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INFLUENcES OF DENSITY AND DIMENSION OF cARBON NANOTUBES ON THEIR FIELD EMISSION

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Acta Metallurgica Sinica(English Letters) 2003年第4期16卷 302-308页

作者： Y.B.Zhu W.L.Wang c.g.hu DepartmentofPhysics JiangsuNormalUniversitySuzhou221009ChinaManuscriptreceived25November2002 DepartmentofAppliedPhysics ChongqingUniversityChongqing400044China

The influences of density and dimension of carbon nanotubes on their electron emission from arrays are studied. The tip electric field of nanotubes, electric field enhancement factor, and optimum nanotube density are expressed by analytic equations. The theoretical analyses show that the field enhancement factor is sensitive to nanotube density, and can be sharply improved at a specific and optimum density. Some experiments have demonstrated these. Owning to electrostatic screening effect, the length of carbon nanotubes has little effect on their emission. A uniformly-distributed carbon nanotube array model is set up, and applied to analysis of carbon nanotube arrays. The results obtained here are in good agreement with the experimental data.

关键词： carbon nanotube array field emission optimum density

ELEcTROANALYTIcAL APPLIcATIONS OF cARBOXYL-MODIFIED cARBON NANOTUBE FILM ELEcTRODES

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Acta Metallurgica Sinica(English Letters) 2003年第4期16卷 289-294页

作者： c.g.hu W.L.Wang K.J.Liao W.Zhu DepartmentofAppliedPhysics ChongqingUniversityChongqing400044China KeyLaboftheEducationMinistryforPhotoelectricTechnologyandSystem ChongqingUniversityChongqing400044China Departmentofchemistry ChongqingUniversityChongqing400044ChinaManuscriptreceived25November2002

The electrochemical behavior of a carboxyl-modified carbon nanotube films was investigated to explore its possibility in electroanalytical applicaton. cyclic voltammetry of quinone was conducted in 1mol/L Na2SO4, which showed a stable, quasi-reversible voltammetric response for quinone / hydroquinone, and the anodic and the cathodic peak potentials were 0.657V and -0.029V (vs. ScE) at a scan rate of 0.1V.s-1, respectively. Both anodic and cathodic peak currents depended linearly on the square root of the scan rate over the range of 0.01-0.5V.s-1, which suggested that the process of the electrode reactions was diffusion-controlled. carboxyl-modified carbon nanotube electrodes made it possible to determine low level of dopamine selectively in the presence of a large excess of ascorbic acid in acidic media using derivative voltammetry. The results obtained were discussed in details. This work demonstrates the potential of carboxyl-modified carbon nanotube electrodes for electroanalytical applications.

关键词： carbon nanotube electrochemistry carboxyl modification dopamine

EFFEcT OF ANNEALINg TREATMENT ON THE STRUcTURE OF cdS FILMS

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Acta Metallurgica Sinica(English Letters) 2003年第4期16卷 313-318页

作者： g.B.Liu W.L.Wang c.g.hu K.J.Liao Q.Feng L.H.Feng DepartmentofAppliedPhysics ChongqingUniversityChongqing400044China OptoelectronTechnologyandSystemLaboratoryofEducationMinistry ChongqingUniversityChongqing400044ChinaManuscriptreceived25November2002 DepartmentofMaterialScience SichuanUniversityChengdu610064China

The effect of annealing treatment on the structure of cdS films was investigated. The cadmium sulfide thin films were prepared by chemical bath deposition, and were annealed at nitrogen atmosphere at different temperatures. The films were characterized by SEM and XPS (X-ray photoelectron spectroscopy). X-ray photoelectron spectroscopy was used to examine the chemical states on the cdS films surface. It was found that thermal annealing could produce large grains of cdS thin films, remove the air contamination and reduce the oxygen content on the cdS films surface. Therefore, the cdS films changed more uniform and smoother surface after thermal annealing.

关键词： XPS cdS thin film cBD (chemical bath deposition)

Effect of Nb-V microalloying on the hot deformation behavior of medium Mn steels

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 360-368页

作者： Yumeng Wang Qinyi guo Bin hu Haiwen Luo School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

The influence of Nb-V microalloying on the hot deformation behavior and microstructures of medium Mn steel(MMS)was investigated by uniaxial hot compression *** establishing the constitutive equations for simulating the measured flow curves,we successfully constructed deformation activation energy(Q)maps and processing maps for identifying the region of flow *** concluded the following consequences of Nb-V alloying for MMS.(i)The critical strain increases and the increment diminishes with the increasing deformation temperature,suggesting that Nbc precipitates more efficiently retard dynamic recrystallization(DRX)in MMS compared with solute Nb.(ii)The deformation activation energy of MMS is significantly increased and even higher than that of some reported high Mn steels,suggesting that its ability to retard DRX is greater than that of the high Mn content.(iii)The hot workability of MMS is improved by narrowing the hot processing window for the unstable flow stress,in which fine recrystallized and coarse unrecrystallized grains are present.

