Abstract: Fibers as a reinforcing substrate are impregnated with the particles of polytetrafluoroethylene and pressed into a shape at the melting point of polytetrafluoroethylene. Alternatively, the reinforcing substrate sandwiched between polytetrafluoroethylene sheets is pressed into a shape at the melting point of polytetrafluoroethylene. In either case, the shaped article is then exposed to an ionizing radiation in an oxygen-free atmosphere at the melting point of polytetrafluoroethylene. The inherent characteristics of the polytetrafluoroethylene, i.e., heat resistance, chemical resistance, abrasion resistance and lubricity, are retained and yet radiation resistance and resin transparency are imparted.

Abstract: A product having reduced friction and improved abrasion resistance comprises a formed resin containing at least one fluorine-containing polymer which is exposed to an ionizing radiation. The formed resin may include from 1 to 100 weight percent of the fluorine-containing polymer in the form of powder, and from 99 to 0 percent of a high molecule polymer which is not exposed to the ionizing radiation. The fluorine-containing polymer is preferably exposed to the ionizing radiation for a total dose of from 1 KGy to 10 MGy in the absence of oxygen at a temperature not lower than the melting point of a starting fluorine-containing polymer.

Abstract: Ultra-high-strength refractory silicon carbide fiber having a decomposition temperature of not less than about 1800K, a breaking strength of not less than about 5 GPa, and a modulus of elasticity of not less than about 300 GPa is disclosed, which is obtained by irradiating a precursor comprising organosilicon compound fiber with an ionizing radiation in a mixed carrier gas comprising a reactive gas and a first inert gas to render the precursor infusible and calcining the irradiated precursor in a second inert gas. Irradiation damage can be minimized, and no oxygen is incorporated into the fiber.

Abstract: A super heat-resistant silicon carbide fiber has an oxygen content of less than 0.1% by weight. In a process for producing the super heat-resistant silicon carbide fiber, a precursor fiber prepared by spinning a polycarbosilane having an oxygen content of less than 0.8% by weight is irradiated with a radiation in an oxygen-free atmosphere or in vacuo to make the precursor fiber infusible. The infusibilized fiber is fired in an oxygen-free atmosphere or in vacuo at a temperature of from 1000.degree. to 2200.degree. C. without exposure to an oxidizing atmosphere; or stabilized in the same atmosphere at a temperature of from 300.degree. to 600.degree. C. without exposure to an oxidizing atmosphere and fired in an oxygen-free atmosphere or in vacuo at a temperature of from 1000.degree. to 2200.degree. C.

Abstract: A high purity and high strength inorganic silicon nitride continuous fiber substantially composed of Si and N with excellent properties can be provided. A method of producing the fiber is also disclosed.

Abstract: A high purity and high strength inorganic silicon nitride continuous fiber substantially composed of Si and N with excellent properties can be provided. A method of producing the fiber is also disclosed.

Abstract: An alanine dosimeter that enables accurate and simple measurement of the absorbed dose of an ionizing radiation is disclosed. The dosimeter uses as an alanine binder agent at least one member selected from among synthetic rubbers, and natural rubber.

Abstract: A stable aqueous dispersion of unexpectedly high molecular weight polytetrafluoroethylene, containing no additives such as dispersing and emulsifying agents, is prepared by radiation-polymerizating tetrafluoroethylene monomer in an aqueous phase in the absence of dispersing or emulsifying agent.