Abstract: An objective optical system includes: a first lens group having a negative power; an aperture stop; and a second lens group having a positive power, provided in this order from an object side. The first lens group includes a first lens, which is a negative single lens, and a cemented lens formed by a positive lens and a negative lens, provided in this order from the object side. The second lens group includes a fourth lens, which is a positive single lens, and a cemented lens formed by a positive lens and a negative lens, provided in this order from the object side. The objective optical system simultaneously satisfies Conditional Formulae (1) ?1.5<f123/f<?0.5 and (2) 1.8<f456/f<2.1, wherein f is the focal length of the entire system, f123 is the combined focal system of the first lens group, and f456 is the combined focal length of the second lens group.

Abstract: An objective optical system includes: a negative first lens group; an aperture stop; and a positive second lens group, provided in this order from an object side. The first lens group includes a first lens, which is a negative single lens, and a cemented lens formed by cementing a positive lens and a negative lens together, provided in this order from the object side. The second lens group includes a fourth lens, which is a positive single lens, and a cemented lens formed by cementing a positive lens and a negative lens together, provided in this order from the object side. The objective optical system satisfies Conditional Formula (1): f1/f<1.1, wherein f1 is the focal length of the lens provided most toward the object side, and f is the focal length of the entire lens system.

Abstract: An imaging lens consists of seven lenses of a first lens that has positive refractive power in the vicinity of an optical axis and a convex surface facing an object side in the vicinity of the optical axis, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens having a concave surface facing an image side in the vicinity of the optical axis, and at least one of the surfaces of which includes an inflection point, and both of the surfaces of which are aspherical, which are in this order from the object side. Further, each of the first lens through the seventh lens is a single lens.

Abstract: An imaging lens substantially consists of a negative first lens group and a positive second lens group in this order from the object side. The first lens group substantially consists of only a first lens, which is one biconcave lens. The second lens group substantially consists of, in the following order from the object side: a cemented lens, which is formed by bonding a second lens, i.e., a biconvex lens, and a third lens, i.e., a negative meniscus lens, in this order from the object side, and which has a positive refractive power as a whole; an aperture stop; and a cemented lens that is formed by bonding a fourth lens, i.e., a biconvex lens and a fifth lens, i.e., a negative meniscus lens in this order from the object side and that has a positive refractive power as a whole.

Abstract: An imaging lens substantially consists of a negative first lens group and a positive second lens group in this order from the object side. The first lens group substantially consists of merely a first lens, which is one negative lens. The second lens group substantially consists of, in the following order from the object side: a cemented lens, which is formed by bonding a positive lens, and a negative lens, in this order from the object side, and which has a positive refractive power as a whole; an aperture stop; a positive lens; and a negative lens. The imaging lens is configured to satisfy the conditional expression (1a): ?2.3<f1/fg2<?0.45, where f1 represents the focal length of the first lens, and fg2 represents the focal length of the second lens group.

Abstract: An imaging lens substantially consists of a negative first lens group and a positive second lens group in this order from the object side. The first lens group substantially consists of only a first lens, which is one biconcave lens. The second lens group substantially consists of, in the following order from the object side: a cemented lens, which is formed by bonding a positive lens and a negative lens, in this order from the object side, and which has a positive refractive power as a whole; an aperture stop; a positive lens; and a negative lens. The imaging lens is configured to satisfy the conditional expressions (1a): 0<f23/f<2.5 and (2a): 0<f45/f<6 at the same time.

Abstract: An imaging lens provided with a negative first lens group and a positive second lens group arranged in order from the object side. The first lens group is composed of a first group first lens which is a negative single lens, and the second lens group is composed of a positive second group first lens, a positive second group second lens, and a negative second group third lens arranged in order from the object side. The second group first lens is a biconvex lens, the second group second lens is a biconvex lens, the second group third lens is a meniscus lens, an aperture stop is disposed between the second group first and second lenses, and the second group second and third lenses form a cemented lens. The imaging lens satisfies conditional expressions (1): ?0.89?f1/f<0 and (4): 0.3<dt1/f<0.8.

Abstract: An imaging lens provided with a negative first lens group and a positive second lens group arranged in order from the object side. The first lens group is composed of a first group first lens which is a biconcave negative single lens, and the second lens group is composed of a positive second group first lens, an aperture stop, a positive second group second lens, and a negative second group third lens arranged in order from the object side, in which the second group second lens and the second group third lens are cemented together to form a cemented lens. When f1 and f2 are taken as the focal lengths of the first group first lens and the second group first lens respectively, the imaging lens satisfies a conditional expression (4a?): 0.62<|f1/f2|<0.82.

Abstract: An imaging lens provided with a negative lens group and a positive second lens group disposed in order from the object side. The first lens group is composed of a first group first lens which is a negative single lens, and the second lens group is composed of a positive second group first lens, a positive second group second lens, and a negative second group third lens disposed in order from the object side in which an aperture stop is disposed in the second lens group or the first group first lens has a biconcave shape and an aperture stop is disposed between the second group first lens and the second group second lens.

