Abstract: Conventionally, it has been necessary to vary the cooling capacity to control the temperature of the growth face when a crystal thin film is grown, and it has been difficult to greatly vary the rate of flow of cooling water in the case of water cooling. Therefore the system needs to be of large scale and the production cost is high if the rate of flow of cooling gas is greatly varied in the case of gas cooling. According to the invention, the problems are thoroughly solved, and the control of the temperature of the surface from which a crystal thin plate is grown is easily performed, thus producing a crystal thin plate at low cost.

Abstract: A process for preparing reinforced plastic plates comprising molding a thermosetting resin in a mold to form a plate-like body, forming spaced-apart slits extending in the longitudinal direction of the plate-like body with a spacing distance of 1 m at the most just after setting of the resin, suspending the plate-like body from one longitudinal end thereof, fixing a weight to the lower portion of the plate-like body, confining the plate-like body in the horizontal direction by at least one pair of fixing boards, heat-curing the plate-1ike body in the said state, and embedding an elastic resin in said slit portions of the plate-like body.