A variable capacitor is provided within a radiofrequency power transmission path to a bias electrode, in addition to an impedance matching circuit provided within the RF power transmission path to the bias electrode. The membrane comprises the bridge member comprising an SiO2 film of 20 nm in thickness as a lower layer and an SiN film of, for example, 100 nm in thickness laminated thereon, and a combined light reflective film and membrane-side electrode composed of an Al film of 100 nm in thickness provided on the bridge member. Further it relates to a network access server, an authentication-authorization-and-accounting server, and computer software products for proxying user authentication-authorization-and-accounting messages via a network access server. The at least one wall has a plurality of orifices formed therein that are configured to direct a stream of pressurized air therefrom in a direction that diverges from the fluid droplet path. In a fifth aspect of the present disclosure, an interface select circuit, FIGS.