Abstract: A lubricant contains ester compound made of perfluoropolyether and long chain alkyl carboxylic acid or alcohol. The perfluoropolyether has hydroxyl or carboxyl group at its end. The ester compound is admixed with long chain alkyl amine of from 0.01 to 100 in mole ratio. The long chain alkyl may be partially fluorined or perfluoro alkyl. At least one of phosphoric ester, phosphorous ester and long chain carboxylate ester can be further admixed. A magnetic recording medium can be coated by the lubricant.

Abstract: A magnetic recording medium containing an amine salt of carboxylic acid as the lubricant is disclosed. The amine salt of carboxylic acid means a usual amine salt of carboxylic acid, synthesized from carboxylic acid and an organic amine, an amine salt of perfluoroalkyl carboxylic acid, synthesized from perfluoroalkyl carboxylic acid and an organic amine, and a fluoroamine salt of perfluoroalkyl carboxylic acid, synthesized from a perfluoroalkyl carboxylic acid and a fluorine substituted organic amine. The amine salt of carboxylic acid may be contained in the magnetic layer of the magnetic recording medium or top coated on the magnetic layer. Such amine salt of carboxylic acid exhibits superior solubility in general-purpose solvents and superior lubricating properties to diminish the coefficient of friction. Such lubricating properties are not impaired under hostile conditions, such as low temperature.

Abstract: An optical recording medium including a substrate and a photosensitive layer thereon, the photosensitive layer containing as its major ingredients, the combination of a polymeric binder resin and an indolinospirobenzothiopyran compound represented by the general formula (I): ##STR1## where R.sub.1, R.sub.2 and R.sub.3 are each a hydrogen atom, a halogen atom, an alkyl group containing from 1 to 5 carbon atoms, an alkoxy group containing from 1 to 5 carbon atoms, an alkoxymethyl group containing from 1 to 5 carbon atoms in the alkoxy group, a hydroxymethyl group or an alkylaminomethyl group containing 2 to 6 carbon atoms in the alkyl group. The optical recording medium has a colored image which is very stable against heat and visible light.

Abstract: Described is a magnetic recording medium wherein a thin magnetic metal film is formed as the magnetic layer on a non-magnetic base, and wherein a carboxylic acid perfluoroalkyl ester is coated as the lubricant on the thin magnetic metal film used as the magnetic layer to produce the magnetic recording medium exhibiting good running properties, wear resistance and durability under any operating conditions.The carboxylic acid perfluoroalkyl ester employed as the lubricant in the present invention is a compound represented by the general formulaRCOO(CH.sub.2).sub.j C.sub.k F.sub.2k+1wherein R in the general formula stands for a hydrocarbon residue and j.gtoreq.0 with k.gtoreq.4.

Abstract: A floor system for seismic isolation comprises a floor member disposed above a foundation, a plurality of supports for supporting the floor member in a manner to be movable in a horizontal direction and a number of restoring devices disposed between the foundation and the floor member and each comprising first and second restoring units. The first and second restoring units have the same structure and are arranged in the directions perpendicular to each other.

Abstract: A seismic isolator has a sliding plate fixed on the lower surface of a building, a connecting plate underlying the sliding plate, an elastic first support disposed between the connecting plate and a foundation of the building to support the building, a second support disposed between the connecting plate and the foundation and urged by a biasing force of a spring member such that its upper end is brought into tight contact with the lower surface of the connecting plate, and a jack for adjusting the biasing force of the spring member. A frictional force acting between the sliding plate and the connecting plate is larger than that between the connecting plate and the upper end of the second support.

Abstract: Novel photochromic compounds are disclosed, which compounds are represented by the general formula ##STR1## in which R.sub.1 represents an alkyl group having 1 to 20 carbon atoms, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 independently represent an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a halogen atom, a nitro group, a cyano group or a dimethylamino group, and R.sub.6, R.sub.7 and R.sub.8 independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen atom, and correspondingly 97 to 50 wt % of a film-forming polymer. Photosensitive compositions and materials comprising the compounds are also described.

Abstract: A device for securing a fuel assembly to a nuclear reactor pressure vessel comprises upper and lower tie plates for supporting the fuel assembly at its lower and upper ends, spacers for supporting the fuel assembly at intermediate portions between the both tie plates, a channel box surrounding the fuel assembly, and a stationary handle attached to the upper tie plate. A movable handle is attached to the stationary handle to be vertically slidable with respect thereto and the movable handle is always urged downwardly by a coil spring. Hook members are connected to the stationary handle to be rotatable in accordance with vertical movement of the movable handle such that the lower end of the hook member engages with an upper grid of the pressure vessel when the movable handle is lowered to a low portion and disengages therefrom when the movable handle is lifted to an upper position.