Abstract: In a continuous casting apparatus having a pair of moving mold walls between which is defined a molten metal reservoir, the surface of molten metal is covered with an insulating member disposed within the molten metal reservoir. Projecting from opposite sides of the insulating member at locations adjacent the moving mold walls and toward the direction of movement of the mold walls are immersion walls which are immersed into the molten metal. The horizontal distance between the surface of each immersion wall and the surface of the moving mold wall closer thereto is more than 3 mm but not more than 10 mm. The molten metal within the gap between the moving mold wall and the immersion wall steadily flows outward following the movement of the mold wall, and accordingly fresh molten metal flows into the gap and circulates within the gap without stagnation. Therefore, even if slag flows into the gap, the slag positively flows outward without becoming accummulated therein.

Abstract: Method and apparatus for sealing molten metal for use in twin-roll type continuous casting apparatus for preventing molten metal from entry into a clearance between a pair of mold rolls and side weirs disposed at opposite ends of the pair of mold rolls to define a molten metal reservoir above the gap between the mold rolls. a sealing medium is supplied at the inner side of the side weirs in the vicinity of the border between the molten metal and each of the mold rolls. Entry of molten metal into the clearance is prevented without the necessity of pressing the side weirs against the roll ends.

Abstract: The present invention provides a protective cover for a surface of molten steel used in a continuous casting apparatus provided with a pair of movable mold walls arranged in parallel to each other and a melt receiver formed between said movable mold walls, for example a twin-roll type casting apparatus, said protective cover comprising a central heat insulator capable of bringing into contact with a central portion of a surface of the molten steel other than portions close to portions where the surface of the molten steel is brought into contact with the respective movable mold walls and side heat insulators mounted on said central heat insulator, covering spaces above said portions close to the portions where the surface of the molten steel is brought into contact with the respective movable mold walls and being brought into slidable contact with the surfaces of the respective movable mold walls at pointed end portions thereof.

Abstract: Delay time variation in an optical fiber digital communication system which includes optical regenerative repeaters is measured at one of terminal ends having reference clock signal. A monitor signal which depends upon the delay time variation is provided at the farthest repeater in an area where delay time is subject to secular change by dividing reference clock signal from said terminal end, and said monitor signal is returned to the terminal end from said farthest repeater, and the terminal end compares the returned monitor signal with the divided reference signal by using a phase comparator to provide measure of delay time variation.

Abstract: A signal coupler couples more than three transmitter-receivers through optical fiber cables and at least one repeater on a bit-multiplex system, by exchanging or reallocating each time slot according to a transmission station and the related destination. The coupler has a means to release the bit-multiplexing (or demultiplex) the signals from each transmitter by deriving the control clock signals from the information signals themselves. The coupler also has a means for multiplexing the bit signals for each destination by automatically adjusting the phase relationships among the released signals (demultiplexed signals) for bit-synchronization using a delay circuit.

Abstract: An apparatus for continuously producing a thin metallic strip comprises a mold 3 adapted to receive molten metal and having an outlet opening 1a through which the molten metal under solidification is drawn out as a casting 10 for guided withdrawal movement along a predetermined path, and surface smoothing devices 5 for generally continuously impacting both opposite surfaces of the casting 10 adjacent the outlet opening of the mold.

Abstract: An apparatus for continuous casting of a thin metallic plate which includes a movable mold 2 arranged for movement in a specified direction, and a melt receiver 5 disposed on the movable mold 2 for storing molten metal in coopertion therewith, whereby molten metal within the melt receiver 5, through its contact with the surface of the movable mold 2, will be cooled and formed into a casting shell, the casting shell being drawn by the movable mold 2 in the form of a thin metallic plate, wherein at least the lower end portion of the melt receiver 5 is movable along the withdrawal path of the casting shell, and wherein a mover mechanism 7 is provided for moving the lower end portion of the melt receiver 5.

Abstract: An horizontal continuous casting apparatus comprising a tundish 3 for receiving molten metal 32, horizontally reciprocally movable oscillating nozzle 12 communicating with a nozzle opening 7a of the tundish 3, a mold 24 into which one end of the nozzle 12 is slidably inserted, and a vibrator 22 for horizontally vibrating the nozzle 12.

