A new low cost bare-chip LSI inter-connection lead-less-chip technology was installed by Au ball-bump (1976) and Ag-Sn solder on the printed wiring board under none flux condition. Au ball-bumps were made on the LSI Al pads directly by conventional wire bonding method and Ag-Sn bumps on the leads of the build-up processed PWB by the solder micro-press punching technology less than 120 microns pads-pitch. This micro-press punching technology has reached the higher stability of 500,000 times continuously at nearly 0.1 sec/piece speed with 50 /spl mu/m thickness soft solder tape. And the diameter of punched-out solder disk was realized at 50 /spl mu/m level on the tips of the PWB pads directly. This lead-less-chip technology of the flip-chip assembly on MCM-L, has the high reliability and the low cost possibility.
This paper presents buckling analysis of the reinforcing bars performed by the finite element method using large deflection theory of layered beam elements. The buckling behavior is considered under monotonic and cyclic loading. Based on the analytical results, several indices such as the buckling stress, the residual stress and the buckling mode are used to characterize the buckling behavior. Based on these results, a stress-average strain relationship of the reinforcing bars is developed accounting for inelastic buckling. The model features a post-buckling softening branch, since the buckling behavior is considered in the form of a material property, which is an easy method to introduce the effect of buckling in the finite element method.
Various types of shear reinforcement are used for example general closed stirrup and reinforcement bar with mechanical anchor. However, most standards and specifications take only the cross-sectional area of the vertical components of the reinforcement components into account when determining their effect, such as on shear crack development and shear strength. Consequently, the full effect of different shear reinforcement shapes on the shear failure behavior of reinforced concrete (RC) beams is not clear. In this study, differences in shear failure behavior of RC beams using three types of shear reinforcement (closed stirrups, U-shaped stirrups, and rod-shaped reinforcements with mechanical anchor) were investigated by carrying out loading experiments. The three-dimensional displacement distribution on the side faces of each beam and the internal crack patterns were obtained. It was clarified that there is a clear difference in internal crack pattern and spreading deformation behavior according to shear reinforcement shape, and this influences the shear strength of the RC beam.
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Thermal desorption behavior of tritium has been investigated for SS316 and F82H irradiated by 580MeV proton (SINQ-target3) up to 5.0 ∼5.9 dpa and 6.3∼9.1 dpa, respectively, in order to understand tritium transport in the irradiated materials. While the tritium release has only one peak at 670 K from irradiated SS316, that has two peaks at 510 K and 670 K from irradiated F82H. Those results indicate that only one kind of trap site exists in the SS316, and at least two kinds of trap site exist in F82H. As the results of tritium transport analysis of tritium release behavior, it was found that the trap site at 670 K for SS316 and F82H could be controlled by the same trap mechanism. As to the chemical form of tritium released from the steels, 1/2 and 1/3 of tritium was release as water vapor form from SS316 and F82H, respectively. It could be attributed to the growth of surface oxide on the metal surfaces during the TDS.
