperature,underscoring its potential as a key indicator for gas kick early detection.Additionally,variable gradient parameters affect not only the annular equivalent circulating density(ECD)profile but also the evolution of the gas kick.The inclusion of a downhole separator alters the annular ECD profile,creating a“broken line”shape,which enhances adaptability to the multi-pressure systems typically encountered in deepwater forma-tion.By adjusting factors such as hollow sphere concentration,separator position,and separation effi-ciency,the annular ECD profile can be effectively customized.This study provides important theoretical insights and practical applications for utilizing dual-gradient drilling technology to address challenges in deepwater formation drilling.展开更多
Lost circulation of drilling fluid is an international engineering problem during drilling.Aiming at the problems of the first-time lost circulation control success rate and poor adaptability of traditional lost circu...Lost circulation of drilling fluid is an international engineering problem during drilling.Aiming at the problems of the first-time lost circulation control success rate and poor adaptability of traditional lost circulation materials,a new self-healing lost circulation material based on dynamic disulfide bonds was prepared and named CKSH.In this paper,the particle size of self-healing lost circulation material was from 0.1 to 5 mm.The structure was analyzed by modern characterization means,and the drilling fluid compatibility,self-healing performance were evaluated.The self-healing and bridging-filling-sealing mechanism of CKSH were revealed.The results showed that the healing rate of CKSH could reach100%after 12 h over 70℃.It showed good compatibility with drilling fluid,with no effect on rheology or filtration loss.It could be stably suspended in drilling fluid,and the temperature resistance reached140℃.Healing by self-healing lost circulation materials of different particle size,the pressure bearing capacity of plugging zone were over 12 MPa for fracture opening of 1–5 mm.It could play a synergistic role with traditional lost circulation materials by chemical bonding,and the repeated loss caused by physical plugging was avoided.The research results of this paper can improve the bridging plugging bearing pressure strength and the first-time lost circulation control success rate,which is of great significance for improving drilling efficiency and reducing non-productive time.展开更多
Perovskite oxides(ABO_(3))are thought to be promising electrocatalysts for oxygen evolution reaction(OER),but their specific surface area(SSA)is too low(usually<10 m^(2) g^(−1)).Developing advanced ABO_(3) electroc...Perovskite oxides(ABO_(3))are thought to be promising electrocatalysts for oxygen evolution reaction(OER),but their specific surface area(SSA)is too low(usually<10 m^(2) g^(−1)).Developing advanced ABO_(3) electrocatalysts with high SSA and optimized structure is of great significance but remains a tremendous challenge.Herein,we propose a general strategy for fabrication of mesoporous perovskite oxide nanosheets(MPONs)with controllable atomic doping via self-sacrificial template-induced nanostructure modulation.A variety of MPONs including LaFeO_(3),A-site-doped LaFeO_(3)(A-LaFeO_(3),where A is Pr,Nd,Sm,Eu,or Gd)and B-site-doped LaFeO_(3)(B-LaFeO_(3),where B is Mn,Co,Ni,Cu,or Zn)have been achieved.Interestingly,it is discovered that the catalytic activities of A-LaFeO_(3) MPONs as OER catalysts are overall higher than those of B-LaFeO_(3) ones.Especially,the screened Eu-LaFeO_(3) MPONs only require a low overpotential of 267 mV at 10 mA cm^(−2),outperforming most reported perovskite oxides.The superior catalytic activity of Eu-LaFeO_(3) MPONs is attributed to their favorable porous structure,which increases the density of active sites,and enhanced lattice oxygen participation,which improves the intrinsic activity.This study provides guidance for the design and controlled synthesis of advanced rare-earth-doped MPONs with ultrahigh SSA for enhanced electrocatalysis.展开更多
To elucidate the fracturing mechanism of deep hard rock under complex disturbance environments,this study investigates the dynamic failure behavior of pre-damaged granite subjected to multi-source dynamic disturbances...To elucidate the fracturing mechanism of deep hard rock under complex disturbance environments,this study investigates the dynamic failure behavior of pre-damaged granite subjected to multi-source dynamic disturbances.Blasting vibration monitoring was conducted in a deep-buried drill-and-blast tunnel to characterize in-situ dynamic loading conditions.Subsequently,true triaxial compression tests incorporating multi-source disturbances were performed using a self-developed wide-low-frequency true triaxial system to simulate disturbance accumulation and damage evolution in granite.The results demonstrate that combined dynamic disturbances and unloading damage significantly accelerate strength degradation and trigger shear-slip failure along preferentially oriented blast-induced fractures,with strength reductions up to 16.7%.Layered failure was observed on the free surface of pre-damaged granite under biaxial loading,indicating a disturbance-induced fracture localization mechanism.Time-stress-fracture-energy coupling fields were constructed to reveal the spatiotemporal characteristics of fracture evolution.Critical precursor frequency bands(105-150,185-225,and 300-325 kHz)were identified,which serve as diagnostic signatures of impending failure.A dynamic instability mechanism driven by multi-source disturbance superposition and pre-damage evolution was established.Furthermore,a grouting-based wave-absorption control strategy was proposed to mitigate deep dynamic disasters by attenuating disturbance amplitude and reducing excitation frequency.展开更多
