Abstract: An optical fiber is formed from silica glass, and includes a core, a first cladding which surrounds the core and has a refractive index lower than the refractive index of the core, and a second cladding which surrounds the first cladding and has a refractive index that is lower than the refractive index of the core and higher than the refractive index of the first cladding. The second cladding is divided into an inner region that is in contact with the first cladding and an outer region which surrounds the inner region and has a thickness that is half the thickness of the second cladding or less, while being 5 ?m or more. The residual stress in at least a part of the outer region is a compressive stress.

Abstract: The optical fiber has an effective area that is greater than or equal to 110 ?m2 and less than or equal to 180 ?m2 at a wavelength of 1550 nm and a cable cut-off wavelength of less than or equal to 1530 nm. An average value of a glass outer diameter in a longitudinal direction is 125±0.5 ?m. When ? is a standard deviation of the glass outer diameter in the longitudinal direction, 3? is greater than or equal to 0.1 ?m and less than or equal to 0.5 ?m.

Abstract: An optical fiber according to an embodiment has a structure for enabling determination of improvement in transmission loss at a preform stage. The optical fiber includes: a core containing Cl and having an average refractive index lower than a refractive index of pure silica glass; a first cladding containing F; a second cladding; and a resin coating, in which an effective area at a wavelength of 1550 nm is 135 ?m2 or more and 170 ?m2 or less, a ratio of the effective area to a cutoff wavelength ?C is 85.0 ?m or more, a bending loss of an LP01 mode at a wavelength of 1550 nm and at a bending radius of R15 mm is less than 4.9 dB per 10 turns, and the resin coating includes a primary resin layer having a Young's modulus of 0.3 MPa or less.

Abstract: The optical fiber offered is capable of not only restraining the attenuation due to glass defects, but also reducing the increase of manufacturing cost. The optical fiber is made of silica glass and includes a core and a cladding. The cladding encloses the core and has a refractive index smaller than that of the core. When the core is divided into inner core and outer core at half of the radius of the core, the average chlorine concentration of the inner core is larger than that of the outer core. The core includes any of the alkali metal group.

Abstract: An optical fiber in which the increase of attenuation can be reduced is offered. An optical fiber is made of silica glass and includes a core and a cladding enclosing the core. The refractive index of the cladding is smaller than that of the core. The core includes chlorine and any of the alkali metal group, The chlorine concentration is 1 ppm or more in the whole region of the core. In the whole region of the core, the absolute value of rate of radial change of the chlorine concentration is smaller than 2000 ppm/?m.

Abstract: An optical fiber preform includes a silica-glass core portion, and a cladding portion surrounding the core portion, the cladding portion being composed of a fluorine-containing silica glass having a lower refractive index than the core portion, the core portion including a first region that does not include the central axis thereof, the first region containing a first dopant selected from sodium, potassium, and compounds thereof, and a second region that includes the central axis, the second region containing a second dopant that reduces the viscosity of the silica glass, the second dopant having a diffusion coefficient of 1×10?12 cm2/s or more and less than the first dopant at 2,000° C. to 2,300° C., in which the entire core portion has an average first dopant concentration of 10 atomic ppm or more and 2,000 atomic ppm or less and an average second dopant concentration of 10 atomic ppm or more.

Abstract: A charge transport material which can be used for an organic electronic element and contains a charge transport polymer capable of improving the element characteristics is provided, and an ink composition containing the material is also provided. Further, an organic electronic element and an organic EL element having excellent element characteristics, and a display element, an illumination device and a display device that use these elements are also provided. More specifically, an organic electronic material containing a charge transport polymer or oligomer having at least one structural unit containing a substituted or unsubstituted dibenzofuran structure or dibenzothiophene structure is provided.

Abstract: One embodiment relates to an organic electronic material containing a charge transport polymer, wherein the charge transport polymer is a polymer which, when 25 ?L portions of methanol are added dropwise and stirred into 1,000 ?L of a solution containing the charge transport polymer and toluene in a ratio of 20 mg of the charge transport polymer per 2,290 ?L of toluene, the amount of methanol added by the time cloudiness develops in the solution is greater than 350 ?L.

Abstract: An optical fiber in which the increase of attenuation can be reduced is offered. An optical fiber is made of silica glass and includes a core and a cladding enclosing the core. The refractive index of the cladding is smaller than that of the core. The core includes chlorine and any of the alkali metal group. The chlorine concentration is 1 ppm or more in the whole region of the core. In the whole region of the core, the absolute value of rate of radial change of the chlorine concentration is smaller than 2000 ppm/?m.

