Abstract: A method of producing an optical waveguide grating by exposure to light. An optical waveguide having a core composed of a material wherein the refractive index changes due to exposure to UV light is formed into an optical waveguide grating by applying a grating portion formation step wherein a grating portion is formed by irradiation with UV light at a predetermined spacing, and an overall exposure step after formation of the grating portion wherein the entire grating portion is irradiated with UV light. As a result, the effective refractive index of the grating portion is changed so as to allow the central wavelength to be adjusted without changing the rejection. Consequently, the grating properties can be precisely and easily controlled.

Abstract: The present invention is related to an dispersion compensating optical fiber technology, comprising a central core, a middle part with a refractive index lower than this central core, and a cladding with a refractive index higher than said middle part and lower than said central core, characterized in: an outer diameter of said middle part being 2.5.about.3.5 times an outer diameter of said central core; a relative refractive index difference of said cladding to said middle part being -0.08.about.-0.2% with the refractive index of the cladding being zero; and having substantially single-mode transmission in the wavelength 1.55 .mu.m band, the chromatic dispersion being -80 ps/nm/km or less, the dispersion slope being +0.08 ps/nm.sup.2 /km or less, and the bending loss being 1.0 dB/m or less.

Abstract: An optical waveguide grating with radiative mode-coupling properties, with exceptional stability and reliability as an optical component, wherein the central wavelength of the rejection band has a low temperature dependence, due to the use of silica glass doped with germanium and boron for the core. The rejection bandwidth can be narrowed without increasing the grating length by forming the radiative mode-coupled optical waveguide grating in an optical waveguide wherein the mean relative refractive index difference of the core is greater than that of optical communication waveguides.

Abstract: Core comprises a main stem which is formed on a substrate, linearly extending in the beam propagating direction and short branches with a certain length which extend perpendicularly to the beam propagating direction toward both sides along the plane of the substrate and are arranged at regular intervals in the beam propagating direction. Thus, the branches are arranged in a ladder geometry when it is viewed from the top, forming a rectangular waveform arrangement. The core constitutes a grating structure in which the width of the core is made to vary periodically with the branches in the beam propagating direction.

Abstract: The present invention provides a poly-amino acidic oligonucleotide-carrier comprising a poly-lysine:serine random copolymer.This carrier is bonded with oligonucleotide without causing precipitation, and smoothly releases the bonded oligonucleotide within cells. It is therefore useful as an in vivo transport carrier of an oligonucleotide drug against various genetic diseases and viral diseases such as AIDS. It also makes a great contribution to creation of various useful animals and plants by genetic engineering technique, including virus-resistant plants.

Abstract: An electrode for a vacuum circuit breaker provided with a connecting portion made of a material having the same resistivity as the arc running face portions across the corresponding arc guiding channel at the outer circumferential end thereof, wherein when the outer diameter of the connecting portion is D.sub.1 and the inner diameter of the connecting portion is D.sub.2, the width of the connecting portion is designed so that the ratio D.sub.2 /D.sub.1 is in a range of more than 0.9 and less than 1.0. An arc generated between the electrodes is magnetically driven over the arc running face portions via the connecting portion so that the current interrupting capacity of the electrode is increased and the size and weight of the electrode are reduced.

Abstract: The present invention relates to an optical fiber filter provided with a portion which selectively reflects or transmits light of a specific wavelength, this portion comprised of a multimode optical fiber in which the refractive index of the core changes periodically along the longitudinal direction thereof. Furthermore, this multimode optical fiber has an input end and an output end, with at least the input end of the multimode optical fiber being connected to a single mode optical fiber. As a result of forming an optical fiber filter in this way, it is possible to realize an optical fiber filter that exhibits no transmission loss at wavelengths other than the center wavelength.

Abstract: A manufacturing method for erbium doped silica, having a soot formation process, in which a silica glass soot is deposited on a seed rod for forming a soot preform in a porous state on the seed rod, a dopant impregnation process, wherein the soot preform is impregnated with at least an erbium compound, and a preform formation process, wherein this soot preform impregnated with a dopant is heated and rendered transparent. The dopant impregnation process is provided with an operation in which the soot preform obtained in the soot formation process is dipped in a solution containing an erbium compound, an aluminum compound, and a phosphorus compound; this is then desiccated, and soot preform which is impregnated with the erbium compound, the aluminum compound, and the phosphorus compound is obtained.

Abstract: A device for digital convergence correction of raster distortion correction of a picture displayed on a screen of a display device using a cathode-ray tube, in which scanning lines include a first class of scanning lines, called correction scanning lines, on which correction points are positioned, and a second class of scanning lines, called interpolated scanning lines between the correction scanning lines. The correction points are positioned at intersections of the correction scanning lines and vertical lines. The correction data for the interpolated scanning lines are produced by vertical interpolation from the correction data of a certain number of vertically aligned correction points. Convergence adjustment, however, may be conducted for only part of the correction points, and the correction data of the remaining correction points may be obtained by interpolation.

Abstract: A manufacturing method for erbium doped silica, having a soot formation process, in which a silica glass soot is deposited on a seed rod for forming a soot preform in a porous state on the seed rod, a dopant impregnation process, wherein the soot preform is impregnated with at least an erbium compound, and a preform formation process, wherein this soot preform impregnated with a dopant is heated and rendered transparent. The dopant impregnation process is provided with an operation in which the soot preform obtained in the soot formation process is dipped in a solution containing an erbium compound, an aluminum compound, and a phosphorus compound; this is then desiccated, and soot preform which is impregnated with the erbium compound, the aluminum compound, and the phosphorus compound is obtained.

