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Shi Xunqing Wang Zhiping John HL Pang Zhang Xueren Nie Jingxu 《Acta Mechanica Sinica》2002,18(3):274-287
In this study, a new unified creep constitutive relation and a modified energy-based fatigue model have been established respectively
to describe the creep flow and predict the fatigue life of Sn−Pb solders. It is found that the relation successfully elucidates
the creep mechanism related to current constitutive relations. The model can be used to describe the temperature and frequency
dependent low cycle fatigue behavior of the solder. The relation and the model are further employed in part II to develop
the numerical simulation approach for the long-term reliability assessment of the plastic ball grid array (BGA) assembly.
The project supported by the National Natural Science Foundation of China (59705008) 相似文献
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Shi Xunqing John HL Pang Yang Qianjin Wang Zhiping Nie Jingxu 《Acta Mechanica Sinica》2002,18(4):356-367
In the present study, a facility, i.e., a mechanical deflection system (MDS), was established and applied to assess the long-term
reliability of the solder joints in plastic ball grid array (BGA) assembly. It was found that the MDS not only quickly assesses
the long-term reliability of solder joints within days, but can also mimic similar failure mechanisms in accelerated thermal
cycling (ATC) tests. Based on the MDS and ATC reliability experiments, the acceleration factors (AF) were obtained for different
reliability testing conditions. Furthermore, by using the creep constitutive relation and fatigue life model developed in
part I, a numerical approach was established for the purpose of virtual life prediction of solder joints. The simulation results
were found to be in good agreement with the test results from the MDS. As a result, a new reliability assessment methodology
was established as an alternative to ATC for the evaluation of long-term reliability of plastic BGA assembly.
The project supported by the National Natural Science Foundation of China (59705008) 相似文献
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王恩耀 《核聚变与等离子体物理》1999,19(2):116-119
报道了HL-1M装置1998年度物理实验的进展情况。主要包括等离子体密度极限,中性束注入加热,离子回旋共振加热,低温杂波离子加热,多发弹丸注入,超声分子束注入等实验的情况。 相似文献
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RE Tribble A Azhari HL Clark CA Gagliardi Y-W Lui AM Mukhamedzhanov A Sattaroy X Tang L Trache V Burjan J Cejpek V Kroha S Piskor J Vincour F Carstoiu 《Pramana》1999,53(3):585-594
S-factors for direct capture reactions can be found at astrophysical energies from asymptotic normalization coefficients which
provide the normalization of the tail of the overlap function. For example the overlap for 8B → 7Be+p defines the S-factor for 7Be (p, γ)8B. Peripheral transfer reactions offer a technique to determine these asymptotic normalization coefficients. As a test of
the technique, the 16O(3He, d)17F reaction has been used to determine asymptotic normalization coefficients for transitions to the ground and first excited
states of 17F. The S-factors for 16O(p, γ)17F calculated from these 17F → 16O+p asymptotic normalization coefficients are found to be in very good agreement with recent measurements. Following the same
technique, the 10B(7Be, 8B)9Be and 14N(7Be, 8B)13C reactions have been used to measure the asymptotic normalization coefficient for 7Be(p, γ)8B. This result provides an indirect determination of S
17(0). 相似文献
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中国环流器新一号装置总体联调 总被引:2,自引:1,他引:1
谈满秋 《核聚变与等离子体物理》1997,17(2):1-8
本文介绍中国环流器新一号装置工程总体联合调试的内容和主要结果。该装置总体联调是非常成功的,获得了重复性很好,环电流平顶宽的稳定平稳的放电波形,这对物理实验的开展非常有利。 相似文献
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