To investigate the evolution of load-bearing characteristics of pre-stressed beams throughout their service life and to provide a basis for accurately assessing the actual working state of damaged pre-stressed concret...To investigate the evolution of load-bearing characteristics of pre-stressed beams throughout their service life and to provide a basis for accurately assessing the actual working state of damaged pre-stressed concrete T-beams,destructive tests were conducted on full-scale pre-stressed concrete beams.Based on the measurement and ana-lysis of beam deflection,strain,and crack development under various loading levels during the research tests,combined with the verification coefficient indicators specified in the codes,the verification coefficients of bridges at different stages of damage can be examined.The results indicate that the T-beams experience complete,incom-plete linear,and non-linear stages during the destructive test process.In the complete linear elastic stage,both the deflection and bottom strain verification coefficients comply with the specifications,indicating a good structural load-bearing capacity no longer adheres to the code’s requirements.In the non-linear stage,both coefficients exhi-bit a sharp increase,resulting in a further decrease in the structure’s load-bearing capacity.According to the pro-visions of the current code,the beam can be in the incomplete linear stage when both values fall within the code’s specified range.The strain verification coefficient sourced from the compression zone at the bottom of theflange is not recommended for assessing the bridge’s load-bearing capacity.展开更多
0 INTRODUCTION Pore-pressure change,which reduces effective normal stress,is a key aftershock trigger,particularly in extensional settings(Miller etal.,2004).Other proposed mechanisms include coseismic stress perturba...0 INTRODUCTION Pore-pressure change,which reduces effective normal stress,is a key aftershock trigger,particularly in extensional settings(Miller etal.,2004).Other proposed mechanisms include coseismic stress perturbations,aseismic slip,and viscoelastic relaxation(Bai et al.,2025;Hu et al.,2025;Perfettini and Avouac,2004;Stein,1999).Determining the dominant mechanism for any event is a critical challenge for understanding regional seismotectonics and assessing evolving hazards.展开更多
Water pollution is an increasingly serious environmental problem because many pollutants have carcinogenic effects on humans and aquatic organisms.Metal organic framework(MOF),made up of metal ions and multifunctional...Water pollution is an increasingly serious environmental problem because many pollutants have carcinogenic effects on humans and aquatic organisms.Metal organic framework(MOF),made up of metal ions and multifunctional organic ligands,has been one of the most concerned materials because of its adjustable and regular pore structure.MOFs have always shown attractive advantages in membrane separation and adsorption technologies,among which water-stable MOFs are particularly prominent in wastewater treatment(WWT)applications.This review systematically summarizes the application of MOF membranes in membrane filtration,membrane pervaporation and membrane distillation.Also,the adsorption mechanisms of heavy metals,dyes and antibacterials in wastewater have been concluded.In order to tap the full application potential of pristine MOFs in sustainable wastewater treatment,current challenges are discussed in detail and future research directions are proposed.展开更多
Timely response to earthquake characterization can facilitate earthquake emergency rescue and further scientific investigations.On June 1,2022,M_(W) 5.9 earthquake occurred in the southern area of the Longmenshan faul...Timely response to earthquake characterization can facilitate earthquake emergency rescue and further scientific investigations.On June 1,2022,M_(W) 5.9 earthquake occurred in the southern area of the Longmenshan fault zone.This event also happened at the south end of the Dayi seismic gap and is the largest earthquake that has occurred in this seismic gap since the 1970 M 6.2 event.The slip-distribution model constrained by the seismic waveforms suggests a thrust-dominated faulting mechanism.The main slip occurs at a depth of~14 km,and the cumulative energy is released in the first 6 s.The variations of Coulomb stress caused by the mainshock show a positive change in the southwest area of the Dayi seismic gap,indicating possible activation of future earthquakes.In addition,we emphasize the importance of rapid estimation of deformation for near-field hazard delineation,especially when interferometric radar fails to image coseismic deformation in a high relief terrain.展开更多
