Abstract: To develop a dental magnetic attachment having stable adhesive properties and capable of being adhered and fixed in a position in an alveolar ridge side, which does not require one to perform sandblast processing during the use and does not form a space between a permanent magnet structure and a denture base even when it is used in an oral cavity over a long period of time. 80 to 100% of a surface of a cover as a shell of the permanent magnet structure of the dental magnetic attachment, except for a surface thereof coming contact with a keeper, is beforehand processed by a chemical or mechanical method so as to have a surface roughness such that a maximum roughness, Rmax is 5 to 15 &mgr;m and that a ten-point average roughness, Rz is 3 to 8 &mgr;m.

Abstract: To develop a dental magnetic attachment having stable adhesive properties and capable of being adhered and fixed in a position in an alveolar ridge side, which does not require one to perform sandblast processing during the use and does not form a space between a permanent magnet structure and a denture base even when it is used in an oral cavity over a long period of time. 80 to 100% of a surface of a cover as a shell of the permanent magnet structure of the dental magnetic attachment, except for a surface thereof coming contact with a keeper, is beforehand processed by a chemical or mechanical method so as to have a surface roughness such that a maximum roughness, Rmax is 5 to 15 &mgr;m and that a ten-point average roughness, Rz is 3 to 8 &mgr;m.

Abstract: A number of units of projectors of a rear projection type are assembled together, and one screen commonly used for the assembled screen units is attached to front portions of the screen units. Assemblies, each having the above construction, are assembled in longitudinal and lateral directions to form a picture, so that a margin in the middle of the screen can be eliminated or the number of margins can be significantly reduced.

Abstract: A mist sprayer including an air blower, a spray head having a spray opening at a front end thereof and attached to the air blower, and a mist liquid vessel attached to the spray head. The spray head comprises a vessel attachment section to which the vessel is attached, and a spray tube provided inside the front of the spray head. A liquid intake at one end of the spray tube is opened in the vessel attachment section and a nozzle thereof at other end is positioned near the outlet of the spray head. An air hole is opened in the vessel attachment section to let air inside the vessel.