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Improving the electrical contact Property of Single-Walled Carbon Nanotube Arrays by Electrodeposition

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Nano-Micro Letters 2013年第4期5卷 242-246页

作者： Min Zhang Advanced Manufacturing Division Graduate School at Shenzhen Tsinghua University

A parallel method for the fabrication of metal contacts on single-walled carbon nanotube(SWNT)arrays was presented and the electrical contact property was evaluated by a SWNT-field effect transistor structure. Copper and gold contacts were fabricated on both semiconducting SWNTs and metallic SWNTs by using a maskless electrodeposition process. The SWNT array remained a p-type semiconductor after the electrodeposition. The contact resistance between SWNT array and microelectrodes was reduced more than 50% by the established copper contacts. The source-drain current of the carbon nanotube field-effect transistor(CNT-FET)structure can be further increased from 7.9 μA to 9.2 μA when the copper contacts were replaced by gold ones,which is probably due to the better contact property to SWNT of gold contacts with fine grain size.

关键词： Carbon nanotube Electrodeposition electrical contact

Evolution of the electrical contact of dynamic pantograph–catenary system

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Journal of Modern Transportation 2016年第2期24卷 132-138页

作者： Guangning Wu Wenfu Wei Guoqiang Gao Jie Wu Yue Zhou School of electrical Engineering Southwest Jiaotong University

A good contact between the pantograph and catenary is critically important for the working reliability of electric trains, while the basic understanding on the electrical contact evolution during the pantograph--catenary system working is still ambiguous so far. In this paper, the evolution of electric contact was studied in respects of the contact resistance, temperature rise, and microstructure variation, based on a home-made pantograph-catenary simulation system. Pure carbon strips and copper alloy contact wires were used, and the experimental electrical current, sliding speed, and normal force were set as 80 A, 30 km/h, and 80 N, respectively. The contact resistance presented a fluctuation without obvious regularity, concentrating in the region of 25 and 50 mf~. Temperature rise of the contact point experienced a fast increase at the first several minutes and finally reached a steady state. The surface damage of carbon trips in microstructure analysis revealed a complicated interaction of the sliding friction, joule heating, and arc erosion.

关键词： Pantograph-catenary system electrical contact Electric trains - contact resistance Temperature rise Microstructure

Preparation of in-situ Cu/NbC nanocomposite and its functionally graded behavior for electrical contact applications

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Transactions of Nonferrous Metals Society of China 2015年第3期25卷 863-872页

作者： S.GHOLAMI SHIRI P.ABACHI K.POURAZARANG M.MOHAMMADI RAHVARD Department of Materials Science and Engineering Sharif University of Technology Damavand Petrochemical Company Phase 2Pars Special Economic Energy Zone School of Materials Science and Engineering and Center of Excellence for High Strength Alloys Technology Iran University of Science and Technology

Cu–15%NbC (volume fraction) powder was synthesized using the starting powders of Cu, Nb and graphite in a high energy vibratory disc mill for 7 h of milling under argon atmosphere. A composite sample and a Cu/NbC functionally graded material (FGM) sample were produced by using the two-step press and sintering at 900 °C for 1 h under vacuum. The microstructure and physical and mechanical properties of the specimens were investigated. The field emission scanning electron microscopy, energy dispersive X-ray and X-ray diffraction analysis confirmed the synthesis of the nanostructure matrix of 18–27 nm with the nanoparticles reinforcement of 42 nm after sintering, verifying the thermal stability of this composite at high temperature. The hardness of Cu–15%NbC was five times greater than that of the pure Cu specimen. The volume reduction of the sample after the wear test decreased in comparison with the pure Cu specimen. The electrical conductivity of the composite specimen decreased to 36.68% IACS. The FGM specimen exhibited high electrical conductivity corresponding to 75.83% IACS with the same hardness and wear properties as those of the composite sample on the composite surface. Thus, Cu/NbC FGM with good mechanical and electrical properties can be a good candidate for electrical contact applications.

