Abstract: A current transfer brush with several slider members made of stacked arrangement of foils of highly graphitized graphite extending at least approximately perpendicular to the contact surface of the brush. At least one of the two flat sides of at least some of the graphite foils can be provided with a layer of an electrically conductive material.

Abstract: In a current transfer brush which includes a frame element holding together a flexible slider member containing several graphite fibers which are at least partly coated with an electrically conducting material, the slider member is made of a stack of a plurality of mats of highly graphitized graphite fibers, the mats extending at least approximately perpendicular to the contact surface of the brush with at least some of the fibers in mats coated with an electrically conducting material in order to give improved electrical characteristics for the brush over brushes utilizing a graphite block as the slider member, with the brush particularly useful in commutator machines.

Abstract: A method for manufacturing a photo cathode with a stacked arrangement of perforated double layer films each including two outer electrically conductive layers of a material with a high atomic number and an insulating layer disposed between them by first providing a highly insulating plastic film acting as the insulating layer, on both sides with an electrically conductive layer; subsequently providing each of these two electrically conductive layers so prepared with a hole pattern such that the holes of the two layers are opposite each other; and finally, removing those parts of the plastic film which close off the holes of the electrically conductive layers. This method avoids difficulties in the manufacture of highly insulating plastic layers.

Abstract: A photocathode for electroradiographic and electrofluoroscopic apparatus which contains a stack arrangement of perforated foils of a material with a high atomic number, in particular, double layer perforated foils with two electrically conducting outer layers and an insulating layer arranged in between which obtains relatively high sensitivity and high resolution permitting its use in medical diagnostic apparatus is described along with method of manufacturing the photocathode.

Abstract: A solar cell with semiconductor body consisting of single crystal semiconductor whiskers which are grown on a substrate surface permitting relatively inexpensive manufacture and high efficiency of the solar cell is disclosed.

Abstract: A solar cell with semiconductor body consisting of single crystal semiconductor whiskers which are grown on a substrate surface permitting relatively inexpensive manufacture and high efficiency of the solar cell is disclosed.

Abstract: The surface of an intermetallic niobium compound or niobium alloy to be polished is electrically shunted across a niobium part and immersed in electrolyte together with the latter permitting relatively thick surface layers of niobium compounds of high quality which are used for superconducting a-c apparatus to be produced.

Abstract: An improved method of manufacturing a tubular conductor which consist of a niobium layer and a copper layer, in which one side of a tube of electrolytic copper is plated with niobium by fusion electrolysis and the tube section thus produced, then drawn in several cold drawing passes to reduce the outside diameter and the wall thickness of the tube to form a longer tube, resulting in simplified production of seamless tubes, particularly useful in superconducting cables and having good mechanical, thermal and electrical contact between the niobium and copper layers.

Abstract: A method of producing a conductor for a superconducting cable or the like is disclosed. The conductor is made up of at least niobium and copper of which the copper is an electrically normal-conducting metal. The method includes heating a niobium carrier to a temperature between 150.degree. and 800.degree.C in a vacuum having a residual gas pressure of at most 10.sup.-.sup.4 Torr, and evaporating copper unto the niobium carrier to form a tightly adhering copper layer thereon. If required, the conductor can be produced to include other electrically normal-conducting metals.

Abstract: A method for manufacturing tubular conductors which consist of a niobium layer and a layer of normal electrically conducting metal in which a copper body of rectangular cross section is covered with niobium on one wide and two narrow sides by means of fusion electrolysis and the resulting body then rolled to form a ribbon which is then bent to form a tube with the niobium flanges at the two edges of the ribbon abuting and welded together by electron beam welding. Tubular conductors made according to the method of the present invention are particularly suited for use as superconducting cables.

Abstract: A hollow niobium body, rotatable about a horizontal axis, is arranged for partial immersion in an electrolyte of H.sub.2 SO.sub.4, HF and H.sub.2 O. A generally concentric opening at one end receives a cathode. Evolved gases rise therefrom and escape into a vapor space above without contacting the immersed surfaces of the niobium body. The cathode is hollow and is perforate in the portion introduced into the body in order to feed electrolyte into the body. For polishing, constant electric voltage is applied between the hollow niobium body and the cathode and adjusted in such a manner that damped current oscillations occur which are superimposed on the electrolytic current. Not later than after the complete decay of the current oscillations, the voltage is turned off until the oxide layer built up during the current oscillations is dissolved.