Abstract: Provided are a method for recovering gold, in which gold is recovered from a solution containing a gold cyano complex using a crosslinked resin containing a vinyl amine unit, by which gold can be efficiently recovered from the solution not only in a case (A) where a concentration of the gold cyano complex in the solution is low but also in a case (B) where another metal is dissolved in the solution; a method for recovering gold, in which the crosslinked resin and the solution are brought into contact with each other to separate the crosslinked resin and the solution from each other, by which gold can be efficiently recovered from the solution not only in the case (A) but also in the case (B); and a gold recovery facility comprising: a container inside which the crosslinked resin is accommodated in a flowable manner; and a device which feeds the solution to the container, by which gold can be efficiently recovered from the solution not only in the case (A) but also in the case (B).

Abstract: Provided are a method for recovering gold, in which gold is recovered from a solution containing a gold cyano complex using a crosslinked resin containing a vinyl amine unit, by which gold can be efficiently recovered from the solution not only in a case (A) where a concentration of the gold cyano complex in the solution is low but also in a case (B) where another metal is dissolved in the solution; a method for recovering gold, in which the crosslinked resin and the solution are brought into contact with each other to separate the crosslinked resin and the solution from each other, by which gold can be efficiently recovered from the solution not only in the case (A) but also in the case (B); and a gold recovery facility comprising: a container inside which the crosslinked resin is accommodated in a flowable manner; and a device which feeds the solution to the container, by which gold can be efficiently recovered from the solution not only in the case (A) but also in the case (B).

Abstract: An optical fiber that has a small bending loss can be securely prevented from being fractured due to accidental bending during installation or other operations. The optical fiber includes a core, a first cladding, a second cladding, and a third cladding. The relative refractive index difference ?1 of the core is in the range of 0.3% to 0.38%, the relative refractive index difference ?2 of the first cladding is equal to or smaller than 0%, and the relative refractive index difference ?3 of the second cladding is in the range of ?1.8% to ?0.5%. The inner radius r2 and the outer radius r3 of the second cladding satisfy the expression “0.4r2+10.5<r3<0.2r2+16”, and the inner radius r2 of the second cladding is equal to or greater than 8 ?m.

Abstract: An optical fiber that has a small bending loss can be securely prevented from being fractured due to accidental bending during installation or other operations. The optical fiber includes a core, a first cladding, a second cladding, and a third cladding. The relative refractive index difference ?1 of the core is in the range of 0.3% to 0.38%, the relative refractive index difference ?2 of the first cladding is equal to or smaller than 0%, and the relative refractive index difference ?3 of the second cladding is in the range of ?1.8% to ?0.5%. The inner radius r2 and the outer radius r3 of the second cladding satisfy the expression “0.4r2+10.5<r3<0.2r2+16”, and the inner radius r2 of the second cladding is equal to or greater than 8 ?m.

Abstract: An optical fiber that has a small bending loss can be securely prevented from being fractured due to accidental bending during installation or other operations, and is compliant with the G. 652 standard. The optical fiber includes a core, a first cladding, a second cladding and a third cladding. The relative refractive index difference ?1 of the core is in the range of 0.3% to 0.38%, the relative refractive index difference ?2 of the first cladding is equal to or smaller than 0%, and the relative refractive index difference ?3 of the second cladding is in the range of ?1.8% to ?0.5%. The inner radius r2 and the outer radius r3 of the second cladding satisfy the expression “0.4r2+10.5<r3<0.2r2+16”, and the inner radius r2 of the second cladding is equal to or greater than 8 ?m.

Abstract: An optical fiber that has a small bending loss can be securely prevented from being fractured due to accidental bending during installation or other operations, and is compliant with the G. 652 standard. The optical fiber includes a core, a first cladding, a second cladding and a third cladding. The relative refractive index difference ?1 of the core is in the range of 0.3% to 0.38%, the relative refractive index difference ?2 of the first cladding is equal to or smaller than 0%, and the relative refractive index difference ?3 of the second cladding is in the range of ?1.8% to ?0.5%. The inner radius r2 and the outer radius r3 of the second cladding satisfy the expression “0.4r2+10.5<r3<0.2r2+16”, and the inner radius r2 of the second cladding is equal to or greater than 8 ?m.