关键词： Cu/NbC nanocomposite in-situ composite mechanical alloying electrical contact wear behavior

electrical Conductivity of Spark Plasma Sintered W-Cu and Mo-Cu Composites for electrical contact Applications

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Journal of Minerals and Materials Characterization and Engineering 2021年第1期9卷 48-60页

作者： N. I. Amalu B. A. Okorie J. C. Ugwuoke C. S. Obayi Projects Development Institute (PRODA) Enugu Nigeria Department of Metallurgical and Materials Engineering Enugu State University of Science and Technology Enugu Nigeria Department of Metallurgical & Materials Engineering University of Nigeria Nsukka Nigeria

Tungsten copper and molybdenum copper composites, with weight percent copper in the range of 20% - 40%, have been produced using the spark plasma sintering (SPS) technique. Other specimens having similar compositions were also developed using the conventional techniques of Liquid Phase Sintering (LPS) and Infiltration. electrical conductivity measurements showed that the specimens produced by the SPS process had substantially higher levels of electrical conductivity than those produced by the other methods. Relative density measurements showed that the SPS specimens achieved very high densification, with relative densities in the range of 99.1% - 100%. On the other hand, the specimens produced by LPS and infiltration had relative densities in the range of 88% - 92% and 96% - 98% respectively. The superior conductivity of the SPS specimens has been attributed to the virtually full densification achieved by the process. The effect of porosity on electrical conductivity has been discussed and three standard models were assessed using results from porous sintered skeletons of pure tungsten and pure molybdenum.

关键词： Sintering Infiltration Conductivity Porosity Spark Plasma electrical contact Relative Density

Experiment and finite element method analysis mass erosion and transfer of Ag/La_2NiO_4-based electrical contacts during operation

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Rare Metals 2013年第1期32卷 93-99页

作者： Song Chen Wei-Ming Guan Kun-Hua Zhang Zhi-Long Tan Ming Xie Kunming Institute of Precious Metals State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals

A uniform transient temperature field model of electrical contacts operation was found by analyzing the process of closing arc constriction resistance Joule heat ~ breaking arc. Essential parameters of Ag/La2NiO4 electrical contact material for transient temperature field calculation were obtained through tests of electrical contact experimental instrument under 18 V DC in different cur- rents, other correlation experiments, and calculation anal- ysis. The finite element method was applied to solve the transient temperature field, and the features and distribution of the transient temperature field were obtained. The condition of material erosion and mass transfer can be forecasted by those calculation results. It is beneficial to research about the lifetime of Ag/La2NiO4 electrical material.

关键词： electrical contact Finite element Mass transfer Erosion Temperature field model

Field-effect at electrical contacts to two-dimensional materials

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Nano Research 2021年第12期14卷 4894-4900页

作者： Yao Guo Yan Sun Alvin Tang Ching-Hua Wang Yanqing Zhao Mengmeng Bai Shuting Xu Zheqi Xu Tao Tang Sheng Wang Chenguang Qiu Kang Xu Xubiao Peng Junfeng Han Eric Pop Yang Chai School of Physics Beijing Institute of TechnologyBeijing100081China Department of electrical Engineering and Stanford SystemX Alliance Stanford UniversityStanfordCA94305USA Advanced Manufacturing EDA Co. Ltd.Shanghai201204China Key Laboratory for the Physics and Chemistry of Nanodevices Department of ElectronicsPeking UniversityBeijing100871China Department of Applied Physics The Hong Kong Polytechnic UniversityHong KongChina

The inferior electrical contact to two-dimensional(2D)materials is a critical challenge for their application in post-silicon very large-scale integrated *** contacts were generally related to their resistive effect,quantified as contact *** a systematic investigation,this work demonstrates a capacitive metal-insulator-semiconductor(MIS)field-effect at the electrical contacts to 2D materials:The field-effect depletes or accumulates charge carriers,redistributes the voltage potential,and gives rise to abnormal current saturation and *** one hand,the current saturation hinders the devices’driving ability,which can be eliminated with carefully engineered contact *** the other hand,by introducing the nonlinearity to monolithic analog artificial neural network circuits,the circuits’perception ability can be significantly enhanced,as evidenced using a coronavirus disease 2019(COVID-19)critical illness prediction *** work provides a comprehension of the field-effect at the electrical contacts to 2D materials,which is fundamental to the design,simulation,and fabrication of electronics based on 2D materials.

关键词： field-effect electrical contact two-dimensional materials nonlinearity in-memory-computing

Combined effects of fretting and pollutant particles on the contact resistance of the electrical connectors

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Progress in Natural Science:Materials International 2017年第3期27卷 385-390页

作者： Zhigang Kong Jonathan Swingler Research Laboratory of electrical contacts Beijing University of Post and Telecommunications School of Engineering & Physical Sciences Heriot-Watt University

Usually,when electrical connectors operate in vibration environments,fretting will be produced at the contact *** addition,serious environmental pollution particles will affect contact resistance of the *** fretting will worsen the reliability of connectors with the pollutant *** combined effects of fretting and quartz particles on the contact resistance of the gold plating connectors are studied with a fretting test *** results show that the frequencies have obvious effect on the contact *** higher the frequency,the higher the contact resistance *** quartz particles cause serious wear of gold plating,which make the nickel and copper layer exposed quickly to increase the contact *** in high humidity environments,water supply certain adhesion function and make quartz particles easy to insert or cover the contact surfaces,and even cause opening resistance.

