Abstract: The present invention relates to a process for a production of fiber-reinforced plastic tubing on a cored bar. Therefore, according to the invention, a fiber-reinforced plastic intermediate material obtained by laminating plural fiber-reinforced plastic intermediate material layers one after another is put and sealed in a bag-like membrane material, an inside of the membrane material is depressurized and then the fiber-reinforced intermediate material is taken out of the bag-like membrane material and wound around the cored bar to mold the FRP tubing.

Abstract: The present invention relates to a process for a production of fiber-reinforced plastic tubing on a cored bar. Therefore, according to the invention, a fiber-reinforced plastic intermediate material obtained by laminating plural fiber-reinforced plastic intermediate material layers one after another is put and sealed in a bag-like membrane material, an inside of the membrane material is depressurized and then the fiber-reinforced intermediate material is taken out of the bag-like membrane material and wound around the cored bar to mold the FRP tubing.

Abstract: A projection screen is comprised of a sheet formed by a multiplicity of light-transmitting plastic strands which strands are arranged and welded in parallel with one another. The width W (mm) of the screen and the pitch p (mm) of the strands meet the following condition (1):0.03.ltoreq.p.ltoreq.W/1000 (1)The radius of curvature R.sub.1 (mm) of the strand at a first side of the screen is determined by the following condition (2)0.5.times.p.ltoreq.R.sub.1 .ltoreq.p (2)The radius of curvature R.sub.2 (mm) of the strand at a second side of the screen meets the following condition(3):R.sub.2 .ltoreq.R.sub.1 (3).