High electron mobility transistors including a cavity below a drain and methods of manufacturing HEMTS including removing a portion of a substrate below a drain. After authentication information has been input on the displayed screen, a user corresponding to the authentication information and the plurality of image forming devices are associated with each other and managed by the service providing device. The moveable element includes a perpendicular portion oriented substantially perpendicular to a plane of the substrate. A magnetic-circuit arrangement is disposed on the measuring tube for producing and guiding a magnetic field which induces an electric field in the flowing fluid. Various methods of analyzing a biomolecule are also provided herein. The litters are made by producing the absorbent particles using conventional means and combining the absorbent particles with one or more filler particles that impart the desired characteristic to the litters.