Digital twin technology,that creates virtual replicas of physical entities using real-time data and simulation models,has emerged as a transformative innovation across multiple healthcare domains.Its application in ph...Digital twin technology,that creates virtual replicas of physical entities using real-time data and simulation models,has emerged as a transformative innovation across multiple healthcare domains.Its application in physiotherapy and rehabilitation represents a paradigm shift from traditional therapeutic approaches to personalized data-driven interventions that optimize patient outcomes.This narrative review examines the current applications,benefits,challenges,and future prospects of digital twin technology in physiotherapy and rehabilitation,providing a comprehensive analysis of the manner in which this technology is reshaping clinical practice and patient care.A narrative review approach was employed,systematically searching PubMed,IEEE Xplore,Scopus,and Web of Science databases.Studies describing digital twin applications,development methodologies,clinical implementations,and theoretical frameworks in physiotherapy and rehabilitation contexts were included.Digital twin technology demonstrates significant potential in personalizing rehabilitation programs,enabling real-time monitoring of patient progress,predicting treatment outcomes,and facilitating remote therapeutic interventions.Current applications span musculoskeletal rehabilitation,neurological recovery,post surgical care,and sports injury management.Key benefits include enhanced treatment precision,improved patient engagement,reduced healthcare costs,and accelerated recovery times.However,implementation faces challenges including technological complexity,data privacy concerns,interoperability issues,and the need for substantial infrastructure investment.Digital twin technology represents a promising frontier in physiotherapy and rehabilitation,offering unprecedented opportunities for personalized,efficient,and effective patient care.Successful integration requires addressing the current limitations while fostering interdisciplinary collaboration between clinicians,engineers,and data scientists.展开更多
Radial jet drilling(RJD)technology is expected to be a technology for the efficient exploitation of geothermal resources.However,the low rock-breaking efficiency is the major obstacle hindering the development of RJD ...Radial jet drilling(RJD)technology is expected to be a technology for the efficient exploitation of geothermal resources.However,the low rock-breaking efficiency is the major obstacle hindering the development of RJD technology.The flow field characteristics and rock breaking ability of cone-straight abrasive jet,rotary abrasive jet,and straight-rotating mixed abrasive jet are analyzed by numerical simulations and experiments.Results show that the axial velocity of the cone-straight abrasive jet is high,the tangential velocity is basically zero,the radial velocity is also small,and the jet impact area is concentrated in the center.A deep hole with a diameter of only 25 mm is formed when the cone-straight abrasive jet breaks the granite.Due to the presence of the guiding impeller,the rotary abrasive jet basically has no axial velocity and has the highest tangential and radial velocity,so it can break the granite to form a hole with a diameter of about 55 mm and a central bulge.The straight-rotating mixed abrasive jet has a large axial/tangential/radial velocity at the same time,so it can break the granite to form a hole with a diameter of about 52 mm with a low bulge.The results show that the straight-rotating mixed abrasive jet combines the advantages of the cone-straight jet and the rotary jet,and is more suitable for the RJD technology.The research results can provide reference for the development of efficient rock-breaking and hole-forming technology,and promote the development of RJD technology in the field of geothermal development.展开更多
Metabolic dysfunction-associated steatotic liver disease(MASLD),recognized as the most prevalent liver disease worldwide and a leading cause of liver transplantation,is closely associated with type 2 diabetes,cardiova...Metabolic dysfunction-associated steatotic liver disease(MASLD),recognized as the most prevalent liver disease worldwide and a leading cause of liver transplantation,is closely associated with type 2 diabetes,cardiovascular disease,and metabolic dysfunction.Its multifactorial pathogenesis involves insulin resistance,lipotoxicity,gut dysbiosis,and dysregulated signaling involving multiple receptors and pathways,culminating in hepatic steatosis,inflammation,fibrosis,and,ultimately,cirrhosis.Emerging insights into bile acid metabolism,shortchain fatty acids,and fibrogenic mediators underscore the complexity of disease progression.Despite increasing global prevalence,effective pharmacological treatments remain limited.Resmetirom,a thyroid hormone receptorβ(THR-β)agonist,is currently the lone agent approved for treating metabolic dysfunctionassociated steatohepatitis(MASH).Off-label use of vitamin E