The pursuit of Ag-based alloys with both high strength and toughness has posed a longstanding chal-lenge.In this study,we investigated the cluster strengthening and grain refinement toughening mecha-nisms in fully oxi...The pursuit of Ag-based alloys with both high strength and toughness has posed a longstanding chal-lenge.In this study,we investigated the cluster strengthening and grain refinement toughening mecha-nisms in fully oxidized AgMgNi alloys,which were internally oxidized at 800℃ for 8 h under an oxy-gen atmosphere.We found that Mg-O clusters contributed to the hardening(138 HV)and strengthening(376.9 MPa)of the AgMg alloy through solid solution strengthening effects,albeit at the expense of duc-tility.To address this limitation,we introduced Ni nanoparticles into the AgMg alloy,resulting in signifi-cant grain refinement within its microstructure.Specifically,the grain size decreased from 67.2μm in the oxidized AgMg alloy to below 6.0μm in the oxidized AgMgNi alloy containing 0.3 wt%Ni.Consequently,the toughness increased significantly,rising from toughness value of 2177.9 MJ m^(-3) in the oxidized AgMg alloy to 6186.1 MJ m^(-3) in the oxidized AgMgNi alloy,representing a remarkable 2.8-fold enhancement.Furthermore,the internally oxidized AgMgNi alloy attained a strength of up to 387.6 MPa,comparable to that of the internally oxidized AgMg alloy,thereby demonstrating the successful realization of concurrent strengthening and toughening.These results collectively offer a novel approach for the design of high-performance alloys through the synergistic combination of cluster strengthening and grain refinement toughening.展开更多
The accuracy and reliability of non-destructive testing(NDT)approaches in detecting interior corrosion problems are critical,yet research in this field is limited.This work describes a novel way to monitor the structu...The accuracy and reliability of non-destructive testing(NDT)approaches in detecting interior corrosion problems are critical,yet research in this field is limited.This work describes a novel way to monitor the structural integrity of steel gas pipelines that uses advanced numerical modeling techniques to anticipate fracture development and corrosion effects.The objective is to increase pipeline dependability and safety through more precise,real-time health evaluations.Compared to previous approaches,our solution provides higher accuracy in fault detection and quantification,making it ideal for pipeline integritymonitoring in real-world applications.To solve this issue,statistical analysis was conducted on the size and directional distribution features of about 380,000 sets of internal corrosion faults,as well as simulations of erosion and wear patterns on bent pipes.Using real defectmorphologies,we developed a modeling framework for typical interior corrosion flaws.We evaluated and validated the applicability and effectiveness of in-service inspection processes,as well as conducted on-site comparison tests.The results show that(1)the length and width of corrosion defects follow a log-normal distribution,the clock orientation follows a normal distribution,and the peak depth follows a Freundlich EX function distribution pattern;(2)pipeline corrosion defect data can be classified into three classes using the K-means clustering algorithm,allowing rapid and convenient acquisition of typical size and orientation characteristics of internal corrosion defects;(3)the applicability range and boundary conditions of various NDT techniques were verified,establishing comprehensive selection principles for internal corrosion defect detection technology;(4)on-site inspection results showed a 31%The simulation and validation platform for typical interior corrosion issues greatly enhances the accuracy and reliability of detection data.展开更多
Horizontal wells play a crucial role in enhancing shale gas reservoir production.This study employs transient multiphase simulation to investigate the impact of well trajectory on production optimization throughout a ...Horizontal wells play a crucial role in enhancing shale gas reservoir production.This study employs transient multiphase simulation to investigate the impact of well trajectory on production optimization throughout a well’s life cycle.The research uses OLGATM as a simulator to examine six well trajectories:toe-up,toe-down,smooth horizontal,undulated toe-up,undulated toe-down,and undulated horizontal.Initial findings indicate comparable production rates across different trajectories during the early production phase,with toe-up wells showing slightly better performances due to minimal slugging.However,as the reservoir pressure decreases,the well trajectory significantly influences production.Horizontal wells achieve the highest accumulated gas production rates due to minimal liquid holdup and back pressure.Toe-up wells experience early liquid accumulation and severe slugging,leading to increased back pressure and smaller production.The study highlights the positive effects of lateral undulations on toe-up and toe-down wells in terms of liquid unloading,however some emphasis is also put on their adverse influence on horizontal wells.展开更多
