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Effects of pressure oscillations on impinging-jet atomization and spray combustion in liquid rocket engines 被引量:1
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作者 Zhili PENG Bo ZHONG +1 位作者 Xiaodong CHEN Longfei LI 《Chinese Journal of Aeronautics》 2025年第4期25-43,共19页
Combustion dynamics are a critical factor in determining the performance and reliabilityof a chemical propulsion engine.The underlying processes include liquid atomization,evaporation,mixing,and chemical reactions.Thi... Combustion dynamics are a critical factor in determining the performance and reliabilityof a chemical propulsion engine.The underlying processes include liquid atomization,evaporation,mixing,and chemical reactions.This paper presents a high-fidelity numerical study of liquidatomization and spray combustion under high-pressure conditions,emphasizing the effects of pres-sure oscillations on the flow evolution and combustion dynamics.The theoretical framework isbased on the three-dimensional conservation equations for multiphase flows and turbulent combus-tion.The numerical solution is achieved using a coupling method of volume-of-fluid and Lagran-gian particle tracking.The Zhuang-Kadota-Sutton(ZKS)high-pressure evaporation model andthe eddy breakup-Arrhenius combustion model are employed.Simulations are conducted for amodel combustion chamber with impinging-jet injectors using liquid oxygen and kerosene as pro-pellants.Both conditions with and without inlet and outlet pressure oscillations are considered.Thefindings reveal that pressure oscillations amplify flow fluctuations and can be characterized usingkey physical parameters such as droplet evaporation,chemical reaction,and chamber pressure.The spectral analysis uncovers the axial variations of the dominant and secondary frequenciesand their amplitudes in terms of the characteristic physical quantities.This research helps establisha methodology for exploring the coupling effect of liquid atomization and spray combustion.It alsoprovides practical insights into their responses to pressure oscillations during the occurrence ofcombustion instability.This information can be used to enhance the design and operation ofliquid-fueled propulsion engines. 展开更多
关键词 Liquid atomization Spray combustion Pressure oscillations High-pressure evaporation Combustion instability
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Direct numerical simulations of high-pressure impinging-jet atomization:Interfacial evolutions and spray characteristics
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作者 Bo WANG Erjun WU +4 位作者 Anlong YANG Feng ZHANG Baoe YANG Qingquan LIU Xiaodong CHEN 《Chinese Journal of Aeronautics》 2026年第3期158-174,共17页
This study presents a numerical investigation of impinging-jet atomization across various Weber numbers(We) under high backpressure conditions.Using the volume-of-fluid method,adaptive mesh refinement,and the iso Adve... This study presents a numerical investigation of impinging-jet atomization across various Weber numbers(We) under high backpressure conditions.Using the volume-of-fluid method,adaptive mesh refinement,and the iso Advector interface reconstruction technique,atomization characteristics are simulated and analyzed for different values of We.The results indicate that the geometry induces turbulent jets,which drive turbulent atomization through the shear interactions at the gas–liquid interface.The key observed phenomena include the interaction of impact waves with liquid sheet perforation and the breakup of web of ligaments,both of which are prominent under high backpressure conditions.A novel method,based on the threshold velocity of spray droplet groups,is employed to quantitatively measure the spreading angle,showing that the angle increases with We in both front and side views.Additionally,the Sauter mean diameter of droplets follows power-law scaling with exponents of-1/3 in the upstream region and-1/2 in the downstream region,while the droplet size distribution conforms to a log-normal profile.This research provides valuable insights into interface evolution and droplet characteristics during impingingjet atomization under high backpressure,offering essential guidance for optimizing industrial atomization processes. 展开更多
关键词 Direct numerical simulations High-pressure impinging-jet atomization Interfacial evolutions Spray characteristics
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Mechanistic insights and practical applications of impinging-jet dynamics and atomization
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作者 Yongze An Bo Wang +2 位作者 Zhili Peng Xiaodong Chen Vigor Yang 《Acta Mechanica Sinica》 2025年第7期21-37,共17页