Intelligent fault diagnosis technology plays an indispensable role in ensuring the safety,stability,and efficiency of railway operations.However,existing studies have the following limitations.1)They are typical black-...Intelligent fault diagnosis technology plays an indispensable role in ensuring the safety,stability,and efficiency of railway operations.However,existing studies have the following limitations.1)They are typical black-box models that lacks interpretability as well as they fuse features by simply stacking them,overlooking the discrepancies in the importance of different features,which reduces the credibility and diagnosis accuracy of the models.2)They ignore the effects of potentially mistaken labels in the training datasets disrupting the ability of the models to learn the true data distribution,which degrades the generalization performance of intelligent diagnosis models,especially when the training samples are limited.To address the above items,an interpretable few-shot framework for fault diagnosis with noisy labels is proposed for train transmission systems.In the proposed framework,a feature extractor is constructed by stacked frequency band focus modules,which can capture signal features in different frequency bands and further adaptively concentrate on the features corresponding to the potential fault characteristic frequency.Then,according to prototypical network,a novel metric-based classifier is developed that is tolerant to mislabeled support samples in the case of limited samples.Besides,a new loss function is designed to decrease the impact of label mistakes in query datasets.Finally,fault simulation experiments of subway train transmission systems are designed and conducted,and the effectiveness as well as superiority of the proposed method are proved by ablation experiments and comparison with the existing methods.展开更多
This paper addresses the Multi-Vehicle Routing Problem with Time Windows and Simultaneous Pickup and Delivery(MVRPTWSPD),aiming to optimize logistics distribution routes and minimize total costs.A vehicle routing opti...This paper addresses the Multi-Vehicle Routing Problem with Time Windows and Simultaneous Pickup and Delivery(MVRPTWSPD),aiming to optimize logistics distribution routes and minimize total costs.A vehicle routing optimization model is developed based on the operational requirements of the KS Logistics Center,focusing on minimizing vehicle dispatch,loading and unloading,operating,and time window penalty costs.The model incorporates constraints such as vehicle capacity,time windows,and travel distance,and is solved using a genetic algorithm to ensure optimal route planning.Through MATLAB simulations,34 customer points are analyzed,demonstrating that the simultaneous pickup and delivery model reduces total costs by 30.13%,increases vehicle loading rates by 20.04%,and decreases travel distance compared to delivery-only or pickup-only models.The results demonstrate the significant advantages of the simultaneous pickup and delivery mode in reducing logistics costs and improving vehicle utilization,offering valuable insights for enhancing the operational efficiency of the KS Logistics Center.展开更多
Charge-neutral method(CNM)is extensively used in investigating the performance of catalysts and the mechanism of N_(2)electrochemical reduction(NRR).However,disparities remain between the predicted potentials required...Charge-neutral method(CNM)is extensively used in investigating the performance of catalysts and the mechanism of N_(2)electrochemical reduction(NRR).However,disparities remain between the predicted potentials required for NRR by the CNM methods and those observed experimentally,as the CNM method neglects the charge effect from the electrode potential.To address this issue,we employed the constant electrode potential(CEP)method to screen atomic transition metal-N-graphene(M_(1)/N-graphene)as NRR electrocatalysts and systematically investigated the underlying catalytic mechanism.Among eight types of M_(1)/N-graphene(M_(1)=Mo,W,Fe,Re,Ni,Co,V,Cr),W_(1)/N-graphene emerges as the most promising NRR electrocatalyst with a limiting potential as low as−0.13 V.Additionally,the W_(1)/N-graphene system consistently maintains a positive charge during the reaction due to its Fermi level being higher than that of the electrode.These results better match with the actual circumstances compared to those calculated by conventional CNM method.Thus,our work not only develops a promising electrocatalyst for NRR but also deepens the understanding of the intrinsic electrocatalytic mechanism.展开更多
Zwitterionic materials with covalently tethered cations and anions have great potential as electrolyte additives for aqueous Znion batteries(AZIBs)owing to their appealing intrinsic characteristics and merits.However,...Zwitterionic materials with covalently tethered cations and anions have great potential as electrolyte additives for aqueous Znion batteries(AZIBs)owing to their appealing intrinsic characteristics and merits.However,the impact of cationic and anionic moieties within zwitterions on enhancing the performance of AZIBs remains poorly understood.Herein,three zwitterions,namely carboxybetaine methacrylate(CBMA),sulfobetaine methacrylate(SBMA),and 2-methacryloyloxyethyl phosphorylcholine(MPC),were selected as additives to investigate their different action mechanisms in AZIBs.All three zwitterions have the same quaternary ammonium as the positively charged group,but having different negatively charged segments,i.e.,carboxylate,sulfonate,and phosphate for CBMA,SBMA,and MPC,respectively.By systematical electrochemical analysis,these zwitterions all contribute to enhanced cycling life of Zn anode,with MPC having the most pronounced effect,which can be attributed to the synergistic effect of positively quaternary ammonium group and unique negatively phosphate groups.As a result,the Zn//Zn cell with MPC as additive in ZnSO_(4)electrolyte exhibits an ultralong lifespan over 5000 h.This work proposes new insights to the future development of multifunctional zwitterionic additives for remarkably stable AZIBs.展开更多