and obeticholic acid has met with some treatment success.Peroxisome proliferator-activated receptor(PPAR)agonists,novel antidiabetic agents,glucagon-like peptide 1 agonists,and sodium-glucose cotransporter 2 inhibitors have shown promising results in MASLD/MASH;however,further data are needed to prove their efficacy and safety.While metformin has largely failed to demonstrate efficacy,hepatotoxicity remains an area of concern with statin therapy.Novel agents,such as fibroblast growth factor analogs,fatty acid synthase inhibitors,galectin-3 inhibitors,and stearoyl-CoA desaturase inhibitors,are in the early stages of development and trials,warranting further research in steatotic liver diseases.Despite encouraging advances,long-term safety,durability of response,and regulatory approvals remain key hurdles before these agents can be broadly implemented in clinical practice.This review summarizes current knowledge on the pathogenesis of MASLD/MASH and the molecular pathways that may offer therapeutic potential in managing this widespread metabolic liver disease.展开更多
Carbon fibres have been produced from hydroxypropyl-modified lignin(TcC)/bio-based polyamide 1010(PA1010)blended filaments.Two grades of PA1010,with different molecular weights and rheological properties,were used for...Carbon fibres have been produced from hydroxypropyl-modified lignin(TcC)/bio-based polyamide 1010(PA1010)blended filaments.Two grades of PA1010,with different molecular weights and rheological properties,were used for blending with TcC.An oxidative thermal stabilisation step was used prior to carbonisation in an inert atmosphere to prevent the fusion of the filaments during the latter step.Thermal stabilisation was not possible using a one-step stabilisation process reported in the literature for lignin and other lignin/synthetic polymer blends.As a consequence,a cyclic process involving an additional isothermal phase at a lower temperature than the precursor filaments’melting point,was introduced to increase the cross-linking reactions between the lignin and polyamide.Thermally stabilised filaments were characterised by DSC,TGA,TGA-FTIR,ATR,and SEM techniques.Polymer rheology and heating rate used during thermal stabilisation influenced the thermal stabilisation process and mechanical properties of the derived filaments.Thermally stabilised filaments using optimised conditions(heating in the air atmosphere at 0.25℃/min to 180℃;isothermal for 1 h,cooling back down to ambient at 5℃/min;heating to 250℃ at 0.25℃/min,isothermal for 2 h)could be successfully carbonised.Carbon fibres pro-duced had void-free morphologies and mechanical properties comparable to similarly thermally stabilised and carbonised polyacrylonitrile(PAN)filaments.展开更多
The globe faces an urgent need to close the energy demand-supply gap.Addressing this difficulty requires constructing a Hybrid Renewable Energy System(HRES),which has proven to be the most appropriate solution.HRES al...The globe faces an urgent need to close the energy demand-supply gap.Addressing this difficulty requires constructing a Hybrid Renewable Energy System(HRES),which has proven to be the most appropriate solution.HRES allows for integrating two or more renewable energy resources,successfully addressing the issue of intermittent availability of non-conventional energy resources.Optimization is critical for improving the HRES’s performance parameters during implementation.This study focuses on HRES using solar and biomass as renewable energy supplies and appropriate energy storage technologies.However,energy fluctuations present a problem with the power quality of HRES.To address this issue,the research paper introduces the Generalized Dynamic Progressive Neural Fuzzy Controller(GDPNFC),which regulates power flow within the proposed HRES.Furthermore,a unique approach called Enhanced Multi-Objective Monarch Butterfly Optimization(EMMBO)is used to optimize technical parameters.The simulation tool used in the research work is HOMER(Hybrid Optimization of Multiple Energy Resources)-PRO,and the system’s power quality is assessed using MATLAB 2016.The research paper concludes with comparing the performance of existing systems to the proposed system in terms of power loss and Total Harmonic Distortion(THD).It was established that the proposed technique involving EMMBO outperformed existing methods in technical optimization.展开更多
