A compact turbo-molecular pump having a high depressurizing capability. A shield may include a flap extending from the shield body for covering a portion of the component not already covered by the shield body. The tray includes at least one elevating bracket for maintaining a predetermined distance between the tray and the tray support. The resulting deformation field is globally smooth and guarantees one-to-one mapping between the images being registered. The method includes receiving multiple IP data packets on the IO ports at substantially the same time, and sending multiple data packets from the wireless device to the server, whereby the transmission rate between the wireless device and the server is increased. An image category identifier is entered and received.