Abstract: A method for flattening a three-dimensional shoe upper template is provided. The method includes providing a three-dimensional last model, obtaining a three-dimensional grid model, obtaining a three-dimensional thickened grid model, obtaining a two-dimensional initial-value grid model, and obtaining a two-dimensional grid model with the smallest energy value. A system and a non-transitory computer-readable medium for performing the method are also provided. The method makes it possible to precisely flatten a three-dimensional last model with a non-developable surface and thereby convert the three-dimensional last model into a two-dimensional grid model.

Abstract: This invention relates to a method of polymerization of lactide or glycolide (GA) monomers and in particular to a method of polymerizing one type of the monomers or two types of the monomers using alkyl aluminum catalyst to proceed with bulk or solution polymerization to prepare biodegradable homopolymers or copolymers, and high-molecular-weight homopolymers of polylactide (PLA), polyglycolide (PGA), or copolymers of lactide/glycolide prepared thereof.