Abstract: A bass reflex type speaker apparatus comprises a speaker box having an opening portion on a front surface, a speaker unit (1) mounted within the speaker box in conformity with the opening portion, and a tubular duct (7) that externally radiates sound from a rear surface of the speaker unit (1) disposed within the speaker box through phase inversion. The duct (7) has on the same plane one or a plurality of bent portions bent in substantially dogleg form and linear portions extending at both ends of the bent portion, the duct being disposed in parallel with the front surface of the speaker box. At least the longest linear portion of the linear portions is disposed tilted relative to wall surfaces except for the front and rear surfaces of the speaker box. It is thus possible to reduce the size, namely height, width and depth, of the speaker box incorporating the duct.

Abstract: A bass reflex type speaker apparatus comprises a speaker box having an opening portion on a front surface, a speaker unit (1) mounted within the speaker box in conformity with the opening portion, and a tubular duct (7) that externally radiates sound from a rear surface of the speaker unit (1) disposed within the speaker box through phase inversion. The duct (7) has on the same plane one or a plurality of bent portions bent in substantially dogleg form and linear portions extending at both ends of the bent portion, the duct being disposed in parallel with the front surface of the speaker box. At least the longest linear portion of the linear portions is disposed tilted relative to wall surfaces except for the front and rear surfaces of the speaker box. It is thus possible to reduce the size, namely height, width and depth, of the speaker box incorporating the duct.

Abstract: Smoke and nitrogen oxide in exhaust gases of diesel engines are reduced by burning a diesel fuel composition having a major portion of diesel fuel and 0.1 to 40 vol. % of a carbonic acid diester of the formula: in which R represents a lower hydrocarbon group having 1 to 6 carbon atoms, in a diesel engine by injecting the diesel fuel composition into a crank case at an injection timing of 17 to 2° CA, preferably, 14 to 8° CA, in terms of BTDC. EGR (exhaust gas recirculation system) is advantageously employable.

Abstract: In an IC card of this invention, a plurality of password numbers are previously stored and data can be read out from the IC card and written into the IC card when any one of the plurality of password numbers is input. Further, data readout and write-in with respect to the IC card are partially limited according to the input password number.

Abstract: A telephone exchange comprises a plurality of central office trunk circuits, a plurality of line circuits, a plurality of switching circuits coupled to transmission paths of the trunk and line circuits, a plurality of switching circuits coupled to the reception paths of the trunk and line circuits, a variable attenuator having one end coupled commonly to the switching circuits that are coupled to the transmission path, a conference circuit coupled to the variable attenuator and the switching circuits that are coupled to the reception paths, a control circuit which controls both groups of switching circuits and the variable attenuator in time-sharing fashion thereby to provide speech paths in time-sharing fashion between selected ones of the central office trunk circuits and line circuits and which controls in time-sharing fashion the attenuation factor of the variable attenuator for each speech path established.