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新型Ag-5%C电接触材料的制备及其电弧磨损特性的研究 总被引:2,自引:1,他引:2
采用将高能球磨、还原剂液相喷雾化学包覆及粉末冶金相结合配以适量碳纳米管做为纤维增强体的工艺 ,制备出新型的Ag 5 %C(质量分数 )电接触材料。该材料具有优异的烧结致密性 ,烧结复压密度可达理论密度的 99.9%,而传统机械混粉工艺及国外发展的烧结挤压工艺同类材料仅能达到 97.0 %~ 98.4%;其硬度达到 64 5MPa ,大大超过同类触头 ;该新型材料由于C在基体中的均匀分布以及高烧结致密性 ,具有很好的导电性能 ,其电导率达到了 3 8 0m·Ω- 1 ·mm- 2 ,远超机械混粉工艺而接近烧结挤压工艺。经由ASTM触头材料试验机进行电磨损分断对比试验 ,发现与常规机械混粉同类触头相比 ,该材料同等条件下电弧磨损量小得多 ,且具有优异的电弧磨损特性 ,其电弧磨损量随分断次数呈指数小于 1的指数函数规律上升 ,即到分断后期其材料损耗量趋于稳定 ,有效抑制了触头分断电涡流磨损现象 ,这种优异的电弧磨损特性对于提高其材料耐电弧磨损性能具有重要意义。该材料有望成为一种可替代烧结挤压和机械混粉同类材料的新型Ag/C触头材料 相似文献
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本次研究区位于甘肃省古浪县裴家营乡半尺沟及五龙沟一带,属于祁连山地中山区,水系极不发育,典型的干旱、半干旱气候。综合使用激电中梯和激电测深两种物探方法进行金属硫化矿的勘探。综合分析双频激电中梯平面、剖面异常特征及电测深断面特征,并结合地表地质特征,最后圈定了1个激电Fs(%)异常和3个局部异常。实践证明:双频激电工作,在此研究区寻找隐伏金属硫化物矿(化)体效果显著。值得今后借鉴使用。 相似文献
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本文对电渣熔铸3Cr2W8V圆钢锭的质量进行研究,结果表明该3Cr2W8V圆钢锭化学成份均匀,金属纯净,组织致密,二次枝晶臂间距小。选用合适的热处理制度可使其抗拉强度和硬度超过锻件水平,冲击韧性也达到锻件水平。 相似文献
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我们国家地质矿产勘查工作具备的专业性较强,只有使用科学有效的技术模式,同时使用多种技术操作去对其进行切实可行的控制才能够让当前矿产勘查的准确性获得有效提高的同时降低矿产勘查和开采工作在资金上的损耗,可是在进行发展中仍然需要面对很多问题。当前状况下,直流电法开始在我国找矿工程中获得了非常普遍的使用。因此,本文针对金属矿产勘查中地质找矿的激电法进行分析和总结。 相似文献
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钛合金表面电弧离子镀TiN/TiAlN多层复合涂层的组织及抗氧化性能研究 总被引:1,自引:0,他引:1
运用电弧离子镀技术,采用独立的钛、铝靶材,在钛合金表面制备了TiN/TiAlN多层复合涂层,利用SEM、EDS对涂层微观组织结构进行了分析,并在800℃条件下测试了涂层抗氧化性能.结果表明:多层复合涂层厚度约为2.5 μm.经镀膜,试样表而粗糙度有升高的趋势,Ra值由初始0.049μm升高到0.541λm.涂层表面以TiAlN TiN相为主,经氧化后,涂层最表层的氮化物已发生分解,并生成了Al,Ti的氧化物,在高温时阻碍了氧向涂层内部扩散,使得涂层内部仍具有TiN和TiAlN的相结构.复合涂层经800℃,19 h空气氧化后,涂层表面仍保持完整,氧化增重率低于无涂层样品.氧化19 h后涂层增重率约为0.2 mg/cm2.h. 相似文献
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为适应新的环保要求,提高深度除尘效果,近年来针对干式静电除尘器进行升级改造,并考虑与湿法脱硫设施协同深度除尘,出现了各类提升、改造技术。对此类技术进行综述和应用分析,为企业改善大气污染排放提供借鉴。 相似文献
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通过对一次三相电源插头内部特殊短路事故的现场复原和相关电器的测试,对插头绝缘材料、结构以及操作过程进行了分析,总结了短路产生的原因,提出了在电工技能训练中避免此类事故再次发生的措施. 相似文献
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采用电弧喷涂技术在Q235钢基体上制备了铝涂层,并用完整涂层和局部破坏涂层两种试样进行室内模拟浸泡腐蚀实验,腐蚀介质为3.5% NaCl水溶液,流速为0.6m·s-1,实验温度为50±1℃.结果表明:涂层局部破坏时的腐蚀速度与涂层完好时相差不大;铝涂层表面的均匀腐蚀并不严重,铝涂层的腐蚀主要是由于闭塞电池和活性-钝性腐蚀微电池的联合作用引起的局部腐蚀,主要类型为点蚀,且涂层层状剥落形成蚀坑;腐蚀介质到达基体时,将发生电偶腐蚀,铝涂层会作为牺牲阳极保护基体免受腐蚀. 相似文献
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A mechanical model was developed for the lifting mechanism of a prototype of the VCF-3t cantilevered vacuum arc furnace,the position and value of maximum stress of the column was obtained through force analysis of the main bearing parts(such as column).Then the actual equipment model was simplified to establish finite element model and the stress cloud chart was compared with actual calculated value in order to test the correctness of the finite element model.On this base,combined with the relationships among actual structure sizes of the furnace,the parametric finite element model was established.If the model meet conditions of intensity and stiffness etc.,the radius and thickness of the column and furnace body was optimized with the optimizer of ANSYS to make the mass of mechanical structure to be the lightest and make full use of the material’s property.At the same time,VB language was used in the call analysis interface in ANSYS to provide an intuitive man-machine system in order to decrease duplication of workload in series design of product.The parameter optimization method used in this paper is an important development of structural optimization design method and has important practical value in the structural design. 相似文献
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The effect of electromagnetic blowing and the slag layer height on the arc efficiency is analytically studied. An arc is blown from under an electrode toward the furnace walls under an electromagnetic force. The arc efficiency of a 100-t high-power electric arc furnace changes from 0.47 to 0.76 when the slag height increases from 0 to 550 mm. 相似文献
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JP Kesslak V So J Choi CW Cotman F Gomez-Pinilla 《Canadian Metallurgical Quarterly》1998,112(4):1012-1019
Brain-derived neurotrophic factor (BDNF) promotes neuron survival, enhances sprouting, protects neurons against insult, and may be involved in several aspects of learning and memory. In this study, rats trained to locate a submerged platform in a water maze had elevated levels of BDNF messenger ribonucleic acid (mRNA) in the hippocampus (p < .05), a structure associated with spatial memory. BDNF mRNA expression increased after 3 and 6 days but not after 1 day of training in the water maze. A yoked control group that swam without the platform present, to control for physical activity, showed a trend for elevated BDNF mRNA at an intermediate level between the learning and sedentary groups. Other cortical and subcortical areas did not show a significant increase in BDNF mRNA after learning or activity (p > .05). These findings suggest that learning can impact BDNF mRNA expression localized to the brain areas involved in the processing of spatial information. Furthermore, behaviors such as physical activity and learning may help maintain and protect neurons at risk in aging and neurodegenerative disease via increased BDNF expression. 相似文献