共查询到18条相似文献,搜索用时 109 毫秒
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高频逆变真空电弧蒸发电源是现代电力电子技术与微电子技术的综合产物,因其具有高效节能、形小体轻、真空电弧稳定等特点,势必发展成为新一代电弧蒸发电源。本文就其主要工作原理、设计计算、实验数据等进行了分析研讨,并举电路实例供参照 相似文献
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高频逆变真空电弧蒸发电源是现代电力电子技术与微电子技术的综合产物,因其具有高效节能、形小体轻、真空电弧稳定等特点,势必发展成为新一代电弧蒸发电源。本文就其主要工作原理、设计计算、实验数据等进行了分析研讨,并举电路实例供参照 相似文献
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针对双弧脉冲MIG焊热源稳定性差的问题,本文对双弧脉冲MIG焊耦合电弧进行瞬态数值模拟,分析了不同脉冲电流参数下耦合电弧形态、温度和压力的分布及变化规律。研究表明:耦合电弧呈驼峰状,脉冲电流发生跳变时,耦合电弧伸展或收缩,并逐渐稳定,峰值电流越小,越快达到稳定;增大脉冲电流,耦合电弧温度和电弧压力随之升高;保持总电流不变,减小主弧电流,增大旁弧电流,主弧温度和电弧压力减小,旁弧温度和电弧压力增大,当旁弧电流足够大时,耦合电弧温度和电弧压力呈双峰分布。数值模拟结果与双弧脉冲MIG焊工艺实验结果吻合良好,模拟结果对调控双弧脉冲MIG焊脉冲电流参数,改善其耦合电弧稳定性及工艺性能具有重要意义。 相似文献
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电弧放电法制备纳米碳管 总被引:33,自引:20,他引:13
纳米碳管的制备方法主要有三种:电弧放电法、激光烧蚀法和有机物催化热解法,首先综述了近年来应用电弧放电方法制备纳米碳管的研究进展,然后概述了中国科学院金属研究所在普通电弧法的基础上发展起来的大量制备单壁纳米碳管的氢等离子电弧方法。 相似文献
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The effect of an external pulse magnetic field with axial and radial components on electric characteristics of the discharge and the configuration of cathode spots of a vacuum arc discharge with ring electrodes is studied experimentally. For arc currents within the range of 0.05–2 kA, shots of the cathode spots at different instants of time are obtained. The dependences of the number of the spots on the discharge current and the mean current per spot are determined. It was found that the expansion rate of the cathode spots area depends significantly on the instant value of the discharge current. It is shown that, when the pulse magnetic field is applied, the discharge voltage increases and the discharge current and number of the cathode spots decreases. It was found that the current interruption is a probability process. The probabilities of the current interruption depending on the maximal value of the external pulse magnetic field induction are determined. 相似文献
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An electrical discharge machine (EDM) can be used to produce Uranium Carbide (UC) microspheres. This material is useful for dispersed nuclear fuel fabrication. To obtain empirical data about the process parameters for UC modeling, 304 stainless steel (304 SS) was used to produce microspheres. Particle size effects were analyzed via three parameters; arc intensity, dielectric medium, and pulse width. Results indicate that the size and yield of the particles are dependent on all three parameters. The yield of larger particles increased with increasing arc current. Particle size distribution decreased with decreasing pulse width. 相似文献
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锁孔TIG焊接技术具有不开坡口、单面焊双面成形的特点,尤其适用于中厚板焊接。首先介绍了锁孔TIG焊的基本原理,然后分析了目前锁孔TIG焊接波形控制技术的研究现状,主要包括恒流锁孔TIG焊、单脉冲锁孔TIG焊和高低频双脉冲锁孔TIG焊。针对现有锁孔TIG焊接技术存在热输入量过大、接头组织晶粒粗大等缺点,重点介绍了一种新型的快频脉冲TIG焊接技术,它通过快频脉冲电流产生的电磁场对电弧进行压缩,控制焊接过程的热输入量,达到提高焊接质量的目的。与传统脉冲电弧相比,快频脉冲电弧的收缩效果更为明显,可细化焊接接头组织,将快频脉冲焊接技术应用于锁孔TIG焊是今后研究的热点和主要发展方向。 相似文献
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Y. Nakada 《Thin solid films》1982,95(2):185-193
During arc discharge between two parallel electrodes, the electrode surface is eroded by the arc. Carbon coating of the electrode surface often results in a decreased erosion. The surface structure of the arc-conditioned carbon-coated copper electrode was metallurgically characterized by the use of (1) scanning electron microscopy and (2) Auger in-depth profiling. Two different types of a.c. conditioning with varying pulse characteristics were studied.It was found that the peak current density, the pulse duration and the total number of pulses were the most important parameters in determining the metallurgical structure of the conditioned electrode surface. The vapor arcs which were produced by pulses with a high current density and short pulse duration were most effective in compacting the carbon coating and promoting good adhesion between the carbon and the copper electrode. The compaction and the adhesion are effected by a high ionic beam pressure on the cathode reaching up to 1000 atm.A lower degree of carbon penetration was effected when surface melting was produced by thermionic arcs which have a lower current density and longer pulse duration. In this case, carbon adhesion is due to the mechanical entrapment of carbon powder in the thin molten copper layer produced on the electrode surface by the arcs. 相似文献
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The cathode attachment of a high-current vacuum arc on the fall of a current pulse was studied. Contacts generating an axial magnetic field were used. The revealed transformation of the attachment shape near zero current was explained quantitatively in a way that was in satisfactory agreement with experimental results. 相似文献
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目的 介绍一种称为Tri-Arc的新型双丝电弧焊接方法。方法 将Tri-Arc双丝电弧焊与应用较广的Tandem双丝电弧焊的系统构成和焊接电流波形进行对比分析。结果 Tri-Arc和Tandem两种双丝电弧焊接方法所使用的双丝焊枪相近,双电源相位同步控制和U/I脉冲控制方式类似。Tri-Arc和Tandem两种双丝电弧焊接方法的差异在于:Tandem双丝电弧焊的2个电弧是相对独立的,而Tri-Arc双丝电弧焊的2个电弧是相互耦合的,因此Tri-Arc双丝电弧焊又具有旁路耦合电弧的某些特点。结论 这种新型的Tri-Arc双丝电弧焊不仅具有与Tandem双丝电弧焊一样的高焊丝熔敷率,而且具有比Tandem双丝电弧焊更低的焊接热输入。 相似文献
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The development of a high-current pulse electric discharge in a rod electrode system with the current amplitude changing from 10 to 100 kA is investigated using a sectional model of a vacuum chamber with the simultaneous recording of the electrical characteristics of the discharge, of the glow of discharge plasma, and of the spots on the electrodes. A phenomenon is revealed of a rapid transition of the discharge from the ignition unit to interrod gaps on reaching an instantaneous value of current from 5 to 9 kA. A correlation is established between the moment of appearance of an abrupt drop of voltage across the vacuum arc and the moment of formation of a new discharge channel in the interrod gap. It is demonstrated that various vacuum arc modes in the interrod gap and the multiplication of discharge channels in all interrod gaps are observed with increasing current. The effect of the rate of current increase on the development of the vacuum arc is investigated. 相似文献