Nitrate-to-ammonia conversion presents an effective method to remediate nitrate pollution while transforming waste into a valuable product and has recently garnered significant attention.Beyond the extensively studied...Nitrate-to-ammonia conversion presents an effective method to remediate nitrate pollution while transforming waste into a valuable product and has recently garnered significant attention.Beyond the extensively studied Cu-based catalysts,Co has also garnered significant attention.Identifying the real active sites and elucidating the mechanisms are urgently needed for its development in nitrate reduction.Co_(3)O_(4),particularly its Co^(3+)sites,is an established active phase for nitrate reduction and has been extensively studied.However,unlike the deliberate construction of the Co_(3)O_(4)phase or introducing doping to expose more Co^(3+)in the previous studies,it was found in this work that the active species above could be generated in Ni-Co double hydroxides in the context of nitrate reduction.The in situ generated Co_(3)O_(4),especially the spontaneously more exposed octahedrally coordinated Co^(3+),can significantly facilitate the crucial adsorption of Nand thus the following reaction.Furthermore,incorporated Ni sites accelerate nitrate reduction kinetics by promoting hydrogenation,facilitated by their H^(*)-generating capability.This enhanced catalytic activity yields a superior NH_(3)production rate of 7.05 mmol h^(-1)cm^(-2).Besides,a new and more efficient approach for nitrate remediation that focuses on the nitrate sources was proposed and verified through experimentation.展开更多
Nanolaminates are composed of nanoscale-thick alternating layers of different materials and their properties are dependent on the individual layers,the layer thickness and the interfaces between the layers.Nanolaminat...Nanolaminates are composed of nanoscale-thick alternating layers of different materials and their properties are dependent on the individual layers,the layer thickness and the interfaces between the layers.Nanolaminates composed of cubic crystal structured metals are usually ductile compared to nanolaminates containing hexagonal crystal structured metals.Mechanical properties such as strength and hardness of nanolaminates increase with a decrease in individual layer thickness down to a few nanometers and they become independent when the thickness of individual layers is less than a couple of nanometers.This review provides a detailed analysis of the effects of individual layer thickness and the interface structures on the strength and the strengthening mecha nisms of nanolaminates,their ductility and fracture behavior in terms of structural variations including grain morphologies,nanotwins,amorphous phases and crystal structures of the layers.The principles for designing nanolaminates with exceptionally high mechanical and physical properties and their fabrication are also highlighted.Some contradictory issues such as strengthening mechanisms,elastic modulus dependency on individual layer thickness and the effect of a thin amorphous layer on the strength are discussed.This review also provides future research directions in designing the high-strength nanolaminates that will facilitate practical engineering applications through analyzing up-to-date research efforts.展开更多
Based on the nondestructive test data of operating railway tunnels in China, this paper summarizes the basic characteristics of the complex contact behavior between the rock mass and lining structure. The contact mode...Based on the nondestructive test data of operating railway tunnels in China, this paper summarizes the basic characteristics of the complex contact behavior between the rock mass and lining structure. The contact modes are classified into dense contact, local non-contact, and loose contact. Subsequently, the corresponding mechanical model for each contact mode is developed according to its mechanical characteristics using the complex variable method. In the proposed mechanical model, a special algorithm is introduced to detect whether the local non-contact zone is re-contacted. Besides, a novel conformal mapping method is also proposed to accurately calculate the mechanical response of the concrete lining. Finally, the accuracy of the proposed method is verified by comparing it with the finite element method(FEM). Several parameter investigations are conducted to analyze the effects of different contact modes on the rock-lining interaction. The results show that:(i) the height of the local noncontact area does not have a significant effect on the contact stress distribution if no re-contact occurs;(ii) backfill grouting can reduce the local stress concentration caused by poor contact modes;and(iii) reducing the friction coefficient of the interface can lead to a more uniform distribution of internal forces in the concrete lining.展开更多
