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Large aluminum electrolytic capacitors are usually selected by considering factors such as cost effectiveness (more ripple current or capacitance per dollar), space effectiveness (less volume per dollar), and performance (more useful life at actual application temperature and voltage). These factors have been addressed in recent years as most major manufacturers have responded with improvements in ripple current ratings, new electrolyte systems, high capacitance foils, and rigorous cost controls. The focus of this paper is some of the constructional and application factors affecting the performance of large electrolytic capacitors. An aluminum electrolytic capacitor must be considered as a complete system since the internal failure mechanisms are multiple and complex in their interactions. It is also shown that the choices made by the circuit designer can be informed and improved by understanding the tradeoffs between different capacitor series, circuit design parameters and equipment design enhancements. This understanding can result in designs that are both reliable and cost-effective.

Marx generators have been built with a wide span of physical size and output capability, ranging from circuit board scale devices of a few stages up to systems capable of producing many Megavolts and occupying entire buildings. Our focus in this paper is the development of a capability to explore compact Marx generator (CMG) devices, where we arbitrarily define a CMG to be an apparatus consuming less than 0.5 m/sup 3/ (excluding the charging and control systems). We report the development of a laboratory system that incorporates a shielded test stand with battery-powered high voltage charging supplies and a computer based control system with a graphical user interface. We briefly discuss a demonstration of the test bed capability with results from a modular CMG we have constructed.

Structural and thermodynamic properties of equilibrated ultrathin Pd-Au, Cu-Ag, and Co-Ag alloys on Ru(0001) were studied and are comparatively discussed. These studies provide a framework for a detailed understanding of the energetics of surface alloy formation.Additionally, the differences between the two bulk immiscible systems (Cu-Ag and Co-Ag) and the bulk miscible Pd-Au system are discussed.

We report on the structure and composition of codeposited thin Ag and Cu films on a Ru(0001) substrate. All three metals are immiscible in their bulk forms, however, monolayer films of Ag and Cu are observed to alloy on Ru(0001). In the dilute Cu case, preferential formation of the alloy is found. With increasing Cu concentration, domains of the alloy are formed with characteristic shapes. These data point to a mechanism of alloy formation driven by strain relief of the overlayer film. Details of the structure and composition of the film can be understood within this picture.