Abstract: A method for recording and reproducing information on or from an optical recording medium, which comprises:recording information by illuminating light to the optical recording medium which is equipped as a recording film with a thin film comprising dispersed fine grains of a material capable of showing a metal-insulator transition to cause the metal-insulator transition owing to the heating effect of the light; and reproducing the information by utilizing changes in optical characteristics owing to a plasma resonance absorption by the fine grains dispersed in the thin film. The method of this invention permits high-density recording with high sensitivity and upon reproduction, enables reproduction of record with a high signal/noise ratio. The recording medium obtained by this method is an erasable optical recording medium, which permits its reutilization for recording and reproduction after erasure of the previously-stored record.

Abstract: There is disclosed a method of joining Ni-base heat-resisting alloys which comprises forming, under an inert atmosphere, an aluminum layer on at least surfaces to be joined of a constructional member which has been divided into a plural number of parts composed of a Ni-base heat-resisting alloy reinforced by a .gamma.' phase in Ni.sub.3 Al system, followed by heating the parts so that said aluminum is dispersed in said Ni-base heat-resisting alloys, the joining portion (joint) contains substantially no .beta.-NiAl phase and a .gamma.'-Ni.sub.3 Al phase is dispersed therein to join the parts. The joint provided by the method according to the present invention has been improved in its strength and corrosion resistance at a high temperature. Further, the method according to the present invention can be carried out with a high degree of freedom in supplying a joining filler metal.

Abstract: Disclosed is a method of measuring the deterioration degree of heat resistant parts made of a 12% Cr steel containing at least one of Mo and W and used under high temperatures on the basis of the amount of Laves phase precipitated within said 12% Cr steel.

Abstract: A method of determining the degree of deterioration of a heat-resistant ferritic steel part, such as that of Cr-Mo-V steel practically applied in a region of high temperature from at least one of the crystallization factors such as the particle size, interparticle distance and crystallization density of a carbide, particularly V.sub.4 C.sub.3 crystallized out in said ferritic steel part.

Abstract: A watch case made of an alloy consisting essentially of 30 to 45% by weight of Cr, 2.5 to 5.0% by weight of Al and the balance essentially Ni, said alloy having been subjected to an aging treatment. The watch case is high in hardness and corrosion resistance and presents a good mirror-like surface.