排序方式: 共有76条查询结果,搜索用时 62 毫秒
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A new kind of simple and flexible CO2 welding system was developed to carry out waveform control. The system consisted of IGBT inverter, PWM circuit and microprocessor unit ( MPU) , in which the output current of constant current (CC) power supply could be changed according to transient physical state, and the variable down slope rate control could be used to ensure a stable welding process. The welding experiment results proved the effectiveness of this control approach. 相似文献
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分析了隔直电容在全桥式逆变电路中抗变压器偏磁的原理,以及隔直电容对逆变孤焊电源的输出功率的影响,并在电容参数值不同的情况下用PSPISE软件仿真进行验证分析,从分析结果中变压器一次侧电压波形的对称性可以看出,隔直电容对孤焊逆变电源变压器偏磁有一定的抑制作用,同时对电源输出功率有较大影响。 相似文献
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Creep property of solder alloys is one of the important factors to affect the reliabdity of soldered joints in SMT (surface mount technology). Particle-enhancement is a way to improve the properties of solder alloys and has caused much more attention than before. Temperatures applied to soldered joints are one of the primary factors of affecting creep properties of particle enhancement composite soldered joints. In this paper single shear lap creep specimens with a 1 mm^2 cross-sectional area were fabricated using Cu particle enhancement 63Sn37 Pb based composite soldered joints and 63Sn37 Pb eutectic soldered joints to examine the influence of temperature on creep behavior of soldered joints. Results indicated that the creep resistance of soldered joints of Cu particle enhancement 63Sn37Pb based composite soldered joint was generally superior to that of the conventional 63Sn37Pb soldered joint. At the same time, creep rupture life of the composite soldered joint was declined with increasing temperature and drop faster than that of the conventional 63Sn37 Pb eutectic soldered joint. 相似文献
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