The invention relates to a yellow light afterglow material and a preparation method thereof as well as an LED illuminating device using the same. The disclosed methods and apparatus receive an encoded signal including encoded video frames and determine if video represented by the encoded video frames is frozen or blacked out based on a comparison of sizes of the encoded frames. A sensor member is mounted in the end of the axle and radially spaced from the exciting element. Further, the expansion component can evaluate the input data at a server side. The seal region has a wall thickness and is merged in a surface portion of the two parts of the envelope so that the surface unevenness of the seal region is not greater than 0. Also disclosed is a method of portioning food product at a predetermined size.