BaBa1.03Ce0.8Tm0.2O3-aceramic with orthorhombic perovskite structure was prepared by conventional solid-state reaction. The conductivity and ionic transport number of BaBa1.03Ce0.8Tm0.2O3-a a were measured by ac imped...BaBa1.03Ce0.8Tm0.2O3-aceramic with orthorhombic perovskite structure was prepared by conventional solid-state reaction. The conductivity and ionic transport number of BaBa1.03Ce0.8Tm0.2O3-a a were measured by ac impedance spectroscopy and gas concentration cell methods in the temperature range of 500-900 ℃ in wet hydrogen and wet air. Using the ceramic as solid electrolyte and porous platinum as electrodes, the hydrogen-air fuel cell was constructed, and the cell performance was examined at 500-900℃. The results indicate that the specimen is a pure ionic conductor with the ionic transport number of 1 at 500-900 ℃ in wet hydrogen. In wet air, the specimen is a mixed conductor of proton, oxide ion and electron hole. The protonic transport numbers are 0.071-0.018, and the oxide ionic transport numbers are 0.273-0.365. The conductivities of Bal.03Ceo.sTmo.203 a under wet hydrogen, wet air or fuel cell atmosphere are higher than those of BaBa1.03Ce0.8Tm0.2O3-a a （RE=Y, Eu, Ho） reported previously by us. The fuel cell can work stably. At 900℃ the maximum power output density is 122.7 mWocm 2, which is higher than that of our previous cell using BaBa1.03Ce0.8Tm0.2O3-a（RE=Y, Eu, Ho） as electrolyte.展开更多
The GECAM series of satellites utilizes LaBr_(3)(Ce),LaBr_(3)(Ce,Sr),and NaI(Tl)crystals as sensitive materials for gamma-ray detectors(GRDs).To investigate the nonlinearity in the detection of low-energy gamma rays a...The GECAM series of satellites utilizes LaBr_(3)(Ce),LaBr_(3)(Ce,Sr),and NaI(Tl)crystals as sensitive materials for gamma-ray detectors(GRDs).To investigate the nonlinearity in the detection of low-energy gamma rays and address the errors in the calibration of the E-C relationship,comprehensive tests and comparative studies of the three aforementioned crystals were conducted using Compton electrons,radioactive sources,and mono-energetic X-rays.The nonlinearity test results of the Compton electrons and X-rays demonstrated substantial differences,with all three crystals presenting a higher nonlinearity for X/-rays than for Compton electrons.Despite the LaBr_(3)(Ce)and LaBr_(3)(Ce,Sr)crystals having higher absolute light yields,they exhibited a noticeable nonlinear decrease in the light yield,especially at energies below 400 keV.The NaI(Tl)crystal demonstrated an"excess"light output in the 6-200 keV range,reaching a maximum"excess"of 9.2%at 30 keV in the X-ray testing and up to 15.5%at 14 keV during Compton electron testing,indicating a significant advantage in the detection of low-energy gamma rays.Furthermore,we explored the underlying causes of the observed nonlinearity in these crystals.This study not only elucidates the detector responses of GECAM,but also initiates a comprehensive investigation of the nonlinearity of domestically produced lanthanum bromide and sodium iodide crystals.展开更多
基金Project supported by the National Natural Science Foundation of China （No. 20771079）, Qing Lan Project and the Natural Science Foundation of Education Department of Jiangsu Province （No. 07KJB 150126）.
文摘BaBa1.03Ce0.8Tm0.2O3-aceramic with orthorhombic perovskite structure was prepared by conventional solid-state reaction. The conductivity and ionic transport number of BaBa1.03Ce0.8Tm0.2O3-a a were measured by ac impedance spectroscopy and gas concentration cell methods in the temperature range of 500-900 ℃ in wet hydrogen and wet air. Using the ceramic as solid electrolyte and porous platinum as electrodes, the hydrogen-air fuel cell was constructed, and the cell performance was examined at 500-900℃. The results indicate that the specimen is a pure ionic conductor with the ionic transport number of 1 at 500-900 ℃ in wet hydrogen. In wet air, the specimen is a mixed conductor of proton, oxide ion and electron hole. The protonic transport numbers are 0.071-0.018, and the oxide ionic transport numbers are 0.273-0.365. The conductivities of Bal.03Ceo.sTmo.203 a under wet hydrogen, wet air or fuel cell atmosphere are higher than those of BaBa1.03Ce0.8Tm0.2O3-a a （RE=Y, Eu, Ho） reported previously by us. The fuel cell can work stably. At 900℃ the maximum power output density is 122.7 mWocm 2, which is higher than that of our previous cell using BaBa1.03Ce0.8Tm0.2O3-a（RE=Y, Eu, Ho） as electrolyte.
基金This work was supported by the National Key Research and Development Program(Nos.2022YFB3503600 and 2021YFA0718500)Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDA15360102)National Natural Science Foundation of China(Nos.12273042 and 12075258).
文摘The GECAM series of satellites utilizes LaBr_(3)(Ce),LaBr_(3)(Ce,Sr),and NaI(Tl)crystals as sensitive materials for gamma-ray detectors(GRDs).To investigate the nonlinearity in the detection of low-energy gamma rays and address the errors in the calibration of the E-C relationship,comprehensive tests and comparative studies of the three aforementioned crystals were conducted using Compton electrons,radioactive sources,and mono-energetic X-rays.The nonlinearity test results of the Compton electrons and X-rays demonstrated substantial differences,with all three crystals presenting a higher nonlinearity for X/-rays than for Compton electrons.Despite the LaBr_(3)(Ce)and LaBr_(3)(Ce,Sr)crystals having higher absolute light yields,they exhibited a noticeable nonlinear decrease in the light yield,especially at energies below 400 keV.The NaI(Tl)crystal demonstrated an"excess"light output in the 6-200 keV range,reaching a maximum"excess"of 9.2%at 30 keV in the X-ray testing and up to 15.5%at 14 keV during Compton electron testing,indicating a significant advantage in the detection of low-energy gamma rays.Furthermore,we explored the underlying causes of the observed nonlinearity in these crystals.This study not only elucidates the detector responses of GECAM,but also initiates a comprehensive investigation of the nonlinearity of domestically produced lanthanum bromide and sodium iodide crystals.
