Abstract: A head slider that includes a slider body having a air bearing surface, a magnetic head provided on the slider body, and a lubricant layer disposed on the air bearing surface, the lubricant layer being composed of a fluorocarbon resin.

Abstract: A position of a mobile communication terminal in an environment where the terminal cannot communicate with a GPS is defined more narrowly than a sector area of a base station in which the mobile communication terminal is located so that the position of the mobile communication terminal can be estimated more accurately. Even if a mobile communication terminal is in an environment where the terminal cannot communicate with a GPS, the latitude and longitude of the center of a sector of the wireless base station in which the mobile communication terminal is located is obtained according to a predetermined calculation by a base station database device, and the obtained latitude and longitude is sent back as an estimated latitude and longitude of the mobile communication terminal to the mobile communication terminal via the wireless base station.

Abstract: A position determination system includes a mobile terminal configured to receive GPS information from a GPS; a base station device configured to measure a round trip time (RTT) from the mobile terminal; a base-station position table unit configured to store position information on the base station device; a cable-length table unit configured to store a cable length between the base station device and an antenna assembly provided to the base station device, the antenna assembly communicates with the mobile terminal; and a position determination device configured to determine the position of the mobile terminal on the basis of the round trip time measured by the base station device, the cable length obtained from the cable-length table unit, the position information on the base station obtained from the base-station position table unit, and the GPS information received from the mobile terminal.