Pei Feng

Evaluation of Soil Corrosivity for Ground Grid of Substations in an Area by Factor Analysis

Soils in a depth corresponding to half length of the buried grouding grids are sampled from sites of 123 substations of a 110 kV transmission network in an area. Their physical and chemical properties(11 indexes) are measured, which then are analyzed and processed by using the method of factor analysis. The results show that soil corrosivity for substation ground grid in this area is mainly influenced by calcium and magnesium ions, pH value, chloride ion and water content. A comprehensive evaluation is made based on these five key corrosive factors. It follows that the soil corrosivity for substation ground grids in this area may be divided into four levels as: exceptionally strong(11 substations), strong(86 substations), relatively strong(14 substations) and middle(12 substations). Meanwhile, the corrosivity of all the soil samples are evaluated according to German Beckman standard method. The results of the two methods are in accord with each other, which indicates that factor analysis can be applied to evaluate the soil corrosivity for substation ground grid with a good reliablility.

Al 3+ 掺杂0.5Li 2 MnO 3 -0.5LiCo 1/3 Ni 1/3 Mn 1/3 O 2 正极材料的研究

采用聚合热解法制备了掺入3% Al 3+ 的富锂锰基Li[Li 0.2 Co 0.13 Ni 0.13 Mn 0.51 Al 0.03 ]O 2 材料, 经过X射线衍射(XRD)、扫描电镜(SEM)实验表明, 掺入3%Al 3+ 样品仍然保持层状结构, 没有观察到杂质相的存在。在2.0~4.8 V范围内进行恒流充放电测试表明, 掺Al 3+ 样品在30 mA/g的电流密度下, 首周充放电比容量可达349.1和303.8 mAh/g(首次库仑效率87%); 在100 mA/g的电流密度下, 100次循环后, 容量保持率为91.7%, 显示出高的循环稳定性。这些结果表明掺杂Al 3+ 能够在一定程度上提高富锂氧化物材料层状结构的稳定性, 为发展高容量和高稳定性正极材料提供一种新途径。采用聚合热解法制备了掺入3% Al 3+ 的富锂锰基Li[Li 0.2 Co 0.13 Ni 0.13 Mn 0.51 Al 0.03 ]O 2 材料, 经过X射线衍射(XRD)、扫描电镜(SEM)实验表明, 掺入3%Al 3+ 样品仍然保持层状结构, 没有观察到杂质相的存在。在2.0~4.8 V范围内进行恒流充放电测试表明, 掺Al 3+ 样品在30 mA/g的电流密度下, 首周充放电比容量可达349.1和303.8 mAh/g(首次库仑效率87%); 在100 mA/g的电流密度下, 100次循环后, 容量保持率为91.7%, 显示出高的循环稳定性。这些结果表明掺杂Al 3+ 能够在一定程度上提高富锂氧化物材料层状结构的稳定性, 为发展高容量和高稳定性正极材料提供一种新途径。