Abstract: The pipe of the present invention comprises an ethylene base polymer comprising ethylene and an &agr;-olefin having 3 to 20 carbon atoms, wherein (A) a maximum value of the residual stress is 0.13 MPa or less; (B) the crystallinity is 0.630 to 0.850; (C) a gradient of the crystallinity against a thickness of the pipe is 0.465 or less; and (D) the pipe has a thickness of 5 to 50 mm. It is excellent in a durability, a rigidity and an impact resistance and suited to uses for large diameter pipes receiving a high internal pressure.

Abstract: The pipe of the present invention comprises an ethylene base polymer comprising ethylene and an &agr;-olefin having 3 to 20 carbon atoms, wherein (A) a maximum value of the residual stress is 0.13 MPa or less; (B) the crystallinity is 0.630 to 0.850; (C) a gradient of the crystallinity against a thickness of the pipe is 0.465 or less; and (D) the pipe has a thickness of 5 to 50 mm. It is excellent in a durability, a rigidity and an impact resistance and suited to uses for large diameter pipes receiving a high internal pressure.

Abstract: In a driving unit for an electric motor driven bicycle, a motor (31) has an output shaft coaxial with a crank shaft (39) of a pedal. A planet roller reducer (40) has a sun roller shaft coincident with the output shaft. Through the planet roller reducer (40) and a two-stage reducing gear mechanism (50) for further reducing the output of the planet roller reducer (40), a torque of the motor (31) is transmitted to a driving chain sprocket (4). Provided that the torque of the motor (31) exceeds a predetermined pedaling torque level, the torque is transmitted to the driving chain sprocket (4).

Abstract: A process for producing a novel formamide group-containing copolymer, or a salt thereof, which can be used as a high-molecular weight amino reagent, a starting material for functional high-molecular weight compounds, a starting material for adhesives, a polymer compatibilizer, a resin modifier, etc.