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塑料球栅阵列封装PBGA的可靠性分析中,考虑封装过程中SnAgCu焊料与铜焊盘界面间产生的金属间化合物(Intermetallic compound,IMC)的影响,并引入内聚力模型(Cohesive zone model,CZM),利用ANSYS对热循环作用下焊点/IMC界面的脱层开裂情况进行研究.结果表明:热循环作用下,在封装器件中焊点承受较大的应力应变,且远离中心的外侧焊点具有比内侧焊点更大的应力应变.IMC的存在极大的降低了焊点的可靠性.界面分层最先发生在最外侧的IMC/焊点界面的两端,随着热循环次数的增加,分层逐渐沿着界面两端向里扩展.在热循环的前几个阶段,各个界面的最大损伤值增大较快,随着热循环的继续加载,界面最大损伤值逐渐趋于稳定.整个过程中四号焊点界面的损伤值始终最大. 相似文献
33.
Modification of nano-fibriform silica by dimethyldichlorosilane 总被引:1,自引:0,他引:1
The modification of nano-fibriform silica by dimethyldichlorosilane was studied by transmission electron microscopy, X-ray powder diffraction, infrared spectroscopy, Raman spectroscopy, physical N2 adsorption techniques, differential thermal and thermogravimetric analysis, scanning electron microscopy, and elemental analyzer.The results show that dimethyl silane derivatives have been successfully covalently grafted on nano-fibriform silica. The polarity of the modified product decreases with the substitution of -OH groups by siloxyl groups. Therefore, the modified product can be easily dispersed in organic solvent and its compatibility with organic molecules is improved. After modification the pore volume decreases and the ductility greatly increases, indicating that the modified product is of a higher strength than before. The study demonstrates that the modified product can be used as an ideal additive to reinforce the strength of organic materials. 相似文献
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Determination of five sesquiterpenoids in Xingnaojing injection by quantitative analysis of multiple components with a single marker 下载免费PDF全文
Weidong Pan Lixin Yang Weihong Feng Limei Lin Chun Li Guofeng Gan Junhong Fan Jigao Zou Zhimin Wang Haifeng Pan 《Journal of separation science》2015,38(19):3313-3323
A quantitative analysis of multiple components with a single‐marker method was established for the simultaneous determination of five sesqutiterpenoids in Xingnaojing injection. This method was established with Xingnaojing injection determined by high‐performance liquid chromatography coupled with diode array detection. The durability and system suitability of the established method were evaluated, and the reliable relative correction factors were obtained with curdione selected as an internal reference. The contents of the five components in all Xingnaojing injections were determined by external standard method and the contents of curcumenone, curcumenol, curzerenone, and germacrone were also calculated with the obtained relative correction factors. Then, relative error was investigated to estimate the difference of the two methods. As a result, the established new method possesses good adaptability, and there is no significant difference between the two methods, except for the content of curzerenone in eight samples. To put the established method into practice, the limits of quantitation of the established method of the five components were proposed and defined. Thus, the developed methodology can also be utilized to the quality evaluation of Xingnaojing injection, in spite of the difference found in the content of curzerenone between the external standard method and the newly established method. 相似文献
36.
Hydrothermal Synthesis of Nickel Phosphate Nanorods for High‐Performance Flexible Asymmetric All‐Solid‐State Supercapacitors 下载免费PDF全文
Junhong Zhao Shaomei Wang Zhen Run Guangqin Zhang Weimin Du Huan Pang 《Particle & Particle Systems Characterization》2015,32(9):880-885
Ni20[(OH)12(H2O)6][(HPO4)8(PO4)4]·12H2O nanorods are successfully synthesized via a one‐pot hydrothermal reaction. A high‐performance flexible asymmetric all‐solid‐state supercapacitor based on the obtained Ni20[(OH)12(H2O)6][(HPO4)8(PO4)4]·12H2O nanorods (positive electrode) and graphene nanosheets (negative electrode) is successfully assembled. It is the first report of this nanomaterial applied for all‐solid‐state supercapacitors. Interestingly, a maximum volumetric energy density of 0.446 mW h cm?3 at a current density of 0.5 mA cm?2 and a maximum power density of 44.1 mW cm?3 at a current density of 6.0 mA cm?2 are achieved by the as‐assembled device. What's more, the device also shows excellent mechanical flexibility and little capacitance change after over 5000 charge/discharge cycles at a current density of 0.5 mA cm?2. 相似文献
37.
Myogloblin, a well-known metalloprotein, was immobilized on a gold surface using various chemical linkers to investigate the length effect of chemical linker on the electron transfer in protein layers, because chemical linkers play roles in the pathway that transfers the electron from the protein to the gold substrate and act as protein immobilization reagents. Chemical linkers with 2, 6, 11, and 16 carbons were utilized to confirm length-effects. The immobilization of protein and chemical linker was validated with surface plasmon resonance (SPR) and atomic force microscopy (AFM). The electrochemical property was evaluated by cyclic voltammetry (CV) and chronocoulometry (CC). In those results, redox peaks of immobilized protein were controlled via the length of chemical linkers, and it could be directly applied to the realization of bioelectronic device. 相似文献
38.
{[Cu(6)(TTTMB)(8)(OH)(4)(H(2)O)(6)]·8(NO(3))·34.5H(2)O}(n) can reversibly transform to {[Cu(6)(TTTMB)(8)I(3)]·9I·26H(2)O}(n) upon a single crystal to single crystal process. The transformation is accompanied by the formation of weak Cu(2+)I(-) interactions and changes in the coordination numbers, as well as modulation in their properties. 相似文献
39.
以含不同倾角预制裂纹的长方形板状红砂岩为研究对象,采用分离式霍普金森压杆沿试样宽度方向施加冲击荷载,使用高速摄像机记录裂纹扩展过程,获得试样的裂纹路径特征以及动态压缩强度和动态弹性模量,利用筛分统计法分析试样碎块分布特征,结合分形理论定量描述试样破碎程度及特点,探讨中应变率条件下含裂隙试样裂纹扩展模式与动态力学性质和破碎程度的相互关系。研究结果表明,应变率较高时试样会更多地出现远场裂纹和离层裂纹,并且相比相关低应变率实验结果,中应变率范围内试样破坏模式及裂纹分布情况随应变率的变化规律是不同的。随着应变率的提高,试样大体上从1条拉伸裂纹的临界破坏演变成X形剪切裂纹为主的复杂裂隙网络,并且不同角度预制裂隙对于这种裂纹扩展模式的演变有重要影响。在预制裂纹倾角一定的情况下,岩样动态压缩强度和动态弹性模量表现出明显的应变率效应,不同角度预制裂纹对于试样的应变率敏感性有显著影响。随裂纹倾角的增大,试样的动态强度、动态弹性模量和分形维数表现出的变化趋势具有一定的相似性,大体呈现先减小后增大的趋势,裂纹倾角为45°的试样的动态压缩强度、动态弹性模量和分形维数均为最小。随应变率的升高,不同预制裂纹倾角的试样碎块分布更加分散,应变率越高,预制裂纹倾角对于岩石冲击破碎程度、分形维数的影响越显著。
相似文献40.