No abstract

This investigation examined the complicated impedance characteristics of the human tooth root canal using a mimic system that comprised a cylindrical tubule and 5% agar-gel. The in vitro impedance measurements of root canals were made using a frequency response analyzer and a tubule filled with distilled water or normal saline. An equivalent circuit model of this bioelectric system was proposed; it closely corresponds to the experimental results. On the basis of the proposed equivalent circuit model, the experimental results can be explained reasonably and the effect of the filling of the canal with the electrolytes can be clearly understood. The modified impedance quotient ͑Q͒ and the variation ratio of the impedance quotient ͑S Q ͒ are taken as the useful indices of the apex. Different impedance behaviors have been identified from Q values in under-apex and over-apex regions, respectively. The S Q was Ͻ0.15 at the apex location as well as in the overapex region for all electrolytes and could be used to eliminate the effect of the electrolytic conductivity. This study elucidates the complicated electric mechanisms of electrolytic systems and improves clinical applications in the endodontic treatment.

Via filling is a critical process for metallization of a through-silicon via (TSV) in a 3D MEMS device. This study uses a rotating disc electrode (RDE) at 1000 rpm, 100 rpm and 10 rpm to simulate the mass-transfer environment of metallization on the wafer surface, at the bottom of shallow vias and the deep vias, respectively. RDE techniques display the difference of suppression action among three rotation speeds clearly. The calculated filling power is higher over a wide surface current density using the plating bath of 50 g L −1 Cu 2+ than that of 25 or 75 g L −1 Cu 2+ . TSV filling in a wafer-segment scale, with 15 μm via diameter and 150 μm via depth, verifies the performance predicted by the RDE techniques.

No abstract

No abstract