Abstract: A production method of carbon dioxide fixing sludge fine powder as a low-carbon binder. Water is added to residual concrete or returned concrete to form it into a slurry, gravel and sand are separated and removed therefrom, fine sand is separated and removed from the sludge water by a wet cyclone to obtain concentrated sludge water, and the concentrated sludge water is dehydrated to obtain a sludge cake. The sludge cake is put into a rotary drum, hot air and highly concentrated carbon dioxide are supplied into the rotary drum, the carbon dioxide is fixed and is crushed and dried to obtain carbon dioxide fixing sludge fine powder. Alternatively, the sludge cake is crushed and fractured to obtain sludge fine powder. This sludge fine powder is exposed to highly concentrated carbon dioxide to obtain carbon dioxide fixing sludge fine powder.

Abstract: The endoscope objective optical system includes in order from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. A lens surface positioned nearest to an image side in the second lens group is a concave surface which is directed toward the image side. The second lens group moves along an optical axis.

Abstract: The endoscope objective optical system includes in order from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. A lens surface positioned nearest to an image side in the second lens group is a concave surface which is directed toward the image side. The second lens group moves along an optical axis.

Abstract: The invention provides a rigid endoscope relay optical system that can be fabricated at lower costs while its brightness is kept intact by reducing parts count. The rigid endoscope optical system has an elongate insert and is adapted to implement image transfer using relay lenses Re1 to Re7. The relay lenses Re1 to Re7 each have at least two rod lenses and satisfy nd>2, where nd stands for the refractive index on d-line basis of each rod lens in the relay lens.

Abstract: The invention provides a rigid endoscope relay optical system that can be fabricated at lower costs while its brightness is kept intact by reducing parts count. The rigid endoscope optical system has an elongate insert and is adapted to implement image transfer using relay lenses Re1 to Re7. The relay lenses Re1 to Re7 each have at least two rod lenses and satisfy nd>2, where nd stands for the refractive index on d-line basis of each rod lens in the relay lens.

Abstract: The invention provides a wide-angle, low-cost endoscopic objective optical system that is reduced in terms of distortion and field curvature and composed only of spherical lenses, especially a video endoscopic objective optical system. The optical system comprises a first group G1 comprising a negative meniscus lens convex on an object side thereof, an aperture stop S, a second group G2 comprising a positive lens having a plane directed toward an object point side, a third group G3 including at least one concave refractive surface and having a positive refracting power as a whole, and a fourth group G4 comprising a cemented lens comprising a negative meniscus lens and a double-convex lens and having positive refracting power, so that an image is formed at an imaging device I via the first group G1 to the fourth group G4. A chief ray is reflected at the convex surface of the positive lens in the second group in a direction away from an optical axis.

Abstract: An objective lens includes, in order from the object side, a first lens (L1) with negative power, a second lens (L2) with positive power, an aperture stop (AS), and a third lens (L3) with positive power. A lens component located on the image side of the aperture stop (AS) is constructed with a positive single lens or a plurality of positive single lenses, and the objective lens satisfies the following conditions: 45<vd1?vd2 ?0.6<f1/f2<?0.3 where vd1 is the Abbe's number of the first lens, vd2 is the Abbe's number of the second lens, f1 is the focal length of the first lens, and f2 is the focal length of the second lens.

Abstract: An objective lens includes, in order from the object side, a first lens (L1) with negative power, a second lens (L2) with positive power, an aperture stop (AS), and a third lens (L3) with positive power. A lens component located on the image side of the aperture stop (AS) is constructed with a positive single lens or a plurality of positive single lenses, and the objective lens satisfies the following conditions: 45<vd1?vd2 ?0.6<f1/f2<?0.3 where vd1 is the Abbe's number of the first lens, vd2 is the Abbe's number of the second lens, f1 is the focal length of the first lens, and f2 is the focal length of the second lens.