This review summarizes recent progress in the study of impinging-jet dynamics and atomization,with a focus on liquid sheet formation,instability mechanisms,and the influence of key parameters such as fluid properties,... This review summarizes recent progress in the study of impinging-jet dynamics and atomization,with a focus on liquid sheet formation,instability mechanisms,and the influence of key parameters such as fluid properties,Weber number,and Reynolds number.Special attention is given to atomization behaviors under high pressure and external perturbations.Representative experimental and numerical approaches are introduced,and critical findings under complex conditions are highlighted.In addition,practical applications of impinging-jet technology in aerospace propulsion,biomedical devices,and energy science are discussed.This review aims to serve as a concise reference for researchers interested in multiphase flow dynamics and engineering applications of impinging jets. 展开更多
关键词 Impinging jets Liquid sheet breakup atomization Interfacial instability Spray dynamics Multiphase flow
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Recent advances in physical understanding and quantitative prediction of impinging-jet dynamics and atomization 被引量:10
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作者 Xiaodong CHEN Vigor YANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2019年第1期45-57,共13页
Impinging-jet injectors are widely used in liquid propulsion applications, since their simple configuration provides reliable and efficient atomization. The flowfield involves a series of complicated spatio-temporal e... Impinging-jet injectors are widely used in liquid propulsion applications, since their simple configuration provides reliable and efficient atomization. The flowfield involves a series of complicated spatio-temporal evolutions. Much effort has been directed toward understanding the underlying physics and developing quantitative predictions of impinging-jet atomization. This paper summarizes the recent advances in this direction, including state-of-the-art theoretical, experimental, and numerical studies, along with representative results. Finally, concluding remarks address remaining challenges and highlight modeling capabilities of high-fidelity simulations. 展开更多
关键词 Computational fluid DYNAMICS FLOW instability FLOW visualization Gas/liquid interfacial DYNAMICS impinging-jet atomization Theoretical models Two-phase FLOW
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Impact of atomization methods on aluminum alloy powder characteristics and 3D printing performance in laser directed energy deposition process 被引量:1
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作者 Gang RUAN Yu-dong LIANG +2 位作者 Gan LI Ying JIN Xing-gang LI 《Transactions of Nonferrous Metals Society of China》 2025年第4期1057-1074,共18页
A comparative study on the performance of gas atomized(GA)and rotating-disk atomized(RDA)aluminum alloy powders produced on industrial scale for laser directed energy deposition(L-DED)process was carried out.The powde... A comparative study on the performance of gas atomized(GA)and rotating-disk atomized(RDA)aluminum alloy powders produced on industrial scale for laser directed energy deposition(L-DED)process was carried out.The powder characteristics,the printing process window,and the quality,microstructure,and mechanical properties of printed parts were taken into account for comparison and discussion.The results demonstrate that the RDA powder is superior to the GA powder in terms of sphericity,surface quality,internal defects,flowability,and apparent density,together with a larger printing process window during the L-DED parts fabrication.Besides,the resultant parts from the RDA powder have higher dimensional accuracy,lower internal defects,more uniform and finer microstructure,and more favorable mechanical properties than those from the GA powder. 展开更多
关键词 metal additive manufacturing rotating disk atomization gas atomization AlSi10Mg powder powder feedstocks
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Numerical Simulation of the Atomization Process for Blast Furnace Slag Granulation
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作者 Li-Li Wang Hong-Xing Qin Nan Dong 《Fluid Dynamics & Materials Processing》 2025年第6期1489-1503,共15页
The so-called close-coupled gas atomization process involves melting a metal and using a high-pressure gas jet positioned close to the melt stream to rapidly break it into fine,spherical powder particles.This techniqu... The so-called close-coupled gas atomization process involves melting a metal and using a high-pressure gas jet positioned close to the melt stream to rapidly break it into fine,spherical powder particles.This technique,adapted for blast furnace slag granulation using a circular seam nozzle,typically aims to produce solid slag particles sized 30–140μm,thereby allowing the utilization of slag as a resource.This study explores the atomization dynamics of liquid blast furnace slag,focusing on the effects of atomization pressure.Primary atomization is simulated using a combination of the Volume of