Low-permeability heavy oil reservoirs are characterized by poor flowability, generally mandating hydraulic fracturing to commence production. CO_(2) huff-n-puff in fractured reservoirs is an effective enhanced oil rec...Low-permeability heavy oil reservoirs are characterized by poor flowability, generally mandating hydraulic fracturing to commence production. CO_(2) huff-n-puff in fractured reservoirs is an effective enhanced oil recovery method. This paper uses nuclear magnetic resonance imaging to elucidate the role of propped and unpropped fractures on CO_(2) huff-n-puff in cores under different confining pressures. In presence of fractures, significant improvement in the rate of early stage oil recovery is observed, up to 0.255 mL/min. Fractures enlarge the contact area between CO_(2) and the heavy oil, hence improve CO_(2) dissolution and oil flowability. Fractures improve oil recovery from micropores, small pores, and mesopores, as well as reduce CO_(2) consumption ratio. The oil recovery factor in propped fractures is significantly higher than that in unpropped fractures, and with higher oil recovery from small pores and mesopores. The oil recovery in fractured cores noticeably decreases with increasing confining pressure. The extent of fracture closure increases and the matrix pore throats compress under pressure leading to lower apparent permeability. The decrease in oil recovery factor is more pronounced in unpropped fractured cores. A relationship between the apparent permeability of the fracture aperture is derived based on the modified cubic law of percolation to quantitatively characterize the fracture. Additionally, both the reduction in heavy oil viscosity and the increase in experimental temperature and pressure can improve the CO_(2) huff-n-puff oil recovery factor in fractured cores.展开更多
Nano-scale chemical inhomogeneity in surface oxide films formed on a V-and N-containing martensite stainless steel and tempering heating induced changes are investigated by a combination of synchrotron-based hard X-ra...Nano-scale chemical inhomogeneity in surface oxide films formed on a V-and N-containing martensite stainless steel and tempering heating induced changes are investigated by a combination of synchrotron-based hard X-ray Photoelectron emission spectroscopy(HAXPES)and microscopy(HAXPEEM)as well as microscopic X-ray absorption spectroscopy(μ-XAS)techniques.The results reveal the inhomogeneity in the oxide films on the micron-sized Cr_(2)N-and VN-type particles,while the inhomogeneity on the martensite matrix phase exists due to localised formation of nano-sized tempering nitride particles at 600℃.The oxide film formed on Cr_(2)N-type particles is rich in Cr_(2)O_(3) compared with that on the martensite matrix and VN-type particles.With the increase of tempering temperature,Cr_(2)O_(3) formation is faster for the oxidation of Cr in the martensite matrix than the oxidation of Cr nitride-rich particles.展开更多
CO_(2)-responsive gels,which swell upon contact with CO_(2),are widely used for profile control to plug high-permeability gas flow channels in carbon capture,utilization,and storage(CCUS)applications in oil reser-voir...CO_(2)-responsive gels,which swell upon contact with CO_(2),are widely used for profile control to plug high-permeability gas flow channels in carbon capture,utilization,and storage(CCUS)applications in oil reser-voirs.However,the use of these gels in high-temperature CCUS applications is limited due to their rever-sible swelling behavior at elevated temperatures.In this study,a novel dispersed particle gel(DPG)suspension is developed for high-temperature profile control in CCUS applications.First,we synthesize a double-network hydrogel consisting of a crosslinked polyacrylamide(PAAm)network and a crosslinked sodium alginate(SA)network.The hydrogel is then sheared in water to form a pre-prepared DPG suspen-sion.To enhance its performance,the gel particles are modified by introducing potassium methylsilan-etriolate(PMS)upon CO_(2) exposure.Comparing the particle size distributions of the modified and pre-prepared DPG suspension reveals a significant swelling of gel particles,over twice their original size.Moreover,subjecting the new DPG suspension to a 100℃ environment for 24 h demonstrates that its gel particle sizes do not decrease,confirming irreversible swelling,which is a significant advantage over the traditional CO_(2)-responsive gels.Thermogravimetric analysis further indicates improved thermal sta-bility compared to the pre-prepared DPG particles.Core flooding experiments show that the new DPG suspension achieves a high plugging efficiency of 95.3%in plugging an ultra-high permeability sandpack,whereas the pre-prepared DPG suspension achieves only 82.8%.With its high swelling ratio,irreversible swelling at high temperatures,enhanced thermal stability,and superior plugging performance,the newly developed DPG suspension in this work presents a highly promising solution for profile control in high-temperature CCUS applications.展开更多
在传统的丙烯腈-丁二烯-苯乙烯共聚物(ABS)乳液接枝聚合中加入甲基丙烯酸缩水甘油酯(GMA),制得了改性ABS,然后与聚碳酸酯(PC)共混挤出,制得了PC/改性ABS复合材料。结果表明,GMA中的环氧基团能与PC的端羟基和端羧基反应,从而提升合金的...在传统的丙烯腈-丁二烯-苯乙烯共聚物(ABS)乳液接枝聚合中加入甲基丙烯酸缩水甘油酯(GMA),制得了改性ABS,然后与聚碳酸酯(PC)共混挤出,制得了PC/改性ABS复合材料。结果表明,GMA中的环氧基团能与PC的端羟基和端羧基反应,从而提升合金的相容性,且加入10 g GMA制备的改性ABS制作的PC/ABS合金综合性能最好,冲击强度由47 kJ/m^(2)提升到55.5 kJ/m^(2),PC/ABS的断裂伸长率由48%提升到70%。展开更多
