Punch through effect

Fig. 32.28 An example of ESD damage to an IC. A punch-through effect has occurred that exposes lower layers of a circuit. (From Ref. 113.)...

Effects of space charges (finite e). It is expected that the inclusion of space charges will eliminate current saturation (limiting currents) at the lower and middle branches. These branches are instead expected to meet at another turning point, due to punch through (in this purely electro-diffusional formulation without source terms).5... 

Anomalous rectification [3]. Our aim in this section is to show that under certain conditions development of a nonequilibrium space charge may yield, besides the punch through, some additional effects, unpredictable by the locally electro-neutral formulations. We shall exemplify this by considering two parallel formulations—the full space charge one and its locally electro-neutral counterpart. It will be observed that inclusion of the space charge into consideration enables us to account for the anomalous rectification effect that could not be predicted by the locally electro-neutral treatment. Physical motivation for this study is as follows. 

On the other hand, the pin pile cost was in excess of USD 100 per foot. Though expensive, they did offer a number of advantages that made their use attractive and cost effective. Because pin piles transfer their loads by skin friction, there was no possibility that the pile could fail by punching through into a soft underbed immediately under the founding level. Even the diverse soil conditions found in this site could not dramatically alter construction times. In addition, test piles could prove their effectiveness in advance. 

Where a store is to take post-pallets, or will have internal racking to store pallets, careful calculation is necessary of the load on the feet. They can have a considerable point load, having the effect of punching a hole through the floor finish. 

All operations take place simultaneously in different stations. Sixteen stations were commonly used in earlier machines with outputs between 500 and 1000 TPM and tablet diameters up to 15 mm. Presses with outputs orders of magnitude greater than the above are now widely available. The dies are filled as they pass beneath a stationary feed frame, which may be fitted with paddles to aid material transfer. The die cavities are completely filled and excess ejected prior to compression. Compression involves the movement of both punches between compression rolls, in contrast to single station operations where only the upper punch effects compression. Ejection occurs as both punches are moved away from the die on cam tracks until the tablet is completely clear of the die, at which point it hits the edge of the feed frame and is knocked off the press. Tooling pressure may be exerted hydraulically, rather than through the use of mechanical camming actions, as is the case with machines produced by Courtoy. 

Interestingly, the film behavior was much more predictable when it flowed over the disc surface containing the raised lips arising from the punching operation. Film flow on the alternate side tended to leak through the disc, particularly at lower liquid flows, presumably due to the Coanda effect as liquid negotiated the rounded edge of the holes. 

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