Abstract: A horn amplifier comprises a horn and at least one speaker member with at least one spherical sound source; wherein the horn has one throat portion and one voice port opened from the throat portion toward outside, the bottom surface of the inner side of the throat portion of the horn has an open, the spherical sound source of the speaker member connects with the open, the inner side of the throat portion has at least one S-type sound-guide board, the sound-guide board is made as a plurality of paths in order to let spherical sound waves from the spherical sound source of the speaker member enter into the paths, then the spherical sound waves are transformed into plane sound waves, the plane sound waves are delivered to outside through the inner structure of the horn.

Abstract: A horn amplifier comprises a horn and at least one speaker member with at least one spherical sound source; wherein the horn has one throat portion and one voice port opened from the throat portion toward outside, the bottom surface of the inner side of the throat portion of the horn has an open, the spherical sound source of the speaker member connects with the open, the inner side of the throat portion has at least one S-type sound-guide board, the sound-guide board is made as a plurality of paths in order to let spherical sound waves from the spherical sound source of the speaker member enter into the paths, then the spherical sound waves are transformed into plane sound waves, the plane sound waves are delivered to outside through the inner structure of the horn.

Abstract: Disclosed are a method for manufacturing a cell sheet, comprising culturing cells on a fibrin-coated surface of a substrate until the cells reach confluency, continuing the cultivation of the cells for a sufficient time period to cause the degradation of fibrin at the bottom of the cells, and detaching the cultured cells from the substrate surface in a sheet-like form to give a cell sheet; a substrate for cell sheet preparation, a surface of which is coated with fibrin; and a composition for use in coating with fibrin a surface of a substrate for cell sheet preparation, the composition comprising fibrinogen and thrombin. The invention enables to cell sheets to be manufactured by a simple manipulation using a substrate coated with a commercial, commonly available material of which safety has been confirmed.