关键词： Gold plating Fretting contact failure electrical contact

Thermo-Mechanical Simulation of Self-Heating of a High-Power Diode Made of Ti_(3)SiC_(2)(MAX) Phase-on-4H-SiC Substrate

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Journal of Thermal Science 2021年第3期30卷 939-949页

作者： ABOU HAMAD Valdemar SOUEIDAN Maher HAMAD Hassan GREMILLARD Laurent FABREGUE Damien ZGHEIB Charbel ZAATAR Youssef LPA Lebanese UniversityFaculty of ScienceJdeidetBP 90656Lebanon MATEIS UMR 5510Universitéde LyonINSA-Lyon20 Avenue Albert EinsteinF-69621 VilleurbanneFrance Lebanese National Council for Scientific Research Lebanese Atomic Energy CommissionRiad El Solh 11072260 BeirutLebanon Lebanese University Faculty of Engineering IIIRafic Hariri University CampusHadathLebanon Department of Physics and Astronomy(DPA) Faculty of Natural Sciences and applied SciencesNotre Dame University-LouaizeLebanon

The fact that traditional semiconductors have almost reached their performance limits in high power applications,is leading to failure in high power *** failure results from self-heating effects,leading to higher temperature and a breakdown of the electrical *** good thermal and mechanical properties of 4 H-SiC and Ti_(3)SiC_(2) and their good performance at high temperatures make them good candidates for high power *** order to improve the performance of electrical contacts,a thermo-mechanical simulation was carried out using the finite element method to study the self-heating effects in a high power PN diode made of a 4 H-SiC substrate with a Ti_(3)SiC_(2) electrical contact and Al_(3)Ti *** three-dimensional model took into account the temperature dependency of several thermal and mechanical properties of the different materials to improve calculation *** simulate the self-heating,the power loss in the diode was calculated from the corresponding direct I-V *** addition,the interfacial thermal resistances(ITR)between the different layers were varied and studied in the thermo-mechanical investigation,in sequence to determine their effects on the heat dissipation and the resulting stresses in the *** results show that for realistic ITR values,the ITR barely affects heat diffusion mechanical stresses of the ***,ITR may cause serious problem to the functionality and the efficiency of some electronic *** the other hand,extremely large ITR leads to a decrease in the thermal stress in the *** control on the ITR may help to improve the performance of high-power devices in the future,in addition to providing more efficient electrical contacts.

关键词： thermo-mechanical simulation self-heating 4H-SiC MAX Phase electrical contact

Enhanced charge collection of AgNWs-based top electrode to realize high-performance,all-solution processed organic solar cells

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Science China Chemistry 2024年第10期67卷 3347-3356页

作者： Juanyong Wan Yang Chen Weijie Chen Jinfeng Xia Guang Zeng Jianlei Cao Chuang Jin Yunxiu Shen Xiaoxiao Wu Haiyang Chen Junyuan Ding Xue-mei Ou Yaowen Li Yongfang Li Laboratory of Advanced Optoelectronic Materials Suzhou Key Laboratory of Novel Semiconductor-Optoelectronics Materials and DevicesCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China Jiangsu Key Laboratory of Advanced Negative Carbon Technologies Soochow UniversitySuzhou 215123China State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials Jiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China Jiangsu Sidike New Materials Science and Technology Co. Ltd.Suqian 215400China

All-solution processed organic solar cells are the ultimate aim of printable photovoltaics,but their electrical losses arising from poor contact of top electrodes greatly limit efficiency *** solve the problem,a solution-processed hybrid top electrode was constructed using silver nanowires(AgNWs)as the skeleton and ZnO nanoparticles(ZnO-NPs)as the *** constructing the skeleton,a spin-rinsing treatment was first used to reduce the amount of the residual insulating polyvinylpyrrolidone wrapped around the AgNWs to promote intimate contact among the AgNWs in the ***,the ZnO-NPs matrix was deposited onto the AgNWs skeleton,bridging the AgNWs skeleton with the underlayer ZnO-NPs electron transporting layer(ETL).The underlayer ZnO-NPs ETL can also induce the growth of the ZnO-NPs matrix to minimize lattice mismatch,which creates additional transport channels from the ETL to the AgNWs skeleton for charge *** a result,the obtained electrode significantly enhances the electrical contact in the device,thus delivering record power conversion efficiencies of 16.04%and 14.54%for rigid and flexible all-solution processed OSCs,respectively.

关键词： solution-processed top electrode organic solar cells AgNWs electrical contact