Fluid(VOF)method and the Shear Stress Transport k-ωturbulence model,while secondary atomization is analyzed through the Discrete Phase Model(DPM).The results reveal that primary atomization progresses in three stages:the slag column transforms into an umbrella-shaped liquid film,whose leading edge fragments into particles while forming a cavity-like structure,which is eventually torn into ligaments.This primary deformation is driven by the interplay of airflow velocity in the recirculation zone and the guide tube outlet pressure(Fp).Increasing the atomization pressure amplifies airflow velocity,recirculation zone size,expansion and shock waves,though the guide tube outlet pressure variations remain irregular.Notably,at 4.5 MPa,the primary deformation is most pronounced.Secondary atomization yields finer slag particles as a result of more vigorous primary atomization.For this pressure,the smallest average particle size and the highest yield of particles within the target range(30–140μm)are achieved. 展开更多
关键词 Blast furnace slag granulation close-coupled gas atomization atomization pressure atomization process
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Atomic density disturbance rejection in atomic gyroscopes via faraday polarimetric decoupling
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作者 Zehua Liu Yifan Yan +5 位作者 Haoying Pang Xinhui Liu Jixi Lu Xusheng Lei Zhuo Wang Wei Quan 《Defence Technology(防务技术)》 2026年第1期1-10,共10页
Atomic spin gyroscopes are promising candidates for next-generation inertial navigation due to extremely high theoretical precision,relatively small size among atomic gyroscopes,and promising potential for miniaturiza... Atomic spin gyroscopes are promising candidates for next-generation inertial navigation due to extremely high theoretical precision,relatively small size among atomic gyroscopes,and promising potential for miniaturization.In particular,the spin-exchange relaxation-free(SERF)atomic gyroscope relies on optical pumping to polarize atoms,enabling rotation sensing through the Faraday optical rotation angle(FORA).However,fluctuations in atomic density introduce systematic errors in FORA measurements,limiting long-term stability.We present a data-driven decoupling method that isolates atomic density fluctuations from the FORA signal by modeling spatially resolved light absorption in the vapor cell.The model accounts for the spatial distribution of spin polarization in the pump-light interaction volume,density-dependent relaxation rates,wall-induced relaxation,and polarization diffusion,and is implemented within a finite-element framework.Compared to the conventional Lambert-Beer law,which assumes one-dimensional homogeneity,our approach captures the full threedimensional density and polarization distribution,significantly improving the accuracy of light absorption modeling.The resulting absorption-density maps are used to train a feedforward neural network,yielding a high-precision estimator for atomic density fluctuations.This estimator enables the construction of a decoupling equation that separates the density contribution from the FORA signal.Experimental validation shows that this method improves the bias instability atσ(100 s)of the gyroscope was improved by 73.1%compared to traditional platinum-resistance-based stabilization.The proposed framework is general and can be extended to other optical pumping-based sensors,such as optically pumped magnetometers. 展开更多
关键词 atomic gyroscope SERF gyroscope atomic density Optically pumped sensors
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Synthesis and insecticidal activity evaluation of sulfonamide derivatives oriented by atom replacement strategy
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作者 Hao Qian Xinru Tan +8 位作者 Guixun Wu Lei Wang Ziyu Wang Hongxiang Liu Mei Tian Minjie Zhang Keyin Yu Wenjun Wu Jiwen Zhang 《Advanced Agrochem》 2026年第1期49-57,共9页
The single-atom replacement strategy is a typical approach which just converts elements in lead compounds into their analogues with very small chemical changes.In this research,we implemented this strategy to modify t... The single-atom replacement strategy is a typical approach which just converts elements in lead compounds into their analogues with very small chemical changes.In this research,we implemented this strategy to modify the sulfonamide scaffold identified in our previous work,and resulting in the synthesis of 40 novel sulfonamide derivatives not previously reported in the literature.The insecticidal activities of these compounds against the Mythimna separata and Plutella xylostella were assessed.Our findings indicate that the pyridine sulfonamide structure significantly enhances insecticidal efficacy.Specifically,compound 7c exhibited LC 50 values of 0.157 and 0.256 mg/mL against the M.separata and P.xylostella,which significantly increased 97-and 41-fold compared to celangulin V,respectively.The experimental results revealed that pyridine sulfonamide analogues could serve as potential green insecticides. 展开更多
