TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The alkali is sodium carbonate or sodium bicarbonate.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The glycine ethyl ester hydrochloride, alkali, and alcohol solvent are stirred for 2-4 (preferably 2.5) hours at 65-70 (preferably 65-67) degrees C. The pH value is 8-10, preferably 9. The alcohol solvent is anhydrous ethanol. The mol ratio of glycine ethyl ester hydrochloride to sodium carbonate is 1:1 or 1:2. The dosage of the anhydrous ethanol is 5-10 (preferably) times of dosage of alkali. The method needs 3-5 times to add alkali to regulate the pH value to 9-9.5 after mixing the glycine ethyl ester hydrochloride and alkali. The (S)-4-halo-3-hydroxy-butanoate is dripped for 2 hours, and reacted for 25-28 hours at 65-70 degrees C. The crude product of (S)-4-hydroxy-2-oxo-1-pyrrolidine acetamide is prepared by reacting glycine ethyl ester hydrochloride with alkali and alcohol solvent, stirring for 2-4 hours at 65-70 degrees C and pH value of 8-10. The filtrate is cleaned with methanol or ethanol. The concentrate is dissolved into water. Extraction is done by adding 4 times of chloroform by weigh of the filtrate. After the aqueous phase concentration, the (S)-4-hydroxy-2-oxo-1-pyrrolidine acetamide is obtained by column chromatography separating. The reaction is done for 6-8 hours at 25-30 degrees C by adding concentrated ammonia water (28 mass%). The crude product is purified by using water and exchanging resin by using strongly acidic cation, and collecting, and exchanging resin of collected solution by using the strongly basic anion. When the pH value of the collected solution is neutral, the reaction can be stopped. Crystallization is performed. The dosage of the (S)-4-halo-3-hydroxy-butanoate is glycine ethyl ester hydrochloride:(S)-4-halo-3-hydroxy-butanoate is 1mol:1-1.5mol. The recrystallizing treatment takes ethanol to realize first recrystallizing treatment. The second recrystallization uses mixed solvent of methanol/acetone. The ratio of the water solution of crude product to water is 1g:1.4ml. The ratio of crude product to the strong basic anion exchange resin is 1g:13 ml. In the first recrystallizing treatment, the concentrated crude product to ethanol ratio is 1 g:4 ml. In the second recrystallizing treatment, the first recrystallized crude product to methanol ratio is 1 g:3 ml. The volume ratio of methanol and acetone in mixed solvent of methanol/acetone is 1:2. Preferred Component: The (S)-4-halo-3-hydroxy-butanoate is (S)-4-chloro-3-hydroxy-butanoate.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The strong acid cation exchange resin is 732 strong acid cation exchange resin. The strong basic anion exchange resin is 711 strong basic anion exchange resin.