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提出了一种基于ARM处理器的电导率测量系统的设计方案,ARM处理器S3C2410对采集的电流信号和温度信号进行处理,经温度补偿后得到固定温度下的电导率后送入液晶显示,给出了系统测量的修正办法.测试结果表明:该系统功耗低、性能稳定、扩展性强. 相似文献
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Mohammad Razaul Karim Hideaki Shinoda Mina Nakai Kazuto Hatakeyama Hidenobu Kamihata Takeshi Matsui Takaaki Taniguchi Michio Koinuma Keita Kuroiwa Mohamedally Kurmoo Yasumichi Matsumoto Shinya Hayami 《Advanced functional materials》2013,23(3):323-332
The rare coexistence of ferromagnetism and electrical conductivity is observed in the reduced graphene oxide–metal oxide hybrids, rGO‐Co, rGO‐Ni, and rGO‐Fe, using chemical reduction with hydrazine or ultraviolet photoirradiation of the graphene oxide–metal complexes, GO‐Co, GO‐Ni, and GO‐Fe. The starting and final materials are characterized by X‐ray photoelectron spectroscopy, transmission electron microscopy (TEM), elemental analysis, Mössbauer spectroscopy, and Raman spectroscopy. In contrast to graphene, where the electrical conductivity and magnetic properties are controlled by carrier (electron or hole) doping, those of graphene oxide can be controlled by complexation with Co2+, Ni2+, and Fe3+ cations through the strong electrostatic affinity of negatively charged graphene oxide towards metal cations. The presence of ferromagnetism and electrical conductivity in these hybrids can promote significant applications including magnetic switching and data storage. 相似文献
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Mu Cao Ding‐Bang Xiong Li Yang Shuaishuai Li Yiqun Xie Qiang Guo Zhiqiang Li Horst Adams Jiajun Gu Tongxiang Fan Xiaohui Zhang Di Zhang 《Advanced functional materials》2019,29(17)
Highly efficient conductors are strongly desired because they can lead to higher working performance and less energy consumption in their wide range applications. However, the improvements on the electrical conductivities of conventional conductors are limited, such as purification and growing single crystal of metals. Here, by embedding graphene in metals (Cu, Al, and Ag), the trade‐off between carrier mobility and carrier density is surmount in graphene, and realize high electron mobility and high electron density simultaneously through elaborate interface design and morphology control. As a result, a maximum electrical conductivity three orders of magnitude higher than the highest on record (more than 3,000 times higher than that of Cu) is obtained in such embedded graphene. As a result, using the graphene as reinforcement, an electrical conductivity as high as ≈117% of the International Annealed Copper Standard and significantly higher than that of Ag is achieved in bulk graphene/Cu composites with an extremely low graphene volume fraction of only 0.008%. The results are of significance when enhancing efficiency and saving energy in electrical and electronic applications of metals, and also of interest for fundamental researches on electron behaviors in graphene. 相似文献
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Electrical Conductivity Gradient Based on Heterofibrous Scaffolds for Stable Lithium‐Metal Batteries
Sang‐Ho Hong Dae‐Han Jung Jung‐Hwan Kim Yong‐Hyeok Lee Sung‐Ju Cho Sang Hoon Joo Hyun‐Wook Lee Ki‐Suk Lee Sang‐Young Lee 《Advanced functional materials》2020,30(14)
The inability to guide the nucleation locations of electrochemically deposited Li has long been considered the main factor limiting the utilization of high‐energy‐density Li‐metal batteries. In this study, an electrical conductivity gradient interfacial host comprising 1D high conductivity copper nanowires and nanocellulose insulating layers is used in stable Li‐metal anodes. The conductivity gradient system guides the nucleation sites of Li‐metal to be directed during electrochemical plating. Additionally, the controlled parameter of the intermediate layer affects the highly stable Li‐metal plating. The electrochemical behavior is confirmed through experiments associated with the COMSOL Multiphysics simulation data. The distributed Li‐ion reaction flux resulting from the controlled electrical conductivity enables stable cycling for more than 250 cycles at 1 mA cm?2. The gradient system effectively suppresses dendrite growth even at a high current density of 5 mA cm?2 and ensures Li plating and stripping with ultra‐long‐term stability. To demonstrate the high‐energy‐density full‐cell application of the developed anode, it is paired with the LiNi0.8Co0.1Mn0.1O2 cathode. The cells demonstrate a high capacity retention of 90% with an extremely high Coulombic efficiency of 99.8% over 100 cycles. These results shed light on the formidable challenges involved in exploiting the engineering aspects of high‐energy‐density Li‐metal batteries. 相似文献