关键词 SULFONAMIDE SYNTHESIS Insecticidal activity atom replacement Celangulin V
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Atomically Dispersed Pt-Ru Dual-Atom Catalysts for Efficient Low-Temperature CO Oxidation Reaction
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作者 Yanan Qi Hongqiu Chen +12 位作者 Feng Hong Xiangbin Cai Zhehan Ying Jiangyong Diao Zhimin Jia Jiawei Chen Ning Wang Shengling Xiang Xiaowen Chen Guodong Wen Bo Sun Geng Sun Hongyang Liu 《Nano-Micro Letters》 2026年第5期816-830,共15页
Single-atom catalysts(SACs)have demonstrated excellent performance in heterogeneous catalytic reactions owing to their maximized atomic efficiency,distinctive geometric,and electronic configurations.However,the effica... Single-atom catalysts(SACs)have demonstrated excellent performance in heterogeneous catalytic reactions owing to their maximized atomic efficiency,distinctive geometric,and electronic configurations.However,the efficacy of SACs remains limited for certain reactions requiring simultaneous activation of multiple reactants over metallic active sites.Herein,we report an atomically dispersed Pt1Ru1 dual-atom pair site anchored on nanodiamond@graphene(ND@G)for CO oxidation.The Pt1Ru1 dual-atom catalyst shows an exceptional turnover frequency(TOF)of 17.6.10^(-2)s^(-1)at significantly lower temperature(30℃),achieving a tenfold increase in TOF compared to singleatom Pt1/ND@G catalyst(1.5.10^(-2)s^(-1))and surpassing to previously reported Pt-based catalysts under similar conditions.Moreover,the catalyst demonstrates excellent stability,maintaining its activity for 40 h at 80℃without significant deactivation.The superior catalytic performance of Pt-Ru dual-atom catalysts is attributed to the synergistic effect between Pt and Ru atoms with enhanced metallicity for improving simultaneous adsorption and activation of CO and O_(2),and the tuning of conventional competitive reactant adsorption into a non-competitive pathway over dual-atom pair sites.The present work manifests the advantages of dual-atom pair sites in heterogeneous catalysis and paves the way for precise design of catalysts at the atomic scale. 展开更多
关键词 CO oxidation atomically dispersed Dual-atom catalysts Pt-Ru Synergistic effect
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Enantioselective epimerizations of meso-diols via asymmetric hydrogen atom abstraction catalysis
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作者 Xiao Xiao Yu-Xia Jin +3 位作者 Zhi-Qing Wang Li-Hao Liao Peng-Bo Ren Fen-Er Chen 《Green Synthesis and Catalysis》 2026年第1期1-4,共4页
A new type of asymmetric hydrogen atom abstraction catalysts,originated from the cinchona alkaloid family of natural products,has been successfully developed to access enantioselective epimerizations of meso-diols.Aft... A new type of asymmetric hydrogen atom abstraction catalysts,originated from the cinchona alkaloid family of natural products,has been successfully developed to access enantioselective epimerizations of meso-diols.After undergoing single-electron oxidation,the catalyst fulfills desymmetrization of meso-diols by selectively traping a hydrogen atom from a carbon center,which subsequently recaptures a hydrogen atom via abstraction from a thiol.The publication of this work will have a significant influence in the field of asymmetric radical chemistry. 展开更多
关键词 Hydrogen atom abstraction Chiral catalyst Cinchona alkaloid PHOTOCATALYSIS Meso-diols
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Enhanced atomic localization and precision control in a four-level atomic medium via transmission spectrum
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作者 Muhammad Idrees Fatima Ghulam Kakepoto Zareen A Khan 《Communications in Theoretical Physics》 2026年第1期51-60,共10页
In this article,we introduce a new theoretical approach to improve the accuracy of twodimensional(2D)atomic localization within a tripod-type,four-level atomic system by analyzing its transmission spectrum.In this met... In this article,we introduce a new theoretical approach to improve the accuracy of twodimensional(2D)atomic localization within a tripod-type,four-level atomic system by analyzing its transmission spectrum.In this method,the atom interacts with two orthogonal standing-wave fields and a weak probe field.By examining how the weak probe field passes through the system,we can determine the atom position.Our analysis reveals the presence of both double and sharply defined single localized peaks in the transmission spectrum,which correspond to specific positions of the atom.Importantly,we achieve ultra-high-resolution atomic localization with accuracy confined to a region smaller thanλ/32×λ/32.This level of precision is a significant improvement compared to earlier methods,which had lower localization accuracy.The increased precision is due to the complex interaction between the atom and the carefully controlled standing-wave and probe fields,which allows for precise control over the atom's position.The implications of this work are significant,especially for applications like nano-lithography,where precise atomic placement is essential,and for laser cooling technologies,where better atomic localization could lead to more effective cooling processes and improved manipulation of atomic states. 展开更多