High entropy materials(HEMs)are the promising electrocatalysts for anion exchange membrane electrolyser(AEMs)and proton exchange membrane fuel cells(PEMFCs)due to the intriguing cocktail effect,wide design space,tailo...High entropy materials(HEMs)are the promising electrocatalysts for anion exchange membrane electrolyser(AEMs)and proton exchange membrane fuel cells(PEMFCs)due to the intriguing cocktail effect,wide design space,tailorable electronic structure,and entropy stabilization effect.The precise fabrication of HEMs with functional nanostructures provides a crucial avenue to optimize the adsorption strength and catalytic activity for electrocatalysis.This review comprehensively summarizes the development of HEMs,focusing on the principles and strategies of structural design,and the catalytic mechanism towards hydrogen evolution reaction,oxygen evolution reaction and oxygen reduction reaction for the development of high-performance electrocatalysts.The complexity inherent in the interactions between different elements,the changes in the d-band center and the Gibbs free energies during the catalytic progress,as well as the coordination environment of the active sites associated with the unique crystal structure to improve the catalytic performance are discussed.We also provide a perspective on the challenges and future development direction of HEMs in electrocatalysis.This review will contribute to the design and development of HEMs-based catalysts for the next generation of electrochemical applications.展开更多
Recent interest in photocatalytic water splitting has intensified the demand in the development of photocatalysts capable of harnessing the full solar-spectrum.This study introduces a novel WO_(x)/ZnIn_(2)S_(4)Zscheme...Recent interest in photocatalytic water splitting has intensified the demand in the development of photocatalysts capable of harnessing the full solar-spectrum.This study introduces a novel WO_(x)/ZnIn_(2)S_(4)Zscheme heterojunction,prepared by depositing ZnIn_(2)S_(4)(ZIS)nanosheets onto WO_(x)nanorods,enabling efficient photothermal-coupled photocatalytic H_(2)evolution.The success relies on the engineered oxygen vacancies within WO_(x)nanorods,which not only confer excellent photothermal properties lowering the reaction barrier but also create defect levels in WO_(x)facilitating Z-scheme electron transfer from these levels to the valence band of ZIS.Consequently,the optimized WO_(x)/ZIS heterojunction exhibits a remarkable H_(2)evolution rate of 33.91 mmol h^(-1)g^(-1)with an apparent quantum efficiency of 23.6%at 400 nm.This study provides a new strategy for developing efficient Z-scheme heterojunctions with broadspectrum solar hydrogen production capabilities.展开更多
The trade-off between strength and ductility has long been a challenge for Mg alloy.To address this issue,bimodal-structured AZ80 Mg alloys with varying heterogeneity levels were fabricated via low-temperature extrusi...The trade-off between strength and ductility has long been a challenge for Mg alloy.To address this issue,bimodal-structured AZ80 Mg alloys with varying heterogeneity levels were fabricated via low-temperature extrusion in this work.The results reveal the microstructure comprising second-phase particle(SP_(p),β-Mg_(17)Al_(12)and Mg_(3) Mn_(2) Al_(18))-reinforced fine grains(FGs)FGs and SP_(p)-free coarse grains(CGs),with the heterogeneity level decreasing as extrusion temperature increases.As the heterogeneity level decreases,the synergistic deformation capacity initially improves,reaching a maximum at the moderate heterogeneity level of 0.31 GPa and 0.238,and then declines.This exceptional capacity is attributed to the hetero-deformation induced(HDI)stress,which effectively alleviates the strain gradients by activating〈c+a〉dislocations and non-basal〈a〉dislocations during deformation.An optimal combination of 287 MPa in yield strength,393 MPa in ultimate tensile strength,and 14.96%in elongation is achieved in the alloy with a moderate heterogeneity level.The excellent strength-ductility synergy originates from the enhanced capacity of dislocations accumulation driven by remarkable capacity of synergistic deformation and the synergistic strengthening mechanisms.This work provides a new insight into the design of bimodal structure to produce high-performance Mg alloys.展开更多
Re-entrant honeycombs are widely used in safeguard structures due to their geometric simplicity and excellent energy absorption capacities.However,traditional re-entrant honeycombs exhibit insufficient stiffness and s...Re-entrant honeycombs are widely used in safeguard structures due to their geometric simplicity and excellent energy absorption capacities.However,traditional re-entrant honeycombs exhibit insufficient stiffness and stability owing to the lack of internal support.This paper proposes a new hybrid honeycomb by integrating a chiral component inside the re-entrant honeycomb.Since Young's modulus is a key parameter to evaluate the energy absorption performance and stiffness,an analytical model is given to predict the effective Young's modulus of the proposed hybrid honeycomb.It is found that the optimal design scheme is to directly insert a circular ring inside the re-entrant honeycomb.The normalized specific energy absorption(SEA)of the hybrid honeycomb is 95%larger than that of the traditional re-entrant honeycomb.The normalized SEA first increases to a peak value and then decreases with the cell wall thickness.The optimal thickness of the cell wall for the maximum SEA is derived in terms of the geometric configuration of the unit cell.The normalized SEA first decreases to a valley value and then increases with the re-entrant angle.A longer horizontal cell wall results in a smaller normalized SEA.This paper provides a new design method for safeguard structures with high stiffness and energy absorption performance.展开更多
