Abstract: The interior of a tube provided for low temperature operation is shielded from the exterior through a plurality of metal ribbons helically looping around the tube in an intertwined relationship and each carrying a welded on conduit for low temperature liquid whereby one of these conduits serves as a primary or outgoing conductor, and the two others serve as return paths; suitable spacers are provided to position the system in a concentric relation; inner and outermost tubes are preferably corrugated and the immediate interior of the outermost tube is filled with superinsulation.

Abstract: A method for producing, by electroforming, a nozzle body having an inner ket surface whose slope can be made variable and, in particular, can be formed to change direction, along its axis of symmetry. An electrolytic metal deposit is applied to a previously produced base body having the negative shape of the nozzle body so as to form the positive nozzle body after which the base body is removed by chemical or mechanical means. The base body is made of a plurality of parts and these parts are aligned with respect to one another in such a manner that the tip of one part is centered and held coaxially with the axis of symmetry either in the tip or in the base surface of another part.

Abstract: A method is provided for separating isotopes of an element where the isots are present in the form of molecules and where the isotopes participate in the vibrations of the molecules and are excited by means of radiation and then separated. Isotopes or elements with a defined nucleon-number are selected in which a shift of the band edges in their absorption spectra is present due to the isotopy effect, and radiation that is used lies within that frequency interval in which the absorption coefficient of one isotope of an isotope mixture or several isotopes of an isotope mixture is greater than that of the other isotope or the remaining portion of the isotopes, respectively.