Exploration of stable metal single-site supported porous graphitic carbon nitride(PCN)nanostructures and the development of maximum atom utilization for enhanced photocatalytic oxidation of antibiotics remains a chall...Exploration of stable metal single-site supported porous graphitic carbon nitride(PCN)nanostructures and the development of maximum atom utilization for enhanced photocatalytic oxidation of antibiotics remains a challenge in current research.This work proposed a one-step thermal copolymerization to obtain Cu(Ⅰ)doping porous carbon nitride(CUCN)through a spontaneously reducing atmosphere by urea in a covered crucible.The obtained CUCN had crumpled ultrathin nanosheets and mesoporous structures,which possessed higher specific surface areas than PCN.From X-ray absorption near edge structure(XANES)and Fourier transform extended X-ray absorption fine structure(FT-EXAFS)spectra analysis,the Cu doping existed in the oxidation state of Cu(Ⅰ)as single atoms anchored on the 2D layers of CN through two N neighbors,thereby facilitating efficient pathways for the transfer of photoexcited charge carriers.Furthermore,the photoluminescence(PL)spectra,electrochemical impedance spectra(EIS)and transient photocurrent response test proved the improved separation and transfer of photoexcited charge carriers for Cu(Ⅰ)introduction.Consequently,the photocatalytic activity of CUCN was much better than that of PCN for antibiotics norfloxacin(NOR),with 4.7-fold higher degradation reaction rate constants.From species-trapping experiments and density function theory(DFT)calculations,the Cu single atoms in Cu-N_(2)served as catalytic sites that could accelerate charge transfer and facilitate the adsorption of molecular oxygen to produce active species.The stable Cu(Ⅰ)embedded in the layer structure led to the excellent recycling test and remained stable after four runs of degradation and even thermal regenerated treatment.The degradation paths of NOR by CUCN under visible light were also demonstrated.Our work sheds light on a sustainable and practical approach for achieving stable metal single-atom doping and enhancing photocatalytic degradation of aqueous pollutants.展开更多
In order to analyze the pavement stress caused by vehicle bumping at an approach slab, a simplified four-wheeled bi- axle vehicle-moving model is proposed. The effect of damping and vibration reduction in the process ...In order to analyze the pavement stress caused by vehicle bumping at an approach slab, a simplified four-wheeled bi- axle vehicle-moving model is proposed. The effect of damping and vibration reduction in the process of vehicle-moving is not considered. Based on the position change of vehicle wheels at the approach slab, the vehicle dynamic vibration equations are summarized. Meanwhile, the undetermined coefficients of the vibration equations are obtained using the boundary and initial conditions of the vehicle. The analytical motion solutions of rear and front wheels at different stages are concluded. Consequently, a four-wheeled vehicle model is developed and vibration equations are provided, which can be used to analyze the impact of complicated stress on pavement. The results show that the excessive stress and stress concentration will occur at the approach slab, and it needs to be strengthened.展开更多
Conventional manufacturing approaches,including casting,thermal deformation and annealing,have faced great challenges in achieving both exceptional strength and ductility for Mg alloys.Herein,we report an effective st...Conventional manufacturing approaches,including casting,thermal deformation and annealing,have faced great challenges in achieving both exceptional strength and ductility for Mg alloys.Herein,we report an effective strategy for simultaneously enhancing the tensile yield strength(YS=341±9.6 MPa)and elongation(EL=15%±1%)of a Mg-4Sn(at.%)binary alloy at room temperature,which has been prepared by an ultrahigh-pressure treatment followed by Joule-heat treatment(UPJT).More attractively,the aging condition(80µs,500 Hz,600 s)is the most time-efficient mode for aged Mg alloys.The reason is mainly associated with the presence of a unique preferentially-orientated gradient precipitate structure,as confirmed by transmission electron microscopy observations,density functional theory calculations and molecular dynamics simulations.Both experimental and theoretical results demonstrate that twin boundary-induced precipitation followed by precipitate-assisted twin boundary migration accounts for the formation of gradient precipitate structures.The fine Mg_(2)Sn particles can effectively pin dislocation movement to enhance its strength.Comparatively,the coarse Mg_(2)Sn particles can undergo plastic deformation and shear deformation,contributing to its high ductility.The strategy of preferentially orientated gradient structure provides a budding perspective for designing new Mg alloys with superior mechanical properties.展开更多