Missing data handling is vital for multi-sensor information fusion fault diagnosis of motors to prevent the accuracy decay or even model failure,and some promising results have been gained in several current studies.T...Missing data handling is vital for multi-sensor information fusion fault diagnosis of motors to prevent the accuracy decay or even model failure,and some promising results have been gained in several current studies.These studies,however,have the following limitations:1)effective supervision is neglected for missing data across different fault types and 2)imbalance in missing rates among fault types results in inadequate learning during model training.To overcome the above limitations,this paper proposes a dynamic relative advantagedriven multi-fault synergistic diagnosis method to accomplish accurate fault diagnosis of motors under imbalanced missing data rates.Firstly,a cross-fault-type generalized synergistic diagnostic strategy is established based on variational information bottleneck theory,which is able to ensure sufficient supervision in handling missing data.Then,a dynamic relative advantage assessment technique is designed to reduce diagnostic accuracy decay caused by imbalanced missing data rates.The proposed method is validated using multi-sensor data from motor fault simulation experiments,and experimental results demonstrate its effectiveness and superiority in improving diagnostic accuracy and generalization under imbalanced missing data rates.展开更多
Metals in advanced nuclear reactors,such as W,often experience microcracks.However,the synergistic effects of high temperature,stress,and specialized structures can improve the self-healing ability of these metals.Mic...Metals in advanced nuclear reactors,such as W,often experience microcracks.However,the synergistic effects of high temperature,stress,and specialized structures can improve the self-healing ability of these metals.Microcrack healing is closely related to crack surface conditions.The order and disorder degree of crack surface atoms may affect crack stability.In this study,first-principles calculations,ab initio molecular dynamics,and surface thermodynamic theory were used to investigate the stability of grain boundary(GB)cracks at 0,293,and 373 K.We compared the energy densities,crack attraction energies,and atomic diffusion behaviors of crack surfaces atΣ3 GBs with those atΣ5 GBs.Adsorption on the nanocrack surface determines the critical nanocrack width.It was found that AlΣ3(111)nanocracks heal at high temperatures,and this healing behavior is closely related to the crack surface energy.Meanwhile,the GB cracks of W heal in an orderly manner at 573 and 1203 K.BY contrast,the GB cracks of Ti remain unhealed.Finally,a high-temperature nanocrack expansion model was developed and used to predict crack behavior under applied stress at different temperatures.展开更多
In the field of nuclear radiation detection, sodium iodide (NaI(Tl)) and lanthanum bromide (LaBr<sub>3</sub>) are the primary scintillation crystals used for energy spectrum detectors. Furthermore, energy ...In the field of nuclear radiation detection, sodium iodide (NaI(Tl)) and lanthanum bromide (LaBr<sub>3</sub>) are the primary scintillation crystals used for energy spectrum detectors. Furthermore, energy spectrum detectors based on gadolinium gallium aluminum garnet (Ce:GAGG) scintillation crystals are minor. In this work, a 1-inch Ce:GAGG and Silicon Photomultipliers (SiPMs) are employed to construct a detector, and the coupled medium was silicone oil. An optimal SiPMs quantity scheme for the energy resolution was determined by varying the number of SiPMs coupled to Ce:GAGG and studying the effect of the different number of SiPMs on the energy resolution of the detector. Energy-resolution contrast experiments between Ce:GAGG and NaI(Tl) were performed using this scheme. The experimental results demonstrate that increasing the number of SiPMs enhances the energy resolution of the detector significantly. Notably, the energy resolution of the Ce:GAGG detector is comparable to that of the NaI(Tl) detector. Additionally, both detectors exhibit an energy linearity exceeding 99.9%. .展开更多
Objective:To investigate the effect of ischemic precondition to protect ischemia-reperfusion injury and reduce IL-6 expression in the rats liver transplantation.Methods:The rat portal vein infusion of autologous liver...Objective:To investigate the effect of ischemic precondition to protect ischemia-reperfusion injury and reduce IL-6 expression in the rats liver transplantation.Methods:The rat portal vein infusion of autologous liver transplantation model were used.The rats were divided into ischemic preconditioning rats liver transplantation group(A group),the rats liver transplantation group(B group) and the normal rat control group(C group).Then we analyzed the changes of liver function,liver microstructure and the expression of IL-6,SOD and MDA within 48 h.Results: The pathology of liver in group A showed lobular architecture essentially normal,the liver cells was slightly swell and no significant changes in postoperative 12 h.In transmission electron microscope(46 000X).the mitochondria of liver cells in group A i】ecame swelling,elliptical can cristae partially broken.But there still has a small amount of arrangement.While that in group, the mitochondria were swollen,became round,serious visible crest reduce or ruptured.The result of over function test showed that the serum ALT and AST levels in group A and B were both higher than that in group C at each time period,but the serum ALT and AST levels in group A were lower than that in group B.The expression changes of IL-6 in group B were higher than that in group A and R(P【0.05).The expression of MDA in group A is more obvious than that in group B(P【0.05).Conclusions:Ischemic precondition could alleviate part of ischemia-reperfusion injury in the rat liver transplantation,and also could reduce IL-6 expression to protect the liver cells against liver damage and inflammatory cytokine production.展开更多
文摘The Editor-in-Chief has retracted this article.Following this publication,concerns were raised regarding the similarity of images presented in this article with previously published articles[1,2].The authors were unable to provide a satisfactory explanation and raw data for the concerns upon request.
基金supported by the Postdoctoral Fellow-ship Program of CPSF(Grant No.GZC20233105)the Science Foundation of China University of Petroleum,Beijing(Grant No.2462024XKBH006)+2 种基金the China Postdoctoral Science Foundation(Grant No.2024M753615)the Major Scientific Research Instrument Development Program of National Natural Science Foundation of China(Grant No.52227804)the Youth Science Foundation Program of National Natural Science Foundation of China(Grant No.52404012).