Abstract: An imaging lens provided with a negative first lens group and a positive second lens group disposed in order from the object side. The first lens group is composed of a first group first lens which is a negative biconcave single lens, and the second lens group is composed of a positive second group first lens, an aperture stop, a positive second group second lens, and a negative second group third lens disposed in order from the object side. The second group second lens and second group third lens are cemented together to form a cemented lens. The imaging lens is configured to satisfy a conditional expression (3) 0.9<dt3/f<1.3, and further configured to satisfy conditional expression (1) 31<?d2<55 or (1?): 35<?d2 and a conditional expression (2): ?10<?d1??d2<25.

Abstract: An imaging lens provided with a negative first lens group and a positive second lens group disposed in order from the object side. The first lens group is composed of a first group first lens which is a biconcave negative single lens, and the second lens group is composed of a positive second group first lens, an aperture stop, a positive second group second lens, and a negative second group third lens disposed in order from the object side. The second group second lens and second group third lens are cemented to form a cemented lens. The imaging lens is configured to satisfy conditional expressions (2): 0<fg2/f<1.3, (2b?): 0.5<fg2/f<1.25, and (6): 31<?d2<70 at the same time, where fg2 is combined focal length of the second lens group, f is focal length of the entire lens system, and ?d2 is Abbe number of the second group first lens.

Abstract: An art of hydrogen concentration measurement in which the hydrogen concentration of any given location of an object to be measured can be nondestructively obtained is provided.

Abstract: A resin composition characterized as containing (A) a synthetic resin having a melting temperature of 300° C. or above and (B) a platy inorganic filler incorporated in the resin and having the following properties; pH of aqueous dispersion: 5.5-8.0, amount of extracted alkalis: Na 30 ppm or below and K 40 ppm or below, maximum diameter a: 50 ?m or below, thickness b: 1.0 ?m or below, and aspect ratio (a/b): 20 or above.

Abstract: A resin composition characterized as containing (A) a synthetic resin having a melting temperature of 300° C. or above and (B) a platy inorganic filler incorporated in the resin and having the following properties; pH of aqueous dispersion: 5.5-6.0, amount of extracted alkalis: Na 30 ppm or below and K 40 ppm or below, maximum diameter a: 50 ?m or below, thickness b: 1.0 ?m or below, and aspect ratio (a/b): 20 or above.

Abstract: An art of hydrogen concentration measurement in which the hydrogen concentration of any given location of an object to be measured can be nondestructively obtained is provided.

Abstract: A channel fastener, which is capable of preventing or suppressing the plastic deformation of a leaf spring when the other device such as a fuel assembly and a tool is brought into contact therewith from the upper side, is provided. The channel fastener (6) comprises a leaf spring guard (9) having a leg body (13) formed in a roughly L-shape in horizontal cross section and extending vertically and a flat upper plate (12) connected to the leg body (13) at the upper end of the leg body (13) and extending horizontally, and a leaf spring (8) having an upper plate part (15) fixed to the leaf spring guard flat upper plate (12) and extending along the leaf spring guard flat upper plate (12) and at least two legs (17) connected to the upper plate part (15) and extending downward along the leaf spring guard leg body (13). One or a plurality of projected parts (21) projected upward are formed on the leaf spring guard fiat upper plate (12).

Abstract: A resin composition characterized as containing (A) a synthetic resin having a melting temperature of 300° C. or above and (B) a platy inorganic filler incorporated in the resin and having the following properties; pH of aqueous dispersion: 5.5-8.0, amount of extracted alkalis: Na 30 ppm or below and K 40 ppm or below, maximum diameter a: 50 ?m or below, thickness b: 1.0 ?m or below, and aspect ratio (a/b): 20 or above.

Abstract: A resin composition characterized as containing (A) a synthetic resin having a melting temperature of 300° C. or above and (B) a platy inorganic filler incorporated in the resin and having the following properties; pH of aqueous dispersion: 5.5-8.0, amount of extracted alkalis: Na 30 ppm or below and K 40 ppm or below, maximum diameter a: 50 ?m or below, thickness b: 1.0 ?m or below, and aspect ratio (a/b): 20 or above.

Abstract: The present invention provides a resin composition comprising (A) at least one heat-resistant thermoplastic resin selected from the group consisting of a polyketone resin, a polyimide resin, polyethernitrile, polybenzimidazole, polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, a liquid crystal polyester resin, and 1,4-polyphenylene, and (B) a flaky inorganic filler that: (1) has a Mohs hardness of 3.0 or lower, (2) has a coefficient of linear expansion not higher than 5.0×10−5/K, (3) is chemically inert and retains a layer structure to at least 500° C., and (4) has an aspect ratio (the average particle diameter/thickness ratio) of 10 or higher; a formed article thereof; and a substrate film for printed circuit boards as use thereof.

Abstract: A resin composition characterized as containing (A) a synthetic resin having a melting temperature of 300° C.