This paper describes the methods using bonded cup wheels for grinding toroidal and cylindrical SiC mirrors with large curvature radii. Since the angle between the cutting direction of bonded abrasives and feed direction of the cup wheel is about 90 °, it is possible to obtain a surface with very low surface roughness independent of the direction of measurement. Toroidal mirrors, circular and el...

a rahalt-chromium (Co-Cr) alloy using a centrifugal shooting type polishing machine. In tha present work, we examined the effects of the texture of polishing particle and polishing time on the surface roughness of Co-Cr alloy cast specimens. Nine differcnt textures of polishing par'ticle were investigated wiLh respect to core material and paTticle abrasiveness: three (lifferent elastic body cer...

We present a new finishing process that is capable of locally shaping and polishing optical surfaces of complex shapes. A fluid jet system is used to guide a premixed slurry at pressures less than 6 bars to the optical surface. We used a slurry comprising water and 10% #800 SiC abrasives (21.8 mum) to reduce the surface roughness of a BK7 sample from 350 to 25 nm rms and to vary the shape of a ...

Along with the remarkable growth in complexity of semiconductor fabrication technology, chemical mechanical planarization (CMP) has evolved and become progressively more sophisticated over years, enabling implementation novel integration schemes. This paper discusses current research development trends one specific aspect CMP namely, ceria particle usage for advanced technology nodes provides s...

OBJECTIVES This study assessed total and free fluoride concentrations in samples of toothpaste from Brunei, Cambodia, Laos, the Netherlands and Suriname, and investigated the labelling practices of the respective manufacturers. MATERIALS AND METHODS Convenience samples were bought in the five countries and sent for analysis to the Netherlands. Levels of total and free available fluoride were ...

Extant rhinos are the largest extant herbivores exhibiting dietary specialisations for both browse and grass. However, the adaptive value of the wear-induced tooth morphology in rhinos has not been widely studied, and data on individual cusp and tooth positions have rarely been published. We evaluated upper cheek dentition of browsing Diceros bicornis and Rhinoceros sondaicus, mixed-feeding R. ...