关键词 atomic localization transmission spectrum standing-wave fields ultra-high resolution nano-lithography
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Tailoring the Coordination Environment of Single-Atom Catalysts for Enhanced Electrochemical CO_(2)-to-CO Conversion Efficiency
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作者 Xiaoyan Zhang Rui Gao +4 位作者 Zhen Zhang Dezhang Ren Haibo Li Ming Feng Zhongwei Chen 《Carbon Energy》 2026年第3期68-75,共8页
Exploring the influence of the coordination environment of single-atom catalysts(SACs)on the electrochemical CO_(2)reduction reaction is vital for assessing the reaction mechanism and structure-performance relationshi... Exploring the influence of the coordination environment of single-atom catalysts(SACs)on the electrochemical CO_(2)reduction reaction is vital for assessing the reaction mechanism and structure-performance relationship.However,it is challenging to engineer the coordination configuration of isolated active metal atoms precisely.Herein,we strategically manipulate the coordination number of the Co-N_(x) configuration by simply changing the order of adding the metal precursor toward improved CO_(2)electrolysis performance.Compared with the symmetric Co-N_(4)coordination,the asymmetric Co-N_(3)coordination leads to reinforced Co-N interaction and downshifted 3d orbital energy toward the Fermi level of the active Co sites,promoting the activation of CO_(2)molecules and the formation of critical intermediate^(*)COOH.The as-designed Co-N_(3)SAC displays excellent Faradaic efficiency(FE)of 98.4%for CO_(2)-to-CO conversion at a low potential of-0.80 V,together with decent FE over a wide potential range(-0.50 V to-1.10 V)and high durability.This study presents an ideal platform to manipulate the coordination number of atomically dispersed metal catalysts and provides a fundamental understanding of coordination configurationperformance correlation for CO_(2)electroreduction. 展开更多
关键词 carbon dioxide reduction coordination number ELECTROCATALYSIS single atom catalyst
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W/V Dual-Atom Doping MoS_(2)-Mediated Phase Transition for Efficient Polysulfide Adsorption/Conversion Kinetics in Lithium-Sulfur Battery
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作者 Zhe Cui Ping Feng +2 位作者 Gang Zhong Qingdong Ou Mingkai Liu 《Nano-Micro Letters》 2026年第4期700-717,共18页
The dissolvable polysulfides and sluggish Li_2S conversion kinetics are acknowledged as two significant challenges in the application lithium-sulfur(Li-S)batteries.Herein,we introduce a dual-doping strategy to modulat... The dissolvable polysulfides and sluggish Li_2S conversion kinetics are acknowledged as two significant challenges in the application lithium-sulfur(Li-S)batteries.Herein,we introduce a dual-doping strategy to modulate the electronic structure of MoS_(2),thereby obtaining a multifunctional catalyst that serves as an efficient sulfur host.The W/V dual single-atomdoped MoS_(2)grown on carbon nanofibers(CMWVS)demonstrates a strong adsorption ability for lithium polysulfides,suppressing the shuttle effects.Additionally,the doping process also results in the phase transition from 2H-MoS_(2)to 1T-MoS_(2)and generates sufficient edge sulfur atoms,promoting the charge/electron transfer and enriching the reaction sites.All these merits contribute to the superior conversion reaction kinetics,leading to the outstanding Li-S battery performance.When fabricated as cathodes by compositing with sulfur,the CMWVS/S cathode delivers a high capacity of 1481.7 mAh g^(-1)at 0.1 C(1 C=1672 mAh g^(-1))and maintains 816.3 m Ah g^(-1)after 1000 cycles at 1.0 C,indicating outstanding cycling stability.Even under a high sulfur loading of 7.9 mg cm^(-2)and lean electrolyte conditions(E/S ratio of 9.0μL mg^(-1)),the cathode achieves a high areal capacity of 8.2 m Ah cm^(-2),showing great promise for practical Li-S battery applications.This work broadens the scope of doping strategies in transition-metal dichalcogenides by tailoring their electronic structures,providing insightful direction for the rational development of high-efficiency electrocatalysts for advanced Li-S battery applications. 展开更多
关键词 lithium-sulfur batteries ELECTROCATALYST Phase transition Dual single atoms Molybdenum disulfide
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Atomic ensemble-assisted ground-state cooling of a rotating mirror in a triple Laguerre-Gaussian cavity
