A method for processing queries for a document of elements is provided. The housing includes an end wall turned away from a sieving unit and a peripheral wall formed with at least one chaff discharge opening. The intervals between adjacent injection holes are approximately equal to each other, while the diameters of the injection holes are equal to each other. The single fiber layer structure of nano fibers comprises a web of nano fibers formed by plural interweaved nano fibers. Performing the existing analysis repeatedly may be avoided, and the user may re-define the detection conditions in this manner.