Perovskite type lithium fast ion conductors of Li 3 x La 0.67- x Y y Ti 1-2 y Nb y O 3 system were prepared by solid state reaction. X Ray powder diffraction shows that a single phase ...Perovskite type lithium fast ion conductors of Li 3 x La 0.67- x Y y Ti 1-2 y Nb y O 3 system were prepared by solid state reaction. X Ray powder diffraction shows that a single phase perovskite solid solution with orthorhombic structure forms in the ranges of x =0.10, y <0.075. Over this composition range the another phase, Y 2O 3 hexagonal phase is found. AC impedance measurements indicate that the bulk conductivities and the total conductivities are of the order of 10 -4 S·cm -1 and 10 -5 S·cm -1 at 25 ℃ respectively. The compositions have low bulk activation energies of about 20 kJ·mol -1 and total activation energies of about 40 kJ·mol -1 in the temperature range of 298～523 K, respectively.展开更多
A new oxide ion conductor, La3GaMo2O12, with a bulk conductivity of 2.7× 10^- 2 S·cm ^-1 at 800 ℃ in air atmosphere was prepared by the traditional solid-state reaction. The room temperature X-ray diffracti...A new oxide ion conductor, La3GaMo2O12, with a bulk conductivity of 2.7× 10^- 2 S·cm ^-1 at 800 ℃ in air atmosphere was prepared by the traditional solid-state reaction. The room temperature X-ray diffraction data could be indexed on a monoclinic cell with lattice parameters of a=0.5602（2） nm, b=0.3224（1） nm, c= 1.5741（1） nm, β= 102.555（0）°, V=0.2775（2） nm^3 and space group Pc（7）. Ac impedance measurements in various atmospheres further support that it is an oxide ion conductor. This material was stable in various atmospheres with oxygen partial pressure p（O2） ranging from 1.0× 10^5 to 1.0× 10^-7 Pa at 800 ℃. A reversible polymorphic phase transition occurred at elevated temperatures as confirmed by the differential thermal analysis and dilatometric measurement.展开更多
Perovskite type lithium fast ion conductors of Li 3 x La 0.67- x In y Ti 1-2 y P y O 3 system were prepared by solid state reaction. X ray powder diffraction shows that perovskite solid...Perovskite type lithium fast ion conductors of Li 3 x La 0.67- x In y Ti 1-2 y P y O 3 system were prepared by solid state reaction. X ray powder diffraction shows that perovskite solid solution forms in the ranges of x =0.10～0.12, y ≤0.2. AC impedance measurements indicate that the bulk conductivities and the total conductivities are of 1×10 -4 and 1× 10 -5 S·cm -1 at 25 ℃ respectively. The compositions have low bulk activation energies of 20 kJ·mol -1 in the temperature ranges of 298～523 K and total activation energies of 40 kJ·mol -1 in the temperature ranges of 298～623 K.展开更多
The dynamics of water and salt in soil were monitored in the 2010 and 2011 growing seasons of cotton to evaluate the salinity risk of soil under drip irrigation in arid environments for different management practices ...The dynamics of water and salt in soil were monitored in the 2010 and 2011 growing seasons of cotton to evaluate the salinity risk of soil under drip irrigation in arid environments for different management practices of drip system uniformity and irrigation amount. In the experiments, three Christiansen uniformity coefficients （CU） of approximately 65, 80, and 95% （referred to as low, medium, and high uniformity, respectively） and three irrigation amounts of 50, 75, and 100% of full irrigation were used. The distribution of the soil water content and bulk electrical conductivity （ECb） was monitored continuously with approximately equally spaced frequency domain reflectometry （FDR） sensors located along a dripline. Gravimetric samples of soil were collected regularly to determine the distribution of soil salinity. A great fluctuation in CU of water content and ECb at 60 cm depth was observed for the low uniformity treatment during the irrigation season, while a relatively stable variation pattern was observed for the high uniformity treatment. The ECb CU was substantially lower than the water content CU and its value was greatly related to the water content CU and the initial ECb CU. The spatial variation of seasonal mean soil water content and seasonal mean soil bulk electrical conductivity showed a high dependence on the variation pattern of emitter discharge rate along a dripline for the low and medium uniformity treatments. A greater irrigation amount produced a significantly lower soil salinity at the end of the irrigation season, while the influence of the system uniformity on the soil salinity was insignificant at a probability level of 0.1. In arid regions, the determination of the target drip irrigation system uniformity should consider the potential salinity risk of soil caused by nonuniform water application as the influence of the system uniformity on the distribution of the soil salinity was progressively strengthened during the growing season of crop.展开更多
文摘Perovskite type lithium fast ion conductors of Li 3 x La 0.67- x Y y Ti 1-2 y Nb y O 3 system were prepared by solid state reaction. X Ray powder diffraction shows that a single phase perovskite solid solution with orthorhombic structure forms in the ranges of x =0.10, y <0.075. Over this composition range the another phase, Y 2O 3 hexagonal phase is found. AC impedance measurements indicate that the bulk conductivities and the total conductivities are of the order of 10 -4 S·cm -1 and 10 -5 S·cm -1 at 25 ℃ respectively. The compositions have low bulk activation energies of about 20 kJ·mol -1 and total activation energies of about 40 kJ·mol -1 in the temperature range of 298～523 K, respectively.
