Abstract: A lever type connector comprising: a first connector; a second connector which is fitted into the first connector; a lever which is rotatably mounted on the first connector; and a pin which projects from the second connector; the lever being formed with an engageable hole such that the pin is inserted into the engageable hole when the second connector is fitted into the first connector; wherein by rotating the lever in an operational direction of the lever, the second connector is pulled towards the first connector through the pin upon displacement of the engageable hole so as to be fitted into the first connector; wherein the engageable hole is shaped such that the lever is automatically raised in the operational direction of the lever at a position where the pin is inserted into an inlet of the engageable hole.

Abstract: When low-quality iron ore is used as a coal liquefaction catalyst, in order to improve its catalytic activity it is subjected to one or a combination of reduction, heat-treatment, or washing with or immersion in water for a long period of time so as to remove catalyst poisons before it is used as a catalyst. When high-quality iron ore is used, it is first reduced with carbon monoxide and then used as a catalyst.

Abstract: When low-quality iron ore is used as a coal liquefaction catalyst, in order to improve its catalytic activity it is subjected to one or a combination of reduction, heat-treatment, or washing with or immersion in water for a long period of time so as to remove catalyst poisons before it is used as a catalyst. When high-quality iron ore is used, it is first reduced with carbon monoxide and then used as a catalyst.

Abstract: A speaker in which a voice coil bobbin (4) is connected through a mechanical filter to vibrating members (11, 14) for limiting the reproducing frequency band in predetermined range by the mechanical filter, and a speaker system employing the speaker. A pneumatic suspension V is used as the mechanical filter to eliminate the variations in the reproducing frequency band even for long term usage.

Abstract: A transducer such as used for an electro-dynamic loudspeaker adapted to convert an electric signal into a mechanical motion or, a moving coil type velocity sensor adapted to convert a mechanical motion into an electric signal. The so-called "Bl force factor," representative of the product of the magnetic flux density B and the length l of the main coil, is so controlled as to be made constant, whereby the linearity of the transducer is improved.