文摘Digital twin technology,that creates virtual replicas of physical entities using real-time data and simulation models,has emerged as a transformative innovation across multiple healthcare domains.Its application in physiotherapy and rehabilitation represents a paradigm shift from traditional therapeutic approaches to personalized data-driven interventions that optimize patient outcomes.This narrative review examines the current applications,benefits,challenges,and future prospects of digital twin technology in physiotherapy and rehabilitation,providing a comprehensive analysis of the manner in which this technology is reshaping clinical practice and patient care.A narrative review approach was employed,systematically searching PubMed,IEEE Xplore,Scopus,and Web of Science databases.Studies describing digital twin applications,development methodologies,clinical implementations,and theoretical frameworks in physiotherapy and rehabilitation contexts were included.Digital twin technology demonstrates significant potential in personalizing rehabilitation programs,enabling real-time monitoring of patient progress,predicting treatment outcomes,and facilitating remote therapeutic interventions.Current applications span musculoskeletal rehabilitation,neurological recovery,post surgical care,and sports injury management.Key benefits include enhanced treatment precision,improved patient engagement,reduced healthcare costs,and accelerated recovery times.However,implementation faces challenges including technological complexity,data privacy concerns,interoperability issues,and the need for substantial infrastructure investment.Digital twin technology represents a promising frontier in physiotherapy and rehabilitation,offering unprecedented opportunities for personalized,efficient,and effective patient care.Successful integration requires addressing the current limitations while fostering interdisciplinary collaboration between clinicians,engineers,and data scientists.
基金funded by the National Natural Science Foundation of China(No.52374018)Science Foundation of China University of Petroleum,Beijing(No.2462021YJRC009)。
文摘Radial jet drilling(RJD)technology is expected to be a technology for the efficient exploitation of geothermal resources.However,the low rock-breaking efficiency is the major obstacle hindering the development of RJD technology.The flow field characteristics and rock breaking ability of cone-straight abrasive jet,rotary abrasive jet,and straight-rotating mixed abrasive jet are analyzed by numerical simulations and experiments.Results show that the axial velocity of the cone-straight abrasive jet is high,the tangential velocity is basically zero,the radial velocity is also small,and the jet impact area is concentrated in the center.A deep hole with a diameter of only 25 mm is formed when the cone-straight abrasive jet breaks the granite.Due to the presence of the guiding impeller,the rotary abrasive jet basically has no axial velocity and has the highest tangential and radial velocity,so it can break the granite to form a hole with a diameter of about 55 mm and a central bulge.The straight-rotating mixed abrasive jet has a large axial/tangential/radial velocity at the same time,so it can break the granite to form a hole with a diameter of about 52 mm with a low bulge.The results show that the straight-rotating mixed abrasive jet combines the advantages of the cone-straight jet and the rotary jet,and is more suitable for the RJD technology.The research results can provide reference for the development of efficient rock-breaking and hole-forming technology,and promote the development of RJD technology in the field of geothermal development.
文摘Metabolic dysfunction-associated steatotic liver disease(MASLD),recognized as the most prevalent liver disease worldwide and a leading cause of liver transplantation,is closely associated with type 2 diabetes,cardiovascular disease,and metabolic dysfunction.Its multifactorial pathogenesis involves insulin resistance,lipotoxicity,gut dysbiosis,and dysregulated signaling involving multiple receptors and pathways,culminating in hepatic steatosis,inflammation,fibrosis,and,ultimately,cirrhosis.Emerging insights into bile acid metabolism,shortchain fatty acids,and fibrogenic mediators underscore the complexity of disease progression.Despite increasing global prevalence,effective pharmacological treatments remain limited.Resmetirom,a thyroid hormone receptorβ(THR-β)agonist,is currently the lone agent approved for treating metabolic dysfunctionassociated steatohepatitis(MASH).Off-label use of vitamin E and obeticholic acid has met with some treatment success.Peroxisome proliferator-activated receptor(PPAR)agonists,novel antidiabetic agents,glucagon-like peptide 1 agonists,and sodium-glucose cotransporter 2 inhibitors have shown promising results in MASLD/MASH;however,further data are needed to prove their efficacy and safety.While metformin has largely failed to demonstrate efficacy,hepatotoxicity remains an area of concern with statin therapy.Novel agents,such as fibroblast growth factor analogs,fatty acid synthase inhibitors,galectin-3 inhibitors,and stearoyl-CoA desaturase inhibitors,are in the early stages of development and trials,warranting further research in steatotic liver diseases.Despite encouraging advances,long-term safety,durability of response,and regulatory approvals remain key hurdles before these agents can be broadly implemented in clinical practice.This review summarizes current knowledge on the pathogenesis of MASLD/MASH and the molecular pathways that may offer therapeutic potential in managing this widespread metabolic liver disease.
