Abstract: An optical system is provided. The optical system includes a first lens group that has a positive refractive power, a second lens group that has a negative refractive power, a third lens group that has a negative refractive power, a fourth lens group that has a positive refractive power, and a fifth lens group that includes one or more lens groups, in sequence from an object, wherein the first lens group and the fifth lens group are fixed and the third lens group moves parallel to an optical axis to perform focusing when adjusting a magnification of the optical system.

Abstract: A zoom lens includes: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; a fourth lens group having a negative refractive power; and a fifth lens group having a positive refractive power, wherein the first to fifth lens groups are sequentially arranged in a direction from an object side, during zooming from a wide-angle position to a telephoto position, the first to fifth lens groups are moved, the third lens group includes a first positive lens, a second negative lens, and a third positive lens, and the second negative lens of the third lens group includes a concave object-side surface. The zoom lens may be part of an electronic apparatus, such as a photographing apparatus.

Abstract: A zoom lens includes: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; a fourth lens group having a negative refractive power; and a fifth lens group having a positive refractive power, wherein the first to fifth lens groups are sequentially arranged in a direction from an object side, during zooming from a wide-angle position to a telephoto position, the first to fifth lens groups are moved, the third lens group includes a first positive lens, a second negative lens, and a third positive lens, and the second negative lens of the third lens group includes a concave object-side surface. The zoom lens may be part of an electronic apparatus, such as a photographing apparatus.

Abstract: There is provided an AMTEC (alkali metal thermal-electric converter) with a heat pipe and more particularly, to an AMTEC with a heat pipe minimized a heating part and a condensation part of the AMTEC and improved in efficiency of thermal to electric conversion through installing the heating and cooling heat pipes in the AMTEC, in which a metal fluid is heated by latent heat of an operating fluid of the heat pipe, instead of the heat conduction from a heat source, thereby reducing a temperature difference needed for heat transfer to vaporize the metal fluid even by a heat source of a lower temperature than a conventional heat source; improving a cooling performance in a condensation part to result in the high efficiency of thermal to electric conversion; using no additional driving components for driving the heat pipe.

Abstract: There is provided an AMTEC (alkali metal thermal-electric converter) with a heat pipe and more particularly, to an AMTEC with a heat pipe minimized a heating part and a condensation part of the AMTEC and improved in efficiency of thermal to electric conversion through installing the heating and cooling heat pipes in the AMTEC, in which a metal fluid is heated by latent heat of an operating fluid of the heat pipe, instead of the heat conduction from a heat source, thereby reducing a temperature difference needed for heat transfer to vaporize the metal fluid even by a heat source of a lower temperature than a conventional heat source; improving a cooling performance in a condensation part to result in the high efficiency of thermal to electric conversion; using no additional driving components for driving the heat pipe.

Abstract: A zoom lens system includes, arranged sequentially from an object side, a first lens group including at least one reflective optical member changing the optical path of an incident light ray, and having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a fourth lens group having positive refractive power, and during a magnification change from a wide-angle position to a telephoto position, the first lens group and the third lens group are not moved, the second lens group is moved from the object side towards an image side, and the fourth lens group is linearly moved from the image side towards the object side.

Abstract: A zoom lens system includes, arranged sequentially from an object side, a first lens group including at least one reflective optical member changing the optical path of an incident light ray, and having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a fourth lens group having positive refractive power, and during a magnification change from a wide-angle position to a telephoto position, the first lens group and the third lens group are not moved, the second lens group is moved from the object side towards an image side, and the fourth lens group is linearly moved from the image side towards the object side.

Abstract: A compact zoom lens suitable for an imaging optical system using a solid-state image sensing device is provided. The zoom lens includes a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power. The first through third lens groups are sequentially arranged from an object side toward an image side. The first, second, and third lens groups move when magnification changes from the wide-angle position to the telephoto position, and a refractive index G1n of at least one lens element included in the first lens group satisfies 1.90<G1n<2.00.

Abstract: The present invention relates to a process for preparing pravastatin sodium. More specifically, in the process for preparing pravastatin sodium by adding a precursor of the pravastatin to a microorganism-culturing medium to obtain pravastatin sodium, the precursor of the pravastatin is added to a culture medium that is culturing Streptomyces carbophilus KBT229 (KCCM-10317), which is obtained by UV-mutating a Streptomyces carbophilus FERM BP-1145, and cultured to obtain the pravastatin sodium with high density and high efficiency.

Abstract: A compact zoom lens suitable for an imaging optical system using a solid-state image sensing device is provided. The zoom lens includes a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power. The first through third lens groups are sequentially arranged from an object side toward an image side. The first, second, and third lens groups move when magnification changes from the wide-angle position to the telephoto position, and a refractive index G1n of at least one lens element included in the first lens group satisfies 1.90<G1n<2.00.

Abstract: A lens system and a portable device employing the lens system are provided. The lens system includes at least three lenses and an infrared cut filter disposed between any of the lenses to prevent redness from occurring at a center region of an image as the lens system is miniaturized. An angle ?1 at which light is incident on the infrared cut filter satisfies 14°??1?16°.

Abstract: An apparatus for measuring fruit properties, in order to classify fruit according to internal qualities, measures the sweetness of a fruit sample using near-infrared spectroscopy. The apparatus includes a pair of waveguides (12), a pair of optic emitter/sensor assemblies (14), a light-interrupting unit (20), and a light detector (40). The light detector calculates the intensity of light, transmitted from a light source and received by the optical emitter/sensor assemblies, thus allowing spectral analysis and interpretation for the determination of sweetness and acidity of a variety of fruits. The light detector controls the light-interrupting unit to interrupt the optical path when the light intensity is reduced. The apparatus is suitable for use in an automated line, for effective and reliable measurement of internal fruit properties, to improve operational efficiency and precision in fruit selection.

Abstract: A lens system and a portable device employing the lens system are provided. The lens system includes at least three lenses and an infrared cut filter disposed between any of the lenses to prevent redness from occurring at a center region of an image as the lens system is miniaturized. An angle ?1 at which light is incident on the infrared cut filter satisfies 14°??1?16°.

Abstract: The present invention relates to a process for preparing pravastatin sodium. More specifically, in the process for preparing pravastatin sodium by adding a precursor of the pravastatin to a microorganism-culturing medium to obtain pravastatin sodium, the precursor of the pravastatin is added to a culture medium that is culturing Streptomyces carbophilus KBT229 (KCCM-10317), which is obtained by UV-mutating a Streptomyces carbophilus FERM BP-1145, and cultured to obtain the pravastatin sodium with high density and high efficiency.