文摘The gas kick represents a major risk in deepwater oil and gas exploration.Understanding the dynamics of gas kick evolution and the associated pressure response characteristics is critical for effective well control.In this paper,we introduce a transient wellbore multiphase flow model specifically developed to simulate gas kick in deepwater dual-gradient drilling,incorporating a downhole separator.The model accounts for the variable mass flow within the annulus and heat exchange between the annular fluid and the formation.Using this model,we analyzed the multiphase flow and thermodynamic behavior during the gas kick.Simulation results reveal a progressive increase in bottom-hole temperature,underscoring its potential as a key indicator for gas kick early detection.Additionally,variable gradient parameters affect not only the annular equivalent circulating density(ECD)profile but also the evolution of the gas kick.The inclusion of a downhole separator alters the annular ECD profile,creating a“broken line”shape,which enhances adaptability to the multi-pressure systems typically encountered in deepwater forma-tion.By adjusting factors such as hollow sphere concentration,separator position,and separation effi-ciency,the annular ECD profile can be effectively customized.This study provides important theoretical insights and practical applications for utilizing dual-gradient drilling technology to address challenges in deepwater formation drilling.
基金supported by National Natural Science Foundation of China(52304006,52274032,and 51774062)the General Project of the Chongqing Natural Science Foundation(CSTB2022NSCQ-MSX1554 and CSTB2022NSCQ-MSX0349)Shaanxi Province Key Laboratory of Environmental Pollution Control and Reservoir Protection Technology of Oilfields and Engineering Research Center of Oil and Gas Field Chemistry,Universities of Shaanxi Province(XSYU-CCCE-2402).
文摘Lost circulation of drilling fluid is an international engineering problem during drilling.Aiming at the problems of the first-time lost circulation control success rate and poor adaptability of traditional lost circulation materials,a new self-healing lost circulation material based on dynamic disulfide bonds was prepared and named CKSH.In this paper,the particle size of self-healing lost circulation material was from 0.1 to 5 mm.The structure was analyzed by modern characterization means,and the drilling fluid compatibility,self-healing performance were evaluated.The self-healing and bridging-filling-sealing mechanism of CKSH were revealed.The results showed that the healing rate of CKSH could reach100%after 12 h over 70℃.It showed good compatibility with drilling fluid,with no effect on rheology or filtration loss.It could be stably suspended in drilling fluid,and the temperature resistance reached140℃.Healing by self-healing lost circulation materials of different particle size,the pressure bearing capacity of plugging zone were over 12 MPa for fracture opening of 1–5 mm.It could play a synergistic role with traditional lost circulation materials by chemical bonding,and the repeated loss caused by physical plugging was avoided.The research results of this paper can improve the bridging plugging bearing pressure strength and the first-time lost circulation control success rate,which is of great significance for improving drilling efficiency and reducing non-productive time.
基金financially supported by the National Key Research and Development Program(Nos.2022YFB2502104 and 2022YFA1602700)the Key Research and Development Program of Jiangsu Provincial Department of Science and Technology of China(No.BE2022332)+4 种基金the Jiangsu Carbon Peak Carbon Neutralization Science and Technology Innovation Special Fund(No.BE2022605)the National Natural Science Foundation of China(Nos.22109073,22379071)the DECRA program of Australian Research Council(No.DE230100357)the JSPS KAKENHI(No.JP23K13703)the Center for Computational Materials Science,Institute for Materials Research,Tohoku University for the use of MASAMUNE-IMR(202312-SCKXX-0203)。
文摘Perovskite oxides(ABO_(3))are thought to be promising electrocatalysts for oxygen evolution reaction(OER),but their specific surface area(SSA)is too low(usually<10 m^(2) g^(−1)).Developing advanced ABO_(3) electrocatalysts with high SSA and optimized structure is of great significance but remains a tremendous challenge.Herein,we propose a general strategy for fabrication of mesoporous perovskite oxide nanosheets(MPONs)with controllable atomic doping via self-sacrificial template-induced nanostructure modulation.A variety of MPONs including LaFeO_(3),A-site-doped LaFeO_(3)(A-LaFeO_(3),where A is Pr,Nd,Sm,Eu,or Gd)and B-site-doped LaFeO_(3)(B-LaFeO_(3),where B is Mn,Co,Ni,Cu,or Zn)have been achieved.Interestingly,it is discovered that the catalytic activities of A-LaFeO_(3) MPONs as OER catalysts are overall higher than those of B-LaFeO_(3) ones.Especially,the screened Eu-LaFeO_(3) MPONs only require a low overpotential of 267 mV at 10 mA cm^(−2),outperforming most reported perovskite oxides.The superior catalytic activity of Eu-LaFeO_(3) MPONs is attributed to their favorable porous structure,which increases the density of active sites,and enhanced lattice oxygen participation,which improves the intrinsic activity.This study provides guidance for the design and controlled synthesis of advanced rare-earth-doped MPONs with ultrahigh SSA for enhanced electrocatalysis.
基金supported by the National Key R&D Program of China(No.2023YFB2603602)the National Natural Science Foundation of China(Nos.52222810 and 52178383).
文摘To elucidate the fracturing mechanism of deep hard rock under complex disturbance environments,this study investigates the dynamic failure behavior of pre-damaged granite subjected to multi-source dynamic disturbances.Blasting vibration monitoring was conducted in a deep-buried drill-and-blast tunnel to characterize in-situ dynamic loading conditions.Subsequently,true triaxial compression tests incorporating multi-source disturbances were performed using a self-developed wide-low-frequency true triaxial system to simulate disturbance accumulation and damage evolution in granite.The results demonstrate that combined dynamic disturbances and unloading damage significantly accelerate strength degradation and trigger shear-slip failure along preferentially oriented blast-induced fractures,with strength reductions up to 16.7%.Layered failure was observed on the free surface of pre-damaged granite under biaxial loading,indicating a disturbance-induced fracture localization mechanism.Time-stress-fracture-energy coupling fields were constructed to reveal the spatiotemporal characteristics of fracture evolution.Critical precursor frequency bands(105-150,185-225,and 300-325 kHz)were identified,which serve as diagnostic signatures of impending failure.A dynamic instability mechanism driven by multi-source disturbance superposition and pre-damage evolution was established.Furthermore,a grouting-based wave-absorption control strategy was proposed to mitigate deep dynamic disasters by attenuating disturbance amplitude and reducing excitation frequency.