文摘Carbon fibres have been produced from hydroxypropyl-modified lignin(TcC)/bio-based polyamide 1010(PA1010)blended filaments.Two grades of PA1010,with different molecular weights and rheological properties,were used for blending with TcC.An oxidative thermal stabilisation step was used prior to carbonisation in an inert atmosphere to prevent the fusion of the filaments during the latter step.Thermal stabilisation was not possible using a one-step stabilisation process reported in the literature for lignin and other lignin/synthetic polymer blends.As a consequence,a cyclic process involving an additional isothermal phase at a lower temperature than the precursor filaments’melting point,was introduced to increase the cross-linking reactions between the lignin and polyamide.Thermally stabilised filaments were characterised by DSC,TGA,TGA-FTIR,ATR,and SEM techniques.Polymer rheology and heating rate used during thermal stabilisation influenced the thermal stabilisation process and mechanical properties of the derived filaments.Thermally stabilised filaments using optimised conditions(heating in the air atmosphere at 0.25℃/min to 180℃;isothermal for 1 h,cooling back down to ambient at 5℃/min;heating to 250℃ at 0.25℃/min,isothermal for 2 h)could be successfully carbonised.Carbon fibres pro-duced had void-free morphologies and mechanical properties comparable to similarly thermally stabilised and carbonised polyacrylonitrile(PAN)filaments.
文摘The globe faces an urgent need to close the energy demand-supply gap.Addressing this difficulty requires constructing a Hybrid Renewable Energy System(HRES),which has proven to be the most appropriate solution.HRES allows for integrating two or more renewable energy resources,successfully addressing the issue of intermittent availability of non-conventional energy resources.Optimization is critical for improving the HRES’s performance parameters during implementation.This study focuses on HRES using solar and biomass as renewable energy supplies and appropriate energy storage technologies.However,energy fluctuations present a problem with the power quality of HRES.To address this issue,the research paper introduces the Generalized Dynamic Progressive Neural Fuzzy Controller(GDPNFC),which regulates power flow within the proposed HRES.Furthermore,a unique approach called Enhanced Multi-Objective Monarch Butterfly Optimization(EMMBO)is used to optimize technical parameters.The simulation tool used in the research work is HOMER(Hybrid Optimization of Multiple Energy Resources)-PRO,and the system’s power quality is assessed using MATLAB 2016.The research paper concludes with comparing the performance of existing systems to the proposed system in terms of power loss and Total Harmonic Distortion(THD).It was established that the proposed technique involving EMMBO outperformed existing methods in technical optimization.
基金supported by the Open Research Fund of State Key Laboratory of Deep Oil and Gas (No. SKLDOG2024-KFYB-14)the support received from the National Nature Science Foundation of China under Grant No. U20B6003China Scholarship Council (CSC) for financial support
文摘Low-permeability heavy oil reservoirs are characterized by poor flowability, generally mandating hydraulic fracturing to commence production. CO_(2) huff-n-puff in fractured reservoirs is an effective enhanced oil recovery method. This paper uses nuclear magnetic resonance imaging to elucidate the role of propped and unpropped fractures on CO_(2) huff-n-puff in cores under different confining pressures. In presence of fractures, significant improvement in the rate of early stage oil recovery is observed, up to 0.255 mL/min. Fractures enlarge the contact area between CO_(2) and the heavy oil, hence improve CO_(2) dissolution and oil flowability. Fractures improve oil recovery from micropores, small pores, and mesopores, as well as reduce CO_(2) consumption ratio. The oil recovery factor in propped fractures is significantly higher than that in unpropped fractures, and with higher oil recovery from small pores and mesopores. The oil recovery in fractured cores noticeably decreases with increasing confining pressure. The extent of fracture closure increases and the matrix pore throats compress under pressure leading to lower apparent permeability. The decrease in oil recovery factor is more pronounced in unpropped fractured cores. A relationship between the apparent permeability of the fracture aperture is derived based on the modified cubic law of percolation to quantitatively characterize the fracture. Additionally, both the reduction in heavy oil viscosity and the increase in experimental temperature and pressure can improve the CO_(2) huff-n-puff oil recovery factor in fractured cores.
