Pigment was extracted from pericarp of black rice variety Zixiangnuo. The effects of several factors, including pH, light, chemical reagents and foodstuff additives on the color, solubility and heat stability of the p...Pigment was extracted from pericarp of black rice variety Zixiangnuo. The effects of several factors, including pH, light, chemical reagents and foodstuff additives on the color, solubility and heat stability of the pigment were observed. The color of the pigment varied with different acid conditions. When the pH was below 3, a stronger absorption peak at 495nm was observed. If the pH was between 3 and 10, there was a platform in 400-495nm. No obvious absorption peak in visible light region was found when pH was above 10. As the pH increased, the color of the pigment changed, from deep red to light red until to yellowishbrown, e.g. pH 0-2, deep red; pH3-4, red pH5-6, quite red; pH9-10, faint red; pH11, faint brown yellow; pH12, light brown yellow; pH13, yellowish brown; pH14, deep yellowish brown. The change of color was reversible. The pigment was quite stable under nature light conditions. At pH 1, it was basically unchanged within 10 d under sunlight or within 60 d under indoor nature light. However,展开更多
Brownmillerite-type oxides Ba_2In_（2-x-y）Mn_xAl_yO_（5＋x）（0 ≤ x ≤ 0.6, 0 ≤ y ≤ 0.5） were prepared at 1300°C through solid-state reaction. X-ray diffraction（XRD） analysis showed that the structure symm...Brownmillerite-type oxides Ba_2In_（2-x-y）Mn_xAl_yO_（5＋x）（0 ≤ x ≤ 0.6, 0 ≤ y ≤ 0.5） were prepared at 1300°C through solid-state reaction. X-ray diffraction（XRD） analysis showed that the structure symmetry evolved from orthorhombic to cubic with increasing Mn and Al contents. When y was greater than 0.3, peaks associated with small amounts of BaAl_2O_4 and Ba_2InAlO_5 impurities were observed in the XRD patterns. When substituted with a small amount of Mn（x ≤ 0.3）, the Ba_2In_（2-x-y）Mn_xAl_yO_（5＋x） samples exhibited an intense turquoise color. The color changed to green and dark-green with increasing Mn concentration. UV–vis absorbance spectra revealed that the color changed only slightly upon Al doping. The valence state of Mn ions in Ba_2In_（2-x-y）Mn_xAl_yO_（5＋x） was confirmed to be ＋5 on the basis of X-ray photoelectron spectroscopic analysis. According to this analysis, the intense turquoise color of the Ba_2In_（2-x-y）Mn_xAl_yO_（5＋x） samples is rooted in the existence of Mn^（5＋）; thus, the introduction of Al does not affect the optical properties of the compounds.展开更多
Calcined kaolin/TiO2 composite particle material （CK/TCPM） was prepared with TiO2 coating on the surfaces of calcined kaolin particles by the mechano-chemical method. X-ray diffraction （XRD） and scanning electron ...Calcined kaolin/TiO2 composite particle material （CK/TCPM） was prepared with TiO2 coating on the surfaces of calcined kaolin particles by the mechano-chemical method. X-ray diffraction （XRD） and scanning electron microscope （SEM） were used to investigate the microstructures and morphologies, respectively. The mechanism of the mechano-chemical reaction between calcined kaolin and TiO2 was studied by infrared spectra （IR）. The results show that TiO2 coats evenly on the surfaces of calcined kaolin particles by Si-O-Ti and Al-O-Ti bonds on their interfaces. The hiding power and whiteness of CK/TCPM are 17.12 g/m^2 and 95.7%, respectively, presenting its similarity to TiO2 in pigment properties.展开更多
文摘Pigment was extracted from pericarp of black rice variety Zixiangnuo. The effects of several factors, including pH, light, chemical reagents and foodstuff additives on the color, solubility and heat stability of the pigment were observed. The color of the pigment varied with different acid conditions. When the pH was below 3, a stronger absorption peak at 495nm was observed. If the pH was between 3 and 10, there was a platform in 400-495nm. No obvious absorption peak in visible light region was found when pH was above 10. As the pH increased, the color of the pigment changed, from deep red to light red until to yellowishbrown, e.g. pH 0-2, deep red; pH3-4, red pH5-6, quite red; pH9-10, faint red; pH11, faint brown yellow; pH12, light brown yellow; pH13, yellowish brown; pH14, deep yellowish brown. The change of color was reversible. The pigment was quite stable under nature light conditions. At pH 1, it was basically unchanged within 10 d under sunlight or within 60 d under indoor nature light. However,
基金financially supported by the National Natural Science Foundation of China (No.51402016)the Fundamental Research Funds for the Central Universities (No.FRF-TP-15-008A2)
文摘Brownmillerite-type oxides Ba_2In_（2-x-y）Mn_xAl_yO_（5＋x）（0 ≤ x ≤ 0.6, 0 ≤ y ≤ 0.5） were prepared at 1300°C through solid-state reaction. X-ray diffraction（XRD） analysis showed that the structure symmetry evolved from orthorhombic to cubic with increasing Mn and Al contents. When y was greater than 0.3, peaks associated with small amounts of BaAl_2O_4 and Ba_2InAlO_5 impurities were observed in the XRD patterns. When substituted with a small amount of Mn（x ≤ 0.3）, the Ba_2In_（2-x-y）Mn_xAl_yO_（5＋x） samples exhibited an intense turquoise color. The color changed to green and dark-green with increasing Mn concentration. UV–vis absorbance spectra revealed that the color changed only slightly upon Al doping. The valence state of Mn ions in Ba_2In_（2-x-y）Mn_xAl_yO_（5＋x） was confirmed to be ＋5 on the basis of X-ray photoelectron spectroscopic analysis. According to this analysis, the intense turquoise color of the Ba_2In_（2-x-y）Mn_xAl_yO_（5＋x） samples is rooted in the existence of Mn^（5＋）; thus, the introduction of Al does not affect the optical properties of the compounds.
基金Funded by the National Key Technology R&D Program of China(No.2008BAE60B06)Beijing Municipal Science&Technology Commission (No.Z080003032208015)
文摘Calcined kaolin/TiO2 composite particle material （CK/TCPM） was prepared with TiO2 coating on the surfaces of calcined kaolin particles by the mechano-chemical method. X-ray diffraction （XRD） and scanning electron microscope （SEM） were used to investigate the microstructures and morphologies, respectively. The mechanism of the mechano-chemical reaction between calcined kaolin and TiO2 was studied by infrared spectra （IR）. The results show that TiO2 coats evenly on the surfaces of calcined kaolin particles by Si-O-Ti and Al-O-Ti bonds on their interfaces. The hiding power and whiteness of CK/TCPM are 17.12 g/m^2 and 95.7%, respectively, presenting its similarity to TiO2 in pigment properties.
