Abstract: A method of preparing polylactic acid (PLA) microsphere and polylactic-co-glycolic acid (PLGA) microsphere is provided, including the following steps. A first solution is provided, including polylactic acid or polylactic-co-glycolic acid and an organic solvent. A second solution is provided, including polyvinyl alcohol, sodium carboxymethyl cellulose and an aqueous solution. The first solution is added to the second solution and, at the same time, the second solution is agitated until polylactic acid is solidified to form a plurality of polylactic acid microspheres, or until polylactic-co-glycolic acid is solidified to form a plurality of polylactic-co-glycolic acid microspheres. The polylactic acid microspheres or polylactic-co-glycolic acid microspheres are collected.

Abstract: A VOD refining method for fast-cut stainless steel containing sulphur includes a step of VOD refining process, another step of reduction and residue producing and ferrous sulphide adding process, another step of micro-adjusting control process, and a last step of taking out the steel. The feature is to add 0.001 wt %-0.01 wt % CaO and 0.001 wt %-0.005 wt % MgO in the steel liquid during the micro-adjusting control process, in order to elevate sulphur absorption and enhance the aggregate sulphur recycling percentage to more than 85%.