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作者 Xiaoxuan Li Junfei Chen Qingxia Mu 《Chinese Physics B》 2026年第1期482-490,共9页
We propose a novel cooling protocol within a triple-Laguerre-Gaussian cavity optomechanical system,which is designed to suppress the thermal vibrations of a rotating mirror to reach its quantum ground state.The system... We propose a novel cooling protocol within a triple-Laguerre-Gaussian cavity optomechanical system,which is designed to suppress the thermal vibrations of a rotating mirror to reach its quantum ground state.The system incorporates two auxiliary cavities and an atomic ensemble coupled to a Laguerre-Gaussian rotational cavity.By carefully selecting system parameters,the cooling process of the rotating mirror is significantly enhanced,while the heating process is effectively suppressed,enabling efficient ground-state cooling even in the unresolved sideband regime.Compared to previous works,our scheme reduces the stringent restrictions on auxiliary systems,making it more experimentally feasible under broader parameter conditions.These findings provide a robust approach for achieving ground-state cooling in mechanical resonators. 展开更多
关键词 triple Laguerre-Gaussian cavity rotating mirror ground-state cooling atomic ensemble rotational dynamics
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Single Fe atom anchored by N vacancy of C_(3)N_(4) activates PMS for efficient degradation of refractory organics:The key role of non-radical pathway through 1O_(2) and Fe(IV)=O
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作者 Shenghui Tu Lu Sun +5 位作者 Hongxiang Zhang Jiaqi Xie Leizhen Shen Wenming Liu Guobo Li Honggen Peng 《Journal of Environmental Sciences》 2026年第1期339-348,共10页
Fenton-like technology based on peroxymonosulfate activation has shown great potential in refractory organics degradation.In this work,single Fe atom catalysts were synthesized through facile ball milling and exhibite... Fenton-like technology based on peroxymonosulfate activation has shown great potential in refractory organics degradation.In this work,single Fe atom catalysts were synthesized through facile ball milling and exhibited very high performance in peroxymonosulfate activation.The Fe single-atom filled an N vacancy on the triazine ring edge of C_(3)N_(4),as confirmed through X-ray absorption fine structure,density functional calculation and elec-tron paramagnetic resonance.The SAFe_(0.4)–C_(3)N_(4)/PMS system could completely remove phenol(20 mg/L)within 10 min and its first-order kinetic constant was 12.3 times that of the Fe_(3)O_(4)/PMS system.Under different ini-tial pH levels and in various anionic environments,SAFe_(0.4)–C_(3)N_(4) still demonstrated excellent catalytic activity,achieving a removal rate of over 90%for phenol within 12 min.In addition,SAFe_(0.4)–C_(3)N_(4) exhibited outstanding selectivity in reaction systems with different pollutants,showing excellent degradation effects on electron-rich pollutants only.Hydroxyl radicals(•OH),singlet oxygen(1O_(2))and high-valent iron oxide(Fe(Ⅳ)=O)were de-tected in the SAFe_(0.4)–C_(3)N_(4)/PMS system through free radical capture experiments.Further experiments on the quenching of active species and a methyl phenyl sulfoxide probe confirmed that 1O_(2) and Fe(Ⅳ)=O played dom-inant roles.Additionally,the change in the current response after adding PMS and phenol in succession proved that a direct electron transfer path between organic matter and the catalyst surface was unlikely to exist in the SAFe_(0.4)–C_(3)N_(4)/PMS/Phenol degradation system.This study provides a new demonstration of the catalytic mech-anism of single-atom catalysts. 展开更多
关键词 Refractory organics PMS activation Single atom Singlet oxygen High-valent iron Carbon nitride
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Quantum coherence and thermodynamic performance of an Otto heat engine using a pair of dipole-coupled two-level atoms
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作者 Hao Wang 《Communications in Theoretical Physics》 2026年第1期166-180,共15页
We developed a model of a quantum Otto engine using two coupled two-level atoms.Based on the platform,we show that frequency detuning and the coupling strength induced by dipoledipole interactions can lead to decohere... We developed a model of a quantum Otto engine using two coupled two-level atoms.Based on the platform,we show that frequency detuning and the coupling strength induced by dipoledipole interactions can lead to decoherence by disrupting coherent energy exchange.We focus on fundamental thermodynamic quantities,including heat absorption,release to heat baths,work done and efficiency.It is noteworthy that the interatomic coupling strength and frequency detuning do not merely affect the shape of the work and the efficiency but ultimately govern its quantitative magnitude.In the field of quantum thermodynamics,we have established an upper bound efficiency that is stricter than the Carnot limit.Moreover,our analysis confirms that quantum coherence enables the system to exceed the efficiency threshold of a classical Otto heat engine.The second law of thermodynamics holds all the while.Our results constitute a step forward in the design of conceptually new quantum thermodynamic devices which take advantage of uniquely quantum resources of quantum coherence. 展开更多
