Abstract: An optical disc reproducing apparatus reproduces an optical disc having an information recording surface on which record information and control information are recorded. The apparatus is provided with: a device for rotationally driving the optical disc; a reading device for forming a light spot on the information recording surface, and receiving a reflected light to generate a read signal of the reflected light; a device for reproducing the record information and the control information from the read signal; a device for detecting whether a focus of the light spot is normal or not according to the read signal; a device for detecting whether a rotation number of the optical disc is normal or not according to the read signal; and a device for discriminating the optical disc on the basis of conditions of the detected focus and the detected rotation number.

Abstract: A junction box is provided having a housing and a cover. The housing includes a housing wall extending upwardly from a base about the periphery thereof. A lip extends outwardly about the top edge of the housing wall and engages in a snap fit in a channel in a wall of the cover. A pair of inner walls which depend from the cover top prevent the housing from inadvertently being disengaged.

Abstract: A concrete composition which has superior fluidity and filling property and from which a concrete structure having high quality and durability and being excellent in resistance to freezing and thawing can be made without compaction by vibration. The composition comprises cement, water, aggregate, at least one admixture selected from the group consisting of a water reducing agent, an air entraining agent, an air entraining water reducing agent and a superplasticizer, and at least one viscosity improver of a cellulose type of viscosity improver having a low foaming property which shows specific viscosity and an acrylic type of viscosity improver having a low viscosity which shows specific viscosity in a specified amount.

Abstract: A method of recording information on a video disk, includes the steps of: recording a video signal on the video disk; and recording table-of-contents data to control reproduction of the recorded video signal, on a plurality of frames in a lead-in area of the video disk. The table-of-contents data has a data structure, which is completed in each of the plurality of frames and is repeatedly identical in each of the plurality of frames adjacent to each other.

Abstract: A dental filling composition comprising a polymerizable monomer and an inorganic filler, characterized in that the inorganic filler comprises (A) 20 to 80% by weight of spherical inorganic oxide particles with an average particle size of from 1.0 to 5.0 .mu.m, and (B) 80 to 20% by weight of spherical inorganic oxide particles which have a particle size range of at least 0.05 .mu.m and less than 1.0 .mu.m and at least 5% by weight of which is in a particle size range of from 0.05 to 0.2 .mu.m. The dental filling composition may have a high content of the inorganic filler and, upon curing, has good mechanical strength, good surface glass and smoothness, low water absorption, and transparency compared to that of natural teeth, in which smaller particles are sufficiently packed in interstices among larger particles, and smaller particles serve also for the good transparency.

Abstract: A screw-driving device, which can drive screws continuously one by one, comprises a casing coupled to a screwdriver, a slide member slidably moved in reciprocating movement in the casing and a mechanism for feeding a screw-holding tape by one-step pitches corresponding to the distances between the adjacent screws on the tape. The tape feeding mechanism includes a guide slot provided in the casing, and a two-arm lever pivotally connected to the slide member and pivotally moved to perform indexing of the screws to a position aligned with the screwdriver by a pin fitted into the inclined section of the guide slot. A pawl member with a pawl fitted into one of the grooves at one lateral edge of the tape is pivotally connected to the end of the other arm of the two-arm lever and is biased toward the tape by a spring. At the same time, a further pawl member entering one of the grooves at the opposite side of the tape is pivotally connected to the slide member and is biased toward the tape.