Abstract: An apparatus for continuously casting a thin metallic strip comprising a melt receiver 3 for receiving molten metal, a pair of rolls 4 rotatably arranged under the melt receiver 3 and opposed to each other with a predetermined clearance, rotary drive device 5 for rotating the rolls 4 to draw out the molten metal under solidification as a casting through said clearance, and supply system 11 for supplying cooling water into the interior of the rolls 4, the apparatus further comprising roll temperature sensors 9 embedded in the outer peripheral portion of each roll 4 and equiangularly spaced circumferentially thereof for detecting the surface temperature of the roll 4, a position detecting device 14 for detecting the rotational position of the roll 4, and a control unit 20 for controlling the rotary drive device 5 and the cooling water supplying system 11 in response to detection signals from the temperature sensors 9 and the position detecting device 14.

Abstract: A mount arrangement of a semiconductor laser and an optical fiber as a unitary structure. A substrate has a submount disposed thereon mounting a semiconductor laser. The laser is fixed on the submount by a fusion-welding material. A fiber submount is disposed on the substrate in the vicinity of the semiconductor laser submount. An optical fiber is fixed to the fiber submount with its optical axis coaxial with the optical axis of the output light of the semiconductor laser. The fiber submount includes a material for fixing the optical fiber and has a melting point such that it will not affect the coaxial optical alignment of the semiconductor laser and the optical fiber and the fixing between the substrate, the laser submount and between the laser submount and semiconductor laser during fabrication.

Abstract: A coupling system for the output light of a semiconductor laser, characterized in that an end portion of an optical fiber is made as a focusing lens to be coupled with the output light from an active layer of the semiconductor laser is formed so that, at least in a plane parallel to the optical axis of the output light and perpendicular to the junction plane of the semiconductor laser, the width of the end portion continuously decreases towards its tip to provide a required curvature at the tip and that the distribution of light of the semiconductor laser and that of the optical fiber and the focusing lens are matched with each other in the plane perpendicular to the junction plane of the semiconductor laser. The end portion of the optical fiber defining the focusing lens may be formed to have a fixed width in a plane parallel to the junction plane of the semiconductor laser.

Abstract: An optical switch for switching laser beams, having a transparent glass plate with a reflection film on the surface of the same has been found. When the reflection film is at the first position, the first input beam is coupled with the output beam through the transparent glass plate, while the second input beam is prevented by said reflection film. When the reflection film is at the second position, the first input beam is prevented by said reflection film, and the second input beam is coupled with the output beam through the reflection by said reflection film. Thus, according to the displacement of the transparent glass plate together with the reflection film, the input beams are switched. Due to the above operational principle, the output optical level does not decrease even during the transient time, and then, the present optical switch is utilized in an optical repeater for digital communication.

Abstract: In an optical digital communication system having a plurality of optical repeaters inserted in an optical fiber cable, and a pair of terminal stations installed at the extreme ends of the optical fiber cable, the designation of the particular repeater from the terminal station is performed by the remote control signal which has the pulse pattern with the period designated to each repeater. Each repeater may have a plurality of switches for switching lasers for improving the operational reliability of the same by the redundant technique, and the control and/or the designation of the particular switch is also performed by said remote control signal by selecting the particular period and/or the repetition numbers of the period of the pulse pattern.

Abstract: The operational reliability of a light source in an optical communication system has been increased by an improved redundant arrangement of light sources and the switching arrangement of the same. The present light source arrangement comprises a plurality of light sources each of which provides a different wavelength from one another, an electrical switch for actuating the selected one of the light sources, said electrical switch being arranged to replace the actuated light source when there is something wrong with the light source in operation, and an optical multiplexer the input of which is coupled to the outputs of the light sources, and the output of the optical multiplexer is connected to an optical fiber cable.

Abstract: A fault location system in an optical fiber transmission system, in which a plurality of optical signal regenerative repeaters are sequentially connected in cascade in an optical fiber transmission cable at predetermined intervals to transmit digital information in the form of optical signals. Each of the plurality of optical signal regenerative repeaters sends out a fault location information signal composed of an inherent pattern and a fixed pattern when a fault occurs in the corresponding repeater. The inherent pattern is uniquely assigned to the optical signal regenerative repeater from a plurality of individually distinguishable inherent patterns obtained by establishing the start bits of a pseudo-noise sequence at time positions successively delayed from one after another. The fixed pattern is necessary for indicating the time positions of the start bits.