Abstract: To provide a pulse tube refrigerator for enhancing refrigeration capacity. A pulse tube refrigerator includes a pressure-waveform generating device 1 for generating a pressure waveform of refrigerant gas, pulse tubes 14, 20 into which refrigerant gas with pressure waveforms flow, one of whose ends is adapted to a low-temperature end, and the other one of whose ends is adapted to a high-temperature end, cold accumulators 8, 10 for pre-cooling the refrigerant gas to be flowed into the pulse tubes 14, 20, a pressure-waveform phase controlling element having a buffer tank 23 communicating with the high-temperature end of the pulse tube 20, and controlling a pressure-waveform phase of the refrigerant gas for generating refrigeration at the low-temperature end of the pulse tube 20, and a vacuum heat-insulation bath 24 having a vacuum heat-insulation chamber 24w for accommodating the pulse tube 20. The buffer tank 23 is placed within the vacuum heat-insulation chamber 24w of the vacuum heat-insulation bath 24.

Abstract: A linear actuator, in which a plurality of electromagnets where coils are wound around magnetic materials are provided so as to face each other in a manner where the polarities N and S of the electromagnets alternate at the time of excitation, and magnetic poles of a plurality of permanent magnets that are aligned so as to form a movable member are placed in positions that face the plurality of magnetic poles, in which the permanent magnets extend beyond the portions where the magnetic poles of the electromagnets are provided so as to face and therefore effects are attained that a stable force of magnetic attraction in the direction of the stroke is obtained and peeling and cracking of the permanent magnet are prevented.