基金supported by the Vinnova(project number 2020-03778)supported by the Swedish Research Council(Vetenskapsradet,project number 2021-04157).
文摘Nano-scale chemical inhomogeneity in surface oxide films formed on a V-and N-containing martensite stainless steel and tempering heating induced changes are investigated by a combination of synchrotron-based hard X-ray Photoelectron emission spectroscopy(HAXPES)and microscopy(HAXPEEM)as well as microscopic X-ray absorption spectroscopy(μ-XAS)techniques.The results reveal the inhomogeneity in the oxide films on the micron-sized Cr_(2)N-and VN-type particles,while the inhomogeneity on the martensite matrix phase exists due to localised formation of nano-sized tempering nitride particles at 600℃.The oxide film formed on Cr_(2)N-type particles is rich in Cr_(2)O_(3) compared with that on the martensite matrix and VN-type particles.With the increase of tempering temperature,Cr_(2)O_(3) formation is faster for the oxidation of Cr in the martensite matrix than the oxidation of Cr nitride-rich particles.
基金Lin Du acknowledges the financial support provided by China Scholarship Council(CSC)via a Ph.D.Scholarship(202008510128)supported by Core Technology Project of China National Petroleum Corporation(CNPC)"Research on Thermal Miscible Flooding Technology"(2023ZG18)。
文摘CO_(2)-responsive gels,which swell upon contact with CO_(2),are widely used for profile control to plug high-permeability gas flow channels in carbon capture,utilization,and storage(CCUS)applications in oil reser-voirs.However,the use of these gels in high-temperature CCUS applications is limited due to their rever-sible swelling behavior at elevated temperatures.In this study,a novel dispersed particle gel(DPG)suspension is developed for high-temperature profile control in CCUS applications.First,we synthesize a double-network hydrogel consisting of a crosslinked polyacrylamide(PAAm)network and a crosslinked sodium alginate(SA)network.The hydrogel is then sheared in water to form a pre-prepared DPG suspen-sion.To enhance its performance,the gel particles are modified by introducing potassium methylsilan-etriolate(PMS)upon CO_(2) exposure.Comparing the particle size distributions of the modified and pre-prepared DPG suspension reveals a significant swelling of gel particles,over twice their original size.Moreover,subjecting the new DPG suspension to a 100℃ environment for 24 h demonstrates that its gel particle sizes do not decrease,confirming irreversible swelling,which is a significant advantage over the traditional CO_(2)-responsive gels.Thermogravimetric analysis further indicates improved thermal sta-bility compared to the pre-prepared DPG particles.Core flooding experiments show that the new DPG suspension achieves a high plugging efficiency of 95.3%in plugging an ultra-high permeability sandpack,whereas the pre-prepared DPG suspension achieves only 82.8%.With its high swelling ratio,irreversible swelling at high temperatures,enhanced thermal stability,and superior plugging performance,the newly developed DPG suspension in this work presents a highly promising solution for profile control in high-temperature CCUS applications.
文摘在传统的丙烯腈-丁二烯-苯乙烯共聚物(ABS)乳液接枝聚合中加入甲基丙烯酸缩水甘油酯(GMA),制得了改性ABS,然后与聚碳酸酯(PC)共混挤出,制得了PC/改性ABS复合材料。结果表明,GMA中的环氧基团能与PC的端羟基和端羧基反应,从而提升合金的相容性,且加入10 g GMA制备的改性ABS制作的PC/ABS合金综合性能最好,冲击强度由47 kJ/m^(2)提升到55.5 kJ/m^(2),PC/ABS的断裂伸长率由48%提升到70%。
基金supported by the National Natural Science Foundation of China(Nos.52070103 and 22102102)Zhejiang Provincial Natural Science Foundation of China(Nos.LY21E090004 and LQ22B050004)+1 种基金Ningbo Public Welfare Science and Technology Program(No.2021S025)Ningbo Youth Leading Talent Project(No.2024QL038).
