Abstract: An underwater acoustic communication system includes a transmission device including N transmitters, and a reception device. The reception device includes M (M is an integer of two or more) receivers configured to receive M reception signal sequences corresponding to N transmission signal sequences transmitted from the N transmitters through sound waves, a beam former configured to suppress multipath waves other than direct waves of the M received reception signal sequences and to generate L (L is an integer of two or more) signal sequences from the M reception signal sequences, and a signal estimation unit configured to estimate the N transmission signal sequences based on the L generated signal sequences.

Abstract: A kneader/stirrer includes two rotary shafts extending parallel to each other in the processing chamber, and first and second regular triangular impellers mounted to the respective rotary shafts. The first impellers are located at the same axial positions as the respective first impellers. The impellers are fixed to the respective rotary shafts at points offset from the centers of the respective impellers in a predetermined direction by a predetermined distance such that when the two rotary shafts rotate in the same direction at the same speed, each pair of first and second impellers are eccentrically pivoted, with one apex of one of the pair of impellers kept in contact with or in close proximity to the contour of the other impeller, thereby scraping off polycondensation resin (material to be processed) adhered to the other impeller.

Abstract: A two-shaft continuous kneading machine is disclosed wherein airtightness in a housing is assured by a simple means without using a mechanical seal. A magnetic coupling mechanism is formed between the mechanism in the housing (2) including shafts (3) of the kneading machine (1) and a carrier (5) arranged outside the housing (2). The magnetic coupling mechanism includes gear portions (3c) formed on the shafts (3), a ring gear (4) rotatably supported in the housing (2) on the outer periphery of the axial ends of both shafts (3), and a carrier (5) rotatably supported coaxially with the ring gear (4) in the outside of the housing (2). When the carrier (5) is driven, the ring gear (4) rotates because of the magnetic action between magnet portions (4b, 5b), and the shafts (3) rotates because of the meshing of the gear portions (3c, 4a). Since the inside of the housing can be sealed, airtightness can be assured.

Abstract: A kneader/stirrer includes two rotary shafts extending parallel to each other in the processing chamber, first and second regular triangular impellers mounted to the respective rotary shafts. The first impellers are located at the same axial positions as the respective first impellers. The impellers are fixed to the respective rotary shafts at points offset from the centers of the respective impellers in a predetermined direction by a predetermined distance such that when the two rotary shafts rotate in the same direction at the same speed, each pair of first and second impellers are eccentrically pivoted, with one apex of one of the pair of impellers kept in contact with or in close proximity to the contour of the other impeller, thereby scraping off polycondensation resin (material to be processed) adhered to the other impeller.

Abstract: When starting raw material powder is passed through a pair of rolls (2a), plastic working is applied to the starting raw material powder, and the crystal grain diameter of a metal or alloy constituting a matrix of the powder particle after processed is miniaturized. According to the thus provided alloy powder raw material, the maximum size of the powder particle is not more than 10 mm and the minimum size of the powder particle is not less than 0.1 mm, and the maximum crystal grain diameter of the metal or alloy constituting the matrix of the powder particle is not more than 30 ?m.

Abstract: When starting raw material powder is passed through a pair of rolls (2a), plastic working is applied to the starting raw material powder, and the crystal grain diameter of a metal or alloy constituting a matrix of the powder particle after processed is miniaturized. According to the thus provided alloy powder raw material, the maximum size of the powder particle is not more than 10 mm and the minimum size of the powder particle is not less than 0.1 mm, and the maximum crystal grain diameter of the metal or alloy constituting the matrix of the powder particle is not more than 30 ?m.