UV-Vis absorption and fluorescence spectroscopy are used to test the quality and changes in the composition of extra virgin olive oil (EVOO) and canola oil (CO) with temperature. The increase of temperature caused a c...UV-Vis absorption and fluorescence spectroscopy are used to test the quality and changes in the composition of extra virgin olive oil (EVOO) and canola oil (CO) with temperature. The increase of temperature caused a change in the molecular structures of both types of oils seen as a gradual decrease of intensity amplitudes of absorption and fluorescence signals. A significant alteration occurred at ≈200°C where almost the main spectra of pheophytin-a, b, carotenoids, lutein and vitamin E in EVOO and linoleic acid and oleic acid in CO disappeared. An independent experiment showed the output of laser changes linearly with the input in oil at constant temperature (i.e., room temperature) where the transmission values of ≈33% and ≈75% are determined for EVOO and CO respectively. However, the transmission through a heated oil exhibited a non-linear behaviour which indicates the molecular optical response to thermal changes. The effect of storage time and adulteration of oils were also evaluated.展开更多
Porites coral in the nearshore waters off Hainan Island can give off yellowish\|green fluorescence under UV laser induction. After fitting the data between rainfall and fluorescent intensity, it can be found that both...Porites coral in the nearshore waters off Hainan Island can give off yellowish\|green fluorescence under UV laser induction. After fitting the data between rainfall and fluorescent intensity, it can be found that both appear in a simply linear equation with a correlation coefficient of 0.78. The model equation can be used to reconstruct the rainfall in the past time by means of the determined fluorescent intensity. The correlation diagram of the determined and calculated or hindcast rainfall shows a synchronous change from 1982 to 1997. The peak positions of the variant curve are usually related to the El’nino year. That means the drought and flood recycles are restrained to some extent by globally environmental changes. Therefore, the coral fluorescent intensity acts as a geochemical proxy for reconstructing the rainfall series in the past hundreds of years and predicting the drought\|flood variant tendency in the future time.展开更多
文摘UV-Vis absorption and fluorescence spectroscopy are used to test the quality and changes in the composition of extra virgin olive oil (EVOO) and canola oil (CO) with temperature. The increase of temperature caused a change in the molecular structures of both types of oils seen as a gradual decrease of intensity amplitudes of absorption and fluorescence signals. A significant alteration occurred at ≈200°C where almost the main spectra of pheophytin-a, b, carotenoids, lutein and vitamin E in EVOO and linoleic acid and oleic acid in CO disappeared. An independent experiment showed the output of laser changes linearly with the input in oil at constant temperature (i.e., room temperature) where the transmission values of ≈33% and ≈75% are determined for EVOO and CO respectively. However, the transmission through a heated oil exhibited a non-linear behaviour which indicates the molecular optical response to thermal changes. The effect of storage time and adulteration of oils were also evaluated.
文摘Porites coral in the nearshore waters off Hainan Island can give off yellowish\|green fluorescence under UV laser induction. After fitting the data between rainfall and fluorescent intensity, it can be found that both appear in a simply linear equation with a correlation coefficient of 0.78. The model equation can be used to reconstruct the rainfall in the past time by means of the determined fluorescent intensity. The correlation diagram of the determined and calculated or hindcast rainfall shows a synchronous change from 1982 to 1997. The peak positions of the variant curve are usually related to the El’nino year. That means the drought and flood recycles are restrained to some extent by globally environmental changes. Therefore, the coral fluorescent intensity acts as a geochemical proxy for reconstructing the rainfall series in the past hundreds of years and predicting the drought\|flood variant tendency in the future time.
