Abstract: The invention provides a composition for hologram recording having low curing shrinkage and capable of satisfactorily forming a thick holographic coating, a method of curing the same, and a cured article. The composition for hologram recording comprises a cationically polymerizable compound, a compound whose refractive index differs by 0.005 or more from that of a cured article of the cationically polymerizable compound, a thermal cationic polymerization initiator, and an optical cationic polymerization initiator. The curing method of the invention comprises the steps of forming the composition for hologram recording into a liquid film; heating and partially curing the liquid film; and irradiating the partially heat-cured semi-cured film with coherent light and inducing photocuring in order to form an interference pattern. The cured article of the invention is obtained by the aforementioned curing method.

Abstract: The top surface of an electrode type vaporizer water container has a water inlet covered by a safety cover having an apertured concave portion through which the terminal pins of the electrodes are exposed. A detachable electric power source connector is insertable into the concave portion for engagement with the terminal pins for supplying power to the electrodes. A stopper pin on the connector cooperates with a stopper projection on the container adjacent the terminal pins to prevent the engagement between the connector and pins unless the cover, which as provided with a stopper pin release means, is properly positioned on the container. The engagement of the connector with the terminal pins locks the safety cover in position on the container making it impossible to remove the cover while the connector is so engaged. The safety cover arrangement prevents the supply of water into the container through the inlet with the electrodes electrically energized.