The 2022 M_(W)6.7 Menyuan earthquake ruptured the western end of the Tianzhu seismic gap,providing an opportunity to study the regional seismogenic characteristics and seismic hazards.Here we use interferometric synth...The 2022 M_(W)6.7 Menyuan earthquake ruptured the western end of the Tianzhu seismic gap,providing an opportunity to study the regional seismogenic characteristics and seismic hazards.Here we use interferometric synthetic aperture radar(InSAR)and seismic data to study the mainshock rupture,early afterslip and the second largest aftershock of the 2022 Menyuan earthquake sequences.Our modeling results show that the mainshock ruptured the Lenglongling fault and the Tuolaishan fault with a maximum slip of~3 m.Rapid postseismic transient deformation occurred at the center of the Lenglongling fault.Our afterslip modeling reveals that the majority of afterslip occurred in the deeper part of the Lenglongling fault.A high-angle conjugated faulting event is found at the middle section of the Lenglongling fault.We use the stress inversion to investigate the possible triggering mechanism of the conjugated rupture event.The results indicate the maximum principal stress direction is in~222°,forming a~22°angle between the conjugated fault of second largest aftershock and the mainshock.The calculated normal stress changes indicate the region is within a pull-apart stress field,which favors such a conjugated rupturing event.Our study will help understand the rupture behavior of such kind of conjugated fault in other regions.展开更多
The installation of wind energy has experienced rapid development during recent years.As a result,the operation of power system can be greatly affected.Therefore,the operators of different countries have formulated th...The installation of wind energy has experienced rapid development during recent years.As a result,the operation of power system can be greatly affected.Therefore,the operators of different countries have formulated the grid codes which reinforce technical requirements for wind power plants.In this paper,recent grid codes published in different countries have been carefully reviewed.The basic requirements of active power control and reactive power compensation,both of which have particular influence on wind power plants operation,are focused on.Based on this review,it is understood that with the increasing integration of wind energy,there is a worldwide trend to regulate the performance of wind power plants so that they can contribute to the stability and reliability of power system.展开更多
Metal–organic frameworks(MOFs)are attractive in many fields due to their unique advantages.However,the practical applications of single MOF materials are limited.In recent years,a large number of MOF-based composites...Metal–organic frameworks(MOFs)are attractive in many fields due to their unique advantages.However,the practical applications of single MOF materials are limited.In recent years,a large number of MOF-based composites have been investigated to overcome the defects of single MOF materials to broaden the avenues for the practical applications of MOFs.Among them,MOF-based hybrid nanofiber membranes fabricated by electrospinning combine the advantages of polymer nanofibers and inorganic porous materials,receiving extensive attention and development in energy storage and environmental protection.This review systematically summarizes the recent progress of MOF-based hybrid nanofiber membranes prepared by electrospinning from the perspectives of preparation and application.Firstly,two main methods for preparing MOF/polymer nanofibrous membranes are discussed.Next,the applications of MOF/polymer nanofibrous membranes in energy storage and environmental protection are summarized at length.Finally,to fully tap the potential of MOF-based nanofiber membranes in more fields,the current challenges are proposed,and future research directions are discussed.展开更多
文摘To investigate the evolution of load-bearing characteristics of pre-stressed beams throughout their service life and to provide a basis for accurately assessing the actual working state of damaged pre-stressed concrete T-beams,destructive tests were conducted on full-scale pre-stressed concrete beams.Based on the measurement and ana-lysis of beam deflection,strain,and crack development under various loading levels during the research tests,combined with the verification coefficient indicators specified in the codes,the verification coefficients of bridges at different stages of damage can be examined.The results indicate that the T-beams experience complete,incom-plete linear,and non-linear stages during the destructive test process.In the complete linear elastic stage,both the deflection and bottom strain verification coefficients comply with the specifications,indicating a good structural load-bearing capacity no longer adheres to the code’s requirements.In the non-linear stage,both coefficients exhi-bit a sharp increase,resulting in a further decrease in the structure’s load-bearing capacity.According to the pro-visions of the current code,the beam can be in the incomplete linear stage when both values fall within the code’s specified range.The strain verification coefficient sourced from the compression zone at the bottom of theflange is not recommended for assessing the bridge’s load-bearing capacity.
基金supported by the National Natural Science Foundation of China(Nos.42174023,42030108)the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(No.SKLGP2024Z016)Sichuan Province Science Fund(No.2024NSFSC0802).
文摘0 INTRODUCTION Pore-pressure change,which reduces effective normal stress,is a key aftershock trigger,particularly in extensional settings(Miller etal.,2004).Other proposed mechanisms include coseismic stress perturbations,aseismic slip,and viscoelastic relaxation(Bai et al.,2025;Hu et al.,2025;Perfettini and Avouac,2004;Stein,1999).Determining the dominant mechanism for any event is a critical challenge for understanding regional seismotectonics and assessing evolving hazards.
基金supported by the National Natural Science Foundation of China(NSFC-U1904215)Natural Science Foundation of Jiangsu Province(BK20200044)Changjiang scholars program of the Ministry of Education(Q2018270).
