Abstract: Ge, Si or a Ge-Si alloy are melt-molded to form, for example an optical lens, by heating Ge, Si or a Ge-Si alloy to at least its melting point, and heating a molding die to a temperature above that melting point. The molten material is injected at a predetermined pressure into a cavity of the heated molding die, and then the melt is cooled at that pressure to a temperature just above a temperature at which the melt solidifies. The pressure on the melt is then decreased, and the melt is cooled to the temperature at which it solidifies. The pressure on the solidified melt is increased, and the solidified melt is cooled. After releasing the pressure on the cooled solidified melt, the optical lens, or other molded article, is removed from the die.

Abstract: A fluid speed or direction measuring apparatus utilizes a sensor where an output changes regularly with respect to a temperature change at the resistance-temperature characteristic of a piece of single crystal germanium, thereby converting the temperature change in the single crystal germanium in contact with the fluid into a resistance change, so that the resistance change is converted into voltage, a current or electric power.