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采用置换还原法在片状铜粉上镀银。对铜粉镀银制备过程及抗氧化性能做了研究。实验结果表明,在铜粉表面首先发生置换反应,生成点缀式银颗粒,之后银颗粒长大,不完全的包覆在铜粉表面,溶液中过量的银离子在还原剂的作用下,表面银层进一步生长,得到完全包覆银的铜粉。通过X-射线衍射分析,片状铜粉镀银层表面未见氧化物,所得粉末表层结构致密。铜粉镀银层具有良好的抗高温氧化性。 相似文献
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由北京化工大学申请的专利(公开号CN103289138A,公开日期2013-09-11)"一种高导电橡胶复合材料及其制备方法",涉及的高导电橡胶复合材料制备方法为:首先通过在氧化石墨烯表面镀银制得高导电填料,然后将其与橡胶水乳液共混使镀银氧化石墨烯以单片层或极少量纳米片层分散在橡胶基体中,再采用原位热压还原方法将氧化石墨烯还原为石墨烯,形成石墨烯片层包裹胶乳粒子的网络结构。这种高导电橡胶复合 相似文献
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镀银层抗变色能力试验 总被引:5,自引:0,他引:5
1前言镀银层在含有盐及硫等粒子的介质中其表面会由原银白色,逐渐转变为黄褐、黑或青蓝等颜色,从而导致电阻率升高。回路电阻大,温升高,影响断路器产品的使用性能。为此开展了对比试验,研究提高镀银层抗变色能力的途径。2试片的制作工艺2.1镀银配方及操作条件硝... 相似文献
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无氰镀银清洁生产技术 总被引:5,自引:1,他引:4
氰化镀银有害环境及健康,已被限制使用并逐渐淘汰,本文在硫代硫酸盐镀银工艺的基础上,通过加入辅助剂及光亮剂,获得了较为理想的无氰镀层,从而开发出一种无氰镀银清洁生产技术。介绍了该无氰镀银的基本原理、工艺规范、前后处理以及镀层的保护方法,并指出了该项技术存在的问题、测定了厚度为10~15μm的该无氰镀银层的结合力、焊接性能、电阻、防腐蚀性能及耐高温性能,并与相同厚度的氰化镀银层进行了比较结果表明,该无氰镀银层质量不亚于氰化镀银层。 相似文献
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在电接触件用T2紫铜表面制备了功能性镀银层。参照相关标准并使用扫描电镜、表面粗糙度测量仪、回路电阻测试仪和盐雾试验机,对镀银层进行了表征。结果表明:镀银层具有银白色金属光泽,与基体的结合力较好;镀银层表面非常平整,表面粗糙度约为0.16μm;镀银使T2紫铜试样的表面粗糙度和接触电阻分别降低了12%和11%;镀银后的T2紫铜试样表现出较好的耐盐雾腐蚀性。 相似文献
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苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况,合成乙苯,苯乙烯所用的催化剂种类,并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。 相似文献
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《国际聚合物材料杂志》2012,61(1-4):113-122
Abstract Kinetics and mechanisms of oxidation of 6 acetals by molecular oxygen and ozone in liquid phase have been studied. Reaction with molecular oxygen (70°C, 15–16 hr) leads to the formation monoethers of the corresponding glycols with 68–90% selectivity. Salts of metals and complexes with crown-ethers have increased the reaction rate significally. Ozone have reacted with acetals with formation similar products. The mechanisms of intermediate stages have been proposed. 相似文献
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The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu3Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu3Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters. 相似文献
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责任是人应主动承担的角色义务和对其因过失所造成后果应承担的责罚.有两层涵义:一是义务;二是后果.责任心是个体自觉做好分内事务和履行道德义务的心理倾向,是个性心理品质成分中自我特征维度上的重要内容.责任心具有两个方面的涵义:一是角色分内职责;二是角色道德义务.责任心是一种通过责任认知、责任个性和责任适应的动态形式表现出来的静态品质,责任心是责任心过程结构与责任心关系结构相互制约、相互影响的统一体. 相似文献
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对用甘油锌作光稳定剂的光稳定作用进行了测试,并与光稳定剂NBC,BZ进行了比较。研究了甘油锌,NBC和BZ与双酚A的复配效果。研究结果表明,甘油锌是一种性能优良的光稳定剂。 相似文献
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Antioxidative activity and phenolic composition of pilot-plant and commercial extracts of sage and rosemary 总被引:5,自引:0,他引:5
Marie-Elisabeth Cuvelier Hubert Richard Claudette Berset 《Journal of the American Oil Chemists' Society》1996,73(5):645-652
Eight sage (Salvia officinalis) and twenty-four rosemary (Rosmarinus officinalis) extracts, originating from pilot-plant or commercial sources, had different antioxidative activities as measured by accelerated
autoxidation of methyl linoleate. Twenty-seven compounds were characterized in the Labiatae family extracts by high-performance
liquid chromatography (HPLC) coupled with mass spectrometry, equipped with an atmospheric pressure chemical ionization interface,
and by HPLC coupled with a photodiode array spectrophotometer. Twenty-two compounds were identified, including phenolic acids,
carnosol derivatives, and flavonoids. The extracts showed great variation in their HPLC profiles, and no correlation was apparent
between their antioxidative efficiency and their composition, in twenty specific phenols. Data indicated that the most effective
compounds were carnosol, rosmarinic acid, and carnosic acid, followed by caffeic acid, rosmanol, rosmadial, genkwanin, and
cirsimaritin. 相似文献