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 rotating tee structure for golf is disclosed. The tee structure comprises a seat body, a rotating connector, a lifting ring, an elastic arm, a ball-holding seat and a pivotal rod, wherein the elastic arm is mounted on the body having a fixing leg and the rotating connector. One end of the elastic arm is disposed with the ball-holding seat to accommodate a golf ball. When the golf ball on the ball-holding seat is hit with a golf club, the elastic arm and the rotating connector absorb the impact force at the instance when the golf club strikes the ball.