Abstract: An improved packet switching apparatus with multichannel and multi-cast switching functions and a packet switching system using the same which are capable of more simplifying the routing of an internal routing during the integration of the switching apparatus by using a simpler 2.times.2 switch device for a concentration network in order to provide a routing network and a recirculation path and by using a pattern connection characteristic consisting of a column and row.

Abstract: A cathode for an electron tube includes a layer of a electron emitting substance containing alkaline earth metal oxides containing 0.01--20.0 wt % of both a lanthanum compound and a magnesium compound or a lanthanum-magnesium compound disposed on a base metal including nickel as a major component and tungsten as a minor component. The tungsten prevents embrittlement and ensures a continuing supply of fill barium in the electron-emitting substance. The cathode enjoys full interchangeability with the conventional oxide cathode and a 15-30% longer life span.

Abstract: A display combined with a slide projector and liquid crystal projector is disclosed including a light source for emitting light, light collecting means for collecting light emitted from the light source, and image display device having image information so as to enlarge and project an image displayed on the image display device. The image display device includes a first display device for receiving electrical video information and converting it into optical video information; a second display device in which video information is recorded optically; and selecting means for selecting the first or second display device.

Abstract: The present invention relates to a fixed length packet switching apparatus using multiplexers and demultiplexers in which the apparatus has an output buffer-type construction, protects itself from a temporary overflow occurrence of an output terminal and has the construction of the mutual flow control to enhance its entire performance. The present invention can protect the entire operations as well as enhance the entire performance of the switching apparatus by preventing an obstacle of the switching apparatus due to an overflow temporarily generated from an output terminal, process without a loss of excessive cells a traffic phenomenon of one output port in the switching apparatus, reduce the necessary buffer according to the effect of the rate gain and process smoothly input traffic of the internal buffer having a burst characteristic.

Abstract: A cathode for an electron tube has a layer of electron-emissive substance containing alkaline earth metal carbonates having capillary crystals, to which 0.01-20.0 wt % of both a lanthanum (La) compound and a magnesium (Mg) compound or an La--Mg compound, based upon the weight of the alkaline earth metal carbonate, is added. The cathode enjoys full interchangeability with a conventional oxide cathode and a 15-20% longer lifetime.