A MEMS cantilever IR detector that repetitively lifts from the surface under the influence of a saw-tooth electrostatic force, where the contact duty cycle is a measure of the absorbed IR radiation, is analyzed. The design is comprised of three parallel conducting plates. Fixed buried and surface plates are held at opposite potential. A moveable cantilever is biased the same as the surface plate. Calculations based on energy methods with position-dependent capacity and electrostatic induction coefficients demonstrate the upward sign of the force on the cantilever and determine the force magnitude. 2D finite element method calculations of the local fields confirm the sign of the force and determine its distribution across the cantilever. The upward force is maximized when the surface plate is slightly larger than the other two. The electrostatic repulsion is compared with Casimir sticking force to determine the maximum useful contact area. MEMS devices were fabricated and the vertical displacement of the cantilever was observed in a number of experiments. The approach may be applied also to MEMS actuators and micromirrors.

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The biochemical composition of normal human brain tissue in comparison with that of brain-tumour tissue was studied and diagnosed by means of the attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy technique. IR spectroscopy is a potential histopathological tool for detecting and diagnosing cancer and other diseases. In the study, the amounts of lipids, protein, and water in different brain-tissue specimens from patients of various ages were determined from their ATR-FTIR spectra upon analysing a combination of the pure-component spectra. A higher level of biocomponents was observed in the normal tissue, and in particular, more fluid (water) was contained in benign tumours. The age of patients was found to play an important role; patient age exhibited a direct correlation with the concentration of biocomponents, with increasing age corresponding to a reduction in lipids and proteins. These results demonstrate the diagnostic potential of ATR-FTIR spectroscopy for evaluating brain tumours in terms of its ability to distinguish between normal tissue and tumours in vivo and afford real-time intraoperative diagnosis.