Abstract: The present invention relates to a method for the fusion splicing of carbon coated optical fibers and to a method for providing reinforced performance of the spliced points. Concretely, carbon coated optical fibers are fusion spliced in an atmosphere containing less than 0.5 vol % of oxygen without the removal of the carbon coating. In order to minimize the amount of damage to the carbon coating resulting from the fusion, the decline in the failure probability of the optical fiber is controlled by means of applying moisture to the spliced part or by means of the adhesion of the oxidized carbon gases to the optical fiber. On the other hand, the carbon coating layer which was removed by oxidation at the time of the fusion splicing is recoated by means of a CVD reaction using a laser as a heat source. By means of this, the decline in the fatigue characteristics of the spliced part can be controlled.

Abstract: The present invention is directed to an optical fiber comprising a core and a cladding layer wherein at least one of the constitutional parameters thereof changes along the longitudinal direction of the optical fiber. In order to present a useful optical fiber wherein the occurrence of a Brillouin scattering is prevented, an optical fiber having altered constitutional parameters is found to be effective. The constitutional parameters mean the parameters which determine the constitution of the optical fiber and is capable of influencing the condition of electromagnetic wave transmitting therethrough such as light or acoustic wave. The constitutional parameters include diameter of the core, index of refraction of the core, diameter of the optical fiber, composition of the glass, residual stress of the core. Some examples are disclosed about their manufacturing process and the test results. Much improvement was measured, especially in the use for a single mode optical fiber.

Abstract: The present invention relates to a method for the fusion splicing of carbon coated optical fibers and to a method for providing reinforced performance of the spliced points. Concretely, carbon coated optical fibers are fusion spliced in an atmosphere containing less than 0.5 vol % of oxygen without the removal of the carbon coating. In order to minimize the amount of damage to the carbon coating resulting from the fusion, the decline in the failure probability of the optical fiber is controlled by means of applying moisture to the spliced part or by means of the adhesion of the oxidized carbon gases to the optical fiber. On the other hand, the carbon coating layer which was removed by oxidation at the time of the fusion splicing is recoated by means of a CVD reaction using a laser as a heat source. By means of this, the decline in the fatigue characteristics of the spliced part can be controlled.

Abstract: A friction member, such as a brake lining, disk pad or clutch facing, may be molded using a method in which the mold for the member is vibrated at a frequency and with amplitudes that are selected to imbue the friction member with desired physical properties, such as a predetermined specific gravity and porosity. The materials forming the friction member may be placed in a mold and the pressure on the mold increased and relaxed a predetermined number of times. Each time the pressure on the mold is increased, the mold is vibrated at the desired frequency and with the desired amplitude to achieve the desired physical properties. Upon completeion of the periodic vibration of the mold, the material in the mold may be subjected to a predetermined rated pressure for a predetermined period of time without vibration.

Abstract: A metal vapor laser has a discharge tube with electrodes at opposite ends. A power source is electronically connected to the electrodes and generates a discharge in a discharge region within the discharge tube. The discharge generates laser light which emerges from the tube via windows. In order to cool the apparatus, the discharge tube is surrounded by a cooling jacket in the form of a hollow cooling vessel. A liquid flows in the cooling vessel and removes heat. The space between the cooling vessel and the discharge tube is evacuated. The cooling vessel is conductive and, since it is connected between one of the electrodes and the power supply, its inner and outer walls provide two potential paths for return current. The fact that the inner and outer walls have different diameters means that the inductance of the return paths is large. Therefore, the outer wall has a gap in it filled with insulating material.

Abstract: A novel pyrazinoxide compound of NF-1616-904 having the formula (1), ##STR1## prepared by hydrolyzing the intermediate compound of NF-1616-902 which is separated from a culture broth of a microorganism belonging to the genus Thielavia.The pyazinoxide compound of NF-1616-904 possess biological and pharmacological activities, and is useful agent for preventing and treating diseases caused by superoxide radicals (O.sub.2.sup.-), and nephritis.

Abstract: An optical information recording and reporducing apparatus for recording and reproducing information optically against recording material, includes means for generating a first light beam for reproducing and erasing information which is previously recorded in the recording material, and means for providing a second light beam for recording new information into the recording material, and irradiation of the first light beam and the second light beam to an arbitrary point on the recording material is conducted in the above-mentioned order.

Abstract: A metallic vapor laser apparatus includes a cylindrical discharge tube (31) having an internal space (2), a heat-insulating material (6) encompassing the periphery of the discharge tube (31), and two electrodes (3a) and (3b) having a cylindrical portion coaxial with the discharge tube (31) and disposed at both ends of the discharge tube (31). The internal space (2) are filled with a gas containing the vapor of copper as a laser medium for effecting laser oscillation by the excitation of the filler gas and the discharge.

Abstract: A noise cancelling circuit includes a delay circuit for delaying an input signal which is supplied to an input terminal, and a signal processing circuit responsive to the input signal and an output signal from the delay circuit, to generate an output signal corresponding to the input signal. The signal processing circuit has a first switching circuit, which includes first and second switching elements connected in series between a first power supply terminal and an output, and a second switching circuit, which includes third and fourth switching elements connected in series between a second power supply terminal and the output, wherein the first and third switching elements are responsive to the aforementioned input signal, by which they are set in mutually opposite conduction states, and the second and fourth switching elements are responsive to the output signal of the delay circuit, by which they too are set in mutually opposite conduction states.

Abstract: Disclosed is a vacuum switch having a container and a pair of contact electrodes, and a method of manufacturing the same, in which at least one of the contact electrodes is constituted by a member made up of a skeleton containing cobalt as its principal component with pores into which a copper alloy containing copper as its principal component, silver, and a low melting point and high vapor pressure element having substantially no or very low solid-solubility with respect to the copper at a room temperature is impregnated.