Abstract: A mold 11 having an inner surface coated with a heat insulating film 14 excellent in heat insulation and conformability to a molten resin 20 is clamped with the other mold 12 to form a molding cavity 13. When the molten resin 20 is cooled and solidified in the cavity 13, heat transmission through the mold 11 is suppressed by the film 14 so that a skin layer 23 preferentially grows at the side of the mold 12. Hence, the volumetric shrinkage of the resin 20 during cooling and solidification is selectively absorbed in the deformation of the skin layer 23 separated from the inner surface of the mold 12. As a result, an obtained product has a smooth front surface free from defects such as sink marks. The heat insulating film 14 exhibits the effect to eliminate weld lines, too.

Abstract: When injection-molding a molten thermoplastic resin into a molding having different thicknesses, a void inducing member is set in a cavity corresponding to heavy sections. Then gas pressure is applied passing through a gas passageway to a tip end of the void inducing member, thus forming a void nucleus in the resin adjacent to the tip end of the void inducing member. The void nucleus develops to a void by shrinking force of the resin as the molten resin cools.

Abstract: Disclosed is a method for the production of diamond films, which comprise introducing a diamond-forming gas into a reaction chamber in which a substrate is located, activating the gas in the reaction chamber and depositing diamond on the substrate by decomposition of the gas, wherein the diamond-forming gas is a gas or gas mixture containing hydrogen, oxygen and carbon atoms at an atomic ratio satisfying requirements represented by the following formulae:2.gtoreq.C/H.gtoreq.0.0005, and4.gtoreq.O/C.gtoreq.0.0005.

Abstract: When injection-molding a molten thermoplastic resin into a molding having different thicknesses, a void inducing member is set in a cavity corresponding to heavy sections. Then gas pressure is applied passing through a gas passageway to a tip end of the void inducing member, thus forming a void nucleus in the resin adjacent to the tip end of the void inducing member. The void nucleus develops to a void by shrinking force of the resin as the molten resin cools.

Abstract: Disclosed is a method for the production of diamond films, which comprises introducing a diamond-forming gas into a reaction chamber in which a substrate is located, activating the gas in the reaction chamber and depositing diamond on the substrate by decomposition of the gas, wherein the diamond-forming gas is a gas or gas mixture containing hydrogen, oxygen and carbon atoms at an atomic ratio satisfying requirements represented by the following formulae:2.gtoreq.C/H.gtoreq.0.0005, and4.gtoreq.O/C.gtoreq.0.0005.

Abstract: An expansion injection molding die having a plate forming the die cavity, a backup plate, a core plate, ejector pins inserted through the backup plate and the core plate for separating the molded products from the die cavity, and a gas introducing passage communicating with the pressurized gas source for introducing gas into the die cavity. The plate that has holes through which the ejector pins are injected are formed with hollow portions. In each of the hollow portions, a guide ring is installed so that it is freely movable at least two-dimensionally. A sealing member is installed in an expanded hole portion in the guide ring so that it is in sliding contact with the ejector pin.

Abstract: A process of thermally cracking a heavy petroleum oil wherein the heavy petroleum oil is treated successively in a cracking furnace and then in a perfect mixing type tank reactor. The thermal cracking in the cracking furnace is performed at a temperature at the outlet of the cracking furnace of 450.degree.-520.degree. C. with a conversion of at least 60-75% of the overall conversion rate while the thermal cracking in the tank reactor is performed at a temperature of 400.degree.-450.degree. C. a pressure of from ambient pressure to 1 kg/cm.sup.2 for a period of time of less than 30 minutes but not less than 10 minutes while feeding steam having a temperature of 435.degree.-700.degree. C. to the tank reactor in an amount of 8-20% by weight of the heavy petroleum oil fed to the cracking furnace.