Abstract: An object is to prevent an operation defect and to reduce an influence of fluctuation in threshold voltage of a field-effect transistor. A field-effect transistor, a switch, and a capacitor are provided. The field-effect transistor includes a first gate and a second gate which overlap with each other with a channel formation region therebetween, and the threshold voltage of the field-effect transistor varies depending on the potential of the second gate. The switch has a function of determining whether electrical connection between one of a source and a drain of the field-effect transistor and the second gate of the field-effect transistor is established. The capacitor has a function of holding a voltage between the second gate of the field-effect transistor and the other of the source and the drain of the field-effect transistor.

Abstract: A color electrophotographic apparatus employing a plurality of image forming units each including a photoreceptor and a corona charger, and using toner. In the apparatus, the image forming units are arranged to be displaceable, with an exposure position of an exposure device and a transfer position of a transfer paper holding member being fixed. During image formation, the image forming unit is moved to a predetermined position, and the obtained color image transferred onto paper sheet on a transfer paper holding member. Each of the image forming unit has a first image forming position confronting the transfer paper holding member, and a second image forming position different from the first image forming position.

Abstract: Pyridoindolobenzodiazepines, including 1,2,3,4-tetrahydropyrido[4',3':2,3]indolo[1,7-ab][1,4]benzodiazepine-9(8H) -ones and 1,2,3,4,8,9-hexahydro- and 1,2,3,4,4a,8,9,14a-octahydropyrido[4',3':2,3]indolo[1,7-ab][1,4]benzodiaze pines, are useful as tranquilizers.