Abstract: Joint parts of joinable plates to be joined to each other are joined by a plurality of joining bolts. The joining bolts are arranged in a direction of a tensile load F. The joint parts of the plate members have four sections T1 to T4 that vary in elastic modulus. The elastic modulus (E1 to E4) of these sections T1 to T4 have a relationship of E1(T1)>E2(T2)>E3(T3)>E4(T4).

Abstract: A bridge fiber includes a core layer and an outer layer which has an index of refraction higher than that of the core layer and covers the outer peripheral surface of the core layer. The outer layer is surrounded by a substance such as the atmosphere having an index of refraction lower than an index of refraction n2 of the outer layer. An area AR1 of the outer layer at one end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of each of a plurality of pumping light inputting optical fibers, while an area AR2 of the core layer at another end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of an amplification optical fiber.

Abstract: An optical fiber propagates a light beam at a predetermined wavelength at least in an LP01 mode and an LP02 mode. A dopant that changes a Young's modulus is doped to at least a part of a waveguide region 12a of a cladding 12 through which a light beam at a predetermined wavelength is propagated and to a region 11b in a core 11 in which the intensity of the light beam in the LP01 mode is greater than the intensity of the light beam in the LP02 mode. At least a part of the Young's modulus in the waveguide region 12a of the cladding 12 is smaller than a Young's modulus in the region 11b in the core 11 in which the intensity of the light beam in the LP01 mode is greater than the intensity of the light beam in the LP02 mode.

Abstract: An optical fiber 10 propagates a light beam at a predetermined wavelength at least in an LP01 mode and an LP02 mode. In regions 11a and 11c in which the intensity of a light beam in the LP02 mode is greater than the intensity of a light beam in the LP01 mode, at least a part of a Young's modulus in the region 11c on the circumferential side of the region 11b in the core in which the intensity of the light beam in the LP01 mode is greater than the intensity of the light beam in the LP02 mode is smaller than a Young's modulus in the region 11b in which the intensity of the light beam in the LP01 mode is greater than the intensity of the light beam in the LP02 mode.

Abstract: A bridge fiber includes a core layer 31 and an outer layer 32 which has an index of refraction higher than that of the core layer 31 and covers the outer peripheral surface of the core layer 31. The outer layer 32 is surrounded by a substance such as the atmosphere having an index of refraction lower than an index of refraction n2 of the outer layer 32. An area AR1 of the outer layer 32 at one end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of each of a plurality of pumping light inputting optical fibers, while an area AR2 of the core layer 31 at another end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of an amplification optical fiber 40.

Abstract: joint structure for a composite member having a light-weight and low-cost structure, easy to manufacture, and resistible against a large shear load, is provided. A joint structure (1) for a composite member made from a composite material, comprising a plate for increasing thickness (40a, 40b) adhered to at least one side of the composite member (10); wherein the composite member (10) and a counterpart member (20) are fastened together by inserting and fixing a fastener member (30) into a through-hole (24, 26) formed through the composite member (10), the plate for increasing thickness (40a, 40b), and the counterpart member (20) to be joined to the composite member.

Abstract: A composite structure (3) formed of a composite member which extends in one direction, includes holes (5), and is made of fiber reinforced plastics. A tensile load and/or a compressive load are applied to the composite structure (3) in the one direction. Tensile stiffness and/or compression stiffness of peripheral areas (3a) of the holes (5) is lower than tensile stiffness and/or compression stiffness of the other area (3b), which surrounds the peripheral areas (3a), in the one direction, and the width of the peripheral area (3a) in a direction orthogonal to the one direction is set to 1.1 times or less of the diameter of the hole (5) in the direction orthogonal to the one direction.

Abstract: A bridge fiber includes a core layer 31 and an outer layer 32 which has an index of refraction higher than that of the core layer 31 and covers the outer peripheral surface of the core layer 31. The outer layer 32 is surrounded by a substance such as the atmosphere having an index of refraction lower than an index of refraction n2 of the outer layer 32. An area AR1 of the outer layer 32 at one end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of each of a plurality of pumping light inputting optical fibers, while an area AR2 of the core layer 31 at another end face of the bridge fiber is an area that is to be optically coupled to an end face of a core of an amplification optical fiber 40.

Abstract: An amplification optical fiber includes a core and a clad which covers the core. The core propagates light having a predetermined wavelength in at least an LP01 mode, an LP02 mode, and LP03 mode and, in the core, when the LP01 mode, the LP02 mode, and the LP03 mode are standardized by a power, in at least a part of a region where an intensity of at least one of the LP02mode and the LP03 mode is stronger than an intensity of the LP01 mode, an active element which stimulates and emits light having a predetermined wavelength is added with a higher concentration than that in at least a part of a region where the intensity of the LP01 mode is stronger than the intensities of the LP02 mode and the LP03 mode.

Abstract: A lightning-protection fastener is provided that is capable of reliably preventing peeling off of an insulation layer during the operation of an aircraft and improving the anti-lightning-strike capability and reliability. There is a lightning-protection fastener that fastens a skin of an aircraft and a structural member positioned inside the skin, in which an insulation layer is melt adhered so as to cover one end surface of a head portion and also to mechanically engage with a fastener-side engagement portion (engagement portion) formed on the end surface.

Abstract: An amplification optical fiber includes a core and a clad which covers the core. The core propagates light having a predetermined wavelength in at least an LP01 mode, an LP02 mode, and LP03 mode and, in the core, when the LP01 mode, the LP02 mode, and the LP03 mode are standardized by a power, in at least a part of a region where an intensity of at least one of the LP02 mode and the LP03 mode is stronger than an intensity of the LP01 mode, an active element which stimulates and emits light having a predetermined wavelength is added with a higher concentration than that in at least a part of a region where the intensity of the LP01 mode is stronger than the intensities of the LP02 mode and the LP03 mode.

