Substrate topography in the micrometer range is reviewed as a modifier of the response of cultured cells and of biocompatibility when implanted into tissues. Characterization methods for substrate topography are discussed, including scanning electron microscopy, profilometry, laser scanning, and confocal microscopy. Because of the current technical limitations in reproducing micron-level topographic details, only one method, ion-beam etching, has been found suitable for texturing substrates on nonplanar surfaces.

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A simple comparative technique to characterize surface electrical resistance of small metallic samples at submillimeter wavelengths is presented. A quasioptical hemispherical resonator, fed by an optically pumped far-infrared laser is used, with the sample serving as the plane mirror. The cavity developed combines a small beam size at the sample, enabling measurements on samples with widths as small as 5 mm, with a large quality factor Q, so that surface resistance losses are readily measurable. This cavity uses a simple new geometry that feeds the cavity through a single small coupling hole that also serves as a system of monitoring energy storage in the cavity by means of a single external beamsplitter. An alternate approach of inserting an internal beamsplitter into the resonator was found to be unacceptable due to excessive losses and alignment problems.

In this study we have combined a method of calculating radiation induced damage to solar cells using Non‐Ionizing Energy Loss (NIEL), with models of Earth orbiting radiation in arbitrary orbits, to assess the lifetime of solar cells. This paper provides a comparison of the NIEL technique to results from the JPL Radiation Handbook, and to actual space experimental damage results. In addition, we discuss ways of extending the calculation to newer solar cell materials, as well as environments outside of the Earth's orbit. Copyright © 2000 John Wiley & Sons, Ltd.

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