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In this work, we report on the performance of graphene field-effect transistors (GFETs) in which the extrinsic transit frequency (f T) and maximum frequency of oscillation (fmax) showed improved scaling behavior with respect to the gate length (Lg). This improvement was achieved by the use of high-quality graphene in combination with successful optimization of the GFET technology, where extreme low source/drain contact resistances were obtained together with reduced parasitic pad capacitances. GFETs with gate lengths ranging from 0.5 µm to 2 µm have been characterized, and extrinsic f T and fmax frequencies of up to 34 GHz and 37 GHz, respectively, were obtained for GFETs with the shortest gate lengths. Simulations based on a small-signal equivalent circuit model are in good agreement with the measured data. Extrapolation predicts extrinsic f T and fmax values of approximately 100 GHz at Lg=50 nm. Further optimization of the GFET technology enables fmax values above 100 GHz, which is suitable for many millimeter wave applications.

The effect of different extracts of leaves and fruits of Moringa oleifera Lam. (Moringaceae) on gastric and duodenal ulcers was evaluated by using different gastric ulcer models and cysteamine-induced duodenal ulcer method. The leaf extracts (500 mg=kg, p.o.) of Moringa oleifera showed gastric ulcer healing effect in acetic acid-induced chronic gastric ulcers. The acetone extract and methanol extract of the leaves produced gastric antisecretory effect in pylorus-ligated rats and showed gastric cytoprotective effect in ethanol-induced and indomethacin-induced gastric ulcers. The leaf extracts also produced a significant reduction of stress-induced gastric ulcers and cysteamine-induced duodenal ulcers. None of the extracts of the fruits showed any significant antiulcer effect. It was concluded that leaves of Moringa oleifera increase healing of gastric ulcers and also prevent the development of experimentally induced gastric ulcers and duodenal ulcers in rats.

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