Bimetallic transition metal phosphides(TMPs)as potential candidates for superior electrochemical performance are still facing great challenges in the controllable preparation of two-dimensional(2 D)structures with hig...Bimetallic transition metal phosphides(TMPs)as potential candidates for superior electrochemical performance are still facing great challenges in the controllable preparation of two-dimensional(2 D)structures with high aspect ratio.Herein,a novel structure of quasi-monolayered NiCo-bimetal-phosphide(NiCoP)has been designed and successfully synthesized by the newly developed process combined with ultrasonic-cavitation and phase-transition.This is the first time to break through the controllable preparation of 2 D bimetal-phosphides with a thickness of 0.98 nm in sub-nanoscale.Based on the advantages of 2 D quasi-monolayer structure with dense crystalline-amorphous interface and the reconfigured electronic structure between Ni^(δ+)/Co^(δ+)and P^(δ-),the optimized Ni_(5%)CoP exhibits an outstanding bifunctional performance for electrocatalyzing both hydrogen evolution reaction and oxygen evolution reaction in an alkaline medium.Ni_(5%)CoP presents lower overpotentials and voltage of 84 mV&259 mV and1.48 V at the current density of 10 mA cm^(-2)for HER&DER and overall water splitting,respectively,which are superior to most other reported 2 D bimetal-phosphides.This work provides a new strategy to optimize the performance of electrolytic water for bimetal-phosphates and it may be of significant value in extending the design of other ultrathin 2 D structured catalysts.展开更多
The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum c...The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum catalysts(Pt/C/PTFE) with high efficiency as reported previously for LPCE were prepared and comprehensive performance evaluation method is applied to evaluate the separation behaviors of LPCE systematically. Experimental results indicate that the optimum reaction temperature of 60–80℃ and the molar feed ratio G/L of 1.5–2.5 would lead to higher separation efficiencies. As to the packing method, a random packing mode with a packing ratio of hydrophobic catalysts 0.25 is recommended. In addition, thermodynamic analysis corresponds well with experimental results under lower temperature and G/L, while the suppression of kinetic factors should not be neglected when T > 80℃ and G/L > 1.5.展开更多
In-situ fluid phase behavior is important in determining hydrocarbon contents and the multiphase flow through shale reservoirs.The gas-to-oil ratio(GOR) has been recognized as a critical indicator of fluid types.Howev...In-situ fluid phase behavior is important in determining hydrocarbon contents and the multiphase flow through shale reservoirs.The gas-to-oil ratio(GOR) has been recognized as a critical indicator of fluid types.However,little is known about the impact of fluid phase variation across the thermal maturity on shale oil/gas production(e.g.,estimated ultimate recovery,EUR).According to the specific gravity ratio of oil/gas,the producing GOR was converted and normalized into a mass fraction of gas in total hydrocarbons(MGOR) to compare North American shale oil/gas plays with Chinese shale oil and hybrid gas-condensate plays.A correlation between MGOR,the fluid phases,and production data was established to identify five phase stages of flow.MGORvaries systematically with the different production zones,which shows promise in rapidly indicating the well production performance and high production stages of shale oil/gas plays.The hybrid shale gas condensate index,Tmax,and total gas contents were integrated to present the fluid types and maturity of shale gas-condensates,which indicates fluid phase and production variation across thermal evolution.The results offer a unique perspective on the shale oil reservoir producibility based on the impact of GOR on fluid phases and EUR from the dominant global oil/gas plays.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51977027 and 51967008)the Scientific and Technological Project of Yunnan Precious Metals Lab-oratory(Nos.YPML-2023050250 and YPML-2022050206).
