Abstract: For improvement in the performance of a PDP, a dielectric layer, deposited on the inner face of the front glass substrate of the PDP and covering row electrode pairs, is formed of a dielectric material having a relative dielectric constant of 9 or less, and a protective layer overlying the dielectric layer includes a magnesium oxide crystal causing a cathode-luminescence emission having a peak within a wavelength range of 200 nm to 300 nm upon excitation by electron beams, and discharge gas filling the discharge space includes 10% or more xenon by volume.

Abstract: A control system for a hydraulic circuit having an on-off valve interposed between the control valve and the actuator for allowing and blocking a flow of hydraulic fluid therebetween in which the control valve and on-off valves are actuated and switched in accordance with an operation signal from an operation device. Pressure sensors are connected to hydraulic lines upstream and downstream of the on-off valves for detecting the pressures in these hydraulic lines, and control unit is operative to calculate, based on the pressures detected by the pressure sensors, a value which reduces the difference between thrusts applied to the actuator and output the calculated value to the control valve while the on-off valves are closed to thereby perform pressure matching control.

Abstract: A working structure having a support and an arm assembly pivotally connected to the support. The arm assembly includes at least two arm members pivotally connected to each other and each pivotally moved by a respective actuator. The second arm member has an external load applied to its front end or working point.