Fabrication of Gd2O2S：Pr scintillation ceramics by 2Gd2O3.（Gd,Pr）2（SO4）3.mH2O precursor was made Gd2O3, Pr6O11 and H2SO4 as the starting materials pressureless reaction sintering was investigated. The by hydrothe...Fabrication of Gd2O2S：Pr scintillation ceramics by 2Gd2O3.（Gd,Pr）2（SO4）3.mH2O precursor was made Gd2O3, Pr6O11 and H2SO4 as the starting materials pressureless reaction sintering was investigated. The by hydrothermal reaction using commercially available Then single phase Gd2O2SO4：Pr powder was obtained by calcining the precursor at 750℃ for 2 h. The Gd2O2SO4：Pr powder compacts can be sintered to single phase Gd2O2S：Pr ceramics with a relative density of 99% and mean grain size of 30um at 1750℃ for 2 h in flowing hydrogen atmosphere. Densification and microstructural development of the Gd2O2S：Pr ceramics were examined. Luminescence spectra of the Gd2O2S：Pr ceramic under 309 nm UV excitation and X-ray excitation show a green emission at 511 nm as the most prominent peak, which corresponds to the ^3p0-3H4 transition of Pr^3＋ ions.展开更多
A BaF2 time differential perturbed angular distribution spectrometer has been established at the HI-13 tandem accelerator in CIAE. The time resolution of the spectrometer is 195 ps and the nonlinearity is less than 2 ...A BaF2 time differential perturbed angular distribution spectrometer has been established at the HI-13 tandem accelerator in CIAE. The time resolution of the spectrometer is 195 ps and the nonlinearity is less than 2 %. The spectrometer works very stably and no time drift is found over a period of experimelltal ruffs. This spectrometer has been successfully used in the g-factor measurement of 43 Sc (19/2-,3.1232 MeV).展开更多
The 2 nd Equatorial Plasma Bubble(EPB)workshop,funded by the Institute of Geology and Geophysics,Chinese Academy of Sciences,and the National Natural Science Foundation of China,took place in Beijing,China during Sept...The 2 nd Equatorial Plasma Bubble(EPB)workshop,funded by the Institute of Geology and Geophysics,Chinese Academy of Sciences,and the National Natural Science Foundation of China,took place in Beijing,China during September 13–15,2019.The EPB workshop belongs to a conference series that began in 2016 in Nagoya,Japan at the Institute for Space-Earth Environmental Research,Nagoya University,resulting in a special issue of Progress in Earth and Planetary Science that focused on EPBs.The main goal of the series is to organize in-depth discussion by scientists working on ionospheric irregularities,and solve the scientific challenges in EPB and ionospheric scintillation forecasting.The 2 nd EPB workshop gathered almost 60 scientists from seven countries.A total of 20 invited and contributing papers focusing on ionospheric irregularities and scintillations were presented.Here we briefly comment on 10 papers included in this special issue.展开更多
The vacuum ultraviolet (VUV) spectroscopic properties of praseodymium (Pr3+, 1at%) doped LaF3 nanocrystals/glass at room temperature and 20 K are reported. Two types of Pr3+ ions, those in LaF3 nanocrystals and those ...The vacuum ultraviolet (VUV) spectroscopic properties of praseodymium (Pr3+, 1at%) doped LaF3 nanocrystals/glass at room temperature and 20 K are reported. Two types of Pr3+ ions, those in LaF3 nanocrystals and those in the glass host, were excited to 4f 5d band by VUV using synchrotron radiation as an excitation source, and emissions of 1S0 → 1D2 (336 nm), 1S0 → 1I6 (397 nm ) of Pr3+ in the nanocrystals and emissions of 4f 5d → 3HJ, 3FJ of Pr3+ in the glass appeared at the same time. But unlike in the bulk sample crystals, emission of 3P0 → 3HJ, 3FJ as the second step of the quantum splitting (QS) of Pr3+ in the LaF3 nanocrystals was not observed at room temperature, which could be explained that Pr3+ ions in the glass absorbed the energy of 3P0 → 3H4 of Pr3+ in the nanocrystals. Two types of excitation spectra monitoring different emissions were also measured, so it could be observed that the lowest energy of 4f 5d band of Pr3+ in the nanocrystals was about 53 500 cm-1 (186 nm) and in the glass about 33 800 cm-1(295 nm), respectively. These emission and excitation spectra were contrasted to those of bulk sample crystals LaF3∶Pr3+.展开更多
