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Platinum-polyaniline-modified carbon fiber electrode for the electrooxidation of methanol 总被引:3,自引:0,他引:3
WUKezhong MENGXu WANGXindong LIJingling 《稀有金属(英文版)》2005,24(1):33-36
Platinum was electrodeposited onto a polyaniline-modified carbon fiber electrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in the level of platinum utilization currently achieved in electrocatalytic systems. This electrode preparation consists of a two-step procedure: fLrst electropolymerization of aniline onto carbon fiber and then electrodeposition of platinum. The catalytic activity of the platinum-polyaniline-modified carbon fiber electrode (Pt/PAni/C) was compared with that of a bare carbon fiber electrode (Pt/C) by the oxidation of methanol. The maximum oxidation current of methanol on Pt/PAni/C is 50.7 mA.cm^-2, which is 6.7 times higher than 7.6 mA.cm^-2 on the Pt/C.Scanning electron microscopy was used to investigate the dispersion of the platinum particles of about 0.4μm. 相似文献
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以碳纤维层压结构中容易产生的分层缺陷为研究对象,采用相控阵超声检测技术进行CIVA仿真和检测试验。通过声场及缺陷的建模和CIVA仿真检测试验,得出了碳纤维层压结构分层缺陷的理想检测参数。设计制作了模拟分层试验件,并进行实际检测试验,结果表明相控阵超声技术可以有效地检测该类缺陷。 相似文献
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介绍了最新的激光视觉传感技术在汽车、造船、管道和铁路车辆等领域的自动化电弧焊接和激光焊接中的应用.先进且可靠的数字激光传感系统保证了电弧或激光热源能准确地对中准焊缝.在焊接过程中能够根据所测量的间隙和错边等数据实时地调整焊接过程参数,并在线检测焊后的焊缝成形和表面缺陷.从而保证焊接质量,并提高生产效率,降低总体焊接生产成本.应用这些适合焊接的智能化激光视觉传感技术.可以有效地提高焊接产品的质量和价格的竞争力. 相似文献
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The reinforcing mechanism of carbon fiber in composite adhesive for bonding carbon/carbon composites
Yunfeng ZhangRuiying Luo Jiangsong ZhangQiao Xiang 《Journal of Materials Processing Technology》2011,211(2):167-173
A carbon fiber reinforced adhesive was developed for bonding carbon/carbon composites. The Weibull distribution method was used to analyze the bonding strength data, and the results showed that when the volume fraction of carbon fiber was 6 vol.%, the Weibull modulus was 42.9393 and the bonding strength of the adhesive was 11.3763 MPa. A model was proposed to explain the reinforcement of carbon fiber, and it was found that the strength of adhesive was a cubic function of the volume fraction of carbon fiber, and the function model was consistent with the Weibull data. We investigated that the carbon fiber could bridge adhesive matrix as a bridging effect for releasing the residual stress and inhibiting the extension of micro-crack. 相似文献
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A high level of cost-intensive manual tasks in the manufacturing process of composite parts impedes a further propagation
of those innovative structures in important German industrial branches like the automotive sector or aviation. Especially
the handling of semi-finished goods in several key process-chains could not be automated efficiently so far due to a great
variety of materials and part contours as well as difficult handling properties of the limp, textile parts. Hence within the
presented work a highly-flexible gripper system based on low-vacuum-suction is introduced, which is the result of a methodical
investigation in the ideal gripping principle. Special actuators and an intelligent control strategy are combined into a selective
gripping technology, which allows an automatic adaption of the pressure based holding force to different contours and materials,
by closing certain apertures of a perforated plate. The experimental validation of a realized robotic end-effector shows that