Abstract: An absorbent article package is individually packaged by folding a packaging sheet and an absorbent article in a state where the absorbent article is arranged on the packaging sheet. In a state where the individually-packaged absorbent article is opened, in the packaging sheet and the absorbent article, a first folding line based on which the absorbent article and the packaging sheet are folded towards the topsheet side, and a second folding line based on which the absorbent article and the packaging sheet are folded towards the backsheet side are formed adjacent to each other in the longitudinal direction.

Abstract: Joint parts 14 of joinable plates 12a, 12b to be joined to each other are joined by a plurality of joining bolts 16a-16d. The joining bolts are arranged in a direction of a tensile load F. The joint parts 14 of the plate members 12a, 12b have four sections T1 to T4 that vary in elastic modulus. The elastic modulus (E1 to E4) of these sections T1 to T4 have a relationship of E1(T1)>E2(T2)>E3(T3)>E4(T4). By arranging the bolts 36a, 36d in the low-elastic sections T1, T4, the shared load of the joining bolts are equalized.

Abstract: A composite material structure that can be made lighter in weight is provided, with the stress concentration at peripheral edge regions around holes being taken into consideration. A wing (1) that is a composite material structure is of a composite material that extends in one direction, has access holes (5) formed therein, and is made of fiber reinforced plastic. A lower surface outer plate (3) of the wing (1) is subjected to a tensile load in the longitudinal direction. The longitudinal tensile stiffness of peripheral edge regions (3a) around the access holes (5) is lower than the longitudinal tensile stiffness of other regions (3b) surrounding the peripheral edge regions (3a).

Abstract: There are provided an amplification optical fiber, and an optical fiber amplifier and a resonator using the same capable of outputting light of high beam quality even when a higher-order mode that is axially symmetric is excited in addition to LP01 mode. An amplification optical fiber 50 includes: a core 51; a clad 52 coating the core 51; and an outer clad 53 coating the clad 52, wherein the core 51 has a larger refractive index than the clad 52, the core 51 allows light having a predetermined wavelength to propagate in at least LP01 mode and LP02 mode, and in the core 51, active element that stimulates to emit light of the predetermined wavelength is doped at a higher concentration at a position where an intensity of the LP02 mode becomes zero than center of the core 51.

Abstract: The invention provides an amplification optical fiber, which can output light with a good beam quality even when a higher-order mode is excited, and an optical fiber amplifier using the amplification optical fiber. An amplification optical fiber 50 has a core 51 and a clad 52 covering the core 51. The core 51 propagates light with a predetermined wavelength in at least an LP01 mode, and an LP02 mode, and an LP03 mode. When the LP01 mode, the LP02 mode, and the LP03 mode are standardized by power, in at least a part of a region where the intensity of the LP01 mode is larger than at least one of the intensities of the LP02 mode and the LP03 mode, the active element is added to the core 51 at a higher concentration than the central portion of the core.

Abstract: While a protection sheet 60 is disposed on a non-skin-surface 20a of an absorbent article 1, part of the protection sheet 60 is folded back in such a manner as to reach a position where the part overlaps other part, which comes in contact with the non-skin surface 20a of the absorbent article 1. An end portion 60a of the protection sheet 60 is bonded, while being folded back, to the protection sheet 60 by means of an adhesive material 70. Edge portions 60b and 60c on both sides of the protection sheet 60 in a longitudinal direction of the protection sheet 60 are bonded together through thermal fusion bonding while being folded. A second adhesive region 71 coated with the adhesive material 70 is formed in a predetermined position which faces the non-skin-surface 20a of a backsheet 20. The second adhesive region 71 is formed at a position corresponding to a non-adhesive region 52.

Abstract: The invention provides an amplification optical fiber, which can output light with a good beam quality even when a higher-order mode is excited, and an optical fiber amplifier using the amplification optical fiber. An amplification optical fiber 50 has a core 51 and a clad 52 covering the core 51. The core 51 propagates light with a predetermined wavelength in at least an LP01 mode, and an LP02 mode, and an LP03 mode. When the LP01 mode, the LP02 mode, and the LP03 mode are standardized by power, in at least a part of a region where the intensity of the LP01 mode is larger than at least one of the intensities of the LP02 mode and the LP03 mode, the active element is added to the core 51 at a higher concentration than the central portion of the core.

Abstract: A fiber laser light source is provided with a laser resonator including a pair of fiber gratings optically connected to a fiber in a state that the fiber is interposed between the paired fiber gratings. The reflection center wavelength of a laser-exit side fiber grating, out of the paired fiber gratings, lies in a wavelength range where the reflectance of a fiber grating, out of the paired fiber gratings, closer to the pump laser light source is not smaller than 80% but not larger than 98%.

Abstract: There are provided an amplification optical fiber, and an optical fiber amplifier and a resonator using the same capable of outputting light of high beam quality even when a higher-order mode that is axially symmetric is excited in addition to LP01 mode. An amplification optical fiber 50 includes: a core 51; a clad 52 coating the core 51; and an outer clad 53 coating the clad 52, wherein the core 51 has a larger refractive index than the clad 52, the core 51 allows light having a predetermined wavelength to propagate in at least LP01 mode and LP02 mode, and in the core 51, active element that stimulates to emit light of the predetermined wavelength is doped at a higher concentration at a position where an intensity of the LP02 mode becomes zero than center of the core 51.