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The fate of the OP nerve agent isopropyl methylphosphonofluoridate (sarin) on granular activated and metal‐impregnated activated carbons that are used in gas‐mask filters was investigated by means of 31P magic‐angle‐spinning (MAS) NMR spectroscopy. The results show that most of the adsorbed sarin on extensively dried carbons decomposes with a half‐life of 5–12 days. A MAS‐NMR signal of the degradation product isopropyl methylphosphonic acid (IMPA) appears in the spectra of sarin on non‐impregnated carbons. The IMPA signal is not visible in the spectra from metal‐impregnated carbons, probably due to strong binding of the acid molecule to paramagnetic Cr3+ and Cu2+ ions. Exposure of BPL and ASC carbons to air of 53% relative humidity shortens the degradation time by approximately an order of magnitude. Wetting shortens the half‐life of sarin on BPL carbon to approximately 2 hours. 相似文献
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Exposed in natural outcrops near the Duibian Village, Jiangshan County, Zhejiang Province, China, the Duibian B section is proposed as the boundary stratotype for the base of an unnamed stage termed provisionally Cambrian Stage 9. The proposed position of the GSSP is 108.12 m above the base of the Huayansi Formation, at a horizon coinciding with the first appearance of the cosmopolitan agnostoid trilobite Agnostotes orientalis. This horizon coincides also with the first appearance of the cosmopoli-tan polym... 相似文献
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