the challenging requirements of modern composite production could be fulfilled as the structural integrity of the technical
textiles is preserved during the handling processes. 相似文献
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国民经济加速发展需要和综合国力支撑能力提升,使能源工程装备呈现出大型化、系统化和复杂化的显著特点,能源工程装备的工作地点也从陆地向太空、海洋和地下发展.在能源工程装备制造与安装过程中,焊接扮演着非常重要的作用,焊接金属结构件已成为产品制造发展的主要方向,金属结构制造基本实现了以焊代铸,向大型化、成套化、自动化方向的发展已成为时代的主流.新材料(种类和强度级别)不断涌现,因功能需要结构日趋复杂.各种焊接机器人不断涌现,焊接过程及焊接装备智能化特征凸显.智能化设备应有自主的决策能力,能够应付复杂的环境和条件变化.重点介绍无导轨磁吸附球面焊接机器人、复杂空间曲线焊接机器人、海底管道干式高压焊接修复机器人和海洋管道铺设焊接机器人的数字化与智能化. 相似文献
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S. L. Revo I. M. Budzulyak B. I. Rachiy M. M. Kuzishin 《Surface Engineering and Applied Electrochemistry》2013,49(1):68-72
Results are presented of studies of composite materials based on nanoporous carbon for application as an electrode material for supercapacitors with an aqueous KOH electrolyte solution. The optimum concentration ratio of the formula components for the electrode material is found on the basis of the studies of the power-capacitance characteristics of the studied samples of such capacitors. 相似文献
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介绍了微波烧结技术的原理及特点,简要概括了目前制备特种陶瓷的研究现状,并对微波烧结陶瓷材料、硬质合金(WC-Co)、微波烧结金刚石烧结体等问题进行了分析讨论,初步探讨了微波烧结技术在超硬材料制品中广泛应用的可能性。 相似文献
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Matthew J. Van Doren Alexander Slocum 《International Journal of Machine Tools and Manufacture》1995,35(7)
Robotic transfer of silicon wafers in semiconductor fabrication facilities is becoming increasingly attractive. This paper discusses the benefits of a DSP-based computed torque controller over standard PID algorithms for a three degree of freedom, cleanroom material transfer manipulator. Formulation of robot kinematics, dynamic modeling, and numerical simulation assist in the implementation of this nonlinear controller. Simulation and experimental data correlate well and show that a factor of 2–3 times improvement in performance can be obtained. 相似文献
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采用SAXS和HRTEM方法从倒易空间和实空间分别研究了PAN纤维碳化及石墨化过程中长周期结构及其变化。通过HRTEM测试发现碳纤维中存在由石墨微晶的有序堆砌结构,无序堆砌结构及过渡区形成的层状长周期结构,同时碳纤维的SAXS赤道方向散射曲线中出现肩峰,说明这种长周期结构沿纤维径向堆砌。通过SAXS研究发现,在PAN纤维碳化过程中长周期结构从700℃时开始出现且其尺寸随热处理温度的变化呈先增大后减小的趋势,转折温度区域约为1350℃左右。通过一维相关函数分析,计算了长周期结构中石墨微晶有序堆砌结构尺寸(Lo)、无序堆砌结构尺寸(Ld)、过渡区尺寸(Ltr)随热处理温度的变化:1350℃之前,Lo、Ld趋于增大,而Ltr趋于减小;1350℃之后3个参数均呈减小的趋势。 相似文献
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为了提高钢铝异种材料的铆接强度和平整度,提出了神经网络与启发式算法相结合的工艺优化方法.分析了自冲铆接工艺流程,确定了铆接接头质量参数和影响接头质量的工艺参数.设计了铆接实验,采用单隐藏层神经网络对质量参数与工艺参数间的非线性关系进行拟合.经过分析,拟合误差符合正态曲线分布,且误差均值接近于0,误差标准差极小,说明单隐... 相似文献
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Densification mechanism of chemical vapor infiltration technology for carbon/carbon composites 总被引:1,自引:0,他引:1
Carbon/carbon composites were fabricated using pressure-gradient chemical vapor infiltration(CVI) technology with propane (C3H6) as the carbon precursor gas and nitrogen (N2) as the carrier gas. The chemical process of deposition of pyrolytic carbon was deduced by analyzing the component of molecules in gas phase and observing the microstructure of deposition carbon. The results show that the process of deposition starts from the breakdown of C-C single bond of propene (C3H6), and forms two kinds of active groups in the heterogeneous gas phase reaction. Afterwards, these active groups form many stable bigger molecules and deposit on carbon fiber surface. At the same time, hydrogen atoms of the bigger molecules absorbed on carbon fiber surface are eliminated and the solid pyrolytic carbon matrix is formed in the heterogeneous reaction process. 相似文献