文摘The pursuit of Ag-based alloys with both high strength and toughness has posed a longstanding chal-lenge.In this study,we investigated the cluster strengthening and grain refinement toughening mecha-nisms in fully oxidized AgMgNi alloys,which were internally oxidized at 800℃ for 8 h under an oxy-gen atmosphere.We found that Mg-O clusters contributed to the hardening(138 HV)and strengthening(376.9 MPa)of the AgMg alloy through solid solution strengthening effects,albeit at the expense of duc-tility.To address this limitation,we introduced Ni nanoparticles into the AgMg alloy,resulting in signifi-cant grain refinement within its microstructure.Specifically,the grain size decreased from 67.2μm in the oxidized AgMg alloy to below 6.0μm in the oxidized AgMgNi alloy containing 0.3 wt%Ni.Consequently,the toughness increased significantly,rising from toughness value of 2177.9 MJ m^(-3) in the oxidized AgMg alloy to 6186.1 MJ m^(-3) in the oxidized AgMgNi alloy,representing a remarkable 2.8-fold enhancement.Furthermore,the internally oxidized AgMgNi alloy attained a strength of up to 387.6 MPa,comparable to that of the internally oxidized AgMg alloy,thereby demonstrating the successful realization of concurrent strengthening and toughening.These results collectively offer a novel approach for the design of high-performance alloys through the synergistic combination of cluster strengthening and grain refinement toughening.
基金The“13th Five-Year Plan”National Science and Technology Major Project,2016ZX05052,Changchao QiThe China National Petroleum Corporation Science and Technology Project,2021DJ6505,Changchao Qi.
文摘The accuracy and reliability of non-destructive testing(NDT)approaches in detecting interior corrosion problems are critical,yet research in this field is limited.This work describes a novel way to monitor the structural integrity of steel gas pipelines that uses advanced numerical modeling techniques to anticipate fracture development and corrosion effects.The objective is to increase pipeline dependability and safety through more precise,real-time health evaluations.Compared to previous approaches,our solution provides higher accuracy in fault detection and quantification,making it ideal for pipeline integritymonitoring in real-world applications.To solve this issue,statistical analysis was conducted on the size and directional distribution features of about 380,000 sets of internal corrosion faults,as well as simulations of erosion and wear patterns on bent pipes.Using real defectmorphologies,we developed a modeling framework for typical interior corrosion flaws.We evaluated and validated the applicability and effectiveness of in-service inspection processes,as well as conducted on-site comparison tests.The results show that(1)the length and width of corrosion defects follow a log-normal distribution,the clock orientation follows a normal distribution,and the peak depth follows a Freundlich EX function distribution pattern;(2)pipeline corrosion defect data can be classified into three classes using the K-means clustering algorithm,allowing rapid and convenient acquisition of typical size and orientation characteristics of internal corrosion defects;(3)the applicability range and boundary conditions of various NDT techniques were verified,establishing comprehensive selection principles for internal corrosion defect detection technology;(4)on-site inspection results showed a 31%The simulation and validation platform for typical interior corrosion issues greatly enhances the accuracy and reliability of detection data.
基金supported by a postdoctoral project from PetroChina Southwest Oil and Gas Field Company,titled“Research on Flow Behavior of Horizontal Shale Gas Wellbore Based on Reservoir-Wellbore Coupling”(Project Number:2024D103-02-08).
文摘Horizontal wells play a crucial role in enhancing shale gas reservoir production.This study employs transient multiphase simulation to investigate the impact of well trajectory on production optimization throughout a well’s life cycle.The research uses OLGATM as a simulator to examine six well trajectories:toe-up,toe-down,smooth horizontal,undulated toe-up,undulated toe-down,and undulated horizontal.Initial findings indicate comparable production rates across different trajectories during the early production phase,with toe-up wells showing slightly better performances due to minimal slugging.However,as the reservoir pressure decreases,the well trajectory significantly influences production.Horizontal wells achieve the highest accumulated gas production rates due to minimal liquid holdup and back pressure.Toe-up wells experience early liquid accumulation and severe slugging,leading to increased back pressure and smaller production.The study highlights the positive effects of lateral undulations on toe-up and toe-down wells in terms of liquid unloading,however some emphasis is also put on their adverse influence on horizontal wells.