关键词： medium manganese steel niobium-vanadium microalloying flow behavior dynamic recrystallization hot workability

co/co_(7)Fe_(3)heterostructures with controllable alloying degree on carbon spheres as bifunctional electrocatalyst forrechargeable zinc-air batteries

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 476-487页

作者： Junkang chen Yongyue Zhuang Yanxin Qiao Yu Zhang Aihua Yuan hu Zhou School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China School of Environmental and chemical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China

Exploring efficient and nonprecious metal electrocatalysts of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is crucial for developing rechargeable zinc-air batteries(ZABs).Herein,an alloying-degree control strategy was employed to fabricate nitrogen-doped carbon sphere(NcS)decorated with dual-phase co/co_(7)Fe_(3)heterojunctions(coFe@NcS).The phase composition of materials has been adjusted by controlling the alloying *** optimal coFe_(0.08)@NcS electrocatalyst displays a half-wave potential of 0.80 V for ORR and an overpotential of 283 mV at 10 mA·cm^(-2)for OER in an alkaline *** intriguing bifunctional electrocatalytic activity and durability is attributed to the hierarchically porous structure and interfacial electron coupling of highly-active co_(7)Fe_(3)alloy and metallic co *** the coFe_(0.08)@NcS material is used as air-cathode catalyst of rechargeable liquid-state zinc-air battery(ZAB),the device shows a high peak power-density(157 mW·cm^(-2))and maintains a stable voltage gap over 150 h,outperforming those of the benchmark(Pt/c+RuO_(2))-based *** particular,the as-fabricated solid-state flexible ZAB delivers a reliable compatibility under different bending *** work provides a promising strategy to develop metal/alloy-based electrocatalysts for the application in renewable energy conversion technologies.

关键词： bifunctional electrocatalysts oxygen reduction reaction oxygen evolution reaction zinc-air battery metal/alloy carbon sphere

Photo‑Energized MoS_(2)/cNT cathode for High‑Performance Li–cO_(2)Batteries in a Wide‑Temperature Range

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Nano-Micro Letters 2025年第1期17卷 160-175页

作者： Tingsong hu Wenyi Lian Kang hu Qiuju Li Xueliang cui Tengyu Yao Laifa Shen Jiangsu Key Laboratory of Materials and Technologies for Energy Storage College of Materials Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016People’s Republic of China

Li–cO_(2) batteries are considered promising energy storage systems in extreme environments such as Mars;however,severe performance degradation will occur at a subzero temperature owning to the sluggish reaction ***,a photo-energized strategy adopting sustainable solar energy in wide working temperature range Li–cO_(2) battery was achieved with a binder-free MoS_(2)/carbon nanotube(cNT)photo-electrode as *** unique layered structure and excellent photoelectric properties of MoS_(2) facilitate the abundant generation and rapid transfer of photo-excited carriers,which accelerate the cO_(2) reduction and Li_(2)cO_(3) decomposition upon *** illuminated battery at room temperature exhibited high discharge voltage of 2.95 V and mitigated charge voltage of 3.27 V,attaining superior energy efficiency of 90.2%and excellent cycling stability of over 120 *** at an extremely low temperature of−30℃,the battery with same electrolyte can still deliver a small polarization of 0.45 V by the photoelectric and photothermal synergistic mechanism of MoS_(2)/cNT *** work demonstrates the promising potential of the photo-energized wide working temperature range Li–cO_(2) battery in addressing the obstacle of charge overpotential and energy efficiency.

关键词： Li-cO_(2)batteries Photo-energized Wide operation-temperature Kinetics MoS_(2)

Electrochemical conversion of methane to bridge the gap in the artificial carbon cycle

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Journal of Energy chemistry 2025年第1期100卷 286-308页

作者： Yuhao Peng Yuefeng Song Ihar Razanau Juanxiu Xiao Wei Xiao Di hu guoxiong Wang college of chemistry and Molecular Sciences Hubei Key Laboratory of Electrochemical Power Sources Wuhan University State Key Laboratory of catalysis Dalian National Laboratory for Clean Energy iChEM (Collaborative Innovation Center of Chemistry for Energy Materials) Dalian Institute of Chemical Physics Chinese Academy of Sciences Laboratory of Physical-chemical Technologies SSPA Scientific and Practical Materials Research Centre of NAS of Belarus State Key Laboratory of Marine Resources Utilization in South china Sea Collaborative Innovation Center of Marine Science and Technology School of Marine Science and Engineering Hainan University Department of chemical and Environmental Engineering University of Nottingham Ningbo China

