Abstract: The formation of lines of the order of 8 Angstroms wide is achieved using a tunneling current through a gas that changes to provide a residue that is the basis of the line. The tunneling current energy is tuned to the energy required to dissociate the gas.

Abstract: This method involves the deposition of free metal atoms (4) from the apex (5) of a pointed tip (1) supported at a distance of 10 to 20 nm from a substrate (2). The atoms (4) are being field-desorbed under the influence of a strong electric field existing between the tip (1) and the substrate (2). With the tip (1) being moved across the substrate (2), a narrow trace (6) of metal atoms will be deposited on the substrate.

Abstract: The dilution refrigerator operates by sucking a .sup.4 He-rich mixture from a tank and returning it to the tank through a superleak. Thereby the .sup.3 He is separated and returned to the .sup.3 He-rich content of the tank. By this cycling process, a drop in temperature is obtained at the exit of the superleak and through re-mixing of the .sup.3 He with the .sup.4 He. Cycling of the liquid .sup.3 He-.sup.4 He mixture is performed by a bellows pump maintained in a container 16 at a temperature below 2.degree. K. and by specially designed valves comprising a steel ball as a plug and a gold ring as the valve seat.