基金financially supported by the National Natural Science Foundation(No.22171212)the National Key Research and Development Program of China(No.2024YFC3908905)+1 种基金the International Exchange Grant(IEC/NSFC/201078)through the Royal Society UK and NSFCTriple boost strategy for low energy consuming catalytic ammonia synthesis(Trimonia)through UK EPSRC UK-HyRES Funding。
文摘Nitrate-to-ammonia conversion presents an effective method to remediate nitrate pollution while transforming waste into a valuable product and has recently garnered significant attention.Beyond the extensively studied Cu-based catalysts,Co has also garnered significant attention.Identifying the real active sites and elucidating the mechanisms are urgently needed for its development in nitrate reduction.Co_(3)O_(4),particularly its Co^(3+)sites,is an established active phase for nitrate reduction and has been extensively studied.However,unlike the deliberate construction of the Co_(3)O_(4)phase or introducing doping to expose more Co^(3+)in the previous studies,it was found in this work that the active species above could be generated in Ni-Co double hydroxides in the context of nitrate reduction.The in situ generated Co_(3)O_(4),especially the spontaneously more exposed octahedrally coordinated Co^(3+),can significantly facilitate the crucial adsorption of Nand thus the following reaction.Furthermore,incorporated Ni sites accelerate nitrate reduction kinetics by promoting hydrogenation,facilitated by their H^(*)-generating capability.This enhanced catalytic activity yields a superior NH_(3)production rate of 7.05 mmol h^(-1)cm^(-2).Besides,a new and more efficient approach for nitrate remediation that focuses on the nitrate sources was proposed and verified through experimentation.
基金financial support for this research by the Australian Research Council (ARC) through the Discovery Project (DP170102557)Future Fellowship (FT160100252)National Health and Medical Research Council (NHMRC), Australia through project grant (GNT1087290)。
文摘Nanolaminates are composed of nanoscale-thick alternating layers of different materials and their properties are dependent on the individual layers,the layer thickness and the interfaces between the layers.Nanolaminates composed of cubic crystal structured metals are usually ductile compared to nanolaminates containing hexagonal crystal structured metals.Mechanical properties such as strength and hardness of nanolaminates increase with a decrease in individual layer thickness down to a few nanometers and they become independent when the thickness of individual layers is less than a couple of nanometers.This review provides a detailed analysis of the effects of individual layer thickness and the interface structures on the strength and the strengthening mecha nisms of nanolaminates,their ductility and fracture behavior in terms of structural variations including grain morphologies,nanotwins,amorphous phases and crystal structures of the layers.The principles for designing nanolaminates with exceptionally high mechanical and physical properties and their fabrication are also highlighted.Some contradictory issues such as strengthening mechanisms,elastic modulus dependency on individual layer thickness and the effect of a thin amorphous layer on the strength are discussed.This review also provides future research directions in designing the high-strength nanolaminates that will facilitate practical engineering applications through analyzing up-to-date research efforts.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51738002 and 52108376)Fundamental Research Funds for the Central Universities (Grant No. 2021CZ111)
文摘Based on the nondestructive test data of operating railway tunnels in China, this paper summarizes the basic characteristics of the complex contact behavior between the rock mass and lining structure. The contact modes are classified into dense contact, local non-contact, and loose contact. Subsequently, the corresponding mechanical model for each contact mode is developed according to its mechanical characteristics using the complex variable method. In the proposed mechanical model, a special algorithm is introduced to detect whether the local non-contact zone is re-contacted. Besides, a novel conformal mapping method is also proposed to accurately calculate the mechanical response of the concrete lining. Finally, the accuracy of the proposed method is verified by comparing it with the finite element method(FEM). Several parameter investigations are conducted to analyze the effects of different contact modes on the rock-lining interaction. The results show that:(i) the height of the local noncontact area does not have a significant effect on the contact stress distribution if no re-contact occurs;(ii) backfill grouting can reduce the local stress concentration caused by poor contact modes;and(iii) reducing the friction coefficient of the interface can lead to a more uniform distribution of internal forces in the concrete lining.