基金supported in part by the National Key R&D Program of China under Grant 2022YFB4300601in part by the State Key Laboratory of Advanced Rail Autonomous Operation under Grant RAO2023ZZ003.
文摘Intelligent fault diagnosis technology plays an indispensable role in ensuring the safety,stability,and efficiency of railway operations.However,existing studies have the following limitations.1)They are typical black-box models that lacks interpretability as well as they fuse features by simply stacking them,overlooking the discrepancies in the importance of different features,which reduces the credibility and diagnosis accuracy of the models.2)They ignore the effects of potentially mistaken labels in the training datasets disrupting the ability of the models to learn the true data distribution,which degrades the generalization performance of intelligent diagnosis models,especially when the training samples are limited.To address the above items,an interpretable few-shot framework for fault diagnosis with noisy labels is proposed for train transmission systems.In the proposed framework,a feature extractor is constructed by stacked frequency band focus modules,which can capture signal features in different frequency bands and further adaptively concentrate on the features corresponding to the potential fault characteristic frequency.Then,according to prototypical network,a novel metric-based classifier is developed that is tolerant to mislabeled support samples in the case of limited samples.Besides,a new loss function is designed to decrease the impact of label mistakes in query datasets.Finally,fault simulation experiments of subway train transmission systems are designed and conducted,and the effectiveness as well as superiority of the proposed method are proved by ablation experiments and comparison with the existing methods.
文摘This paper addresses the Multi-Vehicle Routing Problem with Time Windows and Simultaneous Pickup and Delivery(MVRPTWSPD),aiming to optimize logistics distribution routes and minimize total costs.A vehicle routing optimization model is developed based on the operational requirements of the KS Logistics Center,focusing on minimizing vehicle dispatch,loading and unloading,operating,and time window penalty costs.The model incorporates constraints such as vehicle capacity,time windows,and travel distance,and is solved using a genetic algorithm to ensure optimal route planning.Through MATLAB simulations,34 customer points are analyzed,demonstrating that the simultaneous pickup and delivery model reduces total costs by 30.13%,increases vehicle loading rates by 20.04%,and decreases travel distance compared to delivery-only or pickup-only models.The results demonstrate the significant advantages of the simultaneous pickup and delivery mode in reducing logistics costs and improving vehicle utilization,offering valuable insights for enhancing the operational efficiency of the KS Logistics Center.
基金Natural Science Foundation of Guangdong Province(No.2024A1515011094(C.Q Sun))National Natural Science Foundation of China(Nos.12304243(H.X.Fang),12150100(B.Wang))is gratefully acknowledged。
文摘Charge-neutral method(CNM)is extensively used in investigating the performance of catalysts and the mechanism of N_(2)electrochemical reduction(NRR).However,disparities remain between the predicted potentials required for NRR by the CNM methods and those observed experimentally,as the CNM method neglects the charge effect from the electrode potential.To address this issue,we employed the constant electrode potential(CEP)method to screen atomic transition metal-N-graphene(M_(1)/N-graphene)as NRR electrocatalysts and systematically investigated the underlying catalytic mechanism.Among eight types of M_(1)/N-graphene(M_(1)=Mo,W,Fe,Re,Ni,Co,V,Cr),W_(1)/N-graphene emerges as the most promising NRR electrocatalyst with a limiting potential as low as−0.13 V.Additionally,the W_(1)/N-graphene system consistently maintains a positive charge during the reaction due to its Fermi level being higher than that of the electrode.These results better match with the actual circumstances compared to those calculated by conventional CNM method.Thus,our work not only develops a promising electrocatalyst for NRR but also deepens the understanding of the intrinsic electrocatalytic mechanism.
基金supported by the Australian Research Council(LP220100036)the National Key Research and Development Program(2022YFB2502104 and 2022YFA1602700)+3 种基金the Key Research and Development Program of Jiangsu Provincial Department of Science and Technology of China(BE2022332)the Jiangsu Carbon Peak Carbon Neutralization Science and Technology Innovation Special Fund(BE2022605)the Australian Research Council for his Discovery Early Career Researcher Award fellowship(DE230101105)the China Scholarship Council(CSC,grant no.202306190185)for funding a scholarship。
文摘Zwitterionic materials with covalently tethered cations and anions have great potential as electrolyte additives for aqueous Znion batteries(AZIBs)owing to their appealing intrinsic characteristics and merits.However,the impact of cationic and anionic moieties within zwitterions on enhancing the performance of AZIBs remains poorly understood.Herein,three zwitterions,namely carboxybetaine methacrylate(CBMA),sulfobetaine methacrylate(SBMA),and 2-methacryloyloxyethyl phosphorylcholine(MPC),were selected as additives to investigate their different action mechanisms in AZIBs.All three zwitterions have the same quaternary ammonium as the positively charged group,but having different negatively charged segments,i.e.,carboxylate,sulfonate,and phosphate for CBMA,SBMA,and MPC,respectively.By systematical electrochemical analysis,these zwitterions all contribute to enhanced cycling life of Zn anode,with MPC having the most pronounced effect,which can be attributed to the synergistic effect of positively quaternary ammonium group and unique negatively phosphate groups.As a result,the Zn//Zn cell with MPC as additive in ZnSO_(4)electrolyte exhibits an ultralong lifespan over 5000 h.This work proposes new insights to the future development of multifunctional zwitterionic additives for remarkably stable AZIBs.
