Microsoft Direct Show是微软Windows平台中的SDK的重要组成部分,是一款新推出的基于Direct X和COM技术的多媒体应用程序开发包,可以很方便地开发出具备高性能和高质量要求的多媒体应用程序,是未来多媒体应用程序的开发方向。本文将从Di...Microsoft Direct Show是微软Windows平台中的SDK的重要组成部分,是一款新推出的基于Direct X和COM技术的多媒体应用程序开发包,可以很方便地开发出具备高性能和高质量要求的多媒体应用程序,是未来多媒体应用程序的开发方向。本文将从Direct Show的基本结构出发,分析和探讨Microsoft Direct Show的平台程序使用方法。展开更多
High-resolution non-emissive displays based on electrochromic tungsten oxides(WOx)are crucial for future near-eye virtual/augmented reality interactions,given their impressive attributes such as high environmental sta...High-resolution non-emissive displays based on electrochromic tungsten oxides(WOx)are crucial for future near-eye virtual/augmented reality interactions,given their impressive attributes such as high environmental stability,ideal outdoor readability,and low energy consumption.However,the limited intrinsic structure of inorganic materials has presented a significant challenge in achieving precise patterning/pixelation at the micron scale.Here,we successfully developed the direct photolithography for WOx nanoparticles based on in situ photo-induced ligand exchange.This strategy enabled us to achieve ultra-high resolution efficiently(line width<4μm,the best resolution for reported inorganic electrochromic materials).Additionally,the resulting device exhibited impressive electrochromic performance,such as fast response(<1 s at 0 V),high coloration efficiency(119.5 cm^(2) C^(−1)),good optical modulation(55.9%),and durability(>3600 cycles),as well as promising applications in electronic logos,pixelated displays,flexible electronics,etc.The success and advancements presented here are expected to inspire and accelerate research and development(R&D)in high-resolution non-emissive displays and other ultra-fine micro-electronics.展开更多
With the approaching of large-scale retirement of power lithium-ion batteries(LIBs),their urgent handling is required for environmental protection and resource reutilization.However,at present,substantial spent power ...With the approaching of large-scale retirement of power lithium-ion batteries(LIBs),their urgent handling is required for environmental protection and resource reutilization.However,at present,substantial spent power batteries,especially for those high recovery value cathode materials,have not been greenly,sustainably,and efficiently recycled.Compared to the traditional recovery method for cathode materials with high energy consumption and severe secondary pollution,the direct repair regeneration,as a new type of short-process and efficient treatment methods,has attracted widespread attention.However,it still faces challenges in homogenization repair,electrochemical performance decline,and scaling-up production.To promote the direct regeneration technology development of failed NCM materials,herein we deeply discuss the failure mechanism of nickel-cobalt-manganese(NCM)ternary cathode materials,including element loss,Li/Ni mixing,phase transformation,structural defects,oxygen release,and surface degradation and reconstruction.Based on this,the detailed analysis and summary of the direct regeneration method embracing solid-phase sintering,eutectic salt assistance,solvothermal synthesis,sol-gel process,spray drying,and redox mediation are provided.Further,the upcycling strategy for regeneration materials,such as single-crystallization and high-nickelization,structural regulation,ion doping,and surface engineering,are discussed in deep.Finally,the challenges faced by the direct regeneration and corresponding countermeasures are pointed out.Undoubtedly,this review provides valuable guidance for the efficient and high-value recovery of failed cathode materials.展开更多
Developing deep fragmented soft coalbed methane(CBM)can significantly enhance domestic natural gas supplies,reduce reliance on imported energy,and bolster national energy security.This manuscript provides a comprehens...Developing deep fragmented soft coalbed methane(CBM)can significantly enhance domestic natural gas supplies,reduce reliance on imported energy,and bolster national energy security.This manuscript provides a comprehensive review of commonly employed coalbed methane extraction technologies.It then delves into several critical issues in the current stage of CBM exploration and development in China,including the compatibility of existing technologies with CBM reservoirs,the characteristics and occurrence states of CBM reservoirs,critical desorption pressure,and gas generation mechanisms.Our research indicates that current CBM exploration and development technologies in China have reached an internationally advanced level,yet the industry is facing unprecedented challenges.Despite progress in low-permeability,high-value coal seams,significant breakthroughs have not been achieved in exploring other types of coal seams.For different coal reservoirs,integrated extraction technologies have been developed,such as surface pre-depressurisation and segmented hydraulic fracturing of coal seam roof strata.Additionally,techniques like large-scale volume fracturing in horizontal wells have been established,significantly enhancing reservoir stimulation effects and coalbed methane recovery rates.However,all of these technologies are fundamentally based on permeation.These technologies lack direct methods aimed at enhancing the diffusion rate of CBM,thereby failing to fully reflect the unique characteristics of CBM.Current CBM exploration and development theories and technologies are not universally applicable to all coal seams.They do not adequately account for the predominantly adsorbed state of CBM,and the complex and variable gas generation mechanisms further constrain CBM development in China.Finally,continuous exploration of new deep CBM exploration technologies is necessary.Integrating more effective reservoir stimulation technologies is essential to enhance technical adaptability concerning CBM reservoir characteristics,gas occurrence states,and gas generation mechanisms,ultimately achieving efficient CBM development.We conclude that while China possesses a substantial foundation of deep fractured CBM resources,industry development is constrained and requires continuous exploration of new CBM exploration and development technologies to utilize these resources effectively.展开更多