Abstract: The optical fiber offered is capable of not only restraining the attenuation due to glass defects, but also reducing the increase of manufacturing cost. The optical fiber is made of silica glass and includes a core and a cladding. The cladding encloses the core and has a refractive index smaller than that of the core. When the core is divided into inner core and outer core at half of the radius of the core, the average chlorine concentration of the inner core is larger than that of the outer core. The core includes any of the alkali metal group.

Abstract: Disclosed is an organic electronic material containing a polymer or oligomer having a structural unit that has hole transport properties, and also having an alkyl chain of 6 to 20 carbon atoms. Also disclosed are an ink composition, an organic layer, an organic electronic element, an organic electroluminescent element, a display element, an illumination device and a display device.

Abstract: One embodiment relates to an organic electronic material containing a charge transport polymer or oligomer having a crosslinking group represented by formula (1) shown below at least at one terminal, and also having a crosslinking group represented by formula (2) shown below at least at one terminal. In formula (1), each of Ra to Rg independently represents a hydrogen atom or a substituent. In formula (2), each of Ra to Rc independently represents a hydrogen atom or a substituent.

Abstract: Embodiments of the present invention relate to a composition containing a polymer or oligomer (A) and an initiator (B), wherein the polymer or oligomer (A) contains no alkyl groups of 5 or more carbon atoms, contains at least one type of structural unit selected from the group consisting of a structural unit containing an aromatic amine structure and a structural unit containing a carbazole structure, and contains, at one or more terminals, a structural unit containing a thienyl group which may have a substituent, and a degree of solubility of the composition is capable of being changed by applying heat, light, or both heat and light.

Abstract: Provided is an optical fiber containing an alkali metal element or the like having a smaller diffusion coefficient than K and having a low Rayleigh scattering loss. An optical fiber is composed of silica glass and includes a core and a cladding arranged to surround the core which has a lower refractive index than the core. The core includes a first core including a central axis and a second core arranged to surround the first core. The average concentration of an alkali metal element or alkaline-earth metal element in the first core is 10 mol ppm or less. The average concentration of chlorine in the first core is 2000 mol ppm or more. The average concentration of an alkali metal element or alkaline-earth metal element in the second core is 10 mol ppm or more. The average concentration of chlorine in the second core is 10 to 600 mol ppm.

Abstract: One embodiment relates to a branched polymer production method including reacting a monomer component containing at least reactive monomers (1) and (2) described below. The reactive monomer (1) has at least a conjugation unit and three or more reactive functional groups bonded to the conjugation unit, wherein the three or more reactive functional groups include two types of reactive functional groups that are mutually different. The reactive monomer (2) has at least a conjugation unit and two reactive functional groups bonded to the conjugation unit, wherein one of the two reactive functional groups is a group capable of reacting with one type of reactive functional group selected from among the two types of reactive functional groups, and the other of the two reactive functional groups is a group capable of reacting with the other type of reactive functional group selected from among the two types of reactive functional groups.

Abstract: An optical fiber in which the increase of attenuation can be reduced is offered. An optical fiber is made of silica glass and includes a core and a cladding enclosing the core. The refractive index of the cladding is smaller than that of the core. The core includes chlorine and any of the alkali metal group. The chlorine concentration is 1 ppm or more in the whole region of the core. In the whole region of the core, the absolute value of rate of radial change of the chlorine concentration is smaller than 2000 ppm/?m.

Abstract: One embodiment relates to a branched polymer production method that includes reacting a monomer component containing at least a reactive monomer (1) described below. The reactive monomer (1) has at least a conjugation unit and three or more reactive functional groups bonded to the conjugation unit, and the three or more reactive functional groups include two types of reactive functional groups that are mutually different.

Abstract: One embodiment relates to an organic electronic material containing a charge transport polymer or oligomer having a crosslinking group represented by formula (1) shown below at two or more terminal portions.

Abstract: The optical fiber offered is capable of not only restraining the attenuation due to glass defects, but also reducing the increase of manufacturing cost. The optical fiber is made of silica glass and includes a core and a cladding. The cladding encloses the core and has a refractive index smaller than that of the core. When the core is divided into inner core and outer core at half of the radius of the core, the average chlorine concentration of the inner core is larger than that of the outer core. The core includes any of the alkali metal group.

Abstract: The present embodiment relates to an optical fiber preform manufacturing method in which two or more kinds of alkali metal elements are diffused and doped to an inner surface of a glass pipe. The manufacturing method includes: a first drying step performed at a temperature equal to or lower than a lowest temperature among melting point temperatures of the alkali metal salt raw materials; and a second drying step performed at a temperature which is equal to or higher than a highest temperature among the melting point temperatures of the alkali metal salt raw materials and at which vapor pressures of the alkali metal salt raw materials are 2 mmHg or lower.