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研究了不同含氮量的类金刚石薄膜(DLC:N)的导电性能,发现随着氮含量的增加,薄膜的电导率增加较缓,当氮含量达到一定值(12.8at%)后,薄膜电导率反而随氮含量的继续增加而下降。将薄膜在300℃下退火30min,结果表明低参氮的薄膜退火后导电性能有了较大的提高,而高掺氮的薄膜退火后电导率有所下降。Raman和XPS光谱研究表明,当薄膜中的氮含量达到一定值后,在薄膜中会出现非导电(a-CNx)的成分,因此高掺杂的类金刚石薄膜的电导率下降。FTIR光谱表明,充当施主杂质中心的氮原子在薄膜退火过程中存在被“激活”的现象,从而提高了电导率。因此氮对高掺杂和低掺杂薄膜导电性能的影响是不同的。 相似文献
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主要讨论NTC多晶氧化物半导体中晶界对电导的影响。研究表明,NTC多晶氧化物半导体的电导是由晶粒中载流子的热激发并穿过晶界势垒形成的,电导同时受晶粒和晶界的控制;材料的电阻–温度特性不是严格的指数曲线;材料常数与温度有关。因此,研究晶界的行为,对制备高性能NTC材料具有重要意义。 相似文献
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Strongly Anisotropic Thermal Conductivity of Free‐Standing Reduced Graphene Oxide Films Annealed at High Temperature 下载免费PDF全文
Jackie D. Renteria Sylvester Ramirez Hoda Malekpour Beatriz Alonso Alba Centeno Amaia Zurutuza Alexandr I. Cocemasov Denis L. Nika Alexander A. Balandin 《Advanced functional materials》2015,25(29):4664-4672
Thermal conductivity of free‐standing reduced graphene oxide films subjected to a high‐temperature treatment of up to 1000 °C is investigated. It is found that the high‐temperature annealing dramatically increases the in‐plane thermal conductivity, K, of the films from ≈3 to ≈61 W m?1 K?1 at room temperature. The cross‐plane thermal conductivity, K⊥, reveals an interesting opposite trend of decreasing to a very small value of ≈0.09 W m?1 K?1 in the reduced graphene oxide films annealed at 1000 °C. The obtained films demonstrate an exceptionally strong anisotropy of the thermal conductivity, K/K⊥ ≈ 675, which is substantially larger even than in the high‐quality graphite. The electrical resistivity of the annealed films reduces to 1–19 Ω □?1. The observed modifications of the in‐plane and cross‐plane thermal conductivity components resulting in an unusual K/K⊥ anisotropy are explained theoretically. The theoretical analysis suggests that K can reach as high as ≈500 W m?1 K?1 with the increase in the sp2 domain size and further reduction of the oxygen content. The strongly anisotropic heat conduction properties of these films can be useful for applications in thermal management. 相似文献
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Qianwen Li Hang Wang Xinfeng Tang Min Zhou Huaping Zhao Yang Xu Wei Xiao Yong Lei 《Advanced functional materials》2021,31(24):2101081
Sodium-ion battery (SIB) is significant for grid-scale energy storage. However, a large radius of Na ions raises the difficulties of ion intercalation, hindering the electrochemical performance during fast charge/discharge. Conventional strategies to promote rate performance focus on the optimization of ion diffusion. Improving interface capacitive-like storage by tuning the electrical conductivity of electrodes is also expected to combine the features of the high energy density of batteries and the high power density of capacitors. Inspired by this concept, an oxide-metal sandwich 3D-ordered macroporous architecture (3DOM) stands out as a superior anode candidate for high-rate SIBs. Taking Ni-TiO2 sandwich 3DOM as a proof-of-concept, anatase TiO2 delivers a reversible capacity of 233.3 mAh g−1 in half-cells and 210.1 mAh g−1 in full-cells after 100 cycles at 50 mA g−1. At the high charge/discharge rate of 5000 mA g−1, 104.4 mAh g−1 in half-cells and 68 mAh g−1 in full-cells can also be obtained with satisfying stability. In-depth analysis of electrochemical kinetics evidence that the dominated interface capacitive-like storage enables ultrafast uptaking and releasing of Na-ions. This understanding between electrical conductivity and rate performance of SIBs is expected to guild future design to realize effective energy storage. 相似文献
