Abstract: A thermoelectric device that realizes miniaturization and densification, an optical module incorporating the thermoelectric device, and their production method. N-type thermoelectric elements 51 and p-type thermoelectric elements 52 are arranged orthogonally and alternately, on the XY-plane, in a matrix consisting of at least four elements in total in a row and at least four elements in total in a column. All the thermoelectric elements 51 and 52 have a size of at most 250 &mgr;m in the X and Y directions. At most four thermoelectric elements nearest to an n-type thermoelectric element 51 are of p type, and at most four thermoelectric elements nearest to a p-type thermoelectric element 52 are of n type. The thermoelectric elements 51 and 52 are bonded through metallic bonding materials to electrodes 53 having the shape of a rectangle or a rounded rectangle formed on an insulating substrate 54.

Abstract: The present invention relates to a method of producing a functionally grant material whose components and structure are continuously adjusted by the coating, plating and powder metallurgy techniques to change its function in turn and provide a method of producing a functionally gradient material superior in heat-resistance, corrosion-resistance and resistance to thermal fatigue by distributing a third component having a lower Young's modulus or formed of high-strength material sufficiently durable to the fracture strength among ceramics as a first component and metals or other ceramics as a second component to change the function.

Abstract: In the cooling wall of a regenerative cooling rocket combustion chamber, the throat portion thereof in which the heat load is highest is formed of a porous material having a perspiring cooling action. The other portion in which the heat load is relatively low is designed to be cooled by conventional forced convection. By such a composite cooling system, a high cooling effect is provided and yet the pressure loss in the cooling passages is small and light weight and long life of the engine are attained concurrently.

Abstract: A method of producing rocket combustors wherein in forming an outer cylin by a powder metallurgical method on the outer side of a cylinder provided on its outer periphery with a cooling wall of channel construction having a plurality of grooves, a low-melting alloy is used as a filler to be filled into the grooves. It is also possible to form the outer cylinder after forming a Cu plating shell on the periphery of the inner cylinder filled with the low-melting alloy.

Abstract: A method of producing rocket combustors wherein in forming an outer cylin by a powder metallurgical method on the outer side of a cylinder provided on its outer periphery with a cooling wall of channel construction having a plurality of grooves (14), an Ni electroforming layer is formed on the outer side of the outer cylinder, and also a method of producing rocket combustors wherein an outer cylinder is of multilayer construction having two or more layers.

Abstract: The present invention is directed particularly to an improved method using owder metallurgy for the manufacture of the grooved cooling wall of a liquid-propellant rocket combustion chamber. The surface of an inner cylinder constituting the cooling wall is formed with cooling grooves, and these grooves are densely filled up with a filler such as paraffin wax. Thereafter, metal powder which will provide an outer cylinder is compression-molded to a predetermined thickness around the inner cylinder. This metal powder is the same material as the material of the inner cylinder. After the paraffin wax which is the filler is evaporated and removed, the compression-molded metal powder body is sintered in a furnace. During this sintering heat treatment, the inner and outer cylinders are rigidly joined together by the sintering reaction between the atoms of the inner cylinder and the atoms of the metal powder.

Abstract: Disclosed is a process for producing metallic chromium sheets having satisfactory mechanical properties directly from metallic chromium powders by successive steps of rolling (or compacting), sintering, re-rolling and annealing.

Abstract: A packing material unit for use in liquid-gas contact apparatuses, which comprises outer and inner rings, and a plurality of pairs of arched filaments positioned side by side such that their curved outer surfaces are oriented alternately to opposite sides of the plane involving the outer and inner rings to form a plurality of circular or elliptic loops arranged about an imaginary circle which is concentric with the outer and inner rings. A connecting member is bridged between intermediate portions of each pair of the filament. A plural number of reinforcing members extend between apex portions of oppositely arched filaments of adjacent filament pairs. The connecting members and reinforcing members serve both to prevent the interlocking of adjacent packing material units and to improve mechanical strength of the unit.