TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: The preparation of europium hydroxide and erbium hydroxide is carried out by weighing 1 mmol europium(III) oxide or erbium(III) oxide, dissolving in excess sodium hydroxide solution, preparing white flocculent precipitate, continuously dripping until no generated deposition to the solution, dispensing turbid liquid in equal 50 mL centrifuge tube, rotating with a rotating speed of 4000 rpm for 5 minutes, taking out upper-layer clear liquid from centrifugal tube, adding deionized water, stirring for 2-3 times, taking upper layer clear liquid with a glass rod, dropping on a pH paper, washing until it is neutral, repeating the alkaline washing process, and removing supernatant liquid.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The acrylic europium or acrylic erbium is prepared by adding acrylic acid into a centrifugal tube, shaking, continuously stirring until the precipitate is completely dissolved, providing into an oil bath at 120 degrees C, magnetic stirring until the paste is processed into original solution, stopping heating, taking out, cooling, carrying out reverse washing in absolute ethyl alcohol, providing the washed liquid in a centrifugal tube, rotating with a rotating speed of 4000 rpm for 5 minutes, taking out upper clear liquid from centrifugal tube, removing supernatant liquid, washing for 2-3 times, and obtaining precipitate of acrylic europium or acrylic erbium.    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The copolymerization of vinyl acetate and acrylic europium is carried out by adding the prepared acrylic europium or acrylic erbium in 250 mL three-neck flask, dissolving in 70 mL ethanol at 65 degrees C, respectively adding 3 mL methanol solution, 7 g vinyl acetate and 0.02 g azo-bis-isobutyrynitrile for 0.5 hour, heating at 65-70 degrees C for 2 hours, then cooling to room temperature, removing ethanol, and drying. The ethylene-vinyl acetate/vinyl-acrylic acid-europium or ethylene-vinyl acetate/vinyl-acrylic acid-erbium film is prepared by adding 100 parts mass ethyl-vinyl acetate, and europium or erbium to 0.01-0.2 parts mass vinyl-acrylic acid-europium or vinyl-acrylic acid-erbium, milling by a internal mixer, mixing at 100 degrees C for 10 minutes, processing into a sheet by surface plating, providing into a mold with height of 0.15 mu m at 150 degrees C, pressing for 15 minutes, and cooling to 20-25 degrees C.