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采用波长为248 nm的准分子激光辐照聚偏氟乙烯(PVDF)薄片,可使其表面电导率从10-13 (Ω·cm)-1上升到10-4 (Ω·cm)-1,实现了由绝缘到导电的转变。通过调整激光能量密度、环境气氛、脉冲频率和辐照脉冲数等参数,确定出激光辐照诱导PVDF导电性的最佳工艺条件。通过对被辐照样品进行X射线衍射谱(XRD)、拉曼散射光谱和显微分析可知:紫外激光打断了PVDF的C-F键,并在样品表面生成了石墨导电层是PVDF由绝缘态向导电态转变的原因。 相似文献
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利用SABER^TM软件对聚合物激光应永久电导进行了计算机模拟。首次分析了聚 物的激光感应金属-绝缘体相变阈值附近的介电系数的增大。根据模拟初步估算,介是系数约有6倍增加,此外,对相变条件进行了阐述。 相似文献
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Fei Zhang Yiyu Feng Mengmeng Qin Long Gao Zeyu Li Fulai Zhao Zhixing Zhang Feng Lv Wei Feng 《Advanced functional materials》2019,29(25)
Stress controllability in thermal and electrical conductivity is important for flexible piezoresistive devices. Due to the strength‐elasticity trade‐off, comprehensive investigation of stress‐controllable conduction in elastic high‐modulus polymers is challenging. Here presented is a 3D elastic graphene‐crosslinked carbon nanotube sponge/polyimide (Gw‐CNT/PI) nanocomposite. Graphene welding at the junction enables both phonon and electron transfer as well as avoids interfacial slippage during cyclic compression. The uniform Gw‐CNT/PI comprising a high‐modulus PI deposited on a porous templated network combines stress‐controllable thermal/electrical conductivity and cyclic elastic deformation. The uniform composites show different variation trends controlled by the porosity due to different phonon and electron conduction mechanisms. A relatively high k (3.24 W m?1 K?1, 1620% higher than PI) and suitable compressibility (16.5% under 1 MPa compression) enables the application of the composite in flexible elastic thermal interface conductors, which is further analyzed by finite element simulations. The interconnected network favors a high stress‐sensitive electrical conductivity (sensitivity, 973% at 9.6% strain). Thus, the Gw‐CNT/PI composite can be an important candidate material for piezoresistive sensors upon porosity optimization based on stress‐controllable thermal or electrical conductivity. The results provide insights toward controlling the stress‐induced thermal/electrical conductivities of 3D interconnected templated composite networks for piezoresistive conductors or sensors. 相似文献
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Daniil Bash Yongqiang Cai Vijila Chellappan Swee Liang Wong Xu Yang Pawan Kumar Jin Da Tan Anas Abutaha Jayce JW Cheng Yee-Fun Lim Siyu Isaac Parker Tian Zekun Ren Flore Mekki-Berrada Wai Kuan Wong Jiaxun Xie Jatin Kumar Saif A. Khan Qianxiao Li Tonio Buonassisi Kedar Hippalgaonkar 《Advanced functional materials》2021,31(36):2102606
Combining high-throughput experiments with machine learning accelerates materials and process optimization toward user-specified target properties. In this study, a rapid machine learning-driven automated flow mixing setup with a high-throughput drop-casting system is introduced for thin film preparation, followed by fast characterization of proxy optical and target electrical properties that completes one cycle of learning with 160 unique samples in a single day, a > 10 × improvement relative to quantified, manual-controlled baseline. Regio-regular poly-3-hexylthiophene is combined with various types of carbon nanotubes, to identify the optimum composition and synthesis conditions to realize electrical conductivities as high as state-of-the-art 1000 S cm−1. The results are subsequently verified and explained using offline high-fidelity experiments. Graph-based model selection strategies with classical regression that optimize among multi-fidelity noisy input-output measurements are introduced. These strategies present a robust machine-learning driven high-throughput experimental scheme that can be effectively applied to understand, optimize, and design new materials and composites. 相似文献
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电缆用高分子材料电气性能的探讨 总被引:1,自引:0,他引:1
周俊民 《光纤与电缆及其应用技术》2010,(3):5-7
高分子材料的电气性能是由高分子材料内部结构决定的,用于不同的电压等级和使用环境的电缆在考核电缆用高分子材料的电气性能时,应有针对性地进行参数指标考核。 相似文献
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电反馈对FM光发射机信噪比性能的改善 总被引:1,自引:0,他引:1
本文研究了电反馈半导体激光器作为FM光发射机的信噪比性能。分析表明:电反馈可以改善FM光发射机的信噪比性能。这种改善在适当的反馈条件下可达近30dB。反馈环路存在着最佳增益使信噪比达到最大。 相似文献