关键词 two-level atoms dipole coupled quantum coherence Otto engine local and global efficiency
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Co-optimization of linear gain and dynamic range for atomic superheterodyne receivers based on homodyne readout
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作者 Chuan Qu Dongqin Guo Jian Zhang 《Chinese Physics B》 2026年第1期416-423,共8页
Rydberg-atom-based superheterodyne receivers integrate self-calibration,high sensitivity,a wide operational frequency range,and phase/frequency resolved detection capabilities,demonstrating broad application prospects... Rydberg-atom-based superheterodyne receivers integrate self-calibration,high sensitivity,a wide operational frequency range,and phase/frequency resolved detection capabilities,demonstrating broad application prospects as nextgeneration microwave receivers.Linear gain and linear dynamic range(LDR)are critical metrics for assessing receiver sensitivity and demodulation fidelity,respectively.We numerically solve the four-level master equation and then employ particle swarm optimization(PSO)algorithm to co-optimize linear gain and LDR in atomic superheterodyne receivers based on balanced homodyne detection.Further,we systematically account for dominant dephasing mechanisms in the simulation,encompassing spontaneous decay,transit dephasing,collision dephasing,laser linewidth dephasing,and Doppler averaging.Homodyne readout utilizes both the real and imaginary parts of polarizability for sensing.In the case of the photon shot noise limit,its signal-to-noise ratio(SNR)expression resembles that of direct optical-intensity readout.However,the inherent coherent subtraction operation in homodyne detection significantly suppresses common-mode noise,while appropriately increasing the reference beam power enhances the gain in practical experiments.Indeed,this co-optimization problem,characterized by a high-dimensional variable space,two objectives,and non-convexity,is well-suited for solution by PSO.In addition,probe and coupling detuning contribute equivalently to polarizability and compensate for each other owing to Doppler averaging,thereby reducing the optimization variable space by one.By adopting a product form of linear gain and LDR as the fitness function,the PSO achieves rapid convergence.Here,the effectiveness of the PSO results is verified via the total harmonic distortion(THD).The relative error-based LDR calculation method we proposed efficiently measures receiver response linearity with consuming fewer computational resources.This research is expected to offer valuable insights into enhancing the performance of Rydberg-atom-based superheterodyne receivers. 展开更多
关键词 atomic superheterodyne receivers linear gain linear dynamic range balanced homodyne readout
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Constructing Atomically Dispersed Bimetallic Electrocatalyst by a Topologically Confined Pre-Anchoring Strategy for Enhanced Oxygen Reduction Reaction and Zn-Air Battery
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作者 Yawei Zhang Xia Li Ziqian Xue 《Energy & Environmental Materials》 2026年第1期257-262,共6页
The development of atomically dispersed multi-metallic catalysts is imperative for tailoring catalytic performance and elucidating structure-activity relationships.However,synthesizing such precisely engineered archit... The development of atomically dispersed multi-metallic catalysts is imperative for tailoring catalytic performance and elucidating structure-activity relationships.However,synthesizing such precisely engineered architectures while maintaining atomic dispersion of distinct metal centers remains a formidable challenge due to thermodynamic instability and synthetic complexity.We herein propose a topological confinement pre-anchoring strategy via pre-anchoring spatially resolved Zn/Fe dual-metal sources in a structurally engineered metal-organic framework precursor to synthesize atomically dispersed ZnFe bimetallic single-atom catalysts.Extended X-ray absorption fine structure measurements and X-ray absorption near-edge structure reveal that the atomically dispersed Zn/Fe metal sites and electronic redistribution in ZnFe bimetallic single-atom catalysts.The ultrahigh surface area,hierarchical pore,and synergistic effect between Zn/Fe can greatly favor the exposure of the active site,mass transport,and improvement of intrinsic activity.Consequently,the ZnFe bimetallic single-atom catalyst demonstrates superior oxygen reduction reaction performance,achieving a half-wave potential of 0.86 V and delivering a kinetic current density of 10.1 mA cm^(-2)at 0.85 V versus RHE in 0.1 m KOH electrolyte.These metrics not only surpass those of commercial Pt/C,but also rival the highest-performing catalysts reported to date.The Zn-air battery built with ZnFe bimetallic single-atom catalyst exhibits high power density(278.5 mW cm^(-2))and specific discharging capacities(657 mAh g^(-1)).This work provides a new design pathway for constructing atomically dispersed multi-metal electrocatalysts for high-performance energy-related applications. 展开更多
