2 дек. 2025 г. — NASA AD-1 (Ames-Dryden-1) is a single-engine experimental aircraft from aviation history featuring wings that can be pivoted up to 60 ...
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Rubidium (Rb ) is a soft, silvery-white metallic element belonging to the alkali metals group, with an atomic number of 37 and the chemical symbol Rb. It is ...