Abstract: Provided is an optical fiber that has a small bending loss, can be securely prevented from being fractured due to accidental bending during installation or other operations, and is compliant with the G. 652 standard. An optical fiber 1 includes a core 11, a first cladding 12, a second cladding 13, and a third cladding 14. The relative refractive index difference ?1 of the core 11 is in the range of 0.3% to 0.38%, the relative refractive index difference ?2 of the first cladding 12 is equal to or smaller than 0%, and the relative refractive index difference ?3 of the second cladding 13 is in the range of ?1.8% to ?0.5%. The inner radius r2 and the outer radius r3 of the second cladding 13 satisfy the expression “0.4r2+10.5<r3<0.2r2+16”, and the inner radius r2 of the second cladding 13 is equal to or greater than 8 ?m. The bending loss at a wavelength of 1550 nm and at a radius of curvature of 7.5 mm is smaller than 0.

Abstract: Provided is an optical fiber that has a small bending loss, can be securely prevented from being fractured due to accidental bending during installation or other operations, and is compliant with the G. 652 standard. An optical fiber 1 includes a core 11, a first cladding 12, a second cladding 13, and a third cladding 14. The relative refractive index difference ?1 of the core 11 is in the range of 0.3% to 0.38%, the relative refractive index difference ?2 of the first cladding 12 is equal to or smaller than 0%, and the relative refractive index difference ?3 of the second cladding 13 is in the range of ?1.8% to ?0.5%. The inner radius r2 and the outer radius r3 of the second cladding 13 satisfy the expression “0.4r2+10.5<r3<0.2r2+16”, and the inner radius r2 of the second cladding 13 is equal to or greater than 8 ?m. The bending loss at a wavelength of 1550 nm and at a radius of curvature of 7.5 mm is smaller than 0.

Abstract: Provided is an optical fiber that has a small bending loss, can be securely prevented from being fractured due to accidental bending during installation or other operations, and is compliant with the G. 652 standard. An optical fiber 1 includes a core 11, a first cladding 12, a second cladding 13, and a third cladding 14. The relative refractive index difference ?1 of the core 11 is in the range of 0.3% to 0.38%, the relative refractive index difference ?2 of the first cladding 12 is equal to or smaller than 0%, and the relative refractive index difference ?3 of the second cladding 13 is in the range of ?1.8% to ?0.5%. The inner radius r2 and the outer radius r3 of the second cladding 13 satisfy the expression “0.4r2+10.5<r3<0.2r2+16”, and the inner radius r2 of the second cladding 13 is equal to or greater than 8 ?m. The bending loss at a wavelength of 1550 nm and at a radius of curvature of 7.5 mm is smaller than 0.

Abstract: Provided is an optical fiber that has a small bending loss, can be securely prevented from being fractured due to accidental bending during installation or other operations, and is compliant with the G. 652 standard. An optical fiber 1 includes a core 11, a first cladding 12, a second cladding 13, and a third cladding 14. The relative refractive index difference ?1 of the core 11 is in the range of 0.3% to 0.38%, the relative refractive index difference ?2 of the first cladding 12 is equal to or smaller than 0%, and the relative refractive index difference ?3 of the second cladding 13 is in the range of ?1.8% to ?0.5%. The inner radius r2 and the outer radius r3 of the second cladding 13 satisfy the expression “0.4r2+10.5<r3<0.2r2+16”, and the inner radius r2 of the second cladding 13 is equal to or greater than 8 ?m. The bending loss at a wavelength of 1550 nm and at a radius of curvature of 7.5 mm is smaller than 0.