Large-scale deployment of carbon dioxide(CO_(2))removal technology is an essential step to cope with global warming and achieve carbon neutrality.Direct air capture(DAC)has recently received increasing attention given...Large-scale deployment of carbon dioxide(CO_(2))removal technology is an essential step to cope with global warming and achieve carbon neutrality.Direct air capture(DAC)has recently received increasing attention given the high flexibility to remove CO_(2)from discrete sources.Porous materials with adjustable pore characteristics are promising sorbents with low or no latent heat of vaporization.This review article has summarized the recent development of porous sorbents for DAC,with a focus of pore engineering strategy and adsorption mechanism.Physisorbents such as zeolites,porous carbons,metal-organic frameworks(MOFs),and amine-modified chemisorbents have been discussed and their challenges in practical application have been analyzed.At last,future directions have been proposed,and it is expected to inspire collaborations from chemistry,environment,material science and engineering communities.展开更多
The layer-by-layer deposition strategy of additive manufacturing makes it ideal to fabricate dissimilar alloy components with varying functionality,which has promising application potential in a large number of indust...The layer-by-layer deposition strategy of additive manufacturing makes it ideal to fabricate dissimilar alloy components with varying functionality,which has promising application potential in a large number of industrial areas.In this study,two components composed of ERCuAl-A2 aluminum bronze(CuAl9)and Inconel 718 nickel-based superalloy were fabricated with different deposition orders by wire-arc directed energy deposition.Subject to changes in heat input and thermophysical properties of the substrate,the transition region of the deposited Cu-Ni component with the bottom half of CuAl9 and the top half of Inconel 718 is narrow and serrated.This region features a laminated intermetallic compound layer due to the convection and rapid cooling in the molten pool.In contrast,the Ni-Cu component deposited in the opposite order exhibits a 2 mm gradient transition zone.Within this region,a large number of diverse precipitates were found as well as regional variations in grain size due to the multi-layer partial remelting.Both two components show strong bonds and their tensile specimens tested along the vertical direction always fracture at the softer CuAl9 side.Excellent tensile properties along the horizontal direction were obtained for Cu-Ni(Ultimate tensile strength:573 MPa,yield stress:302 MPa,elongation:22%),while those of Ni-Cu are much lower due to the existence of the solidification cracks in the transition zone.The results from this study provide a reference for the additive manufacturing of Cu/Ni dissimilar alloy components,as well as their microstructure and mechanical properties control.展开更多
For realizing the goals of“carbon peak”and“carbon neutrality”,lithium-ion batteries(LIB)with LiFePO_(4)as the cathode material have been widely applied.However,this has also led to a large number of spent lithium-...For realizing the goals of“carbon peak”and“carbon neutrality”,lithium-ion batteries(LIB)with LiFePO_(4)as the cathode material have been widely applied.However,this has also led to a large number of spent lithium-ion batteries,and the safe disposal of spent lithium-ion batteries is an urgent issue.Currently,the main reason for the capacity decay of LiFePO_(4)materials is the Li deficiency and the formation of the Fe^(3+)phase.In order to address this issue,we performed high-temperature calcination of the discarded lithium iron phosphate cathode material in a carbon dioxide environment to reduce or partially remove the carbon coating on its surface.Subsequently,mechanical grinding was conducted to ensure thorough mixing of the lithium source with the discarded lithium iron phosphate.The reaction between CO_(2)and the carbon coating produced a reducing atmosphere,reducing Fe^(3+)to Fe^(2+)and thereby reducing the content of Fe^(3+).The Fe^(3+)content in the repaired LiFePO_(4)material is reduced.The crystal structure of spent LiFePO_(4)cathode materials was repaired more completely compare with the traditional pretreatment method,and the repaired LiFePO_(4)material shows good electrochemical performance and cycling stability.Under 0.1 C conditions,the initial capacity can reach 149.1 m Ah/g.It can be reintroduced for commercial use.展开更多
Aiming at mitigating the high risks associated with conventional explosive blasting,this study developed a safe directional fracturing technique,i.e.instantaneous expansion with a single fracture(IESF),using a coal-ba...Aiming at mitigating the high risks associated with conventional explosive blasting,this study developed a safe directional fracturing technique,i.e.instantaneous expansion with a single fracture(IESF),using a coal-based solid waste expanding agent.First,the mechanism of directional fracturing blasting by the IESF was analyzed,and the criterion of directional crack initiation was established.On this basis,laboratory experiments and numerical simulations were conducted to systematically evaluate the directional fracturing blasting performance of the IESF.The results indicate that the IESF presents an excellent directional fracturing effect,with average surface undulation differences ranging from 8.1 mm to 22.7 mm on the fracture surfaces.Moreover,during concrete fracturing tests,the stresses and strains in the fracturing direction are measured to be 2.16-3.71 times and 8 times larger than those in the nonfracturing direction,respectively.Finally,the IESF technique was implemented for no-pillar mining with gob-side entry retaining through roof cutting and pressure relief in an underground coal mine.The IESF technique effectively created directional cracks in the roof without causing severe roadway deformation,achieving an average cutting rate and maximum roadway deformation of 94%and 197 mm,respectively.These on-site test results verified its excellent directional rock fracturing performance.The IESF technique,which is safe,efficient,and green,has considerable application prospects in the field of rock mechanics and engineering.展开更多
Solution and aging treatment were conducted on the laser directed energy deposition(LDED)-prepared carbon nanotubes(CNTs)-reinforced WE43(CNTs/WE43)layers to optimize their microstructure and surface properties in thi...Solution and aging treatment were conducted on the laser directed energy deposition(LDED)-prepared carbon nanotubes(CNTs)-reinforced WE43(CNTs/WE43)layers to optimize their microstructure and surface properties in this study.The microstructure of the WE43 and CNTs/WE43 layers was systematically compared.The dissolution of divorced eutectics at the grain boundaries was retarded by CNTs during solution treatment.The spot segregation composed of Mg_(24)Y_(5),CNTs,and Zr cores in the solution treated CNTs/WE43 layer presented a slight decreasing in Y content.The grain growth of both types of layers underwent three stages:slow,rapid,and steady-state.The significant inhibitory effect of CNTs on the grain growth of the LDED WE43 matrix was more pronounced than the promoting effect of temperature,resulting in a 47%increase at 510℃ and a 35%increase at 540℃ in the grain growth exponent compared to the WE43 layers at 510℃.During the subsequent aging treatment at 225℃,the precipitation sequences from plate-shaped β″to plate-shaped and globular β′ were observed in both types of layers.CNTs can facilitate an increase in the nucleation rate of precipitates,but without accelerating precipitation hardening rate.The long and short diameters of the precipitates in peak-aged state were decreased by 48.5%and 43.1%by addition of CNTs,respectively.The wear resistance of both the WE43 and CNTs/WE43 layers can be significantly enhanced through solution and aging treatment.The enhancement in wear resistance for the CNTs/WE43 layers is considerably greater than that of the WE43 layers.展开更多