基金supported by the National Natural Sci-ence Foundation of China (Grant. No. 50672014)the National Science Fund for Distinguished Young Scholars,China (Grant No. 50425413)
文摘Fabrication of Gd2O2S：Pr scintillation ceramics by 2Gd2O3.（Gd,Pr）2（SO4）3.mH2O precursor was made Gd2O3, Pr6O11 and H2SO4 as the starting materials pressureless reaction sintering was investigated. The by hydrothermal reaction using commercially available Then single phase Gd2O2SO4：Pr powder was obtained by calcining the precursor at 750℃ for 2 h. The Gd2O2SO4：Pr powder compacts can be sintered to single phase Gd2O2S：Pr ceramics with a relative density of 99% and mean grain size of 30um at 1750℃ for 2 h in flowing hydrogen atmosphere. Densification and microstructural development of the Gd2O2S：Pr ceramics were examined. Luminescence spectra of the Gd2O2S：Pr ceramic under 309 nm UV excitation and X-ray excitation show a green emission at 511 nm as the most prominent peak, which corresponds to the ^3p0-3H4 transition of Pr^3＋ ions.
文摘A BaF2 time differential perturbed angular distribution spectrometer has been established at the HI-13 tandem accelerator in CIAE. The time resolution of the spectrometer is 195 ps and the nonlinearity is less than 2 %. The spectrometer works very stably and no time drift is found over a period of experimelltal ruffs. This spectrometer has been successfully used in the g-factor measurement of 43 Sc (19/2-,3.1232 MeV).
基金the support from National Natural Science Foundation of China(42020104002)。
文摘The 2 nd Equatorial Plasma Bubble(EPB)workshop,funded by the Institute of Geology and Geophysics,Chinese Academy of Sciences,and the National Natural Science Foundation of China,took place in Beijing,China during September 13–15,2019.The EPB workshop belongs to a conference series that began in 2016 in Nagoya,Japan at the Institute for Space-Earth Environmental Research,Nagoya University,resulting in a special issue of Progress in Earth and Planetary Science that focused on EPBs.The main goal of the series is to organize in-depth discussion by scientists working on ionospheric irregularities,and solve the scientific challenges in EPB and ionospheric scintillation forecasting.The 2 nd EPB workshop gathered almost 60 scientists from seven countries.A total of 20 invited and contributing papers focusing on ionospheric irregularities and scintillations were presented.Here we briefly comment on 10 papers included in this special issue.
文摘The vacuum ultraviolet (VUV) spectroscopic properties of praseodymium (Pr3+, 1at%) doped LaF3 nanocrystals/glass at room temperature and 20 K are reported. Two types of Pr3+ ions, those in LaF3 nanocrystals and those in the glass host, were excited to 4f 5d band by VUV using synchrotron radiation as an excitation source, and emissions of 1S0 → 1D2 (336 nm), 1S0 → 1I6 (397 nm ) of Pr3+ in the nanocrystals and emissions of 4f 5d → 3HJ, 3FJ of Pr3+ in the glass appeared at the same time. But unlike in the bulk sample crystals, emission of 3P0 → 3HJ, 3FJ as the second step of the quantum splitting (QS) of Pr3+ in the LaF3 nanocrystals was not observed at room temperature, which could be explained that Pr3+ ions in the glass absorbed the energy of 3P0 → 3H4 of Pr3+ in the nanocrystals. Two types of excitation spectra monitoring different emissions were also measured, so it could be observed that the lowest energy of 4f 5d band of Pr3+ in the nanocrystals was about 53 500 cm-1 (186 nm) and in the glass about 33 800 cm-1(295 nm), respectively. These emission and excitation spectra were contrasted to those of bulk sample crystals LaF3∶Pr3+.
