Disclosed herein are methods, systems, and non-transitory computer readable media for displaying a clipboard. The piston valve assembly, installed at one end of a piston rod, operates with the inside of a cylinder being divided into upper and lower chambers, and generates a damping force varying according to a moving speed. The female coupling half further includes a valve seated against a dump valve body which relieves pressure in the female half of the coupling to enable easy connection of the coupling halves. Subsequently, a gate dielectric is formed on the sidewalls and bottom of the trench and a gate electrode in the trench without a separate field electrode in the trench.