Abstract: A fastener which allows to distinguish a genuine fastener from a forged one. An identification yarn containing substance with different optical reactions to irradiation of visible light and to irradiation of infrared rays of a specific wavelength is disposed at a specified position in the tape which is a component of the fastener. As a result, discrimination between genuine and false fasteners can be done safely without damaging the human health.

Abstract: The present invention provides a non-aqueous electrolyte secondary cell including: a cathode containing a manganese oxide or a lithium-manganese composite oxide; an anode containing a lithium metal, a lithium alloy, or a material capable of doping/dedoping lithium; and an electrolyte containing at least two electrolyte salts, one of which is LiBF4 contained in the range from 0.005 mol/l to 0.3 mol/l. This enables to increase the cycle characteristic, preventing deterioration of the cell characteristic caused by a repeated use.

Abstract: A glass composition contains PbO of 67 to 74 weight %, SiO.sub.2 of 11 to 20 weight %, B.sub.2 O.sub.3 of 3 to 8 weight %, TeO.sub.2 of 3 9 weight %, Na.sub.2 O of 0 to 3 weight %, and ZrO.sub.2 of 1 weight % smaller (except 0). A magnetic head according to the present invention includes a gap forming material, a spacing filling material, a bonding material, or an insulating material for a magnetic head. The gap forming material, the spacing filling material, the bonding material, or the insulating material is made of a glass composition containing PbO of 67 to 74 weight %, SiO.sub.2 of 11 to 20 weight %, B.sub.2 O.sub.3 of 3 to 8 weight %, TeO.sub.2 of 3 to 9 weight %, Na.sub.2 O of 0 to 3 weight %, and ZrO.sub.2 of 1 weight % or smaller (except 0).

Abstract: A smoke suction duct of an electric furnace is constructed as a separate member from other exhaust duct portions and other devices and is supported to be rotatable about an axis of the duct. Further, the smoke suction duct is either alternately turned to right and left or continuously turned in one direction by a duct turning device. Since accumulating dust is raised to an upper portion of the smoke suction duct where an exhaust gas flow has a high velocity due to rotation of the smoke suction duct and is pushed toward a combustion tower by the exhaust gas flow, dust is advantageously prevented from accumulating on a bottom of the smoke suction duct.