N-nitrosamines are strong carcinogens for humans. This paper gives an overview of the nitrosmaines in cigarette smoke including the formation, the harmfulness, the analytical methods of the nitrosmaines and the adsorp...N-nitrosamines are strong carcinogens for humans. This paper gives an overview of the nitrosmaines in cigarette smoke including the formation, the harmfulness, the analytical methods of the nitrosmaines and the adsorptions and degradations of N –nitrosamines.展开更多
The factors and mechanisms of oxidative degradation of three organophosphorus pesticides （dichlorvos, methamidophos and phoxim） were studied with sodium percarbonate （SPC） as a solid oxidant. The result showed tha...The factors and mechanisms of oxidative degradation of three organophosphorus pesticides （dichlorvos, methamidophos and phoxim） were studied with sodium percarbonate （SPC） as a solid oxidant. The result showed that SPC has highly activity in degrading these organophosphous pesticides. The most efficient degradation of pesticides occurred under basic conditions and the degradation rates increased with time extension and high temperature. The degradation of organophosphorus pesticides was expected to get even better results at lower initial concentration. Furthermore, we analyzed the intermediate products by NMP, spectrometry. On the basis of the analytical result, the oxidative degradation mechanism was proposed for each organophosphous pesticide. It is significant to understand the environment chemistry of organophosphorus pesticides in environmental system.展开更多
A comparison of thermal and photochemical degradation of poly （lactic acid） film materials （10/am） containing nanosilver are studied by FTlR （Fourier transform infrared） spectroscopy and DSC （differential scann...A comparison of thermal and photochemical degradation of poly （lactic acid） film materials （10/am） containing nanosilver are studied by FTlR （Fourier transform infrared） spectroscopy and DSC （differential scanning calorimetry）. Rates of thermal and photochemical degradation are determined by measuring the relative changes of absorbance （A/Ao） of selected bands in PLA （polylactic acid） spectra. Comparison of the effect of both degradation on PLA structure showed that nanosilver act as a stabilizer for photodegradation at 254 nm. As oppose, thermal degradation at 80 ~C indicate, that nanosilver accelerates PLA degradation at the temperature. Glass transition and crystallization/melting processes occurring in PLA and PLA/Ag nanocomposites during both degradation processes were also compared.展开更多
文摘N-nitrosamines are strong carcinogens for humans. This paper gives an overview of the nitrosmaines in cigarette smoke including the formation, the harmfulness, the analytical methods of the nitrosmaines and the adsorptions and degradations of N –nitrosamines.
文摘The factors and mechanisms of oxidative degradation of three organophosphorus pesticides （dichlorvos, methamidophos and phoxim） were studied with sodium percarbonate （SPC） as a solid oxidant. The result showed that SPC has highly activity in degrading these organophosphous pesticides. The most efficient degradation of pesticides occurred under basic conditions and the degradation rates increased with time extension and high temperature. The degradation of organophosphorus pesticides was expected to get even better results at lower initial concentration. Furthermore, we analyzed the intermediate products by NMP, spectrometry. On the basis of the analytical result, the oxidative degradation mechanism was proposed for each organophosphous pesticide. It is significant to understand the environment chemistry of organophosphorus pesticides in environmental system.
文摘A comparison of thermal and photochemical degradation of poly （lactic acid） film materials （10/am） containing nanosilver are studied by FTlR （Fourier transform infrared） spectroscopy and DSC （differential scanning calorimetry）. Rates of thermal and photochemical degradation are determined by measuring the relative changes of absorbance （A/Ao） of selected bands in PLA （polylactic acid） spectra. Comparison of the effect of both degradation on PLA structure showed that nanosilver act as a stabilizer for photodegradation at 254 nm. As oppose, thermal degradation at 80 ~C indicate, that nanosilver accelerates PLA degradation at the temperature. Glass transition and crystallization/melting processes occurring in PLA and PLA/Ag nanocomposites during both degradation processes were also compared.
