The new Er3+, Ho3+ and Tm3+ doped gadolinium oxysulfide phosphors with the long afterglow emission were synthesized by solid-state reaction method. The synthesized phosphors were characterized by X-ray diffraction. Th...The new Er3+, Ho3+ and Tm3+ doped gadolinium oxysulfide phosphors with the long afterglow emission were synthesized by solid-state reaction method. The synthesized phosphors were characterized by X-ray diffraction. The excitation and photoluminescence spectra, afterglow spectra and afterglow decay curve were examined by fluorescence spectroscopy. The afterglow spectra of Gd2O2S∶Er3+, Mg, Ti showed typical transitions of Er3+ at 528 (2H11/2 → 4I15/2),548 (4S3/2 → 4I15/2) and 669 nm (4F9/2 → 4I15/2). In the afterglow spectra of Gd2O2S∶ Ho3+, Mg, Ti, typical transitions of Ho3+ at 546 nm (5S2 → 5I8), 651 and 661 nm (5F5 → 5I8) were observed. In Gd2O2S∶Tm3+, Mg, Ti, the afterglow emission at 800 nm (1G4 → 3H5) of Tm3+ was seen. The mechnism and model of afterglow energy transfer were proposed.展开更多
Nanoparticles of red long afterglow phosphor Sr3Al2O6: Eu2+ were prepared by microwave irradiation method at a power of 680 W and a processing time of 15 min. The phosphors nanoparticles were characterized by X-ray di...Nanoparticles of red long afterglow phosphor Sr3Al2O6: Eu2+ were prepared by microwave irradiation method at a power of 680 W and a processing time of 15 min. The phosphors nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fluorescence spectrophotometer techniques. The results reveal that the samples are composed of single Sr3Al2O6 phase. The resultant nanoparticles show small size (80?100 nm) and spherical shape. The excitation and emission spectra indicate that excitation broad band chiefly lies in visible range and the nanoparticles emit much strong light at 612 nm under around 473 nm excitation. And the long afterglow phosphorescence of Sr3Al2O6 doped with Eu2+ was observed in the dark with naked eye after the removal of the excitation light. The effect of Eu2+ doping concentrations of the samples on the emission intensity is studied systematically. Furthermore, the microwave method requires a very short heating-time and the energy consumption.展开更多
Objectives Partial hepatectomy induces a rapid transformation within the remnant liver, prompting a wave of hepatocyte mitosis which abates when the lost cell mass has been recovered. The mechanism of co-ordinated con...Objectives Partial hepatectomy induces a rapid transformation within the remnant liver, prompting a wave of hepatocyte mitosis which abates when the lost cell mass has been recovered. The mechanism of co-ordinated control of metabolism and maintenance of function during this period of dynamic change is incompletely understood. Furthermore, the biochemical basis of growth regulation in the regenerating liver has not been well defined. We have studied human liver regeneration using in vivo 31-phosphorus magnetic resonance spectroscopy (31 P MRS). This non-invasive technique allows assay of high-energy phosphate compounds and also of phospholipid metabolites thought to be involved in cellular renewal processes.Methods Five patients undergoing liver resection were studied. Hepatic metabolism was evaluated using 31P MRS before surgery and on postoperative days 2,4,6 and 14. Estimation of liver volume by magnetic resonance imaging and blood sampling for biochemistry were performed at the same time points.Results We found that the regenerative response following loss of liver parenchyma produced a reversible decline in energy state which necessitated compensatory adjustments in liver synthetic and excretory (unctions. Volume regain was associated with alterations in phospholipid metabolism, which normalized when the hepatic growth spurt was completed.Conclusion These observations indicate that modulation of hepatocyte energy economy is necessary for the integrated recovery of liver cell mass and function. We propose that deficient hepatic energy production may explain the mechanism of liver failure after hepatectomy, and suggest that in vivo measurement of liver metabolism may provide a rational basis for the development and evaluation of hepatic support strategies.展开更多
The Eu 2+ and Dy 3+ codoped Sr 2MgSi 2O 7: Eu 2+ ,Dy 3+ blue emission long afterglow phosphor was synthesized and its photoluminescence properties were studied. It is known with the measurement method of X ray diffrac...The Eu 2+ and Dy 3+ codoped Sr 2MgSi 2O 7: Eu 2+ ,Dy 3+ blue emission long afterglow phosphor was synthesized and its photoluminescence properties were studied. It is known with the measurement method of X ray diffraction pattern that the luminescent material is an akermanite crystal. It is shown with the decay curve that its afterglow properties are better than the traditional (Ca,Sr)S:Bi blue long afterglow phosphor. Its decay curve is in accordance with the calculated results of the formula lg I=A+B 1 ×lg t +B 2×(lg t ) 2. Ther moluminescence spectra identified the existence of long afterglow luminescence. The excitation and emission spectra and microstructure of the phosphor were also investigated in detail.展开更多
