Electrical characterization of metal-oxide-semiconductor capacitors with anodic and plasma-nitrided oxides A quantitative analysis of stress-induced leakage currents and extraction of trap properties in 6.8 nm ultrathin silicon dioxide films

The adhesion of fine particles onto bubbles in flotation was studied on the basis of surface charge measurement3 of the bubbles and particles.The surface charges of the bubbles were measured by the use of a micro-electropheresis apparatus devised in our previous study and the mechanism of the bubble charging was studied under various experimental conditions. In distilled water, the bubbles were negatively charged and the iso-electric point appeared at pH = 2.5. The surface charges of the bubbles in the surfactant solution were determined by the surfactant molecules adsorbed at the surface and depend strongly on the values of pH.The flotation efficiency of latex particles (0.923 pin) was found to be strongly influenced by the surface charges of both the particles and the bubbles. The force between the particle and the bubble was estimated from the observation of the particle attachment to the bubble surface, and a simple equation including the effects of the hydrodynamic and surface charge interactions was proposed to determine the floatability limit.L'adhCsion de particules fines dans des bulles en tlottation a Ct C etudiee sur la base de mesures de charge de surface des bulles et des particules.Les charges de surface des bulles ont kte mesurees au nroyen d'un appareillage de micro-dectrophorese c o n y danr nos etudes anterieures, et on a Ctudit le mecanisme de chargement des bulles dans des conditions experimentales variees. Dans de I'eau distillte, les bulles ont CtC chargees negativement et le point iso-blectrique est apparu au pH de 2.5. Les charges de surface de bulles dans la solution de surfactant ont ttC dkterminees par les molkcules de surfactant adsorbkes B la surface et elles dCpendent fortement des valeurs du pH. On a trouve que I'effcacitC de flottaison des particules de latex (0,923 pm) Ctaient fortenient influencee par les charges de surface a la fois des particules et des bulles. La force entre les particules et les bulles a cte estimee 2 partir de I'observation de la liaison des particules a la surface des bulles, et on propose une equation simple incluant les effets des interactions des charges de surface et de I'hydrodynamique pour determiner la limite de flottabilitk.

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Friction is ubiquitous in all aspects of everyday life and has consequently been under study for centuries. Classical theories of friction have been developed and used to successfully solve numerous tribological problems. However, modern applications that involve advanced materials operating under extreme environments can lead to situations where classical theories of friction are insufficient to describe the physical responses of sliding interfaces. Here, we review integrated experimental and computational studies of atomic-scale friction and wear at solid-solid interfaces across length and time scales. The influence of structural orientation in the case of carbon nanotube bundles, and molecular orientation in the case of polymer films of polytetrafluoroethylene and polyethylene, on friction and wear are discussed. In addition, while friction in solids is generally considered to be athermal, under certain conditions thermally activated friction is observed for polymers, carbon nanotubes and graphite. The conditions under which these transitions occur, and their proposed origins, are discussed. Lastly, a discussion of future directions is presented.

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