Abstract: The tennis racket frame according to the present invention has a total weight of 230-300 g and total length of 52-67 cm and a periodic damping ratio of 0.5-4.0%, which is constituted of a fiber reinforced resin composed of polyamide resin reinforced by a continuous fiber and/or long fiber reinforcing material. A resin layer containing a non-woven fabric may be provided at the inside, outside or/and in the middle of the fiber reinforced resin layer. Because of this structure, the tennis racket frame of the present invention can be light in weight and compact in size with a large periodic damping property, making it possible to avoid tennis elbow.

Abstract: Disclosed are a speaker diaphragm formed from a polyamide resin reinforced with continuous fiber reinforcements and/or long fiber reinforcements, and a production method therefor. The speaker diaphragm has high internal loss and excellent specific modulus so as to produce a large sound volume, and has reduced high frequency distortion, flat frequency characteristics and reduced sound distortion for the capability of faithfully reproducing low volume sound.

Abstract: A reaction injection machine utilizing a plurality of reactant liquids, including a plurality of supply vessels for containing the reactant liquids, an injection tank and a fixed quantity metering device including a plurality of metering tanks provided for the supply vessels, a plurality of metering pipes for connecting the supply vessels with the metering tanks, and a plurality of supply pipes for supplying to the injection tank the reactant liquids metered in the metering tanks, whereby the reactant liquids are metered in the metering tanks so as to be supplied to the injection tank through the supply pipes and then, are stirred for mixing in the injection tank so as to be injected into a mold immediately after having been mixed.