文摘The new Er3+, Ho3+ and Tm3+ doped gadolinium oxysulfide phosphors with the long afterglow emission were synthesized by solid-state reaction method. The synthesized phosphors were characterized by X-ray diffraction. The excitation and photoluminescence spectra, afterglow spectra and afterglow decay curve were examined by fluorescence spectroscopy. The afterglow spectra of Gd2O2S∶Er3+, Mg, Ti showed typical transitions of Er3+ at 528 (2H11/2 → 4I15/2),548 (4S3/2 → 4I15/2) and 669 nm (4F9/2 → 4I15/2). In the afterglow spectra of Gd2O2S∶ Ho3+, Mg, Ti, typical transitions of Ho3+ at 546 nm (5S2 → 5I8), 651 and 661 nm (5F5 → 5I8) were observed. In Gd2O2S∶Tm3+, Mg, Ti, the afterglow emission at 800 nm (1G4 → 3H5) of Tm3+ was seen. The mechnism and model of afterglow energy transfer were proposed.
基金Project (50072014) supported by the National Natural Science Foundation of China
文摘Nanoparticles of red long afterglow phosphor Sr3Al2O6: Eu2+ were prepared by microwave irradiation method at a power of 680 W and a processing time of 15 min. The phosphors nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fluorescence spectrophotometer techniques. The results reveal that the samples are composed of single Sr3Al2O6 phase. The resultant nanoparticles show small size (80?100 nm) and spherical shape. The excitation and emission spectra indicate that excitation broad band chiefly lies in visible range and the nanoparticles emit much strong light at 612 nm under around 473 nm excitation. And the long afterglow phosphorescence of Sr3Al2O6 doped with Eu2+ was observed in the dark with naked eye after the removal of the excitation light. The effect of Eu2+ doping concentrations of the samples on the emission intensity is studied systematically. Furthermore, the microwave method requires a very short heating-time and the energy consumption.
文摘Objectives Partial hepatectomy induces a rapid transformation within the remnant liver, prompting a wave of hepatocyte mitosis which abates when the lost cell mass has been recovered. The mechanism of co-ordinated control of metabolism and maintenance of function during this period of dynamic change is incompletely understood. Furthermore, the biochemical basis of growth regulation in the regenerating liver has not been well defined. We have studied human liver regeneration using in vivo 31-phosphorus magnetic resonance spectroscopy (31 P MRS). This non-invasive technique allows assay of high-energy phosphate compounds and also of phospholipid metabolites thought to be involved in cellular renewal processes.Methods Five patients undergoing liver resection were studied. Hepatic metabolism was evaluated using 31P MRS before surgery and on postoperative days 2,4,6 and 14. Estimation of liver volume by magnetic resonance imaging and blood sampling for biochemistry were performed at the same time points.Results We found that the regenerative response following loss of liver parenchyma produced a reversible decline in energy state which necessitated compensatory adjustments in liver synthetic and excretory (unctions. Volume regain was associated with alterations in phospholipid metabolism, which normalized when the hepatic growth spurt was completed.Conclusion These observations indicate that modulation of hepatocyte energy economy is necessary for the integrated recovery of liver cell mass and function. We propose that deficient hepatic energy production may explain the mechanism of liver failure after hepatectomy, and suggest that in vivo measurement of liver metabolism may provide a rational basis for the development and evaluation of hepatic support strategies.
文摘The Eu 2+ and Dy 3+ codoped Sr 2MgSi 2O 7: Eu 2+ ,Dy 3+ blue emission long afterglow phosphor was synthesized and its photoluminescence properties were studied. It is known with the measurement method of X ray diffraction pattern that the luminescent material is an akermanite crystal. It is shown with the decay curve that its afterglow properties are better than the traditional (Ca,Sr)S:Bi blue long afterglow phosphor. Its decay curve is in accordance with the calculated results of the formula lg I=A+B 1 ×lg t +B 2×(lg t ) 2. Ther moluminescence spectra identified the existence of long afterglow luminescence. The excitation and emission spectra and microstructure of the phosphor were also investigated in detail.
