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41.
This paper shows the wide application range (such as electrical self‐heating and electromagnetic shielding effectiveness) of composites consisting of conductive carbon black/aluminum flakes (CBA) filler and epoxy insulative matrix. The effect of CBA content on the network structure of epoxy matrix was investigated in detail. Static electrical conductivity increases linearly with the increase of filler concentration at the interface in epoxy composites. The large decrease of the conductivity as a function of the temperature is analyzed in terms of the negative temperature coefficient of conductivity (NTCC) effect. The influence of viscosity, surface energy and barrier highest energy on the NTCC behaviour in the composite is also considered. Based on these results, a new interpretation is proposed to explain the NTCC phenomena by computing the swelling force among conductive phases. The correlations of conductivity during the temperature cycling and activation energy were analyzed. The effects of dynamic ageing at various temperatures on the resistivity are reported. Current–voltage–temperature characteristics for epoxy with different contents of CBA were examined in detail. A model based on the law of energy conservation is proposed to calculate the specific heat and amount of heat dissipation. The static charge of the epoxy–CBA composites was estimated. The correlation between electromagnetic wave‐shielding effectiveness (EMS), conductivity and frequency of epoxy composites with different filler contents is also discussed. Furthermore, the effect of annealing on EMS of epoxy composites was examined. © 2002 Society of Chemical Industry 相似文献
42.
通过对双加压法硝酸装置铂网使用情况和铂网脱边事故的统计,分析了氧化炉采用平编三元网存在的问题;论述了经编二元网的特性和优点;计算了铂网的生产强度和接触时间,确定了铂网丝径;总结了硝酸装置使用经编二元网的运行效果和经济效益,结果表明,吨酸氨耗降低了2.48kg,铂耗降低了10mg,经编二元网优于平编三元网。 相似文献
43.
甲醇在聚苯胺修饰铂钼共沉积电极上的催化氧化 总被引:1,自引:0,他引:1
用恒电位法和循环伏安法在铂电极上分别制备了聚苯胺修饰的分散氢钼青铜电极和分散铂电极,以及聚苯胺修饰的不同铂钼比例的铂与氢钼青铜共沉积电极。用循环伏安法研究了制备电极在c(H2SO4)=0.5mol/L水溶液中的电化学行为,以及对c(CH3OH)=0.1 mol/L的催化氧化行为。其中,分散氢钼青铜电极对甲醇无催化氧化的作用,铂与氢钼青铜共沉积电极对甲醇的催化氧化效果优于分散铂电极。铂-氢钼青铜共沉积电极对甲醇氧化的催化能力与共沉积铂钼的比例有关,当制备电极所用的溶液中n(氯铂酸)∶n(钼酸钠)=2∶1时,共沉积电极对甲醇的催化氧化活性最高,此时甲醇在共沉积电极上的氧化峰电流是单纯铂电极的2.632倍。 相似文献
44.
为实现对铂电阻温度传感器的自动测试,设计了基于ZigBee的铂电阻的测试系统.多个高精度微型铂电阻测试节点组网后把测试数据通过汇聚节点传输到计算机.在Windows的开发平台下,利用Delphi7.0+ SQL Server2000技术进行软件研发,实现了铂电阻数据的自动采集、处理、传输、管理、性能评判等功能为一体的自... 相似文献
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48.
Laurie Pesant Joseph Matta Cuong Pham-Huu François Garin Pierre Bernhardt Charlotte Pham Marc-Jacques Ledoux 《Topics in Catalysis》2004,(1):281-286
Platinum catalyst supported on a medium surface area -SiC was successfully used for the catalytic combustion of model carbon particles and compared to a catalyst supported on a low surface area -SiC. The -SiC-based catalyst showed no deactivation as a function of cycling tests while a strong deactivation was observed on the -SiC-based catalyst. This deactivation was attributed to the progressive encapsulation of the platinum particles by a layer of silica which built up during the combustion cycle. These results render possible the use of Pt/-SiC catalyst as a diesel carbon particle catalytic filter with continuous regeneration. 相似文献
49.
Direct methanol alkaline fuel cells with catalysed anion exchange membrane electrodes 总被引:2,自引:0,他引:2
Membrane electrodes prepared by chemical deposition of platinum directly onto the anion exchange membrane electrolyte were tested in direct methanol alkaline fuel cells. Data on the cell voltage against current density performance and anode potentials are reported. The relatively low fuel cell performance was probably due to the low active surface area of Pt deposits on the membrane comparing to other membrane electrode assembly (MEA) fabrication methods. However, the catalysed membrane electrode showed good performance for oxygen reduction. A reduction in cell internal resistance was also obtained for the catalysed membrane electrode. By combining the catalysed membrane electrodes with a catalysed mesh, maximum current density of 98 mA cm–2 and peak power density of 18 mW cm–2 were achieved. 相似文献
50.
Separation of platinum-metal-based homogeneous catalysts was achieved by their conversion to complexes of functionalized phosphines of the general formulae R3-n
P[(CH2)
x
CO2H)]
n
, R = Me, Et, Ph,n = 1, 2, 3,x = 1, 2, and [(HO2CCH2)PCH2]2, followed by extraction of the complexes into aqueous phase. This approach to regeneration of platinum metals from reaction mixtures after carrying out homogeneously catalyzed reactions was demonstrated on 11 examples of various types of reactions with Ru, Rh, Pd, Os, Ir and Pt compounds as catalysts. 相似文献