Abstract: An apparatus analyzes liquid samples automatically and continuously by mixing certain reagents within a common arrangement of membrane pumps, mixing chambers and connecting conduits formed in a silicon wafer and evaluating the reaction results with the help of suitable sensors on the silicon wafer, the silicon wafer being of 100 orientation and the structure thereof having been formed by anisotropic etching. Immediately before and after the pump chamber of trapezoidal cross section, there are conduits of a v-shaped or trapezoidal cross section which have a nonlinear flow resistance.

Abstract: A drive arrangement, for example for a writing head, comprising a piezoelectrically actuated lever arrangement (1d) for moving a writing tip (21) in the direction of a recording medium when writing on the recording medium. This drive arrangement is characterized in that a piezoelectric actuator (4) is used, which is separate from the lever arrangement (1d) and in that the lever arrangement (1d) exerts a compressive force on the piezoelectric actuator (4), which is supported against a rigid abutment (section 1b). This drive arrangement can be used for a series of other applications as a positioning drive. Inverse arrangements are also described.