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The shear strength and aging characteristics of 63Sn–37Pb solder bumps were characterized with variation in solder ball and
UBM pad sizes. The shear strength increased with shorter effective crack size,a
effs
which was determined with the solder ball and pad sizes. The shear strength of the solder bumps on Au/Ni/Cu and Ni/Cu did
not change significantly with reflow time. Substantial decrease in the shear strength occurred for the solder bumps formed
on Au/Ni/Cu with aging treatment, and the shear strength after aging was also related to the bump shape which was determined
with the solder ball and pad sizes. 相似文献
2.
Development and application of gas hydrate reservoir simulator based on depressurizing mechanism 总被引:6,自引:0,他引:6
Won-Mo Sung Dae-Gee Huh Byong-Jae Ryu Ho-Seob Lee 《Korean Journal of Chemical Engineering》2000,17(3):344-350
Natural gas hydrates are known to occur in vast quantities at the ocean floor or in permafrost regions. In-situ hydrate contains
great volumes of methane gas, which indicates a potential future energy resource. In this study, we have developed a three-dimensional,
multi-phase (gas, water, and hydrate) flow finite-difference model by using implicit pressure explicit saturation technique
in order to investigate simultaneous flow through ice-liked hydrate reservoir. The developed model is based on the depressurizing
method as producing mechanism. The model evaluates local gas generation dissociated from the hydrate with the aid of kinetic
dissociation theory proposed by Kim-Bishnoi. The computation of kinetic dissociation uses the empirical dissociation rate
as a function of specific surface area between phases and pressure difference. With the developed model, a one-dimensional
system has been simulated for analyzing the production performance of a hydrate reservoir and for investigating the effect
of hydrate saturation on absolute permeability and relative permeability characteristics. Also, for the three-dimensional
field-scaled reservoir system, a number of numerical exercises have been conducted to understand the effect of mass transfer
and to characterize the flowing mechanism under the conditions of increased permeability resulting from the dissociation hydrate. 相似文献
3.
Since the development of microcolumn system, it attracted much attention because multiple microcolumns can be assembled into arrayed form, which is expected to generate multiple electron beams and overcome the disadvantage of electron beam inspection equipments, low throughput [1], [2] and [3]. However, it is not easy to apply a microcolumn to the practical inspection or testing equipment since its scanning area is too small. Even if the arrayed operation using multiple microcolumns can overcome this limit, it requires complicated supporting systems and related technologies to operate a number of microcolumns simultaneously. Therefore, we tried to modify microcolumn design itself so that it can have a large field of view. In this work, two kinds of modified columns will be suggested and the preliminary results showing their performance of scanning large area will be discussed. 相似文献
4.
In the periodic repainting of steel bridges, often the steel surface has to be prepared by using power tools to remove surface contaminants, such as deteriorated paint film and rust, and to increase the adhesive strengths of the paint films to be applied newly. Surface preparation by bristle roll-brush grinding, which is a type of power tool, may additionally introduce compressive residual stress and increase the fatigue resistance of welded joints owing to the impact of rotating bristle tips. In this study, fatigue tests were conducted for longitudinally out-of-plane gusset fillet welded joints and transversely butt-welded joints to evaluate the effect of bristle roll-brush grinding prior to repainting on the fatigue resistance of the welded joints. The test results showed that bristle roll-brush grinding introduced compressive residual stress and significantly increased fatigue limits by over 50%. 相似文献
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