Abstract: An injection molding method including a measuring step for measuring an amount of the molding material by storing a molding material fed into a cylinder of an injection molding apparatus in a tip of the cylinder by rotation of a screw and stopping a rotation of the screw after the screw is retracted to a measurement set position by a pressure from the stored molding material itself. The measuring step comprises: setting a back pressure to be applied on the screw, to a predetermined value; setting a rotation speed of the screw to a constant rotation speed within a predetermined range; and adjusting a feeding speed of the molding material to a predetermined time so that the measuring time is controlled irrespective of the rotation speed of the screw and the back pressure set value.

Abstract: A clad is produced by polymerizing methyl methacrylate and (meth)acrylic acid ester having alicyclic hydrocarbon group. A core is produced by an interfacial-gel-polymerization method. A first covering layer having a thickness being less than 500 ?m is formed on an outer surface of the clad to produce a single-fiber optical cable. A plurality of the single-fiber optical cables are bundled. A gap between the single-fiber optical cables is infused with a filler. The bundled single-fiber optical cables are covered with a second covering layer to produce a multi-fiber optical cable. Since the covering layer is thin, the multi-fiber optical cable has excellent flexibility and reduced bending loss.

Abstract: A perform formed of polymer is constructed of a center rod, first-sixth core tubes and a clad tubes, which are coaxially disposed in this order such that the refractive index may become lower gradually. Between the neighboring tubes and rod are formed gaps, and the atmospheres in the gaps are sucked. As the melt-drawing is made in the suction, the tubes and the rods adequately contacts to each other, and impurities generated in the melt-drawing are removed.

Abstract: A clad is produced by polymerizing methyl methacrylate and (meth)acrylic acid ester having alicyclic hydrocarbon group. A core is produced by an interfacial-gel-polymerization method. A first covering layer having a thickness being less than 500 &mgr;m is formed on an outer surface of the clad to produce a single-fiber optical cable. A plurality of the single-fiber optical cables are bundled. A gap between the single-fiber optical cables is infused with a filler. The bundled single-fiber optical cables are covered with a second covering layer to produce a multi-fiber optical cable. Since the covering layer is thin, the multi-fiber optical cable has excellent flexibility and reduced bending loss.

Abstract: There is disclosed a single crystalline fibrous superconductive composition represented by the atomic compositional formula: Bi.sub.2 Sr.sub.2 CaCu.sub.2 M.sub.X O.sub.Y wherein 0<X<0.5; 7.8<Y<8.5; and M is at least one member selected from the group consisting of Pb, Sn, Sb, In, Cd, Ga, Ge, K, Li, and Na. This composition is prepared by a process comprising the step of mixing source material with one another to prepare a mixture having an atomic compositional ratio: Bi=1.00, Sr=0.5.about.2.0, Ca=0.5.about.5.0, Cu=1.0.about.7.0, and M=0.1.about.1.0, wherein M is at least one member selected from the group consisting of Pb, Sn, Sb, In, Cd, Ga, Ge, K, Li, and Na, the step of melting the mixture to prepare a molten material having an atomic compositional ratio: Bi=1.00, Sr=0.5.about.2.0, Ca=0.5.about.5.0, Cu=1.0.about.7.0, M=0.1.about.1.0, and O=3.5.about.8.

Abstract: A process for producing a fibrous crystal or single crystal of a superconductor comprising bismuth, strontium, calcium, copper, lead and oxygen, having an atomic composition ratio represented by the formula Bi.sub.2-x Pb.sub.x Sr.sub.1.9-2.1 Ca.sub.1.9-2.1 Cu.sub.3 o.sub.y wherein 0<.times.<0.4 and 10.0<y<11.0, and having a Bi.sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.10 structure (2223 structure).