Understanding the mesoscopic tensile fracture damage of rock is the basis of evaluating the deterioration process of mechanical properties of heat-damaged rock. For this, tensile tests of rocks under high-temperature ...Understanding the mesoscopic tensile fracture damage of rock is the basis of evaluating the deterioration process of mechanical properties of heat-damaged rock. For this, tensile tests of rocks under high-temperature treatment were conducted with a ϕ75 mm split Hopkinson tension bar (SHTB) to investigate the mesoscopic fracture and damage properties of rock. An improved scanning electron microscopy (SEM) experimental method was used to analyze the tensile fracture surfaces of rock samples. Qualitative and quantitative analyses were performed to assess evolution of mesoscopic damage of heat-damaged rock under tensile loading. A constitutive model describing the mesoscopic fractal damage under thermo-mechanical coupling was established. The results showed that the high temperatures significantly reduced the tensile strength and fracture surface roughness of the red sandstone. The three-dimensional (3D) reconstruction of the fracture surface of the samples that experienced tensile failure at 900 °C showed a flat surface. The standard deviation of elevation and slope angle of specimen fracture surface first increased and then decreased with increasing temperature. The threshold for brittle fracture of the heat-damaged red sandstone specimens was 600 °C. Beyond this threshold temperature, local ductile fracture occurred, resulting in plastic deformation of the fracture surface during tensile fracturing. With increase of temperature, the internal meso-structure of samples was strengthened slightly at first and then deteriorated gradually, which was consistent with the change of macroscopic mechanical properties of red sandstone. The mesoscopic characteristics, such as the number, mean side length, maximum area, porosity, and fractal dimension of crack, exhibited an initial decline, followed by a gradual increase. The development of microcracks in samples had significant influence on mesoscopic fractal dimension. The mesoscopic fractal characteristics were used to establish a mesoscopic fractal damage constitutive model for red sandstone, and the agreement between the theoretical and experimental results validated the proposed model.展开更多
Among the synthesis techniques for graphene,chemical vapor deposition(CVD)enables the direct growth of graphene films on insulating substrates.Its advantages include uniform coverage,high quality,scalability,and compa...Among the synthesis techniques for graphene,chemical vapor deposition(CVD)enables the direct growth of graphene films on insulating substrates.Its advantages include uniform coverage,high quality,scalability,and compatibility with industrial processes.Graphene is chemically inert and has a zero-bandgap which poses a problem for its use as a functional layer,and nitrogen doping has become an important way to overcome this.Post-plasma treatment has been explored for the synthesis of nitrogen-doped graphene,but the procedures are intricate and not suitable for large-scale production.We report the direct synthesis of nitrogen-doped graphene on a 4-inch sapphire wafer by ethanol-assisted CVD employing pyridine as the carbon feedstock,where the nitrogen comes from the pyridine and the hydroxyl group in ethanol improves the quality of the graphene produced.Additionally,the types of nitrogen dopant produced and their effects on III-nitride epitaxy were also investigated,resulting in the successful illumination of LED devices.This work presents an effective synthesis strategy for the preparation of nitrogen-doped graphene,and provides a foundation for designing graphene functional layers in optoelectronic devices.展开更多
Direct ethanol fuel cells(DEFCs)are a promising alternative to conventional energy sources,offering high energy density,environmental sustainability,and operational safety.Compared to methanol fuel cells,DEFCs exhibit...Direct ethanol fuel cells(DEFCs)are a promising alternative to conventional energy sources,offering high energy density,environmental sustainability,and operational safety.Compared to methanol fuel cells,DEFCs exhibit lower toxicity and a more mature preparation process.Unlike hydrogen fuel cells,DEFCs provide superior storage and transport feasibility,as well as cost-effectiveness,significantly enhancing their commercial viability.However,the stable C-C bond in ethanol creates a high activation energy barrier,often resulting in incomplete electrooxidation.Current commercial platinum(Pt)-and palladium(Pd)-based catalysts demonstrate low C-C bond cleavage efficiency(<7.5%),severely limiting DEFC energy output and power density.Furthermore,high catalyst costs and insufficient activity impede large-scale commercialization.Recent advances in DEFC anode catalyst design have focused on optimizing material composition and elucidating catalytic mechanisms.This review systematically examines developments in ethanol electrooxidation catalysts over the past five years,highlighting strategies to improve C1 pathway selectivity and C-C bond activation.Key approaches,such as alloying,nanostructure engineering,and interfacial synergy effects,are discussed alongside their mechanistic implications.Finally,we outline current challenges and future prospects for DEFC commercialization.展开更多