Methane, an abundant one-carbon（c1） resource, is extensively used in the industrial production of vital fuels and value-added chemicals. However, current industrial methane conversion technologies are energy-and carbon-intensive, mainly due to the high activation energy required to break the inert c–H bond, low selectivity, and problematic side reactions, including cO2emissions and coke deposition. Electrochemical conversion of methane（EcM） using intermittent renewable energy offers an attractive solution, due to its modular reactor design and operational flexibility across a broad spectrum of temperatures and pressures. This review emphasizes conversion pathways of methane in various reaction systems, highlighting the significance and advantages of EcM in facilitating a sustainable artificial carbon cycle. This work provides a comprehensive overview of conventional methane activation mechanisms and delineates the complete pathways of methane conversion in electrolysis contexts. Based on surface/interface chemistry, this work systematically analyzes proposed reaction pathways and corresponding strategies to enhance EcM efficiency towards various target products, including syngas, hydrocarbons, oxygenates, and advanced carbon materials. The discussion also encompasses opportunities and challenges for the EcM process, including insights into EcM pathways, rational electrocatalyst design, establishment of benchmarking protocols, electrolyte engineering, enhancement of cH4conversion rates, and minimization of cO2emission.

关键词： Methane Electrochemical conversion Reaction mechanism catalyst design Electrode Electrocatalysis

A Novel Model for Describing Rail Weld Irregularities and Predicting Wheel-Rail Forces Using a Machine Learning Approach

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computer Modeling in Engineering & Sciences 2025年第1期142卷 555-577页

作者： Linlin Sun Zihui Wang Shukun cui Ziquan Yan Weiping hu Qingchun Meng State Key Laboratory of High-Speed Railway Track System China Academy of Railway Sciences Corporation LimitedBeijing100081China Railway Engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing100081China School of Aeronautic Science and Engineering Beihang UniversityBeijing100191China

Rail weld irregularities are one of the primary excitation sources for vehicle-track interaction dynamics in modern high-speed *** can cause significant wheel-rail dynamic interactions,leading to wheel-rail noise,component damage,and *** researchers have employed the vehicle-track interaction dynamic model to study the dynamic interactions between wheel and rail induced by rail weld geometry ***,the cosine wave model used to simulate rail weld irregularities mainly focuses on the maximum value and neglects the geometric *** this study,novel theoretical models were developed for three categories of rail weld irregularities,based on measurements of the high-speed railway from Beijing to *** vertical dynamic forces in the time and frequency domains were compared under different running *** forces generated by the rail weld irregularities that were measured and modeled,respectively,were compared to validate the accuracy of the proposed ***,based on the numerical study,the impact force due to rail weld irrregularity is modeled using an Artificial Neural Network(ANN),and the optimum combination of parameters for this model is *** results showed that the proposed model provided a more accurate wheel/rail dynamic evaluation caused by rail weld irregularities than that established in the *** ANN model used in this paper can effectively predict the impact force due to rail weld irrregularity while reducing the computation time.

关键词： Rail weld irregularity high-speed railway vehicle-track coupled dynamics wheel/rail dynamic vertical force artificial neural networks

Spin-glass behavior in the competing cocrgaO_(4)cubic spinel system

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Nano Research 2025年第1期18卷 501-507页

作者： Jiyu hu Jiangli Ni Zhenfa Zi chaocheng Liu School of Physics and Materials Engineering Hefei Normal UniversityHefei 230009China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230026China

Spin glasses(Sgs),generally defined as disordered systems with randomized competing interactions,are widely investigated complex *** the ground states of spin glasses is crucial for understanding the nature of disordered magnets and many other physical manifestations,while also helping to solve some hard combinatorial optimization problems across multiple ***,the intrinsic cause of Sg has always been elusive,especially in spinel oxide ***,we report the Sg behavior observed in the cubic spinel oxides cocrgaO_(4),and provide a comprehensive understanding of its intrinsic *** results indicate a frustrated state under multi-magnetic competition,and the features of Sg are confirmed by susceptibility *** fitting parameters ofτ0,T0,and zv of isothermal remanent magnetization further reveal the relaxation behavior and strong spin ***,the varying exchange coupling under different temperatures and magnetic fields is unveiled,which should be responsible for the disordered *** studies unravel the underlying mechanism responsible for doping-induced magnetic frustration and introduce cocrgaO_(4)as a potential platform for investigating spin glass behavior,thereby advancing fundamental research on frustrated magnetism within the spinel system.

关键词： spin glass(Sg) magnetic frustration magnetic competition spinel ferrites