基金supported by the Guangdong Basic and Applied Basic Research Fund Project(2022A1515140061,No.11000-2344014)Startup Foundation for Postdoctor by Dongguan University of Technology(No.11000-221110149)the High-level Talents Program(contract number 2023JC10L014)of the Department of Science and Technology of Guangdong Province。
文摘High entropy materials(HEMs)are the promising electrocatalysts for anion exchange membrane electrolyser(AEMs)and proton exchange membrane fuel cells(PEMFCs)due to the intriguing cocktail effect,wide design space,tailorable electronic structure,and entropy stabilization effect.The precise fabrication of HEMs with functional nanostructures provides a crucial avenue to optimize the adsorption strength and catalytic activity for electrocatalysis.This review comprehensively summarizes the development of HEMs,focusing on the principles and strategies of structural design,and the catalytic mechanism towards hydrogen evolution reaction,oxygen evolution reaction and oxygen reduction reaction for the development of high-performance electrocatalysts.The complexity inherent in the interactions between different elements,the changes in the d-band center and the Gibbs free energies during the catalytic progress,as well as the coordination environment of the active sites associated with the unique crystal structure to improve the catalytic performance are discussed.We also provide a perspective on the challenges and future development direction of HEMs in electrocatalysis.This review will contribute to the design and development of HEMs-based catalysts for the next generation of electrochemical applications.
基金supported by the National Key Research and Development Program of China(2022YFB3803600)the National Natural Science Foundation of China(52276212)+4 种基金the Natural Science Foundation of Jiangsu Province(BK20231211)the Suzhou Science and Technology Program(SYG202101)the Key Research and Development Program in Shaanxi Province of China(2023-YBGY-300)the Zhuhai Innovation and Entrepreneurship Team Project(2120004000225)the China Fundamental Research Funds for the Central Universities。
文摘Recent interest in photocatalytic water splitting has intensified the demand in the development of photocatalysts capable of harnessing the full solar-spectrum.This study introduces a novel WO_(x)/ZnIn_(2)S_(4)Zscheme heterojunction,prepared by depositing ZnIn_(2)S_(4)(ZIS)nanosheets onto WO_(x)nanorods,enabling efficient photothermal-coupled photocatalytic H_(2)evolution.The success relies on the engineered oxygen vacancies within WO_(x)nanorods,which not only confer excellent photothermal properties lowering the reaction barrier but also create defect levels in WO_(x)facilitating Z-scheme electron transfer from these levels to the valence band of ZIS.Consequently,the optimized WO_(x)/ZIS heterojunction exhibits a remarkable H_(2)evolution rate of 33.91 mmol h^(-1)g^(-1)with an apparent quantum efficiency of 23.6%at 400 nm.This study provides a new strategy for developing efficient Z-scheme heterojunctions with broadspectrum solar hydrogen production capabilities.
基金funded by the Guangdong Province general university Young Innovative Talents Program Project(2024KQNCX153)Postdoctoral Research Start-up Funds of Dongguan University of Technology。
文摘The trade-off between strength and ductility has long been a challenge for Mg alloy.To address this issue,bimodal-structured AZ80 Mg alloys with varying heterogeneity levels were fabricated via low-temperature extrusion in this work.The results reveal the microstructure comprising second-phase particle(SP_(p),β-Mg_(17)Al_(12)and Mg_(3) Mn_(2) Al_(18))-reinforced fine grains(FGs)FGs and SP_(p)-free coarse grains(CGs),with the heterogeneity level decreasing as extrusion temperature increases.As the heterogeneity level decreases,the synergistic deformation capacity initially improves,reaching a maximum at the moderate heterogeneity level of 0.31 GPa and 0.238,and then declines.This exceptional capacity is attributed to the hetero-deformation induced(HDI)stress,which effectively alleviates the strain gradients by activating〈c+a〉dislocations and non-basal〈a〉dislocations during deformation.An optimal combination of 287 MPa in yield strength,393 MPa in ultimate tensile strength,and 14.96%in elongation is achieved in the alloy with a moderate heterogeneity level.The excellent strength-ductility synergy originates from the enhanced capacity of dislocations accumulation driven by remarkable capacity of synergistic deformation and the synergistic strengthening mechanisms.This work provides a new insight into the design of bimodal structure to produce high-performance Mg alloys.
