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Direct Photolithography of WO_(x) Nanoparticles for High‑Resolution Non‑Emissive Displays 被引量:2
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作者 Chang Gu Guojian Yang +7 位作者 Wenxuan Wang Aiyan Shi Wenjuan Fang Lei Qian Xiaofei Hu Ting Zhang Chaoyu Xiang Yu‑Mo Zhang 《Nano-Micro Letters》 SCIE EI CAS 2025年第3期297-309,共13页
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
关键词 Electrochromic direct photolithography WOx nanoparticles In situ photo-induced ligand exchange High-resolution displays
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Degradation mechanism,direct regeneration and upcycling of ternary cathode material for retired lithium-ion power batteries 被引量:2
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作者 Juan Wang Dongqi Li +6 位作者 Weihao Zeng Xingye Chen Yixin Zhang Shaojie Zhang Zhongpeng Li Changhao Li Shichun Mu 《Journal of Energy Chemistry》 2025年第3期534-554,共21页
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
关键词 Spent NCM materials Retired lithium-ion power battery Degradation mechanism direct regeneration Upcycling strategy
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Porous sorbents for direct capture of carbon dioxide from ambient air 被引量:1
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作者 Yuchen Zhang Lifeng Ding +3 位作者 Zhenghe Xie Xin Zhang Xiaofeng Sui Jian-Rong Li 《Chinese Chemical Letters》 2025年第3期125-133,共9页
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
关键词 direct air capture Carbon neutrality Porous materials PHYSISORPTION CHEMISORPTION
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Heterogeneous interfaces of aluminum bronze/Inconel 718 dissimilar alloys under different wire arc directed energy deposition sequences 被引量:1
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作者 Tianxing Chang Xuewei Fang +4 位作者 You Zhou Hongkai Zhang Naiyuan Xi Shahid Ghafoor Ke Huang 《International Journal of Extreme Manufacturing》 2025年第1期368-381,共14页
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
关键词 wire-arc directed energy deposition dissimilar alloys microstructure aluminum bronze nickel-based super-alloy
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Challenges and development direction of deep fragmented soft coalbed methane in China 被引量:2
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作者 Yiyu Lu Guilin Zhao +7 位作者 Zhaolong Ge Yunzhong Jia Jiren Tang Tianyi Gong Shan Huang Zhongtan Li Wenyu Fu Jianyu Mi 《Earth Energy Science》 2025年第1期38-64,共27页
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
关键词 Deep coalbed methane Exploration and development technology Reservoir characteristics Critical desorption pressure Gas production mechanism Development direction
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Direct regeneration of spent LiFePO_(4)cathode material via a simple solid-phase method 被引量:1
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作者 Hao Sun Xiaoxue Li +5 位作者 Baoyu Wu Kai Zhu Yinyi Gao Tianzeng Bao Hongbin Wu Dianxue Cao 《Chinese Chemical Letters》 2025年第6期745-751,共7页
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
关键词 Spent LiFePO_(4) Carbon dioxide Carbon coating Lithium-iron antiphase defects direct regeneration
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Microstructure evolution of laser directed energy deposition process prepared CNTs/WE43 composites during solution and aging treatment 被引量:1
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作者 Lyuyuan Wang Zhaodian Wang +3 位作者 Lei Zhao Yuan Chen Yangfan Fu Dongsheng Wu 《Journal of Magnesium and Alloys》 2025年第7期3357-3372,共16页
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
关键词 Laser directed energy deposition Cnts-reinforced we43 composite Heat treatment Microstructure evolution
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Non-explosive directional fracturing blasting using coal-based solid waste expanding agent 被引量:1
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作者 Quan Zhang Manchao He +7 位作者 Jiong Wang Shan Guo Chao Wang Chenjie Hong Kai Chen Rongzhou Yang Xuepeng Zhang Jianwei Yang 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第6期3691-3710,共20页
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
关键词 Coal-based solid waste expanding agent directional fracturing blasting Non-explosive Crack initiation Stress-strain-damage evolution
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Mesoscopic fracture damage evolution and fractal damage constitutive model of heat-treated red sandstone under direct tensile impact loadings 被引量:1
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作者 Shi Liu Yu Jia +1 位作者 Yue Zhai Shaoxu Hao 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第1期323-340,共18页
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
关键词 High temperature rock mechanics Dynamic direct tension Red sandstone Mesoscopic fracture mechanism Fractal damage constitutive model
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Ethanol-assisted direct synthesis of wafer-scale nitrogen-doped graphene for III-nitride epitaxial growth
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作者 WEI Wen-ze GAO Xiang +4 位作者 YU Chao-jie SUN Xiao-li WEI Tong-bo JIA Li SUN Jing-yu 《新型炭材料(中英文)》 北大核心 2025年第3期678-687,共10页
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
关键词 III-nitride epitaxy direct synthesis Ethanol-assisted CVD LED devices Nitrogen-doped graphene
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Design and Optimization of Anode Catalysts for Direct Ethanol Fuel Cells:Advances and Challenges in C-C bond Activation and Selective Modulation of the C1 Pathway
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作者 Kai-Chi Qin Meng-Tian Huo +3 位作者 Yu Liang Si-Yuan Zhu Zi-Hao Xing Jin-Fa Chang 《电化学(中英文)》 北大核心 2025年第8期1-22,共22页
