Abstract: Disclosed is a structural material excelling in lightness of weight, strength, flexural modulus and other properties, being made from polyamide resin reinforced with continuous fiber and/or long filament reinforcing material. This structural material can be fabricated by a monomer casting method by arranging said fiber reinforcing material preliminarily in a desired shape, putting it into a mold, pouring molten &ohgr;-lactams containing a polymerization catalyst and an initiator into said mold, and heating to obtain polyamide resin.

Abstract: The invention discloses a method for determining the inner diameter of the hollow portion of a laminate and is intended to design a laminated rubber support having an appropriate shape.

Abstract: A laminated rubber bearing comprising a columnar-shaped viscoelastic body 5, a plurality of viscoelastic members 4, and an external binding body 1 disposed in the periphery of these components. The external binding body 1 is a laminated body consisting of alternating rigid plates 3 and rubber-like elastic plates 2 with rubber-like elastic plates 2 disposed between external peripheral regions of the rigid plates 3. The viscoelastic members 4 are disposed inside of those rubber-like elastic plates 2 of the external binding body 1 so that the viscoelastic members 4 fill up clearance between the rigid plates 3 inside of respective rubber-like elastic plates 2. A cylindrical cavity 6 open at both ends thereof extends through the viscoelastic members 4 and the rigid plates 3. A viscoelastic body 5, an elastic body, or viscous substance having cubage greater than that of the cylindrical cavity 6 is forcedly inserted in the cylindrical cavity 6.

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.

Abstract: A golf club comprising a club head having a mechanical impedance with a primary minimum value in a region of frequency in which the mechanical impedance of a ball to be struck takes a primary minimum value. Mechanical impedance is defined as the ratio of an external force applied to one point of the ball (or the club head) over the response speed of another point of the ball (or the head) when the force is applied.