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刚挠结合板模拟回流焊后分层改善分析
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作者 曹杰 唐鹏 《印制电路信息》 2023年第S01期284-288,共5页
本文记录了某款刚挠结合板在模拟回流焊测试后出现的分层异常,并进行分层改善分析。通过FA分析,确认回流后分层为层压分层,对比层压生产加工流程、层压参数、材料叠层差异等,找到造成层压分层的显著因子——上压温度点。针对显著因子设... 本文记录了某款刚挠结合板在模拟回流焊测试后出现的分层异常,并进行分层改善分析。通过FA分析,确认回流后分层为层压分层,对比层压生产加工流程、层压参数、材料叠层差异等,找到造成层压分层的显著因子——上压温度点。针对显著因子设计试验进行专项改善,成功改善层压分层问题。 展开更多
关键词 刚挠结合板 模拟回流焊 层压分层
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覆盖膜保护方式内置元器件PCB制作技术研究
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作者 林启恒 卫雄 +1 位作者 林映生 陈春 《印制电路信息》 2016年第A02期228-233,共6页
内置元器件PCB是指将电阻、电容等元器件埋入PCB内部形成的产品,有效缩小连接引线长度,减少表面焊接元器件及焊接数量,确保焊接品质;同时能有效保护元器件,减轻元件间的电磁干扰,保证信号传输稳定性,提高IC性能。传统的内置元器... 内置元器件PCB是指将电阻、电容等元器件埋入PCB内部形成的产品,有效缩小连接引线长度,减少表面焊接元器件及焊接数量,确保焊接品质;同时能有效保护元器件,减轻元件间的电磁干扰,保证信号传输稳定性,提高IC性能。传统的内置元器件PCB制作工艺存在内层棕化膜高温变色、棕化后停留时间超24小时导致压合分层的品质风险。文章分析了现有内置元器件PCB加工工艺的缺点,提出覆盖膜保护方式内置元器件PCB工艺,有效改善上述工艺难点,提升产品品质。 展开更多
关键词 内置元器件 印制电路板 棕化 层压分层 覆盖膜保护
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A Model of Turbulent-Laminar Gas-Liquid Stratified Flow
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作者 李卫东 赵钦新 李荣先 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2001年第2期129-132,共4页
The time-dependent liquid film thickness and pressure drop are measured by using parallel-wire conduc tance probes and capacitance differential-pressure transducer. A mathematical model with iterative procedure to cal... The time-dependent liquid film thickness and pressure drop are measured by using parallel-wire conduc tance probes and capacitance differential-pressure transducer. A mathematical model with iterative procedure to calculate holdup and pressure drop in horizontal and inclined gas-liquid stratified flow is developed. The predictions agree well with over a hundred experimental data in 0.024 and 0.04 m diameter pipelines. 展开更多
关键词 two-phase flow stratified flow HOLDUP pressure drop
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Failure Analysis in Graphite Epoxy Composite Laminates
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作者 Olanrewaju Aluko 《Journal of Mechanics Engineering and Automation》 2014年第10期813-819,共7页
The present analysis was performed to obtain bearing strength for pinned joints in uni-directional graphite epoxy composite laminates using characteristic curve model. The characteristic dimensions used to determine t... The present analysis was performed to obtain bearing strength for pinned joints in uni-directional graphite epoxy composite laminates using characteristic curve model. The characteristic dimensions used to determine the characteristic curve were evaluated using a two-dimensional finite element model that was developed in ANSYS14.5 Software. Also, two-dimensional finite element stress analysis was developed to determine the stress distribution needed to evaluate the failure. Tsai-Wu failure criterion was used in the analysis with the characteristic curve to predict bearing strength. The results of the analysis showed good agreement with experimental data. 展开更多
关键词 Bearing strength COMPOSITE finite element experiment.
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