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无铅回流焊后跨线碳膜裂纹的探讨
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作者 李春明 《印制电路信息》 2012年第S1期106-114,共9页
针对PCB在过无铅回流焊后跨线位碳膜出现裂纹问题进行分析探讨,通过从调整碳膜参数、不同碳膜厚度对比、不同碳膜性能对比的结果,得出结论:碳膜开裂与油墨性能和设计有直接的关系。最终调整碳膜工艺参数和更改线路设计等方案,能有效改... 针对PCB在过无铅回流焊后跨线位碳膜出现裂纹问题进行分析探讨,通过从调整碳膜参数、不同碳膜厚度对比、不同碳膜性能对比的结果,得出结论:碳膜开裂与油墨性能和设计有直接的关系。最终调整碳膜工艺参数和更改线路设计等方案,能有效改善碳膜裂纹的问题。 展开更多
关键词 无铅回流焊 碳膜裂纹
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A new measurement method of crack propagation rate for brittle rock under THMC coupling condition 被引量:7
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作者 Wei YI Qiu-hua RAO +1 位作者 Zhuo LI Qing-qing SHEN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2019年第8期1728-1736,共9页
A new electrical method of conductive carbon-film(with waterproof and anticorrosion ability)was proposed to continuously measure crack propagation rate of brittle rock under THMC coupling condition.A self-designed cou... A new electrical method of conductive carbon-film(with waterproof and anticorrosion ability)was proposed to continuously measure crack propagation rate of brittle rock under THMC coupling condition.A self-designed coupling testing system was used to conduct THMC coupling fracture tests of the pre-cracked red sandstone specimens(where the temperature is only changed)by this new electrical method of conductive carbon-film.Calculation results obtained by the energy method coincide well with the test results.And the higher the temperature is,the earlier the crack is initiated and the larger the crack propagation rate and accelerated velocity are,which can prove the validity of the new electrical method.This new electrical method has advantages of continuously measuring crack propagation rate over the conventional electrical,optical and acoustic methods,and can provide important basis for safety assessment and cracking-arrest design of deep rock mass engineering. 展开更多
关键词 crack propagation rate electrical method of conductive carbon-film thermo-hydro-mechanical-chemical coupling energy method brittle rock
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