Blue sapphires are treated with Be in oxidizing atmosphere to change the blue colour into yellow. Untreated and Be-treated samples are examined using laser ablation inductively coupled-plasma-mass spectrometry （LA-I...Blue sapphires are treated with Be in oxidizing atmosphere to change the blue colour into yellow. Untreated and Be-treated samples are examined using laser ablation inductively coupled-plasma-mass spectrometry （LA-ICP- MS）, electron spin resonance （ESR） and ultraviolet-visible （UV-vis） spectroscopy. The results show that the yellow colouration in Be-heated blue sapphires is not due to Be diffusion from the surface of sapphire. Be behaves as a sole catalyst in this process. We find that the charge transfer between the ferrous （Fe^2＋） and ferric （Fe^3＋） is the reason of the colour change. The above conclusions are confirmed by ESR measurements to determine the connections between the Fe3＋ ions before and after Be-treated heat treatments.展开更多
A method for quantitative/qualitative determination of cane sugar purity by ESR is devised. Relined sugar, plantation white sugar, soft brown sugar and raw sugar are used as samples in this work. The sucrose radical i...A method for quantitative/qualitative determination of cane sugar purity by ESR is devised. Relined sugar, plantation white sugar, soft brown sugar and raw sugar are used as samples in this work. The sucrose radical is produced by pulverization of sugar and it increases as the particle size decreases. Based on pulverization-induced sucrose radical, ESR study demonstrates the effects of sugar purity on characteristic of ESR spectrum. The relationship between the sucrose contents and peak area under the ESR spectrum is manifested. It is found that the peak area or sucrose radical concentration increases linearly with the increase of sucrose content. Using the linear regression method, the sucrose amount can be revealed. This approach is a promising fast and accurate method for sugar purity analysis.展开更多
The commercial TiO2 nanopowder and micropowder of anatase phase and rutile phase have been characterized by X-ray diffraction （XRD） and electron spin resonance （ESR） spectroscopy. XRD patterns and ESR spectra of n...The commercial TiO2 nanopowder and micropowder of anatase phase and rutile phase have been characterized by X-ray diffraction （XRD） and electron spin resonance （ESR） spectroscopy. XRD patterns and ESR spectra of nano-TiO2 in rutile and anatase phases exhibit broad peaks whereas both phases of micro-TiOz demonstrate very sharp peaks. Furthermore, the anatase phase of both particle sizes provide ESR peak at a magnetic field around 3568.25G, On the other hand, this peak is not established in the rutile phase of both particle sizes.展开更多
文摘Blue sapphires are treated with Be in oxidizing atmosphere to change the blue colour into yellow. Untreated and Be-treated samples are examined using laser ablation inductively coupled-plasma-mass spectrometry （LA-ICP- MS）, electron spin resonance （ESR） and ultraviolet-visible （UV-vis） spectroscopy. The results show that the yellow colouration in Be-heated blue sapphires is not due to Be diffusion from the surface of sapphire. Be behaves as a sole catalyst in this process. We find that the charge transfer between the ferrous （Fe^2＋） and ferric （Fe^3＋） is the reason of the colour change. The above conclusions are confirmed by ESR measurements to determine the connections between the Fe3＋ ions before and after Be-treated heat treatments.
文摘A method for quantitative/qualitative determination of cane sugar purity by ESR is devised. Relined sugar, plantation white sugar, soft brown sugar and raw sugar are used as samples in this work. The sucrose radical is produced by pulverization of sugar and it increases as the particle size decreases. Based on pulverization-induced sucrose radical, ESR study demonstrates the effects of sugar purity on characteristic of ESR spectrum. The relationship between the sucrose contents and peak area under the ESR spectrum is manifested. It is found that the peak area or sucrose radical concentration increases linearly with the increase of sucrose content. Using the linear regression method, the sucrose amount can be revealed. This approach is a promising fast and accurate method for sugar purity analysis.
基金supported by the Department of Physics,Faculty of Science,King Mongkut's University of Technology Thonburi
文摘The commercial TiO2 nanopowder and micropowder of anatase phase and rutile phase have been characterized by X-ray diffraction （XRD） and electron spin resonance （ESR） spectroscopy. XRD patterns and ESR spectra of nano-TiO2 in rutile and anatase phases exhibit broad peaks whereas both phases of micro-TiOz demonstrate very sharp peaks. Furthermore, the anatase phase of both particle sizes provide ESR peak at a magnetic field around 3568.25G, On the other hand, this peak is not established in the rutile phase of both particle sizes.