文摘Exploration of stable metal single-site supported porous graphitic carbon nitride(PCN)nanostructures and the development of maximum atom utilization for enhanced photocatalytic oxidation of antibiotics remains a challenge in current research.This work proposed a one-step thermal copolymerization to obtain Cu(Ⅰ)doping porous carbon nitride(CUCN)through a spontaneously reducing atmosphere by urea in a covered crucible.The obtained CUCN had crumpled ultrathin nanosheets and mesoporous structures,which possessed higher specific surface areas than PCN.From X-ray absorption near edge structure(XANES)and Fourier transform extended X-ray absorption fine structure(FT-EXAFS)spectra analysis,the Cu doping existed in the oxidation state of Cu(Ⅰ)as single atoms anchored on the 2D layers of CN through two N neighbors,thereby facilitating efficient pathways for the transfer of photoexcited charge carriers.Furthermore,the photoluminescence(PL)spectra,electrochemical impedance spectra(EIS)and transient photocurrent response test proved the improved separation and transfer of photoexcited charge carriers for Cu(Ⅰ)introduction.Consequently,the photocatalytic activity of CUCN was much better than that of PCN for antibiotics norfloxacin(NOR),with 4.7-fold higher degradation reaction rate constants.From species-trapping experiments and density function theory(DFT)calculations,the Cu single atoms in Cu-N_(2)served as catalytic sites that could accelerate charge transfer and facilitate the adsorption of molecular oxygen to produce active species.The stable Cu(Ⅰ)embedded in the layer structure led to the excellent recycling test and remained stable after four runs of degradation and even thermal regenerated treatment.The degradation paths of NOR by CUCN under visible light were also demonstrated.Our work sheds light on a sustainable and practical approach for achieving stable metal single-atom doping and enhancing photocatalytic degradation of aqueous pollutants.
基金The Doctoral Program of Central South University (No. 2010ybfz048)the National High Technology Research and Development Program of China (863 Program) (No. 2007AA021908)
文摘In order to analyze the pavement stress caused by vehicle bumping at an approach slab, a simplified four-wheeled bi- axle vehicle-moving model is proposed. The effect of damping and vibration reduction in the process of vehicle-moving is not considered. Based on the position change of vehicle wheels at the approach slab, the vehicle dynamic vibration equations are summarized. Meanwhile, the undetermined coefficients of the vibration equations are obtained using the boundary and initial conditions of the vehicle. The analytical motion solutions of rear and front wheels at different stages are concluded. Consequently, a four-wheeled vehicle model is developed and vibration equations are provided, which can be used to analyze the impact of complicated stress on pavement. The results show that the excessive stress and stress concentration will occur at the approach slab, and it needs to be strengthened.
基金supported by National Science Foundation of China(Nos.52331003,52171126 and 52202374)the Natural Science Foundation of Hebei Province(Nos.E2022203167,E2023203255 and 236Z1020G)+1 种基金Innovation Groups Program(No.C2022203003)the Ministry of Education Yangtze River Scholar Professor Program(No.T2020124).
文摘Conventional manufacturing approaches,including casting,thermal deformation and annealing,have faced great challenges in achieving both exceptional strength and ductility for Mg alloys.Herein,we report an effective strategy for simultaneously enhancing the tensile yield strength(YS=341±9.6 MPa)and elongation(EL=15%±1%)of a Mg-4Sn(at.%)binary alloy at room temperature,which has been prepared by an ultrahigh-pressure treatment followed by Joule-heat treatment(UPJT).More attractively,the aging condition(80µs,500 Hz,600 s)is the most time-efficient mode for aged Mg alloys.The reason is mainly associated with the presence of a unique preferentially-orientated gradient precipitate structure,as confirmed by transmission electron microscopy observations,density functional theory calculations and molecular dynamics simulations.Both experimental and theoretical results demonstrate that twin boundary-induced precipitation followed by precipitate-assisted twin boundary migration accounts for the formation of gradient precipitate structures.The fine Mg_(2)Sn particles can effectively pin dislocation movement to enhance its strength.Comparatively,the coarse Mg_(2)Sn particles can undergo plastic deformation and shear deformation,contributing to its high ductility.The strategy of preferentially orientated gradient structure provides a budding perspective for designing new Mg alloys with superior mechanical properties.
