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The steel slit shear wall, in which stiffness and strength are controlled by altering the length, interval and pattern of slits, has been studied as an earthquake-resisting element with high energy dissipation capacity. Local buckling in each link (the segment between slits) and strength degradation that would cause reduction of energy dissipation capacity can be restrained by increasing the number of slit rows with keeping the strength and stiffness constant. This paper proposes the use of low yield point steel (LY100) for the steel slit shear wall. Expansion of plasticity caused by the significant strain hardening of LY100 makes shear deformation distribution more equal in each slit row and disperses the strain concentrated in the edge of links. Furthermore, the larger maximum rupture strain of LY100 than that of conventional steel reduces the risk of fracture at the edge of link. The advantages of the proposed steel slit shear wall are demonstrated by both the test and analysis.

A system to identify the position where arc discharges occurred on a solar array in vacuum has been developed. The system is composed of a video camera, an A/D converter, a personal computer (PC) and a computer program. Analog video image of the solar array from the video camera is converted to digital one by the AD converter. The digital video image is recorded directly on a hard disk drive connected to the PC during an experiment without dropping any video frames. After the experiment, a picture image is extracted in memory bank from the stored video image by the computer program and is compared with a first frame of the video image. The position of arcs is identified by means of repeating this comparison over all frames. The system is built at a low cost with commercial hardware and reduces the time required for analysis remarkably.

This study describes the development of the sheet feeding mechanism using ultrasonic vibration actuator. It consists of a driving rotor, a sub-rotor, and two sets of piezoelectoric vibrators, which is called the dual vibrator in this paper. That vibrator generates the mode of bending vibration. Driving rotor is rotated by the ultrasonic vibration of the dual vibrator. The driving frequency and amplitude of one vibrator is different from that of the other. In this paper, the motion of driving rotor is analyzed theoretically, and it is confirmed that its rotor can be rotated in the clockwise or counterclockwise direction. As a result of fundamental experiments, it was proved that telephone card could be fed easily, and flat and compact sheet feeding mechanism could be obtained.