关键词 bimetallic single atom catalyst metal-organic frameworks oxygen reduction reaction Zn-air battery
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Oxide Semiconductor for Advanced Memory Architectures:Atomic Layer Deposition,Key Requirement and Challenges
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作者 Chi‑Hoon Lee Seong‑Hwan Ryu +3 位作者 Taewon Hwang Sang‑Hyun Kim Yoon‑Seo Kim Jin‑Seong Park 《Nano-Micro Letters》 2026年第6期80-124,共45页
Oxide semiconductors(OSs),introduced by the Hosono group in the early 2000s,have evolved from display backplane materials to promising candidates for advanced memory and logic devices.The exceptionally low leakage cur... Oxide semiconductors(OSs),introduced by the Hosono group in the early 2000s,have evolved from display backplane materials to promising candidates for advanced memory and logic devices.The exceptionally low leakage current of OSs and compatibility with three-dimensional(3D)architectures have recently sparked renewed interest in their use in semiconductor applications.This review begins by exploring the unique material properties of OSs,which fundamentally originate from their distinct electronic band structure.Subsequently,we focus on atomic layer deposition(ALD),a core technique for growing excellent OS films,covering both basic and advanced processes compatible with 3D scaling.The basic surface reaction mechanisms—adsorption and reaction—and their roles in film growth are introduced.Furthermore,material design strategies,such as cation selection,crystallinity control,anion doping,and heterostructure engineering,are discussed.We also highlight challenges in memory applications,including contact resistance,hydrogen instability,and lack of p-type materials,and discuss the feasibility of ALD-grown OSs as potential solutions.Lastly,we provide an outlook on the role of ALD-grown OSs in memory technologies.This review bridges material fundamentals and device-level requirements,offering a comprehensive perspective on the potential of ALD-driven OSs for next-generation semiconductor memory devices. 展开更多
关键词 Oxide semiconductor(OS) atomic layer deposition(ALD) Memory applications
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Single-Atom Ru in CoFe-LDH Drives Efficient Charge Separation on BiVO_(4) for Solar Water Splitting
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作者 Wenhui Deng Gaoshuang He +7 位作者 Haozhi Zhou Wenhao He Lei Gan Chenyu Zhang Keke Wang Xiaoqing Qiu Yang Liu Wenzhang Li 《Nano-Micro Letters》 2026年第6期840-854,共15页
Bismuth vanadate(BiVO_(4))is regarded as a promising photoanode for photoelectrochemical(PEC)water splitting.Despite its advantage in band gap and visible-light response,the BiVO_(4)exhibits an unsatisfactory achievin... Bismuth vanadate(BiVO_(4))is regarded as a promising photoanode for photoelectrochemical(PEC)water splitting.Despite its advantage in band gap and visible-light response,the BiVO_(4)exhibits an unsatisfactory achieving water splitting due to severe charge recombination.Herein,we elucidate an innovative approach involving the incorporation of single Ru atom with a CoFe-LDH cocatalyst(Ru_(0.51)-CoFe-LDH)and integrating it onto the BiVO_(4)semiconductor substrate.The resulting Ru_(0.51)-CoFe-LDH/BiVO_(4)photoanode film demonstrates commendable charge injection efficiency(76%)and charge collection efficiency(100%).Interestingly,the yield of hydrogen and oxygen increases linearly at a stoichiometric ratio of about 2:1,reaching 158.6 and 67.4μmol after140 min of irradiation,respectively.According to experimental characterization and density functional theory calculation,this remarkable performance results from single Ru atoms triggering the electron rearrangement of Ru_(0.51)-CoFe-LDH to engineer active sites and optimize interfacial energetics.Additionally,the negative shift of Ru_(0.51)-CoFe-LDH band edge gives rise to more conspicuous band bending of the n-n junction formed with BiVO_(4),expediting the separation and transfer of photogenerated electron-hole pairs at the interface.This work furnishes a new preparation perspective for PEC water splitting systems to construct single atoms in the semiconductor substrate. 展开更多
关键词 Photo-electrocatalysis Water splitting BiVO_(4)photoanode Ruthenium single atoms Layered double hydroxide
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