The Lancang–Mekong River basin(LMRB) is under increasing threat from global warming. In this paper, the projection of future climate in the LMRB is explored by focusing on the temperature change and extreme temperatu...The Lancang–Mekong River basin(LMRB) is under increasing threat from global warming. In this paper, the projection of future climate in the LMRB is explored by focusing on the temperature change and extreme temperature events. First, the authors evaluate the bias of temperature simulated by the Weather Research and Forecasting model. Then, correction is made for the simulation by comparing with observation based on the non-parametric quantile mapping using robust empirical quantiles(RQUANT) method. Furthermore, using the corrected model results, the future climate projections of temperature and extreme temperature events in this basin during 2016–35, 2046–65, and 2080–99 are analyzed. The study shows that RQUANT can effectively reduce the bias of simulation results. After correction, the simulation can capture the spatial features and trends of mean temperature over the LMRB, as well as the extreme temperature events. Besides, it can reproduce the spatial and temporal distributions of the major modes. In the future, the temperature will keep increasing, and the warming in the southern basin will be more intense in the wet season than the dry season. The number of extreme high-temperature days exhibits an increasing trend, while the number of extreme low-temperature days shows a decreasing trend. Based on empirical orthogonal function analysis, the dominant feature of temperature over this basin shows a consistent change. The second mode shows a seesaw pattern.展开更多
The influence of sintering temperature, carbon content and dispersive agent in bail-milling was investigated on the properties of LiFePO4/C prepared using Fe2O3, NH4H2PO4, Li2CO3 and glucose via solid state reaction. ...The influence of sintering temperature, carbon content and dispersive agent in bail-milling was investigated on the properties of LiFePO4/C prepared using Fe2O3, NH4H2PO4, Li2CO3 and glucose via solid state reaction. X-ray powder diffraction, scanning electron microscopy and charge-discharge test were applied to the characterization of the LiFePO4/C samples synthesized under different conditions. Sintering temperature affects the crystallite/ particle size and degree ofcrystallinity of LiFePO4, formation of Fe2P and maintenance of carbon in LiFePO4/C. Car- bon maintenance is favored by low sintering temperature, and 700 ℃ is optimum for synthesis of LiFePO4/C with superior electrochemical performance. A higher carbon content in the range of 4.48%-11.03% results in a better rate capability for LiFePO4/C. The dispersive agent used in ball-milling impacts the existent state of carbon in the final product which subsequently determines its charge-discharge behavior. The sample prepared at 700 ℃ by using acetone as the dispersive agent in ball-milling exhibits an excellent rate capability and capacity retention without any fade at 0.1 C, 1C and 2C, with corresponding average discharge capacities of 153.8, 128.3 and 121.0 mA·h·g-1. rest2ectivelv, in the first 50 cvcles.展开更多
A cobalt-free perovskite-type Ba0.5Sr0.5A10.1Fe0.9O3-δ （BSAF） chemically studied as solid oxide fuel cell （SOFC） cathode. The ductivity, and electrode polarizations in symmetrical cell based is developed and elec...A cobalt-free perovskite-type Ba0.5Sr0.5A10.1Fe0.9O3-δ （BSAF） chemically studied as solid oxide fuel cell （SOFC） cathode. The ductivity, and electrode polarizations in symmetrical cell based is developed and electro- structures, electrical con- on mixed ion conducting electrolyte were investigated, respectively. The temperature dependence of conductivity of BSAF in air shows a typical semiconductor behavior with positive temperature coefficient up to 450℃ where the conductivity reaches 14.0 S/cm while above this temperature the negative temperature coefficient dominates the total conductivity. Electrochemical charac- terizations show desirable polarization resistance of BSAF cathode in a symmetric cell based on mixed ion conducting electrolyte at 650-700℃, A single SOFC with BSAF cathode shows OCV of 1.0 V and maximum output of 420 mW/cm2 at 700 ℃ with humidified hydrogen fuel and static air oxidant.展开更多
基金This work was supported by the External Cooperation Program of Bureau of International Co-operation,Chinese Academy of Sciences[grant number GJHZ1729]the Key Program of the Natural Science Foundation of Yunnan Province of China[grant number 2016FA041].
文摘The Lancang–Mekong River basin(LMRB) is under increasing threat from global warming. In this paper, the projection of future climate in the LMRB is explored by focusing on the temperature change and extreme temperature events. First, the authors evaluate the bias of temperature simulated by the Weather Research and Forecasting model. Then, correction is made for the simulation by comparing with observation based on the non-parametric quantile mapping using robust empirical quantiles(RQUANT) method. Furthermore, using the corrected model results, the future climate projections of temperature and extreme temperature events in this basin during 2016–35, 2046–65, and 2080–99 are analyzed. The study shows that RQUANT can effectively reduce the bias of simulation results. After correction, the simulation can capture the spatial features and trends of mean temperature over the LMRB, as well as the extreme temperature events. Besides, it can reproduce the spatial and temporal distributions of the major modes. In the future, the temperature will keep increasing, and the warming in the southern basin will be more intense in the wet season than the dry season. The number of extreme high-temperature days exhibits an increasing trend, while the number of extreme low-temperature days shows a decreasing trend. Based on empirical orthogonal function analysis, the dominant feature of temperature over this basin shows a consistent change. The second mode shows a seesaw pattern.
基金Supported by the Natural Science Foundation of Yunnan Province(2010ZC051)the Analysis and Testing Foundation(20140439)the Starting Research Fund from Kunming University of Science and Technology(14118245)
文摘The influence of sintering temperature, carbon content and dispersive agent in bail-milling was investigated on the properties of LiFePO4/C prepared using Fe2O3, NH4H2PO4, Li2CO3 and glucose via solid state reaction. X-ray powder diffraction, scanning electron microscopy and charge-discharge test were applied to the characterization of the LiFePO4/C samples synthesized under different conditions. Sintering temperature affects the crystallite/ particle size and degree ofcrystallinity of LiFePO4, formation of Fe2P and maintenance of carbon in LiFePO4/C. Car- bon maintenance is favored by low sintering temperature, and 700 ℃ is optimum for synthesis of LiFePO4/C with superior electrochemical performance. A higher carbon content in the range of 4.48%-11.03% results in a better rate capability for LiFePO4/C. The dispersive agent used in ball-milling impacts the existent state of carbon in the final product which subsequently determines its charge-discharge behavior. The sample prepared at 700 ℃ by using acetone as the dispersive agent in ball-milling exhibits an excellent rate capability and capacity retention without any fade at 0.1 C, 1C and 2C, with corresponding average discharge capacities of 153.8, 128.3 and 121.0 mA·h·g-1. rest2ectivelv, in the first 50 cvcles.
文摘A cobalt-free perovskite-type Ba0.5Sr0.5A10.1Fe0.9O3-δ （BSAF） chemically studied as solid oxide fuel cell （SOFC） cathode. The ductivity, and electrode polarizations in symmetrical cell based is developed and electro- structures, electrical con- on mixed ion conducting electrolyte were investigated, respectively. The temperature dependence of conductivity of BSAF in air shows a typical semiconductor behavior with positive temperature coefficient up to 450℃ where the conductivity reaches 14.0 S/cm while above this temperature the negative temperature coefficient dominates the total conductivity. Electrochemical charac- terizations show desirable polarization resistance of BSAF cathode in a symmetric cell based on mixed ion conducting electrolyte at 650-700℃, A single SOFC with BSAF cathode shows OCV of 1.0 V and maximum output of 420 mW/cm2 at 700 ℃ with humidified hydrogen fuel and static air oxidant.