Professor Paul Crosthwaite,from the School of Literature,Languages,and Cultures at the University of Edinburgh,is a prominent scholar in the interdisciplinary field of literature and economics.He is a co-editor of the...Professor Paul Crosthwaite,from the School of Literature,Languages,and Cultures at the University of Edinburgh,is a prominent scholar in the interdisciplinary field of literature and economics.He is a co-editor of the Palgrave Studies in Literature,Culture,and Economics series and The Cambridge Companion to Literature and Economics(2022).In recent years,he has significantly influenced the intersection of literature and economics,advocating particularly for a shift towards the Economic Humanities.This interview covers:1.The definition and theoretical origin of the Economic Humanities;2.The internal heterogeneity and critical limitations of the New Economic Criticism,and the theoretical advantages and potential development of the Economic Humanities;3.What research paradigms do Environmental Humanities,Medical Humanities,and Digital Humanities provide for the Economic Humanities;4.How literary researchers can work at the interface of the Economic Humanities research.As a novel interdisciplinary interface between literature and economics,Professor Paul Crosthwaite’s concept of the Economic Humanities not only pioneers methodological tools for interdisciplinary studies of literature and economics but also underscores the interpretative potential and disciplinary benefits of literary viewpoints on economics.This underscores the vital role of literature in human knowledge,meriting attention from the literary research academia.展开更多
Plant roots are widely known to provide mechanical reinforcement to soils against shearing and further increase slope stability.However,whether roots provide reinforcement to loess cyclic re-sistance and how various f...Plant roots are widely known to provide mechanical reinforcement to soils against shearing and further increase slope stability.However,whether roots provide reinforcement to loess cyclic re-sistance and how various factors affect roots reinforcement during seismic loading have rarely been studied.The objective is to conduct a series of cyclic direct simple shear tests and DEM numerical simulation to investigate the cyclic behaviour of rooted loess.The effects of initial static shear stress and loading frequency on the cyclic resistance of root-soil composites were first investigated.After that,cyclic direct simple shear simulations at constant volume were carried out based on the discrete element method(PFC^(3D))to investigate the effects of root geome-try,mechanical traits and root-soil bond strength on the cyclic strength of rooted loess.It was discovered that the roots could effectively improve the cyclic resistance of loess.The cyclic resistance of the root-soil composite decreases with the increase of the initial shear stress,then increases,and improves with the increase of the frequency.The simulation result show that increases in root elastic modulus and root-soil interfacial bond strength can all enhance the cyclic resistance of root-soil composites,and the maximum cyclic resistance of the root-soil composite was obtained when the initial inclination angle of the root system was 90°.展开更多
Aiming at the problem that infrared small target detection faces low contrast between the background and the target and insufficient noise suppression ability under the complex cloud background,an infrared small targe...Aiming at the problem that infrared small target detection faces low contrast between the background and the target and insufficient noise suppression ability under the complex cloud background,an infrared small target detection method based on the tensor nuclear norm and direction residual weighting was proposed.Based on converting the infrared image into an infrared patch tensor model,from the perspective of the low-rank nature of the background tensor,and taking advantage of the difference in contrast between the background and the target in different directions,we designed a double-neighborhood local contrast based on direction residual weighting method(DNLCDRW)combined with the partial sum of tensor nuclear norm(PSTNN)to achieve effective background suppression and recovery of infrared small targets.Experiments show that the algorithm is effective in suppressing the background and improving the detection ability of the target.展开更多
The integration of large-scale new energy and high-capacity DC transmission leads to a reduction in system inertia.Grid-forming renewable energy sources(GF-RES)has a significant improvement effect on system inertia.Co...The integration of large-scale new energy and high-capacity DC transmission leads to a reduction in system inertia.Grid-forming renewable energy sources(GF-RES)has a significant improvement effect on system inertia.Commutation failure faults may cause a short-term reactive power surplus at the sending end and trigger transient overvoltage,threatening the safe and stable operation of the power grid.However,there is a lack of research on the calculation method of transient overvoltage caused by commutation failure in high-voltage DC transmission systems with grid-forming renewable energy sources integration.Based on the existing equivalent model of highvoltage DC transmission systems at the sending end,this paper proposes to construct a model of the high-voltage DC transmission system at the sending end with grid-forming renewable energy sources.The paper first clarifies the mechanism of overvoltage generation,then considers the reactive power droop control characteristics of GF-RES,and derives the transient voltage calculation model of theDC transmission system with GF-RES integration.It also proposes a calculation method for transient overvoltage at the sending-end converter bus with GF-RES integration.Based on the PSCAD/EMTDC simulation platform,this paper builds an experimental simulation model.By constructing three different experimental scenarios,the accuracy and effectiveness of the proposed transient overvoltage calculation method are verified,with a calculation error within 5%.At the same time,this paper quantitatively analyzes the impact of grid strength,new energy proportion,and rated transmission power on transient overvoltage from three different perspectives.展开更多
文摘Microsoft Direct Show是微软Windows平台中的SDK的重要组成部分,是一款新推出的基于Direct X和COM技术的多媒体应用程序开发包,可以很方便地开发出具备高性能和高质量要求的多媒体应用程序,是未来多媒体应用程序的开发方向。本文将从Direct Show的基本结构出发,分析和探讨Microsoft Direct Show的平台程序使用方法。
基金supported by the National Key R&D Program of China(2022YFB3606501,2022YFB3602902)the Key projects of National Natural Science Foundation of China(62234004)+8 种基金the National Natural Science Foundation of China(U23A2092)Pioneer and Leading Goose R&D Program of Zhejiang(2024C01191,2024C01092)Innovation and Entrepreneurship Team of Zhejiang Province(2021R01003)Ningbo Key Technologies R&D Program(2022Z085),Ningbo 3315 Programme(2020A-01-B)YONGJIANG Talent Introduction Programme(2021A-038-B,2021A-159-G)“Innovation Yongjiang 2035”Key R&D Programme(2024Z146)Ningbo JiangBei District public welfare science and technology project(2022C07)the China National Postdoctoral Program for Innovative Talents(grant no.BX20240391)the China Postdoctoral Science Foundation(grant no.2023M743623).
