Abstract: The invention relates to a method of adjusting a desired spectrum of light emitted by a gas discharge lamp during its operation, said gas discharge lamp comprising a first ionizable substance and a second substance which is less readily ionizable than the first substance. According to the invention, the gas discharge lamp is operated such that gases of both substances cans be excited, while the partial pressure of the first substance is adjusted in dependence on the desired spectrum. For this purpose, for example, the current through the lamp may be modulated. In an alternative embodiment, this is suitably achieved in that the partial mercury pressure is varied, for example through an adjustment of the temperature of a mercury amalgam present in the gas discharge lamp. The invention also relates to a gas discharge lamp whose color can be varied during its operation, and to a luminaire provided with a supply for such a lamp.

Abstract: A process for preparing membrane layers employing an apparatus suitable for plasma surface treating (e.g. forming a membrane layer on a substrate) which comprises a plasma generation section which is operable at least at substantially atmospheric pressure and is in communication via at least one plasma inlet (e.g. a nozzle) with an enclosed plasma treating section which is operable at a lower pressure than the plasma generation section, and wherein the plasma treating-section is in communication with an inlet for a fluid (e.g. polymerizable) reactant. A plasma beam generated in the apparatus and containing at least one fluid reactant impinges on the surface of a substrate to form a membrane layer.

Abstract: An apparatus suitable for plasma surface treating (e.g., forming a membrane layer on a substrate surface) comprises a plasma generation section which is operable at least at substantially atmospheric pressure and is in communication via at least one plasma inlet (e.g., a nozzle) with an enclosed plasma treating section which is operable at a lower pressure than the plasma generation section, and wherein the plasma treating-section is in communication with an inlet for a fluid (e.g., polymerizable) reactant used to form a layer on the substrate surface.

Abstract: A method of treating substrate surfaces with the aid of a plasma such as etching, deposition etc. In the practice of the method, the plasma flows from its place of generation to the treatment-chamber, and in which method the plasma-generator is flushed through with a flushing gas. Preferably, and firstly after the flushing gas has passed the cathodes, the reactant is fed to the plasma-generator. The invention includes the reactor necessary for carrying out the method.