文摘Water pollution is an increasingly serious environmental problem because many pollutants have carcinogenic effects on humans and aquatic organisms.Metal organic framework(MOF),made up of metal ions and multifunctional organic ligands,has been one of the most concerned materials because of its adjustable and regular pore structure.MOFs have always shown attractive advantages in membrane separation and adsorption technologies,among which water-stable MOFs are particularly prominent in wastewater treatment(WWT)applications.This review systematically summarizes the application of MOF membranes in membrane filtration,membrane pervaporation and membrane distillation.Also,the adsorption mechanisms of heavy metals,dyes and antibacterials in wastewater have been concluded.In order to tap the full application potential of pristine MOFs in sustainable wastewater treatment,current challenges are discussed in detail and future research directions are proposed.
基金the National Natural Science Foundation of China(No.42174023)。
文摘Timely response to earthquake characterization can facilitate earthquake emergency rescue and further scientific investigations.On June 1,2022,M_(W) 5.9 earthquake occurred in the southern area of the Longmenshan fault zone.This event also happened at the south end of the Dayi seismic gap and is the largest earthquake that has occurred in this seismic gap since the 1970 M 6.2 event.The slip-distribution model constrained by the seismic waveforms suggests a thrust-dominated faulting mechanism.The main slip occurs at a depth of~14 km,and the cumulative energy is released in the first 6 s.The variations of Coulomb stress caused by the mainshock show a positive change in the southwest area of the Dayi seismic gap,indicating possible activation of future earthquakes.In addition,we emphasize the importance of rapid estimation of deformation for near-field hazard delineation,especially when interferometric radar fails to image coseismic deformation in a high relief terrain.
基金the National Science Fund for Distinguished Young Scholars(No.41925016)National Key Research and Development Program(No.2022YFB3903602)+1 种基金National Natural Science Foundation of China(No.42174023)the Frontier Cross Research Project of Central South University(No.2023QYJC006).
文摘The 2022 M_(W)6.7 Menyuan earthquake ruptured the western end of the Tianzhu seismic gap,providing an opportunity to study the regional seismogenic characteristics and seismic hazards.Here we use interferometric synthetic aperture radar(InSAR)and seismic data to study the mainshock rupture,early afterslip and the second largest aftershock of the 2022 Menyuan earthquake sequences.Our modeling results show that the mainshock ruptured the Lenglongling fault and the Tuolaishan fault with a maximum slip of~3 m.Rapid postseismic transient deformation occurred at the center of the Lenglongling fault.Our afterslip modeling reveals that the majority of afterslip occurred in the deeper part of the Lenglongling fault.A high-angle conjugated faulting event is found at the middle section of the Lenglongling fault.We use the stress inversion to investigate the possible triggering mechanism of the conjugated rupture event.The results indicate the maximum principal stress direction is in~222°,forming a~22°angle between the conjugated fault of second largest aftershock and the mainshock.The calculated normal stress changes indicate the region is within a pull-apart stress field,which favors such a conjugated rupturing event.Our study will help understand the rupture behavior of such kind of conjugated fault in other regions.
文摘The installation of wind energy has experienced rapid development during recent years.As a result,the operation of power system can be greatly affected.Therefore,the operators of different countries have formulated the grid codes which reinforce technical requirements for wind power plants.In this paper,recent grid codes published in different countries have been carefully reviewed.The basic requirements of active power control and reactive power compensation,both of which have particular influence on wind power plants operation,are focused on.Based on this review,it is understood that with the increasing integration of wind energy,there is a worldwide trend to regulate the performance of wind power plants so that they can contribute to the stability and reliability of power system.
基金supported by the National Natural Science Foundation of China(NSFC-U1904215)Natural Science Foundation of Jiangsu Province(BK20200044)Changjiang scholars program of the Ministry of Education(Q2018270).
文摘Metal–organic frameworks(MOFs)are attractive in many fields due to their unique advantages.However,the practical applications of single MOF materials are limited.In recent years,a large number of MOF-based composites have been investigated to overcome the defects of single MOF materials to broaden the avenues for the practical applications of MOFs.Among them,MOF-based hybrid nanofiber membranes fabricated by electrospinning combine the advantages of polymer nanofibers and inorganic porous materials,receiving extensive attention and development in energy storage and environmental protection.This review systematically summarizes the recent progress of MOF-based hybrid nanofiber membranes prepared by electrospinning from the perspectives of preparation and application.Firstly,two main methods for preparing MOF/polymer nanofibrous membranes are discussed.Next,the applications of MOF/polymer nanofibrous membranes in energy storage and environmental protection are summarized at length.Finally,to fully tap the potential of MOF-based nanofiber membranes in more fields,the current challenges are proposed,and future research directions are discussed.