文摘High-resolution non-emissive displays based on electrochromic tungsten oxides(WOx)are crucial for future near-eye virtual/augmented reality interactions,given their impressive attributes such as high environmental stability,ideal outdoor readability,and low energy consumption.However,the limited intrinsic structure of inorganic materials has presented a significant challenge in achieving precise patterning/pixelation at the micron scale.Here,we successfully developed the direct photolithography for WOx nanoparticles based on in situ photo-induced ligand exchange.This strategy enabled us to achieve ultra-high resolution efficiently(line width<4μm,the best resolution for reported inorganic electrochromic materials).Additionally,the resulting device exhibited impressive electrochromic performance,such as fast response(<1 s at 0 V),high coloration efficiency(119.5 cm^(2) C^(−1)),good optical modulation(55.9%),and durability(>3600 cycles),as well as promising applications in electronic logos,pixelated displays,flexible electronics,etc.The success and advancements presented here are expected to inspire and accelerate research and development(R&D)in high-resolution non-emissive displays and other ultra-fine micro-electronics.
基金financially supported by the National Key Research and Development Program of China(2023YFB3809300)。
文摘With the approaching of large-scale retirement of power lithium-ion batteries(LIBs),their urgent handling is required for environmental protection and resource reutilization.However,at present,substantial spent power batteries,especially for those high recovery value cathode materials,have not been greenly,sustainably,and efficiently recycled.Compared to the traditional recovery method for cathode materials with high energy consumption and severe secondary pollution,the direct repair regeneration,as a new type of short-process and efficient treatment methods,has attracted widespread attention.However,it still faces challenges in homogenization repair,electrochemical performance decline,and scaling-up production.To promote the direct regeneration technology development of failed NCM materials,herein we deeply discuss the failure mechanism of nickel-cobalt-manganese(NCM)ternary cathode materials,including element loss,Li/Ni mixing,phase transformation,structural defects,oxygen release,and surface degradation and reconstruction.Based on this,the detailed analysis and summary of the direct regeneration method embracing solid-phase sintering,eutectic salt assistance,solvothermal synthesis,sol-gel process,spray drying,and redox mediation are provided.Further,the upcycling strategy for regeneration materials,such as single-crystallization and high-nickelization,structural regulation,ion doping,and surface engineering,are discussed in deep.Finally,the challenges faced by the direct regeneration and corresponding countermeasures are pointed out.Undoubtedly,this review provides valuable guidance for the efficient and high-value recovery of failed cathode materials.
基金supported by the National Natural Science Foundation of China(52074045,52274074)the Science Fund for Distinguished Young Scholars of Chongqing(CSTB2022NSCQ-JQX0028).
文摘Developing deep fragmented soft coalbed methane(CBM)can significantly enhance domestic natural gas supplies,reduce reliance on imported energy,and bolster national energy security.This manuscript provides a comprehensive review of commonly employed coalbed methane extraction technologies.It then delves into several critical issues in the current stage of CBM exploration and development in China,including the compatibility of existing technologies with CBM reservoirs,the characteristics and occurrence states of CBM reservoirs,critical desorption pressure,and gas generation mechanisms.Our research indicates that current CBM exploration and development technologies in China have reached an internationally advanced level,yet the industry is facing unprecedented challenges.Despite progress in low-permeability,high-value coal seams,significant breakthroughs have not been achieved in exploring other types of coal seams.For different coal reservoirs,integrated extraction technologies have been developed,such as surface pre-depressurisation and segmented hydraulic fracturing of coal seam roof strata.Additionally,techniques like large-scale volume fracturing in horizontal wells have been established,significantly enhancing reservoir stimulation effects and coalbed methane recovery rates.However,all of these technologies are fundamentally based on permeation.These technologies lack direct methods aimed at enhancing the diffusion rate of CBM,thereby failing to fully reflect the unique characteristics of CBM.Current CBM exploration and development theories and technologies are not universally applicable to all coal seams.They do not adequately account for the predominantly adsorbed state of CBM,and the complex and variable gas generation mechanisms further constrain CBM development in China.Finally,continuous exploration of new deep CBM exploration technologies is necessary.Integrating more effective reservoir stimulation technologies is essential to enhance technical adaptability concerning CBM reservoir characteristics,gas occurrence states,and gas generation mechanisms,ultimately achieving efficient CBM development.We conclude that while China possesses a substantial foundation of deep fractured CBM resources,industry development is constrained and requires continuous exploration of new CBM exploration and development technologies to utilize these resources effectively.