基金financially supported by the National Natural Science Foundation(22171212)the Science and Technology Committee of Shanghai Municipality(21160710300,19DZ2271500)of Chinathe International Exchange Grant(IEC/NSFC/201078)through Royal Society UK and NSFC。
文摘Bimetallic transition metal phosphides(TMPs)as potential candidates for superior electrochemical performance are still facing great challenges in the controllable preparation of two-dimensional(2 D)structures with high aspect ratio.Herein,a novel structure of quasi-monolayered NiCo-bimetal-phosphide(NiCoP)has been designed and successfully synthesized by the newly developed process combined with ultrasonic-cavitation and phase-transition.This is the first time to break through the controllable preparation of 2 D bimetal-phosphides with a thickness of 0.98 nm in sub-nanoscale.Based on the advantages of 2 D quasi-monolayer structure with dense crystalline-amorphous interface and the reconfigured electronic structure between Ni^(δ+)/Co^(δ+)and P^(δ-),the optimized Ni_(5%)CoP exhibits an outstanding bifunctional performance for electrocatalyzing both hydrogen evolution reaction and oxygen evolution reaction in an alkaline medium.Ni_(5%)CoP presents lower overpotentials and voltage of 84 mV&259 mV and1.48 V at the current density of 10 mA cm^(-2)for HER&DER and overall water splitting,respectively,which are superior to most other reported 2 D bimetal-phosphides.This work provides a new strategy to optimize the performance of electrolytic water for bimetal-phosphates and it may be of significant value in extending the design of other ultrathin 2 D structured catalysts.
基金Supported by the National Key Research and Development Program of China(2017YFE0300302)the National Natural Science Foundation of China(21503199,21406212)Key Project of Applied&Basic Research of Sichuan Province(18YYJC1594)
文摘The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum catalysts(Pt/C/PTFE) with high efficiency as reported previously for LPCE were prepared and comprehensive performance evaluation method is applied to evaluate the separation behaviors of LPCE systematically. Experimental results indicate that the optimum reaction temperature of 60–80℃ and the molar feed ratio G/L of 1.5–2.5 would lead to higher separation efficiencies. As to the packing method, a random packing mode with a packing ratio of hydrophobic catalysts 0.25 is recommended. In addition, thermodynamic analysis corresponds well with experimental results under lower temperature and G/L, while the suppression of kinetic factors should not be neglected when T > 80℃ and G/L > 1.5.
基金financially supported by the National Natural Science Foundation of China (Nos.42172140,U2244207,and 42202179)Science Foundation for Distinguished Young Scholars of China University of Petroleum,Beijing (No.2462020QNXZ004)+3 种基金China National Petroleum CorporationChina University of Petroleum (Beijing) Strategic Cooperation Science and Technology Project (No.ZLZX2020-01-06)State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum (No.PRP/open-2217)State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development,the University of Liverpool and China Scholarship Council Awards (No.202009110097)the AAPG Foundation Grants-in-Aid award。
文摘In-situ fluid phase behavior is important in determining hydrocarbon contents and the multiphase flow through shale reservoirs.The gas-to-oil ratio(GOR) has been recognized as a critical indicator of fluid types.However,little is known about the impact of fluid phase variation across the thermal maturity on shale oil/gas production(e.g.,estimated ultimate recovery,EUR).According to the specific gravity ratio of oil/gas,the producing GOR was converted and normalized into a mass fraction of gas in total hydrocarbons(MGOR) to compare North American shale oil/gas plays with Chinese shale oil and hybrid gas-condensate plays.A correlation between MGOR,the fluid phases,and production data was established to identify five phase stages of flow.MGORvaries systematically with the different production zones,which shows promise in rapidly indicating the well production performance and high production stages of shale oil/gas plays.The hybrid shale gas condensate index,Tmax,and total gas contents were integrated to present the fluid types and maturity of shale gas-condensates,which indicates fluid phase and production variation across thermal evolution.The results offer a unique perspective on the shale oil reservoir producibility based on the impact of GOR on fluid phases and EUR from the dominant global oil/gas plays.