基金Project supported by Guangdong Basic and Applied Basic Research Foundation(Nos.2022A1515240072,2023A1515240053,2022B1515020099,and 2023A1515012641)Shenzhen Science and Technology Program(No.JCYJ20220818102409020)the National Natural Science Foundation of China(Nos.12102104 and 12002180)。
文摘Re-entrant honeycombs are widely used in safeguard structures due to their geometric simplicity and excellent energy absorption capacities.However,traditional re-entrant honeycombs exhibit insufficient stiffness and stability owing to the lack of internal support.This paper proposes a new hybrid honeycomb by integrating a chiral component inside the re-entrant honeycomb.Since Young's modulus is a key parameter to evaluate the energy absorption performance and stiffness,an analytical model is given to predict the effective Young's modulus of the proposed hybrid honeycomb.It is found that the optimal design scheme is to directly insert a circular ring inside the re-entrant honeycomb.The normalized specific energy absorption(SEA)of the hybrid honeycomb is 95%larger than that of the traditional re-entrant honeycomb.The normalized SEA first increases to a peak value and then decreases with the cell wall thickness.The optimal thickness of the cell wall for the maximum SEA is derived in terms of the geometric configuration of the unit cell.The normalized SEA first decreases to a valley value and then increases with the re-entrant angle.A longer horizontal cell wall results in a smaller normalized SEA.This paper provides a new design method for safeguard structures with high stiffness and energy absorption performance.
文摘Missing data handling is vital for multi-sensor information fusion fault diagnosis of motors to prevent the accuracy decay or even model failure,and some promising results have been gained in several current studies.These studies,however,have the following limitations:1)effective supervision is neglected for missing data across different fault types and 2)imbalance in missing rates among fault types results in inadequate learning during model training.To overcome the above limitations,this paper proposes a dynamic relative advantagedriven multi-fault synergistic diagnosis method to accomplish accurate fault diagnosis of motors under imbalanced missing data rates.Firstly,a cross-fault-type generalized synergistic diagnostic strategy is established based on variational information bottleneck theory,which is able to ensure sufficient supervision in handling missing data.Then,a dynamic relative advantage assessment technique is designed to reduce diagnostic accuracy decay caused by imbalanced missing data rates.The proposed method is validated using multi-sensor data from motor fault simulation experiments,and experimental results demonstrate its effectiveness and superiority in improving diagnostic accuracy and generalization under imbalanced missing data rates.
基金supported by the National Natural Science Foundation of China(Nos.12175323,11832019,and 11705264)project supported by the State Key Laboratory of Powder Metallurgy,Central South University,Guangdong Basic and Applied Basic Research Foundation(2023A1515012692)the National Natural Science Foundation of China Original Exploration Project(12150001).
文摘Metals in advanced nuclear reactors,such as W,often experience microcracks.However,the synergistic effects of high temperature,stress,and specialized structures can improve the self-healing ability of these metals.Microcrack healing is closely related to crack surface conditions.The order and disorder degree of crack surface atoms may affect crack stability.In this study,first-principles calculations,ab initio molecular dynamics,and surface thermodynamic theory were used to investigate the stability of grain boundary(GB)cracks at 0,293,and 373 K.We compared the energy densities,crack attraction energies,and atomic diffusion behaviors of crack surfaces atΣ3 GBs with those atΣ5 GBs.Adsorption on the nanocrack surface determines the critical nanocrack width.It was found that AlΣ3(111)nanocracks heal at high temperatures,and this healing behavior is closely related to the crack surface energy.Meanwhile,the GB cracks of W heal in an orderly manner at 573 and 1203 K.BY contrast,the GB cracks of Ti remain unhealed.Finally,a high-temperature nanocrack expansion model was developed and used to predict crack behavior under applied stress at different temperatures.
文摘In the field of nuclear radiation detection, sodium iodide (NaI(Tl)) and lanthanum bromide (LaBr<sub>3</sub>) are the primary scintillation crystals used for energy spectrum detectors. Furthermore, energy spectrum detectors based on gadolinium gallium aluminum garnet (Ce:GAGG) scintillation crystals are minor. In this work, a 1-inch Ce:GAGG and Silicon Photomultipliers (SiPMs) are employed to construct a detector, and the coupled medium was silicone oil. An optimal SiPMs quantity scheme for the energy resolution was determined by varying the number of SiPMs coupled to Ce:GAGG and studying the effect of the different number of SiPMs on the energy resolution of the detector. Energy-resolution contrast experiments between Ce:GAGG and NaI(Tl) were performed using this scheme. The experimental results demonstrate that increasing the number of SiPMs enhances the energy resolution of the detector significantly. Notably, the energy resolution of the Ce:GAGG detector is comparable to that of the NaI(Tl) detector. Additionally, both detectors exhibit an energy linearity exceeding 99.9%. .
文摘Objective:To investigate the effect of ischemic precondition to protect ischemia-reperfusion injury and reduce IL-6 expression in the rats liver transplantation.Methods:The rat portal vein infusion of autologous liver transplantation model were used.The rats were divided into ischemic preconditioning rats liver transplantation group(A group),the rats liver transplantation group(B group) and the normal rat control group(C group).Then we analyzed the changes of liver function,liver microstructure and the expression of IL-6,SOD and MDA within 48 h.Results: The pathology of liver in group A showed lobular architecture essentially normal,the liver cells was slightly swell and no significant changes in postoperative 12 h.In transmission electron microscope(46 000X).the mitochondria of liver cells in group A i】ecame swelling,elliptical can cristae partially broken.But there still has a small amount of arrangement.While that in group, the mitochondria were swollen,became round,serious visible crest reduce or ruptured.The result of over function test showed that the serum ALT and AST levels in group A and B were both higher than that in group C at each time period,but the serum ALT and AST levels in group A were lower than that in group B.The expression changes of IL-6 in group B were higher than that in group A and R(P【0.05).The expression of MDA in group A is more obvious than that in group B(P【0.05).Conclusions:Ischemic precondition could alleviate part of ischemia-reperfusion injury in the rat liver transplantation,and also could reduce IL-6 expression to protect the liver cells against liver damage and inflammatory cytokine production.
