Abstract: A halogenated organic compound is introduced into a plasma. In the plasma state, substances are very reactive and chemical substances which are not readily decomposed such as halogenated organic compounds are decomposed in a short time. Specifically, in a high-temperature plasma exceeding 10,000.degree. C., almost all molecules are considered to dissociate into atoms. A reactive substance such as water is introduced into a plasma together with a halogenated organic compound. The decomposed halogenated organic compound is caused to react with the reactive substance, for preventing the decomposed organic compound from returning to its original state.

Abstract: A mixed gas is contacted with a non-carbonaceous adsorbent while irradiating the adsorbent with an electromagnetic wave having a frequency of 1 MHz to 25 GHz, such as a microwave, so that a gas component having a smaller coefficient of dielectric loss is selectively adsorbed by the adsorbent. A gas adsorbed on an adsorbent may be desorbed therefrom by contact with a desorbing gas while irradiating the adsorbent with the above electromagnetic wave.

Abstract: A nitrogen oxides-containing gas is contacted with a solid catalyst in the presence of methyl tert-butyl ether as a reducing agent for the conversion of the nitrogen oxides into molecular nitrogen. A supported catalyst including an alumina carrier having Pt, Rh or Ru supported thereon is desirably used as the solid catalyst.

Abstract: A halogenated organic compound is introduced into a plasma. In the plasma state, substances are very reactive and chemical substances which are not readily decomposed such as halogenated organic compounds are decomposed in a short time. Specifically, in a high-temperature plasma exceeding 10,000.degree. C., almost all molecules are considered to dissociate into atoms. A reactive substance such as water is introduced into a plasma together with a halogenated organic compound. The decomposed halogenated organic compound is caused to react with the reactive substance, for preventing the decomposed organic compound from returning to its original state.

Abstract: An exhaust gas cleaner comprising a catalyst carried on a heat-resistant ter, the catalyst comprising (a) one or more alkali metals, (b) one or more metals selected from the group consisting of Zn, Sn and transition metals excluding platinum-group metals, and (c) one or more rare earth metals, and a method of cleaning an exhaust gas with it. Alkali metals may be added to a fuel.

Abstract: An exhaust gas cleaner comprising (a) at least one filter made of a heat-resistant and electrically insulating material for trapping floating fine particles in an exhaust gas; and (b) at least a pair of electrodes stacked with the filter alternately, voltage being applied between the adjacent electrodes to burn electrically conductive and burnable fine particles trapped in the filter by heat generated by a current flowing between the adjacent electrodes, and the direction of the flow of the exhaust gas in the filter being essentially parallel to that of the laminate surface of the electrodes. The filter may carry a catalyst which functions to reduce harmful gas components in the exhaust gas.

Abstract: An exhaust gas cleaner comprising a catalyst carrier on a heat-resistant filter, the catalyst comprising (a) one or more alkali metals, (b) one or more metals selected from the group consisting of Zn, Sn and transition metals excluding platinum-group metals, and (c) one or more rare earth metals, and a method of cleaning an exhaust gas with it. Alkali metals may be added to a fuel.

Abstract: A rotating drum of a magnetic recording/playback apparatus is fitted with a rail which extends in the radial direction of the drum. A head assembly has magnetic heads, grooves engaging the rail, and a stopper adapted to engage the rail. In this arrangement, each magnetic head is automatically located in a predetermined position when the head assembly is set in place on the rotating drum after the head assembly, moved in the radial direction of the drum so that the grooves are guided by the rail, is prevented from moving by the stopper. In this manner, the magnetic heads can be accurately positioned with ease. Thus, even a user can easily replace the head assembly.

Abstract: A halogenated organic compound is introduced into a plasma. In the plasma state, substances are very reactive and chemical substances which are not readily decomposed such as halogenated organic compounds are decomposed in a short time. Specifically, in a high-temperature plasma exceeding 10,000.degree. C., almost all molecules are considered to dissociate into atoms. A reactive substance such as water is introduced into a plasma together with a halogenated organic compound. The decomposed halogenated organic compound is caused to react with the reactive substance, for preventing the decomposed organic compound from returning to its original state.