Abstract: A magnetic head includes a pair of magnetic core halves provided with at least metal magnetic films are combined together so that the metal magnetic thin films of one of the pair of magnetic core halves are abutted on the thin films of the other. A winding slot is provided in the abutting portions between the pair of magnetic core halves to form a front gap and back gap on both sides of the winding slot. The pair of magnetic core halves are bonded together with first bonding glass adjacent to the back gap, and second bonding glass adjacent to the front gap, which as a thermal expansion coefficient higher than that of the first bonding glass.

Abstract: A process for converting nitrogen dioxide into nitrogen monoxide which comprises bringing a gas containing nitrogen dioxide into contact at a temperature ranging from 50.degree. C. to 400.degree. C. with a carbide of a metal selected from the group consisting of chromium, molybdenum, tungsten, vanadium, titanium, tantalum, silicon and boron or a composite carbide of such metals, thereby reducing nitrogen dioxide contained in the gas to nitrogen monoxide.