Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People＇s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, C...Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People＇s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, CO, NOx and CnHm of electrified railways, and analyzed their dynamic characteristics during the period of 1975 2007. The results show that during this period, the annual mean values of energy saving is 1.23×10^6 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 4.267×10^6 t, 20.5×10^3 t, 3.0×10^3 t, 9.6×10^3 t, 67.9×10^3 t, and 6.9×10^3 t per year, respectively. The annual average increasing rates of energy saving is 139×10^3 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 483×10^3 t, 2.3×10^3 t, 0.34×10^3 t, 1.1×10^3 t, 7.7 ×10^3 t and 0.78×10^3 t per year, respectively. The electrified railways have played an important role in decreasing the energy consumption and air pollutant emissions of China＇s railway system. The results of this study could provide some reference knowledge for future reductions of energy consumption and waste gas emission in China＇s railway transportation.展开更多
LiFePO4 cathode material is synthesized by a simple solid-state reaction method with FePO42H20 as iron source and citric acid as reductive agent and carbon source. This study examines the effects of different oxidatio...LiFePO4 cathode material is synthesized by a simple solid-state reaction method with FePO42H20 as iron source and citric acid as reductive agent and carbon source. This study examines the effects of different oxidation routes to prepare FePO4＂2H20 on the electrochemical performance of as-synthesized LiFePO4. Iron phosphate was prepared by two routes from FeSO4＇7H20. One is the formation of Fe3（PO4）2 precipitate in the first step and subsequent oxidation to FePO4 precipitate. The other is the oxidation of ferrous to ferric ion firstly, and then to form FePO4 precipitate directly. The results indicate that substantial differences in the structure and electrochemical properties of LiFePO4 depend on the behavior of FePO4. Iron phosphate obtained through one step precipitation has a smaller particle size and more uniform particle distribution, which is demonstrated to be more applicable as the iron source to synthesize LiFePO4/C. As-prepared LiFePO4/C shows an excellent rate capability and cycle performance. The initial discharge capacities of 160.6 mAh/g and 107 mAh/g are achieved at 0.1 C and 10 C, respectively. The good capacity retention of 97% after 300 cycles is maintained at the rate of 5 C.展开更多
A kind of closed-loop Hall effect sensor is designed and fabricated by considering several factors such as iron core material, Hall device, as well as selected integrated circuit. Through studying the effect of the ir...A kind of closed-loop Hall effect sensor is designed and fabricated by considering several factors such as iron core material, Hall device, as well as selected integrated circuit. Through studying the effect of the iron material and structures of current sensor, a kind of optimal Hall effect current sensor is found. The experimental results show that the presented closed-loop Hall effect current sensor achieves 1 mA/A sensitivity. And its lineafity and accuracy are 0.1% and 0.35% FS, respectively, at cur- rents ranging from 0 to 50 A.展开更多
基金supported by Climate Change Special Project of China Meteorological Administration(No CCSF2011-14)
文摘Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People＇s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, CO, NOx and CnHm of electrified railways, and analyzed their dynamic characteristics during the period of 1975 2007. The results show that during this period, the annual mean values of energy saving is 1.23×10^6 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 4.267×10^6 t, 20.5×10^3 t, 3.0×10^3 t, 9.6×10^3 t, 67.9×10^3 t, and 6.9×10^3 t per year, respectively. The annual average increasing rates of energy saving is 139×10^3 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 483×10^3 t, 2.3×10^3 t, 0.34×10^3 t, 1.1×10^3 t, 7.7 ×10^3 t and 0.78×10^3 t per year, respectively. The electrified railways have played an important role in decreasing the energy consumption and air pollutant emissions of China＇s railway system. The results of this study could provide some reference knowledge for future reductions of energy consumption and waste gas emission in China＇s railway transportation.
基金supported by a project issued by the National Key Technologies R&D Program of China (2009BAG19B00)National High Technology Research and Development Program of China (SS2012AA110301)
文摘LiFePO4 cathode material is synthesized by a simple solid-state reaction method with FePO42H20 as iron source and citric acid as reductive agent and carbon source. This study examines the effects of different oxidation routes to prepare FePO4＂2H20 on the electrochemical performance of as-synthesized LiFePO4. Iron phosphate was prepared by two routes from FeSO4＇7H20. One is the formation of Fe3（PO4）2 precipitate in the first step and subsequent oxidation to FePO4 precipitate. The other is the oxidation of ferrous to ferric ion firstly, and then to form FePO4 precipitate directly. The results indicate that substantial differences in the structure and electrochemical properties of LiFePO4 depend on the behavior of FePO4. Iron phosphate obtained through one step precipitation has a smaller particle size and more uniform particle distribution, which is demonstrated to be more applicable as the iron source to synthesize LiFePO4/C. As-prepared LiFePO4/C shows an excellent rate capability and cycle performance. The initial discharge capacities of 160.6 mAh/g and 107 mAh/g are achieved at 0.1 C and 10 C, respectively. The good capacity retention of 97% after 300 cycles is maintained at the rate of 5 C.
基金supported by the National Basic Research Program of China("973"Project)(Grant No.2011CB309504)the National Key Project of Semiconductor Equipment(02)(Grant No.2009ZX02037)
文摘A kind of closed-loop Hall effect sensor is designed and fabricated by considering several factors such as iron core material, Hall device, as well as selected integrated circuit. Through studying the effect of the iron material and structures of current sensor, a kind of optimal Hall effect current sensor is found. The experimental results show that the presented closed-loop Hall effect current sensor achieves 1 mA/A sensitivity. And its lineafity and accuracy are 0.1% and 0.35% FS, respectively, at cur- rents ranging from 0 to 50 A.