基金financial support from the National Natural Science Foundation of China(Nos.22278011,22225803,22038001 and 22108007)Beijing Natural Science Foundation(No.Z230023)+1 种基金The Science&Technology Project of Beijing Municipal Education Committee(No.KZ201810005004)Beijing Nova Program(No.Z211100002121094)。
文摘Large-scale deployment of carbon dioxide(CO_(2))removal technology is an essential step to cope with global warming and achieve carbon neutrality.Direct air capture(DAC)has recently received increasing attention given the high flexibility to remove CO_(2)from discrete sources.Porous materials with adjustable pore characteristics are promising sorbents with low or no latent heat of vaporization.This review article has summarized the recent development of porous sorbents for DAC,with a focus of pore engineering strategy and adsorption mechanism.Physisorbents such as zeolites,porous carbons,metal-organic frameworks(MOFs),and amine-modified chemisorbents have been discussed and their challenges in practical application have been analyzed.At last,future directions have been proposed,and it is expected to inspire collaborations from chemistry,environment,material science and engineering communities.
基金supported by the Key Research and Development Program of Shaanxi Province(2023-YBGY361)the National Natural Science Foundation of China(52275374 and 52205414)+1 种基金the Postdoctoral Fellowship Program of CPSF(GZC20232098)as well as the Xiaomi Foundation through Xiaomi Young Scholar Program。
文摘The layer-by-layer deposition strategy of additive manufacturing makes it ideal to fabricate dissimilar alloy components with varying functionality,which has promising application potential in a large number of industrial areas.In this study,two components composed of ERCuAl-A2 aluminum bronze(CuAl9)and Inconel 718 nickel-based superalloy were fabricated with different deposition orders by wire-arc directed energy deposition.Subject to changes in heat input and thermophysical properties of the substrate,the transition region of the deposited Cu-Ni component with the bottom half of CuAl9 and the top half of Inconel 718 is narrow and serrated.This region features a laminated intermetallic compound layer due to the convection and rapid cooling in the molten pool.In contrast,the Ni-Cu component deposited in the opposite order exhibits a 2 mm gradient transition zone.Within this region,a large number of diverse precipitates were found as well as regional variations in grain size due to the multi-layer partial remelting.Both two components show strong bonds and their tensile specimens tested along the vertical direction always fracture at the softer CuAl9 side.Excellent tensile properties along the horizontal direction were obtained for Cu-Ni(Ultimate tensile strength:573 MPa,yield stress:302 MPa,elongation:22%),while those of Ni-Cu are much lower due to the existence of the solidification cracks in the transition zone.The results from this study provide a reference for the additive manufacturing of Cu/Ni dissimilar alloy components,as well as their microstructure and mechanical properties control.
基金supported by Heilongjiang Province Key R&D Program(No.GA22A014)。
文摘For realizing the goals of“carbon peak”and“carbon neutrality”,lithium-ion batteries(LIB)with LiFePO_(4)as the cathode material have been widely applied.However,this has also led to a large number of spent lithium-ion batteries,and the safe disposal of spent lithium-ion batteries is an urgent issue.Currently,the main reason for the capacity decay of LiFePO_(4)materials is the Li deficiency and the formation of the Fe^(3+)phase.In order to address this issue,we performed high-temperature calcination of the discarded lithium iron phosphate cathode material in a carbon dioxide environment to reduce or partially remove the carbon coating on its surface.Subsequently,mechanical grinding was conducted to ensure thorough mixing of the lithium source with the discarded lithium iron phosphate.The reaction between CO_(2)and the carbon coating produced a reducing atmosphere,reducing Fe^(3+)to Fe^(2+)and thereby reducing the content of Fe^(3+).The Fe^(3+)content in the repaired LiFePO_(4)material is reduced.The crystal structure of spent LiFePO_(4)cathode materials was repaired more completely compare with the traditional pretreatment method,and the repaired LiFePO_(4)material shows good electrochemical performance and cycling stability.Under 0.1 C conditions,the initial capacity can reach 149.1 m Ah/g.It can be reintroduced for commercial use.
基金supported by the National Natural Science Foundation of China(Grant No.52404155)State Key Laboratory of Mining Disaster Prevention and Control(Shandong University of Science and Technology)+1 种基金Ministry of Education(Grant No.JMDPC202402)supported by the opening project of State Key Laboratory of Explosion Science and Safety Protection(Beijing Institute of Technology).The opening project number is KFJJ24-20M.
文摘Aiming at mitigating the high risks associated with conventional explosive blasting,this study developed a safe directional fracturing technique,i.e.instantaneous expansion with a single fracture(IESF),using a coal-based solid waste expanding agent.First,the mechanism of directional fracturing blasting by the IESF was analyzed,and the criterion of directional crack initiation was established.On this basis,laboratory experiments and numerical simulations were conducted to systematically evaluate the directional fracturing blasting performance of the IESF.The results indicate that the IESF presents an excellent directional fracturing effect,with average surface undulation differences ranging from 8.1 mm to 22.7 mm on the fracture surfaces.Moreover,during concrete fracturing tests,the stresses and strains in the fracturing direction are measured to be 2.16-3.71 times and 8 times larger than those in the nonfracturing direction,respectively.Finally,the IESF technique was implemented for no-pillar mining with gob-side entry retaining through roof cutting and pressure relief in an underground coal mine.The IESF technique effectively created directional cracks in the roof without causing severe roadway deformation,achieving an average cutting rate and maximum roadway deformation of 94%and 197 mm,respectively.These on-site test results verified its excellent directional rock fracturing performance.The IESF technique,which is safe,efficient,and green,has considerable application prospects in the field of rock mechanics and engineering.
