Abstract: Described is a semipermeable capillary having a tubular semipermeable wall composed of a membrane-forming material (2) and a tubular strengthening layer (1). The tubular strengthening layer includes an elongated tape having mutually overlapped longitudinal edges. The tubular strengthening layer has an open cohesive structure that is embedded in the membrane-forming material whereby the mutually overlapping longitudinal edges are joined together by the membrane-forming material and a continuous phase is formed between the semipermeable wall and the strengthening layer.

Abstract: An improvement is made to an elastic foot of an apparatus by adding reinforcing rings (8) enabling an increased support surface and thereby a better stability of the compact disc player and of other apparatus placed on said player. A judicious use of these reinforcing rings provides advantageous compensation even for dissymmetry due to uneven loading.

Abstract: With vertical playback decks there is a risk that, when the pressure arm is released in the stop mode, the expensive and fragile compact disc may fall out. This risk is overcome by designing the centering piece with a groove arranged in front of the centering diameter and by the provision, at the front end of the centering piece and at the rear wall of the groove, of a bevel edge of about 45.degree. and, at the front wall of the groove, of a bevel edge of between 5.degree. and 10.degree..

Abstract: Method of metallizing, according to a pattern or uniformly, substrates which consist of a resin which contains either throughout its bulk or in a surface layer, a photosensitive semiconductive oxide, which after exposure to light is capable of depositing metal nuclei from a solution of copper ions or ions of a nobler metal, which nuclei are intensified in mass, while by way of pre-treatment the substrate is treated with a dipolar aprotic swelling agent and then with a chemical roughening agent.