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
关键词 direct ethanol fuel cells Ethanol electrooxidation C-C bond cleavage ELECTROCATALYSIS Anode catalyst
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Cyclic behavior of root-loess composites under direct simple shear test conditions and insights from discrete element method modeling
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作者 SUN Yuan LI Hui CHENG Zhifeng 《水利水电技术(中英文)》 北大核心 2025年第S1期665-680,共16页
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
关键词 root-soil composite cyclic direct simple shear tests PFC^(3D)
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New Directions in the Interdisciplinary Studies of Literature and Economics: An Interview with Paul Crosthwaite
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作者 Deng Yingling Paul Crosthwaite 《外国文学研究》 北大核心 2025年第1期1-10,共10页
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
关键词 the Economic Humanities interdisciplinary studies of Literature and Economics new directions Paul Crosthwaite
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Design and Optimization of Terracotta Tube-Based Direct Evaporative Cooling Exchanger: An Analytical Approach to Heat and Mass Transfer
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作者 Windnigda Zoungrana Makinta Boukar +2 位作者 Ousmane Coulibaly Guy Christian Tubreoumya Antoine Bere 《Open Journal of Applied Sciences》 2025年第1期352-373,共22页
This study develops an analytical model to evaluate the cooling performance of a porous terracotta tubular direct evaporative heat and mass exchanger. By combining energy and mass balance equations with heat and mass ... This study develops an analytical model to evaluate the cooling performance of a porous terracotta tubular direct evaporative heat and mass exchanger. By combining energy and mass balance equations with heat and mass transfer coefficients and air psychrometric correlations, the model provides insights into the impact of design and operational parameters on the exchanger cooling performance. Validated against an established numerical model, it accurately simulates cooling behavior with a Root Mean Square Deviation of 0.43 - 1.18˚C under varying inlet air conditions. The results show that tube geometry, including equivalent diameter, flatness ratio, and length significantly influences cooling outcomes. Smaller diameters enhance wet-bulb effectiveness but reduce cooling capacity, while increased flatness and length improve both. For example, extending the flatness ratio of a 15 mm diameter, 0.6 m long tube from 1 (circular) to 4 raises the exchange surface area from 0.028 to 0.037 m2, increasing wet-bulb effectiveness from 60% to 71%. Recommended diameters range from 5 mm for tubes under 0.5 m to 1 cm for tubes 0.5 to 1 m in length. Optimal air velocities depend on tube length: 1 m/s for tubes under 0.8 m, 1.5 m/s for lengths of 0.8 to 1.2 m, and up to 2 m/s for longer tubes. This model offers a practical alternative to complex numerical and CFD methods, with potential applications in cooling tower optimization for thermal and nuclear power plants and geothermal heat exchangers. 展开更多
关键词 Analytical Modeling Porous Terracotta Tube direct Evaporative Cooling Heat and Mass Exchanger Performance Optimization
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Calculation of Commutation Failure Overvoltage in High-Voltage Direct Current Transmission Terminal Systems with Grid-Forming Renewable Energy Sources
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作者 Weibing Xu Bo Yao +5 位作者 Xiangjun Quan Xunyou Zhang Ning Zou Shuo Liu Jia Wang Jiansuo Zhang 《Energy Engineering》 2025年第10期4225-4243,共19页
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
关键词 Grid-forming renewable energy commutation failure transient overvoltage high-voltage direct current sending-end direct current system
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Direction finding for wideband signal and multi-target with interferometer
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作者 PENG Bo SUN Jikang LI Chao 《Journal of Systems Engineering and Electronics》 2025年第5期1132-1139,共8页
According to the measurement principle of the traditional interferometer,a narrowband signal model is established and used,however,for wideband signals or multiple signals,this model is invalid.For the problems of dir... According to the measurement principle of the traditional interferometer,a narrowband signal model is established and used,however,for wideband signals or multiple signals,this model is invalid.For the problems of direction finding with interferometer for wideband signals and multiple signals scene,a frequency domain phase interferometer is proposed and the concrete implementation scheme is given.The proposed method computes the phase difference in frequency domain,and finds multi-target results with judging the spectrum amplitude changing,and uses the frequency phase difference to compute the arrival angle.Theoretical analysis and simulation results show that the proposed method effectively solves the problem of the angle estimation with phase interferometer for wideband signals,and has good performance in multiple signals scene with nonoverlapping spectrum or partially overlapping.In addition,the wider the signal bandwidth,the better direction finding performance of this algorithm. 展开更多
关键词 phase interferometer wideband signal direction finding multi-signal direction finding frequency domain interferometer
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(Light)Interval-Valued Pre-t-Norms and Their Application in Constructing Interval-Valued QL-Directional Monotonic Fuzzy Implications
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作者 Peng YU Siyu DANG Xiaoliang LI 《Journal of Mathematical Research with Applications》 2025年第3期285-303,共19页