基金Project supported by the National Natural Science Foundation of China（Nos. 20331030, 20471058）.
文摘A new oxide ion conductor, La3GaMo2O12, with a bulk conductivity of 2.7× 10^- 2 S·cm ^-1 at 800 ℃ in air atmosphere was prepared by the traditional solid-state reaction. The room temperature X-ray diffraction data could be indexed on a monoclinic cell with lattice parameters of a=0.5602（2） nm, b=0.3224（1） nm, c= 1.5741（1） nm, β= 102.555（0）°, V=0.2775（2） nm^3 and space group Pc（7）. Ac impedance measurements in various atmospheres further support that it is an oxide ion conductor. This material was stable in various atmospheres with oxygen partial pressure p（O2） ranging from 1.0× 10^5 to 1.0× 10^-7 Pa at 800 ℃. A reversible polymorphic phase transition occurred at elevated temperatures as confirmed by the differential thermal analysis and dilatometric measurement.
文摘Perovskite type lithium fast ion conductors of Li 3 x La 0.67- x In y Ti 1-2 y P y O 3 system were prepared by solid state reaction. X ray powder diffraction shows that perovskite solid solution forms in the ranges of x =0.10～0.12, y ≤0.2. AC impedance measurements indicate that the bulk conductivities and the total conductivities are of 1×10 -4 and 1× 10 -5 S·cm -1 at 25 ℃ respectively. The compositions have low bulk activation energies of 20 kJ·mol -1 in the temperature ranges of 298～523 K and total activation energies of 40 kJ·mol -1 in the temperature ranges of 298～623 K.
基金Ministry of Science&Technology of China:Sino-Italy International Cooperation on Innovation(2016YFE0104000)International Cooperation and Exchanges(NSFC,51561145007)National Energy Novel Materials Center(NENMC-Ⅱ-1705)
基金supported by the National Natural Science Foundation of China (50979115)
文摘The dynamics of water and salt in soil were monitored in the 2010 and 2011 growing seasons of cotton to evaluate the salinity risk of soil under drip irrigation in arid environments for different management practices of drip system uniformity and irrigation amount. In the experiments, three Christiansen uniformity coefficients （CU） of approximately 65, 80, and 95% （referred to as low, medium, and high uniformity, respectively） and three irrigation amounts of 50, 75, and 100% of full irrigation were used. The distribution of the soil water content and bulk electrical conductivity （ECb） was monitored continuously with approximately equally spaced frequency domain reflectometry （FDR） sensors located along a dripline. Gravimetric samples of soil were collected regularly to determine the distribution of soil salinity. A great fluctuation in CU of water content and ECb at 60 cm depth was observed for the low uniformity treatment during the irrigation season, while a relatively stable variation pattern was observed for the high uniformity treatment. The ECb CU was substantially lower than the water content CU and its value was greatly related to the water content CU and the initial ECb CU. The spatial variation of seasonal mean soil water content and seasonal mean soil bulk electrical conductivity showed a high dependence on the variation pattern of emitter discharge rate along a dripline for the low and medium uniformity treatments. A greater irrigation amount produced a significantly lower soil salinity at the end of the irrigation season, while the influence of the system uniformity on the soil salinity was insignificant at a probability level of 0.1. In arid regions, the determination of the target drip irrigation system uniformity should consider the potential salinity risk of soil caused by nonuniform water application as the influence of the system uniformity on the distribution of the soil salinity was progressively strengthened during the growing season of crop.
