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基于小波分析的CO_2弧焊电源工艺动特性的评定 被引量:5
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作者 张晓囡 李俊岳 +2 位作者 李桓 杨立军 黄石生 《机械工程学报》 EI CAS CSCD 北大核心 2002年第1期112-116,共5页
在阐述了信号(函数)的奇异性检测及其与小波变换模极大值关系的基础上,针对熔滴短路过渡的CO2焊焊接电流信号,研究了信号局部奇异性的小波分析检测方法,选择了合适的小波函数,提取了焊接电流信号的波形特征。通过弧焊电源工艺... 在阐述了信号(函数)的奇异性检测及其与小波变换模极大值关系的基础上,针对熔滴短路过渡的CO2焊焊接电流信号,研究了信号局部奇异性的小波分析检测方法,选择了合适的小波函数,提取了焊接电流信号的波形特征。通过弧焊电源工艺动特性的测试试验表明,由所提取的电流信号波形特征的概率密度分布图中,能够得到与电源工艺动特性相关的特征信息,验证了小波分析方法对提取电源工艺动特性的评定特征信息的有效性。 展开更多
关键词 小波分析 奇异性检测 模极大值 弧焊电源 工艺动特性 焊接 CO2焊
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Rheo-diecasting of AZ91D magnesium alloy by taper barrel rheomoulding process 被引量:5
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作者 杨柳青 康永林 +2 位作者 张帆 丁瑞华 李炯 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第6期966-972,共7页
A self-developed taper barrel rheomoulding(TBR)machine was introduced,and the rheo-diecasting process was implemented by combining TBR machine with the high pressure die casting(HPDC)machine.Microstructural characteri... A self-developed taper barrel rheomoulding(TBR)machine was introduced,and the rheo-diecasting process was implemented by combining TBR machine with the high pressure die casting(HPDC)machine.Microstructural characteristics of the rheo-diecasting components were investigated at different rotation speeds.Flow characteristics and microstructural evolution of the semi-solid slurry during the rheo-diecasting process were analyzed and the mechanical properties of the rheo-diecasting components were studied.The experimental results show that the process is able to obtain such components in which the primaryα-Mg particles are fine,nearly spherical and uniformly distributed in the matrix.When the rotation speed of internal taper barrel is 700 r/min,the primaryα-Mg particles get a mean diameter of about 45μm and a shape factor of about 0.81.The magnesium alloy melt has complex stirring-fixed flow characteristics when flowing in TBR machine.Compared with conventional die-casing process,the rheo-diecasting process can improve the mechanical properties of components;especially,the elongation is improved by 80%. 展开更多
关键词 AZ91D magnesium alloy RHEO-DIECASTING MICROSTRUCTURE flow characteristics mechanical properties
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