基金supported by the National Natural Science Foundation of China(52005264).
文摘Solution and aging treatment were conducted on the laser directed energy deposition(LDED)-prepared carbon nanotubes(CNTs)-reinforced WE43(CNTs/WE43)layers to optimize their microstructure and surface properties in this study.The microstructure of the WE43 and CNTs/WE43 layers was systematically compared.The dissolution of divorced eutectics at the grain boundaries was retarded by CNTs during solution treatment.The spot segregation composed of Mg_(24)Y_(5),CNTs,and Zr cores in the solution treated CNTs/WE43 layer presented a slight decreasing in Y content.The grain growth of both types of layers underwent three stages:slow,rapid,and steady-state.The significant inhibitory effect of CNTs on the grain growth of the LDED WE43 matrix was more pronounced than the promoting effect of temperature,resulting in a 47%increase at 510℃ and a 35%increase at 540℃ in the grain growth exponent compared to the WE43 layers at 510℃.During the subsequent aging treatment at 225℃,the precipitation sequences from plate-shaped β″to plate-shaped and globular β′ were observed in both types of layers.CNTs can facilitate an increase in the nucleation rate of precipitates,but without accelerating precipitation hardening rate.The long and short diameters of the precipitates in peak-aged state were decreased by 48.5%and 43.1%by addition of CNTs,respectively.The wear resistance of both the WE43 and CNTs/WE43 layers can be significantly enhanced through solution and aging treatment.The enhancement in wear resistance for the CNTs/WE43 layers is considerably greater than that of the WE43 layers.
基金supported by The National Natural Science Foundation of China(Grant Nos.12272411 and 42007259).
文摘Understanding the mesoscopic tensile fracture damage of rock is the basis of evaluating the deterioration process of mechanical properties of heat-damaged rock. For this, tensile tests of rocks under high-temperature treatment were conducted with a ϕ75 mm split Hopkinson tension bar (SHTB) to investigate the mesoscopic fracture and damage properties of rock. An improved scanning electron microscopy (SEM) experimental method was used to analyze the tensile fracture surfaces of rock samples. Qualitative and quantitative analyses were performed to assess evolution of mesoscopic damage of heat-damaged rock under tensile loading. A constitutive model describing the mesoscopic fractal damage under thermo-mechanical coupling was established. The results showed that the high temperatures significantly reduced the tensile strength and fracture surface roughness of the red sandstone. The three-dimensional (3D) reconstruction of the fracture surface of the samples that experienced tensile failure at 900 °C showed a flat surface. The standard deviation of elevation and slope angle of specimen fracture surface first increased and then decreased with increasing temperature. The threshold for brittle fracture of the heat-damaged red sandstone specimens was 600 °C. Beyond this threshold temperature, local ductile fracture occurred, resulting in plastic deformation of the fracture surface during tensile fracturing. With increase of temperature, the internal meso-structure of samples was strengthened slightly at first and then deteriorated gradually, which was consistent with the change of macroscopic mechanical properties of red sandstone. The mesoscopic characteristics, such as the number, mean side length, maximum area, porosity, and fractal dimension of crack, exhibited an initial decline, followed by a gradual increase. The development of microcracks in samples had significant influence on mesoscopic fractal dimension. The mesoscopic fractal characteristics were used to establish a mesoscopic fractal damage constitutive model for red sandstone, and the agreement between the theoretical and experimental results validated the proposed model.
基金National Natural Science Foundation of China(T2188101)。
文摘Among the synthesis techniques for graphene,chemical vapor deposition(CVD)enables the direct growth of graphene films on insulating substrates.Its advantages include uniform coverage,high quality,scalability,and compatibility with industrial processes.Graphene is chemically inert and has a zero-bandgap which poses a problem for its use as a functional layer,and nitrogen doping has become an important way to overcome this.Post-plasma treatment has been explored for the synthesis of nitrogen-doped graphene,but the procedures are intricate and not suitable for large-scale production.We report the direct synthesis of nitrogen-doped graphene on a 4-inch sapphire wafer by ethanol-assisted CVD employing pyridine as the carbon feedstock,where the nitrogen comes from the pyridine and the hydroxyl group in ethanol improves the quality of the graphene produced.Additionally,the types of nitrogen dopant produced and their effects on III-nitride epitaxy were also investigated,resulting in the successful illumination of LED devices.This work presents an effective synthesis strategy for the preparation of nitrogen-doped graphene,and provides a foundation for designing graphene functional layers in optoelectronic devices.
基金supported by the National Natural Science Foundation of China(22472023,22202037)the Jilin Province Science and Technology Development Program(20250102077JC)the Fundamental Research Funds for the Central Universities(2412024QD014,2412023QD019).
