Abstract: Disclosed are a polyester hollow fiber with excellent sound absorption and a method of manufacturing the same. The polyester hollow fiber may have a hollow ratio of about 27% to 35% compared to the cross-sectional area, and the value of the following equation (1) may be about 1.5 or greater, and the hollow in the cross-section preferably may be a three-lobed type and preferably may correspond to the following equation (1). P 4 ? ? ? A ( 1 ) In the above equation (1), A is the cross-sectional area (?m2) of the fiber, and P is the length (?m) around the cross-section of the fiber.

Abstract: A pseudospark switch including an insulator which can withstand high temperature plasma and is arranged between both electrodes thereof, thereby being capable of preventing the electrodes from being damaged while allowing a large amount of charge to flow instantaneously. The high power pseudospark switch includes first and second hollow electrodes facing each other, the hollow electrodes being open at facing ends thereof and closed at opposite ends thereof, respectively, an inert gas inlet port provided at the closed end wall of the first hollow electrode, a vacuum pump connecting port provided at the closed end wall of the second hollow electrode, a first electrode arranged at the open end of the first hollow electrode, a second electrode arranged at the open end of the second hollow electrode in such a manner that it faces the first electrode, and an insulator interposed between the first and second electrodes.