Abstract: A calibration reference element for pH measuring instruments includes a reference liquid with a defined pH value and a tubular bag for holding the reference liquid. The tubular bag consists of a foil that is sealed along a maximum of three sealing edges. A calibration reference system comprised of at least two such calibration reference elements with reference liquids and different pH values. The holder used for a calibration reference element allows it to be positioned so that the reference liquid is conveniently available for calibration. Accordingly, a calibration set includes a holder and calibration reference elements or a calibration reference system.

Abstract: An electrode holder comprises a bottom plate (10) and an electrode arm (100). The bottom plate (10) comprises at least one coupling structure for mounting a container or a sachet holder to it in a defined positional relation to the electrode arm. The electrode arm (100) comprises a clamp (55) to hold an electrode and is equipped to guide an electrode held by the clamp (70) to a container or sachet holder mounted to the at least one coupling structure.

Abstract: The present invention relates to a method for cleaning a phase plate (1) for a transmission electron microscope wherein said phase plate is etched before being irradiated for the first time in the TEM, and is then held in an ultra-pure holding atmosphere until the irradiation in the TEM.

Abstract: The present invention relates to a method for cleaning a phase plate (1) for a transmission electron microscope wherein said phase plate is etched before being irradiated for the first time in the TEM, and is then held in an ultra-pure holding atmosphere until the irradiation in the TEM.