Abstract: The invention is regeneration and recirculation of nitrogen oxides in the exhaust gas of a nitric acid plant without using any material current and heat energy other than that generated in the process of producing nitric acid. Nitrogen oxide is recovered by at least two adsorbers each containing an acid resistant zeolite molecular sieve and operating in an alternate heat cycle; adsorption occurring at 20-40 degrees C. and regeneration at 300-350 degrees C. The hot gas exiting from the oxidation unit used in the production of nitric acid is used to regenerate the adsorbers and the nitrogen oxides set free during the said regeneration are introduced into the main feed stream of the nitric acid plant. In the final stage of the regeneration the adsorbers are cooled by rinsing them with exhaust gas or air at a temperature of 20-40 degrees C.

Abstract: An X-ray system for patient diagnostic services in which the patients are X-rayed at several locations and picture amplifiers pick up the X-ray images and are associated with television cameras which transmit video signals both to a monitor at the X-ray location and to a video signal distributor which delivers signals from a selected camera to a central photographing unit. This unit has a further video monitor, an optical system and shutter and means for replaceably positioning films in the focal plane of these opticals. The exposed film is continuously developed.

Abstract: A between-lens shutter assembly for photographing devices comprising at least two, preferably three rotary plates with axes parallel to the axis of the lenses. Each plate comprises an opening. When the plates are rotated with common speed, the openings move from evenly distributed directions towards the inside opening of the lenses, completely uncover it, then in continued movement close the inside opening again. This way identical opening and closing characteristics and times are provided.In a method using the shutter assembly exposures are taken from television pictures, in which the length of the exposure period is adjusted to be equal to the period of a television picture and the duration of either an opening or closing section, whereby uniform illumination is ensured for the exposure.The invention can be used mainly for the precise photographing of X-ray pictures displayed on the screen of a television monitor.