Interval-valued pre-aggregation functions are a hot topic in the research of aggregation functions and have received considerable attention in recent years.As a special class of interval-valued pre-aggregation functio... Interval-valued pre-aggregation functions are a hot topic in the research of aggregation functions and have received considerable attention in recent years.As a special class of interval-valued pre-aggregation functions,(light)interval-valued pre-t-norms were initially proposed by Wang and Hu,but their properties were not further discussed by the authors.The main purpose of this paper is to study in depth the properties and generation of(light)intervalvalued pre-t-norms.Firstly,several properties of(light)interval-valued pre-t-norms and their relationship with(light)pre-t-norms are presented.Then,two different generation methods for(light)interval-valued pre-t-norms are introduced.Finally,it demonstrates a specific application of(light)interval-valued pre-t-norms in constructing interval-valued directional monotonic fuzzy implications,namely,using the(light)interval-valued pre-t-norm IT,interval-valued fuzzy negations IN,and(light)interval-valued pre-t-conorm IS to construct interval-valued QL-directional monotonic operations. 展开更多
关键词 (light)interval-valued pre-t-norm aggregation functions interval directional monotonicity interval-valued directional monotonic fuzzy implications
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Evidence of carbide-assisted in situ-directional recrystallization of GH4099 superalloy fabricated by laser powder bed fusion
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作者 Senli Li Jian Liu +4 位作者 Han Zhao Jun Lv Liang Ma Yi Tan Pengting Li 《Journal of Materials Science & Technology》 2025年第12期99-110,共12页
Columnar grains offer considerable advantages in terms of microstructure for resisting high-temperature low-cycle fatigue. In additive manufacturing, the formation of fine columnar grains is common. However, post-heat... Columnar grains offer considerable advantages in terms of microstructure for resisting high-temperature low-cycle fatigue. In additive manufacturing, the formation of fine columnar grains is common. However, post-heat treatment often transforms these grains into equiaxed grains. This study aimed to tailor the grain morphology by controlling the precipitation of carbides. By balancing the restraining effects of carbide pinning and grain growth, we achieved carbide-assisted in situ-directional recrystallization. This process preserved the columnar grains created via laser powder bed fusion, even after high-temperature heat treatment. The approach emphasizes promoting the longitudinal growth of columnar grains while preventing their broadening. Additionally, we characterized the evolution of carbides and γ′ precipitates and examined their role in nucleation and growth during recrystallization. This study supports the viability of carbide-assisted in situ-directional recrystallization in additive manufacturing alloys, introducing an innovative strategy for microstructure customization. The implementation of carbon stabilization (CS) treatment to control the carbide distribution led to a 40 % improvement in the creep life at 900 ℃ and 150 MPa. 展开更多
关键词 Additive manufacturing CARBIDE directional recrystallization SUPERALLOY
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Building the profession of psychological counselling in Ethiopia—achievements,challenges,and future directions
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作者 Adane W.Jarsso Elron S.Fouten Megan M.Campbell 《Journal of Psychology in Africa》 2025年第2期277-285,共9页
Mental healthcare in Ethiopia is underutilized due to a lack of resources and skilled practitioners.Psychological counselling offers unique intervention possibilities because of its focus on a wide range of mental hea... Mental healthcare in Ethiopia is underutilized due to a lack of resources and skilled practitioners.Psychological counselling offers unique intervention possibilities because of its focus on a wide range of mental health and social justice issues.This literature review tracks the historical development of the profession of psychological counselling in Ethiopia to establish what has been achieved to date and the development challenges.Key achievements include recognition of the profession by the Ministry of Education,growing public awareness,and increasing capacity of practitioners skilled in psychological counselling.Challenges include limited contextually relevant training,poor representation of the profession within Ministry of Health policies,poor public and government mental health literacy,and a lack of regulatory frameworks.Postgraduate training would benefit from more culturally,contextually,and linguistically appropriate evidence-based,indigenous psychology practices.The profession would benefit from engagement in government policy development that promotes mental health,and professional regulatory bodies to hold practitioners accountable to professional standards and ethical practice. 展开更多
关键词 psychological counselling Ethiopia ACHIEVEMENTS CHALLENGES future directions
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Infrared small target detection algorithm via partial sum of the tensor nuclear norm and direction residual weighting
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作者 SUN Bin XIA Xing-Ling +1 位作者 FU Rong-Guo SHI Liang 《红外与毫米波学报》 北大核心 2025年第2期277-288,共12页
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
关键词 infrared small target detection infrared patch tensor model partial sum of the tensor nuclear norm direction residual weighting
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