In China, the proven reserves of natural gas is 3.86 trillion cubic meters (rcm). This figure will quite possibly increase at a high speed in the future. At pre
Four perovskite-type complex oxides (LaNiO3, La2NiO4, LaCoO3 and La2CoO4) were suc-cessfully prepared using two sol-gel methods, the Pechini method (PC) and the