文摘Direct ethanol fuel cells(DEFCs)are a promising alternative to conventional energy sources,offering high energy density,environmental sustainability,and operational safety.Compared to methanol fuel cells,DEFCs exhibit lower toxicity and a more mature preparation process.Unlike hydrogen fuel cells,DEFCs provide superior storage and transport feasibility,as well as cost-effectiveness,significantly enhancing their commercial viability.However,the stable C-C bond in ethanol creates a high activation energy barrier,often resulting in incomplete electrooxidation.Current commercial platinum(Pt)-and palladium(Pd)-based catalysts demonstrate low C-C bond cleavage efficiency(<7.5%),severely limiting DEFC energy output and power density.Furthermore,high catalyst costs and insufficient activity impede large-scale commercialization.Recent advances in DEFC anode catalyst design have focused on optimizing material composition and elucidating catalytic mechanisms.This review systematically examines developments in ethanol electrooxidation catalysts over the past five years,highlighting strategies to improve C1 pathway selectivity and C-C bond activation.Key approaches,such as alloying,nanostructure engineering,and interfacial synergy effects,are discussed alongside their mechanistic implications.Finally,we outline current challenges and future prospects for DEFC commercialization.
文摘Professor Paul Crosthwaite,from the School of Literature,Languages,and Cultures at the University of Edinburgh,is a prominent scholar in the interdisciplinary field of literature and economics.He is a co-editor of the Palgrave Studies in Literature,Culture,and Economics series and The Cambridge Companion to Literature and Economics(2022).In recent years,he has significantly influenced the intersection of literature and economics,advocating particularly for a shift towards the Economic Humanities.This interview covers:1.The definition and theoretical origin of the Economic Humanities;2.The internal heterogeneity and critical limitations of the New Economic Criticism,and the theoretical advantages and potential development of the Economic Humanities;3.What research paradigms do Environmental Humanities,Medical Humanities,and Digital Humanities provide for the Economic Humanities;4.How literary researchers can work at the interface of the Economic Humanities research.As a novel interdisciplinary interface between literature and economics,Professor Paul Crosthwaite’s concept of the Economic Humanities not only pioneers methodological tools for interdisciplinary studies of literature and economics but also underscores the interpretative potential and disciplinary benefits of literary viewpoints on economics.This underscores the vital role of literature in human knowledge,meriting attention from the literary research academia.
文摘Plant roots are widely known to provide mechanical reinforcement to soils against shearing and further increase slope stability.However,whether roots provide reinforcement to loess cyclic re-sistance and how various factors affect roots reinforcement during seismic loading have rarely been studied.The objective is to conduct a series of cyclic direct simple shear tests and DEM numerical simulation to investigate the cyclic behaviour of rooted loess.The effects of initial static shear stress and loading frequency on the cyclic resistance of root-soil composites were first investigated.After that,cyclic direct simple shear simulations at constant volume were carried out based on the discrete element method(PFC^(3D))to investigate the effects of root geome-try,mechanical traits and root-soil bond strength on the cyclic strength of rooted loess.It was discovered that the roots could effectively improve the cyclic resistance of loess.The cyclic resistance of the root-soil composite decreases with the increase of the initial shear stress,then increases,and improves with the increase of the frequency.The simulation result show that increases in root elastic modulus and root-soil interfacial bond strength can all enhance the cyclic resistance of root-soil composites,and the maximum cyclic resistance of the root-soil composite was obtained when the initial inclination angle of the root system was 90°.
基金Supported by the Key Laboratory Fund for Equipment Pre-Research(6142207210202)。
文摘Aiming at the problem that infrared small target detection faces low contrast between the background and the target and insufficient noise suppression ability under the complex cloud background,an infrared small target detection method based on the tensor nuclear norm and direction residual weighting was proposed.Based on converting the infrared image into an infrared patch tensor model,from the perspective of the low-rank nature of the background tensor,and taking advantage of the difference in contrast between the background and the target in different directions,we designed a double-neighborhood local contrast based on direction residual weighting method(DNLCDRW)combined with the partial sum of tensor nuclear norm(PSTNN)to achieve effective background suppression and recovery of infrared small targets.Experiments show that the algorithm is effective in suppressing the background and improving the detection ability of the target.
基金supported by Key Natural Science Research Projects of Colleges and Universities in Anhui Province(2022AH051831).
文摘The integration of large-scale new energy and high-capacity DC transmission leads to a reduction in system inertia.Grid-forming renewable energy sources(GF-RES)has a significant improvement effect on system inertia.Commutation failure faults may cause a short-term reactive power surplus at the sending end and trigger transient overvoltage,threatening the safe and stable operation of the power grid.However,there is a lack of research on the calculation method of transient overvoltage caused by commutation failure in high-voltage DC transmission systems with grid-forming renewable energy sources integration.Based on the existing equivalent model of highvoltage DC transmission systems at the sending end,this paper proposes to construct a model of the high-voltage DC transmission system at the sending end with grid-forming renewable energy sources.The paper first clarifies the mechanism of overvoltage generation,then considers the reactive power droop control characteristics of GF-RES,and derives the transient voltage calculation model of theDC transmission system with GF-RES integration.It also proposes a calculation method for transient overvoltage at the sending-end converter bus with GF-RES integration.Based on the PSCAD/EMTDC simulation platform,this paper builds an experimental simulation model.By constructing three different experimental scenarios,the accuracy and effectiveness of the proposed transient overvoltage calculation method are verified,with a calculation error within 5%.At the same time,this paper quantitatively analyzes the impact of grid strength,new energy proportion,and rated transmission power on transient overvoltage from three different perspectives.
