Abstract: A process for producing a concrete product, which includes a step of preparing a primary concrete by mixing a super dry consistency concrete having a unit amount of water of at most 100 kg/cm.sup.3, a step of preparing a secondary concrete by weighing a suitable amount of the primary concrete and adding at least water, a water reducing agent and a setting accelerator thereto, followed by remixing, and a step of molding the secondary concrete in a formwork.

Abstract: A thermionic cathode structure comprises two parallel thermionic electron emitter elements which are made of a heat resistant and electric conductive inorganic compound. Each of them has one end electrically closed and the other end functioning as a current feeding port.

Abstract: A charged particle emission source structure comprising a needle-like electrode for emission of charged particles, a reservoir for a liquid metal for wetting the surface of the needle-like electrode, heat-generating support members for heating the liquid metal and holding the reservoir or the needle-like electrode, and an extraction electrode for applying an electric field as between it and the needle-like electrode, which is characterized in that conductive partitions hardly wettable with the liquid metal are provided between the heat-generating support members and the reservoir or the needle-like electrode.

Abstract: An electron gun for high brightness including a LaB.sub.6 single crystal cathode having a (100) plane on at least part of a main electron beam emission surface of a cathode tip having a top and a Wehnelt having a tapered surface defining an interior angle similar to or greater than a vertical angle of said cathode tip.

Abstract: A thermionic emission cathode of a single crystal made of the calcium hexaboride type crystaline structure comprises a top surrounded by natural face inherent to the axial direction of the single crystal.

Abstract: A thermionic emission cathode comprises a cathode tip made of an alkaline earth metal or rare earth metal hexaboride, a metallic support for supporting a base of said cathode tip and a reaction barrier layer comprising colloidal carbon and a reaction barrier material which bonds said cathode tip and said metallic support in one body.

Abstract: A thermionic cathode supporting device which comprises an electroconductive member adapted to support a thermionic cathode tip and a tip supporting heaters which hold said tip, a pressing means for resiliently pressing the above mentioned members from the outside thereof. The device is so arranged that the pressing force is easily adjustable and can